Neuro-Ophthalmology & Neuro-Otology
Isolated sixth nerve palsy
Dec. 07, 2022
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The author explains the clinical presentation, pathophysiology, diagnostic work-up, and management of vertigo. Vestibular vertigo is a common problem, affecting 5% or more of adults each year. Careful history, provocative testing, and detailed examination will allow distinction of the major categories of dizziness in most cases and will often allow a specific etiologic diagnosis as well.
• Vertigo is an illusion of movement due to an imbalance of tonic vestibular activity within the central or peripheral vestibular pathways.
• Vertigo is usually rotatory, implying a disturbance of the semicircular canals or their central connections. Sensations of body tilt or impulsion indicate otolithic disturbances or dysfunction of central otolithic connections.
• Vertigo is commonly associated with nystagmus, oscillopsia, postural imbalance, and autonomic symptoms (eg, sweating, pallor, nausea, vomiting).
• Vestibular vertigo is a common problem, affecting 5% or more of adults each year.
• Careful history, provocative testing, and detailed examination will allow distinction of the major categories of dizziness in most cases and will often allow a specific etiologic diagnosis as well.
• Episodic vertigo is generally of abrupt onset, but the duration of episodes varies considerably: episodes of benign paroxysmal positioning vertigo last seconds (up to a minute), whereas seizures generally last seconds or minutes, migrainous vertigo may last minutes to days, transient ischemic attacks last minutes to hours (up to a day by definition, but generally less than 6 hours), and attacks of Ménière syndrome last hours.
• Monophasic vertigo may have an abrupt onset (eg, with trauma, stroke, or demyelinating disease), a subacute onset (eg, with vestibular neuronitis), or a subacute to chronic onset (eg, with toxic vestibulopathy or posterior fossa masses).
• Peripheral vestibular nystagmus is a mixed linear-rotatory jerk nystagmus that beats in one direction away from a hypofunctioning labyrinth.
• Drugs should be reviewed in all patients with dizziness, whether clearly vertiginous or not. Drugs associated with dizziness include alcohol and other CNS depressant medications (eg, benzodiazepines, barbiturates, phenothiazines), aminoglycoside antibiotics, anticonvulsants, antidepressant medications, antihypertensive medications, chemotherapeutic agents, loop diuretics (eg, furosemide), and salicylates.
• The elderly are particularly susceptible to drug ototoxicity.
• Occupational exposure of healthcare and research staff to static magnetic stray fields from MRI scanners is associated with transient symptoms, particularly vertigo and dysgeusia (metallic taste sensations).
• In patients with acute, persistent vertigo from peripheral vestibular lesions, recovery occurs more rapidly and more completely when vestibular exercises are begun as soon as possible after the onset of symptoms.
• Severe forms of acute, persistent vertigo are especially distressing, particularly when accompanied by nausea and vomiting; antivertiginous medications with both sedative and antiemetic effects are helpful in these situations (eg, promethazine, droperidol, dimenhydrinate).
• Vestibular paroxysmia, a neurovascular compression syndrome of the eighth cranial nerve, is often readily amenable to pharmacological treatment with carbamazepine or oxcarbazepine. It is characterized by brief attacks of vertigo lasting seconds to minutes, often occurring multiple times daily, with accompanying nystagmus and unsteadiness of stance or gait.
English physician Erasmus Darwin (1731-1802), the grandfather of naturalist Charles Darwin (1809-1882), described physiologic vertigo, its dependence on rotation, and many of the subjective phenomena associated with it, in the late 1700s and early 1800s (33). Subsequently, other important early 19th century contributions to vestibular physiology were made by Purkinje and Flourens (12; 141). From 1820 to 1827 Czech anatomist and physiologist Jan Evangelista Purkyně (also written Johann Evangelist Purkinje; 1787-1869) established the method of rotation to study vertigo, thoroughly described apparent movement of the visual field during and after rotation and discovered that the axis of apparent after-rotation varies with the position of the head; this, in turn, suggested that the organ for perception of rotation must lie in the head (12). From 1824 to 1830 French physiologist Jean Pierre Flourens (1794-1867) performed and reported key studies, showing the section of semicircular ducts that produces muscular incoordination that is maximal in the plane of the sectioned canals (12).
In the 1870s considerable progress was made in understanding the function of the peripheral vestibular system (12; 142). In 1870 German physiologist Friedrich Leopold Goltz (1834-1902) found that caloric irrigation of the external auditory canal produced vertigo, nausea, and nystagmus. In 1871 German neurologist and neuropsychiatrist Eduard Hitzig (1839-1907) produced similar phenomena with electric currents applied to the head (12). Goltz also argued that orientation is due to the pattern of pressures in the three semicircular ducts, an idea subsequently developed independently by Mach, Breuer, and Crum-Brown from 1873 to 1875 (12; 86; 87; 84). Austrian physicist and philosopher Ernst Mach (1838-1916) proposed in 1873 that a change in speed of rotation (ie, angular acceleration) would produce pressures within the semicircular ducts that would vary in intensity as a function of the components of rotation in the planes of the respective canals (12; 86). Mach also proposed that the maculae in the vestibular otolithic organs were responsible for sensing linear acceleration (86). Austrian physician and physiologist Josef Breuer (1842-1925) and British physician and theoretical organic chemist Alexander Crum-Brown (1838-1922) described similar results in 1874 and 1875, respectively (12; 87; 84). Though Mach had assumed that each canal sensed both clockwise and counterclockwise rotations in its own plane, Crum-Brown doubted this, and noted that the symmetrical pattern of the canals on the two sides of the head made this unnecessary (12; 84). Thus, canals in the same plane on the left and right sides of the head were reversed in function, with counterclockwise rotation stimulating one, and clockwise rotation stimulating the other.
The osseous labyrinth housing the vestibular receptors lies in the petrous temporal bone, with the three semicircular canals on each side oriented roughly orthogonally to one another, and in such a fashion that (1) the superior canal on one side is in approximately the same plane as the posterior canal on the opposite side, and (2) the lateral (“horizontal” or external) canals are in approximately the same plane. The membranous labyrinth lies within the osseus labyrinth, and includes the three semicircular ducts for sensing rotary motions of the head, and the utricle and saccule for sensing linear accelerations.
• Vertigo is an illusion of movement due to an imbalance of tonic vestibular activity that is commonly associated with nystagmus, oscillopsia, postural imbalance, and autonomic symptoms (eg, sweating, pallor, nausea, vomiting).
• Most patients with central positional vertigo have clinical findings indicative of a central lesion, such as downbeat and apogeotropic horizontal nystagmus, cerebellar ocular motor abnormalities, and truncal ataxia indicative.
• The so-called “acute vestibular syndrome” is characterized by the acute onset of vertigo or dizziness, intolerance of head motion, spontaneous or gaze-evoked nystagmus, gait unsteadiness, and a duration of at least 24 hours.
Vertigo is an illusion of movement due to an imbalance of tonic vestibular activity (15; 56; 58; 132; 85). It is usually rotatory, but sensations of body tilt or impulsion may also occur. Vertigo is commonly associated with nystagmus, oscillopsia, postural imbalance, and autonomic symptoms (eg, sweating, pallor, nausea, vomiting). Unfortunately, the term is used inconsistently by clinicians (11).
Precipitating factors for vertigo may include head movements (56), coughing, sneezing, and loud noises. Head movements attribute to imbalance within vestibular pathways and may produce vertigo even after compensation has occurred in response to a vestibular lesion. In addition, positional vertigo is frequently induced by ordinary head movements, such as looking up or to one side, lying down, sitting up, or bending over. Coughing and sneezing may precipitate vertigo, particularly by changing middle ear pressure in patients with a post-traumatic perilymph fistula. Loud noises may also precipitate vertigo in patients with inner ear disease, such as Ménière disease; this is called the Tullio phenomenon.
Most patients with central positional vertigo have clinical findings indicative of central lesions, such as downbeat and apogeotropic horizontal nystagmus, cerebellar ocular motor abnormalities, and truncal ataxia indicative. In one study, 62% of patients with central positional vertigo have paroxysmal attacks, whereas 31% had nonparoxysmal vertigo, and 8% had paroxysmal-evolving-to-nonparoxysmal vertigo (35). The most common patterns of positional nystagmus evoked with maneuvers were positional downbeat nystagmus (69%), apogeotropic horizontal nystagmus (42%), geotropic (8%), and multiplanar (23%). Half of the patients in this series had brain imaging before central positional nystagmus was on the differential diagnosis. Findings of downbeat or apogeotropic horizontal nystagmus alone were enough to diagnose central positional vertigo in half of the patients in this series, which, as the authors note, underscores “the importance of clinical evaluation in a time when an ‘imaging-first’ philosophy is gaining popularity in Neurology” (35).
The so-called “acute vestibular syndrome” is characterized by the acute onset of vertigo or dizziness, intolerance of head motion, spontaneous or gaze-evoked nystagmus, gait unsteadiness, and a duration of at least 24 hours (64; 71; 27; 110; 111; 09; 96; 22; 41; 41; 139). This specific subset of acute dizziness patients has been categorized to help identify, in conjunction with specified examination findings, patients with acute stroke who present with acute vertigo or dizziness to emergency rooms. The problematic inclusion, by definition, of a specified duration of at least 24 hours makes this a presumptive consideration in most emergency room situations in which it is entertained because most patients present before that time threshold has been reached. Furthermore, critical decision-making (eg, administration of intravenous tissue plasminogen activator or endovascular procedures) has to be made before this time threshold.
Postural instability associated with vertigo varies by etiology, age, residual vestibular function, and disease duration (48). Truncal ataxia has been categorized in a 4-point grading system: grade 0, no imbalance with walking independently; grade 1, mild to moderate imbalance with walking independently; grade 2, severe imbalance with standing and unable to walk without support; and grade 3, falling with upright posture (91; 22). In patients with acute vestibular syndrome, grade 3 truncal ataxia is strongly suggestive of acute stroke, as is grade 2 truncal ataxia in combination with other central nervous system signs, such as nystagmus of central origin (22).
Although the prognosis and complications of vertigo are heavily dependent on the underlying causes, vertigo (like the broader category of dizziness) is an important contributor to population-attributable disability, particularly among the aged, and is often associated with significant comorbidities and serious consequences, including falls, traumatic injuries, loss of autonomy, and institutionalization (101; 102; 153; 120; 151). Psychological distress is an important component of vertigo-related handicap (120). Vertigo is strongly associated with both an increased tendency to fall and an increased injury rate from falls among adults. In children, chronic vertigo has a negative impact on health-related quality of life (34).
In addition, because of the sudden, dramatic, and unpleasant associated sensations and from fear of falling, injury, or death, vertigo is often associated with psychological distress, anxiety, and depression (85; 66; 82; 153). Anxiety and depression are more common in some types of vertigo than others, possibly as a function of ability of patients to exert control over recurrent or persistent symptoms (40; 153): in particular, anxiety and depression are more common in patients with Ménière disease and migrainous vertigo than in those with benign paroxysmal positioning vertigo or vestibular neuritis (40; 153). Persistence of dizziness following an episode of benign positional vertigo is correlated with mental stress that is affected by the duration and recurrence of benign positioning vertigo, age, and gender (45).
Case 1. A 57-year-old man with a history of alcohol abuse (who had reportedly stopped drinking) was referred for evaluation of acute onset of dizziness and falls. He reported sudden onset of dizziness, imbalance, vertical diplopia, and numbness on the right side of the face and in the left leg. The dizziness began as a spinning sensation that gradually subsided over several days. Initially, he needed to hold onto something or someone in order to stand. When he attempted to walk, he staggered and often felt as if he were being thrown to the right. All of these symptoms improved considerably over time. He was able to walk unassisted but had occasional falls. He was on some medications for high blood pressure but was not taking them regularly. He had smoked one pack of cigarettes a day for the past 40 years. He was not taking aspirin on any regular basis.
On examination, mental status testing was normal. He had prominent anisocoria with a right ptosis and myosis consistent with a right Horner syndrome. In addition, he had a left hypertropia and nystagmus. He had full ocular duction. He had right facial hypesthesia, but no evident facial weakness. He was not dysarthric, but he had been dysarthric shortly after the onset of his problems. The palate elevated symmetrically, but his gag was decreased on the right. His tongue protruded midline. He had a slight right head tilt. Motor examination showed normal bulk, tone, and power throughout. He had mild dysmetria of his right arm on finger-nose-finger testing. He had no drift of his outstretched upper extremities. He was able to stand and walk independently, although he felt uncomfortable and unsteady doing this, and his gait was slightly wide-based. He tended to fall toward the right. Muscle stretch reflexes were brisk in the lower extremities. His plantar responses were flexor. Sensation was decreased to pinprick in the left leg but not in the left arm.
This patient had acute onset of vertigo associated with neurologic signs that persisted for days. In his age group, the most likely cause would be a stroke. Examination confirmed a Wallenberg syndrome.
Case 2. A 53-year-old woman had a 6- to 7-week history of episodic dizziness and vertigo that began when she had a "bad cold" and was confined to bed for several days. Following this, she became "dizzy" when she got up in the morning and said that the "room was spinning" during these episodes. She said the episodes usually lasted 5 minutes, but she once had an episode that was more prolonged and severe, lasting 15 minutes. She became nauseated but did not vomit. These spells also happened when she bent down or raised her head up and looked backward. There were no other associated symptoms, including no visual symptoms, no numbness or weakness in the extremities, etc. Her family physician obtained a CT scan that was normal. She was started on meclizine for her complaints, but this produced no change.
On examination, mental status testing was normal. Cranial nerves showed equal and reactive pupils; there was no spontaneous nystagmus. Visual fields were full. Funduscopic examination was normal, and extraocular movements were intact. There was no facial weakness or asymmetry; auditory acuity was normal. Weber test did not lateralize. Air conduction was greater than bone conduction bilaterally, and tympanic membranes were normal bilaterally. The palate elevated symmetrically, and there was no dysarthria. The tongue protruded midline and the sternomastoid and trapezius muscles were strong bilaterally. Motor examination showed normal bulk, tone, and power throughout. There was no drift of the outstretched upper extremities. Gait, toe walking, heel walking, and tandem gait were all performed normally. Finger-nose-finger testing was performed normally. There was no past-pointing. Reflexes were 2+ and symmetric. Plantar responses were flexor. Sensation was intact to light touch and joint position sense. Romberg sign was absent.
A Dix-Hallpike maneuver performed with the head turned toward the right did not produce any nystagmus. With repetition of the maneuver with the head turned toward the left, she developed an upbeating rotatory nystagmus after a latency of 5 to 10 seconds. This subsided after an additional 10 seconds to 15 seconds. Repetition of this maneuver resulted in identical symptoms, although of lesser severity. She developed rebound nystagmus when she sat up after each maneuver with her head turned toward the left.
This patient had episodic vertigo that was relatively brief by her report. Examination excluded static vestibular dysfunction and established a diagnosis of benign paroxysmal positioning vertigo referable to her left posterior semicircular duct. She was treated with a Semont liberatory maneuver with resolution of her symptoms and signs.
• Vertigo indicates dysfunction or imbalance within the central or peripheral vestibular pathways.
• Vertigo is usually rotatory, implying a disturbance of the semicircular canals or their central connections.
• Sensations of body tilt or impulsion indicate otolithic disturbances or dysfunction of central otolithic connections.
• Hearing loss and tinnitus generally imply peripheral dysfunction that usually involves the inner ear but occasionally involves the internal auditory canal or the structures of the cerebellopontine angle.
• Because the motor fibers for facial expression pass in the seventh cranial nerve in close proximity to the vestibulocochlear sensory fibers in the eighth cranial nerve, peripheral-type facial paresis (involving both upper and lower facial muscles) may be associated with lesions of the internal auditory canal, cerebellopontine angle, or brainstem.
• Any of the following imply an intracranial basis for the dysfunction: diplopia, facial numbness, dysarthria, dysphagia, extremity weakness or numbness, or incoordination.
• Patients with vertigo often give confusing and contradictory accounts of the directionality of their symptoms, most likely because the vestibular and self-referred visual sensations of movement are oppositely directed. Therefore, it is helpful to determine the direction of the sensation of rotation of the body with the eyes closed, as this directional sensation is away from the side of a peripheral vestibular lesion.
• The vestibular receptors are housed in the bony labyrinth, a series of intercommunicating cavities and hollow channels in the petrous portion of the temporal bones bilaterally.
• The three semicircular ducts are oriented orthogonally, with the lateral duct oriented roughly horizontally and the anterior and posterior ducts oriented vertically so that the anterior duct on one side is in the same plane as the posterior duct on the opposite side. The lateral or "horizontal" duct is actually tilted 30 degrees from the horizontal plane; the head must be tilted 30 degrees forward from upright to make the duct orientation truly horizontal.
• Physiologic imbalances in neural discharges within the vestibular system are produced with head movements, rotation, and caloric stimulation.
• Pathological imbalances in the vestibular system can be produced by impairments either in the vestibular inputs or in the central connections of the vestibular system.
• Vertigo results from a mismatch between the converging inputs and the expected sensory patterns.
• The clinical manifestations of vestibular tone imbalance are produced through various vestibulo-ocular and vestibulospinal reflexes, as well as through the connections of the central vestibular system to cortical and brainstem centers.
Vertigo indicates dysfunction or imbalance within the central or peripheral vestibular pathways. Vertigo is usually rotatory, implying a disturbance of the semicircular canals or their central connections. Sensations of body tilt or impulsion indicate otolithic disturbances or dysfunction of central otolithic connections.
Neurologic symptoms associated with vertigo are particularly helpful in localizing the responsible lesions. Hearing loss and tinnitus generally imply peripheral dysfunction that usually involves the inner ear, but occasionally involves the internal auditory canal or the structures of the cerebellopontine angle. Because the motor fibers for facial expression pass in the seventh cranial nerve in close proximity to the vestibulocochlear sensory fibers in the eighth cranial nerve, peripheral-type facial paresis (involving both upper and lower facial muscles) may be associated with lesions of the internal auditory canal, cerebellopontine angle, or brainstem (62). Any of the following imply an intracranial basis for the dysfunction: diplopia, facial numbness, dysarthria, dysphagia, extremity weakness or numbness, or incoordination.
Patients with vertigo often give confusing and contradictory accounts of the directionality of their symptoms, most likely because the vestibular and self-referred visual sensations of movement are oppositely directed. Therefore, it is helpful to determine the direction of the sensation of rotation of the body with the eyes closed, as this directional sensation is away from the side of a peripheral vestibular lesion. However, even normal subjects during caloric irrigation report subjective sensations other than spinning and rotating 20% to 25% of the time, and these tend to be associated with lower peak slow-phase velocities (99).
Rare patients with cerebral lesions present with vertigo and imbalance (104; 116; 136). Recurrent episodes of vertigo and imbalance have been associated with small lesions in the anterior insula (116). In previous imaging studies, the posterior insular cortex was identified as an essential area for vestibular otolith perception and was considered a core region of the human vestibular cortical network (03). However, lesions exclusively restricted to the posterior insular cortex do not by themselves produce signs of vestibular otolith dysfunction (03). Apparently, posterior insular cortex lesions have to be combined with lesions of adjacent regions of the cortical and subcortical vestibular network to cause vestibular otolith deficits (03). Acute vertigo has been associated with a left parietal infarction involving the supramarginal gyrus (104) and with small convexity meningiomas in the parietal area (136).
Cortical stimulations studies in epileptics have identified vestibular cortical areas in both the temporal and parietal lobes, although epileptic discharges in patients with epileptic vertigo have been observed in a wider range of areas (including the frontal lobe and temporal-parietal-occipital junction) (76). Vertigo or dizziness is a common aura in patients with epilepsy undergoing video-EEG monitoring; the temporal lobe is the most frequent ictal-onset area in these patients, but some patients had ictal onset in each of the other lobes of the brain (76). However, the cortical area generating the aura of vertigo or dizziness is not necessarily either the ictal-onset area or the area in which cortical stimulation elicited dizziness or vertigo (76). This may be due to processing of vestibular-related neural activity across large cortical regions or the spread of excitation across adjoining areas (76).
Kim and colleagues reviewed the charts of patients who had video-EEG monitoring and had at least one habitual seizure recorded during monitoring, 93% of whom had partial seizures (76). Three hundred and seventy-four of 831 patients (45%) experienced at least one aura, and of these 374 patients, vertigo or dizziness was the most frequently encountered aura (40 patients, 4.8% of the sample population and 5.2% of those with partial seizures). All 40 patients with vertigo or dizziness as an aura had partial seizures. Most involved the medial or lateral temporal lobe (28 of 40; 70%), but some had frontal, parietal, or occipital lobe onset.
The vestibular receptors are housed in the bony labyrinth, a series of intercommunicating cavities and hollow channels in the petrous portion of the temporal bones bilaterally. From a central cavity called the vestibule arise three semicircular canals and the cochlea. Within this bony labyrinth is the membranous labyrinth, a series of intercommunicating sacs and ducts filled with endolymphatic fluid and specialized structures for vestibular and auditory sensation. The vestibular portion of the membranous labyrinth includes the utricle and saccule within the vestibule and the semicircular ducts within the semicircular canals. Between the two labyrinths is a space containing perilymphatic fluid, a connective tissue network, and blood vessels. The membranous labyrinth and its neural structures receive their vascular supply from the internal auditory artery that usually originates from a branch of the basilar artery.
The three semicircular ducts are oriented orthogonally, with the lateral duct oriented roughly horizontally and the anterior and posterior ducts oriented vertically, so that the anterior duct on one side is in the same plane as the posterior duct on the opposite side. The lateral or "horizontal" duct is actually tilted 30 degrees from the horizontal plane; the head must be tilted 30 degrees forward from upright to make the duct orientation truly horizontal.
Sensory information from the vestibular receptor organs is conveyed centrally by the eighth cranial nerve, through the internal auditory canal in conjunction with the facial nerve, into the posterior fossa to synapse in the vestibular nuclei and cerebellum. The vestibular nuclei are situated in the brainstem on the floor of the fourth ventricle. The vestibular nuclei and brainstem reticular formation integrate inputs from the vestibular receptors, the visual system, the proprioceptive pathways, and the cerebellum. The vestibular nuclei, in turn, project to the parieto-temporal cerebral cortex, brainstem ocular motor and autonomic nuclei, and the spinal cord. Projections to the parieto-temporal cerebral cortex are responsible for motion perception and spatial orientation. The connections with the ocular motor nuclei mediate vestibulo-ocular reflexes; vestibulo-ocular reflexes produce eye movements in the orbit that are equal in amplitude and opposite in direction to head movements so that gaze remains steady. The projections to the spinal cord mediate vestibulospinal reflexes that assist in maintaining posture and balance, particularly through tonic influence on the antigravity muscles.
Physiologic imbalances in neural discharges within the vestibular system are produced with head movements, rotation, and caloric stimulation. Pathological imbalances in the vestibular system can be produced by impairments either in the vestibular inputs or in the central connections of the vestibular system. Vertigo results from a mismatch between the converging inputs and the expected sensory patterns. For example, acute unilateral labyrinthine dysfunction produces vertigo because the sensation of self-motion associated with the vestibular tone imbalance is inconsistent with expectations based on visual and somatosensory information. The vertigo ultimately resolves, usually because of a rebalancing centrally rather than a return of function peripherally, ie, central compensation corrects the mismatch between inputs and expectations.
The clinical manifestations of vestibular tone imbalance are produced through various vestibulo-ocular and vestibulospinal reflexes, as well as through the connections of the central vestibular system to cortical and brainstem centers. A disturbance of cortical spatial orientation produces the sensation of vertigo. Nystagmus is due to a direction-specific imbalance in the vestibulo-ocular reflexes. If eye movements do not match head movements, then images move across the retina, producing blurred vision and an illusory visual sensation of environmental motion called oscillopsia. Postural imbalance is caused by abnormal activation of monosynaptic and polysynaptic vestibulospinal pathways. Finally, nausea and vomiting are due to activation of the medullary-vomiting center.
• Vestibular vertigo is a common problem, affecting 5% or more of adults each year.
• Dizziness and vertigo are associated with significantly increased utilization of healthcare resources and result in significantly more related costs for both primary and pertinent secondary care.
Vestibular vertigo is a common problem, affecting 5% or more of adults each year (108; 106), with an annual incidence of 1.4% in adults (106). Its prevalence rises with age and is about 2 to 3 times higher in women than in men (106; 83). Vertigo tends to recur, particularly among older women (83).
A systematic review of a case series of dizziness and vertigo demonstrated significant differences in the proportions of particular diagnoses for patients presenting with dizziness or vertigo, depending on the specialty making the diagnosis (117). Otolaryngology diagnoses were dominated by benign paroxysmal positioning vertigo, psychogenic dizziness, and Ménière disease, whereas emergency room diagnoses were dominated by cardiac, neurologic, and “other” categories (117). Analysis over time revealed increasing temporal trends for some diagnoses, such as benign paroxysmal positioning vertigo and vestibular migraine, and a corresponding decreasing trend for diagnoses of Ménière disease (117). This undoubtedly reflects improved recognition of some forms of vertigo with episodic presentations (ie, benign paroxysmal positioning vertigo and vestibular migraine) that were frequently “lumped in” with Ménière disease. More work needs to be done before acute monophasic vertigo is correctly categorized as it continues to be frequently labeled “vestibular neuritis,” even when it is clearly not.
Gender, stress, muscular pain in the neck and shoulder region, sleep duration, and migraine were identified as independent risk factors for vertigo and dizziness in adolescents (47). The population attributable risk explained by these risk factors was 26%.
Sleep apnea is a risk factor for vertigo in adults (134).
Among emergency department patients, age, history of hypertension, history of coronary artery disease, and vertigo unresponsive to emergency department treatment were all significantly associated with a central cause of vertigo (01).
A cohort study of 1716 hypertensive patients recruited in the 1970s categorized patients as not dizzy, vertiginous, or nonvertiginous dizziness (32). The presence of dizziness had no impact on the risk for all-cause mortality, cardiovascular mortality, or stroke mortality. Only vertigo had a prognostic impact. The increased risk was particularly marked on stroke death, with a hazard ratio of 2.4 (95% confidence interval 1.3-4.5) versus patients without dizziness and 2.2 (95% confidence interval 1.2-4.1) versus patients with dizziness excluding vertigo.
A study of 77,993 patients admitted to the hospital after presenting to the emergency department with dizziness, vertigo, or imbalance examined predictors of acute ischemic stroke (79); independent predictors of acute ischemic stroke were an admission presentation of imbalance, African-American race, history of hypertension, diabetes mellitus, hypercholesterolemia, tobacco use, atrial fibrillation, and prior acute ischemic stroke due to extracranial artery atherosclerosis, whereas negative predictors of acute ischemic stroke included an admission presentation of vertigo, female sex, older than 81 years of age, history of anemia, coronary artery disease, asthma, depressive disorders, and anxiety disorders.
Dizziness and vertigo are associated with significantly increased utilization of healthcare resources and result in significantly more related costs for both primary and pertinent secondary care (143).
Patients with systemic cancer have a significantly higher risk of brain metastases if they report vertigo coexistent with any of the following: headache, ataxia, seizures, visual symptoms, speech impairment, altered mental status, focal weakness, or focal sensitive complaint (21).
Based on a cross-sectional analysis of the Child Balance Supplement of the 2012 National Health Interview Survey administered to parents/caregivers of children in the United States, the 1-year prevalence of vertigo was 1.6% in this nationally representative sample of nearly 10,823 U.S. children aged 3 to 17 years (08). Vertigo was associated with significantly increased odds of cognitive and psychiatric comorbidity. Specifically, after adjusting for demographic factors and confounding health conditions, children with vertigo had significantly higher odds of attention deficit disorder, learning disability, developmental delay, and intellectual disability, and they were more likely to utilize special education services relative to nonvertiginous children (08). Children with vertigo also had higher odds of having a poor attention span and having difficulty with emotions, concentration, or behavior (08).
In a hospital-based study of 301 patients experiencing vertigo, of which 56 (19%) had stroke, older age (≥ 60 years), diabetes, atrial fibrillation, previous history of vertigo or inner ear disease, focal muscle weakness, dysphagia, or ataxia were associated with a higher risk of stroke (155).
Careful history, provocative testing, and detailed examination will allow distinction of the major categories of dizziness in most cases and will often allow a specific etiologic diagnosis as well. Particular attention should be given to the onset, duration, and course of the vertigo, as well as any associated autonomic, auditory, or central nervous system signs and symptoms. This information alone is often sufficient to suggest a specific etiologic diagnosis.
Vertigo is usually rotatory, and patients frequently describe it as "spinning," but they may also describe sensations of body tilt or impulsion. Vertigo is commonly associated with nystagmus, oscillopsia, postural imbalance, nausea, and vomiting. Autonomic symptoms (eg, sweating, pallor, nausea, vomiting) are generally more severe with vertigo of peripheral origin than with vertigo of central origin.
Elderly patients. Frequency of symptoms and dizziness handicap increase with age; however, older patients less frequently report coexisting symptoms, such as nausea, headache, tinnitus, ear pressure, and visual impairment (144). Multisensory deficit, central vertigo, bilateral vestibulopathy, and benign paroxysmal positioning vertigo are more common in elderly patients, whereas persistent postural-perceptual dizziness and vestibular migraine are more common in younger age groups (144).
Common causes of vertigo in the elderly include benign paroxysmal positioning vertigo, viral neurolabyrinthitis, trauma, toxins, migraine, and posterior circulation or labyrinthine ischemia, particularly associated with posterior inferior cerebellar artery or anterior inferior cerebellar artery ischemia (91; 135; 71; 23; 27; 154; 110; 109; 127; 139).
The proportion of elderly patients with cerebrovascular events among patients presenting with dizziness, vertigo, or imbalance is low (73; 75; 105; 74), but a thorough evaluation is nevertheless warranted to exclude a stroke, particularly a stroke involving the cerebellum or lateral medulla and pons, because the consequences of missing this diagnosis can be severe. Isolated vertigo can rarely be the only initial symptom in patients with an acute posterior circulation ischemic stroke or hemorrhage, and this can even more rarely mimic peripheral vertigo (65; 100; 130; 127; 90). Small ischemic strokes presenting with severe vertigo may be caused by lacunar and nonlacunar mechanisms (eg, vertebral artery occlusions or dissections), with nonlacunar mechanisms representing about half of such cases (127). A presenting complaint of gait instability or imbalance, in conjunction with subtle neurologic findings, may help suggest an acute stroke as a cause of acute persistent vertigo, especially in patients over age 60, whereas dizziness symptoms in isolation are rarely associated with serious underlying pathology, particularly following a careful history and examination (25; 105; 130).
Diabetes appears to be an important risk factor for acute stroke in patients presenting to an emergency room with acute persistent vertigo (100). Such patients with vertigo also have a higher risk of subsequent stroke (65; 105), although this may simply reflect less than complete recognition of symptomatic cerebrovascular disease on initial presentation (95). Risk factors for subsequent stroke in such vertigo patients include the following: middle aged male, diabetes, hypertension, dyslipidemia, coronary artery disease, and atrial fibrillation–all of which are standard stroke risk factors (65).
Pediatric patients. In a retrospective case series of 257 children with dizziness aged 1 to 17 years (42% male, 58% female) referred to a tertiary pediatric otorhinolaryngology center from 2015 to 2020, dizziness was classified as central in 19%, peripheral vestibular in 12%, hemodynamic in 11%, psychological/psychogenic in 6%, and unclassified in 44% (13). Of children with "central" vertigo, 41% had benign paroxysmal vertigo of childhood (7.8% of all children), and 8% had migraine-associated vertigo.
Young adults. Common causes of vertigo in young adults include migraine-associated vertigo, viral neurolabyrinthitis, psychogenic dizziness, Ménière syndrome, trauma, toxins, and demyelination (107; 43; 67; 121). Common causes of vertigo in children include migraine-associated vertigo, benign paroxysmal vertigo, otitis media, viral neurolabyrinthitis, and trauma (29; 124; 80; 150; 67; 54; 66).
Episodic vertigo. Episodic vertigo is generally of abrupt onset, but the duration of episodes varies considerably. Episodes of benign paroxysmal positioning vertigo last seconds (up to a minute), whereas seizures generally last seconds or minutes, migrainous vertigo may last minutes to days (43), transient ischemic attacks last minutes to hours (up to a day by definition, but generally less than 6 hours), and attacks of Ménière syndrome last hours. Among causes of episodic vertigo, benign paroxysmal positioning vertigo, migraine, and Ménière syndrome are most commonly associated with autonomic symptoms. Similarly, transient ischemic attacks, migraine, and seizures are associated with central nervous system symptoms or signs. Ménière syndrome typically has episodes accompanied by auditory symptoms.
Vestibular paroxysmia is a neurovascular compression syndrome of the eighth cranial nerve that has been most commonly reported in adults, but that may also affect children, and that is often readily amenable to pharmacological treatment (16; 63; 06; 24; 93; 18). Vestibular paroxysmia is characterized by brief attacks of vertigo lasting seconds to minutes, often occurring multiple times daily, with accompanying nystagmus and unsteadiness of stance or gait, and with associated hyperacusis or tinnitus, either permanently or during the attack (16; 63; 93; 18). Between vertiginous attacks, hyperventilation-induced nystagmus may be demonstrated in the majority of tested patients (70%) (63). Attacks are frequently precipitated by particular head positions, and the duration of attack may be modified by changing head position (so-called “disabling positional vertigo”) (16).
Monophasic vertigo. Monophasic vertigo may have an abrupt onset (eg, with trauma, stroke, or demyelinating disease), a subacute onset (eg, with vestibular neuronitis), or a subacute to chronic onset (eg, with toxic vestibulopathy or posterior fossa masses). Autonomic symptoms and auditory symptoms are most common and generally most severe with peripheral vestibulopathies, such as with vestibular neuronitis or toxic vestibulopathies. Peripheral vestibulopathies are not associated with central nervous system symptoms and signs, whereas they are common or typical for the other causes of monophasic vertigo.
Occupational exposure of healthcare and research staff to static magnetic stray fields from MRI scanners is associated with transient symptoms, particularly vertigo and dysgeusia (metallic taste sensations) (129); awareness of this phenomenon can help the physician avoid unnecessary investigations in individuals with such occupational exposures.
• The history and physical examination are frequently sufficient to classify vague complaints of dizziness into one of the major categories such as vertigo, and perhaps even to suggest an etiologic diagnosis.
• Patients' descriptions of dizzy sensations are confusing, particularly when the events are episodic. Therefore, provocative testing is helpful in defining the subjective sensation and often the vague or misleading descriptions of dizziness and vertigo. Provocative testing can be used to produce physiologic sensations of vertigo that can then be compared and contrasted with the subjective sensations experienced by the patient.
• Vestibular imbalance is indicated by nystagmus, past-pointing, and postural and gait abnormalities.
• Because different types of nystagmus have different clinical implications, it is important to carefully characterize nystagmus both by its appearance and by any precipitating and inhibiting factors.
• Peripheral vestibular nystagmus is a mixed linear-rotatory jerk nystagmus that beats in a single direction away from a hypofunctioning labyrinth.
• The Dix-Hallpike positioning test is used to precipitate vertigo in patients with episodic symptoms, especially when the symptoms appear to be related to either head position or head movements. The Dix-Hallpike positioning test is a test for positionally induced nystagmus, particularly that associated with benign paroxysmal positioning vertigo.
• The presence of any of the following suggests a central cause for the positional/positioning nystagmus: (1) the nystagmus begins immediately on assuming the offending head position; (2) the nystagmus has a pendular appearance; (3) the nystagmus is purely rotatory or purely linear; (4) the nystagmus changes direction with gaze in different directions; (5) the nystagmus is not suppressed with fixation; (6) the nystagmus continues indefinitely with maintenance of the offending head position; (7) the nystagmus persists with repetition of the offending head positioning; (8) vertigo is mild or absent; (9) nausea is absent; or (10) there are central neurologic signs or symptoms.
• The head impulse test (HIT), or head thrust test, utilizes corrective saccades after single rapid head turns to help identify the side of vestibular dysfunction, particularly when spontaneous nystagmus is absent.
• The so-called “H.I.N.T.S.” or “HINTS” examination (ie, Head Impulse test, Nystagmus type, and Test-of-Skew) combines an assessment of the head impulse test (HIT), assessment of direction-changing horizontal nystagmus evoked by lateral gaze to the right and left, and assessment of vertical skew deviation by alternate cover testing.
History and physical examination. The history and physical examination are frequently sufficient to classify vague complaints of dizziness into one of the major categories such as vertigo, and perhaps even to suggest an etiologic diagnosis (37; 38; 39; 85). A variety of questionnaire-based studies have cast a negative light on the history-based differentiation of different types of dizziness, and indeed many patients are vague with initial questioning or use terms such as “spinning” indiscriminately to refer to different types of sensations (49). An astute clinician, with a careful approach, clarifying questions, and periodic reframing of the patient’s statements, can usually accurately categorize the type or types of dizziness involved.
Patients' descriptions of dizzy sensations are confusing, particularly when the events are episodic. Therefore, provocative testing is helpful in defining the subjective sensation and often the vague or misleading descriptions of dizziness and vertigo. Provocative testing can be used to produce physiologic sensations of vertigo that can then be compared and contrasted with the subjective sensations experienced by the patient (37; 85). Physiologic vertigo can be induced in the office either by rotational or caloric testing. Rotational testing in the office is performed by seating the patient in a rotary office chair with the head tilted 30 degrees forward, and then rotating the patient carefully 10 times over 20 seconds to 30 seconds. Tilting the head forward 30 degrees places both horizontal semicircular canals parallel to the floor; therefore, perpendicular to the axis of rotation in the chair. As a result, both horizontal ducts are affected with rotational testing, with output from one duct stimulated whereas output from the other duct is inhibited. The mismatch between the resulting vestibular imbalance and visual and somatosensory information produces physiologic vertigo that generally lasts less than 1 to 2 minutes. During this time, the physician can observe peripheral vestibular nystagmus and past-pointing. Because of the risk of falls and injury, patients should not stand until the vertigo has resolved. Vertigo can also be produced with caloric testing, eg, by injecting cold or warm water into the patient’s external auditory canal; however, this is generally much more uncomfortable for the patient than rotational testing and is also more time-consuming and messier for the examiner. Therefore, caloric testing is not recommended for provocative testing to determine the category of dizziness.
In all patients with dizziness or vestibular complaints, careful examination of the eyes, ears, cardiovascular system, nervous system, and vestibular system is indicated. Vestibular imbalance is indicated by nystagmus, past-pointing, and postural and gait abnormalities.
Because different types of nystagmus have different clinical implications, it is important to carefully characterize nystagmus both by its appearance and by any precipitating and inhibiting factors. For example, nystagmus may be characterized by the symmetry of the oscillations, whether the oscillations are linear or rotatory, and whether the oscillations are unidirectional or direction changing. Jerk nystagmus is identified by a clear slow phase drift in one direction and a quick corrective phase in the opposite direction. Jerk nystagmus is traditionally described by the direction of the quick phases, eg, "down beat" nystagmus. In contrast, pendular nystagmus is characterized by smooth sinusoidal oscillations of the eyes.
Precipitating factors for nystagmus may include specific eye and head positions. Pathologic nystagmus may be present in primary position (spontaneous nystagmus), with a change in eye position (gaze-evoked nystagmus), or with a change in head position (positional and positioning nystagmus). Spontaneous nystagmus is assessed by direct observation of the patient’s eyes while the patient is looking straight ahead either fixating on a target or with fixation removed. Gaze-evoked nystagmus is assessed similarly, with the patient fixating on targets 30 degrees to the right, left, up, and down. Extreme eye positions should be avoided because they can result in "end-point" nystagmus in normal individuals. Positioning nystagmus is assessed with the Dix-Hallpike positioning test (89).
An important inhibiting factor for peripheral vestibular nystagmus is fixation. While fixating, patients with peripheral vestibular nystagmus can use their visual pursuit system to counteract the nystagmus. In contrast, fixation does not suppress central vestibular nystagmus because patients with central vestibular disorders cannot utilize their pursuit system to suppress the nystagmus. Central vestibular and visual pursuit pathways are highly integrated, so central vestibular lesions damage both systems, thereby precluding inhibition by fixation. In order to visualize peripheral vestibular nystagmus, special techniques may be needed to suppress fixation. Ophthalmoscopy is a readily available way of preventing fixation when the nonviewed eye is covered. The direction of linear nystagmus when viewed with an ophthalmoscope is reversed from that observed by direct inspection of the eye, as (1) the axis of rotation of the eye is perpendicular to the line of sight; and (2) the retina lies behind the center of rotation to the eye whereas the cornea lies in front. Torsional nystagmus can also be detected with an ophthalmoscope by observing the vessels around the macula. The direction of torsional nystagmus is not reversed when viewed with an ophthalmoscope because the axis of rotation is parallel to the line of sight.
Peripheral vestibular nystagmus. Peripheral vestibular nystagmus is a mixed linear-rotatory jerk nystagmus that beats in a single direction away from a hypofunctioning labyrinth. With semicircular duct stimulation or dysfunction, eye movements occur in the plane of an affected semicircular duct. With all forms of peripheral vestibular nystagmus, nystagmus amplitude and frequency increases with gaze in the direction of the quick phases due to summation of tonic driving forces and elastic restoring forces both moving the eyes in the direction of the nystagmus slow phases. The presence of any of the following suggests a central cause for the nystagmus: (1) the nystagmus has a pendular appearance; (2) the nystagmus is purely rotatory or purely linear; (3) the nystagmus changes direction with gaze in different directions; (4) the nystagmus is not suppressed with fixation; (5) vertigo is mild or absent; (6) nausea is absent; and (7) there are central neurologic signs or symptoms. Despite these helpful rules, small cerebellar strokes or small demyelinating lesions of the cerebellum or cerebellar peduncles may mimic labyrinthine lesions clinically (91; 02). Therefore, particularly in the elderly, great care should be taken in excluding a central cause for acute vertigo, and central lesions should certainly be suspected if the clinical features are atypical (59; 146; 145; 131; 91).
The Dix-Hallpike positioning test. The Dix-Hallpike positioning test is used to precipitate vertigo in patients with episodic symptoms, especially when the symptoms appear to be related to either head position or head movements. The Dix-Hallpike positioning test is a test for positionally induced nystagmus, particularly that associated with benign paroxysmal positioning vertigo (89). The patient is instructed to stare off into space and avoid looking at any specific object during the procedure. The patient’s head is turned to one side, and then the patient is rapidly moved backward from a sitting to a head hanging position. Turning the head to one side during the maneuver places the ipsilateral posterior semicircular duct in a parasagittal plane; when the patient is subsequently moved backward, the movement is in the plane of that duct. The examiner maintains the patient in the head hanging position for approximately 1 minute and observes the patient’s eyes for nystagmus. Anticipation or the experience of vertigo may make patients anxious. Calm but firm reassurance from the examiner is often necessary to complete the maneuver.
Like peripheral spontaneous nystagmus, peripheral positioning nystagmus is a mixed linear-rotatory jerk nystagmus. Peripheral positional vestibular nystagmus generally beats upward and toward the under-most ear and has a latency of 1 to 45 seconds and a duration of less than 60 seconds. It lessens or disappears with repetition of the offending head positioning.
Central positional/positioning nystagmus. The presence of any of the following suggests a central cause for the positional/positioning nystagmus: (1) the nystagmus begins immediately on assuming the offending head position; (2) the nystagmus has a pendular appearance; (3) the nystagmus is purely rotatory or purely linear; (4) the nystagmus changes direction with gaze in different directions; (5) the nystagmus is not suppressed with fixation; (6) the nystagmus continues indefinitely with maintenance of the offending head position; (7) the nystagmus persists with repetition of the offending head positioning; (8) vertigo is mild or absent; (9) nausea is absent; or (10) there are central neurologic signs or symptoms. As with spontaneous vestibular nystagmus, great care should be taken in excluding a central cause for acute vertigo, particularly in the elderly. Central positional/positioning nystagmus and vertigo can occur with lesions near the fourth ventricle, the vestibular nuclei, and the vestibulocerebellum (14), including isolated cerebellar nodulus infarction (77; 133), isolated cerebellar tonsillar infarction (113), hemispheric cerebellar infarction (137), and cerebellar tumors (28; 118).
The head impulse test (HIT), or head thrust test of the vestibulo-ocular pathways. The head impulse test (HIT), or head thrust test, utilizes corrective saccades after single rapid head turns to help identify the side of vestibular dysfunction, particularly when spontaneous nystagmus is absent (57; 10; 147). In this test, the patient’s head is turned rapidly to one side by the examiner, while the patient attempts to maintain fixation on an object 6 feet or more away. Passive (rather than active self-induced) head impulses are necessary to detect a severe unilateral peripheral vestibulopathy (10). The examiner observes the patient for corrective saccades. The gaze of a patient with unilateral labyrinthine dysfunction shifts only when the head moves quickly toward the dysfunctional side; an oppositely directed compensatory saccade corrects the gaze error. Thus, leftward saccades following rapid rightward head movements indicate right vestibular dysfunction, whereas rightward saccades following rapid leftward head movements indicate left vestibular dysfunction. The head impulse test primarily assesses the high-frequency function of the vestibulo-ocular reflex (as opposed to the caloric test, which primarily assesses the low frequency function); the diagnostic utility of the head impulse test is generally improved with larger accelerations up to 6000 degrees per second because these larger accelerations increase the asymmetry of vestibulo-ocular reflex gains and elicit larger catch-up saccades in patients with unilateral vestibular lesions (147). However, clinicians must be cautious because covert saccades during head rotation occur more frequently with higher acceleration and may be easily missed; therefore, to avoid false-negative results, the bedside head impulse test should be repeated to improve sensitivity (147).
Lightweight, high-speed video-oculography (VOG) technology has been applied to measure eye movements (ie, VOG-HINTS) in patients with the acute vestibular syndrome presenting to nonspecialists in emergency room settings (109). This "eye ECG" approach has been likened to the use of electrocardiography (ECG) to diagnose myocardial infarction in patients presenting with acute chest pain (111; 109; 96).
Caloric testing. Caloric testing may also help determine the side of a peripheral vestibular lesion. Otoscopy must be performed prior to the test to ensure that the tympanic membrane is intact and that wax does not obstruct the external canal. The patient’s head is elevated 30 degrees from a supine position to bring the lateral semicircular duct into a vertical orientation. Cold or warm water is instilled in the external canal, and this induces convection currents in the endolymph of the lateral semicircular duct. Because of its ready availability, ice water is commonly used for bedside testing. Two to 10 mL of ice water are usually adequate. A normal response to caloric stimulation with ice water consists of tonic deviation of the eyes toward the side of instillation plus nystagmus with quick corrective phases in the direction opposite to the tonic deviation; warm water produces the opposite response. The onset is in 30 to 60 seconds, and the duration is usually 1 to 3 minutes. In comatose patients, only tonic deviation is observed. In labyrinthine or eighth nerve lesions, neither cold nor warm water will elicit a normal response on the affected side; this is called canal paresis. Greater than 20% asymmetry in duration or frequency between the two sides suggests an abnormality on the side of the lesser response. If the dysfunction is mild, quantitative testing with electronystagmography may be necessary to establish the finding. If the ocular response to caloric stimulation is consistently greater in one direction than another, there is a directional preponderance of the vestibular system. This may occur with both central and peripheral vestibular disorders and by itself is not localizing. Such directional preponderance is typically associated with spontaneous nystagmus.
Clinical assessment of the vestibulospinal pathways. Clinical disturbances of the vestibulospinal pathways are assessed with several tests, including past-pointing, stance, the Romberg test, and tandem gait with eyes closed.
When assessing a patient for past-pointing, the patient is asked to sit facing the examiner with index finger extended and pointing at, but not touching, the examiner’s extended finger. The patient is then asked to raise the arm to a vertical position with the index finger pointing at the ceiling and then return the arm to the initial position. This is repeated several times with the eyes closed. Consistent deviation of the arm to one side is past-pointing. If extralabyrinthine inputs are not minimized by keeping the eyes closed and the arm extended, visual or proprioceptive signals will permit accurate localization of the target even if vestibular function is impaired; for this reason, the standard finger-nose-finger test is not helpful in identifying past-pointing. In acute vestibular lesions, patients past-point toward the affected side; however, the test can be misleading because central nervous system compensation rapidly corrects the past-pointing and can produce a drift to the opposite side.
With acute unilateral vestibular lesions, patients have impaired postural control and may sway or fall toward the lesion. Although this is helpful diagnostically, the examiner must take great care when assessing stance and gait in patients with vestibular complaints because patients may suddenly fall and injure themselves. The examiner must provide adequate support for the patient to prevent falls and injuries. In patients who cannot maintain their stance without support when their eyes are open, it is unnecessary and potentially dangerous to proceed with the Romberg test or an unsupported assessment of gait.
In patients with vestibular lesions, the tendency to fall toward the lesion is accentuated when patients are prevented from using vision to compensate for the vestibular imbalance; this is the basis of the Romberg test (88). In the Romberg test, the patient is first asked to stand with eyes open and feet together. If the patient cannot maintain balance in this position, the stance is widened until this is possible. The patient is then asked to close his or her eyes. Patients with proprioceptive or vestibular dysfunction may be unable to maintain this position. Patients with unilateral dysfunction usually sway or fall toward the side of the lesion, particularly if the dysfunction is acute (88). Because of central nervous system compensation, the test is less sensitive to chronic unilateral vestibular dysfunction (88). As with past-pointing, overcompensation may result in falls toward the "good" side.
With eyes open, tandem walking may be impaired with acute vestibular lesions. It is, however, mainly a test of cerebellar function because vision compensates for chronic vestibular and proprioceptive dysfunction. A better test of vestibular function is tandem walking with eyes closed. When cerebellar and proprioceptive function is normal, imbalance during this test indicates vestibular dysfunction. However, the direction of falling does not reliably indicate the side of the lesion. The test is also difficult for normal elderly persons.
Additional diagnostic tests. In some cases, additional diagnostic tests will be required. These should be ordered selectively, depending on the type of dizziness and suspected underlying etiologies (85). Diagnostic studies that may be helpful in selected patients with vertigo (not attributable to benign paroxysmal positioning vertigo) include audiometry, electronystagmography, bithermal caloric testing, brainstem auditory evoked potentials, and cranial imaging (50; 07; 46; 56; 72; 53). In particular, a high percentage of patients with normal examinations and nonspecific vertigo suffer from peripheral vestibular dysfunction that can be documented with electronystagmography and rotatory chair testing (50; 07; 46). Prompt cranial imaging should be carefully considered in patients with a first attack of acute persistent vertigo presenting to an emergency room, especially in association with central signs or age over 60 years, to exclude rare cases of cerebellar infarction (19; 100). It must nevertheless be recognized that the diagnostic yield of cranial imaging for acute vertigo among patients presenting to an emergency room is generally low (75; 04; 53). In addition, there is a wide range of utilization of cranial neuroimaging for patients presenting with dizziness and vertigo, and imaging rates are not clearly associated with stroke diagnosis rates in such patients (77). When cranial neuroimaging is utilized, MRI is superior to CT for diagnosis of acute stroke in patients presenting with acute persistent vertigo to an emergency room (25; 68) and should include diffusion-weighted imaging (100; 68).
A pilot study has demonstrated that patient-initiated vestibular event monitoring is feasible and may facilitate rapid and accurate diagnosis of episodic vestibular disorders (152); by using miniature video-oculography goggles, adult neurology clinic patients were successfully taught to self-record spontaneous and positional nystagmus at home while symptomatic.
A constellation of clinical tests is more accurate than MR with diffusion-weighted imaging in identifying small strokes causing an isolated acute vestibular syndrome, especially as MRI with diffusion-weighted imaging is falsely negative in half of such patients up to 48 hours after onset (71; 27; 110; 109; 127).
“H.I.N.T.S.” or “HINTS” examination. The so-called “H.I.N.T.S.” or “HINTS” tripartite examination (ie, Head Impulse test, Nystagmus type, and Test-of-Skew) combines an assessment of the head impulse test (HIT), assessment of direction-changing horizontal nystagmus evoked by lateral gaze to the right and left, and assessment of vertical skew deviation by alternate cover testing (71; 27; 110; 109; 127; 126; 22; 139). The updated form of the HINTS examination approach, the “H.I.N.T.S. plus” or “HINTS plus” quadripartite examination, addresses some of the limitations of HINTS. The HINTS plus examination is simply the HINTS examination plus an assessment of bedside hearing by finger rub (110; 109; 127). In elderly patients with an isolated acute vestibular syndrome, a normal head impulse test, direction-changing horizontal gaze-evoked nystagmus, a skew deviation, or acute unilateral hearing loss suggests a central vestibular lesion, and specifically may indicate a vertebrobasilar stroke, whereas the absence of all of these strongly supports a peripheral basis, such as vestibular neuritis (127; 139). The following clinical features are consistent with vestibular neuritis: a predominantly horizontal direction-fixed nystagmus in all gaze positions, no skew deviation, absence of facial paresis, no acute unilateral deafness, normal otoscopy and mastoid examination, “positive” head impulse test with a unilateral abnormal vestibulo-ocular reflex on the side opposite the fast phase of a horizontal-rotary nystagmus, and ability to stand independently without holding onto another person or object (127). Patients with an isolated acute vestibular syndrome with noncentral “HINTS plus” findings and other appropriate clinical findings should be diagnosed at the bedside as vestibular neuritis, without neuroimaging, and managed accordingly.
The acronym mnemonic INFARCT--Impulse Negative (negative head impulse test); Fast phase Alternating (central pattern nystagmus); and Refixation during Cover Test (ie, skew deviation)—suggests a stroke or other central diagnosis (71). Typically, with labyrinthine infarction, the HINTS examination would not suggest a stroke or other central diagnosis: (1) the head impulse test will be abnormal with a visible refixation saccade with ipsilesional head impulses; (2) there will be a peripheral vestibular nystagmus, characterized by unidirectional horizontal-torsional jerk nystagmus with a contralesional fast phase that intensifies with fixation removed; and (3) there will be no skew deviation evident with alternate cover testing. In the absence of other information, this HINTS result would generally be interpreted as suggesting a relatively benign peripheral vestibular condition, like vestibular neuritis. However, acute cochleovestibular loss is not always due to a viral or inflammatory condition of the inner ear; it may result from ischemia or infarction of the cochlea and labyrinth (70).
Despite the numerous studies promoting HINTS or HINTS-plus, the individual elements of the triad or quartet of findings, respectively, may be misleading at times. Many patients with acute vestibular syndrome and negative head impulse test results are found to have peripheral, not central, lesions (92). That is, patients with acute vertigo who show spontaneous nystagmus with negative head impulse test findings do not always have central acute vestibulopathies and are found instead to have peripheral vestibulopathies from, for example, sudden sensorineural hearing loss with vertigo or the ictal period of Ménière disease (92). In one study, 155 patients were evaluated with acute vertigo and spontaneous nystagmus, of whom 30 did not show a loss of gain or catch-up saccades on both sides of the horizontal video head-impulse test; after thorough evaluation, including magnetic resonance imaging with diffusion-weighted imaging, 17 were found to have Ménière disease, 7 had sudden sensorineural hearing loss with vertigo, and only three had acute vascular stroke (92). Patients with peripheral vestibulopathy may have a skew deviation, suggesting (wrongly) that the lesion is central. In fact, up to a quarter of individuals with an acute unilateral vestibulopathy have a skew deviation (52; 81), although usually such skew deviations with peripheral vestibular disorders are of small magnitude (69; 44) and may be evident only with a Maddox rod test rather than with alternate cover testing (52). Consequently, some patients with labyrinthine infarction, including those with isolated labyrinthine infarction and those with a skew deviation might not be separately identified with the HINTS plus approach (112). Furthermore, when used in isolation by emergency physicians, the HINTS examination has not been shown to be sufficiently accurate to rule out a stroke (including labyrinthine infarction) in those presenting with an acute vestibular syndrome (114). This should serve to emphasize that the HINTS and HINTS-plus test batteries are only helpful heuristic guides that may help focus diagnostic evaluation and help target expensive tests (eg, magnetic resonance imaging) in an emergency department setting.
Special situations of high-risk conditions that should not be overlooked extend beyond HINTS and the discrimination of cerebral ischemia from relatively benign peripheral vestibulopathies in patients presenting with dizziness or vertigo. Such special considerations include infectious, demyelinating, and neoplastic disease presenting with vertigo (21; 55). Red flags of potential brain metastases in patients with cancer include vertigo in conjunction with any of the following: headache, ataxia, seizures, visual symptoms, speech impairment, altered mental status, or focal weakness (21).
STANDING test (or STAnDing test). The STANDING test is a structured diagnostic algorithm with sequential steps (138). The origin of the acronym is so strained and unhelpful as a mnemonic that it isn't worth articulating (others have also ignored the basis of the acronym and, hence, have referred to this as the STANDING test, rather than the STAnDing test).
• The presence of nystagmus is assessed with Frenzel goggles in the supine position after at least 5 minutes of rest. Frenzel goggles eliminate patient fixation (which can suppress nystagmus), and they combine significant magnification (ie, for the examiner) with a lighting system, all of which facilitate observation of nystagmus.
• If no spontaneous nystagmus is present in the main gaze positions, the presence of a positional nystagmus is assessed by first using the supine roll test (Pagnini-McClure maneuver) and then the Dix-Hallpike maneuver (36; 98; 115; 89). The presence of a positioning nystagmus with these maneuvers is considered to indicate benign paroxysmal positioning vertigo (BPPV).
• If spontaneous nystagmus is present and persistent in the supine position, the direction of the nystagmus is examined.
- Multidirectional nystagmus (eg, bidirectional gaze-evoked nystagmus) and pure vertical or torsional nystagmus are considered signs of central vertigo.
- If the nystagmus is unidirectional (ie, nystagmus beating in the same direction regardless of gaze direction and head position), a head impulse test (HIT) is performed. If a corrective “saccade” is present, the HIT is considered positive and indicates acute peripheral vertigo, whereas a negative HIT indicates central vertigo.
• Patients with neither spontaneous nor positional nystagmus are asked to stand, and gait is evaluated. Inability to maintain an upright stance without assistance is considered indicative of central disease.
In the initial study at the University of Firenze, Italy, the test performed reasonably well when applied in the emergency department of a tertiary care facility. The test had good interobserver agreement, with very high sensitivity (100%) and specificity (94%) for central vertigo. In addition, use of the diagnostic algorithm produced a significant reduction of neuroimaging and hospitalization rates.
In a prospective diagnostic study of patients with isolated vertigo and unsteadiness seen in a single emergency department at a tertiary care facility in Paris, France, emergency physicians performed both HINTS and STANDING assessments blinded to the attending physicians (and, hence, the service). ABCD2 scores were calculated retrospectively. The study involved 300 patients, of whom 62 (21%) had a central lesion on neuroimaging, including 49 strokes (79%). Of the 238 peripheral diagnoses, 159 (67%) were vestibulopathies, mainly benign paroxysmal positioning vertigo (40%). HINTS and STANDING tests achieved high sensitivities (97% and 94%, respectively) and negative predictive values (99% and 98%, respectively) for detecting central vertigo cases. The ABCD2 score failed to predict half of central vertigo cases. When used by emergency physicians, the HINTS and STANDING tests outperformed ABCD2 in identifying central causes of vertigo, admittedly a low bar given that the ABCD2 score was never intended for this purpose. More useful for diagnosing peripheral disorders, the STANDING algorithm is more specific than the HINTS test. Both the HINTS and STANDING tests can be useful tools for emergency physicians and can save both time and costs related to unnecessary neuroimaging use and hospitalization costs.
Consensus criteria of the Barany society for vascular vertigo. The following are diagnostic criteria for acute prolonged vascular vertigo and dizziness (78):
• Acute vertigo, dizziness, or unsteadiness lasting at least 24 hours. Other manifestations may include imbalance, oscillopsia, vegetative symptoms (eg, nausea and vomiting), and head motion intolerance.
• Imaging evidence of ischemia or hemorrhage in the brain or inner ear, which corresponds to the symptoms and signs. Because there is a high false-negative rate for imaging, serial radiological evaluation may be required to identify an acute lesion. Systematic clinical examination has a higher sensitivity during the acute phase than imaging.
• Not better accounted for by another disease or disorder.
The following are diagnostic criteria for probable acute prolonged vascular vertigo and dizziness (78):
• Acute vertigo, dizziness, or unsteadiness lasting at least 24 hours.
• At least one of the following:
- Focal central neurologic symptoms and signs (eg, hemiparesis, sensory loss, dysarthria, dysphagia, or severe truncal ataxia and postural instability).
- At least one component of central HINTS (eg, normal head impulse test, direction-changing gaze-evoked nystagmus, or pronounced skew deviation).
- Other central oculomotor abnormalities (eg, central nystagmus, impaired saccades, or impaired smooth pursuit).
- Increased risk of vascular events (eg, ABCD2 score of at least 4 or atrial fibrillation).
• Not better accounted for by another disease or disorder.
Special conditions causing vertigo. Autoimmune vertigo, with or without systemic autoimmune conditions, occurs when an abnormal immune response is directed against the inner ear (125). There may be functional or anatomic alterations with an inflammatory reaction that may be devastating for hearing and balance. Diagnosis is based either on clinical criteria or a positive response to steroids (125).
In vestibular paroxysmia, auditory or vestibular deficits are typically measurable by neurophysiological methods (16), although audiovestibular testing may be normal in a quarter of cases (06). MRI has very high sensitivity for detecting neurovascular compression of the eighth cranial nerve and good specificity (63; 06): the anterior inferior cerebellar artery is the compressing vessel in three quarters of cases, but the eighth nerve can also be compressed by the posterior inferior cerebellar artery, the vertebral artery, or a vein (06).
Although vertigo and basilar artery tortuosity rates increase with age, no significant relationship of basilar artery tortuosity with vertigo has been demonstrated (20). Patients with tortuosity have higher vertebral artery asymmetry/agenesis rates and increased basilar artery diameter than subjects without tortuosity, but no higher rate of vertigo (20).
• Drugs should be reviewed in all patients with dizziness, whether clearly vertiginous or not.
• Drugs associated with dizziness include alcohol and other central nervous system depressant medications (eg, benzodiazepines, barbiturates, phenothiazines), aminoglycoside antibiotics, anticonvulsants, antidepressant medications, antihypertensive medications, chemotherapeutic agents, loop diuretics (eg, furosemide), and salicylates.
• The elderly are particularly susceptible to drug ototoxicity.
• Vertigo (especially acute persistent vertigo) may be alleviated with vestibular sedatives.
• In patients with acute persistent vertigo from peripheral vestibular lesions, recovery occurs more rapidly and more completely when vestibular exercises are begun as soon as possible after the onset of symptoms.
• Treating patients who have acute vestibular neuritis with vestibular exercises is apparently as effective as treating them with corticosteroid therapy in terms of clinical, caloric, and otolith recovery; corticosteroid therapy seems to enhance earlier resolution of symptoms of acute vestibular neuritis, with no added benefit in long-term prognosis.
Drugs should be reviewed in all patients with dizziness, whether clearly vertiginous or not. Drugs associated with dizziness include alcohol and other central nervous system depressant medications (eg, benzodiazepines, barbiturates, phenothiazines), aminoglycoside antibiotics, anticonvulsants, antidepressant medications, antihypertensive medications, chemotherapeutic agents, loop diuretics (eg, furosemide), and salicylates. The elderly are particularly susceptible to drug ototoxicity because (1) they are more likely to receive ototoxic drugs; (2) they have less reserve (due to age-associated vestibular end-organ changes, pre-existing sensorineural hearing loss, and previous treatment with ototoxic drugs); (3) they are more likely to have impaired renal function. Alcohol can produce a positional vertigo syndrome (ie, positional alcohol nystagmus) because the alcohol can diffuse into the labyrinth and change the specific gravity of the rotation-transducing organs (ie, the cupulae of the semicircular ducts). Aminoglycosides can produce irreversible damage to labyrinthine hair cells, with resulting sensory disequilibrium or (if somewhat asymmetric) vertigo, along with oscillopsia, hearing loss, and tinnitus. Similar clinical pictures can occur with antimalarial agents, cisplatinum, ethacrynic acid, furosemide, minocycline, and salicylates. The dysfunction is usually reversible with furosemide, minocycline, and salicylates.
Vertigo (especially acute persistent vertigo) may be alleviated with vestibular sedatives (85; 128). Some types of vertigo may also be amenable to specific curative therapies, most notably with canalith repositioning maneuvers for benign paroxysmal positioning vertigo (17; 89; 103). Although surgery was previously employed for benign paroxysmal positioning vertigo, surgery is now rarely necessary except in exceptional refractory cases (94). Vertigo associated with migraine may respond to abortive and prophylactic antimigraine treatments (148; 122; 61). Other forms of episodic vertigo (such as Ménière syndrome and vestibular paroxysmia) may benefit from pharmacological or surgical therapies (16; 05; 63; 60; 85; 18). In patients with vestibular paroxysmia, carbamazepine and oxcarbazepine are the most effective drugs and are often dramatically effective even at low dosages (16; 63; 18). In one study, carbamazepine or oxcarbazepine reduced attack frequency to 10% of baseline, attack intensity to 15%, and attack duration to 11% (63). Second-line pharmacological therapies for vestibular paroxysmia include lamotrigine, phenytoin, gabapentin, topiramate, or baclofen (18). In medically intractable cases of vestibular paroxysmia, retromastoid craniotomy and microvascular decompression can be considered (16; 18). Corticosteroids are the most effective and accepted treatment for autoimmune vertigo (125).
In patients with acute persistent vertigo from peripheral vestibular lesions, recovery occurs more rapidly and more completely when vestibular exercises are begun as soon as possible after the onset of symptoms (149; 30; 31; 140; 123). Data from randomized controlled trials are limited, particularly in the middle-aged and elderly population (97). However, available studies showed positive results in favor of vestibular rehabilitation therapy in postural control, functional capacity, and quality of life. However, because of methodological limitations and interstudy differences among available studies, the optimal protocol and timing of interventions are as yet undefined.
Treating patients who have acute vestibular neuritis with vestibular exercises is apparently as effective as treating them with corticosteroid therapy in terms of clinical, caloric, and otolith recovery (51); corticosteroid therapy seems to enhance earlier resolution of symptoms of acute vestibular neuritis, with no added benefit in long-term prognosis (51).
A number of variations of vestibular exercises have been advocated, some more complex than others, and evidence is insufficient to support one form over another (140). Typically, eye and head movements are begun as soon as possible after the acute vertigo and autonomic symptoms subside; then, more complicated exercises involving head movements, bending, standing, and moving about are gradually introduced as the patient improves. Patients can begin while still in bed by repetitively moving the eyes up and down and then side-to-side at first slowly, then quickly. Then patients repetitively move their head forward and backward and side-to-side at first slowly, then quickly. Progression is next to performing exercises while sitting: eye and head movements as described above, then rotating head and shoulders at first slowly, then quickly, and then bending forward and picking up objects from the floor. Next, patients practice changing from sitting to standing, at first with eyes open and then with eyes closed. While standing, eye and head movements are practiced. Patients then practice moving about: turning around; walking across a room at first with eyes open and then closed; standing on one foot, at first with eyes open and then closed; climbing up and down steps with eyes open; and playing games involving stooping, stretching, and aiming (eg, shuffleboard or bowling). The exercises should be performed for at least 5 minutes several times per day. Specific head positions and movements that precipitate vertigo should be sought and repetitively performed to facilitate vestibular compensation. Antivertiginous medications can be used during the exercises to help control both the vertigo and the autonomic symptoms. Although there are theoretical reasons to imagine that vestibular sedatives may limit the efficacy of vestibular exercises, there is no solid evidence that such medications affect either the rate or degree of vestibular compensation. Instrumental rehabilitation training on a moving platform can also be effective for treating vestibular balance disorders and can result in improved control of balance and greater independence in activities of daily living (31), although such treatment often is not readily available.
In a given patient, it is often difficult to predict what drug or combination of drugs will be most effective in alleviating the symptoms of acute persistent vertigo. The drug or drug combination is empirically chosen based on the known effects of each drug and on the course and severity of the patient’s symptoms. Severe forms of acute persistent vertigo are especially distressing, particularly when accompanied by nausea and vomiting; antivertiginous medications with both sedative and antiemetic effects are helpful in these situations (eg, promethazine, droperidol, dimenhydrinate). Chronic recurrent vertigo is less distressing and interferes less with daily activities; agents with less sedating properties will help patients carry on with their normal routine (eg, meclizine, trimethobenzamide). Agents that commonly cause confusion because of central nervous system depressant or anticholinergic properties should be utilized carefully or avoided in the elderly (eg, diazepam, phenobarbital, dimenhydrinate, meclizine). Also, parenterally administered drugs that may produce hypotension or respiratory depression (eg, diazepam, droperidol, phenobarbital, prochlorperazine, or trimethobenzamide administered either intramuscularly or intravenously as appropriate) should generally be used only in a hospital setting.
Surgery is needed to manage vertigo in only a small percentage of patients, and even in an institutional vertigo clinic, only 1% is managed surgically (119). Useful disease-modifying surgical treatments in highly selected patients include perilymphatic fistula repair and microvascular decompression of the vestibular nerve. Labyrinth-destructive procedures include transmastoid labyrinthectomy and labyrinthectomy with vestibular nerve section (26). Vestibular neurectomy for intractable vertigo is generally well tolerated and can effectively relieve intractable vertigo due to, for example, Ménière disease, uncompensated vestibular neuritis in two patients, and other vestibular neuropathy (26). Patients with mass lesions of the labyrinth or internal auditory canal (eg, vestibular schwannoma) may benefit from combined disease-modifying and destructive procedures (eg, translabyrinthine excision).
All contributors‘ financial relationships have been reviewed and mitigated to ensure that this and every other article is free from commercial bias.
All contributors‘ financial relationships have been reviewed and mitigated to ensure that this and every other article is free from commercial bias.
All contributors‘ financial relationships have been reviewed and mitigated to ensure that this and every other article is free from commercial bias.
Douglas J Lanska MD FAAN MS MSPH
Dr. Lanska of the University of Wisconsin School of Medicine and Public Health and the Medical College of Wisconsin has no relevant financial relationships to disclose.See Profile
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