Morvan syndrome and related disorders associated with CASPR2 antibodies
Jan. 18, 2022
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In this article, the authors provide an overview of memory loss and its most common presentations in the clinical setting (mild cognitive impairment, Alzheimer disease, vascular dementia, dementia with Lewy bodies, Wernicke-Korsakoff syndrome, and chronic traumatic encephalopathy). Risk factors for mild cognitive impairment are reviewed, along with lifestyle changes that have been suggested to slow progression from mild cognitive impairment to dementia.
• Early-onset Alzheimer disease patients are more likely to be younger, male, and have atrophy in both parietal lobes, rather than in medial temporal lobes, as is seen in late-onset Alzheimer disease. They also have more problems with language, attention, visuospatial function, and executive tasks, compared to the memory loss seen in late-onset typical or limbic-predominant Alzheimer patients.
• Chronic traumatic encephalopathy causes early memory loss in boxers, football players, and war veterans. The neurofibrillary tangles and extracellular plaques in the brains of these patients at autopsy are similar to those seen in the brains of Alzheimer disease patients, but chronic traumatic encephalopathy is defined pathologically by an abnormal accumulation of tau protein that is different from the pattern seen in Alzheimer disease. The duration of football played bears a strong dose-response relationship to the severity of neuropathology in these patients.
• There has been a recent cluster of young people (mean age = 35 years) who developed anterograde amnesia after waking up after acute episodes of substance abuse (62% involving heroin or other opiates). MRI in several of these patients showed ischemic changes in both hippocampi.
• Longitudinal studies in older adults have demonstrated that a higher level of total daily physical activity is associated with reduced risk of cognitive decline and Alzheimer disease. Animal studies have shown that both exercise and sleep accelerate glymphatic clearance of beta amyloid from the brain and reduce the accumulation of amyloid plaques.
• Several longitudinal cohort studies have followed biomarker profiles of brain amyloid, brain tau, and neurodegeneration in cognitively normal older adults over a mean of seven years and have found that abnormal markers of both amyloid and tau are necessary for the occurrence of the accelerated neurodegeneration and memory loss that precedes Alzheimer disease. Subtle cognitive changes can be measured before or concurrently with early Alzheimer biomarker changes before signs of mild cognitive impairment appear.
Wernicke-Korsakoff syndrome. In 1881, Carl Wernicke described two male alcoholics and one female with persistent vomiting who presented with acute confusion and ataxia (all three died by the end of two weeks). In 1887, Sergei Korsakoff reported 20 patients with either alcoholism or vomiting who developed chronic memory loss and polyneuropathy. We now use the term “Wernicke-Korsakoff syndrome” to describe this biphasic illness, where the acute phase is called Wernicke encephalopathy, and the chronic disorder is known as Korsakoff syndrome (145). MRI signs of Wernicke-Korsakoff syndrome include the chronic signs of shrunken mammillary bodies and acute signs of hyperintense T2 signal in thalami and periaqueductal grey (154).
Vascular dementia. In 1894, Otto Binswanger wrote about eight patients who were middle-aged when they developed acute confusion, then chronic memory loss, focal neurologic signs, gait disorder, and functional impairment. Their memory disorder fluctuated over time, but at autopsy all of them showed evidence of diffuse subcortical demyelination with sparing of cortical neurons. Hypertension and diabetes are the most important risk factors for vascular dementia, especially the subtype known as Binswanger disease (62; 110).
Alzheimer disease. In 1906, Alois Alzheimer described two women who experienced the insidious onset of memory problems in their 50s. Their memory disorders steadily progressed, and when they died several years later, Dr. Alzheimer found microscopic changes (tangles and plaques) in and around cortical neurons. Genetic analysis from one of these first patients identified a point mutation in the presenilin 1 gene, leading to a Phe176Leu amino acid substitution (111). This could explain the early memory loss in this first case.
In 2007, research criteria were developed to capture Alzheimer disease patients at their very earliest stage when there is a problem with episodic memory, but before full-blown dementia appears. These criteria stipulate that in addition to memory loss, there must be an abnormality in at least 1 or more biomarker, including thinning of the entorhinal cortex (MRI), amyloid or tau accumulation (PET), and/or an abnormality in CSF protein (beta-amyloid or tau) (37).
Frontotemporal dementia. In the late 19th century, Arnold Pick described the first cases of frontotemporal dementia (170). Now, frontotemporal dementia refers to a diverse group of disorders that involve atrophy of specific areas of the frontal or temporal lobes, or both (brain MRI and neuropsychological testing are both needed for an accurate diagnosis). The presenting features are behavioral changes (behavioral variant), language problems (progressive nonfluent aphasia, semantic dementia), or behavioral changes associated with motor neuron disease rather than memory loss.
Dementia with Lewy bodies. Lennox and others described diffuse Lewy body disease as being different from Alzheimer disease in that it has a more fluctuating clinical course, extrapyramidal signs, well-formed visual hallucinations, and increased sensitivity to neuroleptic drugs (92). An autopsy study from one large dementia clinic in North America showed that dementia with Lewy bodies accounted for at least 20% of the total number of brains, although many of these brains showed features of Lewy body disease and Alzheimer pathology (14). Besides dementia, dementia with Lewy body patients must have at least 2 of these 4 clinical features for a probable diagnosis: (a) visual hallucinations, (b) fluctuating levels of alertness, (c) signs of parkinsonism, or (d) REM sleep disorder (104).
Mild cognitive impairment. In 1999, Petersen and others described mild cognitive impairment as being a transitional state between normal aging and dementia (127). Symptoms of mild cognitive impairment can vary depending on whether they are preclinical manifestations of Alzheimer disease (memory complaints), vascular dementia (executive dysfunction), dementia with Lewy bodies (fluctuations in cognition), or other dementias (65; 108). Duff and others showed that nearly 40% of those genetically at risk for Huntington disease meet criteria for mild cognitive impairment (38), just as about 40% of Parkinson patients have mild cognitive impairment (82). In 2019, the AAN Quality Improvement Committee defined someone with mild cognitive impairment as having acquired objective cognitive deficits that were insufficiently severe to affect most usual daily activities (43).
Chronic traumatic encephalopathy. In 2009, McKee and others described a condition in football players and war veterans that is now known as chronic traumatic encephalopathy (103). In these brains, there are deposits of neurofibrillary tangles of tau protein and extracellular amyloid plaques that are similar to those seen in Alzheimer disease. These brains also look similar to those of boxers (dementia pugilistica). Jordon and others earlier showed that the risk of dementia was higher in victims of sports injuries if they had one or two of the apolipoprotein E epsilon 4 alleles (72).
Subjective cognitive decline. When patients complain of memory loss, but have unimpaired performance on cognitive tests, we say that they have subjective cognitive decline (142). The newest criteria for subjective cognitive decline have been reported by the Subjective Cognitive Decline Working Group (68). Stage 3 of preclinical Alzheimer disease, for example, is defined by biomarker evidence for Alzheimer disease plus subjective cognitive decline without the objective cognitive impairment that is seen with mild cognitive impairment. One study provided evidence that subtle cognitive decline can sometimes precede the accumulation of beta-amyloid or the thinning of the entorhinal cortex in cases of preclinical Alzheimer disease (159).
When we assess memory at the bedside, we are examining four subtypes of memory, according to the following table:
Synonyms or conceptually similar terms
Primary memory or registration
Semantic or long-term memory
Method of bedside assessment
Auditory attention span for up to 7 digits
Digits forward, serial subtraction
Memory for 3 items after 3 minutes
History of public events, or vocabulary
Immediate memory (primary memory or registration). Immediate memory is tested by asking patients to repeat word lists or number lists. It involves short-term storage for only a few seconds. Memory storage in this system has limited capacity and is highly susceptible to interference. The quantity of information that a normal person can retrieve in immediate memory is limited to about six or seven digits. Patients with impaired immediate memory are acutely confused, or they have moderate to severe dementia.
Working memory. Working memory is a system for temporarily storing the information needed to carry out a cognitive task. It is related to immediate memory, but it involves the additional task of concurrently manipulating information while recalling it. Forward digit span is a prototypical method to assess working memory. The average memory span for a random number of digits in normal adults is about seven digits (the length of a phone number).
Recent memory. Recent memory is tested at the bedside when we ask patients to remember three items after a three-minute distraction task. Disorders of recent memory include classic examples such as Wernicke-Korsakoff syndrome, Alzheimer disease, and transient global amnesia. Deficits in recent memory are due to an inability to learn new information and to retrieve it after a delay of a few minutes. The 24-item Grober and Buschke test was used in one study to compare recent and delayed recall performance of Alzheimer patients with those who had other types of dementia (20). Alzheimer patients did poorly on both free and cued recall, suggesting both encoding and storage problems. The free recall score from the Free and Cued Selective Reminding Test has been shown to be better than the Logical Memory-Immediate Recall Test at identifying older adults with memory complaints who will go on to develop Alzheimer disease over the next 2 to 4 years (31).
Remote memory (semantic memory or long-term memory). Remote memory is assessed by asking patients about important public events that took place decades earlier (eg, “what happened in November of 1963? September of 2001?”). Semantic memory also includes things that are common knowledge (“What is the capital of England? Capital of France?”). If the patient is an older veteran, he can be asked, “Who were we fighting in World War II?” In a large prospective study, semantic memories were shown to be in particular decline during the five to six years just prior to the diagnosis of Alzheimer disease (174). Alzheimer patients with small social networks were the ones most likely to lose semantic memories in the early stages of the disease (11).
Delayed recall. Neuropsychologists have used the Rey Complex Figure Test (RCFT) to assess delayed recall in patients with subcortical vascular dementia (67). The Selective Reminding Test has been applied to comparisons of delayed recall in progressive supranuclear palsy and Parkinson disease (35). The 24-item Grober and Buschke test was used to assess free and cued recall in patients with Alzheimer disease and other types of dementia (20). Delayed (cued) recall was better in vascular and frontotemporal dementia than in Alzheimer disease, suggesting a problem with retrieval, rather than a problem with encoding.
Verbal memory. The Buschke Selective Reminding Test (BSRT) has been used by neuropsychologists to assess verbal memory in those who have dementia with Lewy bodies and Alzheimer disease (116). The California Verbal Learning Test-SF was applied to the evaluation of verbal episodic memory in a study comparing dementia with Lewy body patients with other synucleinopathies (75). The Rey Auditory Verbal Learning Test (RAVLT), a multi-trial list learning and memory test, was utilized to assess verbal episodic memory in patients with mild cognitive impairment and Alzheimer disease (155).
Visual and spatial memory. The Benton Visual Retention Test (BVRT) has been applied to studies of visual memory in those with dementia with Lewy bodies and Alzheimer disease (116). The Rey-Osterrieth complex figure test with a 10-minute free recall delay has been used to assess nonverbal episodic memory in dementia with Lewy bodies, Parkinson disease, and multiple system atrophy (75). In early phases of Alzheimer disease, patients are known to lose navigational skills and spatial memory. A study examined early Alzheimer patients in virtual environments while they were being tested in fMRI or PET scanners to determine that early brain changes were occurring in the right anterior hippocampus (16).
Global cognitive assessments. It is critical that every new patient with a memory complaint has at least one global assessment of cognitive function in the chart, whether the initial diagnosis is mild cognitive impairment or dementia (43; 144). The Mini-Mental State Examination (MMSE) is a 30-question test used in clinic settings as a screening tool for older patients who are suspected of having memory problems. In a large Cochrane Systematic Review, the accuracy of the MMSE for assisting in the diagnosis of dementia was greatest (sensitivity 0.85; specificity 0.90) if the chosen cut-point was 24 or less (26). Another 30-question global assessment measure is the Montreal Cognitive Assessment (MoCA), which has been shown to be comparable to the MMSE in documenting mild cognitive impairment (sensitivity 0.89; specificity 0.75) (161). Because the MoCA has more measures of executive function compared to the MMSE, it is preferred by those who manage patients with vascular dementia (179) and many who manage patients with Parkinson disease and other movement disorders. The Saint Louis University Mental Status Examination (SLUMS) is also effective in identifying patients with MCI and dementia (157). The paper Self-administered Gerocognitive Examination (SAGE) is a valid and reliable cognitive assessment tool that can assist in identifying patients with mild cognitive impairment or early dementia. A new tablet-based version (eSAGE) has shown a strong association with the validated paper SAGE and a neuropsychological battery (141). Both have the advantage of self-administration, brevity, and four interchangeable forms.
Mild cognitive impairment. This condition progresses to dementia at a rate of about 10% to 17% per year (123; 86; 125). Those who have amnestic mild cognitive impairment (prodromal Alzheimer disease) or prodromal vascular dementia (those who have had at least one stroke) make the conversion to dementia at an even more rapid rate of 17% to 20% per year. The best predictors of conversion from amnestic mild cognitive impairment to Alzheimer disease were the results of baseline FDG-PET and episodic memory test scores (86). Other predictors of conversion to mild cognitive impairment or dementia are lower average sleep efficiency or greater variability in sleep time (33). Longitudinal studies with the Framingham cohort also showed that midlife systolic hypertension is a risk factor for conversion to incident dementia (HR 1.57; 95% CI 1.05-2.35) (102).
Alzheimer disease. Longitudinal studies of Alzheimer disease have shown that it follows three phases in many patients: a gradual onset over the first two to three years, then a slow progression over the next 5 to 10 years, followed by a rapid decline over the last 1 to 2 years. This pattern persists, even with the medications that slow the progression of symptoms (133). Those Alzheimer patients who have all their vascular risk factors treated decline less rapidly than those who do not manage their hypertension, diabetes, or hyperlipidemia (32). There are 3 subtypes of Alzheimer disease besides the typical presentation, including the early-onset subtype (17%), which is characterized by male predominance, sparing of the hippocampus, APOE-e4 noncarrier status, and a nonamnestic syndrome (41). Another subtype is the limbic predominant (21%), where there are more women than men, more cases of hippocampal sclerosis, more APOE-e4 carriers, and usually an amnesia presentation.
Vascular dementia. Patients with vascular dementia have shorter lifespans than those with Alzheimer disease because of earlier gait problems, more frequent falls, and more deadly vascular comorbidities, such as stroke, peripheral vascular disease, congestive heart failure, and myocardial infarction (62). The Rush Alzheimer Disease Center Study showed that there was a synergistic interaction between subcortical infarcts and Alzheimer disease because infarcts did not simply add to the cognitive effects of Alzheimer disease, but multiplied the effects (143). Incidental lacunes on MRI predict a steeper rate of decline in executive function and psychomotor speed (70). In a study of 142 subcortical vascular cognitive impairment patients, the early-onset group was more likely than the late-onset group to show signs of frontal-executive impairment (67). There were more lacunes in the deep white matter of the frontal lobes in the early-onset patients.
Dementia with Lewy bodies. A longitudinal clinical study compared dementia with Lewy body disease and Alzheimer disease and found similar rates of cognitive decline within the first few years (61). A pathological study showed that those with Lewy body disease had shorter disease duration from symptom onset to death, compared to those with Alzheimer disease (49). Shorter disease duration was particularly noted in men, in those who had later age at onset, and in those who had the diffuse neocortical Lewy body subtype; the severity of associated Alzheimer plaques or tangles did not appear to influence disease duration (49). Several autopsy studies have reported that 75% to 80% of dementia with Lew body brains show signs of having concomitant Alzheimer changes in variable amounts, explaining the wide range of disease severity and life expectations (63).
Frontotemporal dementia. The onset of the behavioral variant of frontotemporal dementia is usually before the age of 65, so this makes it the second most common form of pre-senile dementia (40; 25). The most rapidly progressing subtype of frontotemporal dementia is associated with motor neuron disease, where death occurs within three to five years of symptom onset (170). In contrast, those with semantic dementia can survive for 10 years or more (mean survival is 9.1 years) (25). As the slower frontotemporal dementias progress (behavioral variant, progressive nonfluent aphasia, and semantic dementia), they become more difficult to distinguish from each other, and they acquire features that are common to all dementia patients (wandering, intrusive behaviors, apathy, incontinence, dysphagia, etc.) (170).
Wernicke-Korsakoff syndrome. Some of the symptoms of Wernicke-Korsakoff syndrome respond over days to weeks to intravenous thiamine replacement therapy (nystagmus, dysarthria, and ataxia, for example), but the memory disorder is likely to persist over several months to years, even when patients take daily oral replacement therapy (145; 12).
A 64-year-old man was admitted because of memory loss, dysarthria, and ataxia for the past two months. He had a 20-year history of alcoholism, drinking one to two shots of hard liquor and six beers each day. On examination, he looked his stated age but was unkempt. He was alert and fully oriented; he was able to name, repeat, and follow commands. His speech was moderately dysarthric. He could register three items after one trial, but he could not recall any of these three items at three minutes. Nystagmus was noted on right lateral gaze, but there was no evidence of ophthalmoplegia or gaze palsy. He had dysmetria on heel-to-shin testing in both legs but no dysmetria on the finger-nose-finger test. He had decreased appreciation for pin sensation in both legs in a stocking distribution. Reflexes were hypoactive throughout, and his toes were downgoing to plantar stimulation. Postural instability was noted in the Romberg position with eyes open. Gait was wide-based and ataxic. After one day of intravenous thiamine, this patient’s nystagmus disappeared. After a week of daily intravenous thiamine replacement therapy, the ataxia and dysarthria improved. Even with continued daily oral thiamine replacement as an outpatient, this patient’s recent memory problems and neuropathy persisted for several years.
Comment. This is a typical story for Wernicke-Korsakoff syndrome, which results from a deficiency in vitamin B1 (thiamine). In developed countries, most cases of this disorder are related to the misuse of alcohol, but several cases have been attributed to gastric bypass surgery, anorexia, hyperemesis, intestinal obstruction, AIDS, and total parenteral nutrition. Genetic defects are likely to combine with dietary factors to explain why only a fraction of those with chronic alcoholism acquire this disease (145).
Hippocampal formation. The hippocampi and mesial temporal lobes are the regions of the brain most consistently responsible for consolidating recent memories for dates, faces, and events. The most famous patient with memory loss was H. M., who at the age of 27 developed sudden memory loss after a surgical procedure where both his hippocampi were removed for intractable seizures (03; 100). After the procedure, H. M. had marked loss of recent memories, but his semantic (long-term) memories for the years preceding the event were preserved. He had dampened expression of emotion and lack of initiative, which may relate to the removal of both the anterior hippocampus and the amygdala (03).
Hippocampal volume loss is a predictor for the development of amnestic mild cognitive impairment among cognitively normal older adults (44; 74). Noh and colleagues showed that in early-onset Alzheimer disease patients, the first atrophic changes were in the parietal lobes, consistent with the early changes in language and visuospatial problems. The late-onset Alzheimer cases in this series had more memory complaints, consistent with either diffuse cortical or bilateral hippocampal atrophy (117; 41). In amnestic Alzheimer patients, there was reduced hippocampal-to-cortical connectivity, as measured by resting-state functional MRI. This was in contrast to aphasic Alzheimer patients (primary progressive aphasia), where there was reduced connectivity from the left inferior frontal gyrus to the cortex (98).
Reduced volume in the right hippocampus is seen in patients who have the subjective cognitive impairment that precedes mild cognitive impairment (142). Jack and colleagues reported that hippocampal atrophy begins to slowly progress in normal controls after the age of 30, paralleling the slow deterioration of memory function in middle-aged individuals (66). They showed that both memory decline and hippocampal atrophy precede significant changes in amyloid PET, making it likely that non-Alzheimer processes are responsible for the functional decline of middle age.
The anterograde amnesia that develops after cardiopulmonary arrest is due to bilateral lesions in the hippocampi (29). Herpes simplex encephalitis can cause neuronal death in the hippocampi and mesial temporal lobes (76; 175). Football players with and without concussion have smaller hippocampal volumes, compared to age-matched healthy controls (148). Players with concussion have smaller hippocampal volumes than those without concussion. A series of 14 young to middle-aged patients with substance abuse (ages 19 to 52) presented to the emergency department with confusion or unconsciousness. When they woke up, they had anterograde amnesia (07). Their MRI scans showed signs of bilateral hippocampal ischemia.
Thalami and mamillary bodies. Brains of Wernicke-Korsakoff patients show areas of hemorrhagic necrosis or atrophy in the dorsal medial nuclei of the thalamus and in the mamillary bodies (145; 154). There are links between the hippocampal formations and these midline structures, explaining why anterograde amnesia can result from bilateral thalamic infarcts (50; 97). In a study of a patient with multiple sclerosis, an isolated gadolinium-enhancing plaque in the anterior thalamus was associated with loss of memory, personality change, and hypersomnolence (71).
Cerebral cortex. The nucleus basalis of Meynert is the major source of cholinergic innervation for the cerebral cortex and is significantly diminished in Alzheimer disease, Parkinson disease, and Wernicke-Korsakoff syndrome (04). One MRI study showed as much atrophy in the nucleus basalis of Meynert (20% to 25%) in patients with dementia with Lewy bodies as in those with Alzheimer disease (53). Semantic (long-term) memory is stored diffusely in the cerebral cortex (83). The earliest MRI spin-labeling changes (hypoperfusion) to be seen in Alzheimer brains are those in the posterior cingulate cortex (69). The cerebral cortex can be markedly impaired in patients who develop hypoxic encephalopathy after cardiac arrest (02). In Alzheimer disease, the magnitude of thinning of the cerebral cortex correlates well with the severity of both cognitive and functional impairment (06). In early-onset Alzheimer disease patients, the visuospatial and language problems seen in the early stages can be associated with bilateral atrophy of the parietal association cortices (117; 41).
Frontostriatal system. In early stages of various extrapyramidal diseases, such as progressive supranuclear palsy, short-term memory is normal, but memory retrieval is a problem. This is due to dysfunction in the frontostriatal system, rather than in the hippocampus. The Selective Reminding Test can be used to demonstrate memory retrieval problems in progressive supranuclear palsy, Parkinson disease, and Huntington disease; on the other hand, Alzheimer disease patients have poor recall, even after being given a cue (131; 35). In cases of subcortical vascular cognitive impairment, delayed recall (as measured by the Rey Complex Figure Test) correlates with the number of lacunes. Frontal lobe dysfunction (as measured by the Stroop color reading test) also correlates with lacune number in these patients (67).
Cerebellum. Although the cerebrum and hippocampus are important for consolidating and storing declarative memories, the cerebellum is key for storing procedural memories, such as riding a bicycle or playing the piano (120; 05). The combined activation of two synaptic inputs to the Purkinje cells depresses the transmission efficacy of those neurons. This long-term depression is thought to be the cellular basis for motor learning.
Alzheimer disease. Extracellular accumulation (plaques) of beta-amyloid and intracellular accumulation (tangles) of tau are thought to be the neuropathologic hallmarks of Alzheimer disease (37; 44; 149). The accumulation of these two proteins is thought to cause memory problems by disrupting normal synaptic function. As Alzheimer disease pathology increases, CSF markers (high levels of tau and low levels of A-beta 42) have been shown to be good predictors of the conversion from amnestic mild cognitive impairment to Alzheimer disease (44; 86). Longitudinal prediction of dementia of the Alzheimer type has also been associated with the hypometabolism on FDG-PET, APOE genotype (e4 allele), smaller whole brain volumes, lower hippocampal volume, reduced thickness of the parietal cortex, and higher cerebrospinal fluid tau levels (86; 136; 66; 45). The work of Soldan and colleagues pooled data from 4 cohort studies where changes in CSF amyloid, brain tau, and neurodegeneration were followed in 814 cognitively normal older adults over seven years (151). The results were consistent with the hypothesis that both reduced CSF amyloid and elevated tau were necessary to observe significant neurodegeneration and cognitive decline over time.
Mild cognitive impairment. In several studies in which amyloid was detected in brains with PET by using the tracer Pittsburgh compound B (PIB), mild cognitive impairment patients had more rapid progression to Alzheimer disease, compared to cases where there was no amyloid (178). Mild cognitive impairment patients who have large areas of connectivity on fMRI during memory tasks show slower progression to Alzheimer disease than those who have small areas of connectivity (129). The first biomarker to become abnormal in most mild cognitive impairment patients is brain A-beta 42 (measured by the PIB scan), and the next is temporoparietal hypometabolism (assessed with FDG-PET), followed by the presence of hippocampal atrophy (MRI scan) (44; 86; 132).
Wernicke-Korsakoff syndrome. Thiamine deficiency is the cause of the hemorrhagic necrosis and brain atrophy in Wernicke-Korsakoff syndrome (145; 154). These lesions occur in the dorsal medial nuclei of the thalamus, fornix, mamillary bodies, and the periaqueductal gray matter, all of which have relatively high metabolic rates. If there is not enough thiamine for the pivotal enzyme pyruvate dehydrogenase, then lactate is produced from glucose, instead of ATP. Navarro and colleagues have used nuclear magnetic spectroscopy to demonstrate lactate accumulation in the brains of patients with Wernicke encephalopathy (113).
Vascular dementia. This is a heterogeneous group of cognitive disorders that results from either small vessel disease, large vessel disease, cardioembolic infarction, or some combination of these three (110; 48; 30). The most common form of vascular cognitive impairment is mixed vascular cognitive impairment/Alzheimer disease, where there are signs of both Alzheimer disease and vascular dementia (14; 89; 143; 180; 30; 67). The most common “pure” vascular dementia is Binswanger disease, or subcortical vascular dementia, which is associated with chronic hypertension, subcortical arteriosclerosis, hypoperfusion, and subsequent bilateral demyelination of subcortical white matter (62; 91; 30). Pure vascular dementia is related to severe white matter intensities on MRI, reduced fractional anisotropy, younger age, greater number of lacunes, and lesser amount of medial temporal atrophy (81; 179). Early-onset subcortical vascular cognitive impairment patients in one study had more deep frontal lacunes, whereas the late-onset cases had more cortical and hippocampal atrophy on MRI and more amyloid accumulation on Pittsburgh compound B-PET scans (67).
Dementia with Lewy bodies. These patients have a cholinergic deficiency in the basal forebrain and other brain areas that is often more severe than that seen in Alzheimer disease (160; 171). This explains why Lewy body patients can have a more dramatic early benefit with cholinesterase inhibitors than is noted in most Alzheimer patients. Volumetric MRI studies showed the volume of the nucleus basalis of Meynert to be reduced by 20% to 25% in dementia with Lewy body patients, which was comparable to the volume loss seen in the Alzheimer cohort in one study (53). As in Parkinson disease, another condition of misfolded alpha-synuclein proteins, Lewy bodies accumulate in the neurons of the substantia nigra, but in dementia with Lewy bodies, they also accumulate in the cortex. Reduced levels of alpha-synuclein in the CSF of Lewy body patients probably reflect the accumulation of alpha-synuclein in the brain (78). Dementia with Lewy bodies and its core features aggregate in families (114). Pure Lewy body pathology exists in only 20% to 30% of those who have symptoms of dementia with Lewy bodies, with most brains showing comorbid Alzheimer findings such as plaques and tangles (105; 63).
Frontotemporal dementia. This is a heterogeneous group of disorders that comprise about 10% to 20% of all dementias worldwide. Mutations in three of the tau genes (MAPT, GRN, and C9orf72) have been significantly associated with the frontotemporal dementias (40). Most cases begin between 55 and 65 years of age. The most common syndromes are the behavioral variant and the language variants (progressive nonfluent aphasia and semantic dementia). The GGGGCC repeat expansion in the C9orf72 gene is the most common cause of familial frontotemporal dementia (24). When the C9orf72 gene is associated with behavioral variant frontotemporal dementia, the disease can present with hallucinations and delusions. This gene is also associated with the parkinsonism/ALS phenotype of frontotemporal dementia.
Ophelia syndrome. This is an unusual neuropsychiatric disorder that is characterized by loss of memory, depression, hallucinations, and bizarre behavior, otherwise known as limbic encephalopathy (85). It is caused by circulating antibodies to neuronal surface antigens (mGluR5), and it is reversible in patients for whom the cause is Hodgkin lymphoma.
Chronic traumatic encephalopathy. Clinically, this condition is manifested by behavioral and personality changes, parkinsonism, and speech and gait disorder (153). Pathologically, it is characterized by diffuse atrophy of the cerebral cortices, the mammillary bodies, and a fenestrated cavum septum pellucidum. It is distinguished from other tauopathies in that there is a propensity for tau deposits in the depths of the sulci and in astrocytes, as well as neurons (103). Studies have shown that serum biomarkers of axonal injury (total tau) and astroglial injury (S-100 calcium binding protein B) were elevated in concussed professional hockey players compared to preseason values (147). There were no significant changes measured in neuron-specific enolase levels, arguing for a larger acute effect on axons and glia rather than neurons. Football players with and without concussion have been shown to have smaller hippocampal volumes, compared to age-matched controls (148). Those with concussion had smaller hippocampal volumes than those without concussion.
Mild cognitive impairment. It is estimated that five to 11.6 million Americans are affected by mild cognitive impairment, larger numbers than the four to five million who have Alzheimer disease (125). The Rush Alzheimer Center followed a large group of normal older persons and found an accelerated cognitive decline three to four years prior to the diagnosis of mild cognitive impairment (174). Cognitive decline accelerated again five to six years prior to the diagnosis of Alzheimer disease. The prevalence of mild cognitive impairment is age-dependent: 6.7% for ages 60 to 64 years, 10.1% for ages 70 to 74 years, and 25.2% for ages 80 to 84 years (125).
Dementia. In a large epidemiologic study of insured patients in northern California, dementia diagnoses were taken from inpatient and outpatient medical encounters from 2000 to 2013 (101). It showed that Asian Americans had a lower risk of dementia (15.2 out of 1000 person-years), compared to Latinos (19.6 out of 1000 person-years), whites (19.3 out of 1000 person-years), or African Americans (26.6 out of 1000 person-years). The cumulative risk for dementia at age 65 was 38% for African Americans, 32% for Latinos, 30% for whites, and 28% for Asian Americans. Although vascular disease was one possible explanation for the elevated dementia risk in African Americans, the racial/ethnic inequalities persisted after adjustment for vascular comorbidities. It is possible that differences in education could contribute to the different dementia risks among the various racial/ethnic groups (not measured in this study). In a large longitudinal Japanese study, the prevalence of Alzheimer disease and all-cause dementia increased from 1985 (6.8%) to 2012 (11.3%) due to increased incidence and survival (118).
Alzheimer disease. Alzheimer disease is the most common type of dementia (it is listed as the sixth leading cause of death in the United States). According to the 2015 statistics from the Alzheimer’s Association, one in nine Americans aged 65 and older has been diagnosed with Alzheimer disease or another dementing disorder (137). It is estimated that 14.7% of people older than 70 in the United States has dementia. Although the major risk factor for Alzheimer disease is age, there are other risks, such as the apolipoprotein-4 allele, lower level of education, smaller social networks, hippocampal atrophy, and abnormal amyloid PET (10; 66). Typical Alzheimer disease accounts for 55% of cases (more female), whereas early-onset (hippocampal-sparing Alzheimer disease) accounts for 17% (more male), and limbic predominant Alzheimer disease accounts for 21% (more female) (41). Mortality risks in Alzheimer patients are higher in males and those with lower MMSE, higher numbers of medications, and older age (46).
Vascular dementia. In a 20-year prospective population-based study, it was shown that a higher degree of atherosclerosis in midlife was associated in later years with an increased risk of vascular dementia (HR=1.32) and small vessel disease (HR=1.47), but not with Alzheimer disease (HR=0.95) (55).
Dementia with Lewy bodies. Mortality risk is higher in dementia with Lewy bodies than in Alzheimer disease (HR=1.64) (46).
Frontotemporal dementia. Mortality risk is higher in frontotemporal dementia than in Alzheimer disease (HR=1.91) (46). Survival in frontotemporal dementia patients depends on the clinical subtype. For example, the shortest survival (two to five years) is seen in those who have the motor neuron disease subtype (170). Those with the most common subtype (the behavioral variant) live longer (five to eight years), and the language subtypes (semantic dementia, primary progressive aphasia) live the longest (10 to 12 years). Although most types of frontotemporal dementia begin before the age of 65, there are still about 25% that begin in later years (146). In particular, the behavioral variant of frontotemporal dementia has a mean age of onset of 64, whereas the semantic variant begins at 67, and primary progressive aphasia begins around 73 (25).
Chronic traumatic encephalopathy. The longer an American football player works at the game, the greater the risk of their developing the pathology of chronic traumatic encephalopathy (odds ratio = 1.3 per year) (107). Those patients with the pathological diagnosis were 10 times as likely to have played more than 14.5 years, compared to participants in the study who did not show the pathology of chronic traumatic encephalopathy.
Transient memory loss. In metabolic and hypoxic encephalopathies (eg, acute confusional states, delirium), memory loss is a common complaint. Other deficits can be seen in patients with delirium, such as change in level of consciousness. Transient ischemic attacks involving the hippocampus (eg, transient global amnesia) can produce transient confusion and impaired recent memory (156). Those receiving electroconvulsive therapy may notice a brief period of memory loss, but they almost always recover (23). After closed-head injury, it is not uncommon for the patient to experience both retrograde and anterograde amnesia for at least one to two days (96).
Subjective cognitive decline. This syndrome is a condition in which older adults complain of memory decline, but memory deficits cannot be measured on cognitive testing. This is unlike the situation with mild cognitive impairment, in which memory loss is documented to be at least 1.5 SD below normal (142; 68).
Mild cognitive impairment. This clinical syndrome is a transitional state between normal aging and dementia (127; 124; 125) in which memory difficulties occur in the absence of change in functional abilities. Studies have emphasized the importance of adequately treating hypertension, diabetes, obesity, and hyperlipidemia in midlife as a way of preventing cognitive impairment in later years (Kivipelto et al 2005; Whitmer et al 2005; 62; 135; 56; 173; 121; 102). A study pointed out how important it is to take a careful medication history in patients with memory complaints because many elderly patients have been taking anticholinergic drugs such as tricyclic antidepressants, antihistamines, and bladder antimuscarinics (52; 125). These drugs are associated not only with memory complaints but also with dementia. Other factors that may contribute to mild cognitive impairment include hearing loss, vision loss, medical illnesses such as kidney failure, and sleep disorders such as obstructive sleep apnea (43).
Alzheimer disease. The four most common causes of persistent memory loss include mild cognitive impairment, Alzheimer disease, dementia with Lewy bodies, and vascular dementia (169). Although those with Alzheimer disease have severe recent memory problems, those with vascular dementia are more impaired on semantic (long-term) memory tasks and executive (frontal lobe) function (51). When Alzheimer and Lewy body dementia patients were compared with neuropsychology tests, Alzheimer patients had more problems with verbal memory, whereas Lewy body patients had more difficulty with visual memory (116). In a comparison of Alzheimer and Lewy body patients who had comparable amounts of basal forebrain atrophy on MRI, the Alzheimer patients had more severe global impairment as determined by MMSE scores, whereas Lewy body patients had more visuospatial and executive impairment on the trail making test (53). Early-onset Alzheimer patients are more likely to have a nonamnestic syndrome, whereas typical Alzheimer and limbic-predominant Alzheimer patients are both characterized by an amnestic syndrome (41).
Vascular dementia. Those with pure subcortical vascular dementia perform better on delayed recall tasks than those with presumed Alzheimer disease (91). This explains why many vascular dementia patients complain more about their gait apraxia than their memory loss. Low ejection fraction in those with heart failure correlates significantly with reduced verbal memory function (42). Those with greater white matter lesion load and larger ventricles on MRI showed slower processing speeds and poorer episodic memory (34). A study of free and cued recall demonstrated that vascular dementia patients had better cued recall, compared to Alzheimer patients, suggesting that their problem was one of memory retrieval and not one of encoding (20). Patients with dementia associated with transient ischemic attack or stroke have cognitive and functional impairment associated with small vessel disease and white matter changes in the frontal lobes (179).
Dementia with Lewy bodies. These patients have memory loss, parkinsonism, visual hallucinations, and fluctuations in their levels of alertness over the course of a day (104). Dementia with Lewy body patients performed worse than Parkinson and multiple system atrophy patients on tests of verbal and visual memory, as well as tests of executive function (75). About 50% of those who have dementia with Lewy bodies have REM sleep behavior disorder that often precedes the memory loss by years or even decades (22; 104). Cagnin and associates did a comparison of early dementia patients and showed that those with dementia with Lewy bodies were more likely to perform poorly on the intersecting pentagon test, compared to those with early Alzheimer disease (18). They also had more impaired executive functions. Those with Lewy body disease have greater medial temporal atrophy than control subjects, but less than those with Alzheimer disease (104).
Frontotemporal dementia. These patients present with either behavioral changes (behavioral variant), language changes (progressive nonfluent aphasia, semantic dementia), or behavioral changes in combination with motor neuron disease or parkinsonism (170). Memory loss may appear to be superficially similar to Alzheimer disease and vascular dementia, but when free and cued recall was tested with the Grober and Buschke test, frontotemporal patients had better cued recall than Alzheimer patients (20). This suggested that they had a memory retrieval problem, rather than a memory encoding problem. MRI can be used as an adjunct to the clinical examination in identifying the various subtypes of frontotemporal dementia (158).
Chronic traumatic encephalopathy. These patients usually have a triad of cognitive, behavioral, and mood impairments in addition to headaches and motor disturbances (153). Those who die at an older age (mean, 54.5 years) are more likely to suffer from dementia (54%) and have the APOE-e4 genotype (18%). Those who die at a younger age (mean, 34.5 years) are less likely to have dementia (18%) and rarely have the APOE-e4 genotype (4.5%).
Depression. Memory loss is a common complaint in those with depression. About 8% of elderly individuals in the community have depression, and even higher percentages are reported in those with Alzheimer disease, vascular dementia, and dementia with Lewy bodies. Symptoms of depression and dementia overlap considerably: irritability, nighttime behavior changes, anxiety, appetite changes, agitation, and apathy. Two longitudinal studies found that symptoms of depression were seen earlier in patients who developed signs of mild cognitive impairment or dementia than in those who remained in the control group, suggesting that depression accompanies early signs of cognitive impairment (Richard et al 2013; 99). One large study comparing amyloid-PET-positive (85%) and amyloid-negative (15%) Alzheimer patients showed that amyloid-negative patients were more likely to be taking medications for depression and to have higher depression scores (87). These amyloid-negative patients were older; their disease progressed more slowly, and they were more likely to be APOE-e4 negative.
Malingering. On rare occasions, memory loss may be due to malingering. The clinical history may help to suggest this possibility, but a neuropsychological assessment is usually needed to verify this diagnosis. Unfortunately, memory loss can be falsely portrayed in such a way that it is often difficult to detect (58; 140).
Age-related cognitive decline. For years, it was thought that age was one of the causes of declining memory in the elderly. However, work of the Rush Alzheimer Disease Center showed that “age-related cognitive decline” was really due to early stages of one of the three common dementing illnesses, either Alzheimer disease, vascular dementia, or dementia with Lewy bodies (177). Now, data from another large longitudinal study have demonstrated that memory function declines steadily in normal adults after the age of 30 and that hippocampal atrophy also progresses after that age (66). The authors attributed these midlife memory changes to age because the amyloid PET scans did not become positive until about the age of 70.
The “worried well.” Complaints of memory loss can be seen in cognitively intact middle-aged and elderly individuals. This is especially true in family members who are caring for those with dementia. On formal neuropsychological testing, cognitively intact individuals can be readily distinguished from those with amnesic disorders. In neuropsychological studies of normal elderly individuals, delayed recall performance is negligibly affected (as a proportion of material initially learned), but immediate recall is less efficient in older individuals compared to younger subjects (126).
Transient memory loss. Young people with new memory loss are likely to have had recent exposure to a drug or to head injury, so they need a toxicology screen and a head CT or MRI scan. If the acutely confused person has bitten his tongue, lost bladder control, or has unexplained bruises, then an EEG is needed to look for a seizure focus. Anyone with a history of stomach surgery should be suspected of having B12 or B1 deficiency (this is particularly true of those who have had gastric bypass surgery). Those who have had gastric bypass surgery could have Wernicke-Korsakoff syndrome if they have memory loss in addition to nystagmus and gait ataxia (145). An MRI is needed to document the T2 signal changes in the periaqueductal grey matter (154). Thyroid function tests and B12 levels are both needed in elderly subjects with new memory complaints (167). Prescription drugs must be suspected as the cause of transient memory loss in older patients, especially if the newest drug has anticholinergic properties (19; 52). Those young or middle-aged people who have symptoms of limbic encephalopathy need an MRI to document the T2 signal changes in the mesial temporal cortex (85). A cluster of 14 young patients with acute amnestic syndrome associated with substance abuse was reported in Massachusetts in 2012 to 2016 (07). As many as 62% were associated with opiate abuse. MRI scans in these cases showed complete ischemia of both hippocampi. This study would support the practice of obtaining both an MRI and a toxicology screen whenever a patient has an unexplained episode of transient memory loss.
Alzheimer disease. Every new patient with mild cognitive impairment or dementia needs a CT or MRI of the head because in 5% of the patients, subdurals, brain tumors, or silent infarcts may be the cause of memory complaints (08; 164). MRI changes in those with mild cognitive impairment can predict who will go on to develop Alzheimer disease (44). Those with early-onset Alzheimer disease are more likely to have parietal-dominant atrophy, and those with late-onset Alzheimer disease are more likely to have mesial temporal atrophy or diffuse atrophy (117; 41). MRI is also needed to determine which patients are more likely to develop vascular dementia (severe white matter changes and stroke), according to Verdelho and colleagues and others (163; 179). Some have argued that extensive subcortical white matter changes on MRI are a predictor for more rapid cognitive decline and slower processing speeds (162; 34). The sensitivity of hippocampal atrophy on MRI for predicting Alzheimer disease within five years in those with amnestic mild cognitive impairment is 63%, whereas the specificity is 72% (168). Amyloid PET can be used to distinguish those with Alzheimer disease from various non-Alzheimer conditions (66; 87). It is particularly important to use in studies of new drugs for Alzheimer disease (44; 77).
Dementia with Lewy bodies. In contrast with Alzheimer disease, there is relative sparing of medial temporal structures on CT and MRI in dementia with Lewy bodies (104). Reduced dopamine transporter uptake in the basal ganglia on SPECT or PET is another sign that can distinguish dementia with Lewy bodies from Alzheimer disease (104). Another test that supports the diagnosis is polysomnography, if it confirms the diagnosis of REM sleep behavior disorder. EEG can be supportive of the diagnosis of dementia with Lewy bodies when it shows prominent posterior slow-wave activity with periodic fluctuations (104). Amyloid PET scans have also been used to distinguish patients who have dementia with Lewy bodies from those who have Alzheimer disease or those with mixed pathology (dementia with Lewy bodies and Alzheimer disease) (73).
Depression. Depression is a common, treatable comorbidity in those with mild cognitive impairment and dementia (08; 95). Twelve different behavioral changes in patients with Alzheimer disease, vascular dementia, or dementia with Lewy bodies (depression, irritability, apathy, anxiety, agitation, hallucinations, etc.) can be described and quantified by using the Neuropsychiatric Inventory (28). The advantage of this scale is that it assesses not only the patient’s symptoms, but also grades the severity of symptoms.
Mild cognitive impairment: medications. Cholinesterase inhibitors do not delay the onset of Alzheimer disease overall in patients with mild cognitive impairment, but treatment with donepezil is indicated in those who are clinically depressed (95). Donepezil may help symptomatically delay conversion of those with the apolipoproteinE epsilon4 genotype (about 40% of patients); this was demonstrated in a subanalysis, not prospectively (54). Vitamin E did not reduce the risk of progression to Alzheimer disease at any time point in this study (128). In a group of 216 prodromal Alzheimer disease patients, donepezil (vs. placebo) appeared to slow the annual rate of hippocampal atrophy, even though there were no neuropsychological differences between the two treatment groups (36). Control of diabetes is critical, because faster decline in cognitive function was present among African Americans and European Americans following the diagnosis of diabetes in old age (134). Treating hypertension in midlife and later years is also helpful in preventing dementia in later years (102; 172; 152).
Mild cognitive impairment: nonpharmacologic interventions. Several studies have emphasized the importance of treating blood pressure, diabetes, obesity and hyperlipidemia in midlife to prevent cognitive impairment or dementia in later life (173; 56). Active participation in cognitive tasks and physical activities are both effective in reducing the risk of developing dementia in those who have mild cognitive impairment (90). A Mediterranean diet has been shown to prevent both mild cognitive impairment and Alzheimer disease in a multiethnic community study (139) and in a large clinical trial of patients at risk for cognitive decline because of cardiovascular disease (150). The MIND diet (a hybrid of the Mediterranean diet and the DASH diet) emphasizes plant-based foods instead of animal products and is associated with a reduced incidence of cognitive decline (109). In a study of adults with cognitive impairment but no dementia, the largest improvements in executive function were seen in those randomized to both aerobic exercise and the DASH diet (13). There were no significant changes in memory or language function. Dietary omega-3 fatty acids from marine sources have been associated with a reduced risk of progression to dementia in community-dwelling elders (94). More frequent cognitive activity across the lifespan has been associated with a slower late-life cognitive decline that is independent of several common neuropathological conditions, which is consistent with the cognitive reserve hypothesis (176). A large randomized, controlled clinical trial showed that a multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring was effective at improving or maintaining cognitive function in a group of at-risk elderly individuals (115). They were assessed over a 2-year period with a comprehensive neuropsychological test battery. Weight loss in obese/overweight individuals (resulting in an average BMI decrease of 7 kg/m2) has been shown in a meta-analysis of 13 longitudinal studies and seven randomized controlled trials (n=551 participants) to be associated with a significant improvement in attention and memory (166). Future randomized trials need to examine whether this effect is explained by improvement in sleep patterns.
Alzheimer disease: medications. Several cholinesterase inhibitors (donepezil, rivastigmine, and galantamine) have been shown to improve cognition and behavior at all stages of Alzheimer disease (133; 144). In a prospective cohort study of Alzheimer disease patients who were imaged twice in one year with MRI, the annual rate of hippocampal atrophy in those on donepezil was less than that seen in controls, suggesting a neuroprotective effect of the drug (59). The two groups were comparable with respect to age, sex, disease duration, education, MRI interval, APOE genotype, and baseline cognitive test scores. Memantine improves cognitive functions in patients with moderate to severe stages of the illness (144). A study demonstrated that continued treatment with donepezil in patients with moderate to severe Alzheimer disease was associated with both cognitive and functional benefits over a 12-month period (64). Observational studies and clinical trials have shown that better control of systolic blood pressure reduces the incidence of Alzheimer disease and other dementias, especially when blood pressure lowering is started in middle age (172). In a nationwide case-control study in Finland, use of hormone replacement therapy in postmenopausal women was associated with a 9% to 17% increased risk of Alzheimer disease (9% with estradiol only; 17% with estradiol-progesterone) (138). Vaginal estradiol preparations were not associated with an increased risk of Alzheimer disease. There are currently 132 agents in clinical trials for the treatment of Alzheimer disease (27). These include agents to mitigate the damaging effects of beta amyloid, in addition to drugs aimed at treating neuropsychiatric symptoms of the disease.
Alzheimer disease: nonpharmacologic interventions. Caregiver support group meetings are particularly helpful in providing education to caregivers about the diseases that cause dementia and in addressing ways to manage behavioral changes (21; 144). Physical activity (especially aerobic exercise) attenuates the neuropathological changes in Alzheimer disease, and it positivity affects cognitive function and sleep, especially when it is started in the early stages of the disease (17; 130; 122; 112). In animal models of Alzheimer disease, physical activity improves spatial learning, reduces markers of oxidative stress, increases levels of BDNF protein, promotes the glymphatic clearance of beta amyloid, and reduces activation of astrocytes and microglia (60; 80). When Alzheimer patients were assigned to home-based exercise twice weekly (vs. usual care) for a year, the exercise group showed improvement in executive function, but verbal fluency and global function did not improve (119). Lifetime cognitive engagement has been associated with lower deposition of beta-amyloid in the brain, according to results of amyloid PET images (88). This suggests that cognitive engagement might influence the onset and progression of Alzheimer disease. One study has shown that lifetime intellectual enrichment (high education, high midlife cognitive activity) is associated with lower amyloid accumulation in the brains of Alzheimer disease patients who are APOE-e4 carriers (165). In the Rush Memory and Aging Project, early-life and middle-age cognitive activity influenced late-life cognitive decline, regardless of neuropathologic diagnosis, which was consistent with the cognitive reserve hypothesis (176). A 44-year longitudinal population study in women found that cognitive activity in midlife was associated with reduced risk of total dementia (HR 0.68; 95% CI 0.49-0.89) and Alzheimer disease (HR 0.54; 95% CI 0.36-0.82) (112).
Vascular dementia. Patients who have mild to moderate vascular dementia seem to benefit from cholinesterase inhibitors to a similar extent as those with Alzheimer disease (79). This is likely to be due to the fact that the brains of most vascular dementia patients show mixtures of both vascular pathology and Alzheimer changes (14). In a 6-month randomized controlled trial, aerobic exercise for 3 days per week (versus usual care and education) provided improvement on the ADAS-cog for 70 adults with vascular cognitive impairment (93). Aerobic and resistance exercise has been shown in longitudinal studies to reduce arterial stiffness and to improve endothelial function over time (80). Physical activity in midlife in women is associated with reduced risk of mixed dementia (HR 0.43; 95% CI 0.22-0.86) and vascular dementia (HR 0.47; 95% CI 0.28-0.78) (112; 144).
Dementia with Lewy bodies. Treatment with rivastigmine, galantamine, and donepezil have been demonstrated to improve cognition and behavioral symptoms (particularly visual hallucinations) in both dementia with Lewy bodies and Parkinson dementia (104; Hershey & Coleman-Jackson 2019; 144). Treatment with galantamine is not only effective at improving global function, but it has also been shown to reduce visual hallucinations and to prevent nighttime problems in patients with dementia with Lewy bodies (39). Cholinesterase inhibitors do not cause worsening of the parkinsonism symptoms of these patients. These drugs can be effective at reducing the syncopal episodes and falls that are sometimes seen in this disease. Memantine also improves global function in Lewy body patients (01; 104).
Frontotemporal dementia. In contrast to its beneficial effects in Alzheimer disease and dementia with Lewy bodies, memantine has not been shown to help patients who have the behavioral or semantic variants of frontotemporal dementia (15). In fact, more patients in the memantine group in this clinical trial developed cognitive adverse events, compared to those assigned to the placebo group. This effect of behavioral worsening with cognitive therapy had been reported earlier when donepezil was used in frontotemporal dementia patients (106). Several nonpharmacological methods have been shown to be helpful for managing behavioral symptoms in patients with frontotemporal dementia, including reducing the noise level, lessening clutter, and reducing the number of people involved in public outings (09). Walking the patient on a regular schedule seems to help improve sleep quality, but the benefit of exercise in general has not been uniformly demonstrated in all the clinical trials.
Multiple sclerosis. Randomized trials do not support the use of donepezil in treating memory loss in patients with multiple sclerosis (84).
Alzheimer disease. When Alzheimer patients from three large clinical trials were compared, use of donepezil at five mg/day or more was associated with a significant delay in nursing home placement by at least 21 months (47). The models used in this study were adjusted for age, sex, baseline Mini-Mental State Examination score, and whether the caregiver was a spouse or not. When 716 older adults without dementia were monitored with actigraphy in the Rush Memory and Aging Project and followed for about four years, a higher level of physical activity was associated with a significantly reduced risk of Alzheimer disease (hazard ratio = 0.477) (17).
Dementia. Using the Swedish Death Registry (2007-2015), survival prediction tables were developed for those with newly diagnosed dementia. By 2016, 41.6% of the dementia cohort had died, and the most potent predictors of mortality included older age, male sex, greater comorbidity, lower baseline cognitive function, having a diagnosis of non-Alzheimer dementia, living alone, and using more medications (57).
Linda A Hershey MD PhD
Dr. Hershey of the University of Oklahoma Health Sciences Center has no relevant financial relationships to disclose.See Profile
Sergio Ramirez-Salazar MD
Dr. Ramirez Salazar of the University of Oklahoma Health Sciences Center has no relevant financial relationships to disclose.See Profile
Martin R Farlow MD
Dr. Farlow of Indiana University received research grant support from AbbVie, Biogen, Boehringer Ingelheim, Eisai, Eli Lilly, Genentech, Roche, Novartis, Suven Life Sciences Ltd, and vTv Therapeutics; fees from Cerecin/Accera, Allergan, Avanir, AZ Therapies, Eli Lilly, Kyowa Kirin Pharma, Longeveron, Medavante, Merck, Neurotrope Biosciences, Proclara, Takeda, and vTv Therapeutics for consultancy, or advisory board/DSMB membership; patent licensing fees from Elan; and consulting fees from Cortexyme, Green Valley, Regenera, Samumed, Zhejiang Hisun Pharmaceuticals, Cognition Therapeutics, Danone, Eisai, and Otsuka.See Profile
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Jan. 18, 2022
After carpal tunnel syndrome, the most common median nerve entrapment is the pronator teres syndrome. The most common features of the pronator teres syndrome are insidious proximal forearm fatigability, pain, and tenderness amplified by exercise and, at times, radiating to the shoulder. Other less common entrapment sites include the ligament of Struthers, lacertus fibrosus, and the tendinous origin of the flexor digitorum superficialis.
Jan. 02, 2022
Huntington disease (HD) is a neurodegenerative disorder characterized by a combination of progressive motor, cognitive, and psychiatric symptoms. Chorea is the most common movement disorder in HD, and it tends to slow and may be replaced by dystonia-rigidity in the end stages. Cognitive and behavioral changes may occur years prior to the onset of definitive motor signs, simultaneously with or after motor manifestation of the disease.
Dec. 30, 2021
Neurovascular injury is a broad topic that includes injury to different neuroanatomical sites. They can occur either extracranially or intracranially and can manifest as an arterial dissection, pseudoaneurysm, fistula formation, and thrombosis or occlusion of the involved vessel. A high index of suspicion is needed to diagnose vascular injuries in an accurate and timely manner because most patients have no focal neurologic deficit on presentation.
Dec. 08, 2021
Sleep disturbances are common after traumatic brain injury, affecting 30% to 84% of individuals, with varying degree of head injury. Not only can they
Dec. 04, 2021
Neuro-Ophthalmology & Neuro-Otology
Toxic or nutritional optic neuropathy is classically characterized by gradual painless progressive vision loss, bilateral central or cecocentral scotomas, marked dyschromatopsia, loss of high spatial frequency contrast sensitivity, temporal pallor, and loss of papillomacular bundle. A thorough history of medication use, toxic exposure, substance abuse, dietary deficiency, past surgeries, family history, and peripheral neurologic symptoms should be documented. Early recognition, removal of toxic agents, and supplementation of nutritional deficiencies may lead to protracted visual recovery.
Dec. 02, 2021
Most traumatic spinal cord injuries occur in association with impact to the vertebral column, resulting in direct compression or disruption of the spinal cord. Secondary injuries may ensue, resulting from ischemic and inflammatory processes, disrupted homeostasis, and apoptosis. The American Spinal Injury Association (ASIA) Impairment Scale is an international classification of spinal cord injury based on neurologic deficits, including motor function and sensation, as well as bowel and bladder control from the S4 and S5 segments.
Dec. 01, 2021
Behavioral & Cognitive Disorders
Normal pressure hydrocephalus (NPH) is characterized by gait disorder, cognitive decline, and urinary incontinence. Hydrocephalus in NPH is a consequence of the disequilibrium between production and absorption of CSF. In the majority of cases, ventricular enlargement results from an obstruction of the CSF flow around the brain convexities and insufficient absorption through the arachnoid granulations and arachnoid villi of the superior sagittal sinus.
Dec. 01, 2021