Sleep and dementia

Linda A Hershey MD PhD (Dr. Hershey of the University of Oklahoma Health Sciences Center has no relevant financial relationships to disclose.)
Kristen Veal BA (Ms. Veal of the University of Oklahoma Health Sciences Center has no relevant financial relationships to disclose.)
Ahmed Koriesh MD (Dr. Koriesh of the University of Oklahoma Health Sciences Center has no relevant financial relationships to disclose.)
Antonio Culebras MD, editor. (

Dr. Culebras of SUNY Upstate Medical University at Syracuse received an honorarium from Jazz Pharmaceuticals for a speaking engagement.

)
Originally released September 9, 1993; last updated December 12, 2017; expires December 12, 2020

Overview

Disordered sleep and dementia are 2 neurologic issues that are found in many of the same patients and may indeed interact. The sundown syndrome is common in Alzheimer disease and other dementing illnesses. REM sleep behavior disorder can herald a synucleinopathy, such as dementia with Lewy bodies or Parkinson disease. The treatment of excessive daytime sleepiness and insomnia in dementia patients is not well described because many medications have risks that outweigh their benefits. Nevertheless, REM sleep behavior disorder has been shown in clinical trials to respond to both clonazepam and melatonin. Continuous positive airway pressure therapy can improve cognition in some cases of obstructive sleep apnea.

Key points

 

• Various sleep problems such as insomnia, hypersomnia, circadian rhythm disorders, sleep-disordered breathing, and REM sleep behavior disorder are more prevalent in patients with dementia than in age-matched controls.

 

• In the preclinical stages of Alzheimer disease, poor sleep efficiency appears to be associated with greater cerebral beta-amyloid burden, whether it is measured by amyloid PET imaging or by CSF A-beta levels.

 

• Polysomnography is valuable as a diagnostic tool, as relatively common sleep disorders such as obstructive sleep apnea and REM sleep behavior disorder are diagnosed based on the sleep study results.

 

• Bright light has been used effectively to manage the sundown syndrome, which is relatively common in patients with Alzheimer disease and other dementing illnesses.

 

• REM sleep behavior disorder is more common in patients with synucleinopathies.

 

• Melatonin and clonazepam are both effective in reducing symptoms of REM sleep behavior disorder, which is common in dementia with Lewy bodies and Parkinson disease.

Historical note and terminology

Sundown syndrome. “Sundowning,” or the nocturnal exacerbation of delirium, agitation, and aggressiveness has been recognized since the time of Hippocrates. Cameron first explored sundowning experimentally and reported that demented patients brought into a dark room during the daytime soon became agitated and confused (Cameron 1941). The sundown syndrome is now broadly used to describe a set of neuropsychiatric symptoms that begin in the afternoon or early evening, including confusion, anxiety, pacing, wandering, and resistance to redirection (McCann et al 2004; Khachiyants et al 2011; Canevelli et al 2016).

Insomnia. Chronic insomnia is the most prevalent sleep disorder in the general population (Schutte-Rodin et al 2008). It is manifested by difficulty in getting to sleep, staying asleep, and in reduced quality of sleep with daytime consequences.

REM sleep behavior disorder. This condition was initially described in humans in 1985 (Schenck et al 1985). It is manifested by violent behaviors, dream re-enactment, vocalizations, or involuntary leg movements during rapid eye movement (REM) or dreaming sleep, and it has been strongly linked to a set of neurodegenerative disorders known as the synucleinopathies, which include Parkinson disease, dementia with Lewy bodies, and multiple system atrophy (American Academy of Sleep Medicine 2005; Ferman et al 2011).

Sleep-disordered breathing. Symptoms of obstructive sleep-disordered breathing can vary from significant snoring with frequent arousals to complete airway obstruction with apneas. There has been mixed evidence in the past concerning the association of sleep-disordered breathing with dementia because it is hard to know about the directionality of the association (Plassman et al 2007; Ancoli-Israel et al 2008; Dyken et al 2009; Dyken and Im 2009). The difficulty with the older studies was their cross-sectional in design. Prospective studies have documented a cause and effect relationship between sleep-disordered breathing, intermittent hypoxemia, and the risk of mild cognitive impairment and dementia (Yaffe et al 2011; Osorio et al 2015).

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