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Sleep disorders prevalent in elderly with neurodegenerative disorders

Sleep disorders are highly prevalent and negatively impact quality of life in older adults with neurodegenerative disorders; however, they are also often underdiagnosed, data published in Psychiatric Annals showed.

“Aging is associated with a reduced ability to initiate and maintain sleep,” Muna Irfan, MBBS, assistant professor, department of neurology, University of Minnesota, and director, sleep medicine fellowship, Minnesota Regional Sleep Disorders Center, and colleagues wrote. “Due to the overlap between psychiatric problems and neurodegenerative symptoms, psychiatrists are uniquely positioned to encounter aging patients with neurodegeneration and concurrent sleep disturbances.”

There are two major categories of neurocognitive disorders: tauopathies, which include Alzheimer’s disease, and synucleinopathies, which include dementia with Lewy bodies and Parkinson’s disease.

Synucleinopathies

Sleep disturbances in synuclein neurogenerative disorders include REM sleep behavior disorder, insomnia and obstructive sleep apnea. REM sleep behavior disorder can begin as early as decades before the clinical manifestation of Parkinson’s disease and dementia with Lewy bodies, according to the authors. Irfan and colleagues wrote that treatment with clonazepam and melatonin may be beneficial for controlling nocturnal behaviors, and they recommend regular surveillance of patients with REM sleep behavior disorder for the early detection of Parkinson’s and dementia.

Managing insomnia, the most prevalent sleep disturbance, needs an individualized approach and clinicians should be cautious of using pharmacological options because of the risks for falling and confusion among older adults, the researchers advise. The prevalence of excessive daytime sleepiness also rises with Parkinson’s disease progression. Before treatment, careful assessment of all the factors involved, such as lowering of medication doses, is warranted.

Insomnia, circadian rhythm disorder with early morning awakenings, REM sleep behavior disorder, visual hallucination, and nocturnal confusional wandering are common in patients with dementia with Lewy bodies, the authors wrote. Video polysomnography recording should be used to help distinguish between confusional arousals arising out of non-REM sleep and REM sleep behavior disorder.

Tauopathies

Sleep-wake disturbances can occur in up to 25% to 40% of patients with Alzheimer’s disease, according to Irfan and colleagues.

Prior research has shown that short sleep duration, poor sleep quality and longer sleep latency are associated with accumulation of beta amyloid protein in the brain, and that beta amyloid level concentrations in the brain increase during wakefulness and decrease during sleep, which indicates that sleep facilitates beta amyloid clearance. One study examining cognitively normal elderly patients with the APOE4 gene found that sleep consolidation significantly cut the incidence of Alzheimer’s disease. These findings together suggest that changes in sleep or activity parameters could be an early biomarker of later Alzheimer’s disease.

People with Alzheimer’s disease also often experience circadian sleep rhythm disturbances, which directly relate to the severity of the disease, Irfan and colleagues wrote.

“It is assumed that dysfunction of the suprachiasmatic nucleus resulting in alterations in melatonin secretion rhythm is the primary cause of circadian dysfunction in [Alzheimer’s disease]; however, melatonin supplementation has failed to show improvement in the sleep-wake cycle, raising concerns for melatonin receptor degeneration as well,” the authors explained.

Previous study data suggest patients with Alzheimer’s disease are five times more likely to present with obstructive sleep apnea compared with those without cognitive deficits. Treatment with continuous positive airway pressure may improve cognitive functioning and delay dementia progression in patients in early stages of Alzheimer’s disease with obstructive sleep apnea, prior research has shown.

“Awareness of sleep disturbances by psychiatrists is essential, as these patients have a high psychiatric burden and are frequently underdiagnosed,” Irfan and colleagues concluded. “Thus, increased understanding of sleep disturbances can pave the way for a holistic and multidisciplinary management plan.” – by Savannah Demko

Disclosure: The authors report no relevant financial disclosures.