Abnormal Sleep May Foreshadow Alzheimer’s

Abnormal Sleep May Foreshadow Alzheimer’s
A brief sleep questionnaire could catch disease onset earlier.

A study published in Clinical Interventions in Aging reports that a brief sleep questionnaire could detect abnormal sleeping behaviors associated with the development of Alzheimer’s disease. Abnormal sleep behavior is common in people with Alzheimer’s disease and may appear before the onset of any clinical symptoms.

“These questionnaires can be administered and interpreted by family members at home and may help determine when to seek additional cognitive or neurobehavioral assessments,” said Sepideh Shokouhi, Ph.D., lead investigator on the study and research assistant professor of psychiatry and behavioral sciences at Vanderbilt University Medical Center.

Sleep and Alzheimer’s Disease

 Alzheimer’s disease is characterized by abnormal accumulations of beta amyloid and tau proteins in the brain. Recent studies have found associations between abnormal sleep-wake patterns and beta amyloid. Less is known about the relationship between sleep and tau.

“A lot of these studies have involved the recording and monitoring of extensive sleep data by clinicians,” Shokouhi said. “We wanted to see whether simple sleep questionnaires could also be used to link abnormal sleep behavior with early Alzheimer’s disease pathologies.”

A Simple and Informative Questionnaire

Shokouhi’s team found that abnormal nighttime behaviors, like restlessness, wandering and pacing, detected using caregiver questionnaires were not only significantly associated with beta amyloid accumulation in the brain, but also increased tau levels.

The study included 35 cognitively unimpaired people enrolled in the Alzheimer’s Disease Neuroimaging Initiative, a longitudinal multicenter study focused on early detection and tracking of Alzheimer’s disease. The researchers analyzed imaging and behavioral data from study participants who underwent both beta amyloid and tau brain scans at time points close to their sleep assessment.

Positron emission tomography (PET) was used to calculate beta amyloid and tau accumulation. Sleep and nighttime behavior changes were assessed using the Neuropsychiatric Inventory Sleep Questionnaire, which poses a simple set of questions to an informed caregiver.

“The questionnaire uses eight questions to understand the specific nature of the sleep problems,” Shokouhi explained. “Does the individual have difficulty falling asleep? Do they sleep excessively during the day? Do they wake up too early in the morning and think it’s time to start the day?”

Sleep deficiency without nighttime behavioral symptoms, like difficulties falling asleep, fragmented sleep, or awakening too early, were associated with lower levels of tau and showed no association with beta amyloid levels in the brain. Shokouhi says more research is needed to clarify sleep and tau relationships. However, she suspects that self-reports, rather than the current caregiver questionnaire, may be better at detecting these sleep deficiencies.

A Valuable Screening Tool

While more research is needed, Shokouhi believes sleep reports provided by caregivers could be a valuable screening tool for early stages of Alzheimer’s disease.

“Detailed characterization of sleep-wake patterns can serve as an early and non-invasive way to assess a patient’s pathological profile,” Shokouhi said. “If this screening measure can be done in such a simple way – at home, by family members, using a questionnaire – maybe it will help catch cases of Alzheimer’s earlier.”