Nancy Foldvary-Schaefer, DO, MS is Director of the Sleep Disorders Center and Staff in the Epilepsy Center. She is Professor of Medicine at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University with a Joint Appointment in the Women’s Health Center at Cleveland Clinic.

Certified by the American Board of Neurology and Psychiatry in Neurology, Clinical Neurophysiology and Sleep Medicine and the American Board of Clinical Neurophysiology, she has treated patients with sleep disorders and epilepsy at Cleveland Clinic since 1995. She has served as a lead investigator on numerous clinical trials and has published on sleep and epilepsy, epilepsy surgery, EEG, women’s issues in epilepsy and sleep disorders. She joined us to discuss the link between disruptive sleep and cognitive decline.

Read the Q&A with Dr. Foldvary below.

WAM: What is going on in the brain during sleep that makes it such an integral part of brain health?
Dr. Foldvary: Sleep is a function of the brain that restores every cell of every organ in our bodies (including the brain itself), clearing toxins and debris that accumulate during wakefulness. We cycle through REM and non REM sleep. Deep NREM sleep and REM sleep function to promote learning, memory and mood. Recent studies show how deeply NREM sleep clears toxins in the brain that promote Alzheimer’s. 

WAM: How does disrupted sleep affect the onset and progression of Alzheimer’s disease and other dementias? Does poor sleep directly contribute to cognitive decline?
Dr. Foldvary: We are learning that poor sleep and short sleep (quality and quantity) lead to cognitive impairments with age and dementia in some, similar to the well-known associations between short sleep and obstructive sleep apnea (OSA) on cardiovascular and metabolic health. Disorders such as sleep apnea interrupt sleep, especially deep stages that can affect brain health. OSA also creates repetitive arousals and oxygen desaturation that lead to a pro-inflammatory state that can cause cerebrovascular (and cardiovascular) events. Another aspect of this story is the parasomnia REM Behavior Disorder (RBD) that is caused by a lesion in the brainstem that leads to the loss of muscle paralysis in REM sleep. RBD can be confirmed by careful interpretation of the EMG signals on an overnight sleep study (our lab scores this routinely now). Over 90% of people with RBD develop an alpha synnucleopathy (Parkinson’s disease, multiple system atrophy or Lewy body dementia in 10-12 years). So RBD is a biomarker of some forms of neurodegeneration.

WAM: What about the opposite–can dementia and neurodegeneration also negatively impact sleep quality? Should I get screened for Alzheimer’s and other dementias if I’m having trouble sleeping?
Dr. Foldvary: Yes. Patients with neurodegenerative disorders are known to have chronic insomnia, leading to a vicious chicken-and-egg cycle. We are publishing a study on OSA and insomnia risk in various neuro populations and found high prevalences of both disorders in patients seen in Movement Disorders AND that sleep scores correlated with PD severity instrument scores. Large scale studies of outcomes with treatment of sleep disorders are lacking but needed.

WAM: What sleep habits do you recommend people prioritize if they want to maintain cognitive health as they age? When should they seek treatment?
Dr. Foldvary: Adults require 7-9 hours of sleep per night. Symptoms of chronic insomnia and sleep apnea should be evaluated and treated given we know that treatments improve many medical and psychiatric outcomes. Consider sleep foundational to health and wellness, similar to diet and exercise. In the US, we invest millions of dollars annually on diets and exercise, but ignore sleep. The triad goes together. You cannot optimize health without good sleep.