Sleep Well and Recall in the Morning

Memory improves with nighttime sleep in Parkinsons disease

(RxWiki News) A good sleep can feel like a huge boost for your memory and thinking. This is because sleep actually does boost mental functioning! For those already living with cognitive impairment or memory issues, a good night’s sleep can make a huge difference.

A recent small study examined the importance of night time sleep on working memory in patients with the neurodegenerative disorders, PD and dementia with Lewy bodies (DLB).

The study found that working memory improved after a good nights’ sleep in patients with PD who took dopamine related medication.

Those with PD who did not take dopamine related medication and those with DLB did not improve their working memory after nocturnal sleep.

"Get a full night’s sleep."

The most common symptoms associated with PD are tremors and movement difficulties but PD can also cause difficulty with memory and thinking processes.

DLB is a condition that is similar to both Alzheimer’s disease and PD. DLB patients experience cognitive decline similar to that seen in Alzheimer’s and loss of motor control similar to PD symptoms.

Senior author Donald Bliwise, professor of neurology at Emory University School of Medicine and team examined data from 53 PD and 10 DLB patients.

Participants were given the Mini-Mental State Examination to determine whether they had dementia.

PD patients were evaluated with the Hoehn and Yahr staging scale and the motor component of the Unified Parkinson’s Disease Rating Scale (UPDRS) to determine the progression of their condition.

Study participants were also evaluated for restless legs syndrome and current medication use.

Participants in the study stayed in an inpatient sleep laboratory for 48 hours. They underwent tests that included two nights of sleep testing and eight verbal number memory tests forward and backward tests.

In the number memory tests, the study participant was read a string of digits which they immediately repeated forward and backward. The number of digits they were required to remember grew incrementally until a mistake was made.

The ability to recite the digits forward reflects short-term memory and attention while the ability to repeat the digits backwards is associated with working memory.

The digit testing occurred about two hours after waking up in the morning and was repeated every two to three hours until four tests were taken that day.

Maintenance of Wakefulness testing was conducted while patients were at the sleep laboratory to determine daytime alertness.

The sleep testing monitored sleep quality, sleep disruption, oxygen levels, breathing events, leg movements, dream enactment and REM.

The patients with PD who were on medication improved their performance after nocturnal sleep on the backward digit test but not on the forward test. Improvement was not seen during the course of the day.

Backward and forward digit test results did not improve in those with PD not taking dopamine related medication despite having a shorter period of disease diagnosis than those on medication.

The patients with DLB did not improve on the backward digit span test and declined in performance on the forward digit span test.

Those with sleep apnea severe enough to lower blood oxygen levels for longer than five minutes did not improve their working memory overnight.

Although oxygen levels and medication affected working memory performance, slow-wave sleep, the deepest level of sleep, remained the most important factor of working memory performance.

This result confirms recent research that says slow-wave sleep promotes brain plasticity and memory. It also emphasizes the importance of addressing any sleep disorders in patients with PD.

“This is important research showing the correlation between sleep and memory and the possibility of being able to modify memory in some patient's with Parkinson's disease.” Says William Kohler, MD, the director of the Florida Sleep Institute in Spring Hill, Florida. “Data continues to accumulate on the importance of sleep.”

The study was published in the August issue of Brain.

The study was funded by the National Institutes on Health. One author was partially supported by a Cottrell Fellowship from Emory University School of Medicine.

No conflicts of interest were reported.

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Review Date: 
August 27, 2012