Parkinson's disease (PD) is a neurological disorder that is characterized by tremors, difficulty in co-ordination and slow movement. Another significant feature is the destruction of the dopamine- producing neurons in the brain of PD patients and the low levels of dopamine in the brain cells. The condition usually affects people over the age of 50 years.

A group of scientists who carried out a study on PD patients have revealed that many of them reported better motor skills when they wake up in the morning, after a good night's sleep or after their afternoon nap. This phenomenon is known as the 'sleep benefit', defined as "a clear decrease in PD symptoms after a period of sleep."

Research was carried out on 243 people who answered a comprehensive screening questionnaire covering a range of motor and non-motor PD symptoms. The study found that regular daytime naps were taken by 98 patients, of whom 46% had no sleep benefit, 20.4% reported sleep benefit after both night sleep and afternoon naps, 20.4% reported benefit only after night sleep, and 13.3% of patients reported benefit only after a daytime nap.

"It is tempting to speculate whether daytime naps might constitute a possible therapeutic application," says lead researcher Dr. Sebastiaan Overeem, M.D., Ph.D. "If the subjective experience of sleep benefit is proven to be related to an objective improvement in motor function, this could have considerable clinical benefits,"he adds.

There was no difference in age at onset, disease duration, or type of treatment (clinical variables) or depression, memory, quality of life scores, fatigue, or apathy(demographic variables) experienced by those who benefitted from sleep and those who didn't.

"Sleep benefit remains an intriguing but elusive phenomenon, which deserves renewed attention and further research," remarked the researchers whose study was published in the Journal of Parkinson's disease.

Although they could not come up with a single reason as to why the patients benefitted from sleep, they believed that some possible reasons could include improved functioning of dopamine after sleep or the effect that sleep has on the circadian rhythm of the PD affected individual.

Sebastiaan Overeem remarks that the results are based on the patient's subjective judgment and recommends objective quantifications for motor performance and longitudinal assessment of Parkinson's disease symptoms during future studies. He works at the Department of Neurology, Donders Institute for Brain, Cognition, and Behavior, Radboud University Nijmegen Medical Centre, The Netherlands.

"Further study is important to identify possible determinants and the underlying mechanisms of sleep benefit, in order to identify those patients most likely to benefit from sleep. Both our research and previous studies show it's important to renew research on this intriguing subject, " he concludes.

Reference:
Overeem.S et al.,Journal of Parkinson's Disease (June issue) 2012

Source-Medindia