Parkinson’s patients who have had the disease for a long time, who do not sleep very efficiently, and have higher motor impairment are more likely to experience sleep benefit — the phenomenon in which Parkinson’s patients wake up feeling better before taking medication.
The study with that finding, “The related factors of sleep benefit in Parkinson’s disease: A systematic review and meta-analysis,” was published recently in PLOS One.
Sleep benefit is, as the investigators wrote, “a fascinating, but mysterious phenomenon.” It is reported to happen in between a third and half of Parkinson’s patients.
The phenomenon is essentially when a person wakes up from sleep and feels better, with fewer disease symptoms. This is particularly puzzling for clinicians because, at least in theory, just waking up is often when a person has no medications helping them along. So, what could cause sleep benefit?
Researchers still are not sure. Some reports suggest that, although patients may report feeling better, they do not actually perform better on objective motor control tests. aAs such, it might all be psychological.
Still, the team wondered whether patient characteristics — from age and sex to sleep patterns and disease score — might predict which patients would experience sleep benefit.
After a search of the existing scientific literature, the investigators identified seven studies reporting on sleep benefit that included more than 1,300 Parkinson’s disease patients. Using the data from these studies, the authors looked for statistical trends to see which patient traits might be associated with experiencing sleep benefit.
Most of the factors they looked at, including sex, age at diagnosis, and sleep length, did not have a significant association with sleep benefit. However, the investigators did identify three factors that were predictive of experiencing sleep benefit: having had Parkinson’s for a long time; having a low sleep efficiency; and having a high score on the MDS-UPDRS-Ⅲ, a scale used to assess the severity of Parkinson’s motor symptoms, while on medication.
These results might let researchers determine which patients are most likely to experience sleep benefit, though what causes this phenomenon is still pretty much unknown.