Caffeine supplements given to Parkinson's patients didn't help them stay awake, but they did improve some of their symptoms, according to a new study appearing in the journal Neurology.

Parkinson's disease is a neurodegenerative aliment that is estimated to affect around 500,000 people in the U.S. alone.

In a small trial, 61 Parkinson's patients who complained of daytime sleepiness and motor symptoms were either given a placebo or a 100-mg caffeine pill twice a day for three weeks. Then their dosage was bumped up to 200-mg (the equivalent of somewhere between two and four cups of coffee) twice a day for another two weeks.

At the end of the six-week period, patients who took the caffeine supplements had slight improvements with some of their symptoms compared to patients who took placebo pills. These improvements included lessened severity of motor symptoms, greater speed of movement and less stiffness. The researchers didn't observe any improvement in sleepiness among the caffeine-taking patients, however.

"Studies have shown that people who use caffeine are less likely to develop Parkinson's disease, but this is one of the first studies in humans to show that caffeine can help with movement symptoms for people who already have the disease," author Ronald Postuma of McGill University said in a statement Wednesday.

Postuma noted that while the improvement the researchers saw provided a modest benefit to Parkinson's sufferers, it was probably not enough to explain caffeine's allegedly preventive effects on the degenerative disorder, which are still being studied.

In a paper published this past April in the American Journal of Epidemiology, a team of scientists from the National Institutes of Health analyzed nearly 305,000 participants in an NIH survey and found that caffeine intake meant lower risk for developing Parkinson's disease in both men and women.

Postuma and his colleagues also noted that their study took place over a relatively short time period, and that the benefits of caffeine could lessen over time.

Nevertheless, "the study is especially interesting since caffeine seems to block a malfunctioning brain signal in Parkinson's disease and is so safe and inexpensive," Massachusetts General Hospital's Michael Schwarzschild, who wrote an editorial accompanying the paper, said in a statement.

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