Playing virtual sports on the Nintendo Wii, an interactive video game console that makes players feel like they're actually playing the sport, improved the mood and physical function of Parkinson's disease in a new preliminary study.

While the study was small, and further research is needed, the results were encouraging.

In the 8-week study, 20 Parkinson's patients spent an hour playing the Wii three times a week for four weeks. They played Wii tennis, bowling and did a little virtual boxing. Players can do full body movements and see their progress on a screen.

"By the middle of the study, we actually had a number of people who could [defeat] their opponent out in the first round, which amazed us," said Dr. Ben Herz, program director and assistant professor in the School of Allied Health Sciences Department of Occupational Therapy.

Participants showed significant improvements in rigidity, movement, fine motor skills and energy levels, Herz said today at the fifth annual Games for Health Conference today in Boston. Perhaps most impressively, most participants' depression levels decreased to zero, he said.

Going in, each patient could walk well enough but had both sides of their body affected. Parkinson's is a degenerative disease that impairs motor skills. An estimated 45 percent of Parkinson's patients are reported to suffer from depression, though Herz suspects the actual figure is much higher.

His study was funded by a $45,000 grant from the National Parkinson's Foundation.

Studies have shown that exercise and video games independently can increase the production of dopamine, a neurotransmitter deficient in Parkinson's patients. He suspects that's the case with the Wii's exercise effect. Dopamine also helps improve voluntary, functional movements, which Parkinson's patients "use or lose," Dr. Herz says.

Next he plans to test the Wii Fit balance board with Parkinson's patients and expand his studies to multiple sites.

"Game systems are the future of rehab," Herz said. "About 60 percent of the study participants decided to buy a Wii for themselves. That speaks volumes for how this made them feel."