FRIDAY, Oct. 7 (HealthDay News) -- A patient's ability to ride a bicycle can help doctors determine whether the patient has Parkinson's disease or atypical parkinsonism, regardless of the terrain or riding situation, a new study indicates.

Atypical parkinsonism includes disorders that appear similar to Parkinson's disease but respond differently to treatment. It was already known that patients with atypical parkinsonism lose the ability to cycle early in their illness, while Parkinson's patients can still ride well.

But it wasn't known if this "bicycle sign" was universally applicable across the varieties of riding environments or situations in different countries.

In this study, Japanese researchers assessed the reliability of the "bicycle sign" in their country, which has hilly, narrow roads crowded with cars. They found that 88.9 percent of Japanese patients with atypical parkinsonism stopped cycling during the first few years of their illness, compared with 9.8 percent of Parkinson's patients.

They compared this to the bicycle-friendly Netherlands, where 51.5 percent of patients with atypical parkinsonism stopped cycling early in their illness. The difference may be due to the fact that cycling is much more difficult in Japan.

The study was published Oct. 6 in the Journal of Parkinson's Disease.

"Although bicycling cultures may differ between countries, it is possible that the 'bicycle sign' could contribute to earlier and better differential diagnosis of parkinsonism during the diagnostic interview. When we see patients with parkinsonism without a definitive diagnosis, it is a simple thing to ask the question, 'Can you still ride a bicycle?'" Hideto Miwa, of the neurology department at Wakayama Medical University, said in a journal news release.

More information

The U.S.-based National Parkinson Foundation outlines the different types of atypical parkinsonism.