Tremor at onset. Predictor of cognitive and motor outcome in Parkinson's disease?

We examined 46 male patients with idiopathic Parkinson's disease to see whether tremor at onset was as useful a predictor of benign clinical outcome as tremor predominance after several years. When we compared patients with tremor at onset (n = 27) with those whose disease began with brady-kinesia/rigidity (n = 9), or gait disorder (n = 10), we found no significant differences after a mean of 7 years in motor, cognitive, or affective status. Sixteen of the tremor-onset patients continued to have tremor predominance with minimal gait disorder after about 7 years. These tremor-predominant patients had significantly better motor outcome and somewhat better cognitive outcome than either tremor-onset patients who subsequently developed gait disorder (n = 11) or patients without tremor at onset (n = 19). Tremor predominance after several years appears to be a better predictor of a benign clinical course of Parkinson's disease than tremor at onset.