Distorted color discrimination in 'de novo' parkinsonian patients

We performed the Farnsworth-Munsell 100-hue test in 16 "de novo" patients with Parkinson's disease and 16 age-matched controls to determine their color discrimination ability. The mean total error score in patients was significantly elevated as compared with controls (64.6 in patients versus 16.0 in controls). We conclude that the impairment of color discrimination may be an early sign in Parkinson's disease.