title: Color vision in Parkinson's disease and essential tremor.
abstract: OBJECTIVE
  Decreased visual function is one of the non-motor dysfunctions of Parkinson's disease (PD). Recent evidences suggest that essential tremor (ET) is not 'pure' motor disorder and there is growing evidence that this disease is a multiple-system disorder. In some cases, it is difficult to differentiate ET from PD. In addition, there is considerable controversy regarding the relationship between PD and ET. The objective of this study was to compare color discrimination dysfunction amongst patients with PD and ET and to investigate the clinical relevance.
  
  
  METHODS
  Case-control comparisons of 54 patients with PD, 36 patients with ET, and 34 age-matched controls were performed. All cases underwent Farnsworth-Munsell 100 Hue test (FMT) and clinical assessments on medication. In addition, the association between color vision abnormalities and motor handicaps was investigated.
  
  
  RESULTS
  There were significant differences in the total error scores (TES) of the FMT amongst the three groups; patients with the PD had higher TES than the patients with ET and the controls after adjustments for age. In addition, the motor symptom severity in PD correlated with the FMT abnormalities, especially with regard to the axial symptoms.
  
  
  CONCLUSIONS
  The results of this study suggest that color vision abnormalities may be one of the non-motor clinical characteristics of PD-related dysfunction in contrast to ET. In addition, the severity of axial motor symptoms was closely related to visual dysfunction. Confirmation of these findings as well as the mechanisms underlying these results requires further study.
authors: Department of Neurology, The Catholic university of Korea, Seoul St Mary's Hospital, Seoul, South Korea.
authors: Y-S
authors: YS
authors: Oh
authors: J-S
authors: JS
authors: Kim
authors: S-W
authors: SW
authors: Chung
authors: I-U
authors: IU
authors: Song
authors: Y-D
authors: YD
authors: Kim
authors: Y-I
authors: YI
authors: Kim
authors: K-S
authors: KS
authors: Lee
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003117:Color Vision Defects / Q000209:etiology*; D020329:Essential Tremor / Q000150:complications* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D010300:Parkinson Disease / Q000150:complications* / Q000503:physiopathology