A brief scale for the dementia of Parkinson's disease

The lack of standardized criteria and methodologies to assess dementia in patients with Parkinson's disease has resulted in inconsistencies and controversies in the literature regarding the incidence and basis of this condition. The authors examined a large group of patients with Parkinson's disease using two standardized sets of criteria for dementia. The neuropsychological data obtained was analyzed using stepwise discriminant analysis, and a brief scale was developed. The results indicated that a regression equation derived from just three neuropsychological procedures (which take only 10 minutes to administer) provides maximum discrimination between patients originally classified as demented or non-demented according to standardized criteria. Cut-off values for the product of the regression equation were calculated to accurately and reliably classify patients using the brief scale.