A LONGITUDINAL-STUDY OF PARKINSONS-DISEASE - CLINICAL AND NEUROPSYCHOLOGICAL CORRELATES OF DEMENTIA

Neuropsychological assessments were performed in ninety-one de novo pa tients participating in the Sydney Multicentre Study of Parkinson's di sease. Assessments were made at baseline and after 3 and 5 years. Perf ormance at baseline and after 5 years was compared with controls, At b aseline 37% of patients whose symptoms of Parkinson's disease had begu n after the age of 70 years were demented. This compared with a preval ence of dementia of 8.8% in patients whose symptoms had begun before t he age of 70 years. By 5 years the prevalence of dementia in the two g roups had risen to 62.3% and 17.3% respectively, The death rate was hi gher over the 5 year period in the demented patients, Demented patient s had more symmetrical signs, higher disability and bradykinesia score s and more impairment of gait and balance at baseline than non-demente d patients, The presence of dementia at baseline predicted a poor resp onse to treatment. The dementia at baseline had features of a subcorti cal dementia. Subsequently, aphasia, apraxia and agnosia emerged, maki ng the dementia indistinguishable from that of Alzheimer's disease. Pa tients with well preserved cognitive function at baseline had a good r esponse to levodopa and were more likely to develop levodopa induced d yskinesia, These results show that the clinical features of Parkinson' s disease and response to treatment are influenced by the age of onset of symptoms and by the presence of dementia. (C) Pearson Professional 1996