An Estimate of the Prevalence of Dementia in Idiopathic Parkinson's Disease

R. Mayeux, Y. Stern, R. Rosenstein, K. Marder, A. Hauser, L. Cote, S. Fahn
1988 Archives of Neurology  
\s=b\A review of the records for evidence of dementia using criteria adapted from the third edition of the Diagnostic and Statistical Manual of Mental Disorders in every patient (hospitalized and outpatient) with parkinsonism at a major medical center during an 18-month period revealed an overall prevalence of 10.9% in 339 patients with idiopathic Parkinson's disease. Demented patients were older, had a later age at onset of motor manifestations, and a more rapid progression of physical
more » ... of physical disability than nondemented patients. Duration of illness and levodopa use and the presence of tremor or depression were similar in demented and nondemented patients. Demented patients more often responded poorly or developed adverse effects to levodopa than nondemented patients. When Parkinson's disease began after age 70 years, dementia was noted over three times more frequently than when the disease began at an earlier age. The age-specific prevalence rate of dementia for patients older than 70 years was more than twice that for younger patients. Moreover, the number of records with evidence for dementia with idiopathic Parkinson's disease was 3.75 times greater than expected in comparison with data from a study of the prevalence of dementia in the elderly. {Arch Neurol 1988;45:260-262) T^he prevalence of dementia in Par¬ kinson's disease (PD) is unsettled; estimates range from 14% to 40%.' Brown and Marsden2 reviewed 17 studies reported over the last 60 years that included a total of 2530 patients with PD. Thirty-five percent of these patients had some degree of dementia, but the prevalence of dementia could have been overestimated because of sampling variability and differences in criteria used for the diagnosis of dementia or idiopathic PD. To estimate the frequency of dementia in PD, we reviewed the records of over 422 patients with parkinsonism from an urban hospital population, using standardized re¬ search criteria for dementia and idio¬ pathic PD. Of the records with suffi¬ cient evidence to warrant a diagnosis of dementia, 10.9% of the 339 patients with idiopathic PD were demented. Compared with a data set from a standard population of elderly adults older than 60 years, the odds of devel¬ oping dementia appear to be almost four times greater for patients with idiopathic PD.3 SUBJECTS AND METHODS We reviewed the records of every patient (hospitalized or outpatient) with parkinsonism in a major teaching hospital seen on all services during the 18 months between March 1, 1983, and Sept 30, 1984. The population included both private and clinic patients. Although the hospital is a tertiary care institution, 90% of the patients came from the greater New York area and were followed up annually. The population was representative of a large urban hospital-based cohort. When a patient had more than one visit (hospital and/or outpatient visits) during the study period, only the first encounter was used in estimating the prevalence of dementia. All available information, including that from subsequent chart entries, was used to sub¬ stantiate a diagnosis regardless of when it was recorded, however.
doi:10.1001/archneur.1988.00520270034017 pmid:3341950 fatcat:qmr4ay6axbewldz636o265e4ka