Aim: To assess cognitive function in elderly subjects with clinically probable Parkinson's disease (PD).
Methods: A community sample of 126 patients with probable PD completed the CAMCOG, which is the cognitive section of the Cambridge Examination for Mental Disorders, and the Mini-Mental State Examination (MMSE). The performance of the CAMCOG and the MMSE in detecting dementia in this subject group was compared with the results of applying the DSM-IV criteria for dementia to this population.
Results: A total of 44% of the group met DSM-IV criteria for dementia, which is higher than most previous prevalence figures for dementia in PD. The CAMCOG was more sensitive than the MMSE in detecting cognitive impairment and more specific than the MMSE in detecting dementia as defined by DSM-IV criteria. Poorer performance on the CAMCOG was related to gender, social class and age (P<0.05). Among subjects with PD, those with dementia, as defined by DSM-IV criteria, were significantly older, had greater depressive symptomatology and had greater motor deficits. A greater proportion of the group with dementia were living in residential care (P<0.05).
Conclusion: The CAMCOG appears to be a useful screening instrument for dementia and cognitive impairment in PD. Furthermore, it may prove helpful in detecting those with PD who may be at risk of developing dementia and in longitudinal studies of cognitive function in PD.