Demonstration of cognitive decline in Parkinson's disease using the Cambridge Cognitive Assessment (Revised) (CAMCOG-R)

Background Cognitive impairment is well recognised in Parkinson's Disease (PD) but few studies have examined cognitive decline over time in such subjects. Standard clinical assessments of cognitive function, such as the MMSE, do not measure all cognitive domains and often have a ceiling effect. CAMCOG-R provides a more comprehensive cognitive assessment allowing several different domains of cognition to be compared. It also features the ability to test 'executive function'. CAMCOG-R has only been reported on one previous occasion in PD subjects and this is the first study to report a follow-up CAMCOG-R to assess cognitive decline. Methods In a previously published study CAMCOG-R was administered to a prevalent community-based population of 94 subjects with PD with a MMSE of 25 or above. In this subsequent study 85 of the subjects (two declined and seven were deceased) underwent a follow-up CAMCOG-R after a mean delay of 13.1 months. Results The initial, and follow-up mean total CAMCOG-R scores were 88.65/104 and 84.75/104 respectively, demonstrating a significant decline (p < 0.05). Significant cognitive decline (p < 0.05) was also seen across every CAMCOG-R cognitive domain and in the executive function scores. Conclusions A wide range of cognitive ability was again demonstrated using CAMCOG-R in this PD population. The decline of 3.9 CAMCOG-R points over the 13-month period compares to other previous studies showing an annual decline of 1.6 CAMCOG points in normal elderly individuals and 12 CAMCOG points annually in those with established dementia. This study suggests that CAMCOG-R is a useful and appropriate tool for use in follow-up cognitive screening in PD subjects. Copyright (c) 2006 John Wiley & Sons, Ltd.