Parkinson Study Group Cognitive/Psychiatric Working Group. A recommended scale for cognitive screening in clinical trials of Parkinson's disease

Since cognitive impairment is common in Parkinson’s disease, particularly during advanced stages, there is a clear need for a standard but brief screening measure for use in clinical trials where cognition is not the primary outcome. In the present study, the authors conducted a systematic literature search for cognitive assessments previously used in Parkinsonian patients, and scales were then evaluated for there ability to screen for cognitive deficits, brief administration time (<15 minutes) and potential to discriminate subtle cognitive impairments. Only 5 scales could be identified, and the Montreal Cognitive Assessment (MoCA) appeared to be the most suitable. Widespread adoption of a single scale such as the MoCA in clinical trials will enable comparison between individual studies on Parkinson’s disease.