Metric Properties of the Mini-Mental Parkinson and SCOPA-COG Scales for Rating Cognitive Deterioration in Parkinson's Disease

Parkinson's disease (PD) is a chronic neurodege- nerative disorder that causes cognitive impairment and de- mentia in � 30% of patients. Objective: Compare metric qual- ities of Mini-Mental Parkinson (MMP) and scales for out- comes in Parkinson's disease-cognition (SCOPA-COG) with respect to their relative reliability, validity and ability to pre- dict symptoms (mobility, quality of life, social repercussions, and mood) in PD patients. Outpatients (n5123, 78 males/45 females) diagnosed with PD were included in the study. A multilevel (hierarchical) modeling analysis was performed along with tests of reliability and validity to ascertain which of the two models better predicts symptoms related to PD. Results: The MMP differed significantly between patients with Hoehn and Yahr (H&Y) stages 1, 2 or versus 4/5 (grouped together). The SCOPA-COG showed differences only between patients in H&Y stages 2 versus 4/5. Both scales were dependent on educational background and age. The SCOPA-COG had a higher coefficient of variation (0.303) than the MMP (0.184), indicating that it was the more discriminative of the two. Conclusions: The SCOPA- COG has some advantages over the MMP, the most impor- tant being a greater discriminative ability. Multilevel hier- archical analysis clarified the necessity of stratifying the PD population according to educational background, years of ill- ness, and H&Y stage when using these scales. � 2010 Movement Disorder Society