Psychometric attributes of the SCOPA-COG Brazilian version

Abstract

Cross-cultural adaptation and independent psychometric assessment of the Scales for Outcomes in Parkinson's disease-Cognition (SCOPA-COG), Brazilian version was performed. Parkinson's disease (PD) patients were evaluated by means of the SCOPA-Motor scale, Hoehn and Yahr staging (HY), Clinical Impression of Severity Index-PD (CISI-PD), Parkinson Psychosis Rating Scale, and Hospital Anxiety and Depression Scale. Cognition was evaluated using the Mini-Mental State Examination (MMSE), Short Portable Mental Status Questionnaire (SPMSQ), and SCOPA-COG. The following attributes were explored: acceptability, scaling assumptions, reliability, precision, and construct validity. One hundred fifty-two patients were assessed (mean age, 63.2 years; disease duration, 7.8 years; median HY stage, 3). Mean SCOPA-COG and MMSE were 18.2 and 25.7, respectively. The internal consistency of the SCOPA-COG (Cronbach's alpha = 0.81; item-total correlation, 0.38-0.62) was satisfactory. While the intraclass correlation coefficient value was 0.80, weighted kappa ranged from 0.30 (dice task) to 0.72 (animal fluency task). The standard error of measurement value for the SCOPA-COG was 3.2, whereas the smallest real difference was 8.9. SCOPA-COG total scores significantly decreased as the HY stage increased (Kruskal-Wallis, P < 0.0001). Age, years of education, and PD duration (all, P < 0.001) were observed to have an independent, significant effect on the SCOPA-COG. The SCOPA-COG is a short, reliable, valid instrument that is sensitive to cognitive deficits specific to PD. © 2007 Movement Disorder Society.