Psychometric properties of the Italian version of the Scales for Outcomes in Parkinson's disease- Cognition (SCOPA-Cog).

The Scales for Outcomes in Parkinson’s disease-Cognition (SCOPA-Cog) has been shown to be a clinimetrically rigorous and valid instrument for a disease-oriented neuropsychological assessment of Parkinson’s disease (PD) patients. In the present study we evaluated the psychometric properties of the Italian version of the SCOPA-Cog in 121 PD patients. The scale explores memory, attention, and executive and visuospatial functions and takes approximately 20 minutes to administer. Data distribution (skewness= -0.23) and internal consistency (Cronbach’s alpha= 0.78) were satisfactory. Standard error of measurement was 3.42. The outcome was significantly worse in patients with an abnormal Psychometric properties of the Italian version of the Scales for Outcomes in Parkinson’s disease-Cognition (SCOPA-Cog) score on the Dementia Rating Scale (DRS) (SCOPA-Cog mean score 14.6±5.1 out of a total of 43) with respect to cognitively intact subjects (24.2±4.3)(p<0.0001). The DRS showed good convergent validity (Spearman rho= 0.77, p<0.0001), and a high coefficient of variation (= 0.34). These findings support the goodness of the Italian SCOPA-Cog in terms of metrics and validity.