Aims: To evaluate the psychometric attributes of the Scales for Outcomes in Parkinson's Disease-Psychosocial (SCOPA-PS) in Spain and to compare them with previous studies.
Patients and methods: We performed a multi-centre, cross-sectional study of 387 patients with Parkinson's disease (PD), 70% of whom were in Hoehn and Yahr (HY) stages 2 or 3, with a mean age of 65.8 +/- 11.1 years and 8.1 +/- 6 years' progression. The following measures were applied: SCOPA-Motor, SCOPA-Cognition, modified Parkinson's Psychosis Rating Scale, Clinical Impression of Severity Index for Parkinson's Disease (CISI-PD), Cumulative Illness Rating Scale-Geriatrics, SCOPA-Autonomic, SCOPA-Sleep, Hospital Anxiety and Depression Scale (HADS), Fatigue and Pain Visual Analogue Scales, EQ-5D and SCOPA-PS. Acceptability, internal consistence, dimensionality, construct validity and precision of the SCOPA-PS were analysed.
Results: The SCOPA-PS summary index displayed no ceiling or floor effect. Internal consistence was satisfactory (alpha = 0.85; item-total correlation => 0.39). Two factors were identified (53.5% of the variance). The SCOPA-PS was highly correlated (r(S) => 0.5) with the HADS, SCOPA-Motor, SCOPA-Automatic and EQ-5D index, and moderately so (r(S) = 0.35-0.49) with CISI-PD, fatigue and HY. The SCOPA-PS discriminated significantly between patients grouped according to HY stages, levels of severity of the CISI-PD, age groups and length of time with PD. The standard error of the measure was 7.24 +/- 18.7. As a whole, these findings are in agreement with previous studies.
Conclusions: The SCOPA-PS is a scale with a satisfactory degree of acceptability, and it is consistent, valid and precise for evaluating the psychosocial impact of PD.