Diagnostics and Ecological Validity of the Italian Version of the Parkinson's Disease Cognitive Rating Scale

This study aimed to assess the diagnostics and ecological validity of the Parkinson's Disease Cognitive Rating Scale (PD-CRS) within an Italian cohort of non-demented Parkinson's disease (PD) patients.

N = 128 non-demented PD patients were administered the PD-CRS, Montreal Cognitive Assessment (MoCA), and Parkinson's Disease Cognitive Functioning Rating Scale (PD-CFRS). Receiver-operating characteristic analyses were performed to explore the diagnostics of both raw and adjusted PD-CRS scores, by operationalizing the positive state as a below-cut-off MoCA score. Correlational analyses were run to test the ecological validity of the PD-CRS against the PD-CFRS.

Both raw and adjusted PD-CRS scores accurately identified patients with a defective MoCA scores (AUC = 0.84-0.85), yielding optimal diagnostics. A cut-off of <73.93, as identified on demographically adjusted PD-CRS scores, yielded the best diagnostics (sensitivity = 0.70; specificity = 0.89; positive and negative predictive values = 0.83 and 0.79; positive and negative likelihood ratios: 6.23 and 0.37: number needed for screening utility: 0.78). The PD-CRS was related to the PD-CFRS (r_s = -0.24; p = 0.018).

The Italian PD-CRS is a diagnostically sound and ecologically valid screener for cognitive impairment in non-demented PD patients.