Reliability, validity, and diagnostic accuracy of Parkinson's Disease-Cognitive Rating Scale in Iranian patients with idiopathic Parkinson's disease

Purpose To investigate the reliability and validity of Parkinson's Disease-Cognitive Rating Scale (PD-CRS) in Iranian patients with idiopathic PD. Methods One hundred and eighty patients with PD and 60 age-, gender-, and educational level-matched healthy individuals participated in this study. Inter-rater and test-retest reliability of the Persian version of PD-CRS was investigated in 80 patients with PD. To evaluate the construct validity of the PD-CRS, its correlation with the Scales for Outcomes in Parkinson's disease-Cognition (SCOPA-Cog), Mini-Mental State Examination, Montreal Cognitive Assessment, Clock Drawing Test, Unified Parkinson's Disease Rating Scale-Section I, and Quick Dementia Rating System was assessed. To assess the diagnostic accuracy of the PD-CRS, patients with PD were classified as groups with normal cognitive function, mild cognitive impairment (MCI), and dementia using the Clinical Dementia Rating. Results Test-retest and inter-rater reliability (ICC > 0.90), as well as internal consistency (alpha = 0.94) of the Persian version of PD-CRS, were excellent. A high positive correlation was found between the PD-CRS and SCOPA-Cog. A cut-off point of <= 79 (sensitivity 98.15% and specificity 98.04%) and <= 62 (sensitivity 100%, and specificity 100%) on the PD-CRS total score was obtained for detecting MCI and dementia in PD patients, respectively. Conclusions The results of this study showed that the Persian version of PD-CRS is a reliable and valid measure with high sensitivity and specificity to identify MCI and dementia in patients with PD.

Automated summary

The aim of this study was to investigate the reliability and validity of the Parkinson's Disease-Cognitive Rating Scale (PD-CRS) in Iranian patients with idiopathic Parkinson's disease (PD). The Persian version of PD-CRS showed excellent test-retest and inter-rater reliability, as well as internal consistency. It also exhibited high sensitivity and specificity in identifying mild cognitive impairment (MCI) and dementia in PD patients. Overall, the Persian version of PD-CRS is a reliable and valid measure for assessing cognitive function in patients with PD.