Parkinson's Disease‐Cognitive Rating Scale (PD‐CRS): Normative Data and Mild Cognitive Impairment Assessment in Brazil

Abstract

AbstractBackgroundThe Parkinson's Disease‐Cognitive Rating Scale (PD‐CRS) assesses posterior‐cortical and frontal‐subcortical cognitive functioning and distinguishes mild cognitive impairment in Parkinson's disease (PD‐MCI); however, it was not evaluated in Brazil.ObjectivesTo investigate PD‐CRS's reliability, validity, normative data, and accuracy for PD‐MCI screening in Brazil.MethodsThe effects of age, education, and sex on PD‐CRS scores were explored. The instrument was tested in 714 individuals (53% female, 21–94 years), with a broad range of education and no neurodegenerative disorder. Trail Making, Consonant Trigrams, Five‐Point, and semantic fluency tests were administered for comparison. A second study enrolled patients with PD and intact cognition (n = 44, 59.75 ± 10.79 years) and with PD‐MCI (n = 25, 65.76 ± 10.33 years) to investigate criterion validity. PD‐CRS subtests were compared with the Cambridge Automated Neuropsychological Battery memory and executive tasks.ResultsPD‐CRS was unidimensional and reliable (McDonald's ω = 0.83). Using robust multiple regressions, age, and education predicted the total and derived scores in the normative sample. At the 85‐point cutoff, PD‐MCI was detected with 68% sensitivity and 86% specificity (area under the curve = 0.870). PD‐CRS scores strongly correlated with executive and verbal/visual memory tests in both normative and clinical samples.ConclusionsThis study investigated the applicability of PD‐CRS in the Brazilian context. The scale seems helpful in screening for PD‐MCI, with adequate internal consistency and construct validity. The PD‐CRS variance is influenced by age and educational level, a critical issue for cognitive testing in countries with educational and cultural heterogeneity.