Parkinson's Disease—Cognitive Functional Rating Scale across different conditions and degrees of cognitive impairment

Abstract

Background/aimsThe Parkinson's Disease—Cognitive Functional Rating Scale (PD-CFRS) was designed to avoid motor biases in capturing the functional impact of cognitive impairment in Parkinson's disease (PD). Its performance capturing functional impairment in other conditions leading to cognitive dysfunction is unknown. We compare it with non-specific Instrumental Activities of Daily Living scales. MethodsTwo hundred consecutive patients diagnosed in a community hospital with mild cognitive impairment (MCI) [31 MCI-amnestic; 33 MCI-multi-domain; 33 PD-MCI] and dementia [35 Alzheimer's disease; 34 vascular dementia; 34 PD with dementia] were assessed on the PD-CFRS, the Blessed Dementia Scale (BDS), the Clinical Dementia Rating — Sum of Boxes (CDR-SOB), and given a comprehensive cognitive assessment. Diagnostic accuracy and optimal cut-off scores were calculated for the PD-CFRS and compared with each functional measure. ResultsThe PD-CFRS presented high concurrent validity and significant correlation with both BDS and CDR-SOB, and cognitive scores offering a similar discrimination accuracy to non-specific scales [PD-CFRS≥9 (sensitivity=0.94; specificity=0.95)]. No changes appear in cut-off scores when excluding PD patients. Effect size analysis indicated no relevant interference with PD-CFRS scores between the principal cognitive subgroups. DiscussionThe findings extend the clinimetric properties of the PD-CFRS and indicate it as an adequate instrument to capture the full spectrum of functional consequences of cognitive decline in the community.