The utility of the Mattis Dementia Rating Scale in Parkinson's disease mild cognitive impairment

Abstract

The Movement Disorders Society (MDS) recently proposed guidelines for diagnosis of mild cognitive impairment in Parkinson's disease (PD-MCI) that includes two assessment levels: abbreviated (Level I) and comprehensive (Level II). The aim of this study was to determine the utility of the Mattis Dementia Rating Scale (MDRS), a recommended Level I test, for detecting Level II PD-MCI diagnosis. The study sample included 30 patients diagnosed with PD-MCI based on Level II MDS criteria and 68 PD patients with normal cognition (PD-NC). Receiver operator curve (ROC) analyses were generated to measure the sensitivity and specificity of various MDRS cutoff scores. To examine the utility of the MDRS as a screening tool, the optimal cutoff point was defined as the lowest value providing ≥80% sensitivity. For use of the MDRS as a diagnostic tool, the optimal cutoff point was defined as the highest value providing ≥80% specificity. ROC analyses showed that the optimal MDRS cutoff score for screening purposes and diagnostic purposes were ≤140 and ≤137, respectively. However, an examination of sensitivity/specificity values for the screening cutoff scores suggested that a total score of ≤139 for screening purposes yielded a better balance between sensitivity (77%) and specificity (65%). In a clinical setting, in which detection of PD-MCI may be important, a total MDRS score of ≤139 can be used to detect PD-MCI. In research and other settings in which diagnostic certainty is more important, a score of ≤137 may be more useful.