Abstract
INTRODUCTION: Cognitive impairment is a common non-motor feature of Parkinson's Disease (PD). Diagnosis of mild cognitive impairment is challenging and routinely missed in clinical practice. Our study aimed to study the efficacy of NIMHANS Neuropsychological Battery for Elderly (NNB-E) in diagnosing subtle cognitive deficits in PD patients. OBJECTIVE: The aim of this study is to validate NNB-E and evaluate cognitive impairment in PD patients in comparison with healthy controls. METHODS: We recruited 31 PD patients and 31 healthy controls in the current study. We validated NNB-E using receiver operating characteristic (ROC) curve analysis, Crohnbach's alpha, principal component analysis, and Pearson product-moment correlation, and studied the cognitive impairments using NNB-E in the non-demented PD patients and controls who scored ≥24 on HMSE. RESULTS: Cognitive performance of PD patients was poor compared to controls. NNB-E showed good internal consistency and construct validity with Crohnbach's alpha of 0.861 and area under the curve (AUC) of 0.878. The battery was able to detect mild cognitive impairment in 74.1% of patients and 6.4% of controls. The ROC curve showed that the overall sensitivity of the battery was 73.2% and specificity was 92.6% at an optimal cutoff score. Different cutoff values set for defining PD-MCI as per MDS task force criteria resulted in varying frequencies of MCI ranging from 25.8% to 71%. CONCLUSION: Our study established the validity of NNB-E in PD patients, and this tool was suitable for diagnosing PD-MCI and discriminating PD patients from normal controls in the Indian population. This study also showed PD-MCI at various cutoff scores with greater impairment in executive and attention domains.