The Mild Behavioral Impairment Checklist for Parkinson's Disease: An Ancillary Instrument in Cognitive Assessment

Mild behavioral impairment (MBI) is a syndrome characterized by the later-life onset of neuropsychiatric symptoms (NPS) and serves as a potential marker for dementia. In Parkinson's disease (PD), MBI has been associated with worse cognition, cortical atrophy, and altered connectivity. Unlike existing instruments that assess NPS in PD, the MBI Checklist (MBI-C) leverages sustained behavioral changes to identify patients at risk of cognitive impairment and neurodegeneration. The 34-item MBI-C has yet to be validated in PD.

This study assesses the MBI-C's psychometric properties in a multicenter Canadian PD sample and proposes a revised version optimized for PD.

A total of 406 PD patients from the Canadian Open Parkinson Network were assessed with the MBI-C to investigate its construct validity. Additional evaluations, including the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Neuropsychiatric Inventory (NPI), and Montreal Cognitive Assessment (MoCA), were implemented to examine the concurrent and criterion validities of the checklist.

The original MBI-C exhibited considerable floor effects (24.9%). Exploratory factor analysis revealed a 5-factor 24-item MBI-C as consistent for PD (Cronbach's α = 0.856). All intrafactor correlations were statistically significant (P < 0.05), and convergent validity was found to be higher than divergent validity. Moreover, the MBI-C demonstrated moderate concurrent validity with the NPI (intraclass correlation coefficient [ICC]: 0.633, P < 0.001). The cutoff score associated with cognitive impairment on the revised instrument was 6|7.

Compared to the original version, the revised MBI-C exhibited enhanced psychometric properties for measuring MBI in PD. It also demonstrated acceptable specificity when related to cognitive impairment. Future psychometric research should focus on capturing the subtlest manifestations of MBI in PD, examining patient-caregiver concordance, and addressing predictive validity for cognitive decline.