Cognitive Impairments Predict the Behavioral and Psychological Symptoms of Dementia

Abstract Background : To evaluate the association between behavioral and psychological symptoms of dementia (BPSD), as assessed via the Neuropsychiatric Inventory Questionnaire (NPI-Q), and cognitive impairments in individuals with dementia and amnestic mild cognitive impairment (aMCI). Methods: 120 participants, comprising of 80 aMCI and 40 Alzheimer’s disease (AD) subjects, were included in the study. aMCI was diagnosed using Petersen’s criteria, whilst AD was diagnosed using the National Institute of Neurological and Communicative Disorders and Stroke/AD criteria. Results: Pure exploratory bifactor analysis revealed that a general factor and a single-group factor (with high loadings on delusions, hallucinations, apathy, and appetite) underpinned the NPI-Q domains. Significant negative correlations between the Montreal Cognitive Assessment (MoCA) total score and the general and single-group NPI-Q scores were found in all subjects (aMCI + AD combined) and AD, but not in aMCI. Cluster analysis allocated subjects with BPSD (10% of aMCI and 50% of AD participants) into a distinct ‘AD + BPSD’ class. Conclusion: The NPI-Q total score, which is an appropriate index of BPSD, is largely predicted by cognitive deficits. It is plausible that aMCI subjects with severe NPI-Q symptoms (10% of our sample) may have a poorer prognosis and constitute a subgroup of aMCI patients who will likely convert into AD.