From mild behavioral impairment-checklist (MBI-C) to MBI-distress (MBI-D): a paired assessment and clinical correlates of domain-specific caregiver distress in MCI due to AD.

BACKGROUND: Mild behavioral impairment (MBI) captures later-life onset neuropsychiatric symptoms (NPS) that may herald neurodegeneration. The emotional impact of these early behavioral changes on caregivers is under-measured in pre-dementia care. OBJECTIVE: To develop a brief, domain-aligned caregiver distress scale for MBI (MBI-D) and examine clinical correlates of MBI-related caregiver distress in mild cognitive impairment due to AD (MCI-AD). METHODS: One hundred and four participant-informant dyads with MCI-AD at a Greek memory clinic were included. Caregivers completed the Greek MBI-C and the new five-item MBI-D (one item per ISTAART-AA MBI domain). Internal consistency (Cronbach's α), non-parametric tests, and Spearman correlations assessed bivariate associations. Multiple linear regression identified independent correlates of MBI-D total. Prespecified covariates were age, education, sex, global cognition (MMSE or ACE-R), disease duration, and MBI-C (total or domains). RESULTS: Internal consistency of the MBI-D was moderate (α = 0.617; standardized α = 0.627; mean inter-item r = 0.25). MBI-D total correlated strongly with MBI-C total (ρ = 0.789, p < 0.001), and each MBI-D domain correlated with its corresponding MBI-C domain (ρ = 0.478-0.850, all p < 0.001). Disease duration was associated with MBI-D total and with apathy-related distress (ρ = 0.302, p = 0.002 and ρ = 0.392, p < 0.001, respectively). In multivariable regression, MBI-C total and education were independent predictors of MBI caregiver distress (β = 0.804, p < 0.001, and β = 0.135, p = 0.017, respectively). In the MBI-C domains model, impulse dyscontrol, apathy and emotional dysregulation independently related to higher distress (B = 0.513, β = 0.482, p < 0.001, B = 0.315, β = 0.278, p < 0.001, and B = 0.289, β = 0.227, p = 0.001 respectively), while cognitive performance (MMSE and ACE-R) did not have a significant impact. CONCLUSION: The MBI-D, strongly coupled with MBI-C, is a concise, clinically practical and scalable measure of MBI-related caregiver distress in MCI-AD, capturing both symptom burden and domain-specific distress in a single administration. Impulsivity, apathy, and affective dysregulation are highlighted as priority targets for early, caregiver-focused interventions advancing innovative, prevention-oriented dementia care delivery.