Patterns of ADL and IADL independence across MMSE score ranges in Alzheimer's disease, dementia with Lewy bodies, and frontotemporal dementia: A cross-sectional analysis of a memory-clinic cohort.

BACKGROUND: Domain-level ADL and IADL independence across MMSE score ranges has been less well described in Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD). This study described the observed proportions of basic ADL and IADL independence across MMSE score ranges in these three neurodegenerative dementias. METHODS: In a cohort of 650 patients (524 AD, 90 DLB, 36 FTD), cognitive function was assessed with the Mini-Mental State Examination (MMSE), and daily function was evaluated using the Physical Self-Maintenance Scale and the Lawton IADL scale. Patients were grouped into MMSE score ranges. For each diagnosis and MMSE score range, we calculated the observed proportion of participants rated as independent in each ADL/IADL domain and Wilson score 95% confidence intervals. Because the FTD sample was small (n = 36), with only 1-11 participants in individual five-point MMSE score ranges, and several MMSE-specific subgroup counts were sparse, the analyses were descriptive. RESULTS: Observed independence proportions varied across ADL/IADL domains, MMSE score ranges, and diagnostic groups. In AD and DLB, shopping, food preparation, and medication management had low observed independence proportions even in higher MMSE ranges. In the MMSE 21-30 stratum, selected absolute numerical contrasts between DLB and AD ranged from 7.2 percentage points for feeding to 18.4 percentage points for bathing. Estimates for FTD, which were based on only 1-11 participants per five-point MMSE score range, and for DLB in the MMSE 0-10 stratum were based on small denominators and were therefore imprecise. CONCLUSIONS: This study provides descriptive estimates of domain-level ADL and IADL independence across MMSE score strata in AD, DLB, and FTD. The results may contribute to domain-specific assessment and support planning for people living at home with MCI or dementia. These findings should be regarded as hypothesis-generating for future studies.