Differences in physical function across dementia subtypes and cognitive decline: a cross-sectional study

Cognitive impairment significantly affects physical function in dementia patients, but variations across dementia types and levels of cognitive decline remain unclear. This retrospective cross-sectional study included 874 patients (80.75 ± 8.00 years; 60.4% female) with different dementia types and cognitive impairment levels. Six physical function tests were administered: the De Morton Mobility Index (DEMMI), 6-minute walking test (6MTW), 10-meter walking test (10MWT), hand grip strength (HGS), 30-second chair stand (30sSTS), and the timed "Up & Go" test (TUG). Cognitive function was assessed using the Mini-Mental State Examination (MMSE). The Mild Cognitive Impairment (MCI) group outperformed Alzheimer's Dementia (AD) and Vascular Dementia (VaD) on DEMMI, 30sSTS and HGS (p < 0.001, η² = 0.012 to 0.052). Differences in the 6MWT were significant in ANOVA but disappeared after adjusting for sex and age (p = 0.066). Severe cognitive impairment was linked to significantly lower physical performance across all measures (p < 0.001, η² = 0.037 to 0.064). Physical function profiles vary by dementia type and cognitive decline level, highlighting the need for targeted interventions to address specific physical challenges.