Instrumental Activities of Daily Living in Neurocognitive Disorders: Determinants and Clinical Implications for Health Promotion

Background/Objectives: Instrumental Activities of Daily Living (IADL) are key indicators of autonomy and functional ability in older adults with neurocognitive disorders (NCDs). Their performance is influenced by cognitive, motor, and psychosocial factors. However, specific predictors of IADL performance across the NCD spectrum is less well-characterized. This study aimed to identify cognitive, motor, and caregiver-related determinants of IADL in individuals with minor and major NCDs. Methods: A cross-sectional study was conducted in 117 participants referred from a university dementia clinic. Standardized tools for IADL (Lawton IADL Scale), cognition [Addenbrooke’s Cognitive Examination III (ACE-III)], Functional Cognitive Assessment Scale (FUCAS)], motor functions, balance, and mobility [Tinetti Test, Timed Up and Go (TUG)], emotional status [Geriatric Depression Scale (GDS)], neuropsychiatric symptoms [Neuropsychiatric Inventory (NPI)], and caregiver burden [Zarit Burden Interview (ZBI)] were administered. Multiple regression analyses were performed to identify predictors of IADL score. Results: In the total sample (n=117), IADL performance was significantly predicted by ACE-III, FUCAS, and Tinetti-balance, explaining 75.1% of IADL variance. In minor NCD group (n=41), IADL performance was predicted by FUCAS, Tinetti-balance, and ZBI (adjusted R² =0.697). In major NCD group (n=76), ACE-III, FUCAS, Tinetti-balance, and disease duration were significant predictors (adjusted R²=0.673). For all models, worse profile on the previous variables predicted impaired IADL. Conclusions: Global cognitive decline, executive dysfunction in everyday problem-solving situations, balance impairment, and caregivers’ burden are critical determinants of IADL in NCDs. Comprehensive assessments and multidisciplinary interventions, including caregiver support, are essential for health promotion by preserving autonomy and functional independence in older adults.