The relationship between executive functioning and independent living skills in mild cognitive impairment and mild dementia

Executive functioning refers to those capacities (e.g., initiation, planning, self-monitoring) that enable a person to engage successfully in complex, purposeful, and everyday tasks. Decreases in executive functioning have been identified early in dementia and are related to impairments in instrumental activities of daily living. The purpose of the research was to examine changes in neuropsychological functioning early in dementia and determine whether performance on measures of executive functioning could predict objective (Independent Living Scales; Loeb, 1996) and subjective (Lawton IADL; Lawton & Brody, 1969) measures of instrumental activities of daily living. Severity of cognitive impairment was based on the Clinical Dementia Rating scale (CDR; Hughes, Berg, Danziger, Coben, & Martin, 1982) and included a normal control group (CDR = 0; n = 28; mean age = 71.0 years), a mild cognitive impairment group (CDR = 0.5; n = 30; mean age = 76.9 years), and a mild dementia group (CDR = 1; n = 26; mean age = 79.8 years).; The MCI group demonstrated memory impairment compared to normal controls, but performed significantly better than those with mild dementia. The MCI group also demonstrated impairments in executive functioning, visuospatial abilities, information processing speed, and overall IADL abilities. Measures of executive functioning predicted IADLs, even after other cognitive variables were entered into the regression first. The Frontal Assessment Battery (FAB), Trail Making Test - Version B (TMT-B), and Frontal Systems Behaviour Scale Executive Dysfunction (FrSBe ED) accounted for 56 and 49% of the variance in the Independent Living Scales and Lawton IADL, respectively. When the normal control group was removed, the FAB, STROOP, and FrSBe accounted for 52% of variance in ILS scores, while the FrSBe and FAB accounted for 28% of variance in the Lawton IADL ratings. This study adds to the research literature supporting the relationship between executive functioning and functional abilities in older adults with MCI and mild dementia.