Functional ability in executive variant Alzheimer's disease and typical Alzheimer's disease

Abstract

A frontal, or executive, variant of Alzheimer's disease (EAD) has been described in the literature in which frontal dysfunction accompanies temporal and parietal changes in the early stages of the illness. However, no study has empirically investigated associated aspects, such as neuropsychiatric symptoms, instrumental activities of daily living, or caregiver burden in this EAD subgroup. We compared the performance of two subgroups of mild Alzheimer's disease patients (e.g., EAD and typical Alzheimer's disease; TAD) on neuropsychological and associated measures. Results revealed that the EAD group, selected based on poor executive scores, did not significantly differ from the TAD group on nonexecutive neuropsychological tests of intelligence, language, verbal and nonverbal memory, or visual-spatial abilities. However, the EAD group evidenced more severe neuropsychiatric symptoms, impaired activities of daily living, and greater caregiver distress than the TAD group. Thus, the EAD subgroup is characterized by executive dysfunction, neuropsychiatric symptoms, and functional disability in excess of that seen in TAD. Whether our EAD subgroup represents an actual frontal variant of Alzheimer's disease awaits replication in a larger sample including neuroimaging and pathological confirmation, as well as longitudinal assessment of cognition and neuropsychiatric symptoms.