Executive dysfunction in early Alzheimer's disease.
Twenty five patients with probable mild Alzheimer's disease were assessed for deficits in executive functioning and the impact of these deficits on performance in other neuropsychological domains. The Wisconsin card sorting test, the release from proactive interference paradigm, the verbal fluency test, and the Stroop test were adopted to classify patients with (AD+) and without (AD-) executive deficits. Seven of the patients showed an impairment in executive function (AD+), defined as a performance below the cut off score in at least two of these tests. There were no significant differences in clinical assessments, demographic features, or other cognitive functions between patients. Executive dysfunction may be an early additional feature in a subgroup of patients with mild Alzheimer's disease. Impairment on frontal lobe tests does not seem to be related to the severity or duration of disease, or to a different pattern of impairment in other cognitive domains.