Impact of dysexecutive syndrome on autonomy in early Alzheimer's disease and Mild cognitive impairment

Abstract

Early impairment of the cognitive and behavioral executive processes are found in Mild Cognitive Impairment (MCI) as well as in Alzheimer's disease (AD). These processes are strongly linked to autonomy in daily living because they are involved in our adaptation to many new situations. To evaluate the executive processes and their links with autonomy, we compared 20 control subjects to 20 patients with MCI, and 20 patients with early AD. All participants completed three executive cognitive task, according to the Miyake's model: set-shifting was assessed by the Trail Making Task, inhibition control by the Hayling test, and working memory by the Updating test. They also completed the Lille Apathy Rating Scale (Lars) evaluating four components of apathy. The autonomy, conceptualized as competency in four domains of daily-living, was evaluated by the Patient Competency Rating Scale (PCRS), completed by a close relative. Control subjects showed higher scores than both clinical groups on the TMT time completion. AD group showed a tendency to make more errors than the control subjects on Hayling test, whereas MCI group didn't differ from the other groups. No other group effect was found on the executive dependent variables. Both MCI and Alzheimer groups had higher scores of apathy than the control group on the Lars total score and its three components. Similar results were found on the PCRS and the Lars three subscales. The best predictors of autonomy were the TMT time completion and the total Lars score. Loss of competency is found in MCI as well as in AD and is correlate to set-shifting and apathy.