Thesis defense Anna Emmanouel (Donders series 253)
10 February 2017
Promotors: prof. Dr. L. Fasotti, prof. Dr. R. Kessels
Look at the frontal side of life. Anterior brain pathology and everyday executive function. Assessment approaches and treatment
“Executive function” (EF) is an umbrella term including a wide range of abilities such as goal setting, action planning, action initiation and maintenance, persistency of behaviour, inhibition, shifting, strategy formation, and updating and monitoring of information. Although a large number of studies has confirmed the frequency and variability of executive disorders after brain damage, issues relative to the anatomical localization of EF and its neuropsychological assessment need further clarification. In the recent past, core executive functions (EF) were traditionally related to frontal lobe pathology. However, executive tasks are complex and demanding and may include other non-frontal, more task-specific cognitive abilities (e.g. visual-spatial scanning). Secondly, traditional neuropsychological executive tests do not reflect the profile and severity of executive dysfunction in patients with moderate to severe traumatic brain (with mainly anterior pathology) in ‘open-ended’ activities of daily living. Recently, more ecologically valid executive tests have been developed These tests have not been systematically investigated for their sensitivity to anterior brain pathology, a matter with important clinical implications to the accurate assessment and rehabilitation of patients with traumatic brain injury.
Thus, the fist goal of this PhD. thesis was to explore the validity of several ecologically valid executive tests and questionnaires. The validity of the subtests of the Behavioural Assessment of the Dysexecutive Syndrome, that measure different executive domains, was investigated. We also examined the validity of the Dysexecutive-Questionnaire, a questionnaire aimed at assessing daily dysexecutive problems, and the Everyday Description Task (a task that demands the planning and description of everyday multistep activities), to accurately identify anterior brain damage.
Our results show that the majority of these instruments, mimicking or questioning real-life events, are sensitive and can discriminate patients with anterior lesions from those with posterior lesions. The first group exhibits significantly worse performance than the latter one, especially on tasks that demand action planning, intentionality and shifting. Consequently, our findings indicate a relation of daily executive dysfunction with mainly anterior pathology. This evidence can contribute to the planning and application of more adequate assessment protocols and cognitive treatment programs for patients with traumatic brain injury.
Our second goal was to explore the effectiveness of a new cognitive rehabilitation program, combining Goal Management Training and the Updating component of Working Memory. This combination was supposed to facilitate executively impaired brain-damaged patients in accomplishing multistep activities of daily living. Such activities demand a stepwise planning of actions, the updating and keeping track of the steps to-be-performed in sequence, as well as goal-directed behaviour. This new combined treatment and a control Working Memory Training program designed for other purposes, were separately applied in two patient groups with executive deficits. The patients were randomly assigned to each group, and matched for age and education. We found that after treatment, the patient group who had been administered the combined program performed significantly better on the majority of a series of outcome measures than the working memory training group. The effects of the new treatment were more evident in tasks that demanded action planning and a controlled, step-by-step execution of a task. Future research is recommended to replicate and confirm these results.