| Summary: | There are typical neuropsychological sequelae associated with brain injury, (particularly traumatic brain injury), including executive impairment, sometimes termed the 'dysexecutive syndrome'. Executive problems have been related to poor psychosocial outcome, and are thus important to identify to inform rehabilitation. There is an increasing demand to ascertain the ecological validity of neuropsychological tests to predict how impairment will impact on everyday functioning. The neuropsychological testing of executive functioning, however, is very difficult, due to its complex nature, and attempts to design meaningful ecologically valid tests are still in then- infancy. A comparatively new test of executive functioning is the 'Hayling and Brixton Tests: Two Tests of Dysexecutive Syndi'ome', which have not been evaluated in terms of their ecological validity. Aim: The present study aimed to ascertain the ecological validity of these tests to establish their utility as clinically valid neuropsychological tools. Ecological validity was conceptualised along the lines of the WHO model of illness, where impairment is linked with disability and handicap. Method: The tests were administered to 64 brain injured participants, together with a behavioural questionnaire (assessing executive disability) and a community integration questionnaire (measuring 'handicap'). In addition, 64 people who knew the patients well were given an equivalent behavioural questionnaire plus a structured interview, rating different areas of executive functioning. Results: The Hayling and Brixton tests had modest ecological validity, comparable with previous studies. Scores on the Hayling test had the highest correlations with measures of disability, while the Brixton test performance correlated best with the measure of handicap. Regressional analyses confirmed these findings. The correlations with the handicap measure were generally lower than with the disability measures, in accordance with the WHO model of illness. Conclusion: The results suggest that the Hayling and Brixton tests are clinically useful for predicting executive disability and handicap. However, the correlations were modest, indicating that one cannot rely solely on these tests for an understanding of executive functioning and how it impacts on everyday functioning. They should also be used in combination with other neuropsychological tests and functional measures, in determining degree of impairment and associated outcome following brain injury.
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