The clinical utility of the assessment of learning potential following brain injury

Abstract

Our current evidence base for predicting outcome following an acquired brain injury (ABI) identifies factors such as the severity and impact of the injury, as well as pre-injury information as potential predictors. However current physical, medical and neuropsychological predictors are inadequate. There is a great deal of confusing and conflicting information which makes it difficult for the professionals involved in the care of those who have suffered an ABI to determine how much improvement an individual can be expected to make and what is the appropriate intensity of a rehabilitation programme. As a result patients can receive a range of treatments from different services over several years without indicators to reliably gauge outcome for all the effort both patients and staff put into this change process. The empirical research reported here suggests that limitations with current outcome predictors are that they fail to consider the individual as an active participant in their recovery process. This research explores the utility of the theory of learning potential and dynamic assessment as a tool in the field of ABI to assess the potential of an individual to adapt, and their ability to engage in the recovery process. Learning potential measures a latent or dormant ability that is brought out by a third party during dynamic training. It was predicted that dynamic testing, as opposed to simple static test administration of the same tests, could reveal important additional information to predict outcomes of ABI. In this research dynamic testing involved a pre and post test administration that sandwiched a training element. Learning potential using the Explicit Verbal Learning system was investigated with an adapted, dynamic version of the Wisconsin Card Sorting Test (WCST). Non-Verbal Learning potential was investigated with a dynamic version of the Ruff Light Trail Learning Test (RULIT) and Latent Implicit potential to learn using the Tower of Hanoi (ToH). A Rasch Analysis Model was used to examine the data in terms of the construct validity and hierarchy of the items of each test and the individuals who completed it, both pre and post-training. Individuals were grouped into different dynamic learner classifications according to their position on this scale. The results indicate a clear advantage in outcome prediction using dynamic testing. Of the three aspects considered, the measure of learning potential that added most to our understanding about the individual and outcome was the assessment utilising the Verbal Learning system (Dynamic WCST). The assessment measuring Latent Implicit learning potential (ToH) also added significantly to predicting ABI outcome. The assessment of learning potential using the Non-Verbal/Visuospatial Learning system (RULIT) however, did not add further information to help prediction of outcome. The information from the above model guided multiple regression analyses to examine the predictors of ABI outcome using each of the measures of the Community Integration Questionnaire (CIQ) as the dependent variables. Independent variables were Dynamic Verbal learner status (derived from Rasch); socio-economic status; severity of injury; predicted pre-injury intellectual functioning; education levels and current intellectual functioning. With integration status as the dependent variable (measured by the Total CIQ), Dynamic Verbal learner status and socio-economic status were the only significant predictors. Subscales tapping specific aspects of integration were not predicted by any the independent variables other than Social Integration scores, which were predicted only by pre-injury and current intellectual functioning. Collectively these results indicate that learner status may help determine the extent to which an individual can adapt following an acquired brain injury and that this latent ability significantly influences their outcome. These dynamic assessments have clinical implications in determining the level of support or treatment that an individual may require.