The learner driver with spina bifida and hydrocephalus : can driving ability be predicted?
The focus of this thesis is on the possible effects of cognitive deficit on the acquisition of driving skills in young people with spina bifida and hydrocephalus (SBH). The specific question addressed is whether success on the standard Driving Test can be predicted from performance on a battery of psychometric tests. A review of the findings from studies on cognitive deficit and driving and the cognitive functioning of groups with SBH identified the areas of visual-perceptual skill, attention and memory as being of possible relevance in the assessment of suitability for driving. The second part of the thesis describes the development of a battery of tests to assess not only these skills, but also visual-motor ability, which, from results during the early stages was also thought to be of value in the assessment of skills for driving. During development of the battery, the perceptual-cognitive tests chosen were completed by two series of SBH adults and by four matched groups of varying ability (able-bodied, SBH, SB only and cerebral palsy). As the work progressed, it became clear that the prediction of driving success from cognitive tests was limited. However, the results of these studies and a small-scale study of 14 learner drivers during early tuition, highlighted efficient visual disembedding and memory skills as important for learning to drive. Of additional importance was the consistent finding that the reasons why a person did not become a driver had many causes, not necessarily related to cognitive functioning. In particular, financial circumstances, the availability of adapted cars and driving instructor techniques were often overiding factors in determining whether a person reached Driving Test standard or not. No definitive answer, therefore, can be given to the specific question addressed in this thesis - can driving ability be predicted? It is clearly indicated, however, that although sound perceptual-cognitive skills are a prerequisite for learning to drive, they are not alone sufficient to predict driving success.