Slowness of information processing after traumatic head injury.

One of the main aftereffects of traumatic head injury is slowness of information processing. In the present study, it was hypothesized that an important causal mechanism is a problem in the activation of information stored in memory; this is thought to be due to a reduced redundancy of these representations. An experimental drawing task was employed in which the degree of familiarity and motor complexity of the items was varied. It was expected that increasing the novelty of a task would be more detrimental for the patients than increasing motor complexity. Ten head-injured patients and 10 matched control subjects participated. Task execution was recorded on-line on a graphic digitizer. The results were in accordance with the hypothesis: That is, novelty but not motor complexity had a crucial influence on the speed of information processing. The implications of the results for therapy are discussed.