ACCESS AND ORGANIZATION OF GOAL-DERIVED CATEGORIES AFTER TRAUMATIC BRAIN INJURY

This study examined the access and organization of goal-derived catego ries in semantic memory with a group of chronic traumatic brain injure d TBI adults and a group of age and gender-matched neurologically-inta ct controls. Goal-derived categories are developed by individuals for use in specialized contexts to achieve a goal, such as 'things to take on a camping trip.' Categories were presented to subjects in two task contexts: category verification and exemplar generation. Overall, the TBI subjects were able to accurately identify and organize category e xemplars within particular categories. Interestingly, the TBI subjects produced significantly more total responses than the neurologically-i ntact subjects on exemplar generation; however, a high percentage of t heir responses (one-third) were inaccurate, consisting of out-of-set r esponses and repetitions. These findings suggest that difficulties in retrieval may exist in the presence of relatively intact access and or ganization of goal-derived category structure. The results are discuss ed relative to deficits in the executive control of verifying goal-dir ected behaviour and incomplete category representation.