PRIMARY OBJECTIVE: This study used an object definitions test to examine semantic memory and the organization of semantic knowledge during the early stage of recovery from traumatic brain injury (TBI). RESEARCH DESIGN: Twenty-four participants with moderate-to-severe TBI and 24 controls described three living and three non-living objects as if they were describing them to someone who had never heard of or seen such things before. METHODS AND PROCEDURES: The verbal definitions were examined at a feature level and for whether they communicated the core concept (i.e. could a blind rater identify the object). MAIN OUTCOMES AND RESULTS: Compared to the control group, the TBI group less often provided object definitions that communicated the core concept and included superordinate category information. The TBI group also produced a smaller proportion of physical specific features and the production of fewer physical specific features was associated with lower production of the core concept. Despite these group differences, both groups produced more specific feature information about the objects than general feature information; and more physical specific features for living objects and associative specific features for non-living objects. CONCLUSIONS: The findings were interpreted as suggesting a decreased efficiency in ability to access semantic information following moderate-to-severe TBI, which influenced core concept production, despite intact organization of semantic knowledge.
PRIMARY OBJECTIVE: This study used an object definitions test to examine semantic memory and the organization of semantic knowledge during the early stage of recovery from traumatic brain injury (TBI). RESEARCH DESIGN: Twenty-four participants with moderate-to-severe TBI and 24 controls described three living and three non-living objects as if they were describing them to someone who had never heard of or seen such things before. METHODS AND PROCEDURES: The verbal definitions were examined at a feature level and for whether they communicated the core concept (i.e. could a blind rater identify the object). MAIN OUTCOMES AND RESULTS: Compared to the control group, the TBI group less often provided object definitions that communicated the core concept and included superordinate category information. The TBI group also produced a smaller proportion of physical specific features and the production of fewer physical specific features was associated with lower production of the core concept. Despite these group differences, both groups produced more specific feature information about the objects than general feature information; and more physical specific features for living objects and associative specific features for non-living objects. CONCLUSIONS: The findings were interpreted as suggesting a decreased efficiency in ability to access semantic information following moderate-to-severe TBI, which influenced core concept production, despite intact organization of semantic knowledge.