SEMANTIC MEMORY FOLLOWING PEDIATRIC HEAD-INJURY - RELATIONSHIP TO AGE, SEVERITY OF INJURY, AND MRI

The effects of closed head injury (CHI) severity (mild vs. severe) and age at injury were analyzed in a longitudinal study (3, 12 months pos tinjury) of semantic memory which used magnetic resonance imaging (MRI ) to characterize focal brain lesions. Semantic memory was evaluated b y word and category fluency, semantic verification, semantic clusterin g in word list recall, and vocabulary. Episodic memory was assessed by word list recall. Comparison of normal control (n = 104) data with th e patients' data (n = 77) at 3 months postinjury disclosed semantic an d episodic memory deficits in the severe CHI patients. Analysis of the longitudinal data revealed significant effects of age at injury for a ll of the semantic memory measures. The effects of injury severity wer e confined to the latency of verifying correct statements. Volume of l eft frontal and extrafrontal lesions was predictive of performance on several semantic memory measures, but less robust for right hemisphere lesions.