Word fluency in relation to severity of closed head injury, associated frontal brain lesions, and age at injury in children

Effects of closed head injury (CHI) severity, focal brain lesions, and age at injury on word fluency (WF) were studied longitudinally in 122 children (78 severe, 44 mild); 112 CHI patients (68 severe, 44 mild CHI) and 104 uninjured normal controls participated in a cross-sectional study. WF was measured by asking the child to generate as many words as possible beginning with a designated letter within 60 s, repeated for three letters. Intellectual ability, receptive vocabulary, narrative discourse, and word list recall were also measured. Results of the cross-sectional study showed a significant group effect with poorer WF in severe CHI than mild CHI and control groups. Growth curve analysis of longitudinal data revealed an interaction of age, follow-up interval, and CHI severity as WF recovery was slower after severe CHI in younger children as compared to severe CHI in older children or mild CHI in younger children. An interaction of left frontal lesion with age and interval indicated a more adverse effect on WF in older children. Right frontal lesion effect was nonsignificant and did not interact with age. Correlations of WF with receptive vocabulary, word list recall, and narrative discourse were moderate and weak with estimated intellectual ability. Differences in focal lesion effects after traumatic versus nontraumatic brain injury in children, the contribution of diffuse white matter injury, reduced opportunity for language development, and functional commitment of left frontal region at time of CHI were discussed.