Impact of divided attention during verbal learning in young adults following mild traumatic brain injury

Primary objective: The goal of the present study was to assess the impact of mild traumatic brain injury (MTBI) on episodic memory performance in relation to attentional and executive control processes in young adults. Research design/methods: A verbal memory paradigm manipulating attentional load (full attention or divided attention) and semantic congruency between pairs of category-target words during encoding was administrated to 13 individuals with MTBI and 12 normal control participants. Environmental supports during retrieval (free recall, cued recall and recognition modes) were also manipulated. Main outcomes and results: Results show that recall performances of individuals with MTBI were similar to those of controls when words were encoded under full attention. In contrast, individuals with MTBI performed worse than control participants when encoding under divided attention, whatever the semantic link between pairs of words. Conclusions: By using a sensitive test, one was able to objectively measure subtle impairments in memory performance, suggesting a diminished availability of attentional resources after MTBI. Young adults' learning of verbal material under divided attention might be compromised by the reduction of cognitive resources following MTBI. These findings are also discussed in light of different factors that can influence cognitive performance.