Hand movement span after mild traumatic brain injury: a longitudinal study.

This study examined whether memory span was impaired during the acute and post-acute phases following mild traumatic brain injury (mTBI). Twenty-two adults with mTBI were compared with 22 controls on computerized tasks of immediate memory for verbal, spatial, and hand movement sequences under no interference (baseline) and articulatory suppression conditions. Groups were assessed within a month and followed up 3-12 months post-injury. In the acute phase, there were no group differences across tasks under either condition. At follow-up, all spatial and verbal span scores and associated practice effects were equivalent across groups. Yet for the hand movement task, baseline movement span was worse for the mTBI group suggesting that they failed to benefit from practice to the same extent as controls. Furthermore, the fact that this group difference in span scores disappeared when articulatory suppression was imposed indicates that successful hand movement task performance involves verbal recoding.