Is there a trade-off between cognitive and motor recovery after traumatic brain injury due to competition for limited neural resources?

The status of neurorehabilitation for traumatic brain injury (TBI) is under active debate because of a dearth of research findings demonstrating effectiveness. This may be due, in part, to limitations in our understanding of basic mechanisms of cognitive and motor recovery,including those that might impede recovery. In this regard, we examined whether overall recovery following TBI might be undermined by competition between cognitive and motor functions for finite neural resources during recovery. In this preliminary study, 21 moderately and severely impaired patients were administered cognitive and motor assessments at 1, 4, and 12 months post-TBI, and recovery of cognitive and motor functions was measured using regression residuals. Negative correlations between recovery of cognitive versus motor functions were used as the index of competition. We found suggestive evidence that there may indeed be a trade-off between the recovery of cognitive and motor functions after TBI. Implications for rehabilitation are discussed.

Evidence of transient enhancement to cognitive functioning in healthy young adults through environmental enrichment: implications for rehabilitation after brain injury.

We examined preliminarily whether intensive mental activity can transiently enhance higher cognitive functioning in healthy adults. Ten healthy participants performed intensive mental activity for 2 weeks. The intervention entailed daily memorization of multiple prose passages and performance of demanding, speeded mental arithmetic.Neuropsychological testing was conducted before and after the intervention, using alternate forms. (The intervention and neuropsychological tests were different.) Findings in the intervention group were compared to those of a convenience control sample who had performed a near-identical neuropsychological assessment and follow-up in a different study, but who did not perform the intervention. The purpose was to rule out practice effects as the cause of any observed improvement in the intervention group. The intervention group showed improvement on six/eight measures. The non-intervention group showed improvement on only two. Results suggest cognitive capacity can be enhanced in healthy individuals after a period of intensive cognitive stimulation. Implications for rehabilitation are discussed.