Nicolas Schweighofer: “Virtuous and vicious cycle between arm use and performance post-stroke”
CiNet 1F Conference Room
University of Southern California
Host : Daniel Callan (PI)
Although spontaneous use of the more-affected upper extremity after stroke is an important determinant of participation and quality of life, a number of patients exhibit decreases in use following rehabilitative therapy. Our general hypothesis that there exists a threshold for function of the paretic arm and hand after therapy. If function is above this threshold, spontaneous use will increase in the months following therapy. In contrast, if function is below this threshold, spontaneous use will decrease. A previous “qualitative” neuro-computational model predicted that if the dose of therapy is sufficient to bring performance above a certain threshold, training can be stopped. Computer simulations are presented showing how changes in arm use following therapy depend on a performance threshold. This prediction was tested by reanalyzing the data from the extremity constraint-induced therapy evaluation (EXCITE) trial, phase III randomized controlled trial in which participants received constraint-induced movement therapy for 2 weeks and were tested both 1 week and 1 year after therapy. Next, we present a “quantitative” model, with parameters fitted to longitudinal data of individual patients recovering from stroke, that allow us to estimate the effect of therapy on the time-varying interactions between arm function and use. Finally, we will present recent data from both non-disabled and post-stroke individuals that suggest that expected movement duration, expected effort, and expected task success all influence arm choice.