Examining sensory reweighting in healthy elderly and in those with brain injury

We investigated the manner in which complementary and conflicting visual and physical motion signals affect postural responses in healthy elderly individuals vs. an age-matched group that had experienced cortical or subcortical strokes (stroke). Subjects stood on a motion platform located within a virtual reality environment and were asked to maintain their balance in response to different combinations of platform and visual scene motions. Stroke subjects exhibited greater linearity in their kinematic responses, and appeared to place greater reliance on visual input, even when it conflicted with platform motion. We conclude this explains why stroke subjects exhibit a less stable postural response and a greater tendency to fall than healthy subjects.