Understanding and treating "pusher syndrome".

"Pusher syndrome" is a clinical disorder following left or right brain damage in which patients actively push away from the nonhemiparetic side, leading to a loss of postural balance. The mechanism underlying this disorder and its related anatomy have only recently been identified. Investigation of patients with severe pushing behavior has shown that perception of body posture in relation to gravity is altered. The patients experience their body as oriented "upright" when the body actually is tilted to the side of the brain lesion (to the ipsilesional side). In contrast, patients with pusher syndrome show no disturbed processing of visual and vestibular inputs determining visual vertical. These new insights have allowed the authors to suggest a new physical therapy approach for patients with pusher syndrome where the visual control of vertical upright orientation, which is undisturbed in these patients, is the central element of intervention.