Heart rate and skin conductance reactivity to brief psychological stress in brain-injured patients

Autonomic reactivity in response to two mentally challenging tasks was studied in 74 patients with traumatic brain injury (TBI; n=33), cerebrovascular insults (CVA; n=27), and hypoxic brain damage (n=14). Heart rate, skin conductance level, and number of spontaneous skin conductance responses were recorded during baseline and two problem-solving stress conditions consisting of Raven progressive matrices and mental arithmetic. CVA and TBI patients with focal right hemisphere injury showed significantly reduced stress reactivity compared to patients with focal left hemisphere injury. This right-left hemisphere difference was maintained when controlled for diagnosis, gender, sex, age, and stressor task performance and involvement. The results indicate that lateralization of lesion rather than diagnosis or etiology is the critical factor in autonomic stress hyporeactivity in brain-injured patients. The results are discussed in relation to brain lateralization of autonomic reactivity and possible clinical consequences of autonomic hyporeactivity for rehabilitation of patients with acquired brain injury. (C) 1998 Elsevier Science Inc.