Electrodermal response and outcome from severe brain injury

The relation of electrodermal response measures to outcome from early post-traumatic vegetative state (VS) was investigated in 15 brain-injured and five control subjects. Brain-injured subjects were in acute VS or persistent VS (PVS), or had recovered from acute VS (RVS). Significant group differences were found on all electrodermal response measures, primarily due to the greater amplitude, number and consistency of responses in control subjects. Group differences in electrodermal habituation and orientation to auditory tones reflected the absence of orientation in most RVS subjects and the absence of both habituation and orientation PVS subjects. The groups differed in their response to matching faces and names. All of the control subjects, two of five RVS subjects and none of five acute subjects produced significant responses. Surprisingly, two PVS subjects also produced significant responses. For acute subjects a positive outcome at 6 months post-trauma was associated with early electrodermal startle amplitude and baseline lability. These results indicate that electrodermal responsiveness is generally reduced following acute VS, even in subjects with a relatively good recovery. Greater electrodermal activity in early VS may be associated with better potential for recovery.