Cerebral response to speech in vegetative and minimally conscious states after traumatic brain injury

PRIMARY OBJECTIVE: To study cerebral response in a functional magnetic resonance imaging (fMRI) task of speech perception in a sample of patients in vegetative state (VS) and minimally conscious state (MCS) after traumatic brain injury.

METHODS: Three patients in VS, four patients in MCS and 19 healthy volunteers were enrolled for the study. All subjects underwent an fMRI task of passive listening of narratives played forward and backward, alternated with periods of silence. This study analysed cerebral response to language and to complex sound processing in the healthy subjects' group and in each patient, using SPM5.

RESULTS: One patient in VS and one in MCS showed cerebral responses to language and to complex sound very similar to those shown by the healthy volunteers. Two more patients, one in VS and one in MCS, showed significant responses to complex sound only. Finally, one patient in VS and one patient in MCS failed to show significant activation in response to either stimulus.

CONCLUSIONS: Some patients in VS and MCS can preserve cerebral responses to language and auditory stimuli. fMRI may be useful to identify these responses, which may pass unnoticed in a bedside examination.