[Prognostic value of the trigemino-facial reflex in severe post-traumatic comas]

The blink reflex (BR) study has been carried out on 40 severe head injury cases (average age 24.3 years). The recording was conducted several times between the 2nd and the 12th day and was repeated during the first month and beyond in prolonged comas. 23 patients did not respond even to high intensity stimuli. 17 patients displayed delayed and low amplitude latency responses: one of the components, early R1 or late R2 could be missing. The existence of a detectable focalized hemispheric lesion had no effect on the disappearance of the delayed lateral response. No BR was observed in mesencephalic, protubering comas and in 4 cases of subcortical and diencephalic comas. BR was observed in subcortical or diencephalic comas and in 5 cases of mesencephalic comas. The evolution of patients who did not display any electrical response during the first recording was unfavourable in 15 cases. Among the 5/8 remaining comatose cases, the BR was missing on the 2nd day and back on the 7th day. Among the 17 patients who displayed BR their evolution proved to be very favourable or favourable in 13 cases. In all the patients who survived beyond a month the response latencies proved normal, yet their amplitude was considerably lowered. The lack of BR is temporary but it is an element of unfavourable prognosis if it persists beyond a span of 8 days.