In 70 comatose patients, the auditory brain stem response (ABR) was recorded on a time-course basis to judge prognosis. The time taken to judge prognosis and which of the two recorded responses, namely one on the right and the other on the left, reflects prognosis were also studied. As a result, the latency of the III-V wave was prolonged with the lapse of time in the vegetable cases compared with the recovery cases. In the case of death, the I-III wave latency in addition to III-V wave latency was prolonged with time. This suggested that judging prognosis by only one measurement would be risky and that making observations of ABR on a time-course basis would be necessary in judging prognosis. Changes in the I-V wave latency on the right were not necessarily consistent with those on the left in the same case. However, there was no difference in changes between the right and left as observed by prognosis. Therefore, either right or left responses may be used in judging prognosis.
