Specific time-varying digital filtering techniques for intra-operative monitoring of middle-latency and brainstem auditory evoked potential

Monitoring the whole afferent auditory pathways, in the operating room or in the intensive care unit, is possible by simultaneous recording of the brainstem (BAEPs) and the middle latency (MLAEPs) auditory evoked potentials. To reach a high level of automatization, specific methods of data processing are required, including time-varying adaptive filtering, peak detection, and trend curve generation. These methods have been implemented in a micro-computer based monitoring system and evaluated on 50 per-operative monitoring in neurosurgery.