Modeling of the brainstem evoked response for objective automated interpretation

Audiologists use the auditory brainstem evoked response (BER) to provide an objective way of ascertaining the hearing threshold of patients. The response is recorded with an acoustic stimulus which is reduced in intensity until a response is no longer observed. Of the live predominant waves that appear within the first 10ms, wave V can be detected down to threshold level. An audiologist would look for evidence of wave V in the time domain waveform when assessing threshold level, but also take into account the morphology of the waveform. When a fast Fourier transform (FFT), is applied to the data, it shows dominant frequencies around 200, 500 and 900Hz. This can provide an alternative description of morphology. Software models are created to characterize the waveform at different stimulus intensity levels. They use information from both the time and frequency domains of the BER as input for an expert system. Results show that the use of multiple methods of modeling can aid the automated interpretation and so simulate, in some measure, the analysis work of the trained audiologist in detecting wave V.