Paired tone-burst study of auditory brainstem response adaptation in guinea pigs: implications for development of multiple-stimulus methods.

In clinical testing using auditory evoked potentials, the practical length of a test session is limited. Thus, the amount of information that can be obtained during a routine test session is limited in electrocochleography and auditory brainstem testing. Attempts to obtain more information within a test session by increasing the stimulus repetition rate yields adapted responses. Multiple-stimulus method that present sequences of stimuli at different frequencies and intensities can increase the efficiency of data collection while avoiding adaptation. This study was designed to investigate rapid adaptation of these early responses to enable more efficient data acquisition using multiple stimuli. Five experiments in guinea pigs using single and paired tone-burst stimuli are described. The intrapair time, frequency, and intensity were varied to determine when adaptation, measured by a latency delay, occurred. The effects of adaptation on waves I through IV are described. The differences in stimulus parameters that avoid adaptation can be determined from these experiments.