Linear and nonlinear temporal interaction components of mid-latency auditory evoked potentials obtained with maximum length sequence stimulation.

A maximum length sequence (MLS) is a quasi-random sequence of clicks and silences that enables simultaneous recording of linear components and nonlinear temporal interaction components (NLTICs). NLTICs are produced when the stimulation rate is fast enough such that several stimuli occur within the memory length of the system. The present study was designed to characterise the NLTICs of auditory mid-latency responses (MLR). Forty normally hearing subjects (19-45-year-old) were tested at MLS rates between 20 and 120 clicks/s. Linear components could be identified at all rates. The NLTICs of the MLS-MLR were identified in only a few subjects. This suggests two possibilities: (1) there may not be strong nonlinear temporal interactions within the MLR generators; (2) the memory length of the MLR is much shorter than expected from the linear component rates. If so, NLTICs should be obtained at higher rates of stimulation.