A comparison of binaural interactions using traditional and maximum length sequence evoked response paradigms

Two paradigms, the traditional binaural interaction (BI) paradigm and a maximum length sequence (MLS) BI paradigm were evaluated to investigate BI effects.

Evoked response BI effects were assessed at different levels of the auditory pathway in two experiments. Each experiment consisted of three conditions: a traditional BI paradigm using conventional stimuli, a traditional BI paradigm using MLS stimuli, and a MLS BI paradigm using MLS techniques to recover kernels reflecting BIs. Eleven normal-hearing young adults served as subjects.

There was evidence for BI effects on the auditory evoked brain stem response (ABR) and the middle latency response (MLR) using the traditional BI paradigm and conventional stimuli. With the same paradigm and MLS stimuli there was evidence for BI effects on the MLR but not the ABR. The more robust conventional effects may be explained by the larger amplitude evoked responses recorded conventionally due to the slower stimulation rates and more efficient signal to noise enhancement. BI effects were observed for both the ABR and MLR by recording BI kernels in the MLS BI paradigm.

MLS BI kernels can be recorded in normal hearing adults. The MLS BI paradigm offers three potential advantages in recording binaural effects; avoidance of some of the methodological problems associated with traditional BI paradigms, faster stimulus rates permitting a more complete characterization of binaural rate effects, and more rapid data collection.