Electrocochleography to assess sensory and neural contributions to auditory function

Electrocochleography (ECochG) is a sound-evoked potential representing cochlear and neural activity at the auditory periphery. The ECochG Total Response (ECochG-TR), a frequency-domain derived metric, has been shown to account for approximately 50% of the variance in speech perception outcomes in adult cochlear implant users. This project expands the use of ECochG-TR by investigating the feasibility of the ECochG-TR in normal-hearing participants relating it to auditory function. The central hypothesis is that there will be strong relationships between the ECochG-TR and tests of auditory function. ECochG-TR will be recorded using a bipolar montage. Hearing in spatial noise, measured as spatial release from masking (SRM), Binaural Intelligibility Level Difference (BILD), Spectral-Temporally Modulated Ripple Test (SMRT), and Interaural Time Difference (ITDs) will also be collected. Preliminary data for four normal-hearing participants revealed an average ECochG-TR of 41.16 dB μV, BILD of 7.33 dB, SRM of 33 percentage points, bilateral SMRT of 15.46 rips/oct, and ITD of 316 μs. This study establishes feasibility that the ECochG-TR can be recorded non-invasively. Preliminary findings suggest that the response is related to measures of auditory function, specifically measures of spectral resolution and temporal acuity, suggesting that the ECochG-TR might be a highly sensitive surrogate to behavioral measures.