A Clinically Viable Method of Recording the Electrically-Evoked Acoustic Change Complex in Adult Cochlear Implant Users - OMAI 2018- The 10th International Symposium on Objective Measures in Auditory Implants

Wayne Ellis ¹ Rajeev Mathew ² Jaime Underraga ³ Axelle Calcus ⁴ Patrick Boyle ⁵ Wayne Ellis ⁴

¹Auditory Implants, University College London Hospitals NHS Foundation Trust, London, UK
²ENT Department, St George's Hospital NHS Trust, London, UK
³Department of Linguistics, Macquarie University, Sydney, UK
⁴Department of Speech, Hearing and Phonetic Sciences, University College London, London, UK
⁵European Research Center, Advanced Bionics GmbH, Hannover, Germany

Background:

It has recently been shown that the electrically-evoked acoustic change complex (eACC) can be used to objectively assess electrode discrimination ability in all three major CI manufacturer’s devices (Mathew et al., 2017). Most studies, however, have used multi-channel EEG recording systems, which are rarely accessible in most CI clinics, and direct stimulation paradigms. The setup and recording time for such systems also makes them unfeasible for clinical use. Techniques for improving the efficiency and sensitivity of eACC recordings are therefore required.

Objective:

To assess the validity of recording the eACC using single channel scalp recordings and acoustic stimuli in all three major CI manufacturer’s devices.

Methods:

Nine subjects underwent testing. Stimulation level was at the most comfortable level and electrode pairs were loudness balanced. Stimuli for the eACC recording were 1000ms pure tones at the centre frequency of adjacent electrode pairs.

Results:

It was possible to record the eACC in all subjects. Averaging testing time for 8 electrode pairs was around 30 minutes.

Conclusion:

The eACC can be reliably recorded in all three major CI manufacturer’s devices using acoustic stimuli and a single channel scalp recording system.