Cochlear Implant-based Cortical Activity Recordings
A research page describing the experimental framework, clinical translation, and signal-processing approach behind this cochlear implant work.
Project Overview
This work investigates how intracochlear stimulation can be used to recover informative cortical responses in patients with cochlear implants. The project draws on clinical collaboration, electrical measurement, and computational modelling to build a more robust understanding of how auditory-evoked activity can be detected and interpreted.
The programme has also received funding from the RNID, supporting the development of methods that could improve how auditory responses are measured and understood in clinical practice.
Methodology
A central element of the workflow is automated electrical impedance spectroscopy, which characterises the implant system under controlled stimulation conditions and supports repeatable measurements across sessions.
The impedance spectra are fitted to a Cole-Cole model to extract parameters that describe the electrical behaviour of the implant-tissue system in a compact and interpretable form. Complementary COMSOL models were also used to assess how implant geometry and the surrounding medium influence field distribution and signal behaviour.
Clinical Trials
The clinical component involved a 16-patient study designed to assess the feasibility and reliability of the approach in a real-world cochlear implant population. The study used ipsilateral stimulation to reduce ambiguity in the interpretation of observed responses and compared the resulting measurements with scalp-EEG recordings.
This comparison was essential for determining whether the implant-based recordings captured meaningful cortical activity beyond what could be inferred from standard surface measurements.
Results
The results show that the noise-removal approach substantially improved recording clarity, increasing signal-to-noise ratios by up to 13 dB. This improvement was especially valuable in a setting where small neural signals are easily obscured by instrumentation noise and physiological variability.
Taken together, the findings support the technical feasibility and clinical promise of the method for future auditory neurophysiology work.