Introduction:  Cochlear implant (CI) has been widely used in cases with severe to profound sensorineural hearing loss. The integrity of the internal CI part after implantation could be objectively assessed by measuring the auditory response telemetry (ART) based on each individual electrode's ECAP threshold, and by postoperative imaging which provides detailed information on the position of individual electrodes specially with measurement of the electrode- modiolus distance (EMD).
Objective: We aimed to correlate between the auditory response telemetry (ART) measurements and radiological position of the electrode arrays (Electrode-Modiolus distance) inside the cochlea.
Materials and methods: Twenty-five children with severe to profound sensorineural hearing loss who had implanted unilaterally with MED-EL SONATA FLEX 28 were enrolled. Intraoperative ART results for each array were obtained. Postoperative imaging by means of a128-Multidetector CT scanner with sagittal and oblique multiplanar reconstructions (MPRs) were obtained. Images were analyzed to measure the electrode modiolus distance (EMD) and results were correlated with ART measurements.
Results: The mean ART threshold for each electrode ranged between 15.97±4.69 qu and 20.61±6.64 qu. While, the mean electrode-modiolus distance for each electrode fluctuated from 1.72±0.38 mm to 4.53± 1.27 mm. Pearson test showed a statistically significant positive correlation between the electrode- modiolus distance and the auditory response telemetry (ART) measurements.
Conclusion: Postoperative computerized tomography scanning could provide a valuable tool to assess the outcome of cochlear implant through measuring the electrode modiolus distance (EMD).