Relationship between speech intelligibility, maximum comfort levels, and evoked compound action potential thresholds in patients with cochlear implants

Introduction. The study compared the values of maximum comfort levels and Electrically Evoked Compound Action Potential (ECAP) thresholds in deaf patients after cochlear implantation (CI). Patients with high speech intelligibility were selected for examination. The relationship between the values of the registration ECAP thresholds and the values of the maximum comfortable level of stimulation is revealed. Purpose of the study. Evaluation of the relationship between the values and configuration of maximum comfort levels of electrical stimulation of the auditory nerve and the ECAP thresholds in patients with high speech intelligibility after cochlear implantation. Material and methods. Thirty-nine patients with bilateral sensorineural deafness between 6 and 12 years of age were included (Me=9.4). Thirty (76.9%) patients underwent sequential CI on both sides. In 23.1% of cases (n=9) CI was performed on one side. Auditory compound action potentials (ECAPs) were recorded in all subjects, and the threshold values were compared with the Maximum Comfortable Levels (MCLs). Results. In all patients with good auditory and verbal skills development (speech intelligibility Me=91.08%), a statistically significant relationship between ECAP thresholds and MCL values was established on all channels of the electrode array. Analysis of the configuration of median MCL values (Me MCL) and electrically evoked ECAP thresholds (Me ECAP) revealed the concordance of the profile of both curves. Conclusion. The use of the most comfortable level fitting profile for CI recipients, created on the basis of registered ECAP thresholds, is a promising approach, especially at the initial stage of auditory rehabilitation. The dynamics of changes in thresholds (stimulation levels) depends on several additional factors that should be considered in the process of auditory and speech rehabilitation. © Team of authors, 2024.