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Updated: Aug 21, 2026
Electrically Evoked Stapedius Reflex Measurements in Cochlear Implantation and Its Application in the Postoperative Fitting Process
Published on: June 21, 2024
Longitudinal Analysis of Cochlear Implant Stimulation Levels in the First Year: Optimizing Adult Fitting
Maryam Hussain1, Hylke F E van der Toom1, Mats Voogelaar2,3,4
1Department of Otorhinolaryngology and Head and Neck Surgery, Erasmus University Medical Center, Rotterdam, the Netherlands.
Objectives:
The main objective of this study was to investigate the evolution in stimulation levels (C-/M- and T-levels) in adult cochlear implant users from both Advanced Bionics and Cochlear, and to assess whether this trajectory differs between the two brands. The secondary objective was to assess individual patterns of stimulation levels during the first year post-implantation.
Design:
This retrospective study was conducted at the Erasmus University Medical Center in Rotterdam, the Netherlands. A total of 183 postlingually deaf adults with a unilateral cochlear implant from either Advanced Bionics or Cochlear were included. Stimulation levels (C-, M-, and T-levels) were collected from these adults for six fitting sessions during the first year postimplantation. Linear mixed-effects models were used to analyze longitudinal changes.
Results:
Our findings were comparable for both Advanced Bionics and Cochlear implant users. Mean M/C and T levels changed over time, showing a similar characteristic pattern for each patient with a rapid increase during the initial period, followed by gradual stabilization. Post hoc comparisons revealed significant differences between appointments up to the fourth fitting session for M/C levels and up to the third fitting session for T-levels. There were no significant differences after these fitting sessions. These findings were consistent across the different electrode segments (apical, medial, upper basal, lower basal), although earlier stabilization occurred in the lower basal segment for M/C-levels and in both basal segments for T-levels.
Conclusions:
The present study gave valuable insights into the temporal evolution of M/C- and T-levels during the first year postimplantation for both Advanced Bionics and Cochlear implant users. The mean M/C- and T-levels stabilized after approximately 3 months and 5 weeks, respectively, showing equivalent trajectories between the two brands. A consistent pattern was observed across patients, with stimulation levels rising significantly in the first few months and gradually stabilizing over time.
