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Updated: Aug 20, 2026
Systematic Hearing Performance Evaluation Process for Adolescents with Cochlear Implantation at Early Ages
Published on: March 24, 2023
Toward a battery of behavioral and objective measures to achieve optimal cochlear implant stimulation levels in
Karen A Gordon1, Blake C Papsin, Robert V Harrison
1Cochlear Implant Program, Department of Otolaryngology, The Hospital for Sick Children and the University of Toronto, Room 6D08, Toronto, ON, Canada M5G 1X8.
Insights
Objective measures like electrically evoked compound action potential (ECAP) and auditory brain stem response (EABR) help determine cochlear implant (CI) stimulation levels in children. These non-behavioral tests, including the electrically evoked stapedius reflex (ESR), are feasible in the operating room and post-surgery.
Area of Science:
- Audiology
- Biomedical Engineering
- Neuroscience
Background:
- Cochlear implants (CIs) require immediate audible and comfortable stimulation post-activation.
- Objective measures are crucial for setting initial CI parameters in children.
Purpose of the Study:
- To assess the feasibility of recording ECAP, EABR, and ESR in children at implantation and over the first year.
- To evaluate changes in ECAP, EABR, and ESR thresholds and their relation to behavioral measures over time.
- To determine the predictive value of ECAP, EABR, and ESR for behavioral thresholds and loudness in pediatric CI users.
Main Methods:
- Recorded ECAP, EABR, and ESR responses in 68 children over one year.
- Utilized electrical pulses from three different electrodes along the CI array.
- Performed visual inspection of stapedius reflex (V-ESR) in an additional 20 children during surgery.
Main Results:
- ECAP and EABR were successfully recorded in over 84% of electrodes and 89% of children, both in the operating room and post-surgery.
- ESRs were recorded in over 65% of electrodes and 67% of children by 3 months, but less reliably in the operating room.
- ECAP and EABR thresholds remained stable, while ESR thresholds increased; behavioral thresholds decreased and maximum levels increased over time.
Conclusions:
- Non-behavioral measures (ECAP, EABR, ESR) aid in determining CI stimulation levels, especially in young children.
- These measures are feasible in the operating room and can be repeated post-surgery.
- ECAP and EABR thresholds can predict stimulation levels, with adjustments for electrode position and child's age, while ESR best predicts maximum levels.
Objectives:
Children require audible and comfortable stimulation from their cochlear implants immediately after device activation. To accomplish this, a battery of objective measures may be needed that could include the electrically evoked stapedius reflex (ESR), compound action potential from the auditory nerve (ECAP), and/or auditory brain stem response (EABR). In the present study, the following specific research questions were asked: In children using cochlear implants, 1) Can the ECAP, EABR, and ESR be recorded at the time of cochlear implantation? 2) What is the feasibility of measuring the ECAP, EABR, and the ESR repeatedly without the use of sedation over the first year of implant use? 3) Do ECAP, EABR, and ESR thresholds or behavioral measures change over time? 4) What is the relation between ECAP, EABR, and ESR thresholds and behavioral measures of threshold and comfortably loud levels?
Design:
In 68 children, ECAP, EABR, and ESR responses as well as behavioral measures of stimulation threshold and maximum stimulation were recorded at regular intervals over the first year of implant use. In each child, responses were recorded to electrical pulses provided by three different electrodes along the implanted array. Visual inspections of the stapedius reflex (V-ESR) evoked by activation of the same three electrodes at the time of surgery were performed in an additional 20 children.
Results:
ECAP and EABR measures were obtained in more than 84% of electrodes tested and 89% of children tested both in the operating room at the time of implant surgery (OR) and after surgery in nonsedated children. ESRs were recorded by using immittance measures in more than 65% of electrodes tested and 67% of children tested by 3 mo of implant use, but this technique was less successful in the OR and during early stages of device use. V-ESRs and ECAP thresholds were higher in the OR than ESRs and ECAPs at postoperative recording times. EABR and ECAP thresholds did not significantly change over the first 6 and 12 mo of implant use, respectively, whereas ESR thresholds increased. Behavioral measures of threshold decreased over time, whereas maximum stimulation levels rose over time. Behavioral measures of threshold and loudness were highly correlated at all test times. ECAP, EABR, and behavioral measures were lower when evoked by an electrode at the apical end of the implanted array than by more basal electrodes. Behavioral thresholds could be predicted mainly by ECAP thresholds, whereas maximum stimulation levels could best be predicted by ESR thresholds; both were significantly affected by the age at implantation.
Conclusions:
A combination of nonbehavioral measures can aid in the determination of useful cochlear implant stimulation levels, particularly in young children and infants with limited auditory experience. These measures can be made in the operating room and can be repeated after surgery when needed. Correction factors to predict threshold stimulation levels should be based on ECAP thresholds or EABR thresholds if necessary. Correction factors should be made for at least one apical and mid-array electrode, should take into account the age of the child, and may have to be revised during the first year of implant use. Maximum stimulation levels may be best determined by using the ESR.
