Eclipse eABR for Cochlear Implant (CI) Fitting: A Case Story
“Eclipse eABR is a valuable tool in the evaluation of the threshold and functional status of the auditory system,” says Prof. Martin Walger, from the Cochlear Implant Center of the ENT University Clinic in Cologne, Germany.
In the audiological center of the ENT University Clinic in Cologne, Prof. Martin Walger, and his team of audiologists and ENT specialists, have treated thousands of patients of all ages with suspected hearing impairment. Each year, around 100 patients are fitted with a cochlear implant by the multidisciplinary team at the Cochlear Implant Center in Cologne.
eABR for CI fitting and auditory assessment
One of the tools used to evaluate the fitting of the CI and the function of the auditory system is the electrical auditory brainstem response (eABR). For this, Prof. Walger and his team use the Interacoustics Eclipse – both during and after CI surgery:
“We use the evoked potential software of the CI supplier, which delivers the electric stimuli for any selected CI electrode and the trigger for the Eclipse system. We record the eABR from the contralateral side using an electrode montage (FP/contralateral mastoid) for the ipsilateral channel,” he says.
Clearly visible waves eIII and eV
According to Prof. Walger, one of the benefits of the Eclipse system is clearly visible waves eIII and eV of the eABR in CI recipients with normal speech recognition scores:
“Selecting any CI electrode, we can follow wave eV down to the subjective threshold in relaxed patients or during sleep. Therefore, the threshold as well as the functional status of the auditory system can be evaluated,” he says.
Interacoustics recently improved their Eclipse amplifier and their software has been updated with new features and better performance. According to Prof. Walger, this has made a huge difference as the Eclipse system is now able to deal with large electrical artifacts and still obtain reliable results:
“Within the first few milliseconds, the amplifier and hardware filter setting as well as the new feature for hiding artifacts enable clear visible responses and easier handling of the different waveforms,” he says.
The true importance of eABR
The recording of eABR is an important tool for the evaluation of both the function of the CI and the auditory pathway in CI recipients. “Immediately during surgery and after the CI electrode insertion into the cochlea, we receive objective information about the synchronous activation of the auditory nerve and central auditory processing on brainstem level after electrical stimulation,” Prof. Walger explains.
The ENT University Clinic in Cologne performs eABR recordings in challenging CI cases where patients are unable to give reliable responses during CI fitting or during behavioral auditory testing of especially younger children.
“Sometimes, side effects like facial nerve stimulation or hints of central auditory processing disorders, for example after bacterial meningitis, or an unexpected poor performance during our rehabilitation program, provide good arguments to carry out eABR recordings. Especially in CI recipients with auditory synaptopathy/auditory neuropathy (AS/AN), the synchronous activity of the CIs as well as the maturational progress during CI rehabilitation can be evaluated and the obtained results have an impact on our hearing and speech therapists,” Prof. Walger explains.
During the past decades, the CI indication criteria have expanded, and therefore, according to Prof. Walger, it is also important to perform eABR measurements in CI recipients with inner ear malformations, hypoplasia of the auditory nerve, temporal bone injuries or after acoustic neuroma surgery:
“In these cases, it is very important to evaluate the functional status of the auditory nerve and central auditory system, the maturational progress and neuronal plasticity after cochlear implantation.”
Making a difference for patients
At the Cochlear Implant Center of the ENT University Clinic in Cologne, they do not only use the Eclipse for CI patients. They also use it for objective differential diagnosis of hearing loss in children and adults at any age.
“The Eclipse is an essential tool in our clinic. We perform the registration of otoacoustic emissions [TEOAE and DPOAE], click-and narrowband CE-Chirp® evoked ABR and ASSR in ambulant settings or in the operation room using insert earphones. In cases of mixed- or sound-conductive hearing loss, we use B81, the new bone conductor, as it goes up to the stimulation level of 70 dB HL,” Prof. Walger says.
Objective evaluation of CI function
In addition to the results of subjective audiometry and medical and educational examinations, the eABR technique also provides valuable objective data on the current status and course of CI care:
“Particularly in the case of small children, uncooperative patients or in difficult developmental processes, it is particularly important to carry out an objective evaluation of CI function by recording the eABR. That way, we can evaluate the fitting of the CI on each individual electrode and we can objectify implant malfunctions, side effects such as facial nerve irritation, as well as maturation and auditory processing disorders,” Prof. Walger says.
“Subsequently, we can adjust and modify the fitting of the implants and the rehabilitation. Therefore, the eABR results increase the quality of our CI program, increase the performance of our patients, reduce the number of non-users and uncover side effects.”
Want to learn more about Eclipse eABR?
Head to our Eclipse page to learn more.
On September 24, 2020, 16.00-17.00 CEST, Dr. Martin Walger, Ph.D., presented the following webinar: ‘eABR in Cochlear Implantation – using the CI as an electrical stimulator’. Find a recording of the webinar here.
Alternatively, please refer to the webinar below: ‘An introduction to eABR’. Presented by Amanda Goodhew, MSc Audiology.
Finally, if you are ready to get stuck into eABR testing, click here for a complete guide on how to perform eABR testing with the Eclipse.
About the authors
Charlotte Ellemose Sonne is a Master of Linguistics and Communication (cand.ling.merc.), having graduated from Aarhus University in 2004. Before joining Interacoustics, Charlotte's working experience included, among other, a seven year stay at DONG Energy (now Ørsted) as a Language Specialist.
Dr. Martin Walger, Ph.D., is a Professor of Audiology and Head of the Department of Audiology and Pediatric Audiology at the ENT University Clinic as well as the audiological head of the Cochlear Implant Center (CIK) of Cologne, Germany. Educated in the fields of biology and audiology, he earned his Ph.D. investigating effects of noise on the central auditory pathway. His scientific research concentrated on the maturation and plasticity of the auditory system under the influence of hearing loss. He is past-president of the German Society of Audiology (DGA) and Council member of the International Evoked Response Audiometry Study Group (IERASG).