Short and long term preservation of hearing thresholds corrected for natural hearing loss in cochlear implant recipients using a straight electrode

Abstract

Objectives: The aim of this study is to investigate short and long term residual hearing preservation (HP), corrected for the natural progress of hearing loss, in cochlear implant (CI) patients receiving a straight electrode array using a round window (RW) approach.

Methods: A retrospective and cross-sectional analysis on patients who received a CI with a straight electrode using a RW approach (n = 60) was performed. Audiometric data were obtained at three time points, preoperatively, at first fitting, and one year or more postoperatively. The HP outcome was calculated according to the HP definition as reported by Skarzynski with a PTA of 250, 500, and 1000 Hz (PTA3) and a PTA of 250, 500, 1000, and 2000 Hz (PTA4).

Results: The HP outcome at first fitting and at long term follow up fell into the partial HP category, 63.5% (PTA3) and 40.5% (PTA4), respectively according to the Skarzynski definition. A decline in pure-tone average (PTA) was found in the CI ear and in the contralateral ear over time (p < 0.05). Interaural differences remained relatively stable at all frequencies on the long term, except for the frequency 250 Hz (p < 0.05).

Discussion: After the initial loss of residual hearing, the hearing thresholds of the CI ear remain relatively stable at long term follow up when corrected for the natural course of hearing loss, except at 250 Hz.

Conclusion: CI candidates should be counseled on the risk of long term deterioration of the residual hearing in both the CI ear and the contralateral ear.

Keywords:

• Cochlear implantation
• Hearing preservation
• Residual hearing
• Sensorineural hearing loss
• Clinical practice guidelines

Notes on contributors

Drs. Snels (MD, MSc) has studied Medicine and clinical research at Maastricht University (The Netherlands). She has started a PhD position in 2016 at the department of Otorhinolaryngology at the University Hospital Ghent (Belgium). The topic of her PhD is ‘Hearing preservation in cochlear implantation’. She has published in international journals and has contributed to several national and international conferences.

Dr. Huinck is clinical scientist at the Radboud university medical center in Nijmegen. She studied at the Radboud University speech and language science and works since 2000 at the Radboudumc. In 2006 she finished her PhD. She is specialized in and responsible for the CI indication in adults and works as a researcher and PhD supervisor. Dr. Huinck published numerous articles in national and international journals and contributed to many national and international conferences.

Dr. Swinnen is an audiologist at the Ghent University Hospital (Belgium) where she’s concerned with preoperative selection testing of CI candidates and postoperative fitting and audiological rehabilitation. Besides being an audiologist, she is also a teacher in the Audiology Master education at the Ghent University. Dr. Swinnen has been a contributor of numerous publications in national and international journals and contributed to many national and international conferences. She is also a supervisor of Master theses and PhD students.

Ingeborg Dhooge, born in Eindhoven, Nederland on 28 december 1963, graduated in 1988 as a medical doctor at the Ghent University. She received her PhD degree in medicine at University Groningen in The Netherlands. She completed her ENT residency at the University Hospital Gent where she is currently full professor in otology at the Faculty of Medicine and head of the ENT Department since 2007. She manages the Ghent cochlear implant center and the tinnitus clinic. Her research group has built up expertise in the field of hearing loss, with focus on (re)habilitation and genetics of deafness. Tinnitus has also been a focus of clinical care and research since many years. She published more than 140 A1 articles, she wrote 10 chapters in books and edited one book on ENT pathology. She is a member of various scientific committees. She is board member of the Flemish-Dutch pediatric working group on Otorhinolaryngology and board member of the ESPO (European Society of pediatric Otorhinolaryngology).

Professor Dr. Mylanus is an ENT surgeon at the Radboud University Medical Center Nijmegen (The Netherlands). He is an associate professor of the research group Cochlear Implantation of the Donders Institute for Brain, Cognition and Behaviour (Nijmegen, The Netherlands). He is a member of multiple workgroups and scientific societies and has been a contributor of a couple of books and published numerous articles in national and international journals. Professor Dr. Mylanus is also a supervisor of PhD students.

ORCID

Chantal W. M. Snels http://orcid.org/0000-0001-8640-5479

Wendy J. Huinck http://orcid.org/0000-0003-3479-4657