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Author Spotlight: Advancements in Impedance Monitoring for Cochlear Implant Surgery
Published on: August 4, 2023
Risk factors for loss of ipsilateral residual hearing after hybrid cochlear implantation
Jonathan C Kopelovich1, Lina A J Reiss, Jacob J Oleson
1*Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa; †Department of Otolaryngology Head and Neck Surgery, Oregon Health Science University, Portland, Oregon; and ‡Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, Iowa, U.S.A.
Objective:
Residual low-frequency acoustic hearing benefits cochlear implantees in difficult listening situations such as understanding speech in noise and music appreciation. Most subjects retain functional residual hearing in the operated ear. A small number of patients, however, will lose significant ipsilateral residual hearing after short-electrode cochlear implantation. The objectives of this retrospective series are to determine whether predisposition to hearing loss after implantation exists in a subset of patients and to assess the functional impact of this hearing loss on clinical measures of combined electric and acoustic hearing.
Study Design:
Retrospective case series.
Setting:
Multicenter clinical trial; tertiary care facility.
Patients:
Hearing preservation cochlear implant recipients.
Main Outcome Measure:
Frequency-averaged ipsilateral hearing loss at 1 year after activation.
Results:
Eighty-five patients from the Hybrid S8 FDA trial had serial postoperative audiometric measurements. Twenty-two of these patients, implanted at the home institution, provided additional medical data. Univariate analysis (Pearson's, Spearman's, Student's t test) showed that the severity of hearing loss at 1 year after activation was significantly correlated with age, male gender, and noise-induced hearing loss as the etiology of hearing impairment. A multivariate regression model corroborated these variables. No other medical factors were predictive. Clinical measures of speech perception (Consonant-Nucleus-Consonant and Hearing in Noise Test) worsened with hearing loss in ipsilateral but not bilateral listening conditions.
Conclusion:
Age, male gender, and a history of noise-induced hearing loss correlate with the severity of hearing loss at 1 year after activation. Even the most severely affected patients benefit from bilateral electric and acoustic inputs.
