Long-Term Results of Cochlear Implantation in Single-Sided Deaf Patients: Influence of Duration of Deafness and Age at Onset of Deafness.

Objective: The aim of the current study was to investigate the influence of duration, time point, and etiology of deafness on cochlear implant user rates, and to investigate the long-term hearing performance in single-sided deaf patients.

Study design: Retrospective study.

Setting: Tertiary care hospital.

Patients: 77 subjects with single-sided deafness.

Intervention: Unilateral cochlear implantation between 2009 and 2022.

Main outcome measures: Patients were categorized into users and nonusers. Duration of deafness, onset of deafness, etiology, and further demographic data were collected. Pure tone audiometry, Freiburg numbers, and monosyllables test were carried out at activation, as well as 1 year, 2 to 3 years, and 5 years after cochlear implant activation.

Results: Most patients who lost their hearing after the age of 10 years were cochlear implant users, while patients who lost their hearing earlier and were implanted with a significant delay were likely nonusers. Even patients implanted more than 10 years after the hearing loss regularly used the cochlear implant, if deafness occurred at the age of 10 years or later. Implanted patients showed an improvement of hearing from activation to 1 year postoperatively as well as stable hearing thresholds for 5 years.

Conclusions: The timing of hearing loss influences cochlear implant user rates. Patients who acquired single-sided deafness above the age of 10 years use the device regularly even if the duration of deafness was more than 10 years. This challenges the 10-year cutoff for cochlear implant indication. Furthermore, results show good long-term hearing thresholds and speech understanding for cochlear implant patients who use their device regularly.