Long-term outcomes of cochlear implantation in Usher syndrome

New insights from research

Recent research by Mirthe Fehrmann and colleagues at Radboudumc has provided significant new insights into the long-term outcomes of cochlear implantation (CI) in people with Usher syndrome. The study focused on the effectiveness of cochlear implants in different subtypes of the syndrome (USH1, USH2, and USH3), with a special emphasis on long-term outcomes. The findings have been published in the renowned journal Ear & Hearing.

Usher syndrome is a hereditary disorder characterized by a combination of hearing loss or deafness and progressive vision loss due to retinitis pigmentosa (RP). As a result, people with Usher syndrome rely heavily on their hearing for communication and orientation. Cochlear implants (CI) offer a solution for many, but until now, there has been a lack of extensive studies examining the long-term effectiveness of CI in the various subtypes of Usher syndrome.

Study design
The study examined 36 patients with Usher syndrome who received cochlear implants at Radboudumc (53 ears). The patients were divided into four groups: early-implanted USH1, late-implanted USH1, USH2, and USH3. Speech recognition with CI was measured at various time points after implantation: at 1 year, 2 years, and 5 years or more.

The study aimed to evaluate the performance of cochlear implants in people with different subtypes of Usher syndrome in both the short and long term. The focus was on improvements in speech recognition and overall satisfaction with the implantation.

Key findings

• USH1 (early implantation, younger than 7 years): Early-implanted patients (median implantation age = 13 months) achieved excellent results, with 100% speech recognition after an average of 12 years. Early, simultaneous bilateral implantation led to much better speech recognition than sequential implantation.
• USH1 (late implantation, older than 7 years): In late-implanted patients, CI was primarily used for sound detection, with an average speech recognition of only 12%. However, these patients were satisfied with their ability to perceive environmental sounds and used the implant more as a signaling device.
• USH2: Patients with USH2 who received a CI generally achieved good results, with an average speech recognition of 85% after 8 years of follow-up. Early implantation and better speech perception with hearing aids before implantation led to better results. Delaying the decision to receive a CI if eligible is therefore not advisable.
• USH3: Results in USH3 patients were more variable, with an average speech recognition of 71%. The small number of patients in this group and the fact that some had been severely hearing impaired for a long time before receiving a CI explain the variation.

* For more information on the different subtypes of Usher syndrome, read here.

This study demonstrates that cochlear implants are effective in improving hearing in people with Usher syndrome, both in the short and long term. For patients with USH1, early bilateral implantation is strongly recommended for the best results. Late implantation, while providing a signaling function, is not sufficient for effective oral communication.

In USH2 and USH3, early implantation is crucial to slow the progression of hearing loss, especially given the severe visual impairments. For USH2 patients with sufficient speech recognition before implantation, the results are particularly favorable. In USH3, the variability of symptoms creates more uncertainty regarding outcomes, requiring careful counseling. However, it is expected that when implanted early enough, USH3 patients can achieve results comparable to those in USH2.

Practical implications

• Early implantation is crucial to achieve optimal results.
• Simultaneous bilateral implantation, ideally between 6 and 12 months of age, is recommended for USH1 patients to maximize speech recognition and hearing performance.
• USH2 and USH3, good results are achievable, especially when patients have received sufficient auditory stimulation and used hearing aids before implantation. When speech recognition with hearing aids falls below 70% (at 65 dB speech), CI can already be considered.
• Counseling and education should emphasize the importance of early detection and timely implantation, as well as encouraging the use of hearing aids to keep auditory pathways active.

These findings support a proactive approach to the treatment of Usher syndrome:

• Screening and early diagnosis are essential to intervene in a timely manner and improve the quality of life for patients.
• Multidisciplinary collaboration between audiologists, ophthalmologists, geneticists, and rehabilitation specialists can contribute to an integrated care approach.
• Individual treatment plans should be developed, considering the specific subtype, symptom progression, and the patient’s personal needs.

With timely and appropriate treatment, patients can experience significant improvements in their hearing, leading to better communication and an enhanced quality of life despite the challenges of the syndrome.

Source: Fehrmann, M.L.A., Lanting, C.P., Haer-Wigman, L., et al. (2024). Long-term outcomes of cochlear implantation in Usher syndrome. Journal Name, Volume (Issue), Pages. DOI: 10.1097/AUD.00000000000001544