Outcomes of cochlear implantation in Usher syndrome: a systematic review

Abstract

Purpose: This study is a systematic review of the literature which seeks to evaluate auditory and quality of life (QOL) outcomes of cochlear implantation in patients with Usher syndrome.

Methods: Systematic review of studies indexed in Medline via PubMed, Ovid EMBASE, Web of Science, CENTRAL and clinicaltrials.gov was performed up to March 9th 2022, conducted in accordance with the PRISMA statement. Patient demographics, comorbidity, details of cochlear implantation, auditory, and QOL outcomes were extracted and summarized.

Results: 33 studies reported over 217 cochlear implants in 187 patients with Usher syndrome, comprising subtypes 1 (56 patients), 2 (9 patients), 3 (23 patients), and not specified (99 patients). Auditory outcomes included improved sound detection, speech perception, and speech intelligibility. QOL outcomes were reported for 75 patients, with benefit reported in the majority.

Conclusions: Many patients with Usher syndrome develop improved auditory outcomes after cochlear implantation with early implantation being an important factor.

Keywords: Cochlear implant; Hearing loss; Quality of life; Usher syndrome.

Fig. 1

Preferred reporting items for systematic reviews and meta-analyses flow diagram. From: Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71. https://doi.org/10.1136/bmj.n71. For more information, visit: http://www.prisma-statement.org/

Fig. 2

Risk of bias assessment using Brazzelli tool [7] and OCEBM grading [6]. Key: Y = yes, N = no, U = unclear. 1. Were participants a representative sample selected from a relevant patient population (e.g. randomly selected from those seeking treatment despite age, duration of disease, primary or secondary disease and severity of disease)? 2. Were the inclusion/exclusion criteria of participants clearly described? 3. Were participants entering the study at a similar point in their disease progression (i.e. severity of disease)? 4. Was selection of patients consecutive? 5. Was data collection undertaken prospectively? 6. Were the groups comparable on demographic characteristics and clinical features? 7. Was the intervention (and comparison) clearly defined? 8. Was the intervention undertaken by someone experienced at performing the procedure? (‘Yes’ if the practitioner received training on conducting the procedure before or conducted same kind of procedure before (i.e. no learning curve).) 9. Were the staff, place and facilities where the patients were treated appropriate for performing the procedure (e.g. access to back-up facilities in hospital or special clinic)? 10. Were any of the important outcomes considered (i.e. on clinical effectiveness, cost-effectiveness, or learning curves)? 11. Were objective (valid and reliable) outcome measures used, including satisfaction scale? 12. Was the assessment of main outcomes blind? 13. Was follow-up long enough (≥ 1 year) to detect important effects on outcomes of interest? 14. Was information provided on non-respondents, dropouts? (‘No’ if participants were those whose follow-up records were available (retrospective).) 15. Were the characteristics of withdrawals/dropouts similar to those that completed the study and therefore unlikely to cause bias? ('Yes’ if no withdrawal/dropout; ‘No’ if dropout rate ≥ 30% or differential dropout (e.g. those having most severe disease. 16. Was length of follow-up similar between comparison groups. 17. Were the important prognostic factors identified (e.g. age, duration of disease, disease severity)? (‘Yes’ if two or more than two factors were identified.). 18. Were the analyses adjusted for confounding factors?