Evaluating cochlear implant outcomes in DFNA9 subjects: a comprehensive study on cerebral white matter lesions and vestibular abnormalities

Purpose

This study assessed whether the Fazekas score could account for the variability in cochlear implantation (CI) outcomes among individuals with DFNA9 and evaluated signal loss in the semicircular canals (SCCs) on magnetic resonance imaging (MRI) among individuals with DFNA9.

Method

This retrospective cross-sectional study included CI recipients with DFNA9. Pre-implantation MRI-scans were reviewed to determine the Fazekas score, localizing and grading cerebral white matter lesions (WML), and identify abnormalities in the SCCs. CI performance was assessed by evaluating phoneme scores one year post-implantation. The function of the SCCs was evaluated using rotatory chair testing with electronystagmography (ENG) and the video Head Impulse Test (vHIT).

Results

Forty-five subjects (49 ears) were enrolled. The phoneme scores significantly improved from 35% (IQR 11–50) pre-implantation to 84% (IQR 76–90) one year post-implantation. No correlation was observed between the Fazekas score and the one-year post-implantation phoneme score (r_sp=0.003, p = 0.986). Signal loss in at least one SCCs was detected in 97.7% of subjects and 77.8% of ears. There was no correlation between vestibular test results and fluid signal loss in the SCCs on MRI.

Conclusion

Most individuals with DFNA9 show improved speech recognition with CI. The observed variability in CI outcomes was not linked to the Fazekas score. Additionally, our study confirms a high prevalence of focal sclerosis in DFNA9. Recognizing the limitations of this study, further research is needed to explore the predictive role of the Fazekas score on CI outcomes and its relationship with vestibular function.