Does the Cause of a Hearing Loss Affect the Success of a Cochlear Implant?

In the United States, most childhood-onset, bilateral sensorineural hearing loss is genetic, with more than 120 genes and thousands of different alleles (i.e., one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome) known. Genetic diagnosis can inform progression of hearing loss, indicate potential syndromic features, and suggest best timing for individualized intervention.

Carlson et al. (2023) conducted a cross-sectional study through genomics and a retrospective cohort analysis using audiological data from 2019 to 2022. Subjects were 449 children from 406 families with bilateral sensorineural hearing loss identified before 18 years of age. Their goal was to identify the genetic cause(s) of childhood onset hearing loss, report on severity and progression of hearing thresholds, and determine cochlear implant success through pediatric and adult speech-perception tests. Data were evaluated over a six-month period.

Genetic causes of hearing loss were revealed in 52 percent of those tested. Rates of genetic diagnosis were similar for children of all ancestries. Causal variants occurred in 43 different genes. Hearing loss severity, affected frequencies, and progression varied by gene(s). Five genes were associated with progressive hearing loss (more than 10 dB per decade).

For all children with cochlear implants, outcomes on adult speech-perception tests were greater than pre-implanted levels. The degree of success varied substantially by genotype. Adjusting for age at implant and time interval since implant, speech perception was highest for children with hearing loss due to the melanocyte inducing transcription factor (MITF) gene or the transmembrane serine protease 3 (TMPRSS3) gene.

The authors concluded that genetic identification has seen technological advances in recent years and always should be integrated into the medical and audiological care for childhood-onset hearing loss.

Reference

Carlson RJ, Walsh T, Mandell JB, et al. (2023) Association of genetic diagnoses of childhood-onset hearing loss with cochlear implant outcomes. JAMA Otolaryngol Head Neck Surg. Published online.