Cochlear Synaptopathy due to Mutations in OTOF Gene May Result in Stable Mild Hearing Loss and Severe Impairment of Speech Perception.
Rosamaria Santarelli, Pietro Scimemi, Marco Costantini and 3 others
PMID 33908410WHAT IT FOUND
Five patients with OTOF gene mutations had mild hearing loss but severe speech perception deficits.
Cochlear implants dramatically improved speech recognition to 90-95% in those tested, restoring synchronous nerve activation. This suggests implants are viable for mild hearing loss if speech perception is disproportionately poor.
Key findings
01Cochlear implants improved disyllable recognition scores to 90-95% and sentence recognition to 90-100% in OTOF patients with mild hearing loss.
02Electrophysiological testing showed that the compound action potential was replaced by a prolonged negative potential, indicating a failure of synchronous auditory nerve activation despite preserved cochlear function.
03Patients presented with mild hearing loss but severe speech perception deficits and language delay, a phenotype distinct from the temperature-sensitive or profound deafness forms of OTOF mutations.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study includes only five subjects, which is too small to establish general treatment guidelines. Only three of the five subjects received cochlear implants, so the implant outcome data is limited to this small subgroup. The study is observational and descriptive; there was no control group for the implant outcomes. Genotype-phenotype correlations for these specific novel mutations are based on a very small sample size.
Declared interests
The authors have no conflicts of interest to disclose.
The easy way to misread this
Do not assume that mild hearing loss on a standard audiogram indicates a good prognosis for speech development or that hearing aids are sufficient. This study shows that in OTOF-related synaptopathy, hearing thresholds can be near-normal while speech perception is severely impaired, and hearing aids were reported as ineffective in the adult subjects.