From devices to biology: Rethinking congenital hearing loss care

Modern pediatric hearing care has evolved in distinct phases: from earlier diagnosis, to powerful devices, and now toward precision biology. Here's how each era reshaped outcomes and why etiology-driven care is defining the future of hearing restoration in children.

The first era: Early diagnosis

The first big leap was not a technology inside the ear. It was diagnosing the afflicted pediatric population earlier. Universal newborn hearing screening changed the entire pipeline. Earlier detection meant earlier language access. It also exposed a truth clinicians still deal with: Diagnosis does not equal etiology.

Julie Wei, MD, director of otolaryngology at Akron Children's Hospital, discussed early testing as one of the biggest practical improvements in congenital hearing care in the last 10 years.

With reference to newborn CMV testing at birth, she noted that “about 1 in 5 babies with congenital CMV infection (cCMV) will have birth defects and long-term health problems. Testing for cCMV is not yet universal, but when identified, systemic antiviral therapy may prevent and/or mitigate disease onset, including developing of SNHL [sensorineural hearing loss].”

The second era: Devices

The use of devices defined the next era.

• Hearing aids improved in signal processing, fitting precision, and pediatric verification methods.

• Cochlear implants moved earlier in life and became standard for severe-to-profound congenital SNHL.

• Bilateral implantation, hybrid educational models, and better mapping strategies improved outcomes.

Commenting on cochlear implantation (CI), Dr. Wei explained, “Cochlear implantation substantially enhances auditory and speech perception capabilities in patients with auditory neuropathy and internal auditory canal stenosis. Long-term asymmetric hearing loss may influence outcomes after cochlear implantation, and as CI candidacy expands in both adults and children, there may be areas identified of limited benefit with respect to speech perception and patient-reported experience.”

But the device era had limits. Even with optimal implantation and therapy, performance varied widely. Etiology drives part of that spread, especially in auditory neuropathy phenotypes, cochlear nerve deficiency, and syndromic conditions.

The new era: Precision biology

The biology-based era started when etiology became actionable.

Dr. Wei also considered this as one of the biggest practical improvements in recent times, particularly the availability of genetic testing for SNHL. “This is crucial,” she said, “as all parents want answers and to understand why their child has hearing loss if and when CT/MRI imaging does not show any anatomical abnormalities.” 

Three developments made the new era possible:

1. Genetics became clinically scalable. Next-generation sequencing panels moved from research to clinic. For bilateral congenital SNHL, genetic diagnoses became routine in many centers.

2. Inner-ear delivery became realistic. Intracochlear delivery is invasive, but familiar to pediatric otologic surgeons. The surgical route is already used for implantation. This lowers the barrier to localized biologic therapy.

3. Gene therapy matured as a platform. AAV-based therapies in other fields helped normalize regulatory and manufacturing pathways.

OTOF-mediated DFNB9 sits near the top of the list of potentially treatable conditions because it is monogenic, and the defect sits at synaptic transmission rather than cell loss. That increases the plausibility of functional restoration.^[]

Reports coming out of clinical studies have already attested to the viability of this approach.  Regeneron’s OTOF-targeting program has  accomplished improved hearing in most treated children, with some reaching normal or near-normal hearing in follow-up evaluations.^[]

The clinical implications extend to more than one gene. Once an AAV strategy works for a large-gene target in cochlear cells, the field gains a template for other etiologies.

Looking to the future

Despite the progression of advances in the field, the evolution of the understanding and treatment of congenital hearing loss is not linear. Devices remain the standard of care for most patients today. A biology-based future could segment the population as follows:

• Reversible synaptopathies, where gene replacement restores function

• Hair-cell loss, where regeneration strategies are needed

• Neural etiologies, where implants remain the best tool

• Syndromic disease, where hearing is one piece of a multisystem plan