Seoul National University Bundang Hospital (SNUBH) researchers have found that MRI-based measurement of auditory nerve atrophy can effectively differentiate adult auditory neuropathy spectrum disorder (Post-ANSD) from ordinary sensorineural hearing loss.

A team, led by Professor Choi Byung-yoon and specialist Shin Kyu-ha of the Department of Otorhinolaryngology at SNUBH, reported that unlike common hearing loss, which arises from cochlear hair cell damage and primarily reduces sound volume, auditory neuropathy impairs the transmission of sound signals from the auditory nerve to the brain, leading to disproportionately poor speech recognition.

The study emphasized that hearing aids are ineffective for adult auditory neuropathy, since amplification cannot compensate for faulty neural transmission.

Cochlear implants remain the only effective treatment, yet diagnosis is often delayed because patients retain some hearing, creating uncertainty over when surgery is necessary.

Many patients are misdiagnosed as having ordinary hearing loss and waste valuable time with ineffective hearing aids, missing the critical window for cochlear implantation.

The SNUBH team analyzed 61 patients aged 40 to 65 who underwent cochlear implantation at the hospital between 2017 and 2023.

MRI scans revealed that auditory neuropathy patients exhibited significant auditory nerve atrophy from early stages, particularly when damage extended beyond the synaptic junctions where neural signaling occurs.

While hearing tests showed similarities between the two conditions, MRI provided clear distinctions in nerve structure and damage location.

Crucially, the researchers confirmed that patients with marked auditory nerve atrophy could still regain speech comprehension if cochlear implantation was performed before the nerve degenerated irreversibly.

“These findings provide important diagnostic evidence to identify adult auditory neuropathy early and avoid wasted time on ineffective hearing aids,” the team said.

Professor Choi also said, “Progressive auditory neuropathy accounts for about 10 percent of all hearing loss cases, and auditory nerve atrophy can progress rapidly even before severe hearing decline.”

Earlier consideration of cochlear implantation compared to typical hearing loss cases is essential to achieve optimal treatment outcomes, Choi added.

The study, supported by the Ministry of Education and the Ministry of Trade, Industry and Energy, was published in the latest issue of Otology & Neurotology.