[Hidden hearing loss and early identification]

Area of Science:

• Audiology
• Neuroscience
• Otolaryngology

Background:

• Hidden hearing loss (HHL) is characterized by impaired auditory function above typical hearing thresholds.
• Potential contributing factors include noise exposure, aging, and ototoxic drug damage, though their precise role in cochlear synaptic damage is unclear.
• Clinical signs include normal pure-tone audiometry (PTA) and auditory brainstem response (ABR) thresholds, but reduced amplitude of ABR wave I or electrocochleography (ECochG) at higher intensities, and poor speech recognition in noise.

Purpose of the Study:

• To investigate the clinical audiological characteristics of hidden hearing loss.
• To explore methods for early detection of HHL.

Main Methods:

• Utilized ultra-high frequency pure tone audiometry.
• Conducted objective audiological examinations including auditory brainstem response (ABR), electrocochleography (ECochG), and frequency-following response.
• Performed speech audiometry in noise and evaluated noise exposure through questionnaires.

Main Results:

• Identified characteristic audiological findings in HHL, such as normal PTA and ABR thresholds.
• Observed reduced amplitude of ABR wave I or ECochG at medium and high stimulation intensities.
• Noted decreased speech recognition ability in noisy environments.

Conclusions:

• Early detection of HHL is feasible using a combination of advanced audiological tests.
• These methods can identify subtle auditory deficits not apparent with standard hearing tests.
• Further research is needed to elucidate the mechanisms linking noise, aging, and drugs to synaptic damage in HHL.