Electrophysiological Evidence of Early Auditory Dysfunction in Personal Listening Device Users: Insights from ABR with Ipsilateral Masking

<b>Background:</b> Recreational noise exposure from personal listening devices (PLDs) may lead to hidden hearing loss (HHL), affecting auditory nerve function despite normal pure-tone audiometry (PTA) and otoacoustic emissions (OAE). Subclinical auditory damage at the synaptic level often goes undetected by conventional assessments, emphasizing the need for more sensitive measures. Recorded click ABR in the presence of various levels of ipsilateral maskers for the better identification of auditory damage at the synaptic level. These results could help to develop a better objective diagnostic tool that can detect hidden hearing loss. <b>Objective:</b> To examine the effects of PLD usage on extended high-frequency audiometric thresholds and on click-evoked auditory brainstem responses (ABR) with and without ipsilateral masking in individuals with normal hearing. <b>Materials and Methods:</b> Thirty-five young adults aged 18-35 years (18 PLD users, 17 controls) with clinically normal hearing were recruited. Extended high-frequency audiometry (EHFA) was conducted from 9 to 16 kHz. Click-evoked ABRs were recorded at 80 dB nHL under unmasked and ipsilateral broadband noise-masked conditions at 50, 60, and 70 dB SPL. ABR analyses included absolute and relative amplitude (V/I) and latencies of waves I, III, and V. <b>Results:</b> PLD users demonstrated significantly elevated extended high-frequency thresholds compared to controls. ABR analyses revealed reduced Wave I amplitudes across stimulus conditions in PLD users, while Wave V amplitudes were largely preserved, resulting in consistently higher V/I amplitude ratios under masked conditions. No group differences were observed for Wave III amplitudes or absolute/interpeak latencies, except for a modest prolongation of I-III latency at one masker level in PLD users. <b>Conclusions:</b> Conventional audiological tests may not detect early auditory damage; however, extended high-frequency audiometry and ABR with ipsilateral masking demonstrate greater sensitivity in identifying noise-induced functional changes within the auditory brainstem pathways.