A Prospective Assessment of Hearing Threshold Variability in Personal Listening Device Users

Background and aim The increasing use of personal listening devices (PLDs), particularly in-ear earphones, has raised concerns regarding their potential adverse effects on auditory health among young adults. Prolonged exposure to high-intensity recreational sound is considered a major risk factor for noise-induced hearing loss (NIHL). However, longitudinal evidence evaluating the combined influence of listening duration and volume intensity on hearing thresholds remains limited. This study aimed to prospectively assess hearing threshold variability among PLD users and examine the dose-dependent effects of earphone usage duration and listening volume over an 18-month period. Materials and methods A prospective longitudinal study was conducted among 100 participants aged 18-25 years over 18 months. Participants were categorized into four groups (n=25 each) based on daily earphone usage duration as follows: group A (1-2 h/day), group B (2-4 h/day), group C (>4 h/day), and group D (≤1 h/day/non-users; control). Each group was further stratified according to listening volume intensity (<60%, 60-80%, and >80% based on device volume settings). Baseline demographic details and otology symptoms were recorded using a structured questionnaire. Audiological evaluation was performed using pure-tone audiometry (PTA) at baseline and at 6, 12, and 18 months under standardized conditions. Statistical analysis was conducted using ANOVA and post hoc Tukey tests, with p≤0.05 considered statistically significant. Results A progressive increase in mean hearing thresholds was observed among earphone users over the 18-month follow-up period, with the highest deterioration noted in group C. Mean hearing thresholds increased from 13.36±3.90 dB to 14.92±4.41 dB in group A, from 15.42±4.69 dB to 18.42±4.86 dB in group B, and from 15.02±5.40 dB to 20.30±6.01 dB in group C, whereas minimal variation was observed in the control group (8.58±2.07 dB to 8.86±2.07 dB). Hearing threshold shifts demonstrated a dose-dependent pattern, with the highest shift observed in group C (-5.28±1.73 dB), followed by group B (-3.00±0.95 dB) and group A (-1.56±1.05 dB). Higher listening volume (>80%) was significantly associated with greater auditory decline and increased prevalence of otology symptoms such as tinnitus and ear pain. Significant intergroup differences were observed (p=0.001). Conclusion Prolonged and high-volume use of in-ear earphones was associated with progressive hearing threshold shifts among young adults, suggesting early auditory changes consistent with recreational noise exposure. Both listening duration and volume intensity emerged as important modifiable risk factors. The findings highlight the importance of safe listening practices, early auditory screening, and public health awareness strategies to reduce the potential risk of NIHL associated with personal listening device usage.