Impact of usage of personal music systems on oto-acoustic emissions among medical students.

BACKGROUND: Intact hearing is essential for medical students and physicians for communicating with patients and appreciating internal sounds with a stethoscope. With the increased use of (PMSs), they are exposed to high sound levels and are at a risk of developing hearing loss. The effect of long term personal music system (PMS) usage on auditory sensitivity has been well established. Our study has reported the immediate and short term effect of PMS usage on hearing especially among medical professionals.

OBJECTIVE: To assess the effect of short term PMS usage on distortion product otoacoustic emissions (DPOAE) among medical professionals.

MATERIALS AND METHOD: 34 medical students within the age range of 17-22 years who were regular users of PMS participated in the study. All participants had hearing thresholds <15 dBHL at audiometric octave frequencies. Baseline DPOAEs were measured in all participants after 18 h of non-usage of PMS. One week later DPOAEs were again measured after two hours of continuous listening to PMS. DPOAEs were measured within the frequency range of 2 to 12 kHz with a resolution of 12 points per octave. Output sound pressure level of the PMS of each participant was measured in HA-1 coupler and it was converted to free field SPL using the transformations of RECD and REUG.

RESULTS: Paired sample t test was used to investigate the main effect of short term music listening on DPOAE amplitudes. Analysis revealed no significant main effect of music listening on DPOAE amplitudes at the octave frequencies between 2 to 4 KHz (t67 = -1.02, P = 0.31) and 4 to 8 KHz (t67 = 0.24, P = 0.81). However, there was a small but statistically significant reduction in DPOAE amplitude (t67 = 2.10, P = 0.04) in the frequency range of 9 to 12 kHz following short term usage of PMS. The mean output sound pressure level of the PMS was 98.29.

CONCLUSION: Short term exposure to music affects the DPOAE amplitude at high frequencies and this serves as an early indicator for noise induced hearing loss (NIHL). Analysis of output sound pressure level suggests that the PMSs of the participants have the capability to induce hearing loss if the individual listened to it at the maximum volume setting. Hence, the medical professionals need to be cautious while using PMS.