SHIMP Findings in Individuals Using Personal Listening Devices

Listening to PLD at higher volume levels are known to cause subtle pre-clinical damage to the auditory system and vestibular end organs. Exposure to PLDs may also cause vestibular dysfunction much before the cochlear dysfunction. SHIMP is a newly described tool to assess the vestibulo-ocular reflex (VOR) gain suppression. With the premise that prolonged exposure to PLDs at high volume levels may cause vestibular dysfunction, and SHIMP being an early detector of vestibular dysfunction, the study was undertaken. The study aimed to describe the SHIMP test findings in normal hearing individuals with and without prolonged exposure to PLDs at > 60% of volume. A cross sectional comparative study was carried out on 128 participants with and without history of PLD exposure. Participants within the age range of 15-24 years and history of PLD usage at < 60% volume for < 1 year and at > 60% volume for > 1 year were recruited for the study. Output dBSPLs delivered by PLDs were measured using microphone in the ear method. Further, SHIMP was administered to assess the vestibular function. The dBSPL levels used by the participants of both the groups were within the DRC used for occupational noise exposure. Likewise, no statistically significant difference was observed between the two groups. Participants using PLDs with dBSPLs within the DRC may not be at a crucial risk. However, one must use precautionary measures to prevent any subclinical or long-lasting damage to the inner ear.