Acoustic trauma inducing ‘low frequency’ sensorineural hearing loss; A
cross-sectional study among medical students using Pure Tone Audiometry
Abstract
Objectives: This study aimed to ascertain current practices prevalent
among medical students using electroacoustic devices. We also aimed to
determine pattern and frequency of hearing loss among medical students.
Design: Cross-sectional Participants: Students of 3rd year and 4th year
MBBS at Jinnah Sindh Medical University, Karachi, Pakistan were
included. Data collection dated from December 2019 till February 2020
using convenience sampling technique. Setting: Students were invited to
ENT OPD, Jinnah Postgraduate Medical Centre, Karachi. Through a
structured proforma, we recorded practices regarding electroacoustic
devices. We investigated hearing of medical students by tuning fork
tests and Pure Tone Audiometry. Main Outcome Measures: Using SPSS
software version 23 we applied Chi square test, Pearson correlation and
independent t test at 95% CI and p=<0.05 as significance
level. Results: A total of 221 students fulfilled inclusion criteria.
96.4%(n=213) regularly used electroacoustic devices. Students mostly
used insert type earphones connected with a smartphone. More than 30%
of medical students demonstrated low frequency (0.25-0.5kHz)
sensorineural hearing loss (SNHL). Pearson correlation yielded strong
positive correlation with hearing loss and years of
exposure(p=<0.001). Male students used electroacoustic devices
more frequently than female students(p=0.01). However, we did not
observe significant difference between their mean thresholds.
Conclusion: Acoustic trauma has been conventionally described to affect
higher frequencies. We found low frequency SNHL among majority of
students. This indicates that specific type of acoustic trauma can
affect particular frequencies on audiogram. KEY WORDS: Low frequency
hearing loss, medical students, Pure Tone Audiometry, personal listening
devices, hearing thresholds, noise induced hearing loss, sensorineural
hearing loss