Effect of drill-induced noise on hearing in non-operated ear.
BACKGROUND
The aim of this study was to evaluate the effect of drill-generated noise on hearing loss in non-operated ear and if any, was temporary or persistent.


METHODS
In this prospective clinical study, 23 patients who had undergone mastoidectomy and normal contralateral hearing were enrolled. Patients were evaluated preoperatively and postoperatively (1 and 7 days) following surgery using low and high-frequency pure tone audiometry (PTA) and low and high-frequency transient evoked and distortion product otoacoustic emission (DPOAE) testing.


RESULTS
Comparing preoperative and 1-day after surgery, PTA averages were significantly different at low frequencies, but no statistical significant differences were observed at 0.25 KHz and high-frequencies. Comparing 1-day after surgery and 7 days after surgery showed that, PTA averages at 0.5, 2 and 2 KHz were significantly different with no significant differences at the other average of thresholds in low and high frequencies; PTA average at 1 KHz was significantly different with, no significant differences at the other averages of thresholds in low and high frequencies. DPOAEs showed a significant difference preoperative and 1-day after surgery, 1-day and 7 days after, but DPOAEs were not significantly different. Transiently evoked otoacoustic emissions (TEOAEs) had a significant difference preoperative and 1-day after surgery, 1-day and 7 days after but when comparing preoperative and 7 days after surgery, TEOAEs were not significantly different.


CONCLUSIONS
Drill-induced noise during ear surgery (mastoidectomy) can cause reversible changes in PTA, DPOAEs and TEOAEs in the non-operated ear.
Department of Otorhinolaryngology, Isfahan University of Medical Sciences, Isfahan, Iran.
Seyyed Hamidreza
SH
Abtahi
Department of Otorhinolaryngology, Isfahan University of Medical Sciences, Isfahan, Iran.
Alireza
A
Fazel
Department of Otorhinolaryngology, Isfahan University of Medical Sciences, Isfahan, Iran.
Mehrdad
M
Rogha
Communication Disorders Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
Mohamadhosein
M
Nilforoush
Department of Otorhinolaryngology, Isfahan University of Medical Sciences, Isfahan, Iran.
Reza
R
Solooki
Distortion product otoacoustic emissions; drill-induced noise; hearing loss; mastoidectomy; pure tone audiometry; transiently evoked otoacoustic emissions