Diabetes impairs recovery from noise-induced temporary hearing loss.
OBJECTIVE
The purpose of this study is to investigate whether diabetes impairs the recovery from noised-induced temporary hearing loss.


METHODS
Twenty-eight male Wistar rats were divided into three groups: control, diabetes with insulin control (DI), and diabetes without insulin control (DM). Diabetes was induced by intraperitoneal injection of streptozotocin. All animals were exposed to white noise at 110 dB SPL for 8 hours. Auditory brainstem response (ABR) thresholds and distortion product otoacoustic emission (DPOAE) amplitudes were measured for all animals 1 day prior to noise exposure to obtain a baseline for hearing function, and then 1 hour, 1 day, 2 days, 4 days, 7 days, and 14 days after noise exposure.


RESULTS
One hour post exposure, ABR thresholds shifted markedly, and DPOAE was reduced similarly in all groups. Both ABR thresholds and DPOAE returned to the baseline in the control group at day 1, but they were not back to the baseline in the DM group even by day 14. Compared with the control group, the ABR threshold shifts and DPOAE returned to baseline more slowly in the DI group.


CONCLUSIONS
The present study suggests that diabetic patients need proper blood sugar control and probably need more effective preventive measures to preserve their hearing from the effects of noise. Laryngoscope, 2009.
Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei, Taiwan. cjhsu@ntu.edu.tw
Hung-Pin
HP
Wu
Tsun-Jen
TJ
Cheng
Ching-Ting
CT
Tan
Yueliang Leon
YL
Guo
Chuan-Jen
CJ
Hsu
D000818:Animals; D001305:Auditory Fatigue / Q000502:physiology*; D001786:Blood Glucose / Q000378:metabolism; D001933:Brain Stem / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D008297:Male; D009622:Noise / Q000009:adverse effects*; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose