Received September 27, 2013 Revised February 10, 2014 Accepted February 12, 2014 Address for correspondence Byung don Lee, MD, PhD Department of OtolaryngologyHead and Neck Surgery, Soonchunhyang University College of Medicine, 59 Daesagwan-ro, Yongsan-gu, Seoul 140-743, Korea Tel +82-2-709-9363 Fax +82-2-709-9134 E-mail bdlee12@schmc.ac.kr Background and ObjectivesZZThe plasma stress-related hormonal [cortisol, growth hormone, prolactin, antidiuretic hormone (ADH), adrenocorticotropic hormone (ACTH)] levels have been reported to be elevated in sudden sensorineural hearing loss (SSNHL) patients. However, little is known regarding the mechanisms related with the elevation of stress-related hormonal levels in SSNHL. Therefore, we measured the level of plasma stress-related hormones in SSNHL patients and in normal persons to demonstrate the association between the stress-related hormones and SSNHL. Subjects and MethodZZStress-related hormonal levels were measured from 68 patients who were diagnosed with SSNHL. These values were compared with the stress-related hormonal levels of 24 healthy control subjects. ResultsZZThe plasma ADH levels was significantly higher in SSNHL group compared with that in their normal control group, as shown by their respective values, 4.46 [95% confidence interval (CI): 3.80-5.24 pg/mL] and 3.05 (95% CI: 2.34-3.98 pg/mL). The values for plasma cortisol, growth hormone, and ACTH levels whose values were 2.07 (95% CI: 1.65-2.61 μg/L), 0.20 (95% CI: 0.14-0.29 μg/L), and 12.79 (95% CI: 11.16-14.66 pg/mL), respectively, were significantly lower in the SSNHL group than those in the normal control group whose values were 7.86 (95% CI: 5.33-5.24 μg/L), 0.61 (95% CI: 0.36-1.04 μg/L), 18.48 (95% CI: 14.9922.78 pg/mL), respectively. But there was no significant difference in prolactin between the two groups. ConclusionZZThis study demonstrates a possible role of stress-related hormones in the pathogenesis of SSNHL. However, only ADH level was higher than the control group. Furthermore, ACTH, growth hormone and cortisol levels were lower than the control groups. This means ADH, growth hormone, cortisol, ACTH levels are related with SSNHL. However, the impact of this hormone on the inner ear and endolymph homeostasis is still unknown. Further investigation is necessary to identify the action mechanism of these hormones in the inner ear. Korean J Otorhinolaryngol-Head Neck Surg 2014;57(6):373-8