Otoacoustic emissions and auditory brainstem responses in patients with sudden sensorineural hearing loss. Do otoacoustic emissions have prognostic value?

BACKGROUND: Sudden sensorineural hearing loss (SSNHL) is a perplexing condition for patients and there are many controversies about its etiology, audiologic characteristics, prognostic factors, and treatment. METHODS: In this prospective study, we performed some audiologic tests, including PTA, lA, ABR, and OAE (TEOAE) before beginning treatment of 53 patients with SSNHL. We assigned the patients randomly to two treatment groups: oral steroids + acyclovir vs. intravenous urographin. Twenty-eight patients underwent Magnetic Resonance Imaging (MRI) of the Brain. RESULTS: Of 53 patients (22 female and 31 male), 22 (41.5%) had negative or no signal to noise ratio and overall correlation in TEOAE. Twenty-six patients (49%) had positive overall correlations less than 50%, and 5 patients (4.4%) had overall correlations 50%. Fifteen patients (28. 3%) responded completely or well, 20 (37.7%) responded partially, and 18 (33.9%) had poor or no response to the treatment. The mean values for overall correlation in 3 subgroups of patients (no response, partial response, and complete response) were - 3. 5% (± 1/16%), +11% (± 1/99%), and +36.6% (± 3/07%), respectively (P = 0.01). Twenty out of 52 patients had no reproducible wave in ABR (38.5%), and waves I, III, and V were absent in 40 (77%), 31 (59.6%) and 21 (40%) patients, respectively. There were some limitations (false positive and false negative results) in ABR use in our cases, but it may be useful in detecting site of lesion in SSNHL. Overall, according to the results of OAE, ABR, and brain MRI of these patients, 3 were affected by acoustic neurinomas, at least I had auditory neuropathy, and the site of lesion was cochlear in 6, and cochlear + retrocochlear in 13 patients. CONCLUSIONS: ABR has limitations for use in SSNHL and seems not to obviate the need for brain MRI, but may help in determining the site of lesions such as ischemia or neuropathy. Overall correlation (and SIN ratio) in TEOAE is a valuable prognostic factor in SSNHL, hence we recommend performing TEOAE in every patient with SSNHL.