Idiopathic sudden sensorineural hearing loss (ISSNHL) is a complicated hearing impairment with unclear etiology and unsatisfying treatment effects. Vestibular dysfunction like vertigo has been considered as a risk factor of profound hearing loss and poor prognosis in ISSNHL. Glucocorticoids, administered through oral or intratympanic way, is currently a regular and standard treatment for ISSNHL based on hearing outcome. However, little investigations have been conducted on recovery process and treatment effects of glucocorticoids on vestibular dysfunctions of ISSNHL. This study aims to evaluate the recovery pattern and possible process of vestibular system in ISSNHL with vestibular dysfunction, and to compare the efficacy of oral or intratympanic glucocorticoids in these participants.

A randomized, outcome assessor- and statistical analyst-blinded, controlled, clinical trial will be carried out. 72 patients complaining of vestibular dysfunction appearing as vertigo, dizziness, imbalance or lateropulsion with ISSNHL will be recruited and randomized into two arms of oral or intratympanic glucocorticoids therapy in 1:1 allocation. The primary outcomes will be subjective feelings evaluated by duration of vestibular dysfunction symptoms, dizziness-related handicap, visual analogue scale for vertigo, and objective vestibular function tests results assessed by sensory organization test, caloric test, video head impulse test and vestibular evoked myogenic potentials. Assessment will be performed at baseline and at 1, 2, 4, and 8 weeks post-randomization.

This study is designed as an 8-week, single-center, randomized, assessor- and analyst-blinded, controlled trial with two parallel interventional groups in a 1:1 allocation.

Patients will be recruited from outpatient clinics of the Eye and ENT Hospital of Fudan University in Shanghai, qualified with well-trained doctors, staff and required facilities for this clinical trial.

Inclusion Criteria:

1. Adults aged between 18 to 70 years old;
2. Diagnosed with unilateral ISSNHL according to the National Institute for Deafness and Communication Disorders (NICDC) criteria30: a decrease in hearing of ≥30 decibels (dB), affecting at least 3 consecutive frequencies occurring within a 72-hour period. Since premorbid audiometry is generally unavailable, premorbid hearing level will be defined as the opposite ear's thresholds in this condition;
3. Reported vertigo/dizziness/imbalance/lateropulsion and abnormal results in at least one of the vestibular function tests (including SOT, caloric test, vHIT, cVEMP, and oVEMP);
4. Onset of audio-vestibular symptoms occurred within 7 days;
5. Be willing to sign the informed consent of the study.

Exclusion Criteria:

1. Definite etiologies are found or highly suspected after clinical evaluations, such as vestibular schwannoma, stroke, trauma or demyelinating disease;
2. Diagnosed with a present or previous hearing or balance disorders which might be confused with ISSNHL (history of Meniere's disease, benign paroxysmal positional vertigo, vestibular neuronitis or vestibular migraine; history of otosclerosis; history of luetic, congenital or genetic hearing loss, etc.);
3. Hearing level (evaluated with PTA) in the unaffected ear is abnormal, so that a premorbid hearing level of the affected ear may not be estimated;
4. Suspected as central vestibular dysfunction, evaluated by present and previous medical history, physical examination and VNG;
5. Present with conditions contraindicated systemic glucocorticoids use, such as tuberculosis, hepatitis C or B infection, active herpes zoster infection or other known human immunodeficiency virus, pancreatitis, insulin-dependent diabetes mellitus, severe osteoporosis, chronic renal insufficiency or gastrointestinal ulcer;
6. A history of more than 3 days sufficient systemic glucocorticoids uses (≥1 mg/kg/d) within 3 months which may increase the risk of adverse effects. Considering that the glucocorticoids is a well-acknowledged standard treatment and that the patients might have probably received initial systemic glucocorticoids in emergency before outpatient appointment, we only excluded those who have received sufficient glucocorticoids (≥1mg/kg/d prednisone) for more than 3 days in previous 3 months;
7. Having received other systemic etiological treatments for ISSNHL (including hyperbaric oxcygen therapy (HBOT), thrombolytic drugs and antiviral drugs) which may confound the effects of study drugs. Patients who received only emergency or symptomatic treatments will not be excluded (i.e., betahistine, promethazine, diazepam, mecobalamin or ginkgo biloba leaves extracts);
8. Not appropriate for receiving vestibular function tests due to combination of fracture, inflammatory or suppurative ear disease, severe cervical spondylosis or severe psychotic disorders;
9. Multiple organ dysfunction or unstable vital signs;
10. Pregnancy or lactation;
11. Evaluated as unsuitable for the trial for any other reasons by investigators.