###### Abstract  
Idiopathic sudden sensorineural hearing loss (ISSNHL) refers to a loss of hearing, most commonly unilateral, that occurs suddenly (\(\lesssim\)72 h) with no identifiable cause or etiology. To date, there is no standard protocol to predict prognosis (hearing recovery) for patients with ISSNHL. However, studies have shown that changes in otoacoustic emissions (OAEs) often occur prior to changes in audiometric hearing thresholds. OAEs originate from the electrochemical motility of the outer hair cells (OHC) and reflect the integrity of the inner ear, specifically the cochlear amplifier. Therefore, OAEs may be useful as a prognostic predictive factor in patients with ISSNHL from the initial onset of symptoms through recovery. A systematic review of the literature was undertaken to assess the relationship between pure tone thresholds, OAEs, and subjective hearing improvement and/or recovery. Fourteen studies were identified for inclusion, and they overwhelmingly support the inclusion of OAEs in the protocol to monitor ISSNHL recovery. This finding supports the development of a standard diagnostic protocol that includes OAEs to predict patient hearing outcomes. diopathic sudden sensorineural hearing loss; otoacoustic emissions; hearing; pure tone audiometry; hearing recovery +
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include viral/bacterial infections, head trauma, autoimmune disease, ototoxic medications, circulation issues, neurological disorders, and inner ear disorders. A definitive etiology is only found in about ten percent of SSNHL cases, with the majority having an unidentifiable etiology, otherwise known as _idiopathic_ sudden sensorineural hearing loss (ISSNHL) [4]. The Massachusetts Eye and Ear Infirmary reports that a course of oral corticosteroids (prednisone or methylprednisone) is the standard treatment protocol for ISSNHL [5]. Steroids act to decrease swelling, while aiding the body in fighting illness in order to reduce overall inflammation. A typical course begins with a high initial dose followed by a taper over several days (e.g., 60 mg/day for 14 days followed by a five-day taper--50 mg, 40 mg, 30 mg, 20 mg, and 10 mg). This schedule is intended to create a balance between providing enough of the steroid to result in functional benefit without causing significant side effects. Administration of steroids should occur as soon as possible and is often recommended prior to receiving all test results, in the hopes of increasing effectiveness. Treatment that is delayed for more than two to four weeks is less effective in reversing permanent hearing loss [3]. Researchers at Massachusetts Eye and Ear Infirmary in 1980 reviewed the effectiveness of using a corticosteroid treatment for ISSNHL, and it has been widely used since. Over the past 15 years, administration of steroids through means of intratympan injections (through the eardrum and into the middle ear space) has gained wider use, with the goal being to introduce a higher drug concentration to the ear while minimizing exposure elsewhere in the body. Other potential treatment options include antiviral medication, drugs to improve blood circulation, hyperbaric oxygen treatments, or gas inhalation. It is important to note that none of these alternative treatment options have been shown to be more effective than the standard treatment protocol of oral steroid administration. Timely and rapid treatment of ISSNHL with a tapered course of oral steroids has been correlated with an improvement in hearing in roughly 80% of patients [1; 5]. Nearly all published studies have revealed a more positive outcome with earlier steroid treatment compared with delayed treatment. Current monitoring protocols use behavioral audiometry to track detriment, stability, and improvement in hearing sensitivity during and after treatment for ISSNHL.