2.3 Data Extraction
Data extraction and efficacy evaluation criteria: Researches and statistics were extracted and assessed independently by two researchers (LUO and CHEN). The two researchers extracted the following data from each selected study: type of study, number of subjects with or without vertigo, age distribution, male/female ratio, treatment regimen, treatment period, definition of the average pure tone hearing threshold, standards for hearing amelioration, PTA or improvement rate after treatment, and follow-up time. The criteria for effective treatment were adopted according to the Siegel criteria: impaired hearing improvement >15 dB was considered an effective treatment, and impaired hearing improvement <15 dB was considered an ineffective treatment. We also compared the hearing recovery rate of patients suffering from SSHL among those with vertigo and those with SSHL among those free from vertigo and the rate of hearing recovery between each subgroup.