Abstract： Objective:To investigate the factors affecting the prognosis of sudden sensorineural hearing loss (SSNHL), so as to guide the comprehensive treatment combined with hyperbaric oxygen (HBO) on SSNHL.Methods:A retrospective analysis was conducted on 112 patients (115 ears) with SSNHL who were admitted to the Department of Hyperbaric Medicine of Beijing Chao-yang Hospital from June 2018 to September 2021. They were divided into effective group (cured + markedly effective + effective) and ineffective group. The factors, i. e., head magnetic resonance angiography (MRA) and neck vascular ultrasound, were compared between the two groups, and then binary logistic regression analysis was performed.Results:There were 45 cases (46 ears) in the effective group, 67 cases (69 ears) in the ineffective group, and the effective rate was 40.0%. After two courses of HBO treatment, ultrasound-assisted examination was performed. Internal carotid artery plaques were found in 53 cases and vertebral artery plaques were found in 12 cases. Head MRI showed white matter lesions (WMLs) in 53 cases and MRA showed intracranial vascular stenosis in 26 cases. Types of hearing loss curves: 12 cases (12 ears) were hearing loss in low tone frequencies, 16 cases (16 ears) were hearing loss in high tone frequencies; 44 cases (45 ears) were hearing loss in all tone frequencies; and 40 cases (42 ears) were total deafness. Hearing loss degree: 22 cases (22 ears) were mild, 29 cases (30 ears) were moderate, 17 cases (17 ears) were severe, and 44 cases (46 ears) were extremely severe. The time from onset to first treatment, the type of hearing loss, and the degree of hearing loss between the two groups were significantly different ( P<0.01). Logistic regression analysis showed that the type of hearing loss and the time from onset to first treatment were correlated with the prognosis of SSNHL ( P<0.01). Conclusion:The prognosis of SSNHL with early HBO intervention was better, while the prognosis of SSNHL patients with intracranial vascular stenosis was poor. The SSNHL patients with abnormal head MRA results need more attention.