2.1 Data sources and search strategy
We screened for researches in Web of Science, PubMed, EMBASE, and other databases from January 1st, 2000 to September 1st, 2023 that involved assessment of the prognostic relationship between vertigo and sudden sensorineural hearing loss. The search terms used were ”sudden hearing loss OR deafness, sudden OR sudden deafness OR hearing loss, sudden; vertigo OR vertical OR spinning sensation OR sensation, spinning OR sensations, spinning OR spinning sensations; and the third, both strings.”