Unilateral Sensorineural Hearing Loss (USNHL): A Retrospective Study of Incidence

This retrospective study was carried out to know the incidence of unilateral sensorineural hearing loss (USNHL) (type and degree). (1) To know the incidence of USNHL (other ear being normal) in patients undergoing Pure Tone Audiometry (PTA) for hearing loss (HL). (2) To establish the type and degree of USNHL in patients. Study was conducted over a period of more than 4 years to find out the incidence and pattern of USNHL (other ear being normal) in the patients attending ear, nose, and throat outpatient department (OPD) with a complaint of HL. Pure tone audiometry data of 10,000 cases between August 2014 and December 2018 with HL were analyzed for this study. Demographic characteristics were compared with types and degrees of unilateral sensorineural hearing impairment. A total of 10,000 OPD cases who had a complaint of HL and had undergone pure tone audigram (PTA) in a period of more than 4 years in the Department of Otorhinolaryngology and Head and Neck Surgery were studied. SNHL type was the highest with 3935 cases (39.3%). Out of 3935 cases of SNHL, 1436 (36.50%) were USNHL-out of which, only 872 cases (60.72%) had USNHL with other ear being normal; this constituted the study group, i.e., 872 cases (8.72%) out of 10,000 PTA and 872/3935 (22.16%) of SNHL cases. Hence, incidence of USNHL (with other ear being normal) is 8.72% among all cases of HL and 22.16% among cases of SNHL. Age of cases ranged from 8 to 76 years (mean age - 39.5 years). Male:Female ratio was 1.6:1.0. Both ears were almost equally involved. 35.6% cases had profound (> 90 dB) hearing loss, followed by mild (25-40 dB) in 32.1%.