Sawako Masuda1, Satoko Usui2. 1. Department of Otorhinolaryngology, Institute for Clinical Research, National Hospital Organization Mie National Hospital, Tsu, Mie, Japan. Electronic address: masuda.sawako.tk@mail.hosp.go.jp. 2. Department of Otorhinolaryngology, Institute for Clinical Research, National Hospital Organization Mie National Hospital, Tsu, Mie, Japan.
Abstract
OBJECTIVES: The aim of the study was to clarify differences in the prevalence and features of bony malformations in inner ear between congenital unilateral sensorineural hearing loss (USNHL) and congenital bilateral sensorineural hearing loss (BSNHL). METHODS: We conducted a retrospective study of 378 consecutive infants referred from routine newborn hearing screening in the past 18 years. Clinical background, audiological data, and temporal bone computed tomography (CT) findings were analyzed. The prevalence of malformations between USNHL and BSNHL groups were compared using the Chi-square test. RESULTS: The proportion of family history of hearing loss was significantly higher in infants with BSNHL than in those with USNHL (26/107 [24.3%] vs. 4/105 [3.7%]; p = 0.0001). Temporal bone CT scanning revealed significantly a higher prevalence of inner ear malformations in infants with USNHL than in those with BSNHL (93/109 [85.3%] vs. 4/107 [3.7%]; p < 0.0001). The most frequent anomaly in USNHL was cochlear nerve canal stenosis (69.7%), followed by cochlear malformations (20.2%), and narrow internal auditory canal (17.4%). Four infants with BSNHL accompanied by inner ear anomaly had complications such as Down's syndrome, developmental delay, or epilepsy. CONCLUSIONS: The prevalence of bony malformations in inner ear and/or IAC was markedly higher in infants with congenital USNHL than in infants with BSNHL. Temporal bone CT scanning may help to clarify the etiology of congenital hearing loss, especially in USNHL.
OBJECTIVES: The aim of the study was to clarify differences in the prevalence and features of bony malformations in inner ear between congenital unilateral sensorineural hearing loss (USNHL) and congenital bilateral sensorineural hearing loss (BSNHL). METHODS: We conducted a retrospective study of 378 consecutive infants referred from routine newborn hearing screening in the past 18 years. Clinical background, audiological data, and temporal bone computed tomography (CT) findings were analyzed. The prevalence of malformations between USNHL and BSNHL groups were compared using the Chi-square test. RESULTS: The proportion of family history of hearing loss was significantly higher in infants with BSNHL than in those with USNHL (26/107 [24.3%] vs. 4/105 [3.7%]; p = 0.0001). Temporal bone CT scanning revealed significantly a higher prevalence of inner ear malformations in infants with USNHL than in those with BSNHL (93/109 [85.3%] vs. 4/107 [3.7%]; p < 0.0001). The most frequent anomaly in USNHL was cochlear nerve canal stenosis (69.7%), followed by cochlear malformations (20.2%), and narrow internal auditory canal (17.4%). Four infants with BSNHL accompanied by inner ear anomaly had complications such as Down's syndrome, developmental delay, or epilepsy. CONCLUSIONS: The prevalence of bony malformations in inner ear and/or IAC was markedly higher in infants with congenital USNHL than in infants with BSNHL. Temporal bone CT scanning may help to clarify the etiology of congenital hearing loss, especially in USNHL.