Congenital unilateral hearing loss : characteristics and etiological analysis in 121 patients

Objective: To describe the characteristics and etiological analysis in patients with congenital unilateral hearing loss. Study design: Retrospective cohort analysis. Setting: Tertiary referral center. Patients: Children with permanent congenital unilateral hearing loss born between 2007 and 2018. Patients were referred after universal newborn hearing screening or by a colleague to confirm the diagnosis and perform etiological examinations. Main outcome measures: Hearing loss type, severity, and evolution linked with the results of etiological testing. Results: In the 121 included children, aural atresia is the leading cause of congenital unilateral hearing loss (32%), followed by structural anomalies (19%) and cCMV (13%), whereas 24% remained idiopathic after etiological work-up. Severity is mainly moderately severe (33% with 56-70 dB hearing loss, majority aural atresia) or profound (31% with > 90 dB hearing loss, predominantly cochlear nerve deficiency). Syndromic features were present in 26%. Although discussed with all parents, only 26% of the children regularly used hearing amplification. Conclusions: Congenital conductive unilateral hearing loss is mainly caused by aural atresia, which proportion in congenital unilateral hearing loss proved higher than previously reported. Cochlear nerve deficiency and cCMV are the predominant etiologies of congenital unilateral sensorineural hearing loss. Etiological work-up in affected patients is mandatory as it might impact the approach, and syndromic features should be actively searched for