Hearing loss in children in Østfold county 2000-09.

BACKGROUND: The Directorate of Health recommends hearing screening of all neonates with the aid of otoacoustic emissions (OAE). The goal is to achieve initiation of treatment before the child is six months old. Congenital hearing loss occurs in 1-3 per 1,000 newborns, and the purpose of this study was to identify the prevalence in a large Norwegian dataset.

METHOD AND MATERIAL: During the period 1 January 2000-31 December 2009, all children who were born in Østfold county, 29,485 neonates in total, were offered hearing screening with the aid of otoacoustic emissions. Those children in whom no emissions were detected were referred to the hearing centre. The dataset also includes children born during the same period who had normal emissions during their neonatal period, but later were diagnosed with hearing loss. The follow-up period of these children lasted until 31 December 2013.

RESULTS: Altogether 568 children were referred to the hearing centre after screening. Of these, 73 children underwent brainstem response audiometry under anaesthesia, and 31 (0.11%) were diagnosed with hearing loss through absence of emissions at birth. Eleven (35%) of these received their diagnosis before the age of six months. The median age of diagnosis decreased from 13 (7-74) to 6 (3-23) months, while their number increased from nine to 22 from 2000-04 to 2005-09. Hearing loss after normal otoacoustic emissions at the neonatal stage was diagnosed in ten children (0.03%) and the median age of diagnosis among these was 36 (18-86) months. After the introduction of automated auditory brainstem response audiometry (AABR) during sleep, the use of auditory brainstem response audiometry (ABR) under narcosis fell by half.

INTERPRETATION: The prevalence of hearing loss is equal to other Norwegian and international figures. The age of diagnosis decreased during the period. Otoacoustic emissions appear to be an effective screening method in paediatric wards. The use of automated auditory brainstem response audiometry reduces the need for testing under narcosis.