Late diagnosis of congenital sensorineural hearing impairment: why are detection methods failing?

This study was designed to look in detail at the paths to diagnosis for a group of 197 children with congenital sensorineural hearing impairment (SNHI), who were diagnosed between 1989 and 1991 in the state of Victoria, Australia. Despite the existence of universal infant screening at 7-9 months by distraction test or questionnaire, the median age at diagnosis for the study group was 18.0 months, with median age at aid fitting of 20.8 months, and median age at commencement of specialised intervention programmes of 22.3 months. Parent questionnaires completed for 143 (73%) of these children showed that 49% had known risk factors for hearing loss yet only 20% of them had been referred for audiological assessment before the 7-9 month screen. Only 63% of those eligible for the 7-9 month screen had received it. Of those children who were screened by distraction test 46% passed as did 57% of those screened by questionnaire. Twenty four parents (17%) described how they had initially 'denied' their own observations of their infants' abnormal hearing behaviour. When concerns were raised with professionals, 10% of parents were falsely reassured without audiological assessment. Detection methods are failing through a combination of poor screen test efficacy, incomplete population coverage, and parental and professional denial.