Epidemiology of permanent childhood hearing impairment in the Tyrol, 1980-94

In recent years the need for reliable data on permanent childhood hearing impairment (PCHI) has increased, owing to both scientific interest and practical aspects such as implementation of neonatal hearing screening. In order to obtain data about the epidemiology of PCHI in the Austrian state of Tyrol, the medical records of all hearing-impaired Tyrolean children born between 1980 and 1994 were researched. A total of 165 children with at least moderate hearing impairment in the better ear were registered, of whom 52.7% were found to be moderately hearing-impaired, 24.2% severely hearing-impaired and 23.0% profoundly hearing-impaired. Sensorineural hearing loss was observed in 87.3%, conductive hearing loss in 6.7% and mixed hearing loss in 6.1%. As for aetiology, non-syndromic hereditary hearing loss was diagnosed in 22% of the children and syndromic hearing loss in 8%. Congenital malformation of the ear was found in 3%. In 19% of the children, perinatal risk factors were seen, and in 10% a pre-, peri- or postnatal infection had occurred. Aetiology remained unknown in 36% of the children. The prevalence rate of newborn hearing impairment was 1.27/1000 newborns. The results are considered to fit well to the PCHI findings reported from other European regions.