Etiologies of hearing impairment among infants and toddlers: 1986-1987 versus 2001

Objective: This study compares etiological factors for hearing loss, relevant neuro-sensory impairments and demographics between two groups of children referred for early hearing habilitation in Israel. Group I was referred in the years 1986-1987 (n = 73) and group II was referred during 2001 (n = 73). Methods: Family history, pregnancy, risk factors, developmental milestones, medical history, auditory brainstem response, tympanometry, otoacoustic emissions and behavioral audiometric results were retrospectively retrieved in 2003 from medical records at the MICHA Society for Deaf Children in Israel. Results: New referrals per year have doubled themselves over the 15 years that elapsed between 1986-1987 and 2001. No changes in gender and age at time of admission were found. The prevalence of mild-to-moderate hearing loss was higher in Group II while severe and profound hearing loss was more prevalent in Group I. Assisted reproductive technologies were involved only in Group II. There were more twin births and post-natal hypoxia in Group II. Rh incompatibility was reported only in Group I. Severe hearing loss was associated with younger age at admission. No significant associations were found between age at admission and etiology with the exception of the fact that children with genetic background were admitted at an earlier age. Since no significant association between genetic background and severity of hearing loss was found, it is conclude that the association between severity of hearing loss and age at admission did not account for changes in etiology in our sample. Conclusions: Classic risk factors for hearing loss among infants and toddlers have not changed much over time, and the few changes that have been noticed are probably due to expanded medical knowledge and improved technologies.