Binaural unmasking returns to normal in teenagers who had otitis media in infancy

Several studies have shown that the binaural masking level difference (MLD) is reduced in children who have a history of recurrent otitis media (OM) in infancy. In this prospective study we have retested the MLD in two groups of teenagers who were originally tested 6 years ago. Members of one of these groups (OM group; n = 26) had at least 5 recorded episodes of OM before the age of 5 years. The other group (controls; n = 17) had no known history of OM. The mean MLD (500-Hz tone in a narrow band noise masker) of the OM group was, at 6-12 years of age, significantly lower than that of the controls. In this study (at ages 12-18 years), we found no difference between the mean MLDs of the OM and control groups. These results show that the reduced MLD that occurs following OM in infancy can recover in later childhood.