Lasting auditory attention impairment after persistent middle ear infections: a dichotic listening study

Department ofPsychosocial Sciences, University of Bergen, Christiesgt. 12,N-5015 Bergen, Norway. E-mail: asbjornsen@psych.uib.noDichotic listening performance was studied in children who atan early age had undergone a myringotomy with insertion ofventilating tubes for persistent middle ear infections (otitismedia with effusion; OME) and compared with age-equivalent children who had no history of otitis media orhearing problems. The OME group consisted of 19 childrenwith a median age of 9 years; 15 of whom were right-handed,and 14 were boys. The comparison sample comprised 18children with a median age was 9 years 4 months. Handpreference and sex were matched with the OME group. Bothgroups were tested with dichotic listening to consonant–vowelsyllables and additional forced-attention tasks. Thecomparison sample showed a weak right-ear advantage, andage-adequate attentional modulations. The children in theOME group showed a strong right-ear advantage, but werenot able to modulate the ear advantage during directed-attention tasks. Models for interpreting the result arediscussed.Temporary hearing loss in preschool children may affect lan-guage development (Schlieper et al. 1985, Rach et al. 1988,Teele et al. 1990, Roberts et al. 1991). The consequencesmay be trivial with brief infections, whereas chronic orrecurrent infections are often followed by partial conduc-tive hearing loss, resulting in auditory deprivation (Howie1980), and delayed speech and language development(Schlieper et al. 1985, Maw et al. 1999). However, the effectsof early and recurrent otitis media with effusion (OME) onspeech and language development are far from clear.Adesman and coworkers (1990) showed that early lan-guage development (18 to 24 months) is associated with hear-ing status at 6 to 12 months of age. In addition, Teele andcolleagues (1990) found a positive correlation between dura-tion of middle ear effusion and tests of cognitive skills, lan-guage and speech performance, and school achievement.Rach and colleagues (1988) found no effect on verbal compre-hension but significantly lower scores for verbal expression inchildren with a history of OME. However, in a prospectivecohort study, Roberts and coworkers (1991) showed no rela-tion between OME and later language development. To date,no data have shown how OME affects the development of lan-guage laterality and auditory attentional skills. Dichotic listening implies presentation of two differentauditory stimuli simultaneously, one to each ear. The tech-nique has been used for the past three decades to study lan-guage processing in the brain, and has gained a reputation asa valid and reliable measure of auditory processing and func-tional lateralization. Specifically, it has been a popular proce-dure for assessing language lateralization (Kimura 1961,1967; Bryden 1988; Hugdahl 1988, 1995; Zatorre 1989;Hugdahl et al. 1997). The typical performance pattern is aright-ear advantage for verbal stimuli, and a left-ear advan-tage for non-verbal stimuli (voice-qualities, emotional con-tent, musical instruments, and so on; see Bryden 1988).In addition to being a reliable measure of functional later-alization of the brain, dichotic listening is also a valid proce-dure for assessing auditory selective attention (Broadbent1954; Bryden et al. 1983; Hugdahl and Andersson 1986;Asbjornsen and Bryden 1995, 1998; Asbjornsen andHugdahl 1995). Performance on directed-attention tasksdepends on the ability to detect the two different stimuli ineach consonant–vowel pair. Children with reading impair-ment may have problems with this task, resulting from a spe-cific temporal processing deficit which makes the stimulifuse into one sound (Asbjornsen and Bryden 1998).However, data have also shown superior auditory attentionalskills in children with reading impairment (Obrzut andBoliek 1988, Obrzut et al. 1997). These different findingsmay, however, be due to procedural differences. Little is known about the influence of early hearing prob-lems on language lateralization as measured using dichoticlistening paradigms. In one study, Moore and colleagues(1991) reported that children with temporary hearing losshad reduced binaural masking level differences (BMLD) com-pared with children without OME, and suggested that thesmall BMLDs in the OME group may be associated withimpaired auditory attention functions. However, studies havenot shown how the hearing problems affect the processing ofverbal, auditory stimuli. Furthermore, no information is avail-able on how language lateralization is related to other mea-sures of language skills.