Effects of Recurrent Acute Otitis Media on Cortical Speech-Sound Processing in 2-Year Old Children

Abstract

<div> Objectives: To investigate at the age of 2 years the effects of childhood</div> <div> recurrent acute otitis media (RAOM) on central auditory processing by</div> <div> using cortical event-related potentials elicited by syllable stimuli.</div> <div> Design: During a 1-year period, 22- to 26-month-old children fulfilling</div> <div> the criteria for tympanostomy tube insertion in Oulu University Hospital,</div> <div> Oulu, Finland, were recruited to the RAOM group (N = 20). The control</div> <div> group (N = 19) was matched by age, sex, and mother&rsquo;s educational level.</div> <div> In both groups, children were typically developing and had no family history</div> <div> of language disorder or developmental language problems. Finnish</div> <div> syllables /ke:/ and /pi:/ as standards and their variants with changes in</div> <div> frequency, intensity, vowel, consonant, and vowel duration as deviants</div> <div> were used to record P1, N2, and mismatch negativity (MMN) responses</div> <div> in the multifeature paradigm. The clinically healthy ears at the time of</div> <div> registration were a prerequisite for the participation.</div> <div> Results: Children with RAOM and their controls showed the age-typical</div> <div> P1 and N2 responses with no differences in the amplitudes or latencies</div> <div> between the groups, which suggests unaffected basic encoding of</div> <div> sound features and sound representation formation. However, the groups</div> <div> showed different auditory discrimination profiles. In children with RAOM,</div> <div> frequency and vowel MMN amplitudes were increased. Furthermore, the</div> <div> MMN latency for the frequency change was shorter and the frequency</div> <div> MMN amplitude lateralized to the left hemisphere in the RAOM group</div> <div> instead of an adult-like right-hemispheric lateralization observed in the</div> <div> controls. The children with RAOM had a more anterior MMN amplitude</div> <div> scalp distribution for the intensity change than control children. In</div> <div> addition, the MMN amplitude elicited by consonant change was evenly</div> <div> distributed unlike in controls, who had a left-side preponderant lateralization.</div> <div> Taken together, these results suggest an elevated responsiveness</div> <div> for frequency, vowel, and intensity changes, and an immature pattern of</div> <div> discriminating small speech sound contrasts in children with RAOM.</div> <div> Conclusions: The results suggest that childhood RAOM does not affect</div> <div> the central auditory pathway integrity or sound encoding. However,</div> <div> RAOM may lead to aberrant preattentive discrimination of sound features</div> <div> even when the peripheral auditory input is normal. These results</div> <div> are clinically significant because even transient problems with auditory</div> <div> processing may delay language development.</div>