Auditory sensory impairment in children with oral clefts as indexed by auditory event-related potentials.

Children with nonsyndromic oral clefts and with the CATCH 22 syndrome (acronym for cardiac defects, abnormal faces, thymus hypoplasia, clefts, and hypocalcemia) display a range of language and learning disabilities, the neurofunctional bases of which are not yet understood. This review summarizes recent event-related brain potential (ERP) studies on central auditory processing in infants and children with different cleft types and presents an effort to integrate these ERP and earlier behavioral findings into a workable hypothesis on the mechanisms of cognitive impairment in the oral cleft population. The encoding of the acoustic sound features and the functioning of auditory sensory memory (ASM) were studied by recording cortical auditory ERPs. Tapped were two ASM functions: tone pitch discrimination and the duration of sensory memory for tone pitch. In infants with cleft palate, tone pitch discrimination was impaired at birth and at 6 months of age. In infants with cleft lip and palate, no ASM impairment was detected at either age. In school-aged children with clefts and CATCH 22 syndrome, the discrimination of tone pitch was intact under optimal stimulation conditions. However, in these children, shortened duration of ASM was observed, with the magnitude of its shortening covarying with cleft type and being most pronounced in children with CATCH 22 syndrome. The different types of ASM dysfunction found in children with different cleft types could not be accounted for by the peripheral hearing deficits. The relation between ASM dysfunction and known behavioral cognitive disability profiles in children with different cleft types suggests that ASM is implicated in language disabilities of children with oral clefts. Furthermore, it appears that the ASM impairment and oral clefting are linked in a comorbid fashion.