Evoked potential correlates of temporal auditory processing disorders and developmental language delay in school-agend children
Date
2012
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Abstract
The theory that a fundamental deficit in the cortical processing of rapid, successive sensory events underlies neurodevelopmental disorders such as specific language impairment (SLI) and specific reading disability ( dyslexia) has been intensely debated for over 30 years. The present study compares behavioural performance on a range of auditory processing, reading/language, speech perception, auditory and visual temporal measures, with multichannel obligatory auditory evoked potential (AEP) responses to continuous and interleaved click train stimuli, and a /ba./-/pa./ speech continuum in normal learning children vs. children with learning disabilities ( aged 9 -17 years). In spite of strong behavioural evidence for temporal and auditory processing difficulties in the experimental group, the AEP results show a maturational lag in younger subjects but neural representation for temporal events of 19 ms duration for groups of four click trains, and 20 ms for voice-onset time gaps in a speech continuum, which is below the categorical boundary for perception of consonants. The double-on response to voiceonset time was not readily identifiable in many children. Adaptation of the auditory response was essentially normal in all children but there were subtle effects suggesting that refinements in the auditory response were still occurring. Maturational status of the brain profoundly influences the morphology of AEPs, especially in children 12 years and under. Experimental and control children did not differ significantly on many of the electrophysiological measures but younger experimental children differed from adult endpoints. Older experimental children differed frequently from adults in the N2 component. Relationships between the behavioural and electrophysiological measures were linked through maturational processes. Although rapid repetition rates are more challenging for an immature auditory system, there are subtle changes occurring into adolescence even for slower stimuli rates, paralleling the lengthy development of auditory pathway, which is contrary to the temporal processing hypothesis. The presence of a co-occurring auditory processing impairment is consistent with abnormal cortical maturation and not a temporal processing disorder of auditory cortex.
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Bibliography: p. 264-287
Some pages are in colour.
Includes copies of ethics approval and copyright permissions. Original copies with original Partial Copyright Licence.
Some pages are in colour.
Includes copies of ethics approval and copyright permissions. Original copies with original Partial Copyright Licence.
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Citation
Muir, P. J. (2012). Evoked potential correlates of temporal auditory processing disorders and developmental language delay in school-agend children (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/4928