Processamento temporal auditivo: relação com dislexia do desenvolvimento e malformação cortical

Abstract

Background: temporal auditory processing and developmental dyslexia. Aim: to characterize the temporal auditory processing in children with developmental dyslexia and to correlate findings with cortical malformations. Method: twenty school-aged children, ranging in age from 8 to 14 years were evaluated. These children were divided into two groups: the experimental group (EG) was composed by 11 children (eight were male) with developmental dyslexia and the control group (CG) was composed by nine normal children (six were male). After neurological assessment and verification of the intellectual level, language, reading and writing skills in order to determine the diagnosis, children underwent a peripheral audiological evaluation and Random Gap Detection Test and/or Random Gap Detection Test Expanded. Results: a statistically significant difference between children in the EG and CG were observed, with children in the EG presenting worst performances. Most of the children in the EG presented perisylvian polymicrogyria. Conclusion: children with developmental dyslexia may present temporal auditory processing disorders with deficits in phonological processing. Cortical malformations may be the anatomical substrate of these disorders. Key Words: Dyslexia; Hearing; Child. ResumoTema: processamento temporal auditivo e dislexia do desenvolvimento. Objetivo: caracterizar o processamento temporal auditivo em escolares com dislexia do desenvolvimento e correlacionar com malformação cortical. Método: foram avaliados 20 escolares, com idade entre 8 e 14 anos, divididos em grupo experimental (GE) composto por 11 escolares (oito do gênero masculino) com o diagnóstico de dislexia do desenvolvimento e grupo controle (GC) composto por nove escolares (seis do gênero masculino) sem alterações neuropsicolinguísticas. Após avaliações neurológica, neuropsicológica e fonoaudiológica (avaliação de linguagem e leitura e escrita) para obtenção do diagnóstico, os escolares foram submetidos à avaliação audiológica periférica e posteriormente aplicou-se o teste Random Gap Detection Test e/ou Random Gap Detection Test Expanded. Resultados: observou-se diferença estatisticamente significante entre os escolares do GE e GC, com pior desempenho para o GE. A maioria dos escolares do GE apresentou polimicrogiria perisylviana. Conclusão: escolares com dislexia do desenvolvimento podem apresentar alterações no processamento temporal auditivo com prejuízo no processamento fonológico. Malformação do desenvolvimento cortical pode ser o substrato anatômico dos distúrbios.

Processamento auditivo (central) em crianças com dislexia: avaliação comportamental e eletrofisiológica

“…The authors found significant differences for the assessment of temporal (central) AP between the groups, and a correlation between the test performance and words and non-words reading skills. Similar results were also found in other two studies that investigated temporal AP in children with dyslexia and in a control group (4,23) . The studies concluded that a deficit in the AP for short sounds may affect the perception of speech sounds an lead to a phonological awareness deficit and further reading problems.…”

Early neural disruption and auditory processing outcomes in rodent models: implications for developmental language disability

“…Histologic characteristics of these malformations strongly suggested a genesis in prenatal development, since they revealed abnormal placement of neurons within cortical layers (i.e., malformations including ectopias and microgyria). More recently, similar findings have been reported for individuals with developmental language impairment (Oliveira et al, 2007; Brandão-Almeida et al, 2008; Boscariol et al, 2010, 2011). Initially, these findings were thought to implicate a relationship between clinical diagnosis and specific disruption of fronto-temporal regions critical to language processing (since the distribution of anomalies in the affected brains was substantially greater in left perisylvian areas).…”

Speech Sound Processing Deficits and Training-Induced Neural Plasticity in Rats with Dyslexia Gene Knockdown

“…Individuals with this disorder have normal nonverbal intelligence, but score more than a standard deviation below their peers on reading tests [1], [3], [4]. Children and adults with dyslexia typically have deficits in phoneme perception and manipulation [5]–[8]. Even before learning to read, neural activation during phonological processing is impaired in young children at risk for dyslexia [9], which suggests that the neural abnormalities responsible for dyslexia are present from birth and do not reflect experience-dependent processes [10].…”