ABSTRACT
Developmental dyslexia is a specific learning disorder that presents cognitive and neurobiological impairments related to different patterns of brain activation throughout development, continuing in adulthood. Lexical decision tasks, together with electroencephalography (EEG) measures that have great temporal precision, allow the capture of cognitive processes during the task, and can assist in the understanding of altered brain activation processes in adult dyslexics. High-density EEG allows the use of temporal analyses through event-related potentials (ERPs). The aim of this study was to compare and measure the pattern of ERPs in adults with developmental dyslexia and good readers, and to characterize and compare reading patterns between groups. Twenty university adults diagnosed with developmental dyslexia and 23 healthy adult readers paired with dyslexics participated in the study. The groups were assessed in tests of intelligence, phonological awareness, reading, and writing, as well as through the lexical decision test (LDT). During LDT, ERPs were recorded using a 128-channel EEG device. The ERPs P100 occipital, N170 occipito-temporal, N400 centro-parietal, and LPC centro-parietal were analyzed. The results showed a different cognitive profile between the groups in the reading, phonological awareness, and writing tests but not in the intelligence test. In addition, the brain activation pattern of the ERPs was different between the groups in terms of hemispheric lateralization, with higher amplitude of N170 in the dyslexia group in the right hemisphere and opposite pattern in the control group and specificities in relation to the items of the LDT, as the N400 were more negative in the Dyslexia group for words, while in the control group, this ERP was more pronounced in the pseudowords. These results are important for understanding different brain patterns in developmental dyslexia and can better guide future interventions according to the changes found in the profile.
ABSTRACT
Os problemas encontrados durante o processo de aprendizagem constituem uma das razões mais frequentes para a procura por atendimentos por psicopedagogos, psicólogos e fonoaudiólogos. Essas dificuldades têm sido analisadas em função de dois subtipos importantes: Dificuldades de Aprendizagem (DA) e Transtornos Específicos de Aprendizagem (TEAd), sendo a Dislexia do Desenvolvimento (DD) o transtorno com maior prevalência. Dessa forma, um dos aspectos importantes da avalição diagnóstica é o estabelecimento de diagnóstico diferencial. O presente estudo teve por objetivo caracterizar perfis de crianças e adolescentes com DD e DA em testes psicopedagógicos e neuropsicológicos, e compará-los com o perfil do grupo controle. Participaram 45 crianças e adolescentes divididas em três grupos: (G1) 21 sujeitos com DD; (G2) 10 sujeitos com histórico de DA, mas sem apresentar os critérios para diagnóstico do transtorno; (G3) 14 bons leitores, utilizados como grupo controle. Avaliaram-se as seguintes habilidades cognitivas: inteligência, atenção, consciência fonológica, fluência verbal, linguagem receptiva-auditiva, leitura e escrita. ANOVAs unifatoriais foram conduzidas e nos casos em que foram encontradas diferenças significativas entre os grupos, testes post hoc Bonferroni foram realizados. Os resultados apontaram que o grupo com DD apresentou maiores dificuldades em testes que avaliam a memória de trabalho e discriminação visual, além de erros específicos na leitura e escrita. Esse perfil cognitivo evidencia dificuldades específicas na leitura e nas habilidades cognitivas relacionadas a esse processo. Além disto, o estudo evidenciou a heterogeneidade do perfil de crianças com dislexia, bem como possíveis comorbidades com outros transtornos.
The problems encountered during the learning process are one of the most frequent reasons for seeking care by psychopedagogues, psychologists and speech therapists. These difficulties have been analyzed according to two important subtypes: Learning Difficulties (LD) and Specific Learning Disabilities (SLD), Developmental Dyslexia (DD) being the most prevalent disability. Thus, one of the important aspects of diagnostic assessment is the establishment of a differential diagnosis. The present study aimed to characterize the cognitive profiles of children and adolescents with DD and LD in psychopedagogical and neuropsychological tests, and to compare them with the control group. Participated a sample of 45 children and adolescents divided into three groups: (G1) 21 subjects with DD; (G2) 10 subjects with a history of LD, but without the diagnostic criteria for the disability; (G3) 14 good readers, used as a control group. The following cognitive abilities were evaluated: intelligence, attention, phonological awareness, verbal fluency, receptive-auditory language, reading and writing. One-way ANOVAs were conducted and in cases where significant differences were found between groups, post hoc Bonferroni tests were performed. The results indicated that the group with DD presented greater difficulties in tests that evaluate working memory and visual discrimination, besides specific errors in reading and writing. This cognitive profile shows specific difficulties in reading and cognitive abilities related to this process. In addition, the study evidenced the heterogeneity of the dyslexic children profile, as well as possible comorbidities with other disabilities.
