Deficits in dyslexia: barking up the wrong tree?

Associação da dislexia do desenvolvimento com comorbidade emocional: um estudo de caso

OBJETIVO: analisar características em um caso de dislexia com depressão infantil. MÉTODOS: descrição dos resultados da avaliação interdisciplinar em um caso com dislexia e depressão. Participou deste estudo uma criança, do gênero masculino, com 10 anos e 7 meses, cursando o 4º ano do Ensino Fundamental em uma escola pública. RESULTADOS: os resultados deste estudo evidenciaram alterações não somente na linguagem, em que há dificuldades no processamento fonológico da informação, como também na atenção e funções executivas e quadro comórbido de depressão infantil. CONCLUSÃO: o estudo revelou a necessidade da avaliação de uma equipe interdisciplinar para um diagnóstico preciso e, conseqüentemente uma melhor intervenção em crianças com dislexia e suas comorbidades.

Intact first- and second-order implicit sequence learning in secondary-school-aged children with developmental dyslexia

We examined the influence of task complexity on implicit sequence learning in secondary-school-aged children with developmental dyslexia (DD). This was done to determine whether automatization problems in reading extend to the automatization of all skill and depend on the complexity of the to-be-learned skill. A total of 28 dyslexic children between 12 and 15 years and 28 matched control children carried out two serial reaction time tasks using a first-order conditional (FOC) and second-order conditional (SOC) sequence. In both tasks, children incidentally learned a sequence of hidden target positions, but whereas FOC sequence learning could be based on knowledge about the immediate preceding position, SOC sequence learning required more complex knowledge about the previous two positions. The results demonstrated that sequence learning was highly comparable in dyslexic and control children, regardless of the sequence complexity. This shows that implicit sequence learning, as manifested in the present study, is maintained in DD and is unrelated to task complexity. We suggest that previous reports of sequence-learning deficits in DD can be accounted for by attenuated explicit sequence learning, possibly related to malfunctions in prefrontal processing. The present findings indicate that deficits in skill learning and automatization in DD are not general in nature, but task dependent.

Unimpaired implicit learning in children with developmental dyslexia

Children with dyslexia have consistently been found to have a variety of deficits in motor, cognitive, and sensory processes; however, the few studies that have been reported of the implicit learning ability of these children have produced conflicting results. The present study aimed to investigate the implicit learning abilities of children with developmental dyslexia using a simple cued reaction time task which has not been studied with this group previously. Twenty-three children with developmental dyslexia and 37 normally developing children, between the ages of 8 and 10 years, participated in the task. The results were consistent with the hypothesis in demonstrating that, despite an overall slowing in response times, dyslexic children show the same degree of implicit learning as normal readers, thus, providing evidence for an unimpaired implicit learning mechanism in dyslexic individuals. These results hold implications for the underlying mechanisms of learning, as dyslexic individuals who are impaired on explicit learning tasks, such as reading, spelling and writing, are unimpaired on implicit learning tasks. They suggest the existence of two separate systems of learning, each possessing distinct mechanisms.