Chromosome studies of children with specific speech and language delay

The N400 component in parents of children with specific language impairment

Children with specific language impairment (SLI) often have a family history of language disorder. In this study, ERPs in response to a visual semantic priming task were recorded in parents of children with SLI. Despite equal performance, the ERPs displayed differences in language processing: larger N400 amplitudes indicated that the parents, especially the fathers, were less primed by the preceding context. Difference waveforms showed that the fathers of SLI children, contrary to controls, had less differentiated responses to congruent versus incongruent sentences. We propose that the N400 observations may be residual markers of past language deficiencies in the fathers. No differences in the N400 effect were found in the mothers of SLI children.

[Developmental dysphasia]

Developmental dysphasia is characterized by severe, specific and unexplained developmental language impairment. Phonologic and syntactic disorders of expressive language and perceptual deficit are almost always present. Moreover, certain specific linguistic symptoms are particular to each dysphasic child, explaining the efforts to classify different forms of dysphasia. The most important point is to separate receptive dysphasia from the expressive on the one hand, and severe forms from the mild which are closed to "simple language delay", on the other. The evolution of oral language is variable, but often long and difficult, with persistent linguistic deficit. Reading and writing acquisition is usually difficult, although very important for the socio-professional outcome and language improvement. The etiology remains unknown and is probably multifactorial. One pathogenic hypothesis is based on the absence of the usual hemisphere specialisation related to various prenatal or postnatal events. A genetic basis seems likely for certain dysphasic children. Development of knowledge about this condition and improvement of both speech therapy and teaching are essential for the outcome of these otherwise intelligent and normal children.

Communicative disorders. The first year of life

Disorders of communication have high incidence and prevalence in the fetus, neonate, and infant, and optimal care is dependent on early recognition and intervention. This article reviews receptive disorders, expressive disorders, and their diagnoses.

Causes and associations of severe and persistent specific speech and language disorders in children

Eighty-two school-age children with severe and persistent specific speech and language disorders were studied. 71 had specific developmental language disorders, three had structural malformations (cleft palate) and eight had disorders acquired after a period of normal language development, including five with Landau-Kleffner syndrome. The sex ratio was 3.8 boys to one girl. Nearly half had a family history of speech-language disorder, with one in 5.2 affected siblings. Aetiological factors were found in 26 per cent: 11 per cent prenatal, 3 per cent perinatal and 12 per cent postnatal. 21 per cent had had a seizure and 7 per cent had had seizures after the age of eight. 29 per cent were left-handed, 90 per cent were clumsy and 22 per cent first walked after 18 months. The complex origins of specific speech and language disorders are discussed.

Hormonal influences in developmental learning disabilities

Developmental language and learning disabilities in children can take many different forms and can result from a variety of causes. Research to date has focused primarily on specific disabilities in learning, which are characterized by a significant delay or disorder in one aspect of learning against a background of otherwise normal development. Learning disabilities affecting language and/or reading acquisition (developmental dysphasia and dyslexia) have been studied most thoroughly. Verbal learning disabilities occur more frequently in boys than in girls, and there is a higher than expected incidence of left-handedness among affected children. Although there are many reasons why a child may have delayed or disordered language development, differential diagnosis of specific developmental language or reading disorders calls for ruling out mental retardation, peripheral auditory or visual dysfunction, autism, frank neurological impairments such as hemiplegia or seizure disorder, and severe social deprivation or lack of educational opportunity. The typical profile of a developmentally dysphasic or dyslexic child is one who shows a marked discrepancy between nonverbal (performance) IQ and verbal IQ, with a history of delayed or disordered speech, language and/or reading development. Such a child usually performs quite normally on visual spatial tasks, while demonstrating severe deficits in tasks of auditory temporal processing, motor sequencing, phonological processing and memory, language, reading and spelling. This characteristic neuropsychological profile may suggest left hemisphere dysfunction or a failure to develop normal cerebral lateralization. The etiology of these developmental learning disorders is unknown, but there is evidence of familial aggregation, indicating a potential genetic basis. Although these children respond to remediation, longitudinal studies have shown that the symptoms often persist into adulthood (see Tallal, 1988, for a more detailed discussion).

Unexpected sex-ratios in families of language/learning-impaired children

There is a well-documented propensity of males affected with developmental language/learning impairment. Results from this study demonstrate, unexpectedly, that this sex-ratio difference of males to females with developmental language/learning disorders was found to occur significantly only in families with a language/learning-impaired mother. In addition, a remarkably aberrant offspring sex-ratio was found in families of language/learning-impaired children who had an affected mother, but not father. Mothers who were developmentally language/learning-impaired had three times as many sons as daughters, and five times as many language/learning-impaired sons as daughters. Genetic and hormonal influences that might affect both sex-ratio and neuroanatomical development and disorders are discussed.