The causes of specific developmental language disorder ("development dysphasia")

The Value of Electroencephalogram in Assessing Children With Speech and Language Impairments

Purpose We sought to estimate the prevalence of isolated epileptiform activity (IEA) in children with speech and language impairments and discuss the utility of an electroencephalogram (EEG) in assessing these children. Method We conducted a systematic review and searched for eligible studies in 8 databases. All languages were included, and meta-analyses were performed. Results We found 55 prevalence estimates (8 with control group). The odds of having IEA were 6 times greater for children with speech and language impairments than for typically developing children. The overall pooled prevalence of IEA was 27.3%. A wide variation between the prevalence estimates was, to a certain degree, explained by type of impairment (8.1% in speech impairments, 25.8% in language impairments, and 51.5% in language regression). Sleep EEGs detected a significantly higher prevalence than awake EEGs. Although the presence of epilepsy gave a significantly higher prevalence than if epilepsy was not present, 33.5% of children with language impairment but without epilepsy were found to have IEA in sleep EEGs. Conclusions This systematic review shows that IEA is 6 times more prevalent in children with speech and language impairment than in typically developing children. However, the prevalence rates vary to a great extent. Uncovering IEA will, in addition to information from other clinical assessments, provide a more comprehensive understanding of the child's impairments. We argue that, although EEG is of questionable value when assessing children with speech impairments, sleep EEG could be valuable when assessing children with language impairments and, in particular, children who experience language regression.

Efficacy of auditory training using the Programa de Escuta no Ruído (PER) software in students with auditory processing disorders and poor school performance

PURPOSE

Investigate the efficacy of auditory training in students with auditory processing disorders and poor school performance using the software Programa de Escuta no Ruído (PER), which addresses auditory processing skills, specifically listening in noise.

METHODS

Eighteen children aged 8-10 years, of both genders, participated in this study. All individuals participated in the following stages: pre-intervention assessment, intervention (consisting of placebo training, re-evaluation of auditory processing, and auditory training), and post-intervention assessment, so that the same individual is self-control.

RESULTS

No statistically significant difference was observed between the pre-intervention assessment and the post-training auditory processing re-evaluation of the placebo, but statistically significant difference was found between the pre- and post-auditory training conditions.

CONCLUSION

The present study achieved its general objective. The PER software proved to be effective for the auditory training of students with auditory processing disorders and poor school performance.

Comorbidity of motor and language impairments in preschool children of Taiwan

Comorbidity of motor and speech/language impairments was investigated in 363 preschool children between the ages of 5 and 6 years (boys: 205, age 6.04+/-0.48 years; girls: 158, age 5.98+/-0.53 years). The children were sampled from two municipals of Taiwan, and were determined to present no apparent neurological, musculoskeletal, cardiopulmonary system impairment or mental insufficiency. They were administered with three speech/language tests and a motor test (Movement Assessment Battery for Children, or M-ABC). The results showed a significant correlation between the total score of the motor test and the total score of each of the speech and language tests. Regression analysis that controlled for IQ (C-TONI) further showed that manual dexterity, but not ball skills or balance, of M-ABC was predictive of all scores on the speech and language tests. To determine a deficit on a test, a score at or below the 10th percentile of the norm or a score at or below 1.25SD from the group mean was established as the cutoff. For the speech/language impairment, a deficit on at least two out of the three tests also applied. Following these criteria, 22 children (6.1%) were identified to have Developmental Speech and Language Disorder (DSLD), and 45 (12.4%) to have Developmental Coordination Disorder (DCD). Comorbid DSLD and DCD were found in six children (1.65%). Chi-square analysis revealed a significant correlation between DSLD and DCD (p<.03). The odds of DSLD was higher (by about three-fold) among the children with DCD than among the children without (0.15 vs. 0.05). Comorbid motor and speech/language impairments in preschool children appear to be a significant clinical condition that requires the attention of the therapeutic community. Manual dexterity, in particular, seems to be an important clue for understanding the shared mechanism of motor and speech/language impairments.

Language and motor speech skills in children with cerebral palsy

The aim of the study was to investigate associations between the severity of motor limitations, cognitive difficulties, language and motor speech problems in children with cerebral palsy. Also, the predictive power of neonatal cranial ultrasound findings on later outcome was investigated. For this purpose, 36 children (age range 1 year 10 months to 9 years 0 months) with cerebral palsy due to premature birth and white-matter damage (periventricular leukomalacia) participated in the study. Twenty-two children (62%) had an intelligence level above 70. One-half of this group exhibited motor speech problems. Children with an intelligence level below 70 (n=14, 38%) showed problems in motor speech skills as well as in verbal expressive and comprehensive skills. Neonatal cranial ultrasonography findings were moderately associated with the severity of functional motor limitations.

LEARNING OUTCOMES

Readers will be able to: (1) describe different hypotheses regarding the relationship between language, speech, intelligence level and severity of cerebral palsy, (2) discuss how intelligence and functional motor limitations impact language and speech performance for children with cerebral palsy and (3) discuss the predictability of the ultrasound methodology.

Highly significant linkage to the SLI1 locus in an expanded sample of individuals affected by specific language impairment

Specific language impairment (SLI) is defined as an unexplained failure to acquire normal language skills despite adequate intelligence and opportunity. We have reported elsewhere a full-genome scan in 98 nuclear families affected by this disorder, with the use of three quantitative traits of language ability (the expressive and receptive tests of the Clinical Evaluation of Language Fundamentals and a test of nonsense word repetition). This screen implicated two quantitative trait loci, one on chromosome 16q (SLI1) and a second on chromosome 19q (SLI2). However, a second independent genome screen performed by another group, with the use of parametric linkage analyses in extended pedigrees, found little evidence for the involvement of either of these regions in SLI. To investigate these loci further, we have collected a second sample, consisting of 86 families (367 individuals, 174 independent sib pairs), all with probands whose language skills are >/=1.5 SD below the mean for their age. Haseman-Elston linkage analysis resulted in a maximum LOD score (MLS) of 2.84 on chromosome 16 and an MLS of 2.31 on chromosome 19, both of which represent significant linkage at the 2% level. Amalgamation of the wave 2 sample with the cohort used for the genome screen generated a total of 184 families (840 individuals, 393 independent sib pairs). Analysis of linkage within this pooled group strengthened the evidence for linkage at SLI1 and yielded a highly significant LOD score (MLS = 7.46, interval empirical P<.0004). Furthermore, linkage at the same locus was also demonstrated to three reading-related measures (basic reading [MLS = 1.49], spelling [MLS = 2.67], and reading comprehension [MLS = 1.99] subtests of the Wechsler Objectives Reading Dimensions).

Differences in language performance in variations of lateralization

Language proficiency was studied in 489 primary-school-aged children classified as extreme left-, extreme right-, mild left-, and mild right-handers on the basis of both hand-preference and hand-skill, using a test battery of seven measures. An ANOVA run on factor scores showed neither significant association of language proficiency with variations of lateralization regarding hand-preference and hand-skill nor differences in factor structure derived from a principal component analysis between extreme vs. mild hand-preference and hand-skill groups. Moreover, low language proficiency was not significantly associated with specific patterns of lateralization in hand-preference subgroups. In contrast, low language performers with poor hand-skill were significantly overrepresented both in the extreme left-handed group alone and when combined with the extreme right-handed, in comparison to mild left- and mild right-handed with respect to population. The data are not consistently accommodated by the theory of balanced polymorphism (mainly Annett, 1978, 1985 Annett & Manning, 1989 ). Alternately, factors such as lag of maturation ( Bishop, 1980, 1984, 1990a, 1990b ), delay of growth ( Geschwind & Galaburda, 1985b ), and developmental instability associated with unique patterns of variations in lateralization ( Yeo, Gangestad, & Daniel, 1993 ) are discussed as possible factors accounting for the present results.

Do the hands talk on mind's behalf? Differences in language ability between left- and right-handed children

Two hundred seventy children of school age, 135 of whom were left-handed and an equivalent number of whom were right-handed, have been examined in the present study using a test battery of nine language ability measures: Vocabulary, Similarities, Comprehension (WISC-R), Deductive Reasoning, Inductive Reasoning, Sentence Completion, Comprehension of Sentential Semantics, Comprehension of Syntax, and Text Processing. The data analysis has indicated that: (1) One-factor solution applies both to the right- and left-handed population according to Standard Error Scree Method (Zoski & Jurs, 1996) with regard to language ability measures. (2) Handedness discriminates between right-handers (superior) and left-handers (inferior) in language ability. (3) There have been subgroups of left-handed children who differ in language ability distribution compared with right-handed children according to Hierarchical Cluster Analysis. (4) Extreme versus mild bias to hand preference and hand skill do not differentiate performance subgroups neither within the left-handed nor within the right-handed main group. (5) Sex and familial sinistrality do not affect performance. The results are discussed in relation to (a) "human balanced polymorphism" theory advocated by Annett (mainly Annett, 1985, 1993a; Annett & Manning, 1989), (b) potential pathology (mainly Bishop, 1984, 1990a; Coren & Halpern, 1991; Satz, Orsini, Saslow & Henry, 1985) and "developmental instability" (Yeo, Gangestad & Daniel, 1993), and delay of left-hemisphere maturation in left-handed individuals (Geschwind & Galaburda, 1985a,b, 1987), by pointing out the strength and weaknesses of these theoretical approaches in accounting for the present data.

Voice, speech and language characteristics of children with Prader-Willi syndrome

Eleven individuals with Prader-Willi syndrome (PWS), aged between 4 and 25 years, were compared with II non-PWS children of the same sex, age, body mass index and IQ level. Voice, speech and language skills were generally impaired in subjects with PWS. Oral motor function, pitch level and resonance were specifically disordered and clearly differentiated the two groups from each other. Certain biological perinatal factors separated subjects with PWS from other obese children and adolescents, but did not differentiate within the group with PWS and could not account for the speech/language problems. Underlying cerebral dysfunction, combined with a characteristic anatomy of the mouth and larynx in PWS, contributes to altered voice, speech and language function.

A theory of neurolinguistic development

This article offers a developmental theory of language and the neural systems that lead to and subserve linguistic capabilities. Early perceptual experience and discontinuities in linguistic development suggest that language develops in four phases that occur in a fixed, interdependent sequence. In each phase of language, a unique ontogenetic function is accomplished. These functions have proprietary neural systems that vary in their degree of specialization. Of particular interest is an analytical mechanism that is responsible for linguistic grammar. This mechanism is time-locked and can only be turned on in the third phase. Confirming evidence is provided by children who are delayed in the second phase of the language learning process. These children store insufficient lexical material to activate their analytic mechanism. Inactivation behaves like damage, shifting language functions to homologous mechanisms in the nondominant hemisphere, thereby increasing functional and anatomical symmetry across the hemispheres. This atypical assembly of neurolinguistic resources produces functional but imperfect command of spoken language and may complicate learning of written language. The theory thus offers a different role for genetics and early experience, and a different interpretation of neuroanatomic findings, from those entertained in most other proposals on developmental language disorders.

Neuropsychological and neuroimaging findings of developmental dysphasia: A longitudinal case study

This article presents an unusual and interesting neuropsychological and neuroimaging longitudinal study of a child who showed a relatively specific developmental language disorder in the absence of any other significant cognitive, emotional or neurological disturbance. The neuropsychological assessment included tests of intelligence, memory, language and frontal lobe functions. Our patient had a marked developmental language disorder characterized by severe impairment of oral and written language and a restricted vocabulary, even though the comprehension of both spoken and written language was relatively preserved. Moreover, his non-verbal intellectual ability was normal and he showed superior visuoconstructive and visuospatial abilities which suggested good development of right temporoparietal functions. On computerized tomography and magnetic resonance imaging there were no structural abnormalities in those cerebral areas concerned with language, although both neuroimaging studies did show a feasible reversed asymmetry or further atrophy on the left sylvian. It is noticeable that at age 17 a severe deficit in the expressive aspects of language remains. In contrast, visuo-constructive functions have improved. These results suggest a functional reorganization of the brain by increasing non-verbal capabilities. The prognosis in dysphasic syndromes is worse than in acquired aphasia in children, since despite speech therapy, an important language impairment persists during adulthood.

Study of unilateral hemisphere performance in children with developmental dysphasia

Hemisphere specialization for language was studied in 10 children with expressive developmental dysphasia (DD) (mean age 10 years 4 months) submitted to a dichotic listening task (in a word free-recall task and forced-attention task) and a finger tapping/vocalization dual-task paradigm. A nonsense shape dichaptic task was also introduced to control right hemispheric processing. Performances of dysphasic children were compared to those obtained from 15 normal children. The results showed that controls had a right ear advantage in free-recall (words) dichotic listening task and a significant right ear advantage in forced-right-attention task, with a change in ear asymmetry as a consequence of instruction. In the dysphasic group we observed a significant right ear advantage in the free-recall dichotic listening task and no change in ear asymmetry during forced right or forced left condition. Results in time sharing paradigm and nonsense dichaptic task are more difficult to interpret, because there was no interaction between group and condition. These results cannot support a complete left hemisphere dysfunction in developmental dysphasia.

Genetic basis of specific language impairment: evidence from a twin study

Concordance rates were compared for 63 monozygotic (MZ) and 27 dizygotic (DZ) same-sex twin pairs, aged seven years and over, selected because at least one twin met diagnostic criteria for specific speech or language impairment. There was significant heritability for developmental speech and language disorder, defined according to DSM-II-R criteria. When the definition of the phenotype was broadened to include those with a past history of disorder and those with a less pronounced discrepancy between verbal and non-verbal ability, concordance for MZ twins was close to 100 per cent, and that for DZ twins approximately 50 per cent. There was also close similarity between concordant twins for type of disorder. There is good evidence that genetic factors play a role in the aetiology of speech and language impairment; twin data may help us arrive at a clearer conception of the phenotype as well as quantifying the extent of the genetic contribution.

Gradual emergence of developmental language disorders

This article presents a theory of normal and delayed development of language. According to the theory, linguistic capacity develops in critically timed phases that occur gradually and sequentially. Normally, the rapid accumulation of stored utterances activates analytical mechanisms that are needed for the development of linguistic grammar. Children with slowly developing brains have delays in the socially cognitive systems that store utterances, and a critical period for activation of experience-dependent grammatical mechanisms declines without optimal result. Continuing efforts to speak induct species-atypical allocations of neural resources into linguistic service. It is speculated that this compensatory activity leads to compensatory growth, which may ultimately be revealed as volumetric symmetry of perisylvian areas. Because rate of brain maturation is under genetic as well as environmental control, the stage is thus set for an impairment that will seem to be specific and a brain that will appear to be abnormal.

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.

An extended family with a dominantly inherited speech disorder

A three-generation family is described in which 16 members have a severe developmental verbal dyspraxia. Inheritance is autosomal dominant, with full penetrance. Intelligence and hearing are normal.

Specific language impairment as a maturational lag: evidence from longitudinal data on language and motor development

Longitudinal language-test data on 87 language-impaired children assessed at the ages of four, 4 1/2 and 5 1/2 years were converted to age-equivalent scores to compare the rates of development of children who recover from early language delay with those who have more persisting problems. On most measures, over the 18-month period all the children progressed by about 18 months. Thus although children with good and poor outcomes were distinguished in terms of initial level of performance, they did not differ in rate of progress. Speed on a peg-moving task was closely related to language performance. Children who had a good outcome after early language delay had significantly impaired scores at four years, but subsequently were indistinguishable from a control group. Quantitative but not qualitative differences in peg-moving performance were found for children with good and poor outcomes. No association was found between presumptive aetiological factors and language or pegboard performance. These findings are interpreted in terms of a theory which attributes specific language impairment to a maturational lag in neurological development.