The phonological system of a specifically language-impaired population

Speech profiles of Spanish-Catalan children with developmental language disorder

Children with developmental language disorders (DLD) are especially characterised by morphosyntactic difficulties. Nevertheless, previous studies have also shown that children with DLD have phonological difficulties. This paper aims to describe the productive and perceptive phonological speech profile of Spanish-Catalan children with DLD at the age of six in order to characterise the underlying nature of their difficulties. Fourteen Spanish-Catalan six-year-old children with DLD and 14 control children without language difficulties who attended the same class were assessed with the screening and discrimination tasks of the A-RE-HA: Análisis del Retraso del Habla (Speech Delay Analysis - Catalan and Spanish version). We analysed the production of words, syllables and phonemes, phoneme discrimination and phonological simplification processes used by these children. The results showed that children with DLD have a lower percentile in correct word structures, syllabic structures and phonemes, and have more difficulty discriminating phonemes. Detailed analyses revealed more difficulties with the most complex word and syllabic templates, and with almost all phonemes. Furthermore, children with DLD applied more phonological simplification processes than the control group. An individual analysis showed that only ten of the children with DLD also had a speech delay (percentile < 25), while four had scores in line with their age. These results show that most of the six-year-old children with DLD maintain speech difficulties, which are mainly phonological and not (or not only) articulatory. Therefore, individual differences with respect to speech delay in DLD must be taken into consideration to better detect these children.

Metacognitive Strategies

This study assessed the effect of metacognitive instruction on the spelling and word reading of Hebrew-speaking children with specific language impairment (SLI). Participants were 67 kindergarteners with SLI in a supported learning context. Children were classified into three spelling instruction groups: (a) metalinguistic instruction (ML), (b) ML that integrates metacognitive strategies (MCML), and (c) a control group. Letter naming, letter sounding, word spelling, and word recognition were assessed at pretest and posttest. Findings from spelling and reading tests as well as interviews indicated that both the ML and MCML groups made statistically significant gains in all measures, whereas the control group did not. However, children with SLI who received training in metacognitive strategies significantly outperformed those who received ML alone in spelling and reading skills. This study provides evidence that children with SLI benefit from applying of metacognitive strategies to spelling practices when acquiring early spelling and reading skills.

Differences in the performance of children with specific language impairment and their typically developing peers on nonverbal cognitive tests: a meta-analysis

PURPOSE

This study used meta-analysis to investigate the difference in nonverbal cognitive test performance of children with specific language impairment (SLI) and their typically developing (TD) peers.

METHOD

The meta-analysis included studies (a) that were published between 1995 and 2012 of children with SLI who were age matched (and not nonverbal cognitive matched) to TD peers and given a norm-referenced nonverbal cognitive test and (b) that reported sufficient data for an effect size analysis. Multilevel modeling was used to examine the performance of children with SLI relative to their typically developing, age-matched peers on nonverbal IQ tests.

RESULTS

Across 138 samples from 131 studies, on average children with SLI scored 0.69 standard deviations below their TD peers on nonverbal cognitive tests after adjusting for the differences in the tests used, the low-boundary cutoff scores, the age of the participants, and whether studies matched the two groups on socioeconomic status.

DISCUSSION

The lower performance of children with SLI relative to TD children on nonverbal IQ tests has theoretical implications for the characterization of SLI and clinical and political implications regarding how nonverbal cognitive tests are used and interpreted for children with this disorder.

Brain mechanisms of acoustic communication in humans and nonhuman primates: An evolutionary perspective

Any account of “what is special about the human brain” (Passingham 2008) must specify the neural basis of our unique ability to produce speech and delineate how these remarkable motor capabilities could have emerged in our hominin ancestors. Clinical data suggest that the basal ganglia provide a platform for the integration of primate-general mechanisms of acoustic communication with the faculty of articulate speech in humans. Furthermore, neurobiological and paleoanthropological data point at a two-stage model of the phylogenetic evolution of this crucial prerequisite of spoken language: (i) monosynaptic refinement of the projections of motor cortex to the brainstem nuclei that steer laryngeal muscles, presumably, as part of a “phylogenetic trend” associated with increasing brain size during hominin evolution; (ii) subsequent vocal-laryngeal elaboration of cortico-basal ganglia circuitries, driven by human-specificFOXP2mutations.;>This concept implies vocal continuity of spoken language evolution at the motor level, elucidating the deep entrenchment of articulate speech into a “nonverbal matrix” (Ingold 1994), which is not accounted for by gestural-origin theories. Moreover, it provides a solution to the question for the adaptive value of the “first word” (Bickerton 2009) since even the earliest and most simple verbal utterances must have increased the versatility of vocal displays afforded by the preceding elaboration of monosynaptic corticobulbar tracts, giving rise to enhanced social cooperation and prestige. At the ontogenetic level, the proposed model assumes age-dependent interactions between the basal ganglia and their cortical targets, similar to vocal learning in some songbirds. In this view, the emergence of articulate speech builds on the “renaissance” of an ancient organizational principle and, hence, may represent an example of “evolutionary tinkering” (Jacob 1977).

Phonological mean length of utterance in specific language impairment: a multi-case study of children acquiring Finnish

This study assesses the phonological development of four Finnish-speaking children (ages 4;8, 4;9, 4;9 and 5;5) with specific language impairment (SLI) and dyspractic features in speech. The analysis is performed using the phonological mean length of utterance (pMLU) method. Moreover, the children's phonological abilities are evaluated qualitatively in relation to segments, phonotactics and word structure. The results are compared with those obtained from four age-matched typically developing peers and with the data from an earlier study using the pMLU method on younger, typically developing Finnish children. In the pMLU analysis, the children with SLI performed roughly at the level of typically developing 2-year-old children. The qualitative analyses revealed that children with SLI had difficulties in producing word-medial clusters and word-initial consonants and that they exhibited frequent consonant assimilations, infrequent errors and vowel errors. The pMLU method did differentiate between children with SLI and typically developing children. However, qualitative analyses revealed some weaknesses of the pMLU method when assessing Finnish children with SLI.

Investigating the effects of syllable complexity in Russian-speaking children with SLI

This study examined the effect of number of syllables and syllable structure on repetition of pseudo-words by Russian-speaking children with Specific Language Impairment (SLI) and typically developing (TD) children. One hundred and forty-four pseudo-words, varying in length and syllable complexity, were presented to two groups of children: 15 children with SLI, age range 4 ; 0 to 8 ; 8, and 15 TD children matched in age to the SLI group. The number of errors in the repetition of pseudo-words was analyzed in terms of the number of syllables and syllable complexity. The results demonstrated that children with SLI have deficits in working memory capacity. In addition to the pseudo-word length, the repetition performance was affected by syllable structure complexity.

Developmental disorders of speech and language: from genes to brain structure and function

Functional and structural brain imaging studies of developmental disorders provide insights into their neural correlates and have potential to bridge the gap between genotype and phenotype. We have used such techniques to investigate the neural correlates of two developmental disorders of speech and language, in which a genetic etiology is either known or strongly suspected. The first disorder is one shared by the affected members of the KE family who have a mutation in the FOXP2 gene. The brain structural and functional correlates of this disorder help clarify the nature of the behavioral impairment. They confirm that a deficit in auditory-motor learning of articulation patterns is core to the behavioral phenotype. In the second disorder, developmental stuttering, brain imaging data reveal functional abnormalities consistent with theories that it is caused by a basal ganglia deficit and structural differences consistent with an impairment in auditory-motor integration necessary for fluent speech. The common finding of basal ganglia abnormality in two developmental disorders of speech and language is discussed.

Phonological Profile of Spanish-Catalan Children with Specific Language Impairment at Age 4: Are There Any Changes over Time?

The phonology of a group of Spanish-Catalan children with specific language impairment (SLI, n = 5), who had been analysed at age 3;10, is now analysed at age 4;09 and compared with two control groups: an age-matched control (n = 5) and a language level control (measured using the mean length of utterance by words; n = 5). The children with SLI continue to show a delay in the acquisition of segments, syllabic structures and in the use of the simplification processes, but not in word structures, compared with their age-matched controls. Children with SLI also display significant differences compared with their language level controls, but not in the same areas as observed at age 3: the differences are now in nasals and liquids at the segmental level, and in CCV, CVC and other complex structures at the syllabic level. There are also some simplification processes that seem to be more prevalent in these children than in their language level controls: absence of trill, cluster reductions and consonant deletions. The results enable us to interpret SLI as more than a delayed development and to show the differences in the profiles over time.

Speech, prosody, and voice characteristics of a mother and daughter with a 7;13 translocation affecting FOXP2

PURPOSE

The primary goal of this case study was to describe the speech, prosody, and voice characteristics of a mother and daughter with a breakpoint in a balanced 7;13 chromosomal translocation that disrupted the transcription gene, FOXP2 (cf. J. B. Tomblin et al., 2005). As with affected members of the widely cited KE family, whose communicative disorders have been associated with a point mutation in the FOXP2 gene, both mother and daughter had cognitive, language, and speech challenges. A 2nd goal of the study was to illustrate in detail, the types of speech, prosody, and voice metrics that can contribute to phenotype sharpening in speech-genetics research.

METHOD

A speech, prosody, and voice assessment protocol was administered twice within a 4-month period. Analyses were aided by comparing profiles from the present speakers (the TB family) with those from 2 groups of adult speakers: 7 speakers with acquired (with one exception) spastic or spastic-flaccid dysarthria and 14 speakers with acquired apraxia of speech.

RESULTS

The descriptive and inferential statistical findings for 13 speech, prosody, and voice variable supported the conclusion that both mother and daughter had spastic dysarthria, an apraxia of speech, and residual developmental distortion errors.

CONCLUSION

These findings are consistent with, but also extend, the reported communicative disorders in affected members of the KE family. A companion article (K. J. Ballard, L. D. Shriberg, J. R. Duffy, & J. B. Tomblin, 2006) reports information from the orofacial and speech motor control measures administered to the same family; reports on neuropsychological and neuroimaging findings are in preparation.

Specific language impairment is not specific to language: the procedural deficit hypothesis

Specific Language Impairment (SLI) has been explained by two broad classes of hypotheses, which posit either a deficit specific to grammar, or a non-linguistic processing impairment. Here we advance an alternative perspective. According to the Procedural Deficit Hypothesis (PDH), SLI can be largely explained by the abnormal development of brain structures that constitute the procedural memory system. This system, which is composed of a network of inter-connected structures rooted in frontal/basal-ganglia circuits, subserves the learning and execution of motor and cognitive skills. Crucially, recent evidence also implicates this system in important aspects of grammar. The PDH posits that a significant proportion of individuals with SLI suffer from abnormalities of this brain network, leading to impairments of the linguistic and non-linguistic functions that depend on it. In contrast, functions such as lexical and declarative memory, which depend on other brain structures, are expected to remain largely spared. Evidence from an in-depth retrospective examination of the literature is presented. It is argued that the data support the predictions of the PDH, and particularly implicate Broca's area within frontal cortex, and the caudate nucleus within the basal ganglia. Finally, broader implications are discussed, and predictions for future research are presented. It is argued that the PDH forms the basis of a novel and potentially productive perspective on SLI.

Genetic and environmental risks for specific language impairment in children

Specific language impairment (SLI) is the term used to refer to unexplained difficulties in language acquisition in children. Over the past decade, there has been rapid growth of evidence indicating that genes play an important part in the aetiology of SLI. However, further progress in elucidating the role of genes in causing SLI is limited by our lack of understanding of the phenotype. Studies to date have been hampered by the fact that we do not know whether SLI should be treated as a discrete disorder or a continuous variable, let alone which measures should be used to identify cases, or how many subtypes there are. Recent research suggests that theoretically motivated measures of underlying processes may be better than conventional clinical diagnoses for identifying aetiologically distinct types of language impairment. There has been a tendency for researchers to embrace parsimony and look for a single cause of SLI-or in any event, to identify different subtypes, each with a different single cause. Research is reviewed that suggests that may not be a fruitful approach to SLI, and that an approach in terms of multiple risk and protective factors, which is widely adopted in medicine, is more realistic.