Which linguistic measures distinguish transient from persistent language problems in Late Talkers from 2 to 4 years? A study on Italian speaking children

BACKGROUND

In spite of the large literature on Late Talkers (LTs) it's still unclear which factors predict outcome in children younger than 3 years old.

AIMS

To identify the early language characteristics of LTs whose outcome was either a transient delay or a Developmental Language Disorder (DLD).

METHODS AND PROCEDURES

50 LTs were assessed both by indirect and direct measures of expressive and receptive language at three time points between 2 and 4 years of age.

OUTCOMES AND RESULTS

At the first evaluation, all LTs had an expressive language delay; 61% also had delayed early syntactic comprehension. Three different linguistic outcomes emerged: children who caught up with their peers ("Late Bloomers") at age 3; children with slow language recovery ("Slow Learners") at age 4 and children at risk of DLD. The linguistic measures that differentiated the groups changed with age. By 28 months, impaired syntactic comprehension differentiated children at risk of DLD at 4 years of age, from the other two groups. By 36 months, the discrepancy between vocabulary size and age was larger in children with persistent language difficulties compared to both "Late Bloomers" and "Slow Learners". Expressive grammar differentiated the groups significantly by age 3 with difficulties in this domain still persisting in children with DLD at age 4.

CONCLUSIONS

An early syntactic comprehension delay was a predictive index of DLD in LTs, suggesting the importance of evaluating this language component when assessing LT toddlers.

IMPLICATIONS

LTs with receptive-expressive language delay around 24-30 months could benefit from an early language intervention.

Cognitive profile in Duchenne muscular dystrophy boys without intellectual disability: The role of executive functions

The aim of our prospective observational study was to assess profiles of cognitive function and a possible impairment of executive functions in a cohort of boys with Duchenne muscular dystrophy without intellectual and behavior disability. Forty Duchenne boys (range of age: 6 years to 11 years and 6 months) were assessed by Wechsler Intelligence scale and battery of tests including tasks assessing working memory and executive functions (inhibition and switching, problem solving and planning). In our cohort some aspects of cognitive function were often impaired. These included multitasking, problem solving, inhibition and working memory necessary to plan and direct goal oriented behavior. Our results support the suggestion that aspects of cognitive function could be impaired even in boys without intellectual disability and support the hypothesis that executive functions may play an important role in specific aspects of cognitive impairment in Duchenne muscular dystrophy.

Acquired focal brain lesions in childhood: effects on development and reorganization of language

In the present paper, we address brain-behaviour relationships in children with acquired aphasia, by reviewing some recent studies on the effects of focal brain lesions on language development. Timing of the lesion, in terms of its occurrence, before or after the onset of speech and language acquisition, may be a major factor determining language outcome. However, it is still unclear which are the effects of aphasia occurring between 2 and 5 years of age, a time window which is crucial for acquiring and automatizing the basic rules of native language. A comprehensive review of the literature on acquired childhood aphasia precedes the description of long-term follow-up (20 years) of two identical twins, one of whom became aphasic at 3 years and 4 months after infarction of the left sylvian artery. Psycholinguistic analysis and fMRI data show a slow and incomplete recovery from non-fluent aphasia associated to an intra-hemispheric organization of language. These data, which support the potential but also the limits of neural plasticity during language development, are discussed in the light of the literature on the time-course and neural bases of acquired childhood aphasia.

Brain representation of phonological processing in Italian: individual variability and behavioural correlates

Neuroimaging literature on phonological processing during reading lacks of studies taking into account orthographic differences across languages and behavioural variability across subjects. The present study aimed at investigating brain representation of phonological processing in reading Italian, a language with regular orthography, with particular regard to inter-individual variability and brain-behavioural correlates. Ten Italian adults performed a rhyme generation and a rhyme judgment task during fMRI acquisition and were tested with behavioural measures of phonological processing. Results for both tasks showed activations of the left Inferior Frontal Gyrus and Dorsolateral Prefrontal Cortex, likely underlying output sublexical strategies, for all or most of the subjects, while a minority of subjects activated the Superior Temporal Sulcus and the Temporo-Parietal-Occipital Junction. These results suggest that phonological processing of written Italian is based on the prevalent use of frontal structures. However, it is of interest that the activation of the Superior Temporal Sulcus, involved in phonological input, was associated to better behavioural performances in tasks of phonological processing. Our findings may contribute to understand neural correlates of phonological processing of languages with regular orthography.

Language organisation in left perinatal stroke

Right-hemispheric organisation of language has been observed following early left-sided brain lesions. The role of the site of damage is still controversial, as other aspects influence the pattern of speech organisation including timing of the lesion and the presence of epilepsy. We studied a group of 10 term-born children homogeneous for timing/type of lesion and clinical picture. All subjects had left perinatal arterial stroke, right hemiplegia, normal cognitive functions and no or easily controlled epileptic seizures. In half the patients, the lesion clearly involved Broca's area, in the other half it was remote from it. Language lateralization was explored by an fMRI covert rhyme generation task. Eight of 10 subjects showed a right lateralisation of language, including all five patients with a damaged left Broca and 3/5 of those without it. Group analysis in patients with right hemispheric organisation showed brain activations homotopic to those found in the left hemisphere of a matched control group. Our findings confirm that, at the end of gestation, the human brain exhibits extraordinary (re-)organisational capabilities. Language organisation in the right hemisphere is favoured by the presence of destructive lesions of the left Broca's area at birth, and occurs in brain regions homotopic to those usually involved in language processing.

A view to regressive autism through home movies. Is early development really normal?

OBJECTIVE

To describe early development of children with regressive autism.

METHOD

Home movies from the first 18 months of life of three groups of children with early onset autism (EOA), regressive autism (RA) and typical development (TD) were rated through the Grid for Attention in Infants in three age ranges. Different ANOVA and post hoc-tests were conducted on frequencies of behaviours.

RESULTS

Differently from TD, for both RA and EOA non-social attention is higher than social attention across ages. While EOA is characterized by an early deficit in social attention, in RA social attention increases until the first birthday when its decrease proceeds at the same rate as the increase of non-social attention.

CONCLUSION

We hypothesize that the intense interest towards objects can be the first sign of an atypical development also in RA; this distinguishing feature lead us to believe that regression, based on the assumption of a previous normal development, is only apparent.

Atypical language lateralization and early linguistic development in children with focal brain lesions

The effects of congenital, unilateral, focal brain lesions on early linguistic development and hemispheric lateralization for language were investigated longitudinally in 24 preschool children with hemiplegia (14 males, 10 females), 12 with left hemisphere damage (LHD) and 12 with right hemisphere damage (RHD). A comprehensive linguistic assessment was performed at 2 and 3 years of life; cerebral lateralization for language was measured by the Fused Dichotic Words Listening Test. An early left-side specificity for language was indicated by the presence of lexical and grammatical delay in most children with LHD. In the dichotic listening test all 12 children with LHD showed a shift of language lateralization from the left to the right hemisphere. Atypical lateralization coefficients (lambda), i.e. values falling more than two standard deviations from the mean of a normative sample, were associated with a delay in lexical and grammatical development, especially after LHD. In addition, cortical-subcortical-periventricular lesions rather than solely periventricular damage, and larger lesions rather than small, were associated with the most atypical lateralization coefficients, irrespective of lesion side. Results of this study suggest that language and lateralization data are closely related and that reallocation of language functions in alternative regions of the brain has a cost in terms of a slow rate of language acquisition.

Course of autism signs in the first year of life

Autism spectrum disorders (ASD) are thought to be present right from birth, even if a minority of children displays a normal course during infancy followed by a regression during the second year of life. However, established criteria are not yet available to differentiate these different courses of ASD, and data coming from different sources have not yet been organized into a clear definition. The aim of this study was to elucidate the time of onset, as well as type, frequency and stability of symptoms during the first year of life in ASD. The behavioral summarized evaluation scale, applied to 40 home movies of children later diagnosed as having ASD, showed that most of the subjects (87.5%) display symptoms within the first year of life, when only a small group (12.5%) is completely symptom free. A group of more rated symptoms was found, constituting a typical pattern characterized by being withdrawn, and displaying poor social initiative, hypoactivity, and lack of emotional modulation. The importance of these findings is discussed in relation to early diagnosis and treatment.