Specific Learning Disabilities and Emotional-Behavioral Difficulties: Phenotypes and Role of the Cognitive Profile.

Specific Learning Disabilities (SLD) are often associated with emotional-behavioral problems. Many studies highlighted a greater psychopathological risk in SLD, describing both internalizing and externalizing problems. The aims of this study were to investigate the emotional-behavioral phenotype through the Child Behavior Checklist (CBCL), and evaluate the mediating role of background and cognitive characteristics on the relationship between CBCL profile and learning impairment in children and adolescents with SLD. One hundred and twenty-one SLD subjects (7-18 years) were recruited. Cognitive and academic skills were assessed, and parents completed the questionnaire CBCL 6-18. The results showed that about half of the subjects manifested emotional-behavioral problems with a prevalence of internalizing symptoms, such as anxiety and depression, over externalizing ones. Older children showed greater internalizing problems than younger ones. Males have greater externalizing problems compared to females. A mediation model analysis revealed that learning impairment is directly predicted by age and familiarity for neurodevelopmental disorders and indirectly via the mediation of the WISC-IV/WAIS-IV Working Memory Index (WMI) by the CBCL Rule-Breaking Behavior scale. This study stresses the need to combine the learning and neuropsychological assessment with a psychopathological evaluation of children and adolescents with SLD and provides new interpretative insights on the complex interaction between cognitive, learning, and emotional-behavioral phenotypes.

Sleep disturbances in specific learning disorders: a qualitative and quantitative investigation.

BACKGROUND: The literature reports a significant association between sleep disorders and learning disabilities. Nevertheless, not all children with learning disorders have sleep alterations, and which sleep characteristics are associated with which learning difficulty is still unknown. The study aimed at acquiring new information on the relation between sleep disturbances or habits and the learning profiles of children with a specific learning disorder (SLD). METHODS: The Sleep Disturbance Scale for Children (SDSC) and an actigraph (the FitBit-Flex, FB-F) were used in 26 and 16 SLD children respectively; all children were also assessed for learning skills. RESULTS: Although parents' reports at the SDSC did not differentiate SLD from typical readers, the awakening, respiratory and arousal disturbances at the SDSC correlated with sleep duration at the FB-F. Sleep alterations at the FB-F actigraph characterize SLD with literacy difficulties: children with reading decoding difficulties showed shorter minimum amount of sleep than typical children, and severe SLDs showed shorter maximum sleep duration and a higher number of awakenings in comparison to SLDs with mild learning deficits. CONCLUSIONS: Mild alterations in the amount, duration and quality of sleep may characterize children with learning disorders and actigraphy proves to be a useful tool in starting the individual monitoring of sleep in these populations.

Near optimal encoding of numerosity in typical and dyscalculic development.

Dyscalculia is often associated with poor numerosity sensitivity. However, it is not known whether the perceptual systems of dyscalculics have implicit access to the sensory noise of numerosity judgements, and whether their perceptual systems take the noise levels into account in optimizing their perception. We tackled this question by measuring central tendency and serial dependence with a numberline task on dyscalculics and math-typical preadolescents. Numerosity thresholds were also measured with a separate 2AFC discrimination task. Our data confirmed that dyscalculics had poorer numerosity sensitivity and less accurate numberline mapping. Importantly, numberline responses, as well as central tendency and serial dependence strengths, were well predicted by sensory thresholds and could be modelled by a performance-optimizing Bayesian model based on sensory thresholds, suggesting that the functional architecture of systems encoding numerosity in dyscalculia is preserved. We speculate that the numerosity system of dyscalculics has retained those perceptual strategies that are useful to cope with and compensate for low sensory resolution.

Training RAN or reading? A telerehabilitation study on developmental dyslexia.

Rehabilitation procedures recommended for developmental dyslexia (DD) are still not fully defined, and only few studies directly compare different types of training. This study compared a training (Reading Trainer) working on the reading impairment with one (Run the RAN) working on the rapid automatized naming (RAN) impairment, one of the main cognitive deficits associated with DD. Two groups of DD children (N = 45) equivalent for age, sex, full IQ, and reading speed were trained either by Reading Trainer (n = 21) or by Run the RAN (n = 24); both trainings required an intensive home exercise, lasting 3 months. Both trainings showed significant improvements in reading speed and accuracy of passages and words. Bypassing the use of alphanumeric stimuli, but empowering the cognitive processes underlying reading, training RAN may be a valid tool in children with reading difficulties opening new perspectives for children with severe impairments or, even, at risk of reading difficulties.

Typical numerosity adaptation despite selectively impaired number acuity in dyscalculia.

It has been suggested that a core deficit of the "number sense" may underlie dyscalculia. We test this idea by measuring perceptual adaptation and discrimination thresholds for numerosity and object size in a group of dyscalculic and typical preadolescents (N = 71, mean age 12). We confirmed that numerosity discrimination thresholds are higher in developmental dyscalculia, while size thresholds are not affected. However, dyscalculics adapted to numerosity in a similar way to typicals. This suggests that although numerosity thresholds are selectively higher in dyscalculia, the mechanisms for perceiving numerosity are otherwise similar, suggesting that have a similar, but perhaps noisier, number sense.

Telerehabilitation in developmental dyslexia: methods of implementation and expected results.

BACKGROUND: Developmental Dyslexia is a disorder, highly frequent in the school population, for which the recommended rehabilitation procedures are not well defined. This study aimed to automatize reading decoding skills by using an innovative system for rehabilitation, based on a telerehabilitation method. It requires an intensive home-exercise with the supervision, by web, of the clinician. The study had three main aims: to diffuse knowledge on new methods for rehabilitation of reading difficulties; to verify whether an intensive and simplified exercise, targeted to the automation of reading, is suitable for different subgroups of dyslexic children; to define the treatment effects on basic cognitive functions underlying reading. METHODS: Twenty-five children, grouped according to the neuropsychological and anamnestic profiles, took part to the treatment by the software Reading Trainer®. RESULTS: Both speed and accuracy of reading decoding increased significantly after treatment, independently from the functional neuropsychological profile or the history of oral language delay. These changes were specific to decoding and not associated with improvements in reading comprehension or spelling skills. However, there was a "cascade effect" of the treatment efficacy on those basic cognitive functions considered precursors of the ability to read, with significant improvements in rapid lexical access, phonological processing and visual attention. CONCLUSIONS: This study provides information on the efficacy of new tools for telerehabilitation of specific reading disorders.

Spelling Impairments in Italian Dyslexic Children with and without a History of Early Language Delay. Are There Any Differences?

Language delay is considered a frequent antecedent of literacy problems and both may be linked to phonological impairment. However, while several studies have examined the relationship between language delay and reading impairment, relatively few have focused on spelling. In this study, spelling performance of 28 children with developmental dyslexia (DD), 14 children with a history of language delay (LD), and 14 children without (NoLD) and 28 control participants were examined. Spelling was investigated by a writing to dictation task that included orthographically regular stimuli (word and non-words), as well as words with unpredictable transcription. Results indicated that all dyslexic participants underperformed compared to controls on both regular and unpredictable transcription stimuli, but LD performance was generally the worst. Moreover, spelling impairment assumed different characteristics in LD and NoLD children. LD children were more sensitive to acoustic-to-phonological variables, showing relevant failure especially on stimuli containing geminate consonants but also on polysyllabic stimuli and those containing non-continuant consonants. Error analysis confirmed these results, with LD children producing a higher rate of phonological errors respect to NoLD children and controls. Results were coherent with the hypothesis that among dyslexic children, those with previous language delay have more severe spelling deficit, suffering from defective orthographic lexical acquisition together with long-lasting phonological difficulties.

Reading impairment in Duchenne muscular dystrophy: A pilot study to investigate similarities and differences with developmental dyslexia.

Below-average reading performances have been reported in individuals with Duchenne muscular dystrophy (DMD), but literacy problems in these subjects have yet to be characterized. In this study, the presence and characteristics of literacy deficits in boys with DMD were investigated through a comparison with typically developing children and with children affected by developmental dyslexia, with the aim of clarifying whether DMD and developmental dyslexia have overlapping profiles of literacy deficits and whether these deficits are associated, as in children with dyslexia, with impairments in phonological processing and rapid lexical access. The results confirmed the high incidence of literacy problems in boys with DMD and revealed a profile less severe than, but qualitatively similar to, that of Italian children with developmental dyslexia. Both groups showed specific difficulties in reading and writing words and a reduced rapid automatized naming (RAN) speed. This is the first time that a RAN speed deficit has been documented in DMD. Moreover, the boys with DMD and the subgroup of dyslexic children with a previous language delay showed additional deficits in phonological processing. The impairments highlighted in this study could explain the reading difficulties observed in boys with DMD and suggest that there is a need for targeted preschool interventions.

The contribution of discrete-trial naming and visual recognition to rapid automatized naming deficits of dyslexic children with and without a history of language delay.

Children with Developmental Dyslexia (DD) are impaired in Rapid Automatized Naming (RAN) tasks, where subjects are asked to name arrays of high frequency items as quickly as possible. However the reasons why RAN speed discriminates DD from typical readers are not yet fully understood. Our study was aimed to identify some of the cognitive mechanisms underlying RAN-reading relationship by comparing one group of 32 children with DD with an age-matched control group of typical readers on a naming and a visual recognition task both using a discrete-trial methodology, in addition to a serial RAN task, all using the same stimuli (digits and colors). Results showed a significant slowness of DD children in both serial and discrete-trial naming (DN) tasks regardless of type of stimulus, but no difference between the two groups on the discrete-trial recognition task. Significant differences between DD and control participants in the RAN task disappeared when performance in the DN task was partialled out by covariance analysis for colors, but not for digits. The same pattern held in a subgroup of DD subjects with a history of early language delay (LD). By contrast, in a subsample of DD children without LD the RAN deficit was specific for digits and disappeared after slowness in DN was partialled out. Slowness in DN was more evident for LD than for noLD DD children. Overall, our results confirm previous evidence indicating a name-retrieval deficit as a cognitive impairment underlying RAN slowness in DD children. This deficit seems to be more marked in DD children with previous LD. Moreover, additional cognitive deficits specifically associated with serial RAN tasks have to be taken into account when explaining deficient RAN speed of these latter children. We suggest that partially different cognitive dysfunctions underpin superficially similar RAN impairments in different subgroups of DD subjects.

Long-term reading and spelling outcome in Italian adolescents with a history of specific language impairment.

Specific language impairment (SLI) diagnosed in the pre-school years is frequently associated with reading and writing difficulties at school age. The nature of this relationship is unclear, despite the availability of a large number of studies, mostly on English speaking children. Phonological processing deficits have been considered the prominent cause of both difficulties. However recent findings in both children with SLI and in children with reading difficulties are not easily accommodated within a single dimensional model explaining the relationship between oral and written language deficits. Our study focuses on the long-term reading and spelling outcome in relation to preschool oral language skills in a group of Italian adolescents with a documented history of SLI. Sixteen Italian adolescents diagnosed as SLI at our Hospital in the pre-school years and 32 normal controls were submitted to an extensive assessment of oral and written language skills. At a group level SLI adolescents had weak oral and written language skills in almost all tests. Results show that reading difficulties have some features in common with those of Italian developmental dyslexics but also have distinct characteristics, since reading accuracy and written comprehension, usually relatively spared in Italian developmental dyslexics, were impaired in adolescents with SLI. Longitudinal analyses showed that expressive morpho-syntactic and lexical abilities at pre-school age were the oral language skills that best predicted reading and spelling outcomes in adolescents with SLI. However, also children with severe phonological impairment in the absence of other oral language deficits showed later literacy difficulties, although less severe and mainly limited to reading accuracy. Our study supports the notion that there is a complex relationship between oral and written language difficulties which may change at different developmental time points, not captured by a single deficit model, but best conceptualized considering multiple interactions between language skills and literacy abilities.

Reading and spelling disabilities in children with and without a history of early language delay: a neuropsychological and linguistic study.

Language delay is a frequent antecedent of literacy problems, and both may be linked to phonological impairment. Studies on developmental dyslexia have led to contradictory results due to the heterogeneity of the pathological samples. The present study investigated whether Italian children with dyslexia showed selective phonological processing deficits or more widespread linguistic impairment and whether these deficits were associated with previous language delay. We chose 46 children with specific reading deficits and divided them into two groups based on whether they had language delay (LD) or not (NoLD). LD and NoLD children showed similar, severe deficits in reading and spelling decoding, but only LD children showed a moderate impairment in reading comprehension. LD children were more impaired in phonological working memory and phonological fluency, as well as in semantic fluency, grammatical comprehension, and verbal IQ. These findings indicate the presence of a moderate but widespread linguistic deficit (not limited to phonological processing) in a subset of dyslexic children with previous language delay that does not generalize to all children with reading difficulties.

Subtypes of developmental dyslexia in transparent orthographies: a comment on Lachmann and Van Leeuwen (2008).

Lachmann and Van Leeuwen (2008) proposed two diagnostic subtypes of developmental dyslexia in a language with transparent orthography (German). The classification was based on reading time, rather than reading errors, for lists of words and nonwords. The two subtypes were "frequent-word reading impaired" (FWRI) and "nonword reading impaired" (NWRI). Notably, FWRI were very slow in reading high-frequency words but as fast as controls in reading nonwords; ca. one-third of these children showed this "reversed lexicality effect" in a particularly marked fashion (i.e., read nonwords two to three times faster than high-frequency words). Since Italian is a highly transparent language, we applied this classification to 87 third- and sixth-grade dyslexics from various previously published studies. Some children showed a marked lexicality effect, while others showed small or no difference between word and nonword reading speed. However, regardless of stimulus length, grade and presence/absence of a previous language delay, no child showed a marked reversed lexicality effect; more generally, no child could be classified as FWRI. These findings indicate that the search for subtypes of developmental dyslexia in transparent orthographies still constitutes an open question.

Do phonologic and rapid automatized naming deficits differentially affect dyslexic children with and without a history of language delay? A study of Italian dyslexic children.

OBJECTIVE: The study aims to verify whether phonologic and rapid automatized naming (RAN) deficits are present and associated in Italian dyslexic children and whether they differentially affect dyslexics with and without a history of previous language delay (LD). BACKGROUND: According to the phonologic core deficit hypothesis, dyslexia may stem from impairment of the representation and manipulation of phonemes and may be closely associated with oral language deficits. However, deficits in tasks not requiring fine-grained phonologic representations, such as RAN, have also been described in dyslexic children. METHODS: Thirty-seven children were selected on the basis of a reading deficit and were assigned to 2 groups according to whether or not they had a history of early LD as determined retrospectively by parental report. A battery of reading and writing, verbal working memory, metaphonologic, RAN, and visual search tests were administered. RESULTS: RAN deficits were shared by most dyslexics (with and without a history of LD), whereas phonologic deficits were mainly associated with a previous LD. This last condition did not result in a more profound impairment of reading and writing decoding skills. CONCLUSION: In a shallow orthography such as Italian, RAN, not phonologic deficits, may represent the main cognitive marker of developmental dyslexia.

Word length effect in early reading and in developmental dyslexia.

Vocal reaction times were measured in Italian dyslexics and in proficient readers while they read single words. Three groups of control participants (for a total of 79) were tested. All were in the first, second or third grade of elementary school. Nine third graders with a low level of reading ability when assessed by standard reading procedures were also tested. Results indicated that vocal RTs of control participants were faster and less sensitive to word length as a function of age; also, there was a particularly marked change between first and second graders. Dyslexics' vocal RTs and errors were much worse than those of peer control participants and resembled those of first grade controls. It is suggested that normal readers in an orthographically transparent language (Italian) adopt a lexical strategy quite early in their learning. On the contrary, dyslexics seem unable to learn this mode of processing and continue to use a sub-lexical reading procedure.