Learning-impaired Children Research Articles

The role of naps in memory and executive functioning in early childhood.

While sleep, including naps, has been shown to benefit many cognitive functions in adults, understanding whether naps are beneficial in early childhood has important translational implications. Here we review recent studies which, collectively, suggest that naps indeed benefit cognition at this age. Specifically, declarative, motor, and emotional memory are better if a nap follows learning. Executive functions such as attention and emotion processing are likewise better following sleep. However, a better understanding of the mechanism supporting these benefits and the generalizability to other forms of learning and executive functions is necessary. It is important for future research to extend such findings, which may promote the use of naps to support early education, particularly for learning-impaired children.

Templates for speech-evoked auditory brainstem response performance in cochlear implantees

Introduction Speech-evoked auditory brainstem response (ABR) has been used to assess the fidelity of encoding speech stimuli at the subcortical level in normal individuals in noise and in special populations such as learning-impaired children and musicians. The neural code generated by cochlear implants (CIs) in the auditory brainstem pathway and its similarity to stimulus may account for variable speech development in cochlear implantees. Objective The aim of this study was to describe speech ABR recorded in CI individuals and establish measurement parameters for the neural response and its reproducibility. Participants and methods Children between 5 and 10 years of age implanted in the right ear with fully inserted 12-electrode CIs were selected. All participants had normal morphology of the cochlea and auditory nerve in preoperative computed tomographic scan and MRI. Speech syllable 40 ms /da/ was used to elicit speech ABR. Response traces for intensity input/output functions were harvested. Grand averages were constructed for peak picking. Individual patient responses were analyzed for reproducibility, latency of wave V, root mean square amplitude of the response, and correlation to the stimulus. Results Grand averages showed wave V, followed by the frequency following response. Wave V is a vertex-positive peak, equivalent to that elicited by a click, which reflects the stimulation by the transient /d/. The mean latency of wave V was 2.59±0.7 ms at 70 dBHL. The frequency following response showed multiple sequenced troughs corresponding to the sustained vowel /a/. Individual responses collected for similar stimulus parameters showed high reproducibility, being 99.65% at 60 dBHL and 52.8% at 30 dBHL. Participants showed variable latency and root mean square amplitude-intensity input–output functions slopes. The mean stimulus-to-response correlation was 18.1±3.1%. Conclusion Speech ABR in CI participants shows similar morphology to that recorded in norms. CIs thus transcribe the speech signal with high fidelity to the brainstem pathways.

Distribution of Binocular Vision Anomalies and Refractive Errors in Iranian Children With Learning Disabilities

Background: Visual problems in children contribute to learning disorders, which are one of the most influential factors in learning. Objectives: The aim of the present study was to determine the prevalence of refractive and binocular vision errors in children with learning disorders. Patients and Methods: In this cross-sectional study, 406 children with learning disorders with a mean age of 8.56 ± 2.4 years were evaluated. Examinations included the determination of refractive errors with an auto-refractometer and static retinoscopy, measurement of visual acuity with a Snellen chart, evaluation of ocular deviation, and measurement of stereopsis, amplitude of accommodation, and near point of convergence. Results: Of the 406 participants, 319 (78.6%) were emmetropic in the right eye, 14.5% had myopia, and 6.9% had hyperopia according to cycloplegic refraction. Astigmatism was detected in 75 (18.5%) children. In our study, 89.9% of the children had no deviation, 1.0% had esophoria, and 6.4% had exophoria . In addition, 2.2% of the children had suppression. The near point of convergence ranged from 3 to 18 cm, with a mean of 10.12 ± 3.274 cm. Moreover, 98.5 and 98.0% of the participants achieved complete vision with the best correction in the right and left eye, respectively. The best corrected visual acuity in the right and left eye was achieved in 98.5 and 98.0% of the children, respectively. Conclusions: The pattern of visual impairment in learning-impaired children is not much different from that in normal children; however, because these children may not be able to express themselves clearly, lack of correct diagnosis and appropriate treatment has resulted in a marked defect in recognizing visual disorders in these children. Therefore, gaining knowledge of the prevalence of refractive errors in children with learning disorders can be considered the first step in their treatment.

Contribution of Resolved and Unresolved Harmonic Regions to Brainstem Speech-Evoked Responses in Quiet and in Background Noise.

Speech auditory brainstem responses (speech ABR) reflect activity that is phase-locked to the harmonics of the fundamental frequency (F0) up to at least the first formant (F1). Recent evidence suggests that responses at F0 in the presence of noise are more robust than responses at F1, and are also dissociated in some learning-impaired children. Peripheral auditory processing can be broadly divided into resolved and unresolved harmonic regions. This study investigates the contribution of these two regions to the speech ABR, and their susceptibility to noise. We recorded, in quiet and in background white noise, evoked responses in twelve normal hearing adults in response to three variants of a synthetic vowel: i) Allformants, which contains all first three formants, ii) F1Only, which is dominated by resolved harmonics, and iii) F2&F3Only, which is dominated by unresolved harmonics. There were no statistically significant differences in the response at F0 due to the three variants of the stimulus in quiet, nor did the noise affect this response with the Allformants and F1Only variants. On the other hand, the response at F0 with the F2&F3Only variant was significantly weaker in noise than with the two other variants (p<0.001). With the response at F1, there was no difference with the Allformants and F1Only variants in quiet, but was expectedly weaker with the F2&F3Only variant (p<0.01). The addition of noise significantly weakened the response at F1 with the F1Only variant (p<0.05), but this weakening only tended towards significance with the Allformants variant (p=0.07). The results of this study indicate that resolved and unresolved harmonics are processed in different but interacting pathways that converge in the upper brainstem. The results also support earlier work on the differential susceptibility of responses at F0 and F1 to added noise.

Principles for School-Age Language Intervention: Insights from a Randomized Controlled Trial

Principles for School-Age Language Intervention: Insights from a Randomized Controlled Trial

Brain Stem Response to Speech: A Biological Marker of Auditory Processing

The auditory brain stem response to speech mimics the acoustic characteristics of the speech signal with remarkable fidelity. This makes it possible to derive from it considerable theoretical and clinically applicable information relevant to auditory processing of complex stimuli. Years of research have led to the current characterization of these neural events with respect to the underlying acoustic information they reflect. The majority of data reviewed here originates from studies using a /da/ syllable to elicit the brain stem response, which consists of transient and periodic (frequency following) neural activity. We describe how the human auditory brain stem response separately encodes source and filter characteristics of the acoustic signal, which reflects paralinguistic and linguistic information simultaneously conveyed in speech. In normal-hearing individuals, these two classes of response components (source and filter) are highly correlated within a class but not between classes. This response dissociation becomes pronounced when stimuli are presented in background noise or with faster stimulus rates. In addition, some learning-impaired children show a selective deficiency in the neural encoding of acoustic features associated with the filter characteristics of speech. These children show no deficits in the encoding of source components, further supporting the notion of separate neural mechanisms. Overall, the auditory brain stem response to speech provides a way to access subcortical auditory processing mechanisms and may be used as a biological marker of deficient sound encoding associated with learning and auditory processing disorders.

Information Transmission Defect Identified and Localized in Language Learning Impaired Children by Means of Electrophysiology

Children with language processing deficits have various learning impairments and poor scholastic performance. In 3-10% of all children a specific language processing deficit can be identified by the Sound Connecting Sub-Test of the Illinois Test of Psycholinguistic-Abilities (SC-ITPA). These children among which we drew our index group (AS-Group) suffer from the disability to recognize isolated sounds as parts of words. Following linguistic terminology this is known as an auditory sequential sound processing deficit (ASSPD) Eighteen children (AS-Group) and 21 controls (C-Group) were subjected to mapped P300 evoked potential analyses of cortical response to acoustic stimulation in the oddball paradigm. The data presented here show that there exists significant relation between the P300 amplitude reduction and ASSPD. The P300 amplitude decrease measured in the AS-Group is due to a reduced information transmission in accordance with Johnson's Triarchic Model of the P300 Amplitude. The cerebral structures involved in poor language processing are localized at the left temporo-parietal cortex. This supports the hypothesis that the underlying neuronal defect of ASSPD is localized in the language center and not in the auditory pathway. The P300 amplitude may serve as electrophysiological tool to identify ASSPD and to quantify the degree of improvement in the course of specific therapy.

Neural plasticity following auditory training in children with learning problems

This study examined the plasticity of the central auditory pathway and accompanying cognitive changes in children with learning problems. Children diagnosed with a learning disability and/or attention deficit disorder worked with commercial auditory processing training software for 8 weeks; control groups consisted of normal-learning and learning-impaired children who did not participate in any remedial programs. Auditory brainstem function was evaluated in response to click and speech stimuli in quiet; cortical responses to speech stimuli were obtained in quiet and noise. Academic achievement and cognitive abilities were assessed with standardized measures. Compared to controls, the trained group improved on measures of auditory processing and exhibited changes in cortical responses in quiet and in noise. In quiet, cortical responses reflected an accelerated maturational pattern; in background noise, cortical responses became more resistant to degradation. Brainstem responses did not change with training. Children with learning problems who practiced with auditory training software exhibited plasticity of neural encoding of speech sounds at the cortical, but not subcortical, level of the auditory pathway. This plasticity was accompanied by improvement in behavioral performance. This study demonstrates that in learning-impaired children working with commercial auditory processing training programs affects both the perception and the cortical representation of sound.

Neural representation and perception of speech sounds in children with learning problems

An inability to process auditory information, especially speech, characterizes many children with learning and attention problems. These speech–sound perception problems may arise, at least in some cases, from faulty representation of the speech signal in central auditory centers. Our working hypothesis is that acoustic–phonetic disorders are abnormalities in preconscious neurophysiologic representation of sound structure by central auditory pathway neurons and is reflected by subcortical and cortical aggregate neural responses. Brainstem and cortical potentials (ABR, FFR, cortical P1/N1/N2, MMN) reflect activity from different anatomic sources and represent different aspects of auditory function. An obvious characteristic distinguishing these responses is their development time course. Results indicate that while normal and learning impaired children do not differ in auditory system development per se, they develop different listening strategies which affect the neural representation of sound structure along the auditory pathway. [Work supported by NIH RO1 DC 01510.]

Speech modifications algorithms used for training language learning-impaired children.

In this paper, the details of processing algorithms used in a training program with language learning-impaired children (LLI's) are described. The training program utilized computer games, speech/language training exercises, books-on-tape and educational CD-ROM's. Speech tracks in these materials were processed using these algorithms. During a four week training period, recognition of both processed and normal speech in these children continually increased to near age-appropriate levels. We conclude that this form of processed speech is subject to profound perceptual learning effects and exhibits widespread generalization to normal speech. This form of learning and generalization contributes to the rehabilitation of temporal processing deficits and language comprehension in this subject population.

Oral health condition of 12-year-old handicapped children in Flanders (Belgium).

The dental condition of 626 12-year-old handicapped children with mild mental or moderate to severe mental retardation or learning impairment, being 25% of the population of each of these groups, was examined in Flanders. An evaluation of oral cleanliness showed poor oral hygiene in 31.8% of the children. No significant differences were found in oral cleanliness among types of handicapping conditions. The mean DMFT score was 2.9 (s: 2.6) and DMFS score was 5.4 (s: 5.6). Almost 21% of the children were free of caries or fillings. No significant differences were found among groups of handicapped children. Handicapped children presented a low level of restorative care (restorative index score: 48.7%). Mildly mentally retarded children demonstrated the lowest restorative index (43.9%). The caries experience of first permanent molars represented the largest part of the DMFT score (64.1%). Sealants were present in 7.9% of children examined. A considerable percentage of mildly mentally retarded children and learning impaired children did not brush daily (22.1% and 20.9%) and did not receive help with toothbrushing from their parents or carers (91.0% and 94.7%, respectively).

Language, Learning, and Behavioral Disturbances in Childhood: A Longitudinal Perspective

Objective Investigate longitudinally the course of development of preschool learning impaired (LI) children to better understand the interaction between neurodevelopmental delay, behavioral/emotional disorders, and language development and disorders. Method Relationships between developmental language disorders and emotional problems were investigated in 99 8-year-old specifically language impaired and control children originally assessed at age 4 years using the Achenbach Child Behavior Checklist and the Conners' Parents Questionnaire. Results LI children received higher behavior problem scores and were more likely to score in the clinical range than were control children. Neither degree of early language impairment nor amount of language improvement predicted 8-year behavioral/emotional status. LI children with the largest drop in IQ between ages 4 and 8 received the highest behavior problem scores. No significant comorbid relationship was seen between LI and attention-deficit hyperactivity disorder. Conclusions The enhanced incidence of behavior problems reported heretofore may be related more to lower IQ than to linguistic deficit per se. Care must be taken to differentiate the symptoms of neurodevelopmental delay and emotional disturbance, however, preschool children with scores in the clinical range on such measures should be referred for additional evaluation. J. Am. Acad. Child Adolesc. Psychiatry, 1993, 32, 3:585–594.

Effect of sleep deprivation on the EEG of learning-impaired children with absence seizures.

Learning-impaired children can present with a clinical history suggesting additional problems, including attention deficit disorder and absence seizures. Physicians use clinical judgment in diagnosing the former, but rely heavily on the electroencephalogram (EEG) to diagnose the latter. Most clinicians are reluctant to treat patients with anticonvulsants without seeing 3 Hz spike-and-wave discharges in an EEG. We studied 21 learning-impaired and 7 control children, ages 5 through 12 years, with normal baseline EEGs. All had an additional EEG recorded after 24 hour sleep deprivation. Nine learning-impaired children had a history compatible with absence seizures; 8 of them showed spike-and-wave discharges after sleep deprivation. Of the 12 learning-impaired children with no history of absence seizures, 2 showed spike-and-wave discharges after sleep deprivation. These results are significant (p less than 0.001). Of the 7 controls, none had epileptiform activity following sleep deprivation. Our results show that routine EEGs may be falsely negative in patients with absence seizures, and that sleep deprivation is a potent activator.

Skill, content and generative strategies in autistic children's drawings

The drawing skill, picture content and strategies for generating ideas for drawings were compared in 20 drawings collected over the course of one year from 12 relatively able autistic children, not selected for drawing ability, and 12 learning‐impaired children. The drawing skills of the two groups and the content of their pictures were very similar. However, the autistic children generated ideas which were more closely related than those of the controls. The implications of the findings for our understanding of autism are discussed.

Cerebral Structure on Magnetic Resonance Imaging in Language- and Learning-Impaired Children

Using magnetic resonance imaging 20 language- and learning-impaired children were compared with 12 normal control subjects. Gross brain structure was remarkably normal in the language- and learning-impaired group. Semiautomated morphometry was used to measure hemispheric volumes and cerebral asymmetries in six cerebral regions. The volume of the left posterior perisylvian region was significantly reduced in language- and learning-impaired children. Asymmetries in inferoanterior and superoposterior cerebral regions were also significantly different in this group. Results of descriptive group comparisons of estimated volumes of other cerebral gray-matter structures raise the possibility that some language- and learning-impaired children may have additional volume reductions in cortical and subcortical structures. The results suggest that hemispheric specialization of function may be anomalous in this population.

Unexpected sex-ratios in families of language/ learning-impaired children: Evidence from genetic familial studies

Based on the increased incidence of boys to girls affected with developmental language impairments (LI), sex-linked models of genetic transmission were investigated. Family history data was collected on all first-degree relatives of a large, well-defined population of (LI) children and matched normal controls. Results demonstrated significant family aggregation in all first-degree relatives of LIs as compared to controls. Further analyses demonstrated that the expected higher male to female sex-ratio in LI children only occurred significantly in families with an affected parent. Affected mothers, but not fathers, demonstrated a significant sex-ratio difference among probands as well as increased frequency of other affected offspring. However, results failed to support sex-linkage hypotheses in that male and female probands had equal propensity to have an affected mother or father and did not differ in rate or sex of affected siblings. An unexpected finding was that the siblings of LI children also demonstrated a significantly aberrant sex-ratio. LI children had 65 brothers, but only 35 sisters (ratio 1.9:1). Analyses demonstrated that, whereas non-affected parents and affected fathers had the expected equal number of male and female offspring, affected mothers had three times as many male as female offspring and eight times as many affected males as females (excluding probands). Genetic and hormonal influences that might affect sex-ratio, brain development and neurodevelopmental disorders will be discussed.

Alternative thinking and classroom behavior of learning impaired children.

The impact of alternative thinking on overt behavior of learning impaired second and third graders (66 boys, 21 girls) was examined. Measures of alternative problem solutions, classroom behavior, and reading proficiency were obtained before and after subjects participated in a therapeutic tutoring program. Some subjects received formal training in interpersonal problem solving as well as tutoring while others received only tutoring. At pretest, number of alternative solutions correlated positively (not negatively as expected) to teachers' ratings of acting-out behavior for boys and positively (as expected) to “good-student” behavior by girls. Training in problem solving had no measurable effect on the number of alternative problem solutions generated or on classroom behavior but did lead to reduced reading gains. Increases in alternative problem solutions from pretest to posttest were associated with increases in acting-out behavior for both boys and girls. It is suggested that numerous alternative solutions may reflect impulsive or uncritical thinking rather than constructive social skills by learning disabled children.

Cerebral Dominance and Childhood Learning Disorders: Theoretical Perspectives

The present paper examined Orton's early hypothesis of inconsistent cerebral dominance for linguistically disabled children in light of some 50 years of research. After a brief review of the notion of hemispheric specialization, data from nonintrusive measures of functional asymmetry with learning impaired children was critically evaluated. Controlling for methodological difficulties, the available evidence concerning lateral performance and perceptual asymmetry for language was interpreted in favor of a hypothesis which postulates normal left-hemispheric asymmetry for auditory-verbal stimuli and a relative bilateralization of visual-verbal language for many linguistically disabled children. While data supporting such a theoretical formulation was found available, a history of inconsistent findings in this area suggests caution.

The Prevalence of Middle Ear Disease among Learning Impaired Children

The prevalence of middle ear disease among children who are educationally classified as learning disabled as compared to that found in normal children is discussed. A higher incidence of middle ear pathology was found among the learning impaired children. The potentially hazardous effects that middle ear disease can have upon academic and linguistic development are emphasized.

The Role of Art in Developing and Evaluating Cognitive Skills

Eleven graduate students who had registered for an elective course in art therapy worked under supervision with 11 unselected learning-impaired children. They used special art techniques designed to develop and evaluate ability to order, perceive, associate, and represent components. After 10 weekly one-hour art periods, the children showed significant gains in concepts of space, order, and class, as measured by pre- and post-tests designed for the study.