Hypothesis In Children Research Articles

An executive-functions-based reading training enhances sensory-motor systems integration during reading fluency in children with dyslexia.

The Simple View of Reading model suggests that intact language processing and word decoding lead to proficient reading comprehension, with recent studies pointing at executive functions as an important component contributing to reading proficiency. Here, we aimed to determine the underlying mechanism(s) for these changes. Participants include 120 8- to 12-year-old children (n = 55 with dyslexia, n = 65 typical readers) trained on an executive functions-based reading program, including pre/postfunctional MRI and behavioral data collection. Across groups, improved word reading was related to stronger functional connections within executive functions and sensory networks. In children with dyslexia, faster and more accurate word reading was related to stronger functional connections within and between sensory networks. These results suggest greater synchronization of brain systems after the intervention, consistent with the "neural noise" hypothesis in children with dyslexia and support the consideration of including executive functions as part of the Simple View of Reading model.

Continuous-time modeling of the multivariate relationships between physical activity levels and stationary time in preschool-aged children: an investigation of the ActivityStat hypothesis

BackgroundThe ActivityStat hypothesis proposes that an increase or decrease in physical activity (PA) greater than a certain set point activates behavioural and/or energy compensatory responses to maintain a stable level of total energy expenditure. Few studies have tested this hypothesis in children and even fewer have focused on young children. Therefore, the purpose of this study was to investigate the ActivityStat hypothesis by examining the presence and timeframe of the relationships among PA levels and stationary time (ST) in preschool-aged children.MethodsA secondary analysis was performed on repeated measurement data (i.e., day-to-day activity) involving 98 preschool-aged children (age: 4.5 ± 0.7 years) in Edmonton, Canada. Participants were asked to wear an ActiGraph wGT3X-BT on the waist for 7 consecutive days to assess PA levels (i.e., light PA [LPA], and moderate-to-vigorous PA[MVPA]) and ST. Bayesian continuous-time structural equation modeling (CT-SEM) was used to examine the relationship between behaviours over time and the timeframe during which these relationships occur.ResultsEach behaviour (i.e., LPA, MVPA, and ST) positively and meaningfully predicted itself at a later time. These relationships persisted up to 0.5 days later, at which point past behaviour no longer meaningfully predicted future behaviour. In contrast, no relationships were observed between the three behaviours.ConclusionsThis is the first study to investigate the ActivityStat hypothesis using Bayesian CT-SEM in preschool-aged children. When simultaneously taking into account all dynamic relationships suggested by the ActivityStat, the findings fail to support the hypothesis.

From child-peer similarity in imitative behavior to matched peer-mediated interventions in autism.

Self-consciousness develops through a long process, from pre-reflexive consciousness relying on body perception, to "meta" self-awareness. It emerges from the imitative experience between children and their peers. This experience linked to the capacity to test structural similarities between oneself and others, is addressed according to the concept of interpersonal affordance. We hypothesize that the opportunity for co-actors to engage in a process of interpersonal coordination is underlined by their similarity in terms of morphological, behavioral and motor features. This experience can sustain the emergence of new affordances for objects for each co-actor, as well as new affordances in terms of joint actions. We apply this idea in the context of peer-mediated interventions (PMI) in autism spectrum disorder (ASD). We argue that, in PMI, an encounter between children with autism and similar peers would foster the opportunity to engage in a spontaneous process of interpersonal coordination. This process would enable the development of self-consciousness and the emergence of perception of interpersonal, self and other's affordances for children with autism. We conclude that metrics to assess morphological, behavioral and motor similarity should then be defined and used in future studies to test our hypothesis in children with autism versus TD children or between children with autism.

Globus pallidus internus activity increases during voluntary movement in children with dystonia

The rate model of basal ganglia function predicts that muscle activity in dystonia is due to disinhibition of thalamus resulting from decreased inhibitory input from pallidum. We seek to test this hypothesis in children with dyskinetic cerebral palsy undergoing evaluation for deep brain stimulation (DBS) to analyze movement-related activity in different brain regions. The results revealed prominent beta-band frequency peaks in the globus pallidus interna (GPi), ventral oralis anterior/posterior (VoaVop) subnuclei of the thalamus, and subthalamic nucleus (STN) during movement but not at rest. Connectivity analysis indicated stronger coupling between STN-VoaVop and STN-GPi compared to GPi-STN. These findings contradict the hypothesis of decreased thalamic inhibition in dystonia, suggesting that abnormal patterns of inhibition and disinhibition, rather than reduced GPi activity, contribute to the disorder. Additionally, the study implies that correcting abnormalities in GPi function may explain the effectiveness of DBS targeting the STN and GPi in treating dystonia.

Evidence for protein leverage in a general population sample of children and adolescents

Background/ObjectivesThe strong regulation of protein intake can lead to overconsumption of total energy on diets with a low proportion of energy from protein, a process referred to as protein leverage. The protein leverage hypothesis posits that protein leverage explains variation in energy intake and potentially obesity in ecological settings. Here, we tested for protein leverage and the protein leverage hypothesis in children and adolescents.Subjects/MethodsA population sample of children, mean (SD) age 7.6 (0.4) years (n = 422), followed up at age 9.8 (0.4) years (n = 387) and at age 15.8 (0.4) years (n = 229), participating for the Physical Activity and Nutrition in Children (PANIC) study. Exposures: 4-day food records-related proportional energy intake of proteins, fats, and carbohydrates. Outcomes: energy intake, body mass index (BMI) z-score and dual-energy X-ray absorptiometry-related energy expenditure.ResultsProportional energy intake of proteins was inversely associated with energy intake following power functions at all 3 ages (mean [95%CI] strength of leverage of L = −0.36 [−0.47 to −0.25]; L = −0.26 [−0.37 to −0.15]; L = −0.25 [−0.38 to −0.13]; all P < 0.001). Mixture analysis indicated that variance in energy intake was associated primarily with the proportional intake of energy from proteins, not with either fats or carbohydrates. At all 3 ages, energy intake was not associated with BMI z-score but positively associated with energy expenditure (all P < 0.001).ConclusionsThis study provides evidence consistent with protein leverage in a population sample of children and adolescents. Increased energy intake on diets with lower protein content was counterbalanced by increased energy expenditure and therefore did not translate into increased adiposity.

A test of the effort equalization hypothesis in children with cerebral palsy who have an asymmetric gait.

Healthy people can walk nearly effortlessly thanks to their instinctively adaptive gait patterns that tend to minimize metabolic energy consumption. However, the economy of gait is severely impaired in many neurological disorders such as stroke or cerebral palsy (CP). Moreover, self-selected asymmetry of impaired gait does not seem to unequivocally coincide with the minimal energy cost, suggesting the presence of other adaptive origins. Here, we used hemiparetic CP gait as a model to test the hypothesis that pathological asymmetric gait patterns are chosen to equalize the relative muscle efforts between the affected and unaffected limbs. We determined the relative muscle efforts for the ankle and knee extensors by relating extensor joint moments during gait to maximum moments obtained from all-out hopping reference test. During asymmetric CP gait, the unaffected limb generated greater ankle (1.36±0.15 vs 1.17±0.16 Nm/kg, p = 0.002) and knee (0.74±0.33 vs 0.44±0.19 Nm/kg, p = 0.007) extensor moments compared with the affected limb. Similarly, the maximum moment generation capacity was greater in the unaffected limb versus the affected limb (ankle extensors: 1.81±0.39 Nm/kg vs 1.51±0.34 Nm/kg, p = 0.033; knee extensors: 1.83±0.37 Nm/kg vs 1.34±0.38 Nm/kg, p = 0.021) in our force reference test. As a consequence, no differences were found in the relative efforts between unaffected and affected limb ankle extensors (77±12% vs 80±16%, p = 0.69) and knee extensors (41±17% vs 38±23%, p = 0.54). In conclusion, asymmetric CP gait resulted in similar relative muscle efforts between affected and unaffected limbs. The tendency for effort equalization may thus be an important driver of self-selected gait asymmetry patterns, and consequently advantageous for preventing fatigue of the weaker affected side musculature.

Seizing the opportunity: Lifespan differences in the effects of the opportunity cost of time on cognitive control

Previous work suggests that lifespan developmental differences in cognitive control reflect maturational and aging-related changes in prefrontal cortex functioning. However, complementary explanations exist: It could be that children and older adults differ from younger adults in how they balance the effort of engaging in control against its potential benefits. Here we test whether the degree of cognitive effort expenditure depends on the opportunity cost of time (average reward rate per unit time): if the average reward rate is high, participants should withhold cognitive effort whereas if it is low, they should invest more. In Experiment 1, we examine this hypothesis in children, adolescents, younger, and older adults, by applying a reward rate manipulation in two cognitive control tasks: a modified Erikson Flanker and a task-switching paradigm. We found that young adults and adolescents reflexively withheld effort when the opportunity cost of time was high, whereas older adults and, to a lesser degree children, invested more resources to accumulate reward as quickly as possible. We tentatively interpret these results in terms of age- and task-specific differences in the processing of the opportunity cost of time. We qualify our findings in a second experiment in younger adults in which we address an alternative explanation of our results and show that the observed age differences in effort expenditure may not result from differences in task difficulty.To conclude, we think that our results present an interesting first step at relating opportunity costs to motivational processes across the lifespan. We frame the implications of further work in this area within a recent developmental model of resource-rationality, which points to developmental sweet spots in cognitive control.

Procedural Learning, Grammar, and Motor Skills in Children With Childhood Apraxia of Speech, Speech Sound Disorder, and Typically Developing Speech

Purpose This case-control study sought to determine if (a) children with childhood apraxia of speech (CAS), other speech sound disorders (SSDs), and typical development would perform differently on a procedural learning assessment and (b) whether grammatical ability would impact group differences. Method Communication, motor, and procedural learning abilities were assessed in 48 children with CAS (n = 13), SSD (n = 20), and typical development (n = 15), between 43 and 97 months of age (M = 66 months, SD = 12 months). Results On average, children with CAS demonstrated grammatical and motor impairments and required an increased number of exposures to the visuospatial sequence to demonstrate procedural learning, compared to peers with SSD or typical development. A subset of children from each group demonstrated an unanticipated procedural learning pattern wherein they evidenced an uptick in reaction time during the second sequenced block. Children with CAS with this pattern still evidenced procedural learning gains by the fifth sequenced block. In contrast, children with SSD and typical development with this pattern showed poor procedural learning outcomes and were characterized by lower scores on language and motor assessments as well. Conclusions This research provides partial support for the procedural learning deficit hypothesis in children with CAS and for a subset of children with SSD as well. Future research should examine the role of a serial reaction time task in identifying children at risk of multisystem communication and motor deficits. Supplemental Material https://doi.org/10.23641/asha.14173532.

Activation of Functional Brain Networks in Children With Psychogenic Non-epileptic Seizures

ObjectivesPsychogenic non-epileptic seizures (PNES) have been hypothesized to emerge in the context of neural networks instability. To explore this hypothesis in children, we applied a graph theory approach to examine connectivity in neural networks in the resting-state EEG in 35 children with PNES, 31 children with other functional neurological symptoms (but no PNES), and 75 healthy controls.MethodsThe networks were extracted from Laplacian-transformed time series by a coherence connectivity estimation method.ResultsChildren with PNES (vs. controls) showed widespread changes in network metrics: increased global efficiency (gamma and beta bands), increased local efficiency (gamma band), and increased modularity (gamma and alpha bands). Compared to controls, they also had higher levels of autonomic arousal (e.g., lower heart variability); more anxiety, depression, and stress on the Depression Anxiety and Stress Scales; and more adverse childhood experiences on the Early Life Stress Questionnaire. Increases in network metrics correlated with arousal. Children with other functional neurological symptoms (but no PNES) showed scattered and less pronounced changes in network metrics.ConclusionThe results indicate that children with PNES present with increased activation of neural networks coupled with increased physiological arousal. While this shift in functional organization may confer a short-term adaptive advantage—one that facilitates neural communication and the child’s capacity to respond self-protectively in the face of stressful life events—it may also have a significant biological cost. It may predispose the child’s neural networks to periods of instability—presenting clinically as PNES—when the neural networks are faced with perturbations in energy flow or with additional demands.

Assessing the unified airway hypothesis in children via transcriptional profiling of the airway epithelium

Emerging evidence suggests that disease vulnerability is expressed throughout the airways, the so-called unified airway hypothesis, but the evidence to support this is predominantly indirect. We sought to establish the transcriptomic profiles of the upper and lower airways and determine their level of similarity irrespective of airway symptoms (wheeze) and allergy. We performed RNA sequencing on upper and lower airway epithelial cells from 63 children with or without wheeze and accompanying atopy, using differential gene expression and gene coexpression analyses to determine transcriptional similarity. We observed approximately 91% homology in the expressed genes between the 2 sites. When coexpressed genes were grouped into modules relating to biological functions, all were found to be conserved between the 2 regions, resulting in a consensus network containing 16 modules associated with ribosomal function, metabolism, gene expression, mitochondrial activity, and antiviral responses through IFN activity. Although symptom-associated gene expression changes were more prominent in the lower airway, they were reflected in nasal epithelium and included IL-1 receptor like 1, prostaglandin-endoperoxide synthase 1, CCL26, and periostin. Through network analysis we identified a cluster of coexpressed genes associated with atopic wheeze in the lower airway, which could equally distinguish atopic and nonatopic phenotypes in upper airway samples. We show that the upper and lower airways are significantly conserved in their transcriptional composition, and that variations associated with disease are present in both nasal and tracheal epithelium. Findings from this study supporting a unified airway imply that clinical insight regarding the lower airway in health and disease can be gained from studying the nasal epithelium.

Um estudo sobre o acento gráfico na aquisição da escrita: ortografia e fonologia

This paper discusses the criteria used by third and fifth graders who attend a public school, in Pelotas, RS, Brazil, regarding the function of diacritical marks in the writing system. Considering the close relationship between prosodic stress and the rules of use of diacritical marks, the study reported in this paper aimed at investigating children's hypotheses concerningthese orthographic devices. Data were collected by a controlled writing instrument, which was especially designed for this research, and by clinical interviews guided by the Piagetian method (Carraher, 1989). After completing awriting task, children were induced to explain the reasons that led them to usediacritics in their spelling. The analysis of data on their written production showed that children got the diacritical mark right, mainly in contexts in which alternation of vowel timbre could occur, that is, in medium and low medium vowels. Results of the interviews highlighted the emergence of criteria based on acoustic and graphic aspects. The analysis allowed us to define a hierarchy of acoustic criteria, i. e., vocalic timbre, vowel duration and prominence.

Sticking to the Evidence? A Behavioral and Computational Case Study of Micro-Theory Change in the Domain of Magnetism.

Constructing an intuitive theory from data confronts learners with a "chicken-and-egg" problem: The laws can only be expressed in terms of the theory's core concepts, but these concepts are only meaningful in terms of the role they play in the theory's laws; how can a learner discover appropriate concepts and laws simultaneously, knowing neither to begin with? We explore how children can solve this chicken-and-egg problem in the domain of magnetism, drawing on perspectives from computational modeling and behavioral experiments. We present 4- and 5-year-olds with two different simplified magnet-learning tasks. Children appropriately constrain their beliefs to two hypotheses following ambiguous but informative evidence. Following a critical intervention, they learn the correct theory. In the second study, children infer the correct number of categories given no information about the possible causal laws. Children's hypotheses in these tasks are explained as rational inferences within a Bayesian computational framework.

Impairment of non-symbolic number processing in children with mathematical learning disability

The functional origin of Mathematical Learning Disability (MLD), an impairment affecting mathematics learning, remains controversial. We aimed to study the number sense deficit hypothesis in children with MLD. We explored the processing of non-symbolic numbers in Quebec French-speaking 8‒9-year-old children with three non-symbolic tasks (number comparison, number matching and dot set selection task). Results showed that children with MLD were as successful as typically developing children in a comparison task, but less successful in a matching task. Their performance in numerical re-production was also similar to that of typically developing children for large (10-99) numerosities, while they were less successful in transcoding small (1-4) and medium (5-9) numerosities. Children with MLD also presented with general cognitive and reading difficulties. Results suggest a deficit in processing small and medium numerosities in children with MLD that could be largely attributed to their poorer cognitive skills.

A test of the Environmental Stress Hypothesis in children with and without Developmental Coordination Disorder

ObjectivesThis study examined several underlying mechanisms hypothesized by the Environmental Stress Hypothesis (ESH) to explain the association between probable Developmental Coordination Disorder (pDCD) and internalizing problems. Design/MethodA cross-sectional analysis involving 1206 children aged 12–14 years (79 pDCD, 6.6% of the sample) was conducted. Children received assessments of motor coordination, physical activity, BMI, global self-worth, and internalizing problems. Path analysis was conducted to examine overall model fit and sex differences. ResultsThe results showed significant sex differences in the underlying pathways connecting pDCD to internalizing problems, indicating more mediating pathways through physical activity, BMI and global self-worth in girls, compared to boys. ConclusionsOverall, we were able to find support for some of the pathways identified in the ESH in school-aged children. Results also suggest that the development of interventions may need to be sex specific.

Evaluating the Causal Link Between Malaria Infection and Endemic Burkitt Lymphoma in Northern Uganda: A Mendelian Randomization Study

BackgroundPlasmodium falciparum (Pf) malaria infection is suspected to cause endemic Burkitt Lymphoma (eBL), but the evidence remains unsettled. An inverse relationship between sickle cell trait (SCT) and eBL, which supports that between malaria and eBL, has been reported before, but in small studies with low power. We investigated this hypothesis in children in a population-based study in northern Uganda using Mendelian Randomization. MethodsMalaria-related polymorphisms (SCT, IL10, IL1A, CD36, SEMA3C, and IFNAR1) were genotyped in 202 eBL cases and 624 controls enrolled during 2010–2015. We modeled associations between genotypes and eBL or malaria using logistic regression. FindingsSCT was associated with decreased risk of eBL (adjusted odds ratio [OR] 0·37, 95% CI 0·21–0·66; p=0·0003). Decreased risk of eBL was associated with IL10 rs1800896-CT (OR 0·73, 95% CI 0·50–1·07) and -CC genotypes (OR 0·53, 95% CI 0·29–0·95, ptrend=0·019); IL1A rs2856838-AG (OR 0·56, 95% CI 0·39–0·81) and -AA genotype (OR 0·50, 95% CI 0·28–1·01, ptrend=0·0016); and SEMA3C rs4461841-CT or -CC genotypes (OR 0·57, 95% CI 0·35–0·93, p=0·0193). SCT and IL10 rs1800896, IL1A rs2856838, but not SEMA3C rs4461841, polymorphisms were associated with decreased risk of malaria in the controls. InterpretationOur results support a causal effect of malaria infection on eBL.

The Voice of Holland: Allograph Production in Written Dutch Past Tense Inflection

ABSTRACTAccording to the Integration of Multiple Patterns hypothesis (IMP; Treiman & Kessler, 2014), the spelling difficulty of a word is affected by the number of cues converging on the correct answer. We tested this hypothesis in children’s regular past tense formation in Dutch. Past tenses are formed by adding either-de or-te to a verb stem. Despite instruction, children often choose the wrong allograph. In a large dataset (227 items, together completed 392,802 times) from an online language program we assessed whether morphophonological and orthographic cues determine differences in difficulty and explain error patterns. Regression analyses established that inflection difficulty was affected by number of converging cues, especially morphophonological and orthographic cues. Error analyses further showed that allograph errors were prominent when graphotactic frequency and especially voicing probability collided with the correct answer. The results match and specify the IMP. Proposals are made to use this knowledge in educational practice.

Educational expansion without equalization: a reappraisal of the ‘Effectively Maintained Inequality’ hypothesis in children’s choice of the upper secondary track

ABSTRACTPrevious studies of trends in social inequalities in upper secondary track choices in Italy found evidence that, in the period of highest educational expansion, horizontal inequalities increased, consistently with the Effectively Maintained Inequality thesis (EMI). Our paper, focusing on the youngest birth cohorts (1958–1989), documents that enrolments at upper secondary schools have become almost universal and have been followed by a huge expansion of the academic track. Although the latter has also involved children from the lowest social strata, our evidence suggests that their relative disadvantage to attend the academic track, compared to the most privileged social groups, has diminished only slightly. When distinguishing between different curricula within the academic track, we found evidence supporting the EMI hypothesis also among recent cohorts: the expansion of the academic track has gone hand-in-hand with increasing social inequalities in the chances to attend more prestigious curricula. Finally, social class inequalities in the chances of enrolling at the academic track are stronger at high levels of parental education, while they are largely muted among low-educated parents. We suggest the latter as a possible mechanism to explain why educational expansion may not produce a decline in the association between social origins and educational attainment.

5-HTTLPR Expression Outside the Skin: An Experimental Test of the Emotional Reactivity Hypothesis in Children.

BackgroundThere is increasing evidence that variation in the promoter region of the serotonin transporter gene SLC6A4 (i.e., the 5-HTTLPR polymorphism) moderates the impact of environmental stressors on child psychopathology. Emotional reactivity −the intensity of an individual’s response to other’s emotions− has been put forward as a possible mechanism underlying these gene-by-environment interactions (i.e., G×E). Compared to children homozygous for the L-allele (LL-genotypes), children carrying an S-allele (SS/SL-genotypes), specifically when they have been frequently exposed to negative emotions in the family environment, might be more emotionally reactive and therefore more susceptible to affective environmental stressors. However, the association between 5-HTTLPR and emotional reactivity in children has not yet been empirically tested. Therefore, the goal of this study was to test this association in a large-scale experiment.MethodsChildren (N = 521, 52.5% boys, Mage = 9.72 years) were genotyped and randomly assigned to happy, angry or neutral dynamic facial expressions and vocalizations. Motor and affective emotional reactivity were assessed through children’s self-reported negative and positive affect (n = 460) and facial electromyography activity (i.e., fEMG: the zygomaticus or “smile” muscle and the corrugator or “frown” muscle, n = 403). Parents reported on their negative and positive parenting behaviors.ResultsChildren mimicked and experienced the emotion they were exposed to. However, neither motor reactivity nor affective reactivity to these emotions depended on children’s 5-HTTLPR genotype: SS/SL-genotypes did not manifest any stronger response to emotional stimuli than LL-genotypes. This finding remained the same when taking the broader family environment into account, controlling for kinship, age, gender and genetic ancestry, and when including a tri-allelic factor.ConclusionsWe found no evidence for an association between the 5-HTTLPR polymorphism and children’s emotional reactivity. This finding is important, in discounting one potential underlying endophenotype of G×E between the 5-HTTLPR and affective environmental stressors.

The Confusion of Fear and Surprise: A Developmental Study of the Perceptual-Attentional Limitation Hypothesis Using Eye Movements

ABSTRACTThe goal of the present study was to test the Perceptual-Attentional Limitation Hypothesis in children and adults by manipulating the distinctiveness between expressions and recording eye movements. Children 3–5 and 9–11 years old as well as adults were presented pairs of expressions and required to identify a target emotion. Children 3–5 years old were less accurate than those 9–11 years old and adults. All children viewed pictures longer than adults but did not spend more time attending to the relevant cues. For all participants, accuracy for the recognition of fear was lower than for surprise when the distinctive cue was in the brow only. They also took longer and spent more time in both the mouth and brow zones than when a cue was in the mouth or both areas. Adults and children 9–11 years old made more comparisons between the expressions when fear comprised a single distinctive cue in the brow than when the distinctive cue was in the mouth only or when both cues were present. Children 3–5 years old made more comparisons for brow only than both. The results of the present study extend on the Perceptual-Attentional Limitation Hypothesis showing an importance of both decoder and stimuli, and an interaction between decoder and stimuli characteristics.

Gesture and speech during shared book reading with preschoolers with specific language impairment.

This study examined (a) the relationship between gesture and speech produced by children with specific language impairment (SLI) and typically developing (TD) children, and their mothers, during shared book-reading, and (b) the potential effectiveness of gestures accompanying maternal speech on the conversational responsiveness of children. Fifteen preschoolers with expressive SLI were compared with fifteen age-matched and fifteen language-matched TD children. Child and maternal utterances were coded for modality, gesture type, gesture-speech informational relationship, and communicative function. Relative to TD peers, children with SLI used more bimodal utterances and gestures adding unique information to co-occurring speech. Some differences were mirrored in maternal communication. Sequential analysis revealed that only in the SLI group maternal reading accompanied by gestures was significantly followed by child's initiatives, and when maternal non-informative repairs were accompanied by gestures, they were more likely to elicit adequate answers from children. These findings support the 'gesture advantage' hypothesis in children with SLI, and have implications for educational and clinical practice.