Development of integrated jaw-neck motor function in children at 6, 10 and 13 years of age compared to adults: A kinematic longitudinal study

BACKGROUND

The functional integration of the jaw and neck motor systems, of great importance to everyday oral activities, is established in early childhood. Detailed characterisation of this developmental progress is largely unknown.

OBJECTIVE

To establish developmental changes in jaw-neck motor function in children over the ages 6-13 years compared to adults.

METHODS

Jaw and head movement kinematics during jaw opening-closing and chewing were longitudinally recorded in 20 Swedish children (8 girls) at 6 (6.3 ± 0.4), 10 (10.3 ± 0.3) and 13 (13.5 ± 0.7) years of age and 20 adults (9 women, 28.2 ± 6.7). Movement amplitudes, jaw movement cycle time (CT), coefficient of variation (CV) and head/jaw ratio for amplitudes were analysed. Linear mixed effect analysis and Welch's t-test were used.

RESULTS

Children showed pronounced movement variability and longer CT at 6 and 10 years old during opening and chewing (p < .001). Compared to adults, 6-year-olds showed higher head/jaw ratios (p < .02) and longer CT (p < .001) during opening and chewing, and higher CV-head (p < .001) during chewing. Whereas 10-year-olds showed larger jaw and head amplitudes (p < .02) and longer CT (p < .001) during opening, and longer CT (p < .001) and higher CV-head (p < .001) during chewing. For 13-year-olds, longer CT (p < .001) during chewing was found.

CONCLUSION

Children showed pronounced movement variability and longer movement cycle time at 6-10 years and developmental progress in jaw-neck integration from 6 to 13 years, with 13-year-olds displaying adult-like movements. These results add new detailed understanding to the typical development of integrated jaw-neck motor function.

Behavioral and Neuroimaging Research on Developmental Coordination Disorder (DCD): A Combined Systematic Review and Meta-Analysis of Recent Findings

AIM

The neurocognitive basis of Developmental Coordination Disorder (DCD; or motor clumsiness) remains an issue of continued debate. This combined systematic review and meta-analysis provides a synthesis of recent experimental studies on the motor control, cognitive, and neural underpinnings of DCD.

METHODS

The review included all published work conducted since September 2016 and up to April 2021. One-hundred papers with a DCD-Control comparison were included, with 1,374 effect sizes entered into a multi-level meta-analysis.

RESULTS

The most profound deficits were shown in: voluntary gaze control during movement; cognitive-motor integration; practice-/context-dependent motor learning; internal modeling; more variable movement kinematics/kinetics; larger safety margins when locomoting, and atypical neural structure and function across sensori-motor and prefrontal regions.

INTERPRETATION

Taken together, these results on DCD suggest fundamental deficits in visual-motor mapping and cognitive-motor integration, and abnormal maturation of motor networks, but also areas of pragmatic compensation for motor control deficits. Implications for current theory, future research, and evidence-based practice are discussed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, identifier: CRD42020185444.

Motor planning and movement execution during goal-directed sequential manual movements in 6-year-old children with autism spectrum disorder: A kinematic analysis

BACKGROUND

Atypical motor functioning is prevalent in children with autism spectrum disorder (ASD). Knowledge of the underlying kinematic properties of these problems is sparse.

AIMS

To investigate characteristics of manual motor planning and performance difficulties/diversity in children with ASD by detailed kinematic measurements. Further, associations between movement parameters and cognitive functions were explored.

METHODS AND PROCEDURES

Six-year-old children with ASD (N = 12) and typically developing (TD) peers (N = 12) performed a sequential manual task comprising grasping and fitting a semi-circular peg into a goal-slot. The goal-slot orientation was manipulated to impose different motor planning constraints. Movements were recorded by an optoelectronic system.

OUTCOMES AND RESULTS

The ASD-group displayed less efficient motor planning than the TD-group, evident in the reach-to-grasp and transport kinematics and less proactive adjustments of the peg to the goal-slot orientations. The intra-individual variation of movement kinematics was higher in the ASD-group compared to the TD-group. Further, in the ASD-group, movement performance associated negatively with cognitive functions.

CONCLUSIONS AND IMPLICATIONS

Planning and execution of sequential manual movements proved challenging for children with ASD, likely contributing to problems in everyday actions. Detailed kinematic investigations contribute to the generation of specific knowledge about the nature of atypical motor performance/diversity in ASD. This is of potential clinical relevance.

Neurodevelopment and growth until 6.5 years of infants who consumed a low-energy, low-protein formula supplemented with bovine milk fat globule membranes: a randomized controlled trial

BACKGROUND

We previously reported results from a randomized controlled trial in which we found that Swedish infants consuming an experimental low-energy, low-protein formula (EF) supplemented with bovine milk fat globule membranes (MFGMs) until 6 mo of age had several positive outcomes, including better performance in the cognitive domain of Bayley Scales of Infant and Toddler Development 3rd Edition at 12 mo of age, and higher plasma cholesterol concentrations during the intervention, than infants consuming standard formula (SF).

OBJECTIVES

We aimed to evaluate neurodevelopment, growth, and plasma cholesterol status at 6 and 6.5 y of age in the same study population.

METHODS

We assessed cognitive and executive functions using the Wechsler Intelligence Scale for Children 4th Edition (WISC-IV), Brown Attention-Deficit Disorder Scales for Children and Adolescents (Brown-ADD), and Quantified Behavior (Qb) tests, and behavior using the Child Behavior Checklist (CBCL) and Teacher's Report Form (TRF), at 6.5 y of age. Anthropometrics and plasma lipids were assessed at 6 y of age.

RESULTS

There were no differences between the EF and SF groups in any of the subscales in WISC-IV or Brown-ADD at 6.5 y of age, in the proportion of children with scores outside the normal range in the Qb test, nor in clinical or borderline indications of problems in adaptive functioning from parental and teacher's scoring using the CBCL and TRF. There were no differences between the EF and SF groups in weight, length, or head or abdominal circumferences, nor in plasma concentrations of homocysteine, lipids, insulin, or glucose.

CONCLUSIONS

Among children who as infants consumed a low-energy, low-protein formula supplemented with bovine MFGMs, there were no effects on neurodevelopment, growth, or plasma cholesterol status 6-6.5 y later.

The Effects of Working Memory Updating Training in Parkinson's Disease: A Feasibility and Single-Subject Study on Cognition, Movement and Functional Brain Response

In Parkinson’s disease (PD), the fronto-striatal network is involved in motor and cognitive symptoms. Working memory (WM) updating training engages this network in healthy populations, as observed by improved cognitive performance and increased striatal BOLD signal. This two-part study aimed to assess the feasibility of WM updating training in PD and measure change in cognition, movement and functional brain response in one individual with PD after WM updating training. A feasibility and single-subject (FL) study were performed in which patients with PD completed computerized WM updating training. The outcome measures were the pre-post changes in criterion and transfer cognitive tests; cognitive complaints; psychological health; movement kinematics; and task-related BOLD signal. Participants in the feasibility study showed improvements on the criterion tests at post-test. FL displayed the largest improvements on the criterion tests and smaller improvements on transfer tests. Furthermore, FL reported improved cognitive performance in everyday life. A shorter onset latency and smoother upper-limb goal-directed movements were measured at post-test, as well as increased activation within the striatum and decreased activation throughout the fronto-parietal WM network. This two-part study demonstrated that WM updating training is feasible to complete for PD patients and that change occurred in FL at post-test in the domains of cognition, movement and functional brain response.

Upper-extremity Spasticity-reducing Treatment in Adjunct to Movement Training and Orthoses in Children with Cerebral Palsy at Gross Motor Function- and Manual Ability Classification System Levels IV-V: A Descriptive Study

Covering a 20-year period of work with children with severe cerebral palsy (CP) within a Swedish habilitation service, changes in passive wrist extension with fingers extended (PWE-FE) and current hand function are described and compared between children receiving systematic upper-extremity treatment with botulinum neurotoxin type A and intervention programs from before 7 years of age (Group 1, n = 7), those whom for various reasons did not undergo this treatment (Group 2, n = 10), and those not having the option to receive treatment until later during childhood/adolescence (Group 3, n = 8). Group 3 showed more critical and less normal PWE-FE values for both wrists, and poorer hand function scores, particularly compared with Group 1. Findings cautiously suggest that repeated upper-extremity spasticity-reducing treatment and movement training/orthoses from an early age may help prevent critical loss of passive range of motion of the wrist joint flexion/extension and promote hand function development in children with severe CP.

Maternal blood folate status during early pregnancy and occurrence of autism spectrum disorder in offspring: a study of 62 serum biomarkers

BACKGROUND

Autism spectrum disorder (ASD) evolves from an interplay between genetic and environmental factors during prenatal development. Since identifying maternal biomarkers associated with ASD risk in offspring during early pregnancy might result in new strategies for intervention, we investigated maternal metabolic biomarkers in relation to occurrence of ASD in offspring using both univariate logistic regression and multivariate network analysis.

METHODS

Serum samples from 100 women with an offspring diagnosed with ASD and 100 matched control women with typically developing offspring were collected at week 14 of pregnancy. Concentrations of 62 metabolic biomarkers were determined, including amino acids, vitamins (A, B, D, E, and K), and biomarkers related to folate (vitamin B₉) metabolism, lifestyle factors, as well as C-reactive protein (CRP), the kynurenine-tryptophan ratio (KTR), and neopterin as markers of inflammation and immune activation.

RESULTS

We found weak evidence for a positive association between higher maternal serum concentrations of folate and increased occurrence of ASD (OR per 1 SD increase: 1.70, 95% CI 1.22-2.37, FDR adjusted P = 0.07). Multivariate network analysis confirmed expected internal biochemical relations between the biomarkers. Neither inflammation markers nor vitamin D₃ levels, all hypothesized to be involved in ASD etiology, displayed associations with ASD occurrence in the offspring.

CONCLUSIONS

Our findings suggest that high maternal serum folate status during early pregnancy may be associated with the occurrence of ASD in offspring. No inference about physiological mechanisms behind this observation can be made at the present time because blood folate levels may have complex relations with nutritional intake, the cellular folate status and status of other B-vitamins. Therefore, further investigations, which may clarify the potential role and mechanisms of maternal blood folate status in ASD risk and the interplay with other potential risk factors, in larger materials are warranted.

Risk for Behavioral Problems Independent of Cognitive Functioning in Children Born at Low Gestational Ages

This study aimed to investigate cognitive and behavioral outcomes in relation to gestational age (GA) in school-aged children born preterm (PT). Results from the Wechsler Intelligence Scale for Children, 4th edition (WISC-IV), and the Child Behavior Checklist (CBCL) were analyzed in 51 children (mean age: 7.8 years [range: 7.0-8.7]) born PT (mean GA: 31 weeks [range: 23-35]; birth weight, mean: 1,637 g [range: 404-2,962]) with the majority (96%) having no diagnosed cognitive, sensory, or motor impairments. The control group included 57 age-matched typically developing children (mean age: 7.9 years [range: 6.2-8.7]) born full-term (FT). Children born PT, extremely PT (GA < 28) in particular, showed significantly lower cognitive performance and higher behavioral problem scores compared with children born FT. GA was found to predict aspects of both cognitive functioning and behavioral problems within the PT group, with lower GA being related to both poorer cognitive outcomes and elevated affective and attention-deficit/hyperactivity problems. Global cognitive functioning did not independently predict aspects of behavioral outcomes. Findings demonstrate that, even in children born PT without severe perinatal and/or postnatal complications and receiving active perinatal care, a short gestation is an evident risk factor for long-term negative effects on mental health independent of cognitive functioning. Additional findings suggest that both reduced growth and lower parental educational level may contribute to increased risk for poorer cognitive and behavioral functioning in children born PT.

Kinematic characteristics of second-order motor planning and performance in 6- and 10-year-old children and adults: Effects of age and task constraints

This study explored age-related differences in motor planning as expressed in arm-hand kinematics during a sequential peg moving task with varying demands on goal insertion complexity (second-order planning). The peg was a vertical cylinder with either a circular or semicircular base. The task was to transport the peg between two positions and rotate it various amounts horizontally before fitting into its final position. The amount of rotation required was either 0°, 90°, 180°, or -90°. The reaching for the peg, the displacement of it, and the way the rotation was accomplished was analyzed. Assessments of end state comfort, goal interpretation errors, and type of grip used were also included. Participants were two groups of typically developing children, one younger (M_age  = 6.7 years) and one older (M_age  = 10.3 years), and one adult group (M_age  = 34.9 years). The children, particularly 6-year-olds, displayed less efficient prehensile movement organization than adults. Related to less efficient motor planning, 6-year-olds, mainly, had shorter reach-to-grasp onset latencies, higher velocities, and shorter time to peak velocities, and longer grasp durations than adults. Importantly, the adults rotated the peg during transport. In contrast, the children made corrective rotations after the hand had arrived at the goal.

Developmental progression and side specialization in upper-limb movements from 4 to 8 years in children born preterm and fullterm

This study investigated developmental changes and differences in upper-limb movement organization from 4 to 8 years of age in children born preterm (PT) and fullterm (FT). Kinematic recordings of precision-demanding unimanual movements and lateral assessments were carried out in 37 children (18 PT). All children, particularly children born PT, displayed considerable gain in movement kinematics. Contrary to controls, children born PT displayed persistently less-evident side preference. Gestational age (GA) contributed significantly to kinematic differences shown, with larger upper-limb deviances in the lowest GAs, in agreement with cross-sectional findings of altered hemispheric connections and delayed side-specialization among children born very PT.

Alterations in white matter microstructure are associated with goal-directed upper-limb movement segmentation in children born extremely preterm

Altered white matter microstructure is commonly found in children born preterm (PT), especially those born at an extremely low gestational age (GA). These children also commonly show disturbed motor function. This study explores the relation between white matter alterations and upper-limb movement segmentation in 41 children born PT (19 girls), and 41 children born at term (18 girls) at 8 years. The PT group was subdivided into extremely PT (E-PT; GA = 25-27 weeks, N = 10), very PT (V-PT; GA = 28-32 weeks, N = 13), and moderately PT (M-PT; GA = 33-35 weeks, N = 18). Arm/hand preference (preferred/non-preferred) was determined through object interactions and the brain hemispheres were designated accordingly. White matter alterations were assessed using diffusion tensor imaging in nine areas, and movement segmentation of the body-parts head, shoulder, elbow, and wrist were registered during a unimanual goal-directed task. Increased movement segmentation was demonstrated consistently on the preferred side in the E-PT group compared with the term born group. Also compared with the term born peers, the E-PT group demonstrated reduced fractional anisotropy (FA) in the cerebral peduncle (targeting the corticospinal tract) in the hemisphere on the non-preferred side and in the splenium of corpus callosum. In contrast, in the anterior internal capsule on the preferred side, the E-PT group had increased FA. Lower FA in the cerebral peduncle, but higher FA in the anterior internal capsule, was associated with increased movement segmentation across body-parts in a contralateral manner. The results suggest that impaired development of sensorimotor tracts in E-PT children could explain a sub-optimal spatiotemporal organization of upper-limb movements. Hum Brain Mapp 38:5051-5068, 2017. © 2017 Wiley Periodicals, Inc.

Infant manual performance during reaching and grasping for objects moving in depth

Few studies have investigated manual performance in infants when reaching and grasping for objects moving in directions other than across the fronto-parallel plane. The present preliminary study explored object-oriented behavioral strategies and side preference in 8- and 10-month-old infants during reaching and grasping for objects approaching in depth from three positions (midline, and 27° diagonally from the left and right). Effects of task constraint by using objects of three different types and two sizes were further examined for behavioral strategies and hand opening prior to grasping. Additionally, assessments of hand preference by a dedicated handedness test were performed. Regardless of object starting position, the 8-month-old infants predominantly displayed right-handed reaches for objects approaching in depth. In contrast, the older infants showed more varied strategies and performed more ipsilateral reaches in correspondence with the side of the approaching object. Conversely, 10-month-old infants were more successful than the younger infants in grasping the objects, independent of object starting position. The findings regarding infant hand use strategies when reaching and grasping for objects moving in depth are similar to those from earlier studies using objects moving along a horizontal path. Still, initiation times of reaching onset were generally long in the present study, indicating that the object motion paths seemingly affected how the infants perceived the intrinsic properties and spatial locations of the objects, possibly with an effect on motor planning. Findings are further discussed in relation to future investigations of infant reaching and grasping for objects approaching in depth.

Short- and Long-Term Effects of Child Neuropsychological Assessment With a Collaborative and Therapeutic Approach: A Preliminary Study

This preliminary study explored if a collaborative and therapeutic approach (CTA) could reduce self-reported psychiatric symptoms (Beck Youth Inventories [BYI]) in children referred for neuropsychological assessment. Participants included 11 children (M(age )= 12.4 years) receiving CTA, 11 (M(age) = 12.6 years) receiving parent support, and 9 (M(age) = 12.3 years) remaining on a waiting list. Contrary to both comparison groups, the CTA group reported fewer psychiatric symptoms on most BYI subscales after intervention, and this decrease was sustained for the Anger and Anxiety subscales at 6-month follow-up. Findings support a potential effectiveness of CTA in the neuropsychological assessment of children in a child psychiatric setting.

Training of goal directed arm movements with motion interactive video games in children with cerebral palsy - a kinematic evaluation

OBJECTIVE

The main aim of this study was to evaluate the quality of goal-directed arm movements in 15 children with cerebral palsy (CP) following four weeks of home-based training with motion interactive video games. A further aim was to investigate the applicability and characteristics of kinematic parameters in a virtual context in comparison to a physical context.

METHOD

Kinematics and kinetics were captured while the children performed arm movements directed towards both virtual and physical targets.

RESULTS

The children's movement precision improved, their centre of pressure paths decreased, as did the variability in maximal shoulder angles when reaching for virtual objects. Transfer to a situation with physical targets was mainly indicated by increased movement smoothness.

CONCLUSION

Training with motion interactive games seems to improve arm motor control in children with CP. The results highlight the importance of considering both the context and the task itself when investigating kinematic parameters.

Early influence of auditory stimuli on upper-limb movements in young human infants: an overview

Given that the auditory system is rather well developed at the end of the third trimester of pregnancy, it is likely that couplings between acoustics and motor activity can be integrated as early as at the beginning of postnatal life. The aim of the present mini-review was to summarize and discuss studies on early auditory-motor integration, focusing particularly on upper-limb movements (one of the most crucial means to interact with the environment) in association with auditory stimuli, to develop further understanding of their significance with regard to early infant development. Many studies have investigated the relationship between various infant behaviors (e.g., sucking, visual fixation, head turning) and auditory stimuli, and established that human infants can be observed displaying couplings between action and environmental sensory stimulation already from just after birth, clearly indicating a propensity for intentional behavior. Surprisingly few studies, however, have investigated the associations between upper-limb movements and different auditory stimuli in newborns and young infants, infants born at risk for developmental disorders/delays in particular. Findings from studies of early auditory-motor interaction support that the developing integration of sensory and motor systems is a fundamental part of the process guiding the development of goal-directed action in infancy, of great importance for continued motor, perceptual, and cognitive development. At-risk infants (e.g., those born preterm) may display increasing central auditory processing disorders, negatively affecting early sensory-motor integration, and resulting in long-term consequences on gesturing, language development, and social communication. Consequently, there is a need for more studies on such implications.

Neurodevelopment, nutrition, and growth until 12 mo of age in infants fed a low-energy, low-protein formula supplemented with bovine milk fat globule membranes: a randomized controlled trial

BACKGROUND

Observational studies have indicated that differences in the composition of human milk and infant formula yield benefits in cognitive development and early growth for breastfed infants.

OBJECTIVE

The objective was to test the hypothesis that feeding an infant formula with reduced energy and protein densities and supplemented with bovine milk fat globule membrane (MFGM) reduces differences in cognitive development and early growth between formula-fed and breastfed infants.

DESIGN

In a prospective, double-blind, randomized controlled trial, 160 infants <2 mo of age were randomly assigned to be fed an MFGM-supplemented, low-energy, low-protein experimental formula (EF) or a standard formula (SF) until 6 mo of age. The energy and protein contents of the EF and SF were 60 and 66 kcal/100 mL and 1.20 and 1.27 g/100 mL, respectively. A breastfed reference (BFR) group consisted of 80 infants.

RESULTS

At 12 mo of age, the cognitive score (mean ± SD) on testing with the Bayley Scales of Infant and Toddler Development, Third Edition, was significantly higher in the EF group than in the SF group (105.8 ± 9.2 compared with 101.8 ± 8.0; P = 0.008) but was not significantly different from that in the BFR group (106.4 ± 9.5; P = 0.73). The EF group ingested larger volumes of formula than did the SF group (864 ± 174 compared with 797 ± 165 mL/d; P = 0.022), fully compensating for the lower energy density. No significant differences in linear growth, weight gain, body mass index, percentage body fat, or head circumference were found between the EF and SF groups.

CONCLUSIONS

MFGM supplementation to infant formula narrows the gap in cognitive development between breastfed and formula-fed infants. Between 2 and 6 mo of age, formula-fed term infants have the capacity to upregulate their ingested volumes when the energy density of formula is reduced from 66 to 60 kcal/100 mL.

Timing training in three children with diplegic cerebral palsy: short- and long-term effects on upper-limb movement organization and functioning

Despite the great need of interventions to maintain and improve motor functions in children with diplegic cerebral palsy (DCP), scientific evaluations of existing training methods are rare. This study aimed to explore individual effects of synchronized metronome training (SMT) on motor timing, spatio-temporal movement organization, and subjective experiences of changes in upper-limb functions in three children with DCP. All children participated in an individualized 4-week/12 session SMT training regime. Measurements before training (Pre), after training (Post1), and at 6 months post completed training (Post2) were made by the applied SMT training equipment, optoelectronic registrations of goal-directed upper-limb movements, and a questionnaire assessing subjective experiences of changes in upper-limb functions and usability. In general, the training regime was shown to have little effect on motor timing. However, some positive changes in spatio-temporal movement organization were found. Two children also reported substantial long-lasting positive changes in subjective experiences of hand/arm functionality in terms of increased movement control and reduced muscle tone. For these children, parallel kinematic findings also indicated smoother and faster movement trajectories that remained at Post2. Although highly individualized, the shown improvements in upper-limb kinematics and subjective experiences of improved functionality of the hands/arms for two of the cases warrant further explorations of SMT outcomes in children with DCP.

Long-term influences of a preterm birth on movement organization and side specialization in children at 4-8 years of age

This study explored upper-limb and head kinematics during unimanual goal-directed movements in children born preterm (PT) and full-term (FT) aged 4-8 years. Further, functional lateralization was investigated through side-specific kinematics and hand preference observations. Altogether, 141 children were included, divided into three sub-groups based on gestation week at birth (GW). Children born FT (38-41 GW) and moderately PT (33-35 GW) showed faster, smoother, and shorter movement trajectories than children born very PT (V-PT < 33 GW). Only children born FT expressed evident side differences that were characterized by smoother movements with the preferred side. Regarding hand preference, the children born V-PT showed increased rates of non-right-handedness compared with the other groups. Regardless of hand preference, the children born V-PT showed less well organized movements compared with the other groups. These findings suggest that spatio-temporal movement organization and side specialization at pre-/early school-age are affected by a PT birth, and more frequently so for children born before 33 GWs, indicating long-lasting influences on neuromotor development and specialization.

Short- and long-term effects of synchronized metronome training in children with hemiplegic cerebral palsy: a two case study

BACKGROUND

Children with cerebral palsy (CP) require individualized long-term management to maintain and improve motor functions. The objective of this study was to explore potential effects of synchronized metronome training (SMT) on movement kinematics in two children diagnosed with spastic hemiplegic CP (HCP).

METHOD

Both children underwent 4-weeks/12 sessions of SMT by means of the Interactive Metronome (IM). Optoelectronic registrations of goal-directed uni- and bimanual upper-limb movements were made at three occasions; pre-training, post completed training and at 6-months post completed training.

RESULTS

Significant changes in kinematic outcomes following IM training were found for both cases. Findings included smoother and shorter movement trajectories in the bimanual condition, especially for the affected side. In the unimanual condition, Case I also showed increased smoothness of the non-affected side.

CONCLUSIONS

The observed short- and long-term effects on the spatio-temporal organization of upper-limb movements need to be corroborated and extended by further case-control studies.

Handedness in preterm born children: a systematic review and a meta-analysis

It has been proposed that left and/or non-right handedness (NRH) is over-represented in children with a history of preterm birth because such births are associated with a greater incidence of insult to the brain. We report an approximate two-fold increase in left and/or non-right handedness based on a systematic search of the literature from 1980 to September 2010 for English-language articles reporting handedness status in preterm children compared with fullterm controls either as a main focus of the study or as a secondary finding. In total, thirty articles met the inclusion criteria. However, there was a great variation between the included studies in terms of objectives, population characteristics, sample size and methodologies used. While the majority of studies reported a higher incidence of NRH in preterm than fullterm children, this was not a consistent finding. A quality assessment was made to explore the differences in overall study quality and handedness assessment methodology between studies. A random-effects model meta-analysis was then performed to estimate the accumulated effect of preterm birth on handedness (18 studies; 1947 cases and 8170 controls). Preterm children displayed a significantly higher occurrence of NRH than fullterm children (odds ratio [OR]: 2.12; 95% confidence interval [CI]: 1.59-2.78). Sources of heterogeneity were investigated by supplementary meta-analyses considering studies with high or low overall and handedness assessment quality. Publication bias was assessed by Egger's test of the intercept and Duvall and Tweedie's trim-and-fill method. The outcomes of these procedures did not jeopardize the overall finding of reliably increased OR for NRH in preterm children. The present review suggests that a preterm birth is indeed associated with a greater than two-fold likelihood of NRH. Several studies also explored the relationship between handedness and neuropsychological functioning (cognition mainly) with an array of methods. Although not without disagreement, this association was found to be concordant. Studying handedness in preterm children, therefore, is a potentially important index of hemispheric organization and cognitive and sensory-motor functions following neurodevelopmental disturbance.

Goal-directed arm movements in children with fetal alcohol syndrome: a kinematic approach

BACKGROUND

Although many studies have documented deficits in general motor functioning in children with fetal alcohol syndrome (FAS), few have employed detailed measurements to explore the specific nature of such disabilities. This pilot study explores whether three-dimensional (3D) kinematic analysis may generate increased knowledge of the effect of intrauterine alcohol exposure on motor control processes by detecting atypical upper-limb movement pattern specificity in children with FAS relative to typically developing (TD) children.

METHODS

Left and right arm and head movements during a sequential unimanual goal-directed precision task in a sample of children with FAS and in TD children were registered by an optoelectronic tracking system (ProReflex, Qualisys Inc.).

RESULTS

Children with FAS demonstrated evidently poorer task performance compared with TD children. Additionally, analyses of arm movement kinematics revealed atypical spatio-temporal organization in the children with FAS. In general, they exhibited longer arm movement trajectories at both the proximal and distal level, faster velocities at the proximal level but slower at the distal level, and more segmented distal movements. Children with FAS also showed atypically augmented and fast head movements during the task performance.

CONCLUSIONS

Findings indicate neuromotor deficits and developmental delay in goal-directed arm movements because of prenatal alcohol exposure. It is suggested that 3D kinematic analysis is a valid technique for furthering the understanding of motor control processes in children with FAS/fetal alcohol spectrum disorders. A combination with relevant neuroimaging techniques in future studies would enable a more clear-cut interpretation of how atypical movement patterns relate to underlying brain abnormalities.

Atypical functional lateralization in children with fetal alcohol syndrome

In order to explore effects of prenatal alcohol exposure on functional lateralization, item tasks measuring preferences of hand, foot, eye, and ear were administered to a sample of 23 children diagnosed with fetal alcohol syndrome (FAS) compared with typically developing (TD) children. In addition, a dichotic listening task was administered to a subsample of 11 children with FAS and a TD group of comparable age, sex and handedness. The children with FAS were characterized by increased nonright-handedness compared with TD children. No differences were evident for preferential use of foot, eye, or ear. Moreover, children with FAS displayed more right ear extinctions during dichotic listening relative to TD children, indicating a lack of right ear advantage. The results add to findings of decreased manual asymmetry and less left-lateralized speech perception in children with developmental disorders, and are further discussed in relation to the high incidence of callosal abnormalities in alcohol-exposed children.

Impairment severity selectively affects the control of proximal and distal components of reaching movements in children with hemiplegic cerebral palsy

This study explored proximal-to-distal components during goal-directed reaching movements in children with mild or moderate hemiplegic cerebral palsy (HCP); [seven females, four males; mean age 8 y 6 mo; SD 27 mo], compared with age-matched, typically developing children (seven females, five males; mean age 8 y 3 mo [SD 25 mo]. Severity of HCP was assessed following the approach of Claeys et al. Optoelectronic registrations were made during unimanual reaching-to-grasp and reaching-to-hit movements with both the affected/non-preferred and unaffected/preferred side. Regardless of task, the children with HCP, particularly those with moderate impairment, displayed less optimal spatiotemporal organization of movements performed with the affected arm. Compared with the goal to hit, and increasingly with more severe impairment, children with HCP adapted to the goal to grasp by recruiting augmented shoulder movements when reaching with the affected side. A resulting impact on distal kinematics was found in shorter, straighter, and less segmented movement paths. Thus, depending on severity of hemispheric lesions and task complexity, unilateral brain injuries in HCP may selectively affect neural pathways underlying both proximal and distal arm movement control. Levels of both ipsi- and contralateral activation in relation to side and lesion severity should be considered in future studies on prehension movements in HCP.

The role of the corpus callosum in the perception of reversible figures in children

To test the role of interhemispheric competition through the corpus callosum in the perceptual alternation of reversible figures, we compared children with callosal pathology and typically developing children on a bistable stimulus task. The children with corpus callosum pathology reported significantly less changes of percepts per minute than the age-matched typically developing children. In addition, older typically developing children reported significantly more changes of percepts than the younger ones. These results support the hypothesis that the rate of reversal between two interpretations of a bistable stimulus may be partly mediated by the corpus callosum.

Functional asymmetries in the stepping response of the human newborn: a kinematic approach

In order to investigate subtle expressions of functional asymmetries in newborn leg movements, kinematic registrations were made on a sample of 40 healthy fullterm newborn infants during performance of the stepping response. Time-position data were collected from markers attached to the hip, knee and ankle joints of the left and right leg, and movements of both legs recorded simultaneously. Findings included evident side differences in terms of smoother trajectories of the right leg as a consequence of less movement segmentation compared to the left leg. Additionally, analyses of intralimb coordination revealed side differences with regard to stronger ankle-knee couplings and smaller phase shifts in the right leg. The findings suggest that asymmetries in newborn stepping responses are present in terms of spatio-temporal parameters and intralimb coordination. No evidence of a lateral preference in terms of frequency of the first foot moved was found. The present study adds new understanding to the lateralized attributes of the stepping response in the human newborn and as such points to new directions of research on the nature of laterality in the future.

Quantitative assessment of right and left reaching movements in infants: A longitudinal study from 6 to 36 months

This longitudinal study aimed to explore the early presence and developmental pattern of laterality in reaching kinematics and its relationship to side use. In order to do so, 3-D kinematic measurements as well as 2-D video recordings of right-left reaching movements were successively carried out for 17 infants at the ages of 6, 9, 12, and 36 months. Additional investigations of hand preference were made at 36 months. As four infants were prematurely born, their outcomes were compared to those of the fullterm participants. While most of the infants in the early ages showed a rather inconsistent preference in terms of frequency and distributions of right-left side use, the analyses of reaching kinematics revealed a more consistent pattern of fewer movements units (MUs) and straighter right-sided reaching for the majority of infants at all tested ages. However, reaching kinematics from the preterm infants were generally more variable and less side consistent. It is proposed that the development of human handedness originates from an early right arm rather than hand preference in that representations of asymmetry in bilateral projections (involved in arm movements) developmentally precede contralateral projections (involved in refined hand/finger movements).

Upper and lower body functional asymmetries in the newborn: do they have the same lateral biases?

It is still an open question as to whether functional asymmetries in the human newborn derive from a single lateralized system or multiple subsystems based on different neural mechanisms. In the present study, asymmetries in head turning were compared to those in leg movements during stepping and placing, with the latter also being related to differences in leg mass. The effects of an active versus an inactive state or condition were examined for all three behaviors. No overall lateral biases were found for head turning or for the first foot to move in stepping and placing, and there were no concordances among them; however, there was an asymmetry in that the left foot had a shorter onset latency when compared to the right foot for both stepping and placing. Findings are discussed in terms of what they imply about underlying neural systems that have a bearing on expressions of newborn laterality, and also with regard to the impact of methodological differences in this area of study.