Pulling to stand: common trajectories and individual differences in development

Harnessing the power of child development records to detect early neurodevelopmental disorders using Bayesian analysis

AIM

This study aims to analyse the developmental data from public health nurses (PHNs) to identify early indicators of neurodevelopmental disorders (NDDs) in young children using Bayesian network (BN) analysis to determine factor combinations that improve diagnosis accuracy.

METHODS

The study cohort was 501 children who underwent health checkups at 18 and 36-month. Data included demographics, pregnancy, delivery, neonatal factors, maternal interviews, and physical and neurological findings. Diagnoses were made by paediatricians and child psychiatrists using standardised tools. Predictive accuracy was assessed by the receiver operating characteristic (ROC) curve analysis.

RESULTS

We identified several infant/toddler factors significantly associated with NDD diagnoses. Predictive factors included meconium-stained amniotic fluid, 1 min Apgar score, and early developmental milestones. ROC curve analysis showed varying predictive accuracies based on evaluation timing. The 10-month checkup was valid for screening but less reliable for excluding low-risk cases. The 18-month evaluation accurately identified children at NDD risk.

CONCLUSION

The study demonstrates the potential of using developmental records for early NDD detection, emphasising early monitoring and intervention for at-risk children. These findings could guide future infant mental health initiatives in the community.

An update of the development of motor behavior

This primer describes research on the development of motor behavior. We focus on infancy when basic action systems are acquired-posture, locomotion, manual actions, and facial actions-and we adopt a developmental systems perspective to understand the causes and consequences of developmental change. Experience facilitates improvements in motor behavior and infants accumulate immense amounts of varied everyday experience with all the basic action systems. At every point in development, perception guides behavior by providing feedback about the results of just prior movements and information about what to do next. Across development, new motor behaviors provide new inputs for perception. Thus, motor development opens up new opportunities for acquiring knowledge and acting on the world, instigating cascades of developmental changes in perceptual, cognitive, and social domains. This article is categorized under: Cognitive Biology > Cognitive Development Psychology > Motor Skill and Performance Neuroscience > Development.

Equifinality in infancy: The many paths to walking

Many different pathways can lead to the same result or developmental outcome. What are the developmental routes that result in the onset of walking? In this longitudinal study, we documented patterns of infant locomotion during everyday activities at home for 30 prewalking infants. Using a milestone-based design, we focused on observations spanning the two months before the onset of walking (M age at walk onset = 11.98 months, SD = 1.27). We examined how much time infants spent in motion and when they moved, whether they were more likely to do so while prone (crawling) or upright with support (cruising or supported walking). Results showed immense variability in infants' practice regimes en route to walking-some infants spent relatively similar amounts of time crawling, cruising, and supported walking at each session, others preferred one method of travel over the alternatives, and some switched between different types of locomotion from session to session. In general, however, infants spent a larger share of their movement time in upright positions compared to prone. Finally, our densely sampled dataset revealed a clear feature of locomotor development: infants follow many distinct and variable paths to walk onset, regardless of the age at which it is attained.

Developing language in a developing body, revisited: The cascading effects of motor development on the acquisition of language

In the first years of life, infants rapidly acquire a series of new motor skills. They learn to sit independently, to walk with skill, and to engage in a wide variety of interactions with objects. Over these same years, infants also begin to develop language. These are not isolated events. In a complex developing system, even small changes in one domain can have far-reaching effects on development in other domains. This is the fundamental idea behind the rich framework known as the developmental cascades perspective. Here we employ this framework to show how early motor advances can exert downstream effects on the development of language. Focusing first on the emergence of independent sitting, then on the development of walking, and finally on changes in the ways in which infants act on and combine actions on objects, we describe how the nature and quality of infant actions change dramatically over the first few years and how this brings with it new possibilities for engaging the environment, more sophisticated ways of interacting with people, and significant alterations in communications directed by caregivers to the infant and coordinated with infant action in time and in meaning. The developmental cascades framework provides an approach for understanding how advances in motor skills influence communicative and language development, and more generally, for conceptualizing the constant, dynamic, and complex interplay between developing infants and their environments as it unfolds over time. This article is categorized under: Linguistics > Language Acquisition Psychology > Motor Skill and Performance Psychology > Development and Aging.

Frontoparietal and default mode network connectivity varies with age and intelligence

Background

Anticorrelated resting state connectivity between task-positive and task-negative networks in adults supports flexible shifting between externally focused attention and internal thought. Findings suggest that children show positive correlations between task-positive (frontoparietal; FP) and task-negative (default mode; DMN) networks. FP-DMN connectivity also associates with intellectual functioning across the lifespan. We investigated whether FP-DMN connectivity in healthy children varied with age and intelligence quotient (IQ).

Methods

We utilized network-based statistics (NBS) to examine resting state functional connectivity between FP and DMN seeds in N = 133 7−25-year-olds (M_age = 15.80). Linear regression evaluated FP-DMN associations with IQ.

Results

We detected NBS subnetworks containing both within- and between-network connections that were inversely associated with age. Four FP-DMN connections showed more negative connectivity between FP (inferior frontal gyrus and precentral gyrus) and DMN regions (frontal medial cortex, precuneus, and frontal pole) among older participants. Frontal pole-precentral gyrus connectivity inversely associated with IQ.

Conclusions

FP-DMN connectivity was more anticorrelated at older ages, potentially indicating dynamic network segregation of these circuits from childhood to early adulthood. Youth with more mature (i.e., anticorrelated) FP-DMN connectivity demonstrated higher IQ. Our findings add to the growing body of literature examining neural network development and its association with IQ.

Development of Locomotor-Related Movements in Early Infancy

This mini-review focuses on the emergence of locomotor-related movements in early infancy. In particular, we consider multiples precursor behaviors of locomotion as a manifestation of the development of the neuronal networks and their link in the establishment of precocious locomotor skills. Despite the large variability of motor behavior observed in human babies, as in animals, afferent information is already processed to shape the behavior to specific situations and environments. Specifically, we argue that the closed-loop interaction between the neural output and the physical dynamics of the mechanical system should be considered to explore the complexity and flexibility of pattern generation in human and animal neonates.

Intentional action processing across the transition to crawling: Does the experience of self-locomotion impact infants' understanding of intentional actions?

Motor developmental milestones in infancy, such as the transition to self-locomotion, have cascading implications for infants' social and cognitive development. The current studies aimed to add to this literature by exploring whether and how crawling experience impacts a key social-cognitive milestone achieved in infancy: the development of intentional action understanding. Study 1 used a cross-sectional, age-held-constant design to examine whether locomotor (n = 36) and prelocomotor (n = 36) infants differ in their ability to process a failed intentional reaching action. Study 2 (n = 124) further probed this question by assessing how variability in locomotor infants' experience maps onto variability in their failed intentional action understanding. Both studies also assessed infants' tendency to engage in triadic interactions to shed light on whether self-locomotion impacts intentional action understanding directly or indirectly via changes in infants' interactions with social partners. Altogether, results showed no evidence for the role of self-locomotion in the development of intentional action understanding. Locomotor and prelocomotor infants did not differ in their failed action understanding or levels of triadic engagement (Study 1) and individual differences in days of crawling experience, propensity to crawl during play, and maximum crawling speed failed to predict infants' intentional action understanding or triadic engagement (Study 2). Explanations for these null findings and alternative influences on the development of intentional action understanding are considered.

Development (of Walking): 15 Suggestions

Although a fundamental goal of developmental science is to identify general processes of change, developmental scientists rarely generalize beyond their specific content domains. As a first step toward a more unified approach to development, we offer 15 suggestions gleaned from a century of research on infant walking. These suggestions collectively address the multi-leveled nature of change processes, cascades of real-time and developmental events, the diversity of developmental trajectories, inter- and intraindividual variability, starting and ending points of development, the natural input for learning, and the roles of body, environment, and sociocultural context. We argue that these 15 suggestions are not limited to motor development, and we encourage researchers to consider them within their own areas of research.

Trajectories of Early Childhood Developmental Skills and Early Adolescent Psychotic Experiences: Findings from the ALSPAC UK Birth Cohort

Objective: The aim of this study was to use prospective data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine association between trajectories of early childhood developmental skills and psychotic experiences (PEs) in early adolescence. Method: This study examined data from n = 6790 children from the ALSPAC cohort who participated in a semi-structured interview to assess PEs at age 12. Child development was measured using parental report at 6, 18, 30, and 42 months of age using a questionnaire of items adapted from the Denver Developmental Screening Test - II. Latent class growth analysis was used to generate trajectories over time for measures of fine and gross motor development, social, and communication skills. Logistic regression was used to investigate associations between developmental trajectories in each of these early developmental domains and PEs at age 12. Results: The results provided evidence that decline rather than enduringly poor social (adjusted OR = 1.28, 95% CI = 1.10-1.92, p = 0.044) and communication skills (adjusted OR 1.12, 95% CI = 1.03-1.22, p = 0.010) is predictive of suspected or definite PEs in early adolescence, than those with stable and/or improving skills. Motor skills did not display the same pattern of association; although gender specific effects provided evidence that only declining pattern of fine motor skills was associated with suspected and definite PEs in males compared to females (interaction OR = 1.47, 95% CI = 1.09-1.97, p = 0.012). Conclusion: Findings suggest that decline rather than persistent impairment in social and communication skills were most predictive of PEs in early adolescence. Findings are discussed in terms of study's strengths, limitations, and clinical implications.

See and be seen: Infant-caregiver social looking during locomotor free play

Face-to-face interaction between infants and their caregivers is a mainstay of developmental research. However, common laboratory paradigms for studying dyadic interaction oversimplify the act of looking at the partner's face by seating infants and caregivers face to face in stationary positions. In less constrained conditions when both partners are freely mobile, infants and caregivers must move their heads and bodies to look at each other. We hypothesized that face looking and mutual gaze for each member of the dyad would decrease with increased motor costs of looking. To test this hypothesis, 12-month-old crawling and walking infants and their parents wore head-mounted eye trackers to record eye movements of each member of the dyad during locomotor free play in a large toy-filled playroom. Findings revealed that increased motor costs decreased face looking and mutual gaze: Each partner looked less at the other's face when their own posture or the other's posture required more motor effort to gain visual access to the other's face. Caregivers mirrored infants' posture by spending more time down on the ground when infants were prone, perhaps to facilitate face looking. Infants looked more at toys than at their caregiver's face, but caregivers looked at their infant's face and at toys in equal amounts. Furthermore, infants looked less at toys and faces compared to studies that used stationary tasks, suggesting that the attentional demands differ in an unconstrained locomotor task. Taken together, findings indicate that ever-changing motor constraints affect real-life social looking.

Infant motor activity during sleep: Simultaneous use of two actigraphs comparing right and left legs

Motor asymmetry during the first hours of sleep documented in adults found higher activity in the non-dominant limb. The stage of development at which such asymmetries first appear is unknown. Twenty healthy infants were followed from 7 to 12months of age, at 3-week intervals, comparing motor activity of the right and left legs during sleep using twin actigraphs (AMI). Hour-by-hour analysis of the first seven hours of nocturnal sleep found no consistent difference in activity levels between the right and left legs. Using the standard algorithm for infants, which provides an overall estimate of sleep quality, revealed discrepancies in night waking episodes (Right versus Left) in 33% of the nights. Results pertaining to leg movement suggest that motor asymmetry is not yet present during the first year of life. However, given the large discrepancies in the detection of night waking, further investigation of the developmental course of circadian motor asymmetry is warranted.

The development of motor behavior

This article reviews research on the development of motor behavior from a developmental systems perspective. We focus on infancy when basic action systems are acquired. Posture provides a stable base for locomotion, manual actions, and facial actions. Experience facilitates improvements in motor behavior and infants accumulate immense amounts of experience with all of their basic action systems. At every point in development, perception guides motor behavior by providing feedback about the results of just prior movements and information about what to do next. Reciprocally, the development of motor behavior provides fodder for perception. More generally, motor development brings about new opportunities for acquiring knowledge about the world, and burgeoning motor skills can instigate cascades of developmental changes in perceptual, cognitive, and social domains. WIREs Cogn Sci 2017, 8:e1430. doi: 10.1002/wcs.1430 For further resources related to this article, please visit the WIREs website.

Sleep disruption and motor development: Does pulling-to-stand impacts sleep-wake regulation?

During the second half of the 1st year, periods of increased sleep disruption have been documented alongside overall improvement in sleep-wake regulation. The objective of the present research was to test if pulling-to-stand (PTS), a milestone typically achieved during the latter part of the 1st year, co-occurs with a period of disrupted sleep. In a longitudinal design, 20 healthy infants were followed-up, from 7 to 11-12 months, at 3-week intervals. Each measurement consisted of filmed motor observations and sleep recordings (actigraphy), both conducted at home. It was found that among early achievers of PTS (by 8 months), the milestone was time-linked to a period of disrupted sleep. The results point to the significance of timing in the interplay between domains of development, and highlight the importance of considering both chronological and developmental metrics in studying changes in sleep-wake regulation.

Asymmetrical motor behaviour as a window to early leg preference: a longitudinal study in infants 7-12 months of age

This longitudinal study explored leg preference in infancy during half-kneel pulling-to-stand (PTS) and asymmetrical four-point kneeling, which is part of the typical motor repertoire of infants. The special characteristics of the half-kneel PTS as a discrete task, performed in a bilateral context provide the opportunity to explore leg preference during an asymmetrical behaviour. Twenty-seven infants were observed in their homes, every 3 weeks between the ages of 7-12 months. Leg preference was determined by the "lead-out" limb used as the infants pulled to stand from the half-kneeling position (half-kneel PTS). As a complementary measure, the leading leg during asymmetrical four-point kneeling and crawling ("asymmetrical four-point patterns") was used in the 10 infants who developed these patterns. The infants studied showed a general preference for using a leading leg during half-kneel PTS, which was mostly consistent over the study period. A strong correlation was found between leg preferences during half-kneel PTS and asymmetrical four-point patterns. The findings documented functional asymmetry in infant lower limbs during half-kneel PTS and asymmetrical four-point patterns, highlighting the importance of the tasks used to define leg preference.

Individual differences in learning a novel discrete motor task

Many motor learning studies focus on average performance while it is known from everyday life experience that humans differ in their way of learning new motor tasks. This study emphasises the importance of recognizing individual differences in motor learning. We studied individual tool grasping profiles of individuals who learned to pick up objects with a novel tool, a pair of pliers. The pair of pliers was attached to the thumb and the index finger so that the tip of the thumb and the tip of the index finger were displaced to the beaks of the pair of pliers. The grasp component was manipulated by varying the location of the hinge of the pair of pliers, which resulted in different relations between beak opening and closing and finger opening and closing. The Wider Beak group had the hinge at 7 cm, the Same Beak group had the hinge at 10 cm (i.e., in the middle), and the Smaller Beak group had the hinge at 13 cm from the digits. Each group consisted of ten right-handed participants who picked up an object with one of the pairs of pliers 200 times on two subsequent days. Hand opening, plateau phase, hand closing, grasping time and maximum aperture were analyzed. To characterize individual changes over practice time, a log function was fitted on these dependent variables and the ratio of improvement was determined. Results showed that at the beginning stage of tool use learning the characteristic grasping profile consisted of three phases; hand opening, plateau phase and hand closing. Over practicing individual participants differed in the number of phases that changed, the amount of change in a phase and/or the direction of change. Moreover, with different pliers different learning paths were found. The importance of recognizing individual differences in motor learning is discussed.

What Cruising Infants Understand about Support for Locomotion

"Cruising" infants can only walk using external support to augment their balance. We examined cruisers' understanding of support for upright locomotion under four conditions: cruising over a wooden handrail at chest height, a large gap in the handrail, a wobbly unstable handrail, and an ill positioned low handrail. Infants distinguished among the support properties of the handrails with differential attempts to cruise and handrail-specific forms of haptic exploration and gait modifications. They consistently attempted the wood handrail, rarely attempted the gap, and occasionally attempted the low and wobbly handrails. On the wood and gap handrails, attempt rates matched the probability of cruising successfully; but on the low and wobbly handrails, attempt rates under- and over-estimated the probability of success, respectively. Haptic exploration was most frequent and varied on the wobbly handrail, and gait modifications-including previously undocumented "knee cruising"-were most frequent and effective on the low handrail. Results are discussed in terms of developmental changes in the meaning of support.