Postural complexity differs between infant born full term and preterm during the development of early behaviors

Assessing Postural Control From Birth to Adulthood Among Individuals Born Preterm: A Systematic Review

Premature life exposure, meaning an immature central nervous system, presents a significant challenge for the development of postural control and, in turn, overall motor development. Preventing motor delay thus requires identifying, characterizing, and quantifying deficit in postural control as early as possible. In our study, we reviewed the procedures used in past studies to assess postural control among individuals born preterm, specifically the characterization of participants, the instruments and motor tasks involved, the types of data collected and analyzed, and the outcomes. To that end, we performed a literature search on PubMed, Wiley Online Library, Web of Science, and Scopus using Boolean logic and assessed the quality of the studies with a standardized assessment based on the Strengthening the Reporting of Observational Studies in Epidemiology guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. Of 35 potential studies, 24 were included; all evaluated infants born preterm, but six did not include a control group of full-term infants. Although the heterogeneity of measurements, variability of instruments, and divergence in motor tasks examined limit definitive conclusions based on quantitative synthesis and the generalization of the results, most studies revealed dysfunctional postural control among individuals born preterm.

Association between environmental factors during the COVID-19 pandemic and functioning of infants with biological risk in the first year of life: Cross-sectional exploratory study

BACKGROUND

Child development can be influenced by family and environmental factors, which changed during the COVID-19 pandemic. Thus, it is important to explore how these factors are associated with the functioning of infants with biological risk in the first year of life.

OBJECTIVE

This study aimed to investigate associations between family factors, home opportunities, caregiver perception of environmental support and barriers at home and environmental factors during the COVID-19 pandemic and gross motor skills and home participation in infants with biological risk in the first year of life.

METHODS

Fifty-six infants aged two to 12 months (M = 5.80 months; ±2.44) and their mothers performed remote assessments of gross motor skills using the Alberta Infant Motor Scale (AIMS); participation and environment (phone call) by the Young Children's Participation and Environment Measure (YC-PEM); family factors (income, age and maternal education), home opportunities - The Affordances in the Home Environment for Motor Development - Infant Scale (AHEMD-IS) and environmental factors during the COVID-19 pandemic (social distancing, emotional and financial factors and physiotherapy) (online forms). Regression models were constructed, considering gross motor skills and home participation as outcome variables, with a 5 % significance level.

RESULTS

We found that older maternal age (p = 0.001), more home opportunities (p = 0.043), and less rigorous social distancing (as opposed to total social distancing [p = 0.045]) were significantly associated with better gross motor skills; and higher maternal education (p = 0.050) was associated with more involvement in home activities.

CONCLUSION

Family factors, home opportunities and social distancing were differently associated with the gross motor skills and home participation of infants with biological risk in the first year of life.

Using the center of pressure movement analysis in evaluating spontaneous movements in infants: a comparative study with general movements assessment

BACKGROUND

Researchers have attempted to automate the spontaneous movement assessment and have sought quantitative and objective methods over the past decade. The purpose of the study was to present a quantitative assessment method of spontaneous movement using center-of-pressure (COP) movement analysis.

METHODS

A total of 101 infants were included in the study. The infants were placed in the supine position on the force plate with the cranial-caudal orientation. In this position, the recording of video and COP movement data were made simultaneously for 3 min. Video recordings were used to observe global and detailed general movement assessment (GMA), and COP time series data were used to obtain quantitative movement parameters.

RESULTS

According to the global GMA, 13 infants displayed absent fidgety movements (FMs) and 88 infants displayed normal FMs. The binary logistic regression model indicated significant association between global GMA and COP movement parameters (chi-square = 20.817, p < 0.001). The sensitivity, specificity, and overall accuracy of this model were 85% (95% CI: 55-98), 83% (95% CI: 73-90), and 83% (95% CI: 74-90), respectively. The multiple linear regression model showed a significant association between detailed GMA (motor optimality score-revised/MOS-R) and COP movement parameters (F = 10.349, p < 0.001). The MOS-R total score was predicted with a standard error of approximately 1.8 points (6%).

CONCLUSIONS

The present study demonstrated the possible avenues for using COP movement analysis to objectively detect the absent FMs and MOS-R total score in clinical settings. Although the method presented in this study requires further validation, it may complement observational GMA and be clinically useful for infant screening purposes, particularly in clinical settings where access to expertise in observational GMA is not available.

Postural Control Measurements to Predict Future Motor Impairment in Preterm Infants: A Systematic Review

Preterm infants are more likely to demonstrate developmental delays than fullterm infants. Postural measurement tools may be effective in measuring the center of pressure (COP) and asymmetry, as well as predicting future motor impairment. The objective of this systematic review was to evaluate existing evidence regarding use of pressure mats or force plates for measuring COP and asymmetry in preterm infants, to determine how measures differ between preterm and fullterm infants and if these tools appropriately predict future motor impairment. The consulted databases included PubMed, Embase, Scopus, and CINAHL. The quality of the literature and the risk of bias were assessed utilizing the ROB2: revised Cochrane risk-of bias tool. Nine manuscripts met the criteria for review. The postural control tools included were FSA UltraThin seat mat, Conformat Pressure-Sensitive mat, Play and Neuro-Developmental Assessment, and standard force plates. Studies demonstrated that all tools were capable of COP assessment in preterm infants and support the association between the observation of reduced postural complexity prior to the observation of midline head control as an indicator of future motor delay. Postural measurement tools provide quick and objective measures of postural control and asymmetry. Based on the degree of impairment, these tools may provide an alternative to standardized assessments that may be taxing to the preterm infant, inaccessible to therapists, or not sensitive enough to capture motor delays.

Biological and environmental factors may affect children's executive function through motor and sensorimotor development: Preterm birth and cerebral palsy

Disruptive biological and environmental factors may undermine the development of children's motor and sensorimotor skills. Since the development of cognitive skills, including executive function, is grounded in early motor and sensorimotor experiences, early delays or impairments in motor and sensorimotor processing often trigger dynamic developmental cascades that lead to suboptimal executive function outcomes. The purpose of this perspective paper is to link early differences in motor/sensorimotor processing to the development of executive function in children born preterm or with cerebral palsy. Uncovering such links in clinical populations would improve our understanding of developmental pathways and key motor and sensorimotor skills that are antecedent and foundational for the development of executive function. This knowledge will allow the refinement of early interventions targeting motor and sensorimotor skills with the goal of proactively improving executive function outcomes in at-risk populations.

Reliability and Repeatability of a Postural Control Test for Preterm Infants

BACKGROUND

the current study aims to evaluate the reliability and repeatability of a new PT based on Center of Pressure (CoP) movement analysis in a repeated measures design.

METHODS

the examination consisted of two parts: (1) the videotaping of General Movements (GMs) and GMs assessment (GMA) and (2) Posturometric Tests (PT) in supine and prone positions. PTs were performed twice (by two investigators) in the supine and prone positions using a force plate. Based on the GMA results, infants were stratified into two groups: (1) infants with normal FMs (indicating normal future motor outcomes) (n = 18) and (2) infants with abnormal FMs (indicating later neurological dysfunction) (n = 19).

RESULTS

the comparative analysis between the groups of infants with normal FMs and abnormal FMs in PT in supine showed significant differences for all parameters that described spontaneous CoP displacement. The reliability analysis determined that all ICCs of the outcomes presented at least a moderate level of reliability. The ICCs were higher for outcomes of PT performed in the supine position than in the prone position. The ICCs were higher for outcomes of PT performed in infants with abnormal vs. normal FMs.

CONCLUSIONS

although the current study yielded promising results, further longitudinal research in preterm infants should identify whether altered postural control parameters prognose future motor outcomes.

Design and Construct Validity of a Postural Control Test for Pre-Term Infants

A review of the literature indicated that the greatest prognostic value for predicting motor impairment in high-risk infants is the absence of fidgety movements (FMs) at 3 months of post-term age. The purpose of the present study was to characterize a new posturometric test (PT) based on a center-of-pressure (CoP) movement analysis, in terms of design and construct validity, for the detection of postural control disturbances in pre-term infants. The comparative studies were carried out between pre-term infants who presented normal FMs (18 participants) and infants with absent FMs (19 participants), which consisted of the analysis of the CoP trajectory and CoP area in supine and prone positions using the force platform. New PT was performed simultaneously with GMs recorded using a force platform. Statistical analyses revealed significant differences between the groups of infants who presented absent FMs and normal FMs for almost all CoP parameters describing spontaneous sway in the supine position. Based on these preliminary results, it can be concluded, that the application of PT based on the analysis of CoP trajectory, area, and velocity in the supine position has been demonstrated to be valid for the detection of postural control disturbances in pre-term infants.

Outcomes and Hand Use of Reaching Attempts: Comparison of Infants at Risk for Developmental Disability and Infants With Typical Development

Background

Infants at risk for developmental disabilities often show signs of motor delay. Reaching is a skill that can help us identify atypical motor trajectories in early infancy. Researchers have studied performance after onset of reaching, but none have followed infants at risk from pre-reaching to skilled reaching.

Aims

We assessed differences in reaching outcomes and hand use as reaching skill emerged in infants at risk for developmental disabilities and with typical development.

Methods and Procedures

We followed infants at risk for developmental disabilities (n = 11) and infants with typical development (n = 21) longitudinally as they developed reaching skill. Infants reached for a toy at midline while sitting in the caregiver's lap. Video data were coded for reach outcome (miss, touch, partial grasp, and whole-hand grasp) and hand use (right, left, and bilateral).

Outcomes and Results

Infants at risk had a larger proportion of missed reaches across visits compared to infants with typical development. Infants at risk also showed less variability in hand use when grasping over the study period.

Conclusion and Implications

Our results provide information to support early differences in reaching performance to inform identification of typical and atypical developmental trajectories. Future studies should assess how the missed reaches are different and consider other quantitative measures of movement variability in infants at risk.

Gait performance in toddlers born preterm: A sensor based quantitative characterization

BACKGROUND AND OBJECTIVES

Preterm children have an increased risk of motor difficulties. Gait analysis and wearable technologies allow the assessment of motor performance in toddlers, identifying early deviations from typical development. Using a sensor-based approach, gait performance of full-term and preterm toddlers at different risk of motor delay was analysed. The aim was to measure quantitative differences among groups.

METHODS

Twenty-nine two-year old children born preterm (≤36 gestational weeks) and 17 full-term controls, matched for age and walking experience, participated in the study. Preterm children were further divided based on risk of motor delay: preterm at high risk (n = 8, born at ≤28 gestational weeks or with ≤1000 g of body weight), and at moderate risk (n = 21). Children were asked to walk along a corridor while wearing 3 inertial sensors on the lower back and on the ankles. Gait temporal parameters, their variability, and nonlinear metrics of trunk kinematics (i.e. recurrence quantification analysis, multiscale entropy) were extracted from the collected data and compared among groups.

RESULTS

Children born preterm showed significantly longer stance and double support phases, higher variability of temporal parameters, and lower multiscale entropy values than peers born full-term. No difference was found for the other parameters when comparing preterm and full-term children. When comparing children grouped according to risk of delay, with increasing risk, children showed longer stride-, stance- and double-support-time, higher variability of temporal parameters, higher recurrence- and lower multiscale entropy values.

CONCLUSIONS

Sensor-based gait analysis allowed differentiating the gait performance of preterm from full-term toddlers, and of preterm toddlers at different risk of motor delay. When analysing the present results with respect to the expected trajectory of locomotor development, children born preterm, in particular those at higher risk of motor delay, exhibited a less mature motor control performance during gait: lower stability (i.e. longer support phases), and higher variability, although not structured towards the exploration of more complex movements (i.e. higher recurrence- and lower multiscale entropy values). These indexes can serve as biomarkers for monitoring locomotor development and early detecting risk to develop persistent motor impairments.

Infants at risk for physical disability may be identified by measures of postural control in supine

BACKGROUND

Early detection of delay or impairment in motor function is important to guide clinical management and inform prognosis during a critical window for the development of motor control in children. The purpose of this study was to investigate the ability of biomechanical measures of early postural control to distinguish infants with future impairment in motor control from their typically developing peers.

METHODS

We recorded postural control from infants lying in supine in several conditions. We compared various center of pressure metrics between infants grouped by birth status (preterm and full term) and by future motor outcome (impaired motor control and typical motor control).

RESULTS

One of the seven postural control metrics-path length-was consistently different between groups for both group classifications and for the majority of conditions.

CONCLUSIONS

Quantitative measures of early spontaneous infant movement may have promise to distinguish early in life between infants who are at risk for motor impairment or physical disability and those who will demonstrate typical motor control. Our observation that center of pressure path length may be a potential early marker of postural instability and motor control impairment needs further confirmation and further investigation to elucidate the responsible neuromotor mechanisms.

IMPACT

The key message of this article is that quantitative measures of infant postural control in supine may have promise to distinguish between infants who will demonstrate future motor impairment and those who will demonstrate typical motor control. One of seven postural control metrics-path length-was consistently different between groups. This metric may be an early marker of postural instability in infants at risk for physical disability.

Physiotherapy interventions for head and trunk control in children with developmental disabilities: A scoping review protocol

Background: Head and trunk control is prerequisite skill that maximizes engagement and participation in one's environment by integrating vision, oromotor skill, arm control and respiration. Various physiotherapy and technology-based interventions have been utilized to facilitate head and trunk control in children with developmental disabilities. This scoping review is planned to map and summarize existing studies from the scientific literature on physiotherapy and technology-based interventions for head and trunk control in children with developmental disabilities. Methods: The scoping review will utilize the Joanna Briggs Institute scoping review methodology. The review will cover studies including children and adolescents aged between six months and 17 years 11 months 29 days, with developmental disabilities where in child finds difficulty in lifting its head and aligning head and trunk. We will include randomized controlled trial (RCT), non-RCT, quasi-experimental trial, and systematic reviews that have employed physiotherapy and technology-based interventions. Database-specific search strategy will be used to search records in Medline (PubMed and Web of Science), Embase, Scopus, CINAHL, PEDro, and Cochrane Library. Additionally, various grey literatures and clinical-trial registries will be searched. Two reviewers, independently, will screen and extract the data. Tables and visual representations will be utilized to present the extracted data. Registration details: The protocol has been registered in Open Science Framework, DOI:  10.17605/OSF.IO/B3RSU (22 ^nd August 2022).

The influence between gestational age and postural control, a systematic review

The central nervous system (CNS) of preterm infants might have some peculiarities which distinguish it from that of full term infants. The difficulties associated with prematurity are the main cause of deaths all over the world during the new-born period after community-acquired pneumonia, and the second cause of deaths worldwide in children under five years old. Early recognition of signs indicating fragile postural control in premature infants can support understanding and help prevent and early intervention on possible future neuromotor dysfunctions in these subjects. The purpose of this paper is to determine if there is a qualitatively different development of postural control in premature infants without neurological involvement and infants born at term. We conducted a systematic review of longitudinal and cross-sectional case-control studies published between 2010 and March 2020 on this topic. The evaluation of parameters related to postural control was also included. The methodological quality of the selected works was evaluated using the CASPe critical reading programme for cases and controls. PRISMA guidelines for systematic reviews were followed for prematurity and postural control. 16 articles were included. The total sample amounted to 3,460 participants, of which 1,860 in the preterm group, and 1,600 in the control group. All the studies found show a poorer postural control by the group of children born preterm compared to the group of children born at term and one study indicating more limited postural control with higher prematurity. Regarding the methodological quality according to CASPe, those studies exceeding half of the total score were considered of adequate quality.

Does late preterm birth impact trunk control and early reaching behavior?

The aims of the study were to 1) verify the level of trunk control longitudinally and reaching behavior while sitting in two positions in late preterm (LPT) and full-term (FT) infants, 2) determine whether the level of trunk control relates to reaching outcomes. Twenty LPT infants and 36 infants born FT were assessed via three in-lab visits: at 6, 7, and 8 months. At each visit, the Segmental Assessment of Trunk Control (SATCo) and reaching assessment were performed, where the infants were positioned sitting in the ring and at 90° of flexion of hips, knees, and ankles. Accurate manual support to the trunk was provided in each visit. LPT infants presented a lower level of trunk control over time. LPT infants presented a higher percentage of unimanual reaches and successful grasping at 7 months' visit, and a higher number of reaches at 8 months' visit compared to FT infants. The sitting positions did not influence reaching performance. The level of trunk control relates to functional reaching strategies only in FT infants. This study might provide insights for clinicians for understanding the level of trunk control, the importance of reaching behaviors for exploration, and considering these behaviors as strategies for intervention.

Differences in coordination and timing of pre-reaching upper extremity movements may be an indicator of cerebral palsy in infants with stroke: A preliminary investigation

BACKGROUND

Neonatal stroke is a leading cause of hemiplegic cerebral palsy that occurs around the time of birth. Infants are diagnosed with cerebral palsy when motor impairments become clinically apparent, months or years after the stroke. Tools/methods for identifying high risk or diagnosis of cerebral palsy in infancy are improving.

METHODS

We measured spatial and temporal kinematics of pre-reaching upper extremity movements in 2-3 month old infants with neonatal stroke and typical development. We aimed to evaluate the feasibility of applying kinematics in this population and collect preliminary data to explore (1) if asymmetries are present in the infants with neonatal stroke, particularly those with a later diagnosis of cerebral palsy, and (2) to compare differences in the timing and coordination of their movements to infants with typical development, and infants with stroke and no cerebral palsy. Participants were 21 full-term infants, 10 with stroke (4 who later received a cerebral palsy diagnosis) age 72.1 (SD 9.3) days, and 11 typically developing, age 74.3 (SD 9.3) days.

FINDINGS

Results showed that infants with stroke and cerebral palsy demonstrated significant asymmetry in the average movement length (p = 0.0089) and hand path length (p = 0.0275) between their involved and uninvolved sides and moved less frequently (p = 0.09) and slower (p = 0.041) than infants with stroke and no cerebral palsy.

INTERPRETATION

Results suggest that kinematic analysis might detect asymmetries and motor impairment indicative of hemiplegic cerebral palsy earlier than current assessments and that asymmetry in speed, length and frequency of arm movements may be early indicators. This study is preliminary, limiting interpretation of the results.

Linear and Nonlinear Measures of Postural Control in a Toddler With Cerebral Palsy: Brief Report

PURPOSE

The purpose of this study was to describe changes in linear and nonlinear measures of postural control along with motor outcomes in a young child with cerebral palsy.

SUMMARY OF KEY POINTS

Posturography in sitting and standing, the Gross Motor Function Measure-66 (GMFM-66), and the Early Clinical Assessment of Balance (ECAB) were performed prior to, during, and after physical therapy. The child demonstrated independent sitting throughout the study and developed independent standing during the study. He made improvements in the GMFM-66 and ECAB throughout the study. Higher average values were found in all linear and nonlinear measures in standing when compared to sitting, which may indicate less predictable movement due to less experience with standing.

RECOMMENDATIONS FOR CLINICAL PRACTICE

Greater variability and lower predictability in postural control likely reflect early stages of skill acquisition. Research is needed to understand the optimal levels of movement variability and predictability.

The Head Control Scale: Development, inter-rater reliability, and utility

PURPOSE

This study introduces a new scale for the assessment of head control called the Head Control Scale (HCS). The purpose of this study was to establish interrater reliability of the HCS and to determine its usefulness in a clinical setting.

METHODS

The HCS assesses head control in four positions (prone, supine, pull to sit, and supported sitting) on a 0-4 rating scale. The authors used both a focus group and pilot testing to refine the scale to its final version, which was then used to assess interrater reliability. Twenty-six therapists used the HCS to evaluate head control of five subjects of varying ages and abilities who were videotaped spending 30-40 seconds in each position. Participants also completed a post-rating survey.

RESULTS

Fleiss's weighted kappa coefficient is excellent for the prone (0.82), pull to sit (0.83), and sitting (0.88) positions as well as for the scale overall (kappa = 0.91). It can be described as fair to good for supine (kappa = 0.68).

CONCLUSIONS

The HCS has high interrater reliability and users report it to be a needed tool, applicable to clinical practice, and easy to use.

IMPLICATIONS

The results of this study indicate that the HCS has great potential for clinical use.

Shifting of the body center of gravity in low-risk preterm infants: A video-pedoscope study

AIM

To evaluate whether there is any developmental course of the shifting of the center of gravity (COG) in healthy preterm infants.

METHODS

Eleven healthy preterm infants were assessed on a computerized pedoscope from early preterm to term age. Data from the pedoscope and the videorecorder were analyzed with a special software for the assessment of the COG shifting. Infants were placed on the pedoscope in supine position for 5 min. We scored the positions of the COG during its shifting, the body parts most frequently involved in its shifting and the shifting' amplitude at each epoch. We scored the frequency of the COG shifting in head, trunk and bottom, its direction and amplitude using a semi-quantitative scale.

RESULTS

A developmental course of the COG shifting from preterm throughout post-term ages was demonstrated, with COG position displaced from head to bottom. The shifting amplitude decreased with increasing age. Lateral shifting were never observed.

INTERPRETATION

The developmental course of the COG shifting suggests the maturation of postural behaviour in healthy preterm infants. The displacement of the COG from head to bottom and the reduced amplitude of the COG shifting from preterm to post-term age indicates a more stable body position.

Spatial and temporal postural analysis in children born prematurely

The aim of this study was to compare postural stability in a group of preterm-born children aged 4-6 years old and in a group of age-matched full-term control children by exploring both spatial and temporal analysis of the Center of Pressure (CoP). Twenty-nine children born prematurely (mean age: 5.38±0.17) and twenty-nine age-matched full-term control children participated in this study. Postural control was tested on both a stable and an unstable platform (from Framiral^®) in three different visual conditions: eyes open fixating a target, eyes closed, and with vision perturbed by optokinetic stimulation. We observed a significant increase of both surface area and mean velocity of the CoP in pre-term children compared to full-term control children, particularly in an unstable postural condition. The spectral power indices increased significantly in pre-term children with respect to full-term control children, while the cancelling time was not different between the two groups of children tested. We suggested that poor postural stability observed in preterm children could be due to immaturity of the cortical processes (the occipital parietal prefrontal cortex) involved in motor control. Preterm children could have an inappropriate compensation of sensory inputs when they are tested in difficult postural and/or visual conditions.

Effect of Biomechanical Constraints on Neural Control of Head Stability in Children With Moderate to Severe Cerebral Palsy

BACKGROUND

External support has been viewed as an important biomechanical constraint for children with deficits in postural control. Nonlinear analysis of head stability may be helpful to confirm benefits of interaction between external trunk support and level of trunk control.

OBJECTIVE

The purpose of this study was to compare the effect of biomechanical constraints (trunk support) on neural control of head stability during development of trunk control.

DESIGN

This was a quasi-experimental repeated-measures study.

METHODS

Data from 15 children (4-16 years of age) with moderate (Gross Motor Function Classification System [GMFCS] IV; n=8 [4 boys, 4 girls]) or severe (GMFCS V; n=7 [4 boys, 3 girls]) cerebral palsy (CP) were compared with previous longitudinal data from infants with typical development (TD) (3-9 months of age). Kinematic data were used to document head sway with external support at 4 levels (axillae, midrib, waist, and hip). Complexity, predictability, and active degrees of freedom for both anterior-posterior and medial-lateral directions were assessed.

RESULTS

Irrespective of level of support, CP groups had lower complexity, increased predictability, and greater degrees of freedom. The effect of support differed based on the child's segmental level of control. The GMFCS V and youngest TD groups demonstrated better head control, with increased complexity and decreased predictability, with higher levels of support. The GMFCS IV group had the opposite effect, showing decreased predictability and increased complexity and degrees of freedom with lower levels of support.

LIMITATIONS

Infants with typical development and children with CP were compared based on similar segmental levels of trunk control; however, it is acknowledged that the groups differed for age, cognitive level, and motor experience.

CONCLUSIONS

The effect of external support varied depending on the child's level of control and diagnostic status. Children with GMFCS V and young infants with TD had better outcomes with external support, but external support was not enough to completely correct for the influence of CP. Children with GMFCS IV performed worse, with increased predictability and decreased complexity, when support was at the axillae or midribs, suggesting that too much support can interfere with postural sway quality.

A change in temporal organization of fidgety movements during the fidgety movement period is common among high risk infants

AIM

General movement assessment (GMA) at 9-20 weeks post-term, can effectively predict cerebral palsy. Our aim was to evaluate intra-individual variability of the temporal organization of fidgety movements (FMs) in high risk infants.

MATERIAL AND METHODS

104 High risk infants (66 males) with at least two video recordings from the FMs period participated. 45 of the infants had GA <28 weeks and/or BW ≤800 g. Mean post-term age at first and second assessments was 11.0 (8-16) and 14.0 (11-17) weeks, respectively, and median time-difference between the assessments was 2.0 (range: three days to six weeks) weeks. Video recordings were analyzed according to Prechtl's GMA.

RESULTS

33 (32%) Infants were classified differently at first and second assessments. Six infants (6%) changed from normal to abnormal, and 10 (10%) changed from abnormal to normal FMs. Seven of the ten who changed classification from abnormal to normal were born before GA 26 weeks. A change between intermittent and continual, which are both considered normal, was observed in 17 (16%) infants.

CONCLUSION

A change in temporal organization of FMs is common in high risk infants. Especially in extremely preterm infants with abnormal FMs, more than one assessment should be performed before long-term prognosis is considered.

Infant born preterm have delayed development of adaptive postural control in the first 5 months of life

Infants born preterm are at increased risk of developmental disabilities, that may be attributed to their early experiences and ability to learn. The purpose of this paper was to evaluate the ability of infants born preterm to adapt their postural control to changing task demands.

METHODS

This study included 18 infants born at 32 weeks of gestation or less whose posture was compared in supine under 2 conditions, with and without a visual stimulus presented. The postural variability, measured with root mean squared displacement of the center of pressure, and postural complexity, measured with the approximate entropy of the center of pressure displacement were measured longitudinally from 2.5 to 5 months of age.

RESULTS AND DISCUSSION

The infants looked at the toys in midline for several months prior to adapting their postural variability in a manner similar to full term infants. Only after postural variability was reduced in both the caudal cephalic and medial lateral direction in the toy condition did the infants learn to reach for the toy. Postural complexity did not vary between conditions. These findings suggest that infants used a variety of strategies to control their posture. In contrast to research with infants born full term, the infants born preterm in this study did not identify the successful strategy of reducing movement of the center of pressure until months after showing interest in the toy. This delayed adaptation may impact the infants ability to learn over time.

Deficits in vision and visual attention associated with motor performance of very preterm/very low birth weight children

AIM

To extend understanding of impaired motor functioning of very preterm (VP)/very low birth weight (VLBW) children by investigating its relationship with visual attention, visual and visual-motor functioning.

METHODS

Motor functioning (Movement Assessment Battery for Children, MABC-2; Manual Dexterity, Aiming & Catching, and Balance component), as well as visual attention (attention network and visual search tests), vision (oculomotor, visual sensory and perceptive functioning), visual-motor integration (Beery Visual Motor Integration), and neurological status (Touwen examination) were comprehensively assessed in a sample of 106 5.5-year-old VP/VLBW children. Stepwise linear regression analyses were conducted to investigate multivariate associations between deficits in visual attention, oculomotor, visual sensory, perceptive and visual-motor integration functioning, abnormal neurological status, neonatal risk factors, and MABC-2 scores.

RESULTS

Abnormal MABC-2 Total or component scores occurred in 23-36% of VP/VLBW children. Visual and visual-motor functioning accounted for 9-11% of variance in MABC-2 Total, Manual Dexterity and Balance scores. Visual perceptive deficits only were associated with Aiming & Catching. Abnormal neurological status accounted for an additional 19-30% of variance in MABC-2 Total, Manual Dexterity and Balance scores, and 5% of variance in Aiming & Catching, and neonatal risk factors for 3-6% of variance in MABC-2 Total, Manual Dexterity and Balance scores.

CONCLUSION

Motor functioning is weakly associated with visual and visual-motor integration deficits and moderately associated with abnormal neurological status, indicating that motor performance reflects long term vulnerability following very preterm birth, and that visual deficits are of minor importance in understanding motor functioning of VP/VLBW children.

Postural variability and sensorimotor development in infancy

Infants develop skills through a coupling between their sensory and motor systems. Newborn infants must interpret sensory information and use it to modify movements and organize the postural control system based on the task demands. This paper starts with a brief review of evidence on the use of sensory information in the first months of life, and describes the importance of movement variability and postural control in infancy. This introduction is followed by a review of the evidence for the interactions between the sensory, motor, and postural control systems in typically development infants. The paper highlights the ability of young infants to use sensory information to modify motor behaviors and learn from their experiences. Last, the paper highlights evidence of atypical use of sensory, motor, and postural control in the first months of life in infants who were born preterm, with neonatal brain injury or later diagnosed with cerebral palsy (CP).

Physical activity level is impaired and diet dependent in preterm newborn pigs

BACKGROUND

Preterm infants show delayed development of motor function after birth. This may relate to functional immaturity of many organs, including the gut and brain. Using pigs as model for preterm infants, we hypothesized that early initiation of enteral feeding stimulates both gut growth and neonatal physical activity.

METHODS

In experiment 1, preterm and term pigs were fed parenteral nutrition (PN) or PN plus bovine colostrum (BC, 16-64 ml/kg/d enterally) for 5 d. In experiment 2, preterm pigs were fed PN+BC or PN+formula for 5 d. In experiment 3, preterm pigs were fed BC, formula, or human milk (HM) for 10 d. Incubator home cage activity (HCA) was quantified by continuous camera recordings.

RESULTS

Preterm birth was associated with reduced intestinal weight and HCA (experiment 1), and BC or formula supplementation increased intestinal weights and HCA (experiments 1+2). Enteral BC and HM feeding increased HCA, intestinal weights, and necrotizing enteritis resistance, relative to formula (experiment 3).

CONCLUSION

Preterm pigs show decreased physical activity, and the first enteral feeds diet dependently stimulate both gut growth and physical activity. The effects may arise from maturation of digestive, metabolic, and neurological functions, including gut serotonin production, by the first enteral feeds and milk bioactive factors.

Development of infant leg coordination: Exploiting passive torques

Leg joint coordination systematically changes over the first months of life, yet there is minimal data on the underlying change in muscle torques that might account for this change in coordination. The purpose of this study is to investigate the contribution of torque changes to early changes in leg joint coordination. Kicking actions were analyzed of 10 full-term infants between 6 and 15-weeks of age using three-dimensional kinematics and kinetics. We found 11 of 15 joint angle pairs demonstrated a change from more in-phase intralimb coordination at 6-weeks to less in-phase coordination at 15-weeks. Although the magnitude of joint torques normalized to the mass of the leg remained relatively consistent, we noted more complex patterns of torque component contribution across ages. By focusing on the change in torques associated with hip-knee joint coordination, we found that less in-phase hip-knee joint coordination at 15-weeks was associated with decreased influence of knee muscle torque and increased influence of knee gravitational and motion-dependent torques, supporting that infants coordinate hip muscle torque with passive knee gravitational and motion-dependent torques to generate kicks with reduced active knee muscle torque. We propose that between 6 and 15-weeks of age less in-phase hip-knee coordination emerges as infants exploit passive dynamics in the coordination of hip and knee motions.

Postural complexity influences development in infants born preterm with brain injury: relating perception-action theory to 3 cases

BACKGROUND AND PURPOSE

Perception-action theory suggests a cyclical relationship between movement and perceptual information. In this case series, changes in postural complexity were used to quantify an infant's action and perception during the development of early motor behaviors.

CASE DESCRIPTION

Three infants born preterm with periventricular white matter injury were included.

OUTCOMES

Longitudinal changes in postural complexity (approximate entropy of the center of pressure), head control, reaching, and global development, measured with the Test of Infant Motor Performance and the Bayley Scales of Infant and Toddler Development, were assessed every 0.5 to 3 months during the first year of life. All 3 infants demonstrated altered postural complexity and developmental delays. However, the timing of the altered postural complexity and the type of delays varied among the infants. For infant 1, reduced postural complexity or limited action while learning to control her head in the midline position may have contributed to her motor delay. However, her ability to adapt her postural complexity eventually may have supported her ability to learn from her environment, as reflected in her relative cognitive strength. For infant 2, limited early postural complexity may have negatively affected his learning through action, resulting in cognitive delay. For infant 3, an increase in postural complexity above typical levels was associated with declining neurological status.

DISCUSSION

Postural complexity is proposed as a measure of perception and action in the postural control system during the development of early behaviors. An optimal, intermediate level of postural complexity supports the use of a variety of postural control strategies and enhances the perception-action cycle. Either excessive or reduced postural complexity may contribute to developmental delays in infants born preterm with white matter injury.