Postural adjustments and reaching in 4-and 6-month-old infants:an EMG and kinematical study

Adequate postural control is a prerequisite for daily activities such as reaching for an object. However, knowledge on the relationship between postural adjustments and the quality of reaching movements during human ontogeny is scarce. Therefore we evaluated the development of the relationship between the kinematic features of reaching movements and the accompanying postural adjustments in young infants. Twelve typically developing (TD) infants were assessed twice, i.e. at 4 and 6 months of age, in supine and supported sitting position. Reaching was elicited by presenting toys in the midline at an arm-length distance while simultaneously surface EMG-activity was recorded from multiple arm-, neck-, trunk- and leg muscles. Concurrently kinematics of reaching were recorded with an ELITE system; kinematic analysis was restricted to the behaviour of so-called movement units, which are sub movements of reaching determined with the help of peaks in the velocity profile of the hand, maximum movement velocity and movement duration. A computer-algorithm determined significant phasic muscle activity. Activity in neck and trunk muscles (postural activity) was related to the onset of the prime mover, which was the arm muscle being activated first. The results indicated that about 50% of reaching movements in lying and sitting infants aged 4 and 6 months were accompanied by direction-specific postural adjustments. At 4 months variation dominated, but at 6 months a preference to recruit muscles in a top-down order (during sitting) and in the configuration of the complete pattern, i.e. the pattern in which all dorsal neck- and trunk muscles are activated in concert, (both conditions) emerged. Interestingly, the postural characteristics such as the presence of direction-specificity, recruitment of the complete pattern and top-down recruitment, were related to how successful the reaching was and the kinematics of reaching. It was concluded that the presence of direction-specific activity is not a prerequisite for the emergence of reaching movements. Nevertheless, already from 4 months onwards a better postural control is associated with a larger success and a better quality of reaching

Active head lifting from supine in infancy in the general population:Red flag or not?

Background: Previously it had been had reported that active head lifting from supine (AHLS) in high-risk infants was associated with lower cognitive scores in the second year. AHLS was generally accompanied by stereotyped leg movements. Aims: To examine in a standardized way whether AHLS with or without stereotyped leg movements in the general population is associated with prenatal, perinatal, neonatal and socio-economic risk factors or with lower scores on concurrent infant tests. Study design: Cross-sectional study Subjects: 1700 infants aged 2-18 months representative of the Dutch population. Outcome measures: Infant Motor Profile (IMP) and Standardized Infant NeuroDevelopmental Assessment (SINDA). Assessments were video-recorded and included at the youngest ages 3min of behaviour in supine. AHLS and the presence of stereotyped leg movements were recorded. Standardized information on early risk factors was available. Results: AHLS occurred at 4-9 months (prevalence per months: 1-14%; highest prevalence at 6 months). It was not associated with early risk factors or scores on infant tests. When AHLS was accompanied by stereotyped leg movements it was associated with a higher prevalence of an IMP-variation score < P15 (Odds Ratio (OR) 2.472 [95%CI 1.017; 6.006]). Stereotyped leg movements irrespective of AHLS were associated with more unfav-ourable total IMP scores and IMP performance scores (B coefficients-3.212 [-4.065;-2.360],-2.521 [-3.783;-1.259]) and IMP variation and SINDA neurological scores (ORs 5.432 [3.409; 8.655], 3.098 [1.548; 6.202]). Conclusions: The data suggest that AHLS is not a red flag. Rather its co-occurring stereotyped leg movements may signal less favourable neurodevelopment

Alberta Infant Motor Scale:Cross-cultural analysis of gross motor development in Dutch and Canadian infants and introduction of Dutch norms

Background: The Alberta Infant Motor Scale (AIMS) has been developed in Canada in the 90ies. The AIMS and its Canadian norms are frequently used across the world to monitor infants' gross motor development. Currently, it is disputed whether the Canadian norms are valid for non-Canadian infants. Aims: To compare scores on the AIMS of Dutch infants with that of the Canadian norms, to compare the sequence of motor milestones in Dutch and Canadian infants, and to establish Dutch AIMS norms. Study design: Cross-sectional study. Subjects: 1697 infants, aged 2-18 months, representative of the Dutch population (gestational age 39.7 weeks (27-42)). Outcome measure. AIMS assessments, based on standardized video. Perinatal and social information was obtained by questionnaire and medical records. To create Dutch reference values quantile regression with polynomial splines was used. Results: 1236 Dutch infants (73%) scored below the 50th (P50) percentile of the Canadian norms, 653 (38%) below the P10 and 469 (28%) below the P5. In infants aged 6 to 12 months these values were: 567 infants (81%) <P50, 288 infants (41%) <P10, 201 infants (29%) <P5. The sequence of achievement of motor milestones of Dutch and Canadian infants was similar. Dutch norm-reference values of the AIMS were calculated. Conclusions and implications: Gross motor development of Dutch infants is considerably slower than that of the Canadian AIMS norms sample. To prevent overdiagnosis of developmental delay and overreferral to paediatric physiotherapy Dutch AIMS norms are required. The paper introduces these norms, including percentile ranks

Embodiment and the origin of interval timing: kinematic and electromyographic data

Recent evidence suggests that interval timing (the judgment of durations lasting from approximately 500 ms. to a few minutes) is closely coupled to the action control system. We used surface electromyography (EMG) and motion capture technology to explore the emergence of this coupling in 4-, 6-, and 8-month-olds. We engaged infants in an active and socially relevant arm-raising task with 7 cycles and response period. In one condition cycles were slow (every 4 seconds) in another they were fast (every 2 seconds). In the slow condition, we found evidence of time locked sub-threshold EMG activity even in the absence of any observed overt motor responses at all 3 ages. This study shows that EMGs can be a more sensitive measure of interval timing in early development than overt behavior

Changes in the Content of Pediatric Physical Therapy for Infants:A Quantitative, Observational Study

AIMS: The aim of our observational longitudinal study is to evaluate changes over time in standard pediatric physical therapy (PPT) for infants at risk of neurodevelopmental disorders. METHODS: Treatment sessions in two time periods (2003-2005 [n = 22] and 2008-2014 [n = 16]) were video recorded and analyzed quantitatively in five categories: neuromotor actions, educational actions, communication, position, and situation of treatment session. Differences in percentages of time spent on therapeutic actions between periods were tested with Mann-Whitney U and Hodges Lehmann's tests. RESULTS: No significant changes appeared in the main categories of neuromotor actions. Time spent on not-specified educational actions toward caregivers (median from 99% to 81%, p = .042) and not-specified communication (median from 72% to 52%, p = .002) decreased. Consequently, time spent on specific educational actions (caregiver training and coaching; median from 1% to 19%, p = .042) and specific communication (information exchange, instruct, provide feedback; median from 21% to 38%, p = .007) increased. Infant position changed only minimally: time spent on transitions-that is, change of position-decreased slightly over time (median from 7% to 6%, p = .042). Situation of treatment session did not change significantly over time. CONCLUSIONS: Neuromotor actions in PPT remained largely stable over time. Specific educational actions and communication increased, indicating larger family involvement during treatment sessions

Asthma in 9-year-old children of subfertile couples is not associated with in vitro fertilization procedures

Asthma is a chronic reversible obstructive airway disease, which is common among children and leads to respiratory impairment. Studies showed that asthma is more common among children born after in vitro fertilization (IVF) than among spontaneously conceived children. However, it is unknown which component of the IVF procedure contributes to this putative link. Therefore, the aim of this prospective follow-up study was to differentiate the possible effect of ovarian hyperstimulation from that of the in vitro culture procedure on asthma and rhinitis in 9-year-old children conceived with IVF. The study comprised three groups of singletons: (I) conceived with ovarian hyperstimulation-IVF (COH-IVF, n = 95); (II) conceived with modified natural cycle-IVF (MNC-IVF, n = 48); and (III) naturally conceived to subfertile couples (Sub-NC, n = 68). Parents filled out the validated Dutch version of the asthma questionnaire of the International Study of Asthma and Allergies. Asthma prevalence in the groups did not differ: COH-IVF n = 8 (8%); MNC-IVF n = 0 (0%); and Sub-NC n = 4 (6%). Adjustment for confounders did not alter the results.Conclusion: Neither ovarian hyperstimulation nor the in vitro culture procedure was associated with asthma and rhinitis at 9 years. IVF children had a similar prevalence of asthma compared with children conceived naturally by subfertile couples.Trial registration: ISRCTN76355836 What is Known: • An increased risk for asthma has been observed in children born after in vitro fertilization at preschool and school age. • The association between IVF and asthma may be partly explained by parental subfertility. What is New: • IVF children do not have a higher prevalence of asthma than children of subfertile couples conceived naturally. • Ovarian hyperstimulation used in IVF is not associated with asthma in 9-year-old children of subfertile couples.</p

From Children to Adults: Motor Performance across the Life-Span

The life-span approach to development provides a theoretical framework to examine the general principles of life-long development. This study aims to investigate motor performance across the life span. It also aims to investigate if the correlations between motor tasks increase with aging. A cross-sectional design was used to describe the effects of aging on motor performance across age groups representing individuals from childhood to young adult to old age. Five different motor tasks were used to study changes in motor performance within 338 participants (7–79 yrs). Results showed that motor performance increases from childhood (7–9) to young adulthood (19–25) and decreases from young adulthood (19–25) to old age (66–80). These results are mirroring results from cognitive research. Correlation increased with increasing age between two fine motor tasks and two gross motor tasks. We suggest that the findings might be explained, in part, by the structural changes that have been reported to occur in the developing and aging brain and that the theory of Neural Darwinism can be used as a framework to explain why these changes occur