Correlation between pose estimation features regarding movements towards the midline in early infancy.

In infants, spontaneous movement towards the midline (MTM) indicates the initiation of anti-gravity ability development. Markerless 2D pose estimation is a cost-effective, time-efficient, and quantifiable alternative to movement assessment. We aimed to establish correlations between pose estimation features and MTM in early-age infants. Ninety-four infant videos were analysed to calculate the percentage and rate of MTM occurrence. 2D Pose estimation processed the videos and determined the distances and areas using wrist and ankle landmark coordinates. We collected data using video recordings from 20 infants aged 8-16 weeks post-term age. Correlations between MTM observations and distance values were evaluated. Differences in areas between groups of videos showing MTM and no MTM in the total, lower-limb, and upper-limb categories were examined. MTM observations revealed common occurrences of hand-to-trunk and foot-to-foot movements. Weak correlations were noted between limb distances to the midbody imaginary line and MTM occurrence values. Lower MTM showed significant differences in the lower part (p = 0.003) and whole area (p = 0.001). Video recording by parents or guardians could extract features using 2D pose estimation, assisting in the early identification of MTM in infants. Further research is required to assess a larger sample size with the diversity of MTM motor behaviour, and later developmental skills, and collect data from at-risk infants.

Designing artificial circadian environments with multisensory cares for supporting preterm infants' growth in NICUs.

Previous studies suggest the importance of stable circadian environments for fetuses to achieve sound physiology and intrauterine development. This idea is also supported by epidemiological and animal studies, in which pregnant females exposed to repeated shifting of light-dark cycles had increased rates of reproductive abnormalities and adverse pregnancy outcomes. In response to such findings, artificial circadian environments with light-dark (LD) cycles have been introduced to NICUs to promote better physical development of preterm infants. Such LD cycles, however, may not be fully effective for preterm infants who are less than 30 weeks gestational age (WGA) since they are too premature to be adequately responsive to light. Instead, circadian rhythmicity of incubated preterm infants less than 30 WGA may be able to be developed through stimulation of the non-visual senses such as touch and sound.

Relationship between fidgety movement and frequency of movement toward midline: An observational study.

BACKGROUND: Infants show other movements and posture patterns during the fidgety movement period, including movement toward midline (MTM). Few studies have quantified MTM occurring during the fidgety movement period. AIMS: This study aimed to examine the relationship between fidgety movements (FMs) and MTM frequency and occurrence rate per minute, from two video data sets (video attached to Prechtl video manual and accuracy data from Japan). STUDY DESIGN: Observational study. SUBJECTS: It encompassed 47 videos. Of these, 32 were deemed normal FMs. The study amalgamated FMs that were sporadic, abnormal, or absent into a category of aberrant (n = 15). OUTCOME MEASURES: Infant video data were observed. MTM item occurrences were recorded and calculated for occurrence percentage and MTM rate of occurrence per minute. The differences between groups for the upper limbs, lower limbs, and total MTM were statistically analysed. RESULTS: Twenty-three infant videos of normal FMs and seven infant videos of aberrant FMs showed MTM. Eight infant videos of aberrant FMs showed no MTM, and only four with absent FMs were included. There was a significant difference in the total MTM rate of occurrence per minute between normal FMs versus aberrant FMs (p = 0.008). CONCLUSIONS: This study presented MTM frequency and rate of occurrence per minute in infants who showed FMs during the fidgety movement period. Those who showed absent FMs also demonstrated no MTM. Further study may need a larger sample size of absent FMs and information on later development.

Association between General Movements Assessment and Later Motor Delay (excluding Cerebral Palsy) in Low-Birth-Weight Infants.

The general movements (GMs) assessment is useful for the prediction of cerebral palsy (CP) and other developmental disorders. Developmental coordination disorder (DCD) is highly prevalent in low-birth-weight (LBW) infants. We investigated the association between aberrant GMs during early infancy and later motor development in LBW infants. The study included infants who fulfilled the following criteria: GMs assessed at 9-20 weeks post-term age; developmental quotient (DQ) assessed at 3 years of age using the Kyoto Scale; intelligence quotient (IQ) assessed at 6 years of age. Participants with normal IQs at 6 years of age without a diagnosis of CP (14 males and 37 females, 23-36 weeks gestation with birth weights of 492-1498 g) were categorized into normal (n = 39) and aberrant (n = 12) groups based on GMs assessment; DQ was compared between the groups. We investigated the items in the DQ assessment and found that the infants in the aberrant group were more frequently unable to perform. Infants in the aberrant group showed a significantly lower DQ in the 'postural-motor domain', and were more frequently unable to 'climb the stairs with alternating legs' and 'Jump from a 15-20 cm platform'. This study highlights that GMs aberrancy in early infancy is associated with a delayed gross motor development, even in children with a typical development. The GMs assessment may be useful for the prediction of DCD.

Infant's Behaviour Checklist for low birth weight infants and later neurodevelopmental outcome.

Assessment of the characteristics of spontaneous movements and behaviour in early infancy helps in estimating developmental outcomes. We introduced the Infant Behaviour Checklist (IBC) and examined the relationship between the behavioural characteristics of low-birth-weight infants and neurodevelopmental outcomes at 6 years of age. The behavioural characteristics during the neonatal (36-43 weeks, adjusted) and early infancy periods (49-60 weeks, adjusted) were assessed in very-low-birth-weight infants. The IBC includes 44 common behaviours. We assessed the appearance of individual behavioural characteristics at each period according to the neurodevelopmental outcome. Of the 143 infants assessed during the neonatal period, 89 had typical development (TD), 30 had intellectual disability (ID), and 24 had autism spectrum disorder (ASD). In 78 infants assessed during early infancy, 40, 21, and 17 had TD, ID, and ASD, respectively. The frequency of appearance of three behaviour-related items was significantly lower in the ID group than in the TD group. The frequency of appearance of three posture- and behaviour-related items was significantly lower, while that of two posture-related items was significantly higher, in the ASD group than in the TD group. Behavioural assessment using the IBC may provide promising clues when considering early intervention for low-birth-weight infants.

Postural change for supine position does not disturb toddlers' nap.

This study examined whether forced postural change from prone to supine during toddlers' nap, a preventative measure taken in Japan for sudden unexplained death in childhood (SUDC), disturbs toddlers' sleep. When the "Back to Sleep" campaign (BSC) was introduced to Japan in 1996, its recommendations were also applied to infants aged 1 year old and over with the expectation that the BSC recommendations may also contribute to a decrease in the occurrence rate of SUDC. Since then, Japanese nurseries have routinely conducted sleeping position checks and positional adjustments of toddlers every 5-10 min during naps. A total of 52 toddlers (age 18.4 ± 3.3 months, means ± SD) were continuously monitored for 8 h during daytime at nursery schools for wake-sleep status and body position (prone, supine and lateral) with actigraphs and 3-orthogonal-axis accelerometers. Out of the 52 toddlers, 24 toddlers adopted prone positions during naps, which were adjusted by nursery staff back to supine. When nursery staff manually changed the toddlers position from prone to supine, the toddlers either did not wake or woke only briefly (3.1 ± 4.9 min) and returned to sleep soon after the positional change. Our study indicates that manual change of toddlers' sleeping position from prone to supine, a potential SUDC prevention method, does not disturb toddlers' sleep during their naps.

The shape of disposable diaper affects spontaneous movements of lower limbs in young infants.

This study examined the characteristics of young infants' lower limb spontaneous movements based on differences in shape of diapers. Twenty-seven healthy infants (103 ± 16.3 days old) were enrolled in this study. We measured the spontaneous movements of their lower limbs in four conditions (Naked, wearing Normal type diapers, wearing Type A diapers, and wearing Type B diapers). The Normal diaper has a wider waist belt than the Type A diaper, and the Type B diaper has a narrower crotch area than the Type A diaper. We observed them in seven indices (the velocity of lower limb movements, the trajectory area of knee movement in the sagittal plane and the frontal plane, the distance between both knees and between side of abdomen and knee, and correlation of velocities between side of abdomen and knee and between left and right ankles). The results showed that the velocity of the lower limb movements in the Naked condition was higher than when wearing Normal diapers. The value for the trajectory area of knee movement in sagittal plane, which reflects the range of lower leg lifting movements and closeness of such movements to the trunk, for the Type B diaper condition was higher than that for the Normal diaper condition. This result indicates that the shape of the diaper affects the spontaneous movements of the lower limbs of young infants.

Evaluation of Fidgety Movements of Infants Based on Gestalt Perception Reflects Differences in Limb Movement Trajectory Curvature.

BACKGROUND: Infants aged 2 to 5 months show spontaneous general movements (GMs) of the whole body, which are referred to as fidgety movements (FMs). Although previous studies have shown that evaluation of GMs by the General Movement Assessment (GMA) has predictive value about later neurological impairments, it remains unknown whether raters consistently perceive and rate such complex kinematic information. OBJECTIVE: The purpose of this study was to construct a method to reveal which movement features are associated with each rater's evaluation of FMs based on the GMA. DESIGN: GMA scores of 163 healthy infants aged 11 to 16 weeks postterm were matched with data obtained from a 3-dimensional motion analysis system. METHODS: Three physical therapists performed the GMA and classified GMs into 9 types, from which we focused on 3 subtypes differing in the temporal organization of FMs (continual, intermittent, and sporadic FMs). We also calculated 6 movement indices (average velocity of limb movements, number of movement units, kurtosis of acceleration, jerk index, average curvature, and correlation between limb velocities) for arms and legs for each infant and analyzed which movement indices were associated with the ratings of the 3 FM subtypes by each rater. RESULTS: Only the average curvature differed significantly among the ratings of the 3 FM subtypes for all 3 raters. Each rater showed significant differences in the average curvature in either arms or legs. LIMITATIONS: It is difficult to generalize the present results to raters with various levels of expertise and experience in using the GMA. This issue calls for further research. CONCLUSIONS: The method used revealed commonality and individuality about the perceived movement features that can be associated with the rating of FMs.

Early motor signs of autism spectrum disorder in spontaneous position and movement of the head.

We examined the characteristics of spontaneous movements at 9-20 weeks postterm age in very low birth-weight infants who later developed autism spectrum disorder (ASD). We analyzed video recordings of spontaneous movements of 39 children who had no clinical issues [typically developing (TD) group], 21 children who showed developmental delay, and 14 children who were diagnosed with ASD (ASD group) at 6 years of age. Head position in each video frame was classified by visual inspection. The percentage of midline head position (PMHP) and number of changes in head position were calculated. Spontaneous limb movements were quantified using six indices. The values of PMHP were significantly lower in the ASD group than in the TD group. The lower PMHP during early infancy is associated with later development of ASD. Poorer performance in maintaining midline position of the head at this period may distinguish infants who later develop ASD from those who show TD.

Developmental changes in intralimb coordination during spontaneous movements of human infants from 2 to 3 months of age.

Human infants show a variety of spontaneous movements in the first few months of life. Although the pattern of spontaneous movements changes at approximately 2 months of age, the precise mechanism that governs the developmental changes in intralimb coordination remains unclear. In the present study, we focused on knee-ankle coordination during spontaneous movements of human infants from 2 to 3 months of age. Multiple attitude sensors were used to measure three-dimensional angular motion of knee and ankle joint motions. We acquired a one-dimensional time series of the knee joint angle around the putative hinge joint and a two-dimensional time series of ankle motions on the putative sagittal and frontal plane. First, we found that 3-month-old infants show a significant predominance to extend their knee joints, remarkably so on the left side. To quantify dissociated motions of the knee and ankle, we calculated the temporal correlation and the regression slope between them. We observed that 3-month-old infants moved their ankle joints more independently of knee motions than 2-month-old infants. Finally, we found that dissociated motions of the knee and ankle simultaneously develop with knee extension predominance. The developmental change from synchronization to dissociation of intralimb joint movements during spontaneous movements suggests that the development of the cortical and/or subcortical mechanism may mediate selective activation and inhibition of joint motions at approximately 2 months of age.

A dynamical system analysis of the development of spontaneous lower extremity movements in newborn and young infants.

This study's aim was to evaluate the characteristics of newborn and young infants' spontaneous lower extremity movements by using dynamical systems analysis. Participants were 8 healthy full-term newborn infants (3 boys, 5 girls, mean birth weight and gestational age were 3070.6 g and 39 weeks). A tri-axial accelerometer measured limb movement acceleration in 3-dimensional space. Movement acceleration signals were recorded during 200 s from just below the ankle when the infant was in an active alert state and lying supine (sampling rate 200 Hz). Data were analyzed linearly and nonlinearly. As a result, the optimal embedding dimension showed more than 5 at all times. Time dependent changes started at 6 or 7, and over the next four months decreased to 5 and from 6 months old, increased. The maximal Lyapnov exponent was positive for all segments. The mutual information is at its greatest range at 0 months. Between 3 and 4 months the range in results is narrowest and lowest in value. The mean coefficient of correlation for the x-axis component was negative and y-axis component changed to a positive value between 1 month old and 4 months old. Nonlinear time series analysis suggested that newborn and young infants' spontaneous lower extremity movements are characterized by a nonlinear chaotic dynamics with 5 to 7 embedding dimensions. Developmental changes of an optimal embedding dimension showed a U-shaped phenomenon. In addition, the maximal Lyapnov exponents were positive for all segments (0.79-2.99). Infants' spontaneous movement involves chaotic dynamic systems that are capable of generating voluntary skill movements.

[The developmental characteristics of spontaneous movement in healthy infants].

The aim of this study was to evaluate the characteristics of development of spontaneous movements in infants using dynamical systems analysis. The participants were 7 healthy, full-term, newborn infants. A tri-axial accelerometer was used to measure limb acceleration in three-dimensional space. Acceleration signals were recorded on the right wrist, when the infant was in an active alert state, lying in supine. Measurement was carried out every fourth week after birth between the ages of 1 and 5 months old. The recording time was 200 seconds, based on recommendations for this accelerometer. The time-series data was analyzed by non-linear methods using a package (TISEAN) provided with the machine, provided some evidence of non-linear deterministic structure (dimension, maximal Lyapunov exponent). The developmental change in infants' spontaneous movements was shown as "U-shaped", with the base between 2-3 months, and recovering at 4-5 months (4 of 8 infants in dimension, 6 of 8 infants in maximal Lyapunov exponent). Approximately 4-5 months after birth, infants develop voluntary movement, such as reaching for objects.

Neonatal behavioural profile and crying in premature infants at term age.

AIM: To analyse behavioural characteristics of infants who cried more versus those who cried less, in a sample of low-risk premature infants. METHODS: Participants were 63 low-risk healthy premature infants. At term age, the Neonatal Behavioral Assessment Scale (NBAS) was administered, and a 1-d diary for crying was recorded starting on the following day. Infants were categorized into two groups: those with "high level of crying" (> or = 75th percentile) and those with "less crying" (< 75th percentile), based on the total amount of crying time. RESULTS: Some individual NBAS scores and "habituation" and "regulation of state" cluster scores were lower in the high-level-of-crying group. Infants in the group with a high level of crying had lower thresholds for response in the "peak of excitement", "rapidity of build-up", "irritability" and "general irritability" items. Logistic regression analysis revealed that lower "habituation" and "regulation of state" cluster scores were significantly associated with lower thresholds for crying. CONCLUSION: These results suggest that neonatal behavioural characteristics, such as hyperresponsivity and poor state regulation, are associated with high levels of crying. Clinical assessments based on the NBAS may help parents elucidate their infant's level of tolerance for stimuli, and identify strategies to minimize their crying.