Beth A. Smith

Systematic review and evidence-based clinical recommendations for dosing of pediatric supported standing programs.

Purpose: There is a lack of evidence-based recommendations for effective dosing of pediatric supported standing programs, despite widespread clinical use. Methods: Using the International Classification of Functioning, Disability, and Health (Child and Youth Version) framework, we searched 7 databases, using specific search terms. Results: Thirty of 687 studies located met our inclusion criteria. Strength of the evidence was evaluated by well-known tools, and to assist with clinical decision-making, clinical recommendations based on the existing evidence and the authors’ opinions were provided. Conclusions and recommendations for clinical practice: Standing programs 5 days per week positively affect bone mineral density (60 to 90 min/d); hip stability (60 min/d in 30° to 60° of total bilateral hip abduction); range of motion of hip, knee, and ankle (45 to 60 min/d); and spasticity (30 to 45 min/d).

Patterns of Gait Variability Across the Lifespan in Persons with and without Down Syndrome

Background and Purpose: Greater gait variability has been observed in persons with Down syndrome (DS). An understanding of baseline patterns of variability, how these patterns relate to adaptive control of gait, and whether increasing or decreasing variability is better is necessary for physical therapists to determine whether and when to intervene. Our aim was to describe patterns of gait variability across the lifespan in persons with DS. Methods: We examined differences in patterns of gait variability in new walkers, preadolescents, and adults with DS and typical development (TD). We collected kinematic data, while participants walked on a treadmill, and analyzed the data using the nonlinear measures of Lyapunov Exponent (LyE) and Approximate Entropy (ApEn). Results: Beyond the greater gait variability demonstrated across the lifespan in persons with DS compared with their peers with TD, we report herein significant differences in nonlinear measures of patterns of variability. Preadolescents demonstrated higher LyE and ApEn values than new walkers and adults, suggesting that they are more adaptive in their use of variability during gait. Conclusion: From a clinical perspective, our results suggest that it may be of value to focus interventions on increasing adaptive use of variability during gait in new walkers and adults with DS. Experience with increased variability through practice under variable conditions or with perturbations may improve adaptive use of variability during gait.

Daily Quantity of Infant Leg Movement: Wearable Sensor Algorithm and Relationship to Walking Onset.

Background: Normative values are lacking for daily quantity of infant leg movements. This is critical for understanding the relationship between the quantity of leg movements and onset of independent walking, and will begin to inform early therapy intervention for infants at risk for developmental delay. Methods: We used wearable inertial movement sensors to record full-day leg movement activity from 12 infants with typical development, ages 1–12 months. Each infant was tested three times across 5 months, and followed until the onset of independent walking. We developed and validated an algorithm to identify infant-produced leg movements. Results: Infants moved their legs tens of thousands of times per day. There was a significant effect of leg movement quantity on walking onset. Infants who moved their legs more walked later than infants who moved their legs less, even when adjusting for age, developmental level or percentile length. We will need a much larger sample to adequately capture and describe the effect of movement experience on developmental rate. Our algorithm defines a leg movement in a specific way (each pause or change in direction is counted as a new movement), and further assessment of movement characteristics are necessary before we can fully understand and interpret our finding that infants who moved their legs more walked later than infants who moved their legs less. Conclusions: We have shown that typically-developing infants produce thousands of leg movements in a typical day, and that this can be accurately captured in the home environment using wearable sensors. In our small sample we can identify there is an effect of leg movement quantity on walking onset, however we cannot fully explain it.

Development of a Wearable Sensor Algorithm to Detect the Quantity and Kinematic Characteristics of Infant Arm Movement Bouts Produced across a Full Day in the Natural Environment

We developed a wearable sensor algorithm to determine the number of arm movement bouts an infant produces across a full day in the natural environment. Full-day infant arm movement was recorded from 33 infants (22 infants with typical development and 11 infants at risk of atypical development) across multiple days and months by placing wearable sensors on each wrist. Twenty second sections of synchronized video data were used to compare the algorithm against visual observation as the gold standard for counting the number of arm movement bouts. Overall, the algorithm counted 173 bouts and the observer identified 180, resulting in a sensitivity of 90%. For each bout produced across the day, we then calculated the following kinematic characteristics: duration, average and peak acceleration, average and peak angular velocity, and type of movement (one arm only, both arms for some portion of the bout, or both arms for the entire bout). As the first step toward developing norms, we present average values of full-day arm movement kinematic characteristics across the first months of infancy for infants with typical development. Identifying and quantifying infant arm movement characteristics produced across a full day has potential application in early identification of developmental delays and the provision of early intervention therapies to support optimal infant development.

Effects of amplitude cueing on postural responses and preparatory cortical activity of people with Parkinson disease.

Background and Purpose: Persons with Parkinson disease (PD) are unable to modify their postural responses, and show an associated increase in cortical preparatory activity for anticipated postural perturbations.1 In this study we asked whether participants with PD could modify their postural responses and cortical preparatory activity when cued to focus on increasing movement amplitude before a series of predictable postural perturbations. Methods: Twelve participants with PD performed postural responses to 30 identical backward surface translations. We cued participants to focus on increasing movement amplitude, and examined the effects of cueing by measuring postural responses (center-of-pressure initial rate of change, automatic postural response stability, peak trunk flexion, peak ankle extension) and preparatory cortical activity (electroencephalographic measures of contingent negative variation, alpha and beta event-related desynchronization). Results: Participants with PD modified their postural responses during the amplitude trials by increasing trunk flexion, slowing center-of-pressure initial rate of change, and decreasing automatic postural response stability. However, no significant differences in contingent negative variation amplitude or alpha or beta event-related desynchronization were observed with versus without amplitude cueing. Discussion and Conclusions: Persons with PD were able to modify their feet-in-place postural responses with amplitude cueing. These changes were not associated with changes in cortical preparation during amplitude cue trials, suggesting that other regions or measures of brain function were responsible for changes in postural responses. Future studies are needed to determine the effects of long-term amplitude-cueing practice on cortical preparation and postural stability. Video Abstract available. See Video (Supplemental Digital Content 1, http://links.lww.com/JNPT/A78) for more insights from the authors.

Neonatal Diagnostics: Toward Dynamic Growth Charts of Neuromotor Control

The current rise of neurodevelopmental disorders poses a critical need to detect risk early in order to rapidly intervene. One of the tools pediatricians use to track development is the standard growth chart. The growth charts are somewhat limited in predicting possible neurodevelopmental issues. They rely on linear models and assumptions of normality for physical growth data – obscuring key statistical information about possible neurodevelopmental risk in growth data that actually has accelerated, non-linear rates-of-change and variability encompassing skewed distributions. Here, we use new analytics to profile growth data from 36 newborn babies that were tracked longitudinally for 5u2009months. By switching to incremental (velocity-based) growth charts and combining these dynamic changes with underlying fluctuations in motor performance – as the transition from spontaneous random noise to a systematic signal – we demonstrate a method to detect very early stunting in the development of voluntary neuromotor control and to flag risk of neurodevelopmental derail.

Consistency in Administration and Response for the Backward Push and Release Test: A Clinical Assessment of Postural Responses

BACKGROUND AND PURPOSEnThe backward push and release test (PRT) is a standardized clinical test of postural responses elicited by perturbations. Our goal was to determine reliability of administration and response. This will inform clinical administration and determine whether to develop an instrumented version.nnnMETHODSnOne examiner administered 10 backward PRT trials to adults with Parkinson disease (12), multiple sclerosis (14) and controls (12). We used three-dimensional motion analysis, force plates and instrumented gloves to measure administration and response. Administration variables were angle of posterior trunk lean and the distance of the centre of mass (CoM) behind the ankle. Postural response variables were latency of postural response from release to step initiation and first compensatory step length. Reliability was measured using the range of variables across trials, comparison of first and later trials, intraclass correlations (ICCs) to measure consistency and correlations between administration and response.nnnRESULTSnThere was inherent variability in administration, which affected postural response characteristics. Larger trunk angle and greater CoM-ankle distance were correlated with shorter postural response latencies and larger step lengths. Participant height also had an effect; taller participants had larger trunk angles prior to release resulting in longer latencies and larger step lengths. Using ICCs, consistency of trunk angle was likely acceptable and CoM-ankle distance was high. Consistency of latency was low, while step length was likely acceptable.nnnDISCUSSIONnDespite variability in administration and inconsistency in response, different postural response characteristics were detected between patients with different disease states. Based on these results, we will create algorithms to instrument the PRT using inertial movement sensors to collect more sensitive measures of postural responses than observational clinical rating scales. Feedback for appropriate lean angle and calibration for participant height will improve consistency and usefulness of the instrumented PRT. Copyright

Sample Entropy Identifies Differences in Spontaneous Leg Movement Behavior between Infants with Typical Development and Infants at Risk of Developmental Delay

We are interested in using wearable sensor data to analyze detailed characteristics of movement, such as repeatability and variability of movement patterns, over days and months to accurately capture real-world infant behavior. The purpose of this study was to explore Sample Entropy (SampEn) from wearable sensor data as a measure of variability of spontaneous infant leg movement and as a potential marker of the development of neuromotor control. We hypothesized that infants at risk (AR) of developmental delay would present significantly lower SampEn values than infants with typical development (TD). Participants were 11 infants with TD and 20 infants AR. We calculated SampEn from 1–4 periods of data of 7200 samples in length when the infants were actively playing across the day. The infants AR demonstrated smaller SampEn values (median 0.21) than the infants with TD (median 1.20). Lower values of SampEn indicate more similarity in patterns across time, and may indicate more repetitive, less exploratory behavior in infants AR compared to infants with TD. In future studies, we would like to expand to analyze longer periods of wearable sensor data and/or determine how to optimally sample representative periods across days and months.

Electroencephalography power and coherence changes with age and motor skill development across the first half year of life

Existing research in infants has correlated electroencephalography (EEG) measures of power and coherence to cognitive development and to locomotor experience, but only in infants older than 5 months of age. Our goal was to explore the relationship between EEG measures of power and coherence and motor skill development in younger infants who are developing reaching skill. Twenty-one infants with typical development between 38 and 203 days of age participated. Longitudinal EEG recording sessions were recorded in monthly increments, with 3–5 sessions acquired for 19 participants and 1 session for 2 participants, resulting in 71 sessions in total. EEG variables of interest were relative power in the 6–9 Hz range and coherence between selected electrode pairs. We describe the development of the peak in relative power in the 6–9 Hz frequency band of EEG; it is not present around 1 month of age and starts to appear across the following months. Coherence generally increased in the bilateral frontal-parietal networks, while the interhemispheric connectivity in motor cortices generally decreased. The results of this relatively small pilot study provide a foundational description of neural function changes observed as motor skills are changing across the first half year of life. This is a first step in understanding experience-dependent plasticity of the infant brain and has the potential to aid in the early detection of atypical brain development.

Kinematic characteristics of infant leg movements produced across a full day

Introduction Our purpose is to directly measure variability in infant leg movement behavior in the natural environment across a full day. We recently created an algorithm to identify an infant-produced leg movement from full-day wearable sensor data from infants with typical development between one and 12 months of age. Here we report the kinematic characteristics of their leg movements produced across a full day. Methods Wearable sensor data were collected from 12 infants with typical development for 8–13u2009h/day. A wearable sensor was attached to each ankle and recorded triaxial accelerometer and gyroscope measurements at 20u2009Hz. We determined the duration, average acceleration, and peak acceleration of each leg movement and classified its type (unilateral, bilateral synchronous, bilateral asynchronous). Results There was a range of leg movement duration (0.23–0.33u2009s) and acceleration (average 1.59–3.88u2009m/s2, peak 3.10–8.83u2009m/s2) values produced by infants across visits. Infants predominantly produced unilateral and asynchronous bilateral movements. Our results collected across a full day are generally comparable to kinematic measures obtained by other measurement tools across short periods of time. Conclusion Our results describe variable full-day kinematics of leg movements across infancy in a natural environment. These data create a reference standard for the future comparison of infants at risk for developmental delay.