Publications

AIM: To examine concurrent validity between the Bayley Scales of Infant and Toddler Development, Fourth Edition (Bayley-4) gross motor subtest and the Alberta Infant Motor Scale (AIMS), and evaluate agreement among the Bayley-4 (full test and gross motor subtest), AIMS, and Hammersmith Infant Neurological Examination (HINE) in identifying atypical development at 12 months of age.

METHOD: This cross-sectional observational study included Bayley-4, AIMS, and HINE scores from 123 children (56 females, 67 males) with varied risk profiles at approximately 12 months of age. Concurrent validity was assessed using Spearman's rank correlation of raw scores. Agreement was evaluated using Cohen's kappa (k) and evidence-based thresholds of typicality for each assessment. Additional assessment comparisons, including AIMS and HINE, were conducted for benchmarking.

RESULTS: The Bayley-4 gross motor subtest was strongly correlated (r = 0.90, p < 0.01) with the AIMS. Both the Bayley-4 full test and gross motor subtest demonstrated substantial agreement with the AIMS 5th centile (k = 0.72-0.73) and fair agreement (k = 0.28-0.32) with the HINE. By comparison, the AIMS and HINE were moderately correlated (r = 0.48), with fair agreement (k = 0.34).

INTERPRETATION: This study provides the first evidence of concurrent validity and agreement for the Bayley-4, supporting its use as a reliable developmental assessment in clinical and home settings. The Bayley-4 aligned more closely with the motor-focused AIMS than with the neurologically focused HINE.

Early screening and evaluation of infant motor development are crucial for detecting motor deficits and enabling timely interventions. Traditional clinical assessments are often subjective, without fully capturing infants' "real-world" behavior. This has sparked interest in portable, low-cost technologies to objectively and precisely measure infant motion at home, with a goal of enhancing ecological validity. In this systematic review, we explored the current landscape of portable, technology-based solutions to assess early motor development (within the first year), outlining the prevailing challenges and future directions. We reviewed 66 publications, which utilized video, sensors, or a combination of technologies. There were three key applications of these technologies: (1) automating clinical assessments, (2) illuminating new measures of motor development, and (3) predicting developmental outcomes. There was a promising trend toward earlier and more accurate detection using portable technologies. Additional research and demographic diversity are needed to develop fully automated, robust, and user-friendly tools. Registration & Protocol OSF Registries https://doi.org/10.17605/OSF.IO/R6JAE .

PURPOSE: Environmental enrichment (EE) represents a dynamic approach to enhance infants' cognitive and motor development through augmented environment with stimulating, novel opportunities. Despite the recognized benefits of EE on neuromotor outcomes, its integration into early physical therapy interventions for infants at risk of neuromotor delays and disabilities remains under-defined and inconsistently applied in standard practice. This gap underscores the necessity for comprehensive guidance to systematically incorporate EE into early intervention programs and daily routines.

SUMMARY OF KEY POINTS: This paper provides a preliminary framework for the integration of EE into the clinical and home environments for infants from birth to 1 year of age.

RECOMMENDATIONS FOR PRACTICE: With the 7 key components of EE, including sensory system stimulation (auditory, proprioceptive, tactile, vestibular, and visual stimulations), cognitive challenges, and social engagement, this framework aims to maximize cognitive and motor development for infants at both pre and post-term age by leveraging the principles of EE(Supplemental Digital Content,Video, available at: http://links.lww.com/PPT/A624 ).

Traditional methods do not capture the multidimensional domains and dynamic nature of infant behavioral patterns. We aim to compare full-day, in-home leg movement data between infants with typical development (TD) and infants at risk of developmental disabilities (AR) using barcoding and nonlinear analysis. Eleven infants with TD (2-10 months) and nine infants AR (adjusted age: 2-14 months) wore a sensor on each ankle for 7 days. We calculated the standard deviation for linear variability and sample entropy (SampEn) of leg acceleration and angular velocity for nonlinear variability. Movements were also categorized into 16 barcoding states, and we calculated the SampEn and proportions of the barcoding. All variables were compared between the two groups using independent-samples t-test or Mann-Whitney U test. The AR group had larger linear variability compared to the TD group. SampEn was lower in the AR group compared to TD group for both acceleration and angular velocity. Two barcoding states' proportions were significantly different between the two groups. The results showed that nonlinear analysis and barcoding could be used to identify the difference of dynamic multidimensional movement patterns between infants AR and infants with TD. This information may help early diagnosis of developmental disabilities in the future.

INTRODUCTION: Developmental disabilities and neuromotor delay adversely affect long-term neuromuscular function and quality of life. Current evidence suggests that early therapeutic intervention reduces the severity of motor delay by harnessing neuroplastic potential during infancy. To date, most early therapeutic intervention trials are of limited duration and do not begin soon after birth and thus do not take full advantage of early neuroplasticity. The Corbett Ryan-Northwestern-Shirley Ryan AbilityLab-Lurie Children's Infant Early Detection, Intervention and Prevention Project (Project Corbett Ryan) is a multi-site longitudinal randomized controlled trial to evaluate the efficacy of an evidence-based physical therapy intervention initiated in the neonatal intensive care unit (NICU) and continuing to 12 months of age (corrected when applicable). The study integrates five key principles: active learning, environmental enrichment, caregiver engagement, a strengths-based approach, and high dosage (ClinicalTrials.gov identifier NCT05568264).

METHODS: We will recruit 192 infants at risk for neuromotor delay who were admitted to the NICU. Infants will be randomized to either a standard-of-care group or an intervention group; infants in both groups will have access to standard-of-care services. The intervention is initiated in the NICU and continues in the infant's home until 12 months of age. Participants will receive twice-weekly physical therapy sessions and caregiver-guided daily activities, assigned by the therapist, targeting collaboratively identified goals. We will use various standardized clinical assessments (General Movement Assessment; Bayley Scales of Infant and Toddler Development, 4th Edition (Bayley-4); Test of Infant Motor Performance; Pediatric Quality of Life Inventory Family Impact Module; Alberta Infant Motor Scale; Neurological, Sensory, Motor, Developmental Assessment; Hammersmith Infant Neurological Examination) as well as novel technology-based tools (wearable sensors, video-based pose estimation) to evaluate neuromotor status and development throughout the course of the study. The primary outcome is the Bayley-4 motor score at 12 months; we will compare scores in infants receiving the intervention vs. standard-of-care therapy.

Quantity and quality of motor exploration are proposed to be fundamental for infant motor development. However, it is still not clear what types of motor exploration contribute to learning. To determine whether changes in quantity of leg movement and/or variability of leg acceleration are related to performance in a contingency learning task, twenty 6-8-month-old infants with typical development participated in a contingency learning task. During this task, a robot provided reinforcement when the infant's right leg peak acceleration was above an individualized threshold. The correlation coefficient between the infant's performance and the change in quantity of right leg movement, linear variability, and nonlinear variability of right leg movement acceleration from baseline were calculated. Simple linear regression and multiple linear regression were calculated to explain the contribution of each variable to the performance individually and collectively. We found significant correlation between the performance and the change in quantity of right leg movement (r = 0.86, p < 0.001), linear variability (r = 0.71, p < 0.001), and nonlinear variability (r = 0.62, p = 0.004) of right leg movement acceleration, respectively. However, multiple linear regression showed that only quantity and linear variability of leg movements were significant predicting factors for the performance ratio (p < 0.001, adjusted R2 = 0.94). These results indicated that the quantity of exploration and variable exploratory strategies could be critical for the motor learning process during infancy.

AIM: Our purpose was to assess daily leg movement rate before and after a caregiver-provided in-home intervention for infants at risk for developmental disability. We also assessed adherence and quality of caregiver-child interaction.

METHODS: Twelve infants, at risk for developmental disabilities, and their caregivers participated in an intervention focused on increasing leg movements. Intervention started between 3- and 6-months corrected age and ended once the infant was able to sit independently or at 9 months corrected age, whichever occurred first. Infants were assessed monthly.

RESULTS: Infants at risk for developmental disabilities who were moving less than 1200 leg movements per hour awake at the start of the intervention increased their daily leg movement rate following the intervention (Median [range]: pre-1047 [506-1056], post- 1104 [655-1359], p = 0.040). Additionally, the caregivers had a high adherence (Median: 89%, Range: 11.43%-329.17%) and good quality of caregiver-child interaction (Median NCAST total: 46, Range: 34-59); and maintained similar amounts of adherence (p = 0.575) and quality of caregiver-child interaction (p = 0.432) throughout the intervention.

CONCLUSION: This study provides preliminary evidence that leg movement rate has the potential to be used as an outcome measure to assess an infant's progress and motor practice during an intervention.

BACKGROUND: Movement characteristics can differentiate between infants at risk and infants with typical development. However, it is unknown how many days are needed to accurately represent typical daily behavior for infants at risk of developmental disabilities when using wearable sensors. To consider the balance between participant burden and the amount of data collected and optimizing the efficiency of data collection, our study determined (1) how many days were necessary to represent typical movement behavior for infants at risk of developmental disabilities and (2) whether movement behavior was different on weekend days and weekdays.

METHODS: We used Opal wearable sensors to collect at least 5 days of 11 infants' leg movement data. The standard (average of 5 days) was compared with four methods (average of the first 1/2/3/4 days) using the Bland-Altman plots and the Spearman correlation coefficient. We also compared the data from the average of 2 weekend days to the average of the first 2 weekdays for 8 infants.

RESULTS: The Spearman correlation coefficient comparing the average of the first 2 days of data and the standards were all above 0.7. The absolute differences between them were all below 10% of the standards. The Bland-Altman plots showed more than 90% of the data points comparing the average of 2 days and the standards fell into the limit of agreement for each variable. The absolute difference between weekend days and weekdays for the leg movement rate, duration, average acceleration, and peak acceleration was 15.2%, 1.7%, 6.8% and 6.3% of the corresponding standard, respectively.

CONCLUSION: Our results suggest 2 days is the optimal amount of data to represent typical daily leg movement behavior of infants at risk of developmental disabilities while minimizing participant burden. Further, leg movement behavior did not differ distinctly across weekend days and weekdays. These results provide supportive evidence for an efficient amount of data collections when using wearable sensors to evaluate movement behavior in infants at risk of developmental disabilities.

Wearable sensors are being used to measure intensity of infant physical activity across full days. The variability of infant activity intensity within and across days is important to study given the potential impact of physical activity on developmental trajectories. Using retrospective data, we analyzed the intensity of leg movements in 10 typically-developing infants before and after naptimes. Leg movement data were captured from 20 minutes before and after multiple events of naps across seven days for each infant. We hypothesized that leg movement intensity would be lower before a nap than after a nap potentially due to lower arousal and increased fatigue prior to attaining sleep. However, our results showed that leg movement intensity was not significantly different when comparing the 20-minute period pre- and post-naps (F(1,7)=3.91, p=0.089, ηp 2=0.358). Our results are a first step in describing patterns of infant activity across days and highlights the need for further research regarding infant energy expenditure and physical activity.

BACKGROUND: Characteristics of movement can differentiate infants with typical development and infants with or at risk of developmental disabilities. We used wearable sensors to measure infants' typical movement patterns in the natural environment.

OBJECTIVE: Our objectives were to determine (1) how many days were sufficient to represent an infant's typical daily performance, and (2) if there was a difference in performance between weekdays and weekend days.

DESIGN: This was a prospective, observational study.

METHODS: We used wearable sensors to collect 7 consecutive days of data for leg movement activity, from 10 infants with typical development (1-5 months old). We identified each leg movement, and its average acceleration, peak acceleration, and duration. Bland-Altman plots were used to compare the standard (average of 7 days) with 6 options (1 day, the average of days 1 and 2, through the average of days 1 through 6). Additionally, the average of the first 2 weekdays was compared with the average of 2 weekend days.

RESULTS: The absolute difference between the average of the first 2 days and the standards fell below 10% of the standards (movement rate = 8.5%; duration = 3.7%; average acceleration = 2.8%; peak acceleration = 3.8%, respectively). The mean absolute difference between weekdays and weekends for leg movement rate, duration, average acceleration, and peak acceleration was 11.6%, 3.7%, 7.2%, and 7.3% of the corresponding standard.

LIMITATIONS: The small sample size and age range limit extrapolation of the results.

CONCLUSIONS: Our results suggest the best option is to collect data for 2 consecutive days and that movement did not differ between weekdays and weekend days. Our results will inform the clinical measurement of full-day infant leg movement for neuromotor assessment and outcome purposes.