Accelerometer Thresholds for Estimating Physical Activity Intensity Levels in Infants: A Preliminary Study.

Lack of physical activity (PA) at a young age can result in health issues. Thus, monitoring PA is important. Wearable accelerometers are the preferred tool to monitor PA in children. Validated thresholds are used to classify activity intensity levels, e.g., sedentary, light, and moderate-to-vigorous, in ambulatory children. No previous work has developed accelerometer thresholds for infancy (pre-ambulatory children). Therefore, this work aims to develop accelerometer thresholds for PA intensity levels in pre-ambulatory infants. Infants (n = 10) were placed in a supine position and allowed free movement. Their movements were synchronously captured using video cameras and accelerometers worn on each ankle. The video data were labeled by activity intensity level (sedentary, light, and moderate-to-vigorous) in two-second epochs using observational rating (gold standard). Accelerometer thresholds were developed for acceleration and jerk using two optimization approaches. Four sets of thresholds were developed for dual (two ankles) and for single-worn (one ankle) accelerometers. Of these, for a typical use case, we recommend using acceleration-based thresholds of 1.00 m/s to distinguish sedentary and light activity and 2.60 m/s to distinguish light and moderate-to-vigorous activity. Acceleration and jerk are both suitable for measuring PA.

Associations between EEG power and coherence with cognition and early precursors of speech and language development across the first months of life.

The neural processes underpinning cognition and language development in infancy are of great interest. We investigated EEG power and coherence in infancy, as a reflection of underlying cortical function of single brain region and cross-region connectivity, and their relations to cognition and early precursors of speech and language development. EEG recordings were longitudinally collected from 21 infants with typical development between approximately 1 and 7 months. We investigated relative band power at 3-6Hz and 6-9Hz and EEG coherence of these frequency ranges at 25 electrode pairs that cover key brain regions. A correlation analysis was performed to assess the relationship between EEG measurements across frequency bands and brain regions and raw Bayley cognitive and language developmental scores. In the first months of life, relative band power is not correlated with cognitive and language scales. However, 3-6Hz coherence is negatively correlated with receptive language scores between frontoparietal regions, and 6-9Hz coherence is negatively correlated with expressive language scores between frontoparietal regions. The results from this preliminary study contribute to the existing literature on the relationship between electrophysiological development, cognition, and early speech precursors in this age group. Future work should create norm references of early development in these domains that can be compared with infants at risk for neurodevelopmental disabilities.

Similar early intervention referral rates following in-person administration of the Bayley Scales of Infant and Toddler Development, 4th Edition versus Telehealth Administration of the Developmental Assessment in Young Children, 2nd Edition in the high-risk infant population.

BACKGROUND: Infants with prematurity, low birthweight, and medical comorbidities are at high risk for developmental delays and neurodevelopmental disabilities and require close monitoring. Due to the COVID-19 pandemic, high-risk infant follow-up (HRIF) programs have adapted to perform developmental assessments via telehealth. OBJECTIVES: Describe the referral rates to initiate, continue, or increase/add early intervention (EI) therapies based on in-person use of the Bayley Scales of Infant and Toddler Development, 4th Edition (BSID-IV) or telehealth use of the Developmental Assessment in Young Children, 2nd Edition (DAYC-2). METHODS: A retrospective chart review was conducted on 203 patients seen in the HRIF program at an academic medical center in Southern California. Patients were divided into in-person (BSID-IV) and telehealth (DAYC-2) assessment groups. Statistical analyses were performed to describe demographic characteristics, medical information, and referral rates for EI therapies by the types of visits. RESULTS: The in-person and telehealth groups demonstrated similar demographic and clinical characteristics and comparable referral rates for initiating EI therapies. Telehealth patients already receiving therapies were recommended to increase/add EI therapies at a higher rate compared to in-person patients. CONCLUSIONS: The BSID-IV is widely used to assess for developmental delays in the high-risk infant population, but in-person administration of this tool poses limitations on its accessibility. Telehealth administration of an alternative tool, such as the DAYC-2, can lead to similar EI referral rates as in-person administration of the BSID-IV. Increased use of telehealth developmental assessments can promote timely detection of developmental delays and minimize gaps in healthcare access.

Early full-day leg movement kinematics and swaddling patterns in infants in rural Guatemala: A pilot study.

BACKGROUND: Tools to accurately assess infants' neurodevelopmental status very early in their lives are limited. Wearable sensors may provide a novel approach for very early assessment of infant neurodevelopmental status. This may be especially relevant in rural and low-resource global settings. METHODS: We conducted a longitudinal observational study and used wearable sensors to repeatedly measure the kinematic leg movement characteristics of 41 infants in rural Guatemala three times across full days between birth and 6 months of age. In addition, we collected sociodemographic data, growth data, and caregiver estimates of swaddling behaviors. We used visual analysis and multivariable linear mixed models to evaluate the associations between two leg movement kinematic variables (awake movement rate, peak acceleration per movement) and infant age, swaddling behaviors, growth, and other covariates. RESULTS: Multivariable mixed models of sensor data showed age-dependent increases in leg movement rates (2.16 [95% CI 0.80,3.52] movements/awake hour/day of life) and movement acceleration (5.04e-3 m/s2 [95% CI 3.79e-3, 6.27e-3]/day of life). Swaddling time as well as growth status, poverty status and multiple other clinical and sociodemographic variables had no impact on either movement variable. CONCLUSIONS: Collecting wearable sensor data on young infants in a rural low-resource setting is feasible and can be used to monitor age-dependent changes in movement kinematics. Future work will evaluate associations between these kinematic variables from sensors and formal developmental measures, such as the Bayley Scales of Infant and Toddler Development.

Associating neuromotor outcomes at 12 months with wearable sensor measures collected during early infancy in rural Guatemala.

BACKGROUND: Sensitive measures to predict neuromotor outcomes from data collected early in infancy are lacking. Measures derived from the recordings of infant movement using wearable sensors may be a useful new technique. METHODS: We collected full-day leg movement of 41 infants in rural Guatemala across 3 visits between birth and 6 months of age using wearable sensors. Average leg movement rate and fuzzy entropy, a measure to describe the complexity of signals, of the leg movements' peak acceleration time series and the time series itself were derived. We tested the three measures for the predictability of infants' developmental outcome, Bayley Scales of Infant and Toddler Development III motor, language, or cognitive composite score assessed at 12 months of age. We performed quantile regressions with clustered standard errors, accounting for the multiple visits for each infant. RESULTS: Fuzzy entropy was associated with the motor composite score at the 0.5 quantiles; this association was not found for the other two measures. Also, no leg movement characteristic was associated with language or cognitive composite scores. CONCLUSION: We propose that the entropy of leg movement associated peak accelerations calculated from the wearable sensor data collected for a full-day can be considered as one predictor for infants' motor developmental outcome assessed with Bayley Scales of Infant and Toddler Development III at 12 months of age.