Objectives: Traumatic stress symptoms from multiple causes are endemic among impoverished women who are also at high risk for delivering infants requiring neonatal intensive care unit (NICU) care, but whether this event itself constitutes a distinct traumatic stress trigger is unknown. Previous research does suggest having an infant in the NICU generates traumatic stress among white middle-class mothers, stress that can impact their infant’s behavior and development. This study evaluated the prevalence of acute posttraumatic stress symptoms among low-income mothers of infants admitted to the NICU compared with similar mothers with infants in the well baby nursery (WBN). Methods: A total of 59 NICU and 60 WBN mothers were recruited from the Boston Medical Center. Within the first week after birth, all participants were assessed for postpartum acute posttraumatic stress and depression symptoms and asked about lifetime traumatic events before the birth of their baby. The acute posttraumatic stress symptoms were analyzed as a continuous variable and whether they reached the categorical severity criteria for acute stress disorder. Results: NICU mothers show increased symptoms of acute posttraumatic stress and depression. Twenty-three percent of NICU and 3% of WBN reached severity criteria for acute stress disorder. When controlling for relevant covariates, having a newborn in the NICU had a significant association with the number of mothers’ acute posttraumatic stress symptoms not fully explained by their symptoms of depression or prior lifetime history of traumatic events. Conclusions: Addressing acute posttraumatic stress symptoms may enhance interventions to help urban families of NICU infants.

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.

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.