Infants with sBPD are at greater risk for lifelong impairments in cognitive, language, academic achievement, executive, emotional, social and physical functioning when compared with infants without BPD [16]. Not only do infants with sBPD show delayed acquisition of many critical motor skills compared to age-specific norms, but these skills often develop atypically [6]. Occupational and physical therapy are recommended early for infants with BPD to address limitations in functional capacity, muscle strength, and motor function [17]. Negative trajectories of motor skill acquisition have also been shown to be more strongly and consistently associated with routine exposure to sedating medications than with the level of respiratory support [6]. There is undoubtedly a connection between respiratory function, neurodevelopment, medication exposure, and nutrition and growth that warrants further research.

Infancy and early childhood represent a period of life with both exquisite opportunity and vulnerability for neurodevelopment [18]. Physical and occupational therapy services promote the neurodevelopmental skills of hospitalized infants with sBPD but can be limited by medical instability. Optimal pulmonary function, brain growth, and development can only occur when these are properly balanced [12]. The BSRI Scale was developed to provide an objective measure of respiratory instability observed during developmentally appropriate activity. The Interaction domain is based on the knowledge that infants are able to visually engage with objects in their environment only when they have not exceeded the capacity of their respiratory system, as described previously by The Newborn Individualized Developmental Care and Assessment Plan (NIDCAP) [19]. The remaining four domains of the BSRI Scale incorporate knowledge of developmental movement patterns and breathing mechanics. The trunk maintains a dual role to support respiration and postural control [20]. Midline orientation of the head in the transverse plane is essential for postural control and motor skill development, including coordination of visual and upper extremities skills [19, 21]. Cervical extension may be seen in respiratory conditions, including BPD, because accessory muscles are recruited to support respiration [22]. Extension of the head reduces resistance by splinting large airways open to allow greater air flow, lower airway resistance, and decreased WOB [20]. Tachypnea, the single most sensitive sign of respiratory distress, is a compensatory mechanism for hypercarbia, hypoxemia, or acidosis, especially in neonates [23]. The final domain, WOB, includes excessive recruitment of accessory muscles in the neck, chest wall, or abdomen for respiration [23]. Grunting, stridor, wheezing and nasal flaring are subconscious attempts at decreasing airway resistance [4, 11, 24].

A published case study describes the conceptual framework and clinical application of the BSRI Scale for infants with BPD [25]. Since that time, an iterative process of repeat and review resulted in expert consensus on BSRI Scale domains and scoring criteria. Domains were adjusted slightly for continuity in skills through 1 year of corrected age. Scoring criteria were updated so that BSRI scores are ordinal in nature, with higher scores reflecting better performance and less respiratory instability. Additional descriptors were added to the criteria for scoring WOB. The length of time indicated to observe the testing items was clarified. Finally, updated criteria were added to score the Interaction and Midline domains as “observed” versus “not observed”. The remaining domains were scored based on the most persistent behavior observed during the assessment. Training using didactic content and case studies was developed to optimize the consistency of scoring among clinicians using the BSRI Scale. A copyright was obtained for the final version in 2016 (Supplemental Material 1).

Physical and occupational therapists have historically provided subjective information about infant capacity to participate in developmental activity. Standardized tools, such as the BSRI Scale, limit the subjective nature of assessment, enhancing the rigor of data provided by NICU therapists and allow longitudinal comparison. With standardized training, the therapists in this study achieved good to excellent inter-rater reliability for all domains of the revised BSRI Scale, including the total score. Optimally, information from the BSRI scale is shared with the interdisciplinary team to address the complex needs of this population.

No differences were found in the validity of the BSRI Scale between infants supported by NCPAP or NC. This was surprising as we had assumed that the need for NCPAP would reflect a greater underlying disease burden that would lead to poor tolerance of developmental activity. Given the small group sizes for NCPAP (n = 10) and NC (n = 14), these results are considered exploratory. Nonetheless, we speculate that the similarity in scores suggests that the infants were benefiting from the use of NCPAP, which provided them the respiratory stability to engage in developmentally appropriate activities. The BSRI scale could, therefore, be a useful tool to quantify developmental capacity by teams evaluating the impact of factors that affect developmental outcomes.

Our results indicate psychometric support for concurrent and construct validity of the BSRI Scale. Scores were inversely related to RSS scores, where lower BSRI scores and greater RSS scores both indicate greater respiratory instability. This may indicate that the BSRI Scale captures the respiratory stability of infants. Additionally, BSRI scores for infants with BPD were significantly lower than scores for infants without BPD, confirming our hypothesis. Unlike the RSS, the BSRI Scale is scored while the infant is performing functional activities. This adds meaningfully to NICU physical and occupational therapy practice because BSRI scores are a means of objective communication about capacity for participation in developmental activities among hospitalized infants with sBPD.

With standardized training, clinicians can reliably apply the BSRI Scale, and scores appear to reflect respiratory instability that may impact neurodevelopmental progress. For training and support for implementation of the BSRI, please contact the authors for available resources. The total score on the BSRI Scale can be tracked over time, reflecting the infant’s capacity to participate in developmental activity, during their NICU admission. The BSRI has the potential to be utilized in collaboration with an interdisciplinary medical team to provide clear and objective measure of developmental competence. This supports the ultimate goal of NICU therapy services: optimizing long term neurodevelopmental outcomes for hospitalized infants.

This study had a variety of limitations. The small sample size at a single institution limits generalizability. The BPD group had highly variables scores, which may have reduced our ability to detect a true difference between infants supported by NCPAP versus NC. Given the lack of statistical power, it is possible that we were unable to detect true differences between infants with BPD and those without. Including a large sample in a randomized, multicenter study is recommended for future research. Babies supported by mechanical ventilation were omitted from the study. Occupational and physical therapy services in the NICU can be initiated even when infants require high levels of respiratory support, including intubation. Use of the BSRI Scale among this population warrants further study. Finally, we hypothesize that supporting inpatient neurodevelopment will improve long term outcomes, yet we did not include that data as part of this study.