Barry Bodt

Adaptive treadmills (ATMs) that change speed based on the users’ gait mechanics can allow for healthy stride-to-stride variability observed during overground walking while maintaining the benefits of traditional treadmill training for gait rehabilitation. To enable unilateral modifications, the purpose of this study was to develop and validate an adaptive split-belt treadmill (sATM) that updates the speed of each belt of the treadmill based on the user’s propulsion and position to enable preferential targeting of unilateral gait mechanics. Fourteen young, healthy participants completed five trials at their comfortable walking speed on an existing tied-belt adaptive treadmill (ATM) and sATM with unilateral and bilateral modifications. The participants maintained similar propulsion and belt speeds between treadmills and belts for bilateral modifications. As a group, participants showed no change in propulsion and differences in walking speed for the unilateral modification, demonstrating successful enabling of unilateral modifications. Our results suggest that the sATM may require further tuning to encourage unilateral control strategies. The present study provided a proof of concept of a novel treadmill controller that can enable unilateral modifications, performed technical validation by demonstrating equivalence to an existing tied-belt ATM, and explored unilateral propulsion targeting to demonstrate unilateral modifications.

Background: A Just-in-Time Adaptive Intervention (JITAI) recognizes the dynamic nature of individuals’ states and contexts, predicts support needs, and sends tailored support at more opportune, actionable times. Objective: This paper outlines the application architecture and protocol for the pilot “Walking With Just-in-Time Adaptive Interventions” (WWJ) study, which uses a JITAI approach to improve walking behavior—duration, speed, and distance—and reduce stationary time, defined as idle sitting or standing. Methods: This study targets 20 adults who are physically inactive and leverages the Apple Watch to deliver fully automated tailored intervention notifications to “walk faster,” “walk longer,” or “stand up and move around” based on real-time data and contextual factors, including time-of-day activity patterns, geographic locations (eg, home, work, park, and gymnasium), weather conditions (eg, precipitation, wind speed, and humidity), and receptiveness. The protocol involves a preintervention assessment of demographics, behavior change constructs, anthropometrics, and resting vital signs; a 2-week observation period to establish walking behavior and stationary time baselines; a 2-week just-in-time learning period to evaluate receptiveness to untailored prompts at all applicable times; the 2-week JITAI intervention phase; and a postintervention assessment. Feasibility will be evaluated through protocol fidelity, participant adherence, Apple Watch wear-time compliance, user burden, acceptability ratings, and perceptions of benefits and preferences. Results: The WWJ architecture development began in spring 2021 and concluded in fall 2022. Participant recruitment and enrollment began in fall 2022. A total of 18 participants were recruited. Upon completion of the analyses, the results of this study are expected to be submitted for publication. Conclusions: Distinctively, the WWJ just-in-time learning period aims to train the learner based on user receptiveness within contexts by sending interventions whenever a participant meets the predetermined thresholds regardless of the likelihood that the user will be receptive to the notification to prune out nonopportune or “nonactionable” times. This approach may allow for greater customization during the JITAI period. International Registered Report Identifier (IRRID): DERR1-10.2196/79022

Objectives: The purpose of this study was to assess gait related dual task cost (DTC) changes over the course of a collegiate athletic career in both repetitive head impact (RHI) exposed and non-RHI exposed athletes. Setting: University Research Laboratory. Participants: We recruited 47 NCAA intercollegiate athletes and grouped by RHI exposed (N = 27) and non-RHI (N = 20) sports. Design: Participants completed 5 trials of single task (ST) and 5 trials of dual task (DT) gait with a working memory cognitive challenge both prior to their collegiate athletic careers (pre) and then again after they completed their collegiate athletic careers (post) (mean 1173 ± 341 days between tests) in this prospective longitudinal design. To assess for changes over the course of a career, separate 2 (group: RHI, non-RHI) × 2 (time: pre, post) mixed design ANOVA were performed for each dependent variable of interest (DTC gait velocity and DTC step length) and the model was adjusted for concussion history at the time of test and sex. Main Measures: Gait velocity and step length DTC. Results: There were no significant group by time interactions for DTC gait velocity (F = 0.517, P = .476, η2 = 0.012) or DTC step length ((F = 0.206, P = .652, η2 = 0.005). Conclusions: The primary finding of this study indicated no difference between RHI exposed and non-RHI exposed athletes gait DTC performance between the beginning and conclusion of their collegiate athletic careers. While the long-term effects of RHI remain to be fully determined, these results suggest that RHI may not adversely affect ST or DT gait performance when the individual is young.

BACKGROUND A Just-in-Time Adaptive Intervention (JITAI) recognizes the dynamic nature of individuals’ states and contexts, predicts support needs, and sends tailored support at more opportune, actionable times. OBJECTIVE This paper outlines the application architecture and protocol for the pilot “Walking With Just-in-Time Adaptive Interventions” (WWJ) study, which uses a JITAI approach to improve walking behavior—duration, speed, and distance—and reduce stationary time, defined as idle sitting or standing. METHODS This study targets 20 adults who are physically inactive and leverages the Apple Watch to deliver fully automated tailored intervention notifications to “walk faster,” “walk longer,” or “stand up and move around” based on real-time data and contextual factors, including time-of-day activity patterns, geographic locations (eg, home, work, park, and gymnasium), weather conditions (eg, precipitation, wind speed, and humidity), and receptiveness. The protocol involves a preintervention assessment of demographics, behavior change constructs, anthropometrics, and resting vital signs; a 2-week observation period to establish walking behavior and stationary time baselines; a 2-week just-in-time learning period to evaluate receptiveness to untailored prompts at all applicable times; the 2-week JITAI intervention phase; and a postintervention assessment. Feasibility will be evaluated through protocol fidelity, participant adherence, Apple Watch wear-time compliance, user burden, acceptability ratings, and perceptions of benefits and preferences. RESULTS The WWJ architecture development began in spring 2021 and concluded in fall 2022. Participant recruitment and enrollment began in fall 2022. A total of 18 participants were recruited. Upon completion of the analyses, the results of this study are expected to be submitted for publication. CONCLUSIONS Distinctively, the WWJ just-in-time learning period aims to train the learner based on user receptiveness within contexts by sending interventions whenever a participant meets the predetermined thresholds regardless of the likelihood that the user will be receptive to the notification to prune out nonopportune or “nonactionable” times. This approach may allow for greater customization during the JITAI period. INTERNATIONAL REGISTERED REPORT DERR1-10.2196/79022

Purpose: Intervertebral disc degeneration progresses with normal aging; yet common disc grading schemes do not account for age. Degeneration progression also varies between spine levels and is similarly not accounted for by current grading schemes. These limitations inhibit differentiation between discs with normal and expected aging (non-pathological) and discs with accelerated degeneration (which may be pathological). We sought to develop a statistical model to quantify normal age and spine level dependent disc degeneration. Methods: Eighty-four asymptomatic adult subjects ranging evenly from 18 to 83 years old underwent magnetic resonance imaging (MRI) of the lumbar spine. Subject traits, MRI-derived disc geometry, and MRI biomarkers of T2 relaxation time were evaluated and used to develop a statistical model to predict effective disc age, the age at which normal aging would produce a disc’s observed phenotype. Results: After evaluating several models, a 4-predictor model utilizing 1) subject height, 2) nucleus pulposus T2 relaxation time, 3) disc mid-sagittal area and 4) disc 3D volume, optimally estimated effective disc age. The effective age closely tracked true age for spine levels L1-L5 (R² ≈ 0.7, RMSE ≈ 10 years) and moderately tracked true age for L5-S1 (R² = 0.4, RMSE = 14 years). The uncertainty in the effective disc age prediction was ± 3 years as assessed by fivefold cross validation. Conclusion: We offer a data-driven, quantitative tool to quantify normal, expected intervertebral disc aging. This effective age model allows future research to target discs with accelerated degeneration.

Purpose: The retina-specific ABCA transporter, ABCA4, plays an essential role in translocating retinoids required by the visual cycle. ABCA4 genetic variants are known to cause a wide range of inherited retinal disorders, including Stargardt disease and cone-rod dystrophy. More than 1,400 ABCA4 missense variants have been identified; however, more than half of these remain variants of uncertain significance (VUS). The purpose of this study was to employ a predictive strategy to assess the pathogenicity of ABCA4 variants in inherited retinal diseases using protein modeling and computational approaches.Methods: We studied 13 clinically well-defined patients with ABCA4 retinopathies and identified the presence of 10 missense variants, including one novel variant in the ABCA4 gene, by next-generation sequencing (NGS). All variants were structurally analyzed using AlphaFold2 models and existing experimental structures of human ABCA4 protein. The results of these analyses were compared with patient clinical presentations to test the effectiveness of the methods employed in predicting variant pathogenicity.Results: We conducted a phenotype-genotype comparison of 13 genetically and phenotypically well-defined retinal disease patients. The in silico protein structure analyses we employed successfully detected the deleterious effect of missense variants found in this affected patient cohort. Our study provides American College of Medical Genetics and Genomics (ACMG)-defined supporting evidence of the pathogenicity of nine missense ABCA4 variants, aligning with the observed clinical phenotypes in this cohort.Conclusions: In this report, we describe a systematic approach to predicting the pathogenicity of ABCA4 variants by means of three-dimensional (3D) protein modeling and in silico structure analysis. Our results demonstrate concordance between disease severity and structural changes in protein models induced by genetic variations. Furthermore, the present study suggests that in silico protein structure analysis can be used as a predictor of pathogenicity and may facilitate the assessment of genetic VUS.

Purpose: To create and validate size guides for fitting Denovo (R) plain molar bands and bands with tubes to 3M (TM) ESPE (TM) stainless steel crowned primary molars. Methods: Two size guides were created for fitting these bands to corresponding crown sizes, with an additional pre-existing guide available for comparison. Eight volunteer dentists chose their best-fit band sizes for stainless steel crowned typodont teeth, with each seeing a subset of clinical conditions as determined by a randomized factorial experiment. Comparisons of dentists' best fits and each guide individually were evaluated for over 96 fits for robustness of clinical condition in an analysis of variance and agreement using intraclass correlation. Savings in attempted fits using size guides were estimated. Results: No significant differences over clinical conditions were observed when evaluating size guides and dentists' best fits. Intraclass correlations between plain band, plain band with tubes, and the pre-existing plain band with tubes guides and observed fits were 0.997, 0.998 and 0.998, respectively, with corresponding expected savings of 1.1, 0.7 and 0.5 attempts per fit, respectively. Conclusion: Size guides created for fitting plain bands and bands with tubes to stainless steel crowned primary molars were validated by volunteer dentists and showed promise for decreasing waste and increasing efficiency during dental visits.

Opioid use disorder (OUD) during pregnancy has risen in the U.S. over the past two decades, resulting in a growing number of children with intrauterine opioid exposure (IOE). Limited research exists supporting best practices to optimize primary care for these children and their families, particularly mothers with OUD. Using a modified Delphi method, we surveyed pediatric primary care clinicians from a single children’s health care system regarding their experiences in caring for this population. In Phase 1, open-ended survey questions inquired about needs and challenges facing these infants, their families, and clinicians and resources within primary care. After thematic analysis, the most frequent responses were presented as a Phase 2 survey for clinicians to select their top five. Percentages for the most commonly selected top five themes were tabulated. Survey response rates were 58/139 (42%) for Phase 1 and 45/137 (33%) for Phase 2. For infants with IOE and their families, respondents identified parenting knowledge and family issues related to maternal OUD as top challenges, with limited resources to address them in primary care. Clinicians identified time constraints and follow-up issues as top challenges. Future intervention in pediatric primary care could include addressing parenting education, resource gaps, and best practice recommendations in caring for children with IOE.