Gary E. Strangman

Objective. Sensing modalities for cuffless blood pressure (BP) monitoring remain insufficiently characterized. To address this, we used exploratory data analysis (EDA) to evaluate multimodal physiological signals’ associations with reference BP, to gain insight into their BP-related information and characteristics. Approach. Time-synchronized electrocardiogram, photoplethysmography (PPG), and superficial temporal artery tonometry (STAT) signals were collected from 28 sessions across 9 healthy participants during resting and handgrip-induced BP perturbations, referenced against continuous Finapres BP. Pulse transit time (PTT)/PPG intensity ratio (PIR)-derived and STAT-derived BP estimates were evaluated via participant-level Pearson correlation and φ _k coefficients, dynamic-responsiveness/baseline-stability measures, and a phase-resolved (stable vs dynamic) analysis. Main results. PTT/PIR-derived estimates showed weak linear association with reference SBP ( r ≈ 0.37–0.41) and weaker association with diastolic BP (DBP), with nonlinear association ( φ _k ≈ 0.58–0.62 SBP, 0.38–0.57 DBP) exceeding their linear correlation. STAT-derived estimates showed very weak linear correlation but the strongest nonlinear association ( φ _k ≈ 0.68 SBP, 0.71 DBP)—modest for systolic BP but more pronounced for DBP. Phase-resolved analysis confirmed STAT tracked BP more closely during the dynamic (handgrip) phase and PTT/PIR during the stable phase, a genuine, phase-specific pattern rather than a pooling artifact; because Finapres can amplify beat-to-beat amplitude, this should be read relative to that reference, not invasive BP. Significance. These complementary properties motivate a fusion strategy using STAT to track rapid BP changes while PTT/PIR anchors the baseline. More broadly, this EDA-derived understanding can guide more data-efficient, interpretable models—properties clinicians require regardless of data volume. Given the modest, healthy-only sample, findings should be regarded as preliminary.

UNSTRUCTURED This study demonstrates that it is highly feasible to recruit and retain surgical patients across the aging and cognitive spectra for continuous perioperative neuromonitoring using NINscan, a multimodal wearable device originally developed for spaceflight.

Objective: Continuous monitoring of blood pressure (BP) is a key parameter for cardiovascular assessment and hemodynamics monitoring. Current noninvasive methods are limited by frequent calibration, motion and environmental artifacts, and delayed response to rapid BP changes. In perioperative and critical-care settings, even short-duration hypotensive episodes and rapid BP lability have been associated with adverse outcomes, motivating technologies with high temporal fidelity. This study introduces a noninvasive blood pressure monitoring technique using superficial temporal artery tonometry (STAT), which employs a biomechanics-based transfer function to improve accuracy, reduce calibration requirements, and detect rapid BP changes in dynamic conditions. Methods: Twenty-nine recording sessions of continuous BP monitoring were collected in human subjects ($n=10$) during rest and during handgrip-induced BP fluctuations. Measurements were recorded simultaneously using the STAT method and compared to a noninvasive reference device (Finapres/Finometer volume-clamp) and Pulse Transit Time (PTT) baseline (derived from timing features) method. Results: Using the Finapres/Finometer as a noninvasive reference, our method achieved a mean absolute difference (MAD) of $4.8 \pm 2.2$ mmHg during rest and $6.5 \pm 3.4$ mmHg during handgrips, significantly outperforming PTT, especially under dynamic conditions. Conclusion: BP monitoring with STAT and its biomechanics-based transfer function achieved improved detection of rapid BP fluctuations, and higher accuracy than PTT under dynamic conditions. Significance: STAT with biomechanics-based modeling enables real-time, robust noninvasive BP monitoring, overcoming calibration, motion, and detection limitations of current methods.

Virtual Reality (VR)-based sensory stimulation can provide relaxation and psychological restoration in isolated, confined and extreme conditions such as long-duration spaceflight, but it remains unclear which aspects of VR would be most beneficial. To investigate individual preferences for various VR attributes, 25 overwintering crew members at the Amundsen-Scott South Pole Station in Antarctica underwent 16 variations of VR stimulation at the end of their mission, with manipulations in delivery mode (VR vs. laptop), content (nature vs. city environments), duration (4 vs. 10 min), and sensory augmentation (with or without temperature cues). Data collection included pre- and post-intervention surveys on perceived quality (value, immersiveness, restorativeness) and mood, as well open-ended qualitative feedback. We found that VR was viable and restorative in a high-fidelity spaceflight analog. Although longer-lasting nature scenes were preferred overall, interindividual variation in preferences for sensory stimulation emphasizes the need for a personalized approach.

Purpose: This study aimed to investigate how four types of successfully executed, legal front-on, one-on-one torso tackles influence the tacklers’ and ball carriers’ inertial head kinematics. Methods: A total of 455 successful front-on, one-on-one torso tackle trials completed by 15 rugby code players using three-dimensional motion capture were recorded. Tackles differed with respects to the height of the contact point on the ball carrier’s torso. A series of mixed general linear models were conducted. Results: The tackler sustained the highest peak resultant linear (P < 0.001) and angular (P < 0.01) head accelerations when contacting the lower torso to execute a “dominant” tackle compared with mid or upper torso, although these latter tackle types had the lowest ball carrier inertial head kinematics. When executing a “smother” tackle technique, a significant decrease in peak resultant linear head acceleration was observed with a vertical “pop” then lock action used, compared with the traditional upper torso tackling technique (P < 0.001). Conclusions: Modifying the tackler’s engagement with a ball carrier’s torso, with respect to height and technical execution, alters the inertial head kinematics of the tackler and the ball carrier. The traditional thinking about optimal tackle technique, as instructed, may need to be reevaluated, with the midtorso being a potential alternative target contact height, whereas changes in tackle execution may be relatively protective for tacklers when executing either a dominant or smother tackle. This study provides critical scientific evidence to underpin revised coaching tackling technique interventions that might enhance player safety. Tackles in which the tackler contacts the ball carrier around the midtorso region, rather than lower torso, produce the lowest acceleration and thus may contribute to reducing head injury risk for the tackler.

Lee W, et al. Brain Neurorehabil. 2021 Mar;14(1):e4. https://doi.org/10.12786/bn.2021.14.e4

In this paper we investigate the potential of generic physiological features of stress resilience in predicting air traffic control (ATC) candidates' performance in a highly-stressful low-fidelity ATC simulator scenario. Stress resilience is highlighted as an important occupational factor that influences the performance and well-being of air traffic control officers (ATCO). Poor stress management, besides the lack of skills, can be a direct cause of poor performance under stress, both in the selection process of ATCOs and later in the workplace. 40 ATC candidates, within the final stages of their selection process, underwent a stimulation paradigm for elicitation and assessment of various generic task-unrelated physiological features, related to resting heart rate variability (HRV) and respiratory sinus arrhythmia (RSA), acoustic startle response (ASR) and the physiological allostatic response, which are all recognized as relevant psychophysiological markers of stress resilience. The multimodal approach included analysis of electrocardiography, electromyography, electrodermal activity and respiration. We make advances in computational methodology for assessment of physiological features of stress resilience, and investigate the predictive power of the obtained feature space in a binary classification problem: prediction of high- vs. low-performance on the developed ATC simulator. Our novel approach yields a relatively high 78.16% classification accuracy. These results are discussed in the context of prior work, while considering study limitations and proposing directions for future work.