Immediate Effect of Wearable Balance Training Device on Muscle Co-contraction and Postural Control During Standing.

Postural control is one of the primary body functions for fall prevention. Unexpected perturbation-based balance training is effective for improving postural control. However, the effect of perturbation-based training using assistive devices on muscle activity and co-contraction for standing balance is still unclear. This training is also difficult to perform easily because it requires large instruments or expert guidance. The purpose of this study is to demonstrate the effect of perturbation-based balance training using a wearable balance training device (WBTD) on postural control. In this study, fourteen healthy young adult males were assigned to either a WBTD group or a sham group. In the intervention session, participants in the WBTD group were perturbed either left or right direction at random timing by the WBTD during tandem stance balance training. Participants in the Sham group did not receive external perturbation during tandem stance balance training. Before and after the intervention session, participants of both groups underwent unexpected lateral perturbation postural control testing (pre- and post-test). The normalized integral of electromyography (IEMG), co-contraction index (CCI), and center of pressure (COP) parameters were measured in the pre- and post-test. Experimental results showed that the WBTD group in the post-test significantly decreased left Gluteus Medius IEMG, CCI of both Gluteus Medius, and peak COPML velocity, compared to those of the pre-test (p < 0.001, p = 0.024, p = 0.031, respectively). We conclude that balance training using WBTD could improve flexible postural control adjustment via cooperative muscle activation.

Perturbation-Based Balance Exercise Using a Wearable Device to Improve Reactive Postural Control.

Reactive postural control is an important component of the balance function for fall prevention. Perturbation-based balance exercises improve reactive postural control; however, these exercises require large, complex instruments and expert medical guidance. This study investigates the effects of unexpected perturbation-based balance exercises using a wearable balance exercise device (WBED) on reactive postural control. Eighteen healthy adult males participated in this study. Participants were assigned to the WBED and Sham groups. In the intervention session, participants in the WBED group randomly underwent unexpected perturbation in the mediolateral direction, while the Sham group performed the same exercises without perturbation. Before and after the intervention session, all participants underwent evaluation of reactive balance function using air cylinders. Peak displacement (D), time at peak displacement (T), peak velocity (V), and root mean square (RMS) of center of pressure (COP) data were measured. For mediolateral and anteroposterior COP (COPML and COP[Formula: see text]), the main effects of group and time factors (pre/post) were investigated through the analysis of variance for split-plot factorial design. In the WBED group, the D-COPML and V-COPML of the post-test significantly decreased compared to those of the pre-test (p = 0.017 and p = 0.003, respectively). Furthermore, the D-COPAP and RMSAP of the post-test significantly decreased compared to those of the pre-test (p = 0.036 and p = 0.015, respectively). This study proved that the perturbation-based balance exercise using WBED immediately improved reactive postural control. Therefore, wearable exercise devices, such as WBED, may contribute to the prevention of falls and fall-related injuries.

Neurotypicals with higher autistic traits have delayed visual processing of an approaching life-sized avatar's gait: an event-related potentials study.

Introduction: Autism spectrum disorder (ASD) is a neurodevelopmental disorder, which is reportedly related to difficulties in the visual processing of human motion, such as biological motion and gestures. Moreover, neurotypical (here, we mention it as individuals without a diagnosis) adults with autistic traits are clumsier than those without autistic traits when passing by others. It is still unclear whether the clumsiness derived from atypical visual processing of another's approaching gait motion. We aim to address this question by investigating the association between autistic traits in neurotypical adults and the visual processing of an approaching life-sized avatar's gait. Methods: We clarified a typical visual motion processing and autistic traits in daily life in 26 neurotypical adults by analyzing the subthreshold autism trait questionnaire (SATQ) score, a 24-item self-report scale of ASD, and event-related potentials (ERPs) in response to walking motion of a passing avatar. Videos of walking life-sized virtual avatars approaching and retreating were presented as visual stimuli. Results and discussion: The association between the participants' SATQ scores and the latencies and amplitudes of the ERPs was examined. ERP components (N170 and P200) components were identified at T5 and T6 electrodes. Participants reporting higher SATQ scores had longer latencies of P200 at T6 and lower amplitudes of P200 at T5 and T6 electrodes for the approaching avatar than those reporting lower SATQ scores. These findings indicate that adults with autistic traits have delayed and less sensitive visual processing of the approaching avatar. It suggests that while passing another person, these individuals have atypical visual processing of their approach. This study may contribute to elucidating autistic traits from the perspective of visual processing in an environment simulating daily life.

Changes in Cerebral Hemodynamics During Systemic Pulmonary Shunt and Pulmonary Artery Banding in Infants with Congenital Heart Disease.

Palliative surgery is often performed in the treatment of congenital heart disease. Two representative palliative procedures are the systemic pulmonary shunt and pulmonary artery banding. Dramatic changes in cerebral hemodynamics may occur in these operations due to changes in the pulmonary-to-systemic blood flow ratio and systemic oxygenation. However, there seem to be almost no studies evaluating them. Accordingly, we evaluated cerebral perfusion by transcranial Doppler ultrasonography and cerebral oxygenation by near infrared spectroscopy during these procedures. In the post hoc analysis of a previous prospective observational study, cerebral blood flow velocities of the middle cerebral artery measured by transcranial Doppler were compared between the start and end of surgery as were the pulsatility index and resistance index. The cerebral oxygenation values were also compared between the start and end of surgery. Twenty-two infants with systemic pulmonary shunt and 20 infants with pulmonary artery banding were evaluated. There were no significant differences of the flow velocities between the start and end of surgery in either procedure. The pulsatility index significantly increased after pulmonary artery banding, which may compete with the increase in cerebral perfusion due to the increase in systemic blood flow. The cerebral oxygenation decreased in both procedures, possibly due to an increase in body temperature. Arterial oxygen saturation was almost the same before and after both procedures. Contrary to our expectation, the changes in cerebral hemodynamics in the palliative operations were small if the management of physiological indices such as arterial oxygen saturation was properly performed during the procedures.

Verification of gait analysis method fusing camera-based pose estimation and an IMU sensor in various gait conditions.

A markerless gait analysis system can measure useful gait metrics to determine effective clinical treatment. Although this gait analysis system does not require a large space, several markers, or time constraints, it inaccurately measure lower limb joint kinematics during gait. In particular, it has a substantial ankle joint angle error. In this study, we investigated the markerless gait analysis method capability using single RGB camera-based pose estimation by OpenPose (OP) and an inertial measurement unit (IMU) sensor on the foot segment to measure ankle joint kinematics under various gait conditions. Sixteen healthy young adult males participated in the study. We compared temporo-spatial parameters and lower limb joint angles during four gait conditions with varying gait speeds and foot progression angles. These were measured by optoelectronic motion capture, markerless gait analysis method using OP, and proposed method using OP and IMU. We found that the proposed method using OP and an IMU significantly decreased the mean absolute errors of peak ankle joint angles compared with OP in the four gait conditions. The proposed method has the potential to measure temporo-spatial gait parameters and lower limb joint angles, including ankle angles, in various gait conditions as a clinical settings gait assessment tool.

Gait Perception of Life-Size Point-Light Walker is Associated with Autistic Traits: Evidence from Event-Related Evoked Potentials.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by a combination of atypicalities in social cognition. Previous studies showed that people with autistic traits have atypicality in motion perception on a point-light display by measuring visual event-related potentials (ERPs). Although some studies have focused on the association between motion perception and autistic traits, visual ERPs to biological motion as large as actual person have not been investigated. Measuring brain activity in a real-life environment help us to understand the difficulties showed in daily life by people with autistic traits. In this study, we investigated the association between gait perception and autistic traits by measuring ERPs during video observation of approaching and receding life-sized point-light walkers (PLW s). ERPs were measured using an 8-channel EEG system in 22 adults. The multiple regression analyses were conducted to assess association between the Subthreshold Autism Trait Questionnaire (SATQ) score and the ERP amplitude or latency. As the results, we found that the higher SATQ score could be explained by the longer latency of N1 on the occipitotemporal area. These findings suggested that people with autistic traits have difficulty in perceiving the approach of others in daily life.

Age Difference of the Relationship Between Cerebral Oxygen Saturation and Physiological Parameters in Pediatric Cardiac Surgery with Cardiopulmonary Bypass: Analysis Using the Random-Effects Model.

Recently, monitoring of cerebral oxygen saturation (ScO2) has become widespread in pediatric cardiac surgery. Our previous study reported that mean blood pressure (mBP) was the major contributor to ScO2 throughout cardiac surgery with cardiopulmonary bypass (CPB) in children weighing under 10 kg. We speculated that this result might be attributable to incomplete cerebral autoregulation in such young children. Accordingly, our hypothesis is that the relationship between ScO2 and the physiological parameters may change according to the growth of the children. ScO2 was measured with an INVOS 5100C (Somanetics, Troy, MI). Random-effects analysis was employed with ScO2 as a dependent variable, and seven physiological parameters (mBP, central venous pressure, nasopharyngeal temperature, SaO2, hematocrit, PaCO2, and pH) were entered as independent covariates. The analysis was performed during the pre-CPB, CPB, and post-CPB periods by dividing the patients into two groups: infants (Infant Group) and children who were more than 1 year old (Child Group). The Infant and Child Groups consisted of 28 and 21 patients. In the random-effects analysis, mBP was the major contributor to ScO2 during CPB in both groups. During the pre-CPB period, the effect of mBP was strongest in the Infant group. However, its effect was second to that of SaO2 in the Child Group. During the post-CPB period, SaO2 and mBP still affected ScO2 in the Infant group. However, the dominant contributors were unclear in the Child Group. Cerebral autoregulation may be immature in infants. In addition, it may be impaired during CPB even after 1 year of age.

Accuracy of Temporo-Spatial and Lower Limb Joint Kinematics Parameters Using OpenPose for Various Gait Patterns With Orthosis.

A cost-effective gait analysis system without attachments and specialized large environments can provide useful information to determine effective treatment in clinical sites. This study investigates the capability of a single camera-based pose estimation system using OpenPose (OP) to measure the temporo-spatial and joint kinematics parameters during gait with orthosis. Eleven healthy adult males walked under different conditions of speed and foot progression angle (FPA). Temporo-spatial and joint kinematics parameters were measured using a single camera-based system with OP and a three-dimensional motion capture system. The limit of agreement, mean absolute error, absolute agreement (ICC2, 1), and relative consistency (ICC3, 1) between the systems under each condition were assessed for reliability and validity. The results demonstrated that most of the ICC for temporo-spatial parameters and hip and knee kinematics parameters were good to excellent (0.60 - 0.98). Conversely, most of the ICC for ankle kinematics in all conditions were poor to fair (< 0.60). Thus, the gait analysis using OP can be used as a clinical assessment tool for determining the temporo-spatial, hip, and knee sagittal plane angles during gait.

3D Body Parts Tracking of Mouse Based on RGB-D Video from Under an Open Field.

The mouse is a valuable animal model to address the neural mechanism of higher brain function and test the pharmacodynamics of new drugs. The development of novel behavioral analysis to detect subtleties of emotion is valuable for the evolution of neuroscience research and drug discovery. 3D pose estimation is expected to contribute significantly to them. Several methods for 3D pose estimation of the mouse using optical motion capture with markers and multiple cameras have been proposed, but these methods have problems such as preparing marker sets and the influence of the markers on mouse behavior. A low-cost and simple method for markerless 3D pose estimation of the mouse using a single RGB-D (Depth) camera is proposed. As a result, the proposed method improved the accuracy of limbs tracking compared to existing limbs tracking methods. In addition, this method could track other body parts (nose, base of tail) and the center of gravity.Clinical Relevance-This study could contribute to the development of neuroscience research and drug discovery by clarifying the relationship between subtle changes in mouse behavior and emotional movements.

The Relationships of Cerebral and Somatic Oxygen Saturation with Physiological Parameters in Pediatric Cardiac Surgery with Cardiopulmonary Bypass: Analysis Using the Random-Effects Model.

Recently, tissue oxygenation in pediatric heart surgery is measured by using near-infrared spectroscopy. Monitoring of cerebral oxygen saturation (ScO2) is most common but that of somatic tissue oxygen saturation (SrO2) is also gradually becoming widespread. However, the value of their monitoring is not well established. One of the reasons for this may be that the physiological factors affecting ScO2 and SrO2 have not been sufficiently clarified. Accordingly, we prospectively observed the changes in ScO2 and SrO2 simultaneously throughout cardiac surgery with cardiopulmonary bypass (CPB) in children weighing under 10 kg and evaluated their relationships with physiological parameters by using the random-effects model. ScO2 and SrO2 were measured with an INVOS 5100C (Somanetics, Troy, MI, USA). The random-effects analysis was applied for ScO2 and SrO2, as dependent variables, and seven physiological parameters (mean blood pressure, central venous pressure, rectal temperature, SaO2, hematocrit PaCO2, and pH) were entered as independent covariates. The analysis was performed during the pre-CPB, CPB, and post-CPB periods. Next, the same analysis was performed by dividing the patients into univentricular and biventricular physiological types. Forty-one children were evaluated. Through the whole surgical period, ScO2 correlated strongly with mean blood pressure regardless of the physiological type. On the other hand, the contribution of mean blood pressure to SrO2 was weak and various other parameters were related to SrO2 changes. Thus, the physiological parameters affecting ScO2 and SrO2 were rather different. Accordingly, the significance of monitoring of cerebral and somatic tissue oxygen saturation in pediatric cardiac surgery should be further evaluated.

Effect of Varying Soft Actuator Band Positions of a Wearable Assist Device on Gait Simulation of Lower Limb Muscle Force.

The purpose of this study is to investigate the effect of changing the application points and directions of the soft actuator band of a wearable hip assist device on muscle force and joint kinematics during gait. Healthy adult participants walked under four conditions with varying band positions of a soft wearable hip assist device. The three-dimensional coordinates of markers and ground reaction force data were measured during gait. Lower limb muscle forces and joint angles were calculated using a musculoskeletal model. Our results showed that the position and running direction of the soft actuator band decreased the forces of the iliopsoas and hamstring muscles.

Effects of Varying Plantarflexion Stiffness of Ankle-Foot Orthosis on Achilles Tendon and Propulsion Force During Gait.

An ankle-foot orthosis (AFO) with a plantarflexion resistance function, improves post-stroke gait. An AFO with a plantarflexion resistance function not only affects the first rocker function and the weight acceptance but also the late stance phase. Achilles tendon extension is important for ankle joint function and for forward propulsion during the late stance phase; however, the effect of an AFO with a plantarflexion resistance function on the Achilles tendon is unclear. The purpose of this study was to investigate the effect of plantarflexion resistance on the extension of the Achilles tendon and the forward-propulsive force. Herein, 10 healthy adult males participated who walked under three different conditions: a no-AFO condition and two AFO conditions that had different levels of plantarflexion resistance (P1 and P2). The stiffness value of the P1 and P2 conditions was 0.56 and 1.47 Nm/°, respectively. A three-dimensional (3D) motion analysis system and a musculoskeletal model were used to assess the tendon-length change, the ground reaction force, kinematics, and kinetics data. The change in Achilles tendon length was significantly lower in the P1 and P2 conditions than the no-AFO condition. Furthermore, changes in the length of the Achilles tendon significantly decreased in the P2 condition when compared with that in the P1 condition. The peak anterior ground reaction force was significantly lower in the P2 condition than the no-AFO condition. These results suggest that excessive assist provided by an AFO prevents efficient gait by decreasing both the forward-propulsive force and tendon function.

Two-stage goal-directed therapy protocol for non-donor open hepatectomy: an interventional before-after study.

PURPOSE: Hemodynamic management during low central venous pressure (L-CVP)-assisted hepatectomy involves fluid restriction during resection and fluid resuscitation after resection. Recently, high stroke volume variation (SVV) has been reported as an alternative to L-CVP for reducing blood loss during a hepatectomy. The current study evaluated the impact of a newly implemented SVV-based goal-directed therapy (GDT) protocol on blood loss during hepatectomy. METHODS: We conducted a before-after comparative study, which included L-CVP-assisted hepatectomy cases (control group) and GDT-assisted hepatectomy cases (intervention group). The GDT protocol included SVV, cardiac index, and mean arterial pressure as hemodynamic parameters. The target SVV ranges were ≥ 13% and ≤ 12% before and after the resection, respectively. The primary endpoint was the proportion of patients whose blood loss was < 400 mL (median of our hepatectomy cases) in the GDT group, and it was compared to a predefined threshold of 50%. We also investigated factors associated with blood loss using multiple regression analysis. RESULTS: We included 66 patients in the control group and 50 in the GDT group. In the GDT group, the median blood loss was 220 mL and 36 patients (72%) lost < 400 mL blood. This was significantly greater than 50% (P < 0.001). Post-resection GDT-guided fluid optimization reduced positive intraoperative fluid balance compared to that achieved by the conventional fluid therapy used in the control. Multiple regression analysis showed that GDT application, epidural anesthesia, operative time, and hydroxyethyl-starch infusion volume were associated with blood loss. CONCLUSION: Compared to conventional management, SVV-guided GDT may reduce blood loss during hepatectomies.

Changes of Cerebral Blood Volume During Robot-Assisted Laparoscopic Radical Prostatectomy: Observational Prospective Study Using Near-Infrared Time-Resolved Spectroscopy.

Purpose: Robot-assisted laparoscopic radical prostatectomy (RARP) requires a steep head-down tilt and pneumoperitoneum, which may cause an increase in cerebral blood volume (CBV). With a new near-infrared time-resolved spectroscopy device, the tNIRS-1, we can measure the absolute value of the cerebral hemoglobin concentration and hence calculate CBV and cerebral oxygen saturation (rSO2). Using this device, we evaluated the time course of CBV during surgery and also evaluated the changes in rSO2 simultaneously. Materials and Methods: We performed a prospective observational study of 21 patients scheduled for RARP. We evaluated CBV and rSO2 by using the tNIRS-1 at 10 time points during surgery. Results: The CBV was 2.92 ± 0.38 mL ·100 g-1 after the end of anesthetic preparation. It significantly increased to 3.05 ± 0.44 mL ·100 g-1 after the head-down tilt and was around 3.1 mL ·100 g-1 until 120 minutes after the head-down tilt. However, just before the return to the horizontal position, it decreased to 2.93 ± 0.46 mL ·100 g-1 and then decreased more after the return to the horizontal position. Changes in rSO2 over time were within only 3%, and no significant differences from the control value were observed. Conclusions: The increase in CBV was <10% despite the steep head-down tilt and pneumoperitoneum, and it was compensated for at around the end of surgery. Clinically significant changes in rSO2 were not observed during the surgery.

Effects of altering plantar flexion resistance of an ankle-foot orthosis on muscle force and kinematics during gait training.

Ankle-foot orthosis (AFO) can improve gait in stroke patients. Addition of plantar flexion resistance (PFR) can improve the first foot rocker function. However, the effect of changing the PFR on the ankle muscle force during gait training is unclear. This study aimed to determine the effect of changing the PFR of an AFO on spatiotemporal parameters (speed, bilateral step length, and cadence), peak angle of ankle plantar flexion and knee flexion, and muscle force (tibialis anterior [TA], medial head of the gastrocnemius [MGAS], and soleus) during early stance using a musculoskeletal model. Ten healthy adult men walked under five conditions: a no-AFO condition and PFR conditions 1-4. Spatiotemporal parameters and peak joint angles during the early stance phase were measured from experimental data, with muscle force estimated from simulations of a musculoskeletal model. Increasing the PFR of the AFO decreased TA muscle force and increased MGAS muscle force but had no influence on spatiotemporal parameters and joint angles. Adjustment of the PFR modifies the muscle force around the ankle, which can maximize the effect of AFO during gait training.

Estimation of compressive tibiofemoral force using over resistance of ankle-foot orthosis on gait.

The purpose of this study was to investigate the effect of changing the plantar flexion resistance (PFR) of an ankle-foot orthosis (AFO) on the compressive tibiofemoral force, knee muscle forces, and knee joint angle. We measured and estimated knee flexion angle, knee muscle force, and the compressive tibiofemoral force in healthy adult males. The results showed that the first peak compressive tibiofemoral force, peak knee flexion angle, and peak quadriceps muscle force increased in the strong PFR condition compared with the no-AFO condition. These results suggest that over-PFR caused various knee troubles.

Estimation of knee joint reaction force based on the plantar flexion resistance of an ankle-foot orthosis during gait.

[Purpose] The purpose of this study was to investigate the effect of changing the plantar flexion resistance of an ankle-foot orthosis on knee joint reaction and knee muscle forces. Furthermore, the influence of an ankle-foot orthosis with an over-plantar flexion resistance function on knee joint reaction force was verified. [Participants and Methods] Ten healthy adult males walked under the following three conditions: (1) no ankle-foot orthosis, and with ankle-foot orthoses with (2) a strong and (3) a weak plantar flexion resistance (ankle-foot orthosis conditions). The knee flexion angle, quadricep muscle force, hamstring muscle force, and knee joint reaction force during the stance phase were measured using a motion analysis system, musculoskeletal model, and ankle-foot orthosis model. [Results] The peak knee joint reaction force, knee flexion angle, and quadricep muscle force in the early stance phase significantly increased in the strong plantar flexion resistance condition in comparison with the "no ankle-foot orthosis" condition. [Conclusion] Increased knee joint reaction force with over-plantar flexion resistance suggests that over-plantar flexion resistance causes various knee problems such as knee pain and knee osteoarthritis.

Changes of Cerebral Oxygenation in Sequential Glenn and Fontan Procedures in the Same Children.

Recently, it is common to perform the Fontan procedure after the Glenn procedure as surgical repair for the univentricular heart. How the brain oxygen saturation (rSO2) values change with the cardiac restoration and the process of growth during these procedures in individual children remains unknown. In this study, we retrospectively studied rSO2 data as well as the perioperative clinical records of 30 children who underwent both Glenn and Fontan procedures by the same surgeon in the same institute. The rSO2 was measured at the beginning and end of each procedure with an INVOS 5100C. Cerebral perfusion pressure was calculated by subtracting central venous pressure from mean arterial pressure. Arterial oxygen saturation (SaO2) and the hemoglobin concentration were obtained as candidates affecting rSO2 changes at the start and the end of both procedures. The rSO2 increased during the Glenn procedure, but this increase was slight and insignificant. On the other hand, the rSO2 significantly increased during the Fontan procedure. Significant increases in SaO2 were observed only between the beginning and end of the Fontan procedure. Correlation coefficients determined by linear regression analysis were more than 0.5 between rSO2 and SaO2 in both procedures. Multiple linear regression analysis showed that SaO2 was the key determinant of the rSO2. The rSO2 increases step by step from the Glenn to the Fontan procedure in the same patient. Within each procedure, SaO2 is the key determinant of the rSO2. The significance of rSO2 monitoring in these procedures should be further evaluated.

Bioaccumulation of nitroarenes in bivalves at Osaka Bay, Japan.

This paper reports for the first time the detection and occurrence of nitroarenes (NPAHs) in marine organisms. Mussels and oysters collected from Osaka Bay, Japan, had total NPAHs concentrations that ranged from 2380 to 24,688 pg/g dry and 2672 to 25,961 pg/g dry, respectively. Relatively higher concentrations were detected in sampling sites located near the central district and suburbs of Osaka City implying that the most probable sources of NPAHs in the two bivalves are exhaust gases and smokes emitted by automobiles and industrial plants. Bivalves had relatively higher residues of 1-nitronaphthalene, 2-nitronaphthalene, 3-nitrophenanthrene, and 9-nitrophenanthrenes. Residues of 2-nitrofluorene, 1-nitropyrene, 4-nitropyrenes, and 6-nitrochrysene were much lower compared to nitronaphthalenes and nitrophenanthrenes. Inter-species differences was only observed for 2-nitronaphthalene with oysters exhibiting significantly higher residues than mussels.