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BACKGROUND Hyperpolarized 129 Xe magnetic resonance imaging (MRI) provides a non-invasive assessment of regional pulmonary gas exchange function. This technique has demonstrated that chronic obstructive pulmonary disease (COPD) patients exhibit ventilation defects, reduced interstitial barrier tissue uptake, and poor transfer to capillary red blood cells (RBCs). However, the behavior of these measurements following therapeutic intervention is unknown. PURPOSE To characterize changes in 129 Xe gas transfer function following administration of an inhaled long-acting beta-agonist/long-acting muscarinic receptor antagonist (LABA/LAMA) bronchodilator. STUDY TYPE Prospective. POPULATION Seventeen COPD subjects (GOLD II/III classification per Global Initiative for Chronic Obstructive Lung Disease criteria) were imaged before and after 2 weeks of LABA/LAMA therapy. FIELD STRENGTH/SEQUENCES Dedicated ventilation imaging used a multi-slice 2D gradient echo sequence. Three-dimensional images of ventilation, barrier uptake, and RBC transfer used an interleaved, radial, 1-point Dixon sequence. Imaging was acquired at 3 T. ASSESSMENT 129 Xe measurements were quantified before and after LABA/LAMA treatment by ventilation defect + low percent (vendef + low ) and by barrier uptake and RBC transfer relative to a healthy reference population (bar%ref and RBC%ref ). Pulmonary function tests, including diffusing capacity of the lung for carbon monoxide (DLCO ), were also performed before and after treatment. STATISTICAL TESTS Paired t-test, Pearson correlation coefficient (r). RESULTS Baseline vendef + low was 57.8 ± 8.4%, bar%ref was 73.2 ± 19.6%, and RBC%ref was 36.5 ± 13.6%. Following treatment, vendef + low decreased to 52.5 ± 10.6% (P

BACKGROUND Despite the association of masticatory function with head posture and mandible movement, the impact of head posture on masseter muscle electrical activity remains unclear. This study aimed to investigate the electrical activity of the anterior temporal, masseter, superior trapezius, and sternocleidomastoid muscles in temporomandibular disorder (TMD) patients in three different head positions and compare the findings with those for healthy subjects. METHODS The study included 16 TMD patients and 17 healthy subjects. Surface electromyography (sEMG) was used to assess the bilateral anterior temporalis, masseter, superior trapezius, and sternocleidomastoid muscle activities. The maximal voluntary contraction (MVC) and root mean square (RMS) sequence of each muscle were measured in three head positions. Mixed analysis of variance was used to evaluate the effects of head posture on muscle electrical activity in each group. RESULTS The group differences for the bilateral masseter muscles were significant in the relaxation position, neutral head position (NHP), and relaxation position with tooth contact (P

Hyperpolarized (129)Xe MRI has emerged as a novel means to evaluate pulmonary function via 3D mapping of ventilation, interstitial barrier uptake, and RBC transfer. However, the physiological interpretation of these measurements has yet to be firmly established. Here, we propose a model that uses the three components of (129)Xe gas-exchange MRI to estimate accessible alveolar volume (V(A)), membrane conductance, and capillary blood volume contributions to DL(CO). (129)Xe ventilated volume (VV) was related to V(A) by a scaling factor k(V) = 1.47 with 95% confidence interval [1.42, 1.52], relative (129)Xe barrier uptake (normalized by the healthy reference value) was used to estimate the membrane-specific conductance coefficient k(B) = 10.6 [8.6, 13.6] mL/min/mmHg/L, whereas normalized RBC transfer was used to calculate the capillary blood volume-specific conductance coefficient k(R) = 13.6 [11.4, 16.7] mL/min/mmHg/L. In this way, the barrier and RBC transfer per unit volume determined the transfer coefficient K(CO), which was then multiplied by image-estimated V(A) to obtain DL(CO). The model was built on a cohort of 41 healthy subjects and 101 patients with pulmonary disorders. The resulting (129)Xe-derived DL(CO) correlated strongly (R(2) = 0.75, P < 0.001) with the measured values, a finding that was preserved within each individual disease cohort. The ability to use (129)Xe MRI measures of ventilation, barrier uptake, and RBC transfer to estimate each of the underlying constituents of DL(CO) clarifies the interpretation of these images while enabling their use to monitor these aspects of gas exchange independently and regionally. NEW & NOTEWORTHY The diffusing capacity for carbon monoxide (DL(CO)) is perhaps one of the most comprehensive physiological measures used in pulmonary medicine. Here, we spatially resolve and estimate its key components—accessible alveolar volume, membrane, and capillary blood volume conductances—using hyperpolarized (129)Xe MRI of ventilation, interstitial barrier uptake, and red blood cell transfer. This image-derived DL(CO) correlates strongly with measured values in 142 subjects with a broad range of pulmonary disorders.

Background Sleep bruxism (SB) patients show a higher incidence of leg movements than normal subjects. Study objectives The study aimed to characterize SB episodes and their relationships with limb movements (LMs). Materials and methods Polysomnographic (PSG) recordings were performed on eight SB patients. The intervals between the onsets of adjacent SB episodes and LMs were determined and linear correlation analyses were used to estimate the relationship between the SB index and SB episodes in clusters. The Pearson χ2 and partitions of χ2 tests were used to analyze the differences in incidence of SB episodes and clusters in different sleep stages. Results A majority of SB episodes (85.05%) were found to be accompanied by LMs and among them, 70.52% SB episodes occurred with movements of both upper and lower limbs and most of LMs (70.54%) occurred before the onset of SB episodes. Most of SB episodes especially those accompanied by LMs occurred with microarousals or awakenings. Linear correlation analysis showed a positive correlation between the SB index and SB episodes in clusters (r2 = 0.7027, P = 0.0093). In addition, the percentage of SB episodes in clusters accompanied by LMs was significantly smaller than that of SB episodes not accompanied by LMs (χ2 test, P Conclusions Most SB episodes might not be isolated events, but rather a part of a series of movements second to changes in arousal level.

Lower limb rehabilitation robots have been widely used in medical treatment in recent years. The safety of robot in rehabilitation training should be considered. In this paper, the method to analyze complicated inverse kinematics and forward dynamics of lower limb rehabilitation robot is studied. Because of the mathematical model of lower limb is difficult to establish, the OpenSim software is used to simulate and analyze the human gait data which collected by the NOKOV optical motion capture system. According to the inverse kinematics simulation, the curve of each joint angle changing over time is obtained, and the reaction force acting on the ground is obtained through the forward dynamics simulation.

Patients with chronic ankle instability (CAI) have postural-control deficits during center-of-pressure excursions than do healthy individuals. While an external analysis of center-of-pressure excursions in CAI has been performed, a quantitative analysis of center-of-gravity movements, to detect the balance deficits associated with CAI, has yet to be performed. Therefore, the aim of the study is to quantify the balance deficits in patients with unilateral CAI. Forty-four patients with unilateral CAI (24 men; age, 31.7 ± 5.5 years) and 26 uninjured volunteers (12 men; age, 28.6 ± 5.9 years) underwent Neurocom Balance Manager assessments of dynamic and static balance responses in limits of stability, unilateral stance, and forward lunge tests. In the limits of stability test, there were no significant group differences in the forward direction; however, reaction times were longer in the CAI group than in the control group in the backward (P = .037, effect size [ES] = 0.49) and rightward directions (P = .032, ES = 0.47). Furthermore, the CAI group showed more excursions in the rightward (P = .046, ES = 0.50) and leftward directions (P = .002, ES = 0.80), and less directional control in the leftward direction (P = .036, ES = 0.59). In the unilateral stance test, the center of gravity sway velocity was faster in the CAI group than in the control group, whether eyes were opened or closed (P < .05). There were no significant group differences in forward lunge-test outcomes. Patients with CAI have poor static and dynamic balance performance compared to that in healthy counterparts. Thus, balance retraining should be an essential component of rehabilitation programs for patients with CAI.