Preoperative Motor Function Associated with Short-Term Gain of Health-Related Quality of Life after Surgery for Lumbar Degenerative Disease: A Pilot Prospective Cohort Study in Japan.

This study aimed to estimate the relationship between preoperative motor function and short-term recovery of health-related quality of life after lumbar surgery in patients with lumbar degenerative disease. This prospective cohort study involved 50 patients with lumbar degenerative disease at a general hospital in Japan. The primary outcome was the achievement of minimal clinically important difference (MCID) for EuroQOL 5 dimensions (EQ-5D) at discharge. Preoperative demographic, medication, surgical, and physical function data were collected. Logistic regression analysis was performed using the achievement of MCID for EQ-5D as the dependent variable and preoperative characteristics, including the Five Times Sit to Stand test (FTSTS), Oswestry Disability Index (ODI), and Self-rating Depression Scale (SDS), as the independent variables. The logistic regression analysis showed that Model 1 had a moderate predictive accuracy (Nagelkerke R2: 0.20; Hosmer-Lemeshow test: p = 0.19; predictive accuracy: 70.0%). Among the independent variables in the logistic regression model, the FTSTS was the only independent variable related to the achievement of MCID for EQ-5D at discharge (odds ratio: 0.03; 95% CI: 1.79 × 10-3, 0.18). Our results highlighted the importance of baseline motor function in the postoperative recovery of health-related quality of life in individuals with lumbar degenerative disease.

Effects of visual feedback of thoracoabdominal motion on oxygen consumption during hyperventilation - Pilot study.

INTRODUCTION: Respiratory muscle oxygen consumption increases with the work of breathing. We hypothesized that reducing excessive respiratory muscle activity during exercise may improve exercise tolerance. METHOD: We developed a device to provide real-time visual feedback of thoracoabdominal movement and used it to examine the influence of visual feedback of thoracoabdominal movement during diaphragmatic breathing on oxygen consumption in eight healthy men. While sitting on a wheelchair with the backrest reclined at 60°, oxygen consumption per body weight (VO2/BW), minute ventilation (VE), tidal volume (VT), and breathing frequency (fR) were measured, breath-by-breath, using an expired-gas analyzer. The breathing pattern was analyzed by inductance plethysmography, with transducer bands over the chest and abdomen recording thoracoabdominal movements. RESULTS: There was no significant difference in RatioTH-ABD and the ventilatory parameters between diaphragmatic breathing and diaphragmatic breathing with visual feedback. The average VO2/BW during diaphragmatic breathing with visual feedback was 0.6 ml/kg lower than that during diaphragmatic breathing without visual feedback (p<0.05). CONCLUSION: When visual feedback was used during diaphragmatic breathing, the RatioTH-ABD remained essentially unchanged, but VO2/BW decreased significantly. This suggests that visual feedback of thoracoabdominal movement during diaphragmatic breathing may reduce respiratory muscle oxygen consumption.

Detection of Movement Events of Long-Track Speed Skating Using Wearable Inertial Sensors.

Inertial measurement units (IMUs) have been used increasingly to characterize long-track speed skating. We aimed to estimate the accuracy of IMUs for use in phase identification of long-track speed skating. Twelve healthy competitive athletes on a university long-track speed skating team participated in this study. Foot pressure, acceleration and knee joint angle were recorded during a 1000-m speed skating trial using the foot pressure system and IMUs. The foot contact and foot-off timing were identified using three methods (kinetic, acceleration and integrated detection) and the stance time was also calculated. Kinetic detection was used as the gold standard measure. Repeated analysis of variance, intra-class coefficients (ICCs) and Bland-Altman plots were used to estimate the extent of agreement between the detection methods. The stance time computed using the acceleration and integrated detection methods did not differ by more than 3.6% from the gold standard measure. The ICCs ranged between 0.657 and 0.927 for the acceleration detection method and 0.700 and 0.948 for the integrated detection method. The limits of agreement were between 90.1% and 96.1% for the average stance time. Phase identification using acceleration and integrated detection methods is valid for evaluating the kinematic characteristics during long-track speed skating.

Investigation of inspiratory intercostal muscle activity in patients with spinal cord injury: a pilot study using electromyography, ultrasonography, and respiratory inductance plethysmography.

[Purpose] The respiratory function in patients with cervical spinal cord injury is influenced by inspiratory intercostal muscle function. However, inspiratory intercostal muscle activity has not been conclusively evaluated. We evaluated the inspiratory intercostal muscle activity in patients with cervical spinal cord injury by using inspiratory intercostal electromyography, respiratory inductance plethysmography, and ultrasonography. [Participants and Methods] Three patients with cervical spinal cord injury were assessed. The change in mean amplitude (rest vs. maximum inspiration) was calculated by using intercostal muscle electromyography. Changes in intercostal muscle thickness (resting expiration and maximum inspiration) were also evaluated on ultrasonography. The waveform was converted to spirometry ventilation with respiratory inductance plethysmography, and the waveform at the xiphoid was considered to determine the rib cage volume. Each index was compared with the inspiratory capacities in each case. [Results] Intercostal muscle electromyography failed to measure the notable myoelectric potential in all the patients. The rib cage volume was higher at higher inspiratory capacities. The changes in muscle thickness were not significantly different between the patients. [Conclusion] The rib cage volume (measured with inductance plethysmography) was greater in the patients with cervical spinal cord injury when inspiratory intercostal muscle activity was high. Respiratory inductance plethysmography can capture inspiratory intercostal muscle function in patients with cervical spinal cord injury.

Enhanced image sensing with avalanche multiplication in hybrid structure of crystalline selenium photoconversion layer and CMOSFETs.

The recent improvements of complementary metal-oxide-semiconductor (CMOS) image sensors are playing an essential role in emerging high-definition video cameras, which provide viewers with a stronger sensation of reality. However, the devices suffer from decreasing sensitivity due to the shrinkage of pixels. We herein address this problem by introducing a hybrid structure comprising crystalline-selenium (c-Se)-based photoconversion layers and 8 K resolution (7472 × 4320 pixels) CMOS field-effect transistors (FETs) to amplify signals using the avalanche multiplication of photogenerated carriers. Using low-defect-level NiO as an electric field buffer and an electron blocking layer, we confirmed signal amplification by a factor of approximately 1.4 while the dark current remained low at 2.6 nA/cm2 at a reverse bias voltage of 22.6 V. Furthermore, we successfully obtained a brighter image based on the amplified signals without any notable noise degradation.

Oxygen cost of thoracic and diaphragmatic breathing during hyperventilation in healthy males.

[Purpose] It is unclear whether diaphragmatic breathing (DB) results in lower respiratory muscle oxygen consumption during dynamic exercise. The purpose of this study was to compare oxygen consumption in the respiratory muscles (VO2rm) with thoracic breathing (TB) and with DB, in healthy males during hyperventilation. [Subjects and Methods] Ten healthy men participated in this study. The subjects sat on a chair with the backrest reclined at an angle of 60 degrees. Respiratory parameters were measured breath by breath, using an expired gas analyzer. Oxygen consumption was measured for three minutes during quiet breathing. Measurements during TB and DB were performed for one minute each, after connecting a rebreather loading device. The breathing pattern was analyzed by inductance plethysmography, using transducer bands placed over the chest and abdomen that recorded thoracoabdominal movements. [Results] Both ΔVO2/body weight and VO2rm decreased significantly with DB when compared to that with TB, during hyperventilation. [Conclusion] DB results in less respiratory muscle oxygen consumption, even during dynamic exercise.

Functional electrical stimulation to the abdominal wall muscles synchronized with the expiratory flow does not induce muscle fatigue.

[Purpose] Continuous electrical stimulation of abdominal wall muscles is known to induce mild muscle fatigue. However, it is not clear whether this is also true for functional electrical stimulation delivered only during the expiratory phase of breathing. This study aimed to examine whether or not intermittent electrical stimulation delivered to abdominal wall muscles induces muscle fatigue. [Subjects and Methods] The subjects were nine healthy adults. Abdominal electrical stimulation was applied for 1.5 seconds from the start of expiration and then turned off during inspiration. The electrodes were attached to both sides of the abdomen at the lower margin of the 12th rib. Abdominal electrical stimulation was delivered for 15 minutes with the subject in a seated position. Expiratory flow was measured during stimulus. Trunk flexor torque and electromyography activity were measured to evaluate abdominal muscle fatigue. [Results] The mean stimulation on/off ratio was 1:2.3. The declining rate of abdominal muscle torque was 61.1 ± 19.1% before stimulus and 56.5 ± 20.9% after stimulus, not significantly different. The declining rate of mean power frequency was 47.8 ± 11.7% before stimulus and 47.9 ± 10.2% after stimulus, not significantly different. [Conclusion] It was found that intermittent electrical stimulation to abdominal muscles synchronized with the expiratory would not induce muscle fatigue.

Compression of the lungs by the heart in supine, side-lying, semi-prone positions.

[Purpose] Clarification of the differences in the compression volume of the lungs by the heart (CVLH) between postures may facilitate the selection of optimal postures in respiratory care. Determining CVLH in the supine, semi-prone (Sim's position), and side-lying positions was the aim of this study. [Subjects and Methods] Eight healthy volunteers (six males, two females; mean age, 29.0 ± 9.2 years) were enrolled in the study. Measurements were performed in the supine, right and left semi-prone, and right and left side-lying positions. semi-prone position was inclined 45° ventrally from the side-lying position. A 1.5-T system with a fast advanced spin-echo sequence in the coronal plane was used for magnetic resonance imaging. [Results] CVLH and heart compression ratio were significantly lower in the semi-prone position on both sides than the other positions. The heart was displaced ventrally when semi-prone and a larger area of the heart leaned on the ventral chest wall, localizing compression to part of the ventral region of the dependent lung. [Conclusion] The region of lungs compressed by the heart is reduced in the semi-prone position due to ventral displacement of the heart. These results suggest that maintaining expansion of the dependent lung is easier in the semi-prone position.

Regional lung volume differences between the side-lying and semi-prone positions.

[Purpose] This study aimed to clarify the differences in regional lung volume between the semi-prone (Sim's position) and side-lying position, and the optimal position for increasing lung volume. [Methods] Measurements were performed in both positions on both sides. Sim's position was inclined 45° forward from the side-lying position. A 1.5-T system with a fast advanced spin-echo sequence in the coronal plane was used for magnetic resonance imaging. [Results] The two positions did not significantly differ in total lung capacity and its subdivisions on both sides, except the left lung in the right side-lying position and right Sim's position. In the nondependent lung, the percentage lung volume of the dorsal segment was significantly higher in the right Sim's position than in the right side-lying position. However, no significant difference was observed between the left side-lying and left Sim's position. [Conclusion] The heart was displaced ventrally by gravity in Sim's position and leaned on the ventral parapet. The spaces for the expansion of the ventral and dorsal segments of the lung were decreased and increased in Sim's position, respectively. With a nondependent left lung, the increase in the percentage lung volume of the dorsal segment was greater in Sim's position than in the side-lying position.

Respiratory flow and vital signs associated with the intensity of functional electrical stimulation delivered to human abdominal muscles during quiet breathing.

[Purpose] The purpose of this study was to examine the effects of increasing the intensity of functional electrical stimulation delivered to abdominal muscles during quiet breathing on respiratory flow, vital signs and pain in healthy subjects. [Subjects and Methods] Electrical stimulation was delivered bilaterally using one pair of high-conductivity gel-skin plate electrodes, placed on both sides of the abdomen, to nine healthy males. Subjects were required to breathe normally through a face mask for 2 minutes while in a supine position. The stimulation intensity was incrementally increased by 10 mA until reaching 100 mA. Respiratory parameters, vital signs and pain based on the visual analog scale were measured for each intensity of electrical stimulation. [Results] Transcutaneous oxygen saturation showed a slight upward trend in association with increasing stimulation intensity, but there were no significant changes in pulse or blood pressure. Respiratory flow, tidal volume, and minute ventilation increased significantly as the stimulation intensity rose. [Conclusion] This study revealed that functional electrical stimulation can be safely delivered to human abdominal muscles without causing vital sign abnormalities. It was also found that the appropriate intensity level of electrical stimulation for achieving effects on respiratory flow while also minimizing pain is 60-80 mA.