[Assessment of biomechanical properties of paraspinal muscles in adolescent idiopathic scoliosis].

Objective: To assess the bio-mechanical properties of paraspinal muscles in adolescent idiopathic scoliosis (AIS). Methods: The MyotonPro® device and shear wave elasticity imaging(SWEI) technique were applied to detect the paraspinal muscle tone (F), stiffness (S), relaxation time (R), Deborah number (C) and elasticity (D) of paravertebral muscles on the concave side and convex side of scoliosis curvature at several points: apex of the curve (a), upper (b) and lower (c) limits of the curve in 23 cases of AIS treated from October to December 2017 in Beijing Chaoyang Hospital.Cobb angle of the main curve was measured on the standing anteroposterior whole spine radiograph.Pearson correlation analysis was applied to detect the relation between the bio-mechanical properties and Cobb angle of the main curve. Results: A total of 23 AIS patients [3 males and 20 females, mean age was (15±4) years] were assessed in this study.The mean Cobb angle was (66±33) degrees.The MyotonPro® data showed that the muscle tone on the concave side were all significantly greater than those on the convex side [a: (18.9±2.2) Hz vs (17.4±1.6) Hz, t=4.435, P<0.05; b: (18.2±2.0) Hz vs (16.7±1.7) Hz, t=4.183, P<0.05; c: (18.0±2.3) Hz vs (16.8±1.7) Hz, t=4.520, P<0.05]. The muscle stiffness on the concave side were all significantly greater than those on the convex side at the three points (t=1.974, 2.048, 1.749, all P<0.05). The relaxation time were all longer on the convex side (t=-3.422, -2.713, -2.380, all P<0.05). The Deborah number were greater on the convex side at a and b points (t=-2.939, -2.466, both P<0.05). No significant difference in elasticity was found between the muscles of the two sides.The SWEI results also indicated that the elasticity of the paraspinal muscles of the two sides were similar.The Pearson correlation analysis showed that stiffness on the concave side was moderate positively correlated with Cobb angle of the main curve (r=0.582, P<0.05). Deborah number on the two sides and relaxation time on the concave were moderate negatively correlated with Cobb angle of the main curve (r=-0.632, -0.432, -0.611, all P<0.05). Conclusions: The bio-mechanical properties of paraspinal muscles in AIS are different significantly between the concave and convex side and affected by the severity of scoliosis.

The psychophysiological assessment method for pilot's professional reliability.

BACKGROUND: Previous research has shown that a pilot's professional reliability depends on two relative factors: the pilot's functional state and the demands of task workload. The Psychophysiological Reserve Capacity (PRC) is defined as a pilot's ability to accomplish additive tasks without reducing the performance of the primary task (flight task). HYPOTHESIS: We hypothesized that the PRC was a mirror of the pilot's functional state. The purpose of this study was to probe the psychophysiological method for evaluating a pilot's professional reliability on a simulator. METHODS: The PRC Comprehensive Evaluating System (PRCCES) which was used in the experiment included four subsystems: a) quantitative evaluation system for pilot's performance on simulator; b) secondary task display and quantitative estimating system; c) multiphysiological data monitoring and statistical system; and d) comprehensive evaluation system for pilot PRC. Two studies were performed. In study one, 63 healthy and 13 hospitalized pilots participated. Each pilot performed a double 180 degrees circuit flight program with and without secondary task (three digit operation). The operator performance, score of secondary task and cost of physiological effort were measured and compared by PRCCES in the two conditions. Then, each pilot's flight skill in training was subjectively scored by instructor pilot ratings. In study two, 7 healthy pilots volunteered to take part in the experiment on the effects of sleep deprivation on pilot's PRC. Each participant had PRC tested pre- and post-8 h sleep deprivation. RESULTS: The results show that the PRC values of a healthy pilot was positively correlated with abilities of flexibility, operating and correcting deviation, attention distribution, and accuracy of instrument flight in the air (r = 0.27-0.40, p < 0.05), and negatively correlated with emotional anxiety in flight (r = -0.40, p < 0.05). The values of PRC in healthy pilots (0.61 +/- 0.17) were significantly higher than that of hospitalized pilots (0.43 +/- 0.15) (p < 0.05). The PRC value after 8 h sleep loss (0.50 +/- 0.17) was significantly lower than those before sleep loss (0.70 +/- 0.15) (p < 0.05). CONCLUSION: We conclude that a pilot's PRC, which was closely related to flight ability and functional state, could partly represent the pilot's professional reliability. It is worthwhile to further research using a pilot's PRC as a predictor of mental workload in aircraft design.