Assessment of postural sway with a pendant-mounted wearable sensor

BackgroundBody-worn inertial measurement unit (IMU) sensors have been widely used in postural stability and balance studies because of their low cost and convenience. In most of these studies, a single IMU sensor is attached to a waist belt near the body’s center of mass. Some populations such as pregnant women, however, may find a waist belt challenging in terms of fit and comfort. For this reason it may be useful to identify an alternative location for placement of an IMU and a more comfortable means for attaching the sensor to the body.Research questionDoes placing an IMU sensor in a pendant worn around the neck permit discrimination between conditions with varying postural stability?MethodsTwenty-six healthy participants performed three standing tasks (double-leg, tandem, and single-leg standing) under eyes-open and eyes-closed vision conditions to preliminarily assess the ability of the pendant sensor to discriminate between balance conditions. Discrimination based upon data from a belt-mounted IMU was assessed in the same trials. Differences in standard deviation of acceleration components, sway area, and jerkiness due to trial condition and sensor were evaluated using analysis of variance followed by post hoc comparisons. These data were also incorporated into receiver-operator characteristic (ROC) curve analysis to assess the effectiveness of each sensor at discriminating between conditions.ResultsStability was found to vary across conditions, but there was no interaction between stability and sensor location (all p ≥ 0.323). ROC curve analysis showed that sensors in both locations were good discriminators between conditions.SignificancePlacing an IMU in a pendant may be feasible for studying and monitoring postural instability. This approach may be especially valuable when considering populations for which wearing a belt is uncomfortable.     

Multi-segment spine kinematics: Relationship with dance training and low back pain

BackgroundSpine posture, range of motion (ROM) and movement asymmetry can contribute to low back pain (LBP). These variables may have greater impact in populations required to perform repetitive spine movements, such as dancers; however, there is limited evidence to support this.Research questionWhat is the influence of dance and LBP on spinal kinematics?MethodsIn this cross-sectional study, multi-segment spinal kinematics were examined in 60 female participants, including dancers (n = 21) and non-dancers (n = 39) with LBP (n = 33) and without LBP (n = 27). A nine-camera motion analysis system sampling at 100 Hz was used to assess standing posture, as well as ROM and movement asymmetry for side bend and trunk rotation tasks. A two-way ANOVA was performed for each of the outcome variables to detect any differences between dancers and non-dancers, or individuals with and without LBP.ResultsCompared to non-dancers, dancers displayed a flatter upper lumbar angle when standing (p < 0.01, ηp² = 0.15), and achieved greater frontal plane ROM for the upper lumbar (p = 0.04, ηp² = 0.08) and lower thoracic (p = 0.02, ηp² = 0.09) segments. There were no differences between dancers and non-dancers for transverse plane ROM (p > 0.05) or movement asymmetry (p > 0.05). There was no main effect for LBP symptoms on any kinematic measures, and no interaction effect for dance group and LBP on spinal kinematics (p > 0.05).SignificanceFemale dancers displayed a flatter spine posture and increased spine ROM compared to non-dancers for a select number of spine segments and movement tasks. However, the overall number of differences was small, and no relationship was observed between LBP and spinal kinematics. This suggests that these simple, static posture, ROM, and asymmetry measures often used in clinical practice can provide only limited generalisable information about the impact of dance or LBP on spinal kinematics.     

Stereophotogrammetric measurement of the nasolabial fold in repose: a study of age and posture-related changes

The nasolabial fold is a significant facial landmark. Its size, shape, and symmetry are important in facial reanimation surgery, while effacement is an important goal in rejuvenation surgery. However, quantitative data for the nasolabial fold volume (NLFV) and depth is still unavailable. We present a new method of measurement using 3D color speckle stereophotogrammetry and its application in the assessment of NLFV. The VECTRA-3D system was validated to determine its minimum resolution and accuracy. Normal volunteers aged 13–84 years (n = 87) were imaged in repose. Mother–daughter pairs (n = 15, aged 13–61) were imaged in the upright and supine positions. All data were processed using custom software and analyzed by linear regression and nonparametric tests as appropriate. NLFV varied from 0.0026 to 0.2306 ml. There was significant correlation between NLFV and age (r = 0.7269, p < 0.0001). Men had significantly higher NLFV than women across all ages. There was no significant difference between the left and right NLFV. NLFV altered significantly from upright to supine in all subjects (p = 0.0012). However, the mothers increased their NLFV by 32% from supine to upright postures, which was a greater change than observed in their daughters. We have demonstrated a rapid, objective, and non-invasive assessment tool for facial reanimation and rejuvenation surgery. We have quantified the effects of age and posture on NLFV, and the efficacy and longevity of rejuvenation procedures are currently under investigation.     

Conditioned and unconditioned forelimb reflex systems in the cat: involvement of the intermediate cerebellum

 Temporary inactivation of the cerebellar interposed nuclei was used to assess the role of the intermediate cerebellum in the performance of forelimb cutaneo-muscular reflexes in the cat. The following types of reflexive responses were evaluated: the classically conditioned and unconditioned forelimb withdrawal responses and the forelimb tactile placing, hopping and magnet responses. The experiments tested the hypothesis that the intermediate cerebellum is involved in the performance of all the above forelimb reflexes. The forelimb withdrawal reflex was classically conditioned in a newly developed paradigm in which animals were first operantly conditioned to stand on four elevated platforms. Trained animals were microinjected with a γ-aminobutyric acid (GABA) agonist, muscimol, in the interposed nuclei, and the effects of inactivation of the intermediate cerebellar output on the forelimb reflexes were examined. The main findings of these experiments are that unilateral muscimol inactivation of the interposed nuclei in the cat abolished the expression of the classically conditioned limb flexion reflex, suppressed the performance of the unconditioned withdrawal reflex and, in parallel, downregulated the tactile placing, hopping and magnet postural responses in the ipsilateral forelimb. These observations are inconsistent with concepts indicating exclusive involvement of the intermediate cerebellum in the classically conditioned reflexes elicited by aversive stimuli. On the contrary, they support the hypothesis of a more global involvement of this structure in learned and unlearned defensive flexion reflexes and in automatic postural response systems. Received: 29 July 1996 / Accepted: 26 September 1996     

New posture equilibrometer for the diagnosis of vestibular disease

Summary The vestibulospinal level of vestibular function is commonly neglected in the evaluation of vertiginous patients. We have now developed a new posture equilibrometer. A transducer is placed on the head of the subject being tested. With this meter we can record body swaying, X (left-right) and Y (fore-aft) components of angular displacement, angular velocity, and angular acceleration. A detailed analysis of the data can be made by having patients keep their eyes either open or closed during the Romberg test. The head is turned left or right in this test, while the eyes are opened and closed in the Mann test. The posture equilibrometer has enabled us to evaluate more precisely vestibulospinal function and sensory interactions. Offprint request to: N. C. Zhong     

Study of the course of the incidence angle during growth

Standing posture is made possible by hip extension and lumbar lordosis. Lumbar lordosis is correlated with pelvic parameters, such as the declivity angle of the upper surface of the sacrum and the incidence angle, which determine the sagittal morphotype. Incidence angle, which is different for each individual, is known to be very important for upright posture, but its course during life has not yet been established. Incidence angle was measured on radiographs of 30 fetuses, 30 children and 30 adults, and results were analysed using the correlation coefficientr and Student's t test. A statistically significant correlation between age and incidence angle was observed. Incidence angle considerably increases during the first months, continues to increase during early years, and stabilizes around the age of 10 years. Incidence is a mark of bipedism, and its role in sagittal balance is essential.     

体位改变对胸科手术病人双腔支气管导管位置的影响

目的 探讨体位改变对双腔支气管导管位置的影响。方法 择期开胸手术病人100例，ASAⅠ或Ⅱ级，随机分为两组（n=50）：左双腔支气管导管组（L-DLT组）及右双腔支气管导管组（R—DLT组）。全麻诱导后分别插入左、右双腔支气管导管，用纤维支气管镜（FOB）确定导管位置。病人体位由平卧位改为侧卧位后，用听诊法和FOB再次检查、确定导管位置。记录结果和DLT深度。结果 与平卧位相比，L-DLT组的DLT深度均变浅（P〈0．05）；R-DLT组的置入深度变化男性差异无统计学意义（P〉0．05），女性变浅（P〈0．05）。体位改变后，听诊法判断DLT位置不满意的13例，其中L-DLT组为5例（10％），R-DLT组为8例（16％）。FOB检查导管位移32例，其中L-DLT组管端位移12例（24％），包括严重位移3例（6％）；R—DLT组管端位移20例（40％），包括严重位移7例（14％）。位移率和严重位移率R-DLT组均高于L-DLT组（P〈0．05）。结论 体位改变对DLT位置有较大影响。FOB检查的准确性明显高于听诊法。     

机械通气患者体位改变插入胃管效果与分析

目的提高有创机械通气患者插入胃管的成功率,减少因反复插管所致的并发症,减轻患者痛苦,提高护士的工作效率。方法把有创机械通气的60例患者,随机分为观察组30例和对照组30例,观察组采取改变常规的“去枕头后仰位”为“抬高床头70°~80°角,头正位”插入胃管,对照组采取常规的去枕头后仰卧位的体位方法插入胃管。结果对照组一次插管成功率为6.66%,观察组一次插管成功率为90%,经统计学分析,差异有显著意义(P<0.01)。结论有创机械通气患者改变常规的“去枕头后仰位”为“抬高床头70°~80°角,头正位”后一次插入胃管成功率明显提高。     

隐性脐带脱垂30例临床观察及护理分析

目的探讨加强预防隐性脐带脱垂的治疗及护理措施.方法2001年1月～2004年6月在我院分娩共2150例.初产妇1950例,经产妇200例,其中隐性脐带脱垂30例,30例中,胎先露与骨盆入口衔接不良及第一产程或第二产程出现异常等情况,给予相应的护理.结果30例中,第一产程活跃期或第二产程出现胎头下降阻滞,均在进行人工破膜,阴道内诊,徒手旋转胎头处理后2～5min突然出现胎心减速100次/分以下,经吸氧,滴注5%碳酸氢钠处理后,16例胎心音好转,顺产,14例出现明显胎儿窘迫,其中12例行急诊剖宫产,2例钳产.新生儿出生时Apar评分8～10分2例,5～7分8例,4分以下2例,手术及分娩时证实隐性脐带脱垂.结论隐性脐带脱垂易发生脐带绕颈,相对头盆不称、巨大胎儿、羊水过多者,经徒手转胎头纠正异常胎方位,应立即给予吸氧,胎心监护仪监测胎心变化的护理,宫口未开全即将产妇的体位以头低臀高位约15～30°,或采取侧卧位,减轻脐带受压,同时静脉滴注葡萄糖、维生素C,以提高缺氧的耐受性和降低毛细血管通透性.预防、治疗隐性脱垂,因采取了有效的护理措施,加强对隐性脐带脱垂的认识,并及时诊断处理,母儿预后良好.     

A comparison of surgeons' posture during laparoscopic and open surgical procedures

Background: There is increasing recognition of surgeons' physical fatigue in the new ergonomic environment of laparoscopic surgery. The purpose of this study was to determine what the differences are in the movement of the surgeon's axial skeleton between laparoscopic and open operations. Methods: Surgeons' body positions were recorded on videotape during four laparoscopic (LAP) and six open (OP) operations. The percent of time the head and back were in a normal, bent, or twisted position as well as the number of changes in head and back position were tabulated using a computer program. A separate laboratory study was performed on four surgeons ``walking' a 0.5-inch polyethylene tubing forward and backward using laparoscopic and open techniques. The movements of the surgeons' head, trunk, and pelvis were measured using a three-camera kinematic system (Kin). The center of pressure was recorded using a floor-mounted forceplate (Fp). Results: In the operating room surgeons' head and back positions were more often straight in laparoscopic procedures and more often bent in open operations. The number of changes in back position per minute were significantly decreased when the laparoscopic-only part of surgery was analyzed. In the laboratory the subjects' head position was significantly (p= 0.02) more upright and the anteroposterior (AP) and rotational range of motion of the head was significantly reduced during laparoscopy. Subjects' CP was more anterior and there was a significant reduction in the AP range of motion of the CP during laparoscopy. Conclusions: Our study suggests that surgeons exhibit decreased mobility of the head and back and less anteroposterior weight shifting during laparoscopic manipulations despite a more upright posture. This more restricted posture during laparoscopic surgery may induce fatigue by limiting the natural changes in body posture that occur during open surgery. Received: 3 March 1996/Accepted: 2 July 1996