Effect Of Postural Changes Research Articles

Effects of sitting, supine, and prone postures on nasal patency in individuals with obstructive sleep apnea syndrome

BackgroundStudies have found that in healthy individuals without nasal disease, changes in posture cause an increase in nasal resistance, especially in the prone posture. Many patients with obstructive sleep apnea syndrome (OSAS) sleep in a prone posture, but no studies have examined the effect of this change in posture on nasal resistance in patients with OSAS. Therefore, we conducted this study to investigate this posture-related physical phenomenon in individuals with OSAS.MethodsWe evaluated the nasal patency of 29 patients diagnosed with OSAS using the visual analog scale (VAS), acoustic rhinometry, and video-endoscopy in the sitting, supine, and prone postures.ResultsIn the OSAS group, both supine and prone postures significantly influenced subjective nasal blockage and led to a notable reduction in the minimal cross-sectional area (mCSA) as determined by acoustic rhinometry, compared to the sitting posture. The prone posture exhibited a more pronounced effect than the supine posture. Endoscopic evaluations further revealed increased hypertrophy of the inferior turbinate in the supine posture for the right nasal passage and the prone posture for the left. However, no significant differences were observed between the prone and supine postures.ConclusionIn OSAS patients, nasal resistance significantly increased in supine and prone postures compared to sitting, with the prone posture showing a greater effect. Clinicians should consider a patient’s habitual sleep posture and the effects of postural changes when assessing OSAS severity and devising treatment plans.Level of Evidence4.

Upright CT-based evaluation of the effects of posture on skull-base reconstruction after endoscopic endonasal surgery

Cerebrospinal fluid (CSF) leakage is a common complication associated with endoscopic endonasal skull-base surgery (EESBS). Postoperative mobilization-associated postural changes are considered to cause CSF leakage. However, no study has demonstrated a robust relationship between postural changes and CSF leakage. We used upright computed tomography (CT) to clarify the effects of postural changes on the reconstructed skull base (RSB) after EESBS. Thirty patients who underwent EESBS at our institution were prospectively included, and their upright and supine CTs were compared to measure morphological changes in the RSB. Patient clinical data were also collected from medical charts and surgical videos, and their relationships with morphological changes were assessed. In upright CTs, the RSB shifted intracranially by 0.94 (0.0–2.9) mm on average. This shift was larger in cases with lesions extending to the sphenoid sinus, dural defects, intraoperative pulsation of the RSB, and large bone windows. The direction of the change was opposite to intuitive movement driven by gravity because of reduced intracranial pressure in the sitting position. Thus, these shifts can be directly associated with postoperative CSF leakage caused by reconstruction material displacement. Skull-base reconstruction and postoperative postural management accounting for these morphological changes may be necessary for preventing CSF leakage.

No influence of steady-state postural changes on cerebrovascular compliance in humans.

The aim of this study was to determine the effect of posture changes on vascular compliance in intracranial (brain) versus extracranial vascular beds (forearm). Eighteen young adults (nine females) performed a supine-to-seated-to-standing protocol involving 5 min of rest in each position. Continuous blood pressure, middle cerebral artery (MCA) blood velocity, and brachial artery blood velocity were recorded at each posture. Three to five consecutive steady-state cardiac cycles at each posture were analyzed by a four-element lumped parameter modified Windkessel model to calculate vascular compliance. Mean arterial pressure (MAP) increased from supine to seated (76(9) vs. 81(12) mmHg; P=0.006) and from supine to standing (76(9) vs. 82(13) mmHg; P=0.034). Mean blood flow was greater in the MCA relative to the forearm (forearm: 40(5) mL·min-1, MCA: 224(17) mL·min-1; main effect P<0.001). Conversely, vascular resistance (forearm: 3.25(0.50) mmHg-1·mL·min-1, brain: 0.36(0.04) mmHg-1·mL·min-1; main effect P<0.001) and compliance (forearm: 0.010(0.001) mL·min-1·mmHg-1, brain: 0.005(0.001) mL·min-1·mmHg-1; main effect P=0.001) were greater in the forearm compared to the brain. Significant main effects of posture were observed with decreasing values in upright positions for mean blood flow (P=0.001) in both vascular beds, but not for resistance (P=0.163) or compliance (P=0.385). There were no significant interaction effects between vascular bed and posture for mean flow (P=0.057), resistance (P=0.258), or compliance (P=0.329). This study provides evidence that under steady-state conditions, posture does not affect cerebrovascular compliance.

앉은 자세에서의 목 안정화 운동이 목통증 환자의 심부 근두께 변화량, 경부 통증, 기능장애지수에 미치는 영향

Objective: The purpose was to measure changes in neck pain, NDI, and deep neck muscle thickness during neck stabilization exercises in a sitting position, and to confirm the effects of postural changes.&#x0D; Method: Participants were divided into a lying posture exercise group (10 participants) and a sitting posture exercise group (10 participants) to perform neck stabilization exercises. Both groups will receive treatment for 20 minutes three times a week for four weeks, and participants will complete a pretest and reassess previously assessed items after a total of four weeks of intervention.&#x0D; Results: Within both groups, the change in deep neck muscle thickness increased significantly in the before-after comparison, but there was no significant difference in the between-group comparison. Within both groups, neck pain was significantly reduced when comparing before and after, but there was no significant difference when comparing between both groups. Within both groups, the NDI was significantly reduced when comparing before and after, and there was also a significant difference when comparing between both groups.&#x0D; Conclusion: Neck stabilization exercises in a sitting position are an effective movement mediation method.

Changes in Respiratory Mechanics With Trunk Inclination Differs Between Patients With ARDS With and Without Obesity

Studies investigating the effect of trunk inclination on respiratory mechanics in mechanically ventilated patients with ARDS have reported postural differences in partition respiratory mechanics. Compared with more upright positions, the supine-flat position provided lower lung and chest wall elastance, allowing reduced driving pressures and end-inspiratory transpulmonary pressure. However, the effect of trunk inclination on respiratory mechanics in patients with obesity and ARDS is uncertain. Does the effect of change in posture on partition respiratory mechanics differ between patients with ARDS with and without obesity? In this single-center study, patients with ARDS with and without obesity were randomized into two 15-minute steps in which trunk inclination was changed from semi-recumbent (40° head up) to supine-flat (0°), or vice versa. At the end of each step partition respiratory mechanics, airway opening pressure and arterial blood gases were measured. Paired t test was used to examine respiratory mechanics and blood gas variables in each group. Forty consecutive patients were enrolled. Twenty were obese (BMI, 38.4 [34.5-42.3]), and 20 were non-obese (BMI, 26.6 [25.2-28.5]). In the patients with obesity, lung and chest wall elastance, driving pressure, inspiratory transpulmonary pressure, Paco2, and ventilatory ratio were lower supine than semi-recumbent (P< .001). Airways resistance was greater supine (P= .006). In the patients without obesity, only chest wall elastance was lower in supine vssemi-recumbent (P< .001). In mechanically ventilated patients with ARDS and obesity, supine posture provided lower lung and chest wall elastance, and better CO2 clearance, than the semi-recumbent posture. This study was registered with Australian New Zealand Clinical Trials Registry (ACTRN12623000794606).

Imaging study of the effect of postural changes on the retroperitoneal oblique corridor in degenerative lumbar scoliosis.

To investigate the effect of postural changes on access for the OLIF of L2 to L5 in patients with degenerative lumbar scoliosis. Twenty-one individuals with degenerative lumbar scoliosis were chosen at random, 11 with left-sided convexity and 10 with left-sided concavity. Axial T2-weighted images were used to measure the following variables: (1) the distance between the left psoas major muscle and the abdominal aorta; (2) the angle of the surgical access; (3) the distance between the psoas major muscle attachment point and the vertebral body's transverse axis; (4) the region of the psoas major muscle above the vertebrae; and (5) the width-to-thickness ratio. A statistical analysis of the measured parameters was done. The L2-5 segment in the supine position had a significantly longer window distance in the left convex and left concave groups than in the right lateral recumbent posture (P < 0.05). In all segments, the left concave group outperformed the left convex group, which was substantially higher in the right lateral recumbent posture than in the supine position (P < 0.05). After the position change, the spanning area was significantly higher compared to the same segment in the supine position. The psoas major muscle's morphology was stretched. The right lateral recumbent position limits access to OLIF for degenerative lumbar scoliosis, and the "safety window" for OLIF operation in the parietal region is smaller in the left convex group compared to the left concave group, posing a higher risk of intraoperative vascular and neurological injury.

Effects of posture changes on dynamic cerebral autoregulation during early pregnancy in women with obesity and/or sleep apnea.

The incidence of syncope during orthostasis increases in early human pregnancy, which may be associated with cerebral blood flow (CBF) dysregulation in the upright posture. In addition, obesity and/or sleep apnea per se may influence CBF regulation due to their detrimental impacts on cerebrovascular function. However, it is unknown whether early pregnant women with obesity and/or sleep apnea could have impaired CBF regulation in the supine position and whether this impairment would be further exacerbated in the upright posture. Dynamic cerebral autoregulation (CA) was evaluated using transfer function analysis in 33 women during early pregnancy (13 with obesity, 8 with sleep apnea, 12 with normal weight) and 15 age-matched nonpregnant women during supine rest. Pregnant women also underwent a graded head-up tilt (30° and 60° for 6min each). We found that pregnant women with obesity or sleep apnea had a higher transfer function low-frequency gain compared with nonpregnant women in the supine position (P = 0.026 and 0.009, respectively) but not normal-weight pregnant women (P = 0.945). Conversely, the transfer function low-frequency phase in all pregnancy groups decreased during head-up tilt (P = 0.001), but the phase was not different among pregnant groups (P = 0.180). These results suggest that both obesity and sleep apnea may have a detrimental effect on dynamic CA in the supine position during early pregnancy. CBF may be more vulnerable to spontaneous blood pressure fluctuations in early pregnant women during orthostatic stress compared with supine rest due to less efficient dynamic CA, regardless of obesity and/or sleep apnea.

Analysis of gravity effect on human blood flow and skin temperature through postural change

The blood flow of human body has much impact on the thermo-physiological response. When person change the posture, the gravity acts changes its direction and thus the blood flow can be changed. It is hypothesized that the gravitational effects of postural changes affect blood flow and skin temperature, which in turn affect comfort. To verify this, in the present study, a subject experiment focusing on postural changes was conducted for two conditions (Case 1 and Case 2). In the Case 1 experiment, the subjects were asked to raise their hands for 10 minutes after 30 minutes of rest in the chair-sitting position. As a result, significant skin temperature change were observed in the upper arm, forearm, and hand. The largest skin temperature change was observed in the hands, which showed a decrease in skin temperature of approximately 1.2 °C. The change had influence on the whole-body average value. In Case 2, the subjects were placed in the supine position for 10 minutes after 30 minutes of rest in the chair position. As a result, a decrease in skin temperature of approximately 1 °C was observed on the hands and 0.5 °C in the foot was observed.

Venous dynamics in anesthetized sheep govern postural-induced changes in cerebrospinal fluid pressure comparable to those in humans.

Sheep are popular large animals in which to model human disorders and to study physiological processes such as cerebrospinal fluid dynamics. However, little is known about vascular compensatory mechanisms affecting cerebrospinal fluid pressures during acute postural changes in sheep. Six female white Alpine sheep were anesthetized to investigate the interactions of the vascular and cerebrospinal fluid system by acquiring measurements of intracranial pressure and central and jugular venous pressure during passive postural changes induced by a tilt table. The cross-sectional area of the common jugular vein and venous blood flow velocity was recorded. Anesthetized sheep showed bi-phasic effects of postural changes on intracranial pressure during tilting. A marked collapse of the jugular vein was observed during head-over-body tilting; this is in accordance with findings in humans. Active regulatory effects of the arterial system on maintaining cerebral perfusion pressure were observed independent of tilting direction. Conclusion: Anesthetized sheep show venous dynamics in response to posture-induced changes in intracranial pressure that are comparable with those in humans.

EFFECT OF BODY POSTURE ON SEGMENTAL MULTIFREQUENCY BIOIMPEDANCE VARIABLES

Integrating measured data from different body postures is important for merging diverse clinical data from segmental multifrequency (SMF) bioimpedance analysis (BIA) and generating reference data. The purpose of this study was to evaluate the effects of changes in posture when measuring raw bioelectrical parameters based on body segment and frequency at various locations in healthy adults. In this study, InBody S10, an SMF-BIA device, was used, and the reliability of the device was verified using the intraclass correlation coefficient of repeated measurement results according to the change in the measurement posture. Measurements were performed in the supine, sitting, and standing positions, and resistance and reactance measured in the changed positions were compared. The supine position exhibited the highest resistance for all body segments and frequencies as well as the highest arm reactance. Resistance decreased monotonically with frequency. In contrast, the reactance of the legs and trunk in the supine position changed its phase above a critical frequency compared to that in the standing and sitting posture. Due to the influence of measurement posture on bioimpedance, regression models between different postures were proposed with body segments and frequencies that enable directly comparing or merging data obtained from various postures. The fit of the linear regression model, which can be used to convert the results from sitting and standing postures to the supine position, was 0.6 or greater. This study elucidates the effect of postural changes on SMF-BIA and enables combining SMF-BIA indicators with positional changes.

PREFACE

PREFACE

Impact of Postural Changes on Sinonasal Pressure After Endoscopic Endonasal Surgery

Postoperative management following endoscopic endonasal surgery (EES) is important to prevent cerebrospinal fluid leak and preserve the integrity of the nasoseptal flap. No consensus regarding an optimal posture in the postoperative period has been established. We hypothesized that sinonasal pressure (SNP) can represent intracranial pressure affecting the sellar floor in the absence of the sellar bone after surgery. This study provides evidence for the effect of postural changes and recommends optimal posture to reduce SNP following EES. The authors conducted a retrospective analysis of 50 patients who underwent reconstruction for skull base defects with nasoseptal flap after EES for resection of suprasellar tumor between March 2020 and August 2020. The Spiegelberg intracranial pressure probe was placed through the nostril over the nasoseptal flap. SNPs were measured in Fowler' (45° tilt) and supine positions, respectively, daily for the first 3days immediately after EES. For the first 3days after surgery, the mean SNP in Fowler' position (24.82mmHg; standard deviation, 12.23mmHg) was lower than that in the supine position (28.42mmHg; standard deviation, 12.33mmHg) (P<0.01). There were no significant differences in mean SNP for age, sex, tumor size, presence of hydrocephalus, and body mass index. There was a significant correlation between Fowler' position and a decrease in SNP measurements. Placing a patient in Fowler' position after surgery can decrease the SNP. We recommend that patients should be placed in a Fowler' position as an optimal position after surgery.

Effects of trunk posture on cardiovascular and autonomic nervous systems: A pilot study.

Objective: Although regular and moderate physical activity has been shown to improve the cardiovascular and autonomic nervous systems, little has been done to study the effects of postural changes in the movement on the heart and autonomic nervous system. To uncover changes in cardiac function and autonomic nerves induced by different underlying posture transitions and explore which trunk postures lead to chronic sympathetic activation. Therefore, this study investigated the effects of trunk posture on the cardiovascular and autonomic nervous systems. Methods: Twelve male subjects (age 24.7 ± 1.3) underwent this study. The non-invasive cardiac output NICOM monitoring equipment and the FIRSTBEAT system are used to dynamically monitor seven trunk postures in the sitting position simultaneously (neutral position, posterior extension, forward flexion, left lateral flexion, right lateral flexion, left rotation, right rotation). Each posture was maintained for 3min, and the interval between each movement was 3min to ensure that each index returned to the baseline level. Repeated analysis of variance test was used to compare and analyze the differences in human cardiac function, heart rate variability index, and respiratory rate under different postures. Results: Compared with the related indicators of cardiac output in a neutral trunk position: the cardiac index (CI) was significantly reduced in forwarding flexion and left rotation (3.48 ± 0.34 vs. 3.21 ± 0.50; 3.48 ± 0.34 vs. 3.21 ± 0.46, ΔL/(min/m2)) (p = 0.016, p = 0.013), cardiac output decreased significantly (6.49 ± 0.78 vs. 5.93 ± 0.90; 6.49 ± 0.78 vs. 6.00 ± 0.96, ΔL/min) (p = 0.006, p = 0.014), the stroke volume (stroke volume)decreased significantly (87.90 ± 15.10 vs. 81.04 ± 16.35; 87.90 ± 15.10 vs. 79.24 ± 16.83, Δml/beat) (p = 0.017, p = 0.0003); heart rate increased significantly in posterior extension (75.08 ± 10.43 vs. 78.42 ± 10.18, Δbeat/min) (p = 0.001); left rotation stroke volume index (SVI) decreased significantly (47.28 ± 7.97 vs. 46.14 ± 8.06, Δ ml/m2) (p = 0.0003); in the analysis of HRV-related indicators, compared with the neutral trunk position, the LF/HF of the posterior extension was significantly increased (1.90 ± 1.38 vs. 3.00 ± 1.17, p = 0.037), and the LF/HF of the forward flexion was significantly increased (1.90 ± 1.38 vs. 2.85 ± 1.41, p = 0.041), and the frequency-domain index LF/HF of right rotation was significantly increased (1.90 ± 1.38 vs. 4.06 ± 2.19, p = 0.008). There was no significant difference in respiratory rate (p > 0.05). Conclusion: A neutral trunk is the best resting position, and deviations from a neutral trunk position can affect the cardiovascular and autonomic nervous systems, resulting in decreased stroke volume, increased heart rate, and relative activation of sympathetic tone.

Acute effects of postural changes and lower body positive and negative pressure on the eye.

Introduction: Entry into weightlessness results in a fluid shift and a loss of hydrostatic gradients. These factors are believed to affect the eye and contribute to the ocular changes that occur in space. We measured eye parameters during fluid shifts produced by lower body negative pressure (LBNP) and lower body positive pressure (LBPP) and changes in hydrostatic gradient direction (supine-prone) in normal subjects to assess the relative effects of fluid shifts and hydrostatic gradient changes on the eye. Methods: Ocular parameters (intraocular pressure (IOP), ocular geometry, and optical coherence tomography measures) were measured in the seated, supine, and prone positions. To create a fluid shift in the supine and prone positions, the lower body chamber pressure ranged from -40 mmHg to +40 mmHg. Subjects maintained each posture and LBNP/LBPP combination for 15 min prior to data collection. A linear mixed-effects model was used to determine the effects of fluid shifts (as reflected by LBNP/LBPP) and hydrostatic gradient changes (as reflected by the change from seated to supine and from seated to prone) on eye parameters. Results: Chamber pressure was positively correlated with both increased choroidal thickness (β = 0.11 p = 0.01) and IOP (β = 0.06 p < 0.001). The change in posture increased IOP compared to seated IOP (supine β = 2.1, p = 0.01, prone β = 9.5, p < 0.001 prone) but not choroidal thickness. IOP changes correlated with axial length (R = 0.72, p < 0.001). Discussion: The effects of hydrostatic gradients and fluids shifts on the eye were investigated by inducing a fluid shift in both the supine and prone postures. Both hydrostatic gradients (posture) and fluid shifts (chamber pressure) affected IOP, but only hydrostatic gradients affected axial length and aqueous depth. Changes in choroidal thickness were only significant for the fluid shifts. Changes in hydrostatic gradients can produce significant changes in both IOP and axial length. Fluid shifts are often cited as important factors in the pathophysiology of SANS, but the local loss of hydrostatic gradients in the head may also play an important role in these ocular findings.

Effect of position on intracranial pressure and compliance: a cross-sectional study including 101 patients.

A better understanding of the effect of position on intracranial pressure (ICP) and compliance is important for the development of treatment strategies that can restore normal cerebrospinal fluid (CSF) dynamics. There is limited knowledge on the effect of position on intracranial compliance. In this cross-sectional study the authors tested the association of pulse amplitude (PA) with position and the day/night cycle. Additionally, they describe the postural ICP and PA changes of patients with "normal" ICP dynamics. This single-center retrospective study included patients with suspected and/or confirmed CSF dynamics abnormalities who had been examined with elective 24-hour ICP monitoring between October 2017 and September 2019. Patients had been enrolled in a short exercise battery including four positions: supine, lumbar puncture position in the left lateral decubitus position, sitting, and standing. Each position was maintained for 2 minutes, and mean ICP and PA were calculated for each position. The 24-hour day and night median ICP and PA data were also collected. Linear regression models were used to test the correlation of PA with position and day/night cycle. All linear regressions were corrected for confounders. The postural ICP monitoring results of patients without obvious ICP dynamics abnormality were summarized. One hundred one patients (24 males and 77 females) with a mean age of 39 ± 13years (mean ± standard deviation) were included in the study. The adjusted linear regression models demonstrated a significant association of ICP with position and day/night cycle, with upright (sitting and standing) and day ICP values lower than supine and night ICP values. The adjusted linear regression model was also significant for the association of PA with position and day/night cycle, with upright and day PA values higher than supine and night PA results. These associations were confirmed for patients with and without shunts. Patients without clear ICP dynamics abnormality had tighter control of their postural ICP changes than the other patients; however, the difference among groups was not statistically significant. This is the largest study investigating the effect of postural changes on intracranial compliance. The results of this study suggest that PA, as well as ICP, is significantly associated with posture, increasing in upright positions compared to that while supine. Further studies will be needed to investigate the mechanism behind this association.

A doppler ultrasonographic observation of interventional postural alterations on shear rates in peripheral arteries

Introduction and Aim: Drastic life style changes had resulted in increased reports of morbid atherosclerosis in young adults which is potentially a serious inflammatory condition which causes arteries to become harder and blocked with lipid accumulation known as plaques or atheroma. In the present study, effect of changes in posture on the resting shear rate (SR) was studied in arteries of both extremities. Materials and Methods: A cross sectional observational doppler ultrasound study was done in 30 healthy subjects, who satisfied a pre-set inclusion and exclusion criteria. The mean blood flow velocity (BV) and diameter were measured for both brachial arteries and femoral arteries in supine, sitting with leg fully extended, sitting with leg flexed at 90o, standing with and without slight head tilting of 10o postures after resting the subjects for 10 minutes in between each posture. The SR in various postures were calculated and tabulated. The data was statistically analysed using independent ‘t’ test and one-way ANOVA. Post Hoc test was applied for analysing statistical significance of SR in between postures. Results: The femoral artery showed significantly lower SR (P&lt;0.001) in all the postures studied when compared to brachial artery. On comparing posture within brachial and femoral artery by applying one-way ANOVA with Post Hoc test, only femoral showed significant difference in SR between postures. Conclusion: The postural effect in SR of arteries in lower limb may lead to alterations in the endothelium of arteries resulting in increased atherogenicity as compared to upper limb arteries.

Posture-induced intraocular pressure changes among patients with primary open angle glaucoma in a Nigerian Tertiary Hospital: Any implication for management.

To determine the effect of postural changes on intraocular pressure (IOP) among newly diagnosed patients with primary open-angle glaucoma (POAG). This was a cross-sectional observational study of 55 consecutive newly diagnosed patients with POAG attending Glaucoma clinics at a Federal Teaching Hospital in Abakaliki, Ebonyi state, from July to September 2017. Patients IOPs were measured in the sitting position, supine without a pillow, and supine with pillow positions using Perkin's handheld applanation tonometer. All data were analyzed with SPSS version 20.0. A total of 55 subjects were recruited comprising 30 (54.5%) males and 25 (45.5%) females, with a mean age of 50.13 ± 9.97 years and an age range of 30-79 years. The mean intraocular pressure was 27.54 ± 3.98 mmHg in the sitting position, 30.15 ± 4.41 mmHg in the supine with pillow position, and 35.22 ± 4.61 mmHg in the supine without pillow position. The mean difference of mean IOP of sitting compared to supine without the pillow was 7.68 ± 2.08 mmHg (P-value < 0.001, 95% CI: 7.12-8.24); sitting compared to supine with the pillow was 2.61 ± 1.49 mmHg (P-value < 0.001, 95% CI: 3.01-2.21), whereas supine without the pillow compared to supine with the pillow was 5.07 ± 2.24 mmHg (P-value 0.001, 95% CI: 4.47-5.68). IOP was lowest in the sitting position and highest in the supine without pillow position. There was a statistically significant reduction in IOP on the assumption of supine with pillow position compared to supine without pillow position. The use of thick pillows in supine positions (such as during sleep or relaxations) rather than lying supine without pillows may reduce IOP spikes in POAG patients. This may have a positive effect as regards treatment and progression of glaucoma.

Effects of postural changes on measured intraocular pressure and repeatability of PT-100 tonometer and agreement with applanation and indentation tonometry

Background: Repeatability and validity are important components of precision in any measurement system.Aim: This study aimed to determine the effect of change in head and neck position and body posture on the repeatability of intraocular pressure (IOP) measurements with PT-100 non-contact tonometer and compare with Goldmann, PT-100 and Schiøtz tonometer readings.Setting: Optometry clinic, Saudi Arabia.Methods: The IOP was measured in one selected eye of 84 healthy participants (mean aged 21.9 ± 2.0 years) using PT-100 in three head and body positions, Goldmann tonometer and Schiøtz on two separate visits, in a randomised fashion. Central corneal thickness (CCT) was measured using an ultrasound pachymeter. The repeatability, agreement and correlations between CCT and IOP differentials were assessed.Results: The IOP measured in three head and body positions with the PT-100 were similar and comparable to Goldmann IOPs in sessions one and two with 74% and 86% of PT-100 measurements within ±3 mmHg of the Goldmann tonometry, respectively, for sessions one and two. The Schiøtz tonometer-measured IOP was higher than the Goldmann IOPs (p 0.05) with 60% and 44% of Schiøtz IOPs within ±3 mmHg of the Goldmann tonometer IOP in sessions one and two, respectively. The limits of repeatability and reproducibility were best with the PT-100 and worst with the Schiøtz tonometer. The mean CCT (552±36 µm) was negatively correlated with differences between Goldmann and both PT-100 and Schiøtz-measured IOP.Conclusion: Postural changes did not affect the validity and repeatability of PT-100 readings. PT-100 measurements were interchangeable with Goldmann tonometer. Schiøtz overestimated Goldmann IOP in thicker corneas more than the PT-100.

THE RELATIONSHIP BETWEEN DRIVING DURATION AND THE INCIDENCE OF MYOFASCIAL PAIN SYNDROME IN THE UPPER TRAPEZIUS MUSCLE IN MICROBUS DRIVERS AT UBUNG TERMINAL

ABSTRACT&#x0D; &#x0D; Myofascial pain syndrome is commonly felt by drivers who perform activities in a static and repetitive manner for long durations. Myofascial pain syndrome is caused by a change in cervical posture, leading to excessive burden and tightness in the upper trapezius muscle. Complaints are described as pain due to the suppression of nociceptor nerve fibers in the neck and shoulder area. The objective of this study was to determine the relationship between driving duration and the incidence of myofascial pain syndrome in the upper trapezius muscle in microbus drivers at Ubung Terminal, specifically drivers majoring the Singaraja-Denpasar/Denpasar-Singaraja route. The sampling technique used in this study was consecutive sampling. This study used an observational method with a cross-sectional design. Data were collected from 64 microbus drivers majoring the Singaraja-Denpasar/Denpasar-Singaraja route at Ubung terminal. The results showed a significant relationship between driving duration and myofascial pain syndrome with a correlation of 0.426 and a p-value of 0.000 (p &lt;0.05). It can be concluded that there is a relationship between driving duration and the incidence of myofascial pain syndrome in the upper trapezius muscle in microbus drivers at Ubung Terminal. In the future, follow-up research can be conducted to see the long-term effects of changes in posture and driving duration, and the sample size can be increased by taking the entire population of terminals in Bali.&#x0D; &#x0D; Keywords: Myofascial pain syndrome, driving duration, visual analogue scale

Wrist Angle Estimation With a Musculoskeletal Model Driven by Electrical Impedance Tomography Signals

Wrist kinematics estimation with muscle signals is a key issue in the field of wearable robots. In this study, we proposed a musculoskeletal-based-method driven by the Electrical Impedance Tomography (EIT) signals for continuously estimating wrist flexion/extension angles. The EIT-based interface can construct the conductivity distribution of the anatomical cross-sectional plane with a soft elastic sensing front-end, which is designed by our group. The estimation method took advantage of the flexor/extensor muscles' spatial information detected by the EIT-based interface to map the signals to the wrist angles. The whole model was designed with a musculoskeletal kinematic model, a muscular geometry model, and a mapping function between the EIT signals and the muscle morphological parameters. We validated the proposed method with intra-subject, inter-subject, and inter-posture cross-validations on 14 subjects in total. The results were compared with two data-driven algorithms (Lasso and kernel-based SVM). The muscle-model-based method was more robust to training data sizes than the other two methods. It achieved an average R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of 0.97 with 1:10 intra-subject CV and 0.91 with 2:12 inter-subject CV. The model also quickly overcame the effects of posture changes with a short-time feature update. The results of our study are comparable, if not better, to that of state-of-the-art. Future endeavors are worth being paid in this direction to get more promising outcomes.