Head Rotation Angles Research Articles

Methods for Detecting the Patient’s Pupils’ Coordinates and Head Rotation Angle for the Video Head Impulse Test (vHIT), Applicable for the Diagnosis of Vestibular Neuritis and Pre-Stroke Conditions

In the contemporary era, dizziness is a prevalent ailment among patients. It can be caused by either vestibular neuritis or a stroke. Given the lack of diagnostic utility of instrumental methods in acute isolated vertigo, the differentiation of vestibular neuritis and stroke is primarily clinical. As a part of the initial differential diagnosis, the physician focuses on the characteristics of nystagmus and the results of the video head impulse test (vHIT). Instruments for accurate vHIT are costly and are often utilized exclusively in healthcare settings. The objective of this paper is to review contemporary methodologies for accurately detecting the position of pupil centers in both eyes of a patient and for precisely extracting their coordinates. Additionally, the paper describes methods for accurately determining the head rotation angle under diverse imaging and lighting conditions. Furthermore, the suitability of these methods for vHIT is being evaluated. We assume the maximum allowable error is 0.005 radians per frame to detect pupils’ coordinates or 0.3 degrees per frame while detecting the head position. We found that for such conditions, the most suitable approaches for head posture detection are deep learning (including LSTM networks), search by template matching, linear regression of EMG sensor data, and optical fiber sensor usage. The most relevant approaches for pupil localization for our medical tasks are deep learning, geometric transformations, decision trees, and RASNAC. This study might assist in the identification of a number of approaches that can be employed in the future to construct a high-accuracy system for vHIT based on a smartphone or a home computer, with subsequent signal processing and initial diagnosis.

Multimodal Learning Engagement Assessment System: An Innovative Approach to Optimizing Learning Engagement

In the realm of global smart education, optimizing classroom learning efficiency is paramount. This study harnesses cutting-edge technology to delve into learning engagement dynamics. Leveraging the XGBoost model, 468 facial and bodily features are captured in real-time, offering insights into student behavior. The ResNet neural transformation network and PNP algorithm discern facial expressions, body movements, and head rotation angles. Through a fuzzy comprehensive evaluation method, proportions of these factors are delineated for objective assessment. Empirical validation involves scrutinizing final exam scores of 234 college students. Comparative analyses reveal a significant correlation between classroom participation and performance (p-value = 0.034). Results underscore the impact of real-time judgment on learning efficiency and highlight the potency of multimodal fusion in assessing engagement comprehensively. Practical application validates system effectiveness, offering insights for educational stakeholders and contributing to the evolution of smart education.

Examining How Interaural Differences Owing to Head Rotation during Walking Improve the Distance of Auditory Obstacle Perceptions among Individuals with Visual Impairment: A Case Study in Small-Scale Blind Group.

The ability of individuals with visual impairment to recognize an obstacle by hearing is called "obstacle sense". This ability is facilitated while they are moving, though the exact reason remains unknown. This study aims to clarify which acoustical factors may contribute to obstacle sense, especially obstacle distance perception. First, we conducted a comparative experiment regarding obstacle distance localization by individuals who are blind (N = 5, five men with blindness aged 22-42 (average: 29.8)) while they were standing and walking. The results indicate that the localized distance was more accurate while walking than while standing. Subsequently, the head rotation angle while walking and acoustic characteristics with respect to obstacle distance and head rotation angle were investigated. The peaks of the absolute head rotation angle during walking ranged from 2.78° to 11.11° (average: 6.55°, S.D.: 2.05°). Regarding acoustic characteristics, acoustic coloration occurred, and spectral interaural differences and interaural intensity differences were observed in the blind participants (N = 4, four men including two blind and two control sighted persons aged 25-38 (average: 30.8)). To determine which acoustic factors contribute, we examined the threshold of changes for interaural differences in time (ITD) and intensity (IID) (N = 11, seven men and four women with blindness aged 21-35 (average: 27.4)), as well as coloration (ICD) (N = 6, seven men and a woman with blindness aged 21-38 (average: 29.9))-depending on the head rotation. Notably, ITD and IID thresholds were 86.2 μs and 1.28 dB; the corresponding head rotation angles were 23.5° and 9.17°, respectively. The angle of the ICD threshold was 6.30° on average. Consequently, IID might be a contributing factor and ICD can be utilized as the cue facilitating the obstacle distance perception while walking.

UHead

The focus of Advanced driver-assistance systems (ADAS) is extending from the vehicle and road conditions to the driver because the driver's attention is critical to driving safety. Although existing sensor and camera based methods can monitor driver attention, they rely on specialised hardware and environmental conditions. In this paper, we aim to develop an effective and easy-to-use driver attention monitoring system based on UWB radar. We exploit the strong association between head motions and driver attention and propose UHead that infers driver attention by monitoring the direction and angle of the driver's head rotation. The core idea is to extract rotational time-frequency representation from reflected signals and to estimate head rotation angles from complex head reflections. To eliminate the dynamic noise generated by other body parts, UHead leverages the large magnitude and high velocity of head rotation to extract head motion information from the dynamically coupled information. UHead uses a bilinear joint time-frequency representation to avoid the loss of time and frequency resolution caused by windowing of traditional methods. We also design a head structure-based rotation angle estimation algorithm to accurately estimate the rotation angle from the time-varying rotation information of multiple reflection points in the head. Experimental results show that we achieve 12.96° median error of 3D head rotation angle estimation in real vehicle scenes.

Design and evaluation of pneumatic impact‐twisting combined walnut fixed posture shell‐breaking mechanism

AbstractThe traditional walnut shelling methods, involving single‐stage or secondary processes, face challenges such as increased costs, uncertainties in shell positioning, and irregular crack expansion. To address these issues, this article introduces an innovative pneumatic impact‐twisting combined shelling method based on walnut fixed posture. The shelling mechanism design and orthogonal test were conducted, optimizing parameters like spring wire diameter (A), pressing head rotation angle (B), and cylinder locking air pressure (C) using evaluation criteria such as superior‐grade rate, intermediate‐grade rate, broken kernel rate, and shelling rate. Results indicate that the optimal shelling effect is achieved with a 3.5 mm steel spring wire diameter, a 100° downward pressing head rotation angle, and a 0.6 MPa cylinder locking air pressure on the pressure arm. The corresponding rates are as follows: superior‐grade rate 29.49%, intermediate‐grade rate 52.54%, broken kernel rate 10.14%, and shelling rate 91.04%. This study demonstrates that the pneumatic impact‐twisting combined walnut fixed posture shelling method improves post‐shelling quality, offering new design concepts for walnut shelling equipment.Practical ApplicationsThis introduces an innovative method that combines impact with twisting, and a pneumatic impact‐twisting combined walnut fixed posture shell‐breaking test device has been developed. Mechanical analysis was conducted for each stage of shell‐breaking. The research indicates that the pneumatic impact‐twisting combined method can enhance the production quality of walnut kernels after shell‐breaking. The test results indicate an improvement in the yield of 1/2 and 1/4 kernels compared to existing shell‐breaking methods. The inventive design of this shell‐breaking module contributes to the walnut kernel quality in the shell‐breaking production line, offering new methods and concepts for the design and advancement of walnut shell‐breaking devices.

A Novel Combined Method for Measuring the Three-Dimensional Rotational Angle of a Spherical Joint.

To improve the measurement accuracy of the three-dimensional rotation angle of a spherical joint, a novel approach is proposed in this study, which combines magnetic detection by a Hall sensor and surface feature identification by an eddy current sensor. Firstly, a permanent magnet is embedded in the ball head of a spherical joint, and Hall sensors are set and distributed in the ball socket to measure the variation in the magnetic flux density when the spherical joint rotates, which are related to the 3D rotation angle. In order to further improve the measurement accuracy and robustness, we also set grooves on the ball head and use eddy current sensors to synchronously identify the rotation angle of the ball head. After the combination of two signals is performed, a measurement model is established using the RBF neural network by training, and the real-time measurement of the 3D rotation angle of the spherical joint is realized. The feasibility and superiority of this method are validated through experiments. The experimental results indicate that the measurement accuracy is substantially promoted compared to the preliminary measurement scheme based on spherical coding; the average measurement error of the single axis is reduced by 9'9″. The root mean square errors for the measurements of the 3D rotation angles in this proposed method are as follows: pitch angle α has an error of 1'8″, yaw angle β has an error of 2'15″, and roll angle γ has an error of 29'6″.

DeepSTI: Towards tensor reconstruction using fewer orientations in susceptibility tensor imaging.

Susceptibility tensor imaging (STI) is an emerging magnetic resonance imaging technique that characterizes the anisotropic tissue magnetic susceptibility with a second-order tensor model. STI has the potential to provide information for both the reconstruction of white matter fiber pathways and detection of myelin changes in the brain at mm resolution or less, which would be of great value for understanding brain structure and function in healthy and diseased brain. However, the application of STI in vivo has been hindered by its cumbersome and time-consuming acquisition requirement of measuring susceptibility induced MR phase changes at multiple head orientations. Usually, sampling at more than six orientations is required to obtain sufficient information for the ill-posed STI dipole inversion. This complexity is enhanced by the limitation in head rotation angles due to physical constraints of the head coil. As a result, STI has not yet been widely applied in human studies in vivo. In this work, we tackle these issues by proposing an image reconstruction algorithm for STI that leverages data-driven priors. Our method, called DeepSTI, learns the data prior implicitly via a deep neural network that approximates the proximal operator of a regularizer function for STI. The dipole inversion problem is then solved iteratively using the learned proximal network. Experimental results using both simulation and in vivo human data demonstrate great improvement over state-of-the-art algorithms in terms of the reconstructed tensor image, principal eigenvector maps and tractography results, while allowing for tensor reconstruction with MR phase measured at much less than six different orientations. Notably, promising reconstruction results are achieved by our method from only one orientation in human in vivo, and we demonstrate a potential application of this technique for estimating lesion susceptibility anisotropy in patients with multiple sclerosis.

Feasibility of an inertial measurement unit sensor-based guiding system for benign paroxysmal positional vertigo treatment: A pilot study

Performing an accurate canalith repositioning procedure (CRP) is important for treating benign paroxysmal positional vertigo, because inadequate rotational head angles can result in ineffective otolith mobilization and consequent treatment failure. Specialists-guided Epley maneuver reportedly had mean errors of 13.7°–24.4° while they were significantly larger (40.0°–51.5°) when self-administered. Similar results were obtained for the Barbeque maneuver: mean errors were 9.2°–13.0° by the specialists while they were significantly larger (22.9°–28.6°) when self-administered. Our study aimed to validate the feasibility of an inertial measurement unit sensor-based CRP (IMU-CRP) by analyzing the differences in accuracy in the rotational angles, comparing them with education-based conventional CRP (EDU-CRP). A pilot validation was also performed by analyzing the treatment success rate of IMU-CRP in patients with BPPV. This single-institution prospective, comparative effectiveness study examined 19 participants without active vertigo or prior knowledge of benign paroxysmal positional vertigo and CRP. Participants conducted the Epley and Barbeque roll maneuvers without and with auditory guidance (EDU-CRP vs. IMU-CRP, respectively) twice, and head rotation accuracies were compared. Differences in target angles based on the American Academy of Otolaryngology-Head and Neck Surgery guidelines were considered errors. For BPPV participants, treatment success was assessed based on the presence or absence of nystagmus, vertigo, and dizziness. For all the Epley and Barbeque roll maneuvers steps, the absolute errors were smaller for IMU- than for EDU-CRPs, with significant differences in steps 2–4 and 3–6 of the Epley and Barbeque roll maneuvers, respectively. A learning effect was found in steps 4 and 5 of the Barbeque roll maneuver but not in the Epley maneuver. The treatment success rates after 1 h were 71.4% and 100% for the Epley and Barbeque roll maneuvers, respectively. Real-time feedback on head rotation angles induced more appropriate movements in the Epley and Barbeque roll maneuvers. A guiding device based on head monitoring providing real-time auditory feedback may increase the self-administered CRP success rates in treating benign paroxysmal positional vertigo.

Effect of head rotation on two-dimensional cephalometric measurements using cone beam-computed tomography.

The purpose of this study was to identify the variation of bi-dimensional cephalometric measurements following real head rotation. Thirty cone beam-computed tomography (CBCT) head films were oriented according to three axes: horizontal Frankfort plane, transverse bi-orbital plane, and Opisthion-Nasion median plane. Axial rotation of 2°, 4°, 6°, and 8° from the Odontoïdale point were performed. Horizontal and vertical linear and angular measurements were studied on lateral cephalograms derived from each rotation T0, T2, T4, T6, and T8. A paired t-test was applied to compare the measurements between T0 and each rotational angle. Of the 18 measurements, 55% showed statistically significant differences (P < 0.05) and 22% showed clinically significant differences, mostly at T6 and T8. Horizontal linear measurements Ba-A and N-Ba decreased, and vertical linear measurement G-Sn increased gradually, as the angle of head rotation increased. Angular measurements studied did not vary. Head malpositions during X-ray acquisition should be avoided and rotated lateral CBCT cephalograms should be corrected and recentered to prevent any variation in linear measurements.

An integrated neural network model for eye-tracking during human-computer interaction.

Improving the efficiency of human-computer interaction is one of the critical goals of intelligent aircraft cockpit research. The gaze interaction control method can vastly reduce the manual operation of operators and improve the intellectual level of human-computer interaction. Eye-tracking is the basis of sight interaction, so the performance of eye-tracking will directly affect the outcome of gaze interaction. This paper presents an eye-tracking method suitable for human-computer interaction in an aircraft cockpit, which can now estimate the gaze position of operators on multiple screens based on face images. We use a multi-camera system to capture facial images, so that operators are not limited by the angle of head rotation. To improve the accuracy of gaze estimation, we have constructed a hybrid network. One branch uses the transformer framework to extract the global features of the face images; the other branch uses a convolutional neural network structure to extract the local features of the face images. Finally, the extracted features of the two branches are fused for eye-tracking. The experimental results show that the proposed method not only solves the problem of limited head movement for operators but also improves the accuracy of gaze estimation. In addition, our method has a capture rate of more than 80% for targets of different sizes, which is better than the other compared models.

Drone Aided Thermal Mapping for Selective Irrigation of Localized Dry Spots

We report a smart irrigation system that allows selective irrigation of localized dry spots in an agricultural field. The proposed irrigation system uses a quadcopter drone equipped with a Thermal Infrared (TIR) camera and a GPS module to generate georeferenced thermal images that indicate the area and location of the dry spots in a survey area. Drones navigate and acquire aerial thermal images, which are then processed by an onboard edge intelligence module along with flight data (GPS coordinates, altitude, and drone direction). Smart sprinklers deployed on the field are able to wirelessly receive the coordinates of dry spots so they can be irrigated selectively. A terrestrial edge unit generates an irrigation pattern for the smart sprinklers using a pre-trained machine learning (ML) model to generate an irrigation pattern by varying the head rotation angle ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta$ </tex-math></inline-formula> ) and the water flow control valve rotation angle( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\emptyset$ </tex-math></inline-formula> ) of the smart sprinkler.

Anatomical relationship between the omohyoid muscle and the internal jugular vein on ultrasound guidance

BackgroundInternal jugular vein catheterization is widely used in clinical practice, and there are many related studies on internal jugular vein catheterization. However, the omohyoid muscle, which is adjacent to the internal jugular vein, is a rarely mentioned muscle of the infrahyoid muscles group. The purpose of this study is to explore the anatomical relationship between the omohyoid muscle and the internal jugular vein on ultrasound guidance and provide a theoretical reference for jugular puncture and catheterization.MethodsThe study included 30 volunteers. The volunteer’s head lay in the neutral position and was then turned to the left at an angle of 30°, 45° and 60° with the bed surface, as verified using an adjustable protractor. A high-frequency ultrasound probe (6–14 Hz) was used to examine the plane of the apex of sternocleidomastoid triangle (PAST), the triangle consists of anatomical landmarks: a base was clavicle, its sides – heads of sternocleidomastoid muscle. And the plane of the middle of sternocleidomastoid triangle(PMST) which was a horizontal line, connecting midpoints of both sides. The right omohyoid muscle (OM) and the right internal jugular vein (IJV) were observed and recorded for statistical analysis.ResultsThere were statistically significant differences in the number of overlapping cases of OM and IJV at each head rotation angle between the PAST and PMST groups. There were statistically significant differences between the angles which OM and IJV centre point line and the left horizontal position of the PAST and PMST at different body angles.ConclusionThe traditional middle route puncture point is the apex of the sternocleidomastoid triangle, which can effectively avoid injury to the omohyoid muscle, to an extent.Trail registrationChiCTR2000034233, Registered 29/06/2020. www. Chinese Clinical Trial Registry.gov.

Quantitative effects of head rotation angle on apnea hypopnea index in positional obstructive sleep apnea \u2013 a preliminary case series

ObjectivesQuantify the effects of head rotation and head incline on obstructive sleep apnea (OSA) severity.DesignSingle-arm, intervention study.SettingPulmonary specialty clinic.Case presentationTen adults diagnosed with positional OSA ranging from 32 to 64 years of age 6 females, 4 males reporting persistent daytime sleepiness and health issues with consistent use of CPAP.InterventionStandard polysomnography with a head angle sensor attached to the forehead and coaching to fall asleep with head at various rotation and incline angles and torso in supine and non-supine positions.MeasurementsOSA severity was scored according to American Academy of Sleep Medicine guidelines. Apnea hypopnea index (AHI) and peripheral capillary oxygen (SpO2) saturation were measured during each sleep epoch of unique head rotation, head incline, and torso position.ResultsTwo participants (1 with no apneas and 1 with central sleep apnea) were excluded. Among the remaining 8 participants, average reduction in peak AHI was 66% (range 18–88%) with head rotation ≤ 20° above the horizon compared with > 20° above the horizon. The average of peak AHI values with head rotation ≤ 20° was significantly lower than with head rotation > 20° (20.0 vs 45.3, P = 0.002). Minimum SpO2 was significantly higher for head rotation ≤ 20° compared with > 20° (mean: 90.6% vs 84.3%, P = 0.03). In the torso supine position, average peak AHI was significantly lower with head rotation ≤ 20° compared with > 20° (7.1 vs 52.1, P < 0.001). In the torso non-supine position, lower average peak AHI with head rotation ≤ 20° was not statistically significant (22.3 vs 38.4, P = 0.09).ConclusionThese results support further exploration of maintaining head position ≤ 20° above the horizon to minimize AHI and oxygen desaturation in OSA patients.Trial registrationApnea Hypopnea Index Severity Versus Head Position During Sleep.ClinicalTrials.gov Identifier: NCT04086407 September 11, 2019 Registered retrospectively.

Multi-Objective Optimization Study on Ligament Characteristics of Neck Finite Element Model

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;This paper proposes a new method to improve the fit between the neck finite element calculation results and the experimental data through multi-objective optimization of cervical ligament parameters. By refining a previously established finite element model of the neck and improving the fineness of vertebrae and other structures, a new finite element model of the neck was established. The new model adopts the same material property parameters as the previous model. We performed many simulation calculations, each time only one ligament in the model was removed, leaving other structures unchanged. By observing the changes in the angle of the neck joints in the neck torsion experiment of the model before and after the ligament was removed, the influence of the ligament on the model was obtained. The six ligaments with the largest contribution are selected, and their laxity is optimized for multi-objective research, and the optimal solution for the laxity of the selected ligaments is obtained. The optimized ligament relaxation parameters are applied to the neck model to verify the effectiveness of the Panjabi’s experiment. The calculated joint angle is in good agreement with the experimental data. Furthermore, using the forward flexion and extension motion angles of Nightingale et al. 2007 model to simulate and verify the present model, the calculated value is basically consistent with the experimental value. In order to further verify the effectiveness of the established neck model, the head and neck drop experiment, the front collision and rear collision experiment of the volunteer trolley were used for simulation verification. The results show that the calculated values of head centroid displacement, acceleration, and head rotation angle fit well with the experimental values.&lt;/div&gt;&lt;/div&gt;

Quantitative Analysis of Dynamic Subacromial Ultrasonography: Reliability and Influencing Factors.

Objective: Current imaging methods used to examine patients with subacromial impingement syndrome (SIS) are limited by their semi-quantitative nature and their capability of capturing dynamic movements. This study aimed to develop a quantitative analytic model to assess subacromial motions using dynamic ultrasound and to examine their reliability and potential influencing factors. Method: We included 48 healthy volunteers and examined their subacromial motions with dynamic ultrasound imaging. The parameters were the minimal vertical acromiohumeral distance, rotation radius, and degrees of the humeral head. The generalized estimating equation (GEE) was used to investigate the impact of different shoulder laterality, postures, and motion phases on the outcome. Result: Using the data of the minimal vertical acromiohumeral distance, the intra-rater and inter-rater reliabilities (intra-class correlation coefficient) were determined as 0.94 and 0.88, respectively. In the GEE analysis, a decrease in the minimal vertical acromiohumeral distance was associated with the abduction phase and full-can posture, with a beta coefficient of −0.02 cm [95% confidence interval (CI), −0.03 to −0.01] and −0.07 cm (95% CI, −0.11 to −0.02), respectively. The abduction phase led to a decrease in the radius of humeral rotation and an increase in the angle of humeral rotation, with a beta coefficient of −1.28 cm (95% CI, −2.16 to −0.40) and 6.60° (95% CI, 3.54–9.67), respectively. A significant negative correlation was observed between the rotation angle and radius of the humeral head and between the rotation angle and the minimal vertical acromiohumeral distance. Conclusion: Quantitative analysis of dynamic ultrasound imaging enables the delineation of subacromial motion with good reliability. The vertical acromiohumeral distance is the lowest in the abduction phase and full-can posture, and the rotation angle of the humeral head has the potential to serve as a new parameter for the evaluation of SIS.

Impact of Bone Cement Augmentation on the Fixation Strength of TFNA Blades and Screws.

Background and Objectives: Hip fractures constitute the most debilitating complication of osteoporosis with steadily increasing incidences in the aging population. Their intramedullary nailing can be challenging because of poor anchorage in the osteoporotic femoral head. Cement augmentation of Proximal Femoral Nail Antirotation (PFNA) blades demonstrated promising results by enhancing cut-out resistance in proximal femoral fractures. The aim of this study was to assess the impact of augmentation on the fixation strength of TFN-ADVANCEDTM Proximal Femoral Nailing System (TFNA) blades and screws within the femoral head and compare its effect when they are implanted in centre or anteroposterior off-centre position. Materials and Methods: Eight groups were formed out of 96 polyurethane low-density foam specimens simulating isolated femoral heads with poor bone quality. The specimens in each group were implanted with either non-augmented or cement-augmented TFNA blades or screws in centre or anteroposterior off-centre positions, 7 mm anterior or posterior. Mechanical testing was performed under progressively increasing cyclic loading until failure, in setup simulating an unstable pertrochanteric fracture with a lack of posteromedial support and load sharing at the fracture gap. Varus-valgus and head rotation angles were monitored. A varus collapse of 5° or 10° head rotation was defined as a clinically relevant failure. Results: Failure load (N) for specimens with augmented TFNA head elements (screw/blade centre: 3799 ± 326/3228 ± 478; screw/blade off-centre: 2680 ± 182/2591 ± 244) was significantly higher compared with respective non-augmented specimens (screw/blade centre: 1593 ± 120/1489 ± 41; screw/blade off-centre: 515 ± 73/1018 ± 48), p < 0.001. For both non-augmented and augmented specimens failure load in the centre position was significantly higher compared with the respective off-centre positions, regardless of the head element type, p < 0.001. Augmented off-centre TFNA head elements had significantly higher failure load compared with non-augmented centrally placed implants, p < 0.001. Conclusions: Cement augmentation clearly enhances the fixation stability of TFNA blades and screws. Non-augmented blades outperformed screws in the anteroposterior off-centre position. Positioning of TFNA blades in the femoral head is more forgiving than TFNA screws in terms of failure load.

Effect of physical therapy intervention on thickness and ratio of the sternocleidomastoid muscle and head rotation angle in infants with congenital muscular torticollis: A randomized clinical trial (CONSORT).

Background:Early diagnosis as well as treatment is important in management of congenital muscular torticollis (CMT). The purpose of this study was to find an effective physical therapy modality to improve the sternocleidomastoid (SCM) muscle thickness, the ratio of the SCM muscle thickness on the affected side to that on the non-affected side (A/N ratio), and head rotation in infant under 3 months of age diagnosed with CMT.Methods and analysis:A single-blind, randomized clinical trial was conducted. Participants were assigned in one of the 3 study groups through randomization. The treatment was performed 3 times a week for 30 minutes until the head tilt was ≤5 degrees. Group 1 was treated by handling for active or active-assist movement, group 2 was treated with passive stretching, and group 3 was treated with thermotherapy. For general characteristics, a χ2 test and 1-way analysis of variance were used. Intragroup differences were analyzed using a paired t test, and intergroup differences were analyzed using an age-adjusted analysis of covariance.Results:After the intervention, there was no significant difference between groups in terms of SCM thickness on the affected side and A/N ratio (P > .05). Degree of head rotation on the affected side showed significant differences between groups (P < .05), with Group 2 showing significantly better results than group 1 and group 3 (P < .05, both).Conclusion:Passive stretching treatment was more effective than other treatments of this study for improvement in degree of head rotation in CMT infants under 3 months of age.Trial registration:The trial is registered at the Institutional Review Board of Sahmyook University (IRB number, 2-7001793-AB-N-012019103HR) and the Clinical Research Information Service (CRiS; registry number, KCT0004862)

Importance of passive muscle, skin, and adipose tissue mechanical properties on head and neck response in rear impacts assessed with a finite element model

Objective The objective of this study was to improve head-neck kinematic predictions of a contemporary finite element (FE) head-neck model, assessed in rear impact scenarios (3–10 g), by including an accurate representation of the skin, adipose tissue, and passive muscle mechanical properties. The soft tissues of the neck have a substantial contribution to kinematic response, with the contribution being inversely proportional to the impact severity. Thus accurate representation of these passive tissues is critical for the assessment of kinematic response and the potential for crash induced injuries. Contemporary Human Body Models (HBMs) often incorporate overly stiff mechanical properties of passive tissues for numerical stability, which can affect the predicted kinematic response of the head and neck. Methods Soft tissue material properties including non-linearity, compression-tension asymmetry, and viscoelasticity were implemented in constitutive models for the skin, adipose, and passive muscle tissues, based on experimental data in the literature. A quasi-linear viscoelastic formulation was proposed for the skin, while a phenomenological hyper-viscoelastic model was used for the passive muscle and adipose tissues. A head-neck model extracted from a contemporary FE HBM was updated to include the new tissue models and assessed using head rotation angle for rear impact scenarios (3 g, 7 g, and 10 g peak accelerations), and compared to postmortem human surrogate (PMHS) data for 7 g impacts. Results The head rotation angle increased with the new material models for all three rear impact cases: (3 g: +43%, 7 g: +52%, 10 g: +71%), relative to the original model. The increase in head rotation was primarily attributed to the improved skin model, with the passive muscle being a secondary contributor to the increase in response. A 52% increase in head rotation for the 7 g impact improved the model response with respect to PMHS data, placing it closer to the experimental average, compared to the original model. Conclusions The improved skin, adipose tissue, and passive muscle material model properties, based on published experimental data, increased the neck compliance in rear impact, with improved correspondence to published PMHS test data for medium severity impacts. Future studies will investigate the coupled effect of passive and active muscle tissue for low severity impacts.

Gaze, head and eye movements during somersaults with full twists.

Somersaults with or without twists are the most important elements in sports such as gymnastics or trampolining. Moreover, to perform elements with the highest possible difficulty gymnasts should show good form and execution during the flight phase. In order to ensure perfect body control and a safe landing, gaze behavior has been proven to be crucial for athletes to orientate in the air. As eye movement and head movement are closely coordinated, both must be examined while investigating gaze behavior. The aim of the current study is to analyze athletes' head motion and gaze behavior during somersaults with full twists. 15 skilled trampoline gymnasts performed back straight somersaults with a full twist (back full) on the trampoline. Eye movement and head movement were recorded using a portable eye-tracking device and a motion capture suit. The results indicate that gymnasts use the trampoline bed as a fixation point for orientation and control the back full, whereas the fixation onsets for athletes of a better performance class occur significantly later. A strong coordination between gymnasts' eye movement and head movement could be determined: stabilizing the gaze during the fixation period, the eyes move in combination with the head against the twisted somersault direction to counteract the whole body rotation. Although no significant differences could be found between the performance classes with regard to the maximum axial head rotations and maximum head extensions, there seems to be a trend that less skilled gymnasts need orientation as early as possible resulting in greater head rotation angles but a poorer execution.

Blind footballers direct their head towards an approaching ball during ball trapping

In blind football, players predict the sound location of a ball to underpin the success of ball trapping. It is currently unknown whether blind footballers use head movements as a strategy for trapping a moving ball. This study investigated characteristics of head rotations in blind footballers during ball trapping compared to sighted nonathletes. Participants performed trapping an approaching ball using their right foot. Head and trunk rotation angles in the sagittal plane, and head rotation angles in the horizontal plane were measured during ball trapping. The blind footballers showed a larger downward head rotation angle, as well as higher performance at the time of ball trapping than did the sighted nonathletes. However, no significant differences between the groups were found with regards to the horizontal head rotation angle and the downward trunk rotation angle. The blind footballers consistently showed a larger relative angle of downward head rotation from an early time point after ball launching to the moment of ball trapping. These results suggest that blind footballers couple downward head rotation with the movement of an approaching ball, to ensure that the ball is kept in a consistent egocentric direction relative to the head throughout ball trapping.