Identification of Gait Motion Patterns Using Wearable Inertial Sensor Network

Gait signifies the walking pattern of an individual. It may be normal or abnormal, depending on the health condition of the individual. This paper considers the development of a gait sensor network system that uses a pair of wireless inertial measurement unit (IMU) sensors to monitor the gait cycle of a user. The sensor information is used for determining the normality of movement of the leg. The sensor system places the IMU sensors on one of the legs to extract the three-dimensional angular motions of the hip and knee joints while walking. The wearable sensor is custom-made at San Diego State University with wireless data transmission capability. The system enables the user to collect gait data at any site, including in a non-laboratory environment. The paper also presents the mathematical calculations to decompose movements experienced by a pair of IMUs into individual and relative three directional hip and knee joint motions. Further, a new approach of gait pattern classification based on the phase difference angles between hip and knee joints is presented. The experimental results show a potential application of the classification method in the areas of smart detection of abnormal gait patterns.

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Prefabricated Patient-Matched Cranial Implants for Reconstruction of Large Skull Defects

Journal of Central Nervous System Disease ◽

10.4137/jcnsd.s11106 ◽

2013 ◽

Vol 5 ◽

pp. JCNSD.S11106 ◽

Cited By ~ 6

Author(s):

Jarle Sundseth ◽

Jon Berg-Johnsen

Keyword(s):

Bone Cement ◽

Three Dimensional ◽

Deep Infection ◽

Skull Defects ◽

Cranial Defect ◽

Custom Made ◽

Dimensional Reconstruction ◽

Cranial Implant ◽

Cranial Implants ◽

The Individual

Cranial defects can be caused by injury, infection, or tumor invasion. Large defects should be reconstructed to protect the brain and normalize the cerebral hemodynamics. The conventional method is to cover the defect with bone cement. Custom-made implants designed for the individual patient are now available. We report our experience with one such product in patients with large cranial defects (>7.6 cm in diameter). A CT scan with 2 mm slices and a three-dimensional reconstruction were obtained from the patient. This information was dispatched to the company and used as a template to form the implant. The cranial implant was received within four weeks. From 2005 to 2010, custom-made cranial implants were used in 13 patients with large cranial defects. In 10 of the 13 patients, secondary deep infection was the cause of the cranial defect. All the implants fitted well or very well to the defect. No infections were seen after implantation; however, one patient was reoperated on for an epidural hematoma. A custom-made cranial implant is considerably more expensive than an implant made of bone cement, but ensures that the defect is optimally covered. The use of custom-made implants is straightforward and timesaving, and they provide an excellent medical and cosmetic result.

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Three-Dimensional Morphometry of Normal Japanese Knees For Designing Total Knee Arthroplasty

10.21203/rs.3.rs-970782/v1 ◽

2021 ◽

Author(s):

Tetsuya Tomita ◽

Masahiko Suzuki ◽

Takashi Nakamura ◽

Keinosuke Ryu ◽

Hiroshi Tsumura

Keyword(s):

Racial Differences ◽

Ethnic Differences ◽

Three Dimensional ◽

Knee Joints ◽

Bone Morphology ◽

Japanese Men ◽

Dimensional Measurements ◽

Total Knee ◽

Caucasian Women ◽

The Individual

Abstract Background: To examine racial and sex-related differences in bone morphology and to determine whether it is necessary to take sex-related and ethnic differences into account in designing artificial knee joints.Methods: Hundred Japanese women normal knees, 88 Japanese men normal knees, and 18 Caucasian women normal knees were examined. Knee joints were measured to enable selection and design of artificial knee joints based on assumed bone resection face dimensions in TKA. Results: The dimensional measurements were performed by reading the three-dimensional CT based bone model. F-MAP/F-ML and F-LAP/F-ML relative to F-ML dimensions and T-MAP/T-ML and T-LAP/T-ML relative to T-ML dimensions were determined in both sexes. Results: In both sexes and in both the femur and tibia, the value increased with decreasing size. Therefore, the width narrowed with decreasing size. It was considered that the width may be narrower in women than in men because women have smaller bone sizes than men. The matching ratio was considered to improve as the aspect ratio is adjusted according to the size when an artificial joint is designed. There were no significant differences in the measured sagittal flexion angle between the Japanese and Caucasian women. Conclusion: The individual differences were greater than the racial differences; therefore, we consider that there is no significant need to change the shape of the artificial knee joint according to racial differences in bone morphology.

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Fusing Stereo Camera and Low-Cost Inertial Measurement Unit for Autonomous Navigation in a Tightly-Coupled Approach

Journal of Navigation ◽

10.1017/s0373463314000848 ◽

2014 ◽

Vol 68 (3) ◽

pp. 434-452 ◽

Cited By ~ 10

Author(s):

Zhiwen Xian ◽

Xiaoping Hu ◽

Junxiang Lian

Keyword(s):

Autonomous Navigation ◽

Inertial Sensors ◽

Inertial Sensor ◽

Low Cost ◽

Three Dimensional ◽

Fast Response ◽

Location Estimation ◽

Measurement Unit ◽

Navigation Systems ◽

Stereo Camera

Exact motion estimation is a major task in autonomous navigation. The integration of Inertial Navigation Systems (INS) and the Global Positioning System (GPS) can provide accurate location estimation, but cannot be used in a GPS denied environment. In this paper, we present a tight approach to integrate a stereo camera and low-cost inertial sensor. This approach takes advantage of the inertial sensor's fast response and visual sensor's slow drift. In contrast to previous approaches, features both near and far from the camera are simultaneously taken into consideration in the visual-inertial approach. The near features are parameterised in three dimensional (3D) Cartesian points which provide range and heading information, whereas the far features are initialised in Inverse Depth (ID) points which provide bearing information. In addition, the inertial sensor biases and a stationary alignment are taken into account. The algorithm employs an Iterative Extended Kalman Filter (IEKF) to estimate the motion of the system, the biases of the inertial sensors and the tracked features over time. An outdoor experiment is presented to validate the proposed algorithm and its accuracy.

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Evaluation of Inertial Sensor-Based Pre-Impact Fall Detection Algorithms Using Public Dataset

Sensors ◽

10.3390/s19040774 ◽

2019 ◽

Vol 19 (4) ◽

pp. 774 ◽

Cited By ~ 5

Author(s):

Soonjae Ahn ◽

Jongman Kim ◽

Bummo Koo ◽

Youngho Kim

Keyword(s):

Angular Velocity ◽

Inertial Sensor ◽

Fall Detection ◽

Measurement Unit ◽

Elderly Subjects ◽

Blind Test ◽

Detection Algorithms ◽

Trunk Inclination ◽

Custom Made ◽

Public Dataset

In this study, pre-impact fall detection algorithms were developed based on data gathered by a custom-made inertial measurement unit (IMU). Four types of simulated falls were performed by 40 healthy subjects (age: 23.4 ± 4.4 years). The IMU recorded acceleration and angular velocity during all activities. Acceleration, angular velocity, and trunk inclination thresholds were set to 0.9 g, 47.3°/s, and 24.7°, respectively, for a pre-impact fall detection algorithm using vertical angles (VA algorithm); and 0.9 g, 47.3°/s, and 0.19, respectively, for an algorithm using the triangle feature (TF algorithm). The algorithms were validated by the results of a blind test using four types of simulated falls and six types of activities of daily living (ADL). VA and TF algorithms resulted in lead times of 401 ± 46.9 ms and 427 ± 45.9 ms, respectively. Both algorithms were able to detect falls with 100% accuracy. The performance of the algorithms was evaluated using a public dataset. Both algorithms detected every fall in the SisFall dataset with 100% sensitivity). The VA algorithm had a specificity of 78.3%, and TF algorithm had a specificity of 83.9%. The algorithms had higher specificity when interpreting data from elderly subjects. This study showed that algorithms using angles could more accurately detect falls. Public datasets are needed to improve the accuracy of the algorithms.

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Estimation of 3D Body Center of Mass Acceleration and Instantaneous Velocity from a Wearable Inertial Sensor Network in Transfemoral Amputee Gait: A Case Study

Sensors ◽

10.3390/s21093129 ◽

2021 ◽

Vol 21 (9) ◽

pp. 3129

Author(s):

Emeline Simonetti ◽

Elena Bergamini ◽

Giuseppe Vannozzi ◽

Joseph Bascou ◽

Hélène Pillet

Keyword(s):

Sensor Network ◽

Inertial Sensor ◽

Center Of Mass ◽

Vertical Component ◽

The Body ◽

Estimation Accuracy ◽

Measurement Unit ◽

Transfemoral Amputee ◽

Body Center ◽

The Impact

The analysis of the body center of mass (BCoM) 3D kinematics provides insights on crucial aspects of locomotion, especially in populations with gait impairment such as people with amputation. In this paper, a wearable framework based on the use of different magneto-inertial measurement unit (MIMU) networks is proposed to obtain both BCoM acceleration and velocity. The proposed framework was validated as a proof of concept in one transfemoral amputee against data from force plates (acceleration) and an optoelectronic system (acceleration and velocity). The impact in terms of estimation accuracy when using a sensor network rather than a single MIMU at trunk level was also investigated. The estimated velocity and acceleration reached a strong agreement (ρ > 0.89) and good accuracy compared to reference data (normalized root mean square error (NRMSE) < 13.7%) in the anteroposterior and vertical directions when using three MIMUs on the trunk and both shanks and in all three directions when adding MIMUs on both thighs (ρ > 0.89, NRMSE ≤ 14.0% in the mediolateral direction). Conversely, only the vertical component of the BCoM kinematics was accurately captured when considering a single MIMU. These results suggest that inertial sensor networks may represent a valid alternative to laboratory-based instruments for 3D BCoM kinematics quantification in lower-limb amputees.

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Semi-automated methods for 3-D reconstruction of macromolecular complexes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136581 ◽

1995 ◽

Vol 53 ◽

pp. 42-43

Author(s):

B. Carragher ◽

M. Whittaker

Keyword(s):

Three Dimensional ◽

Time Saving ◽

Macromolecular Complexes ◽

Symmetry Properties ◽

Dimensional Reconstruction ◽

Experienced Operator ◽

Projection Images ◽

The Individual ◽

Natural Symmetry

Techniques for three-dimensional reconstruction of macromolecular complexes from electron micrographs have been successfully used for many years. These include methods which take advantage of the natural symmetry properties of the structure (for example helical or icosahedral) as well as those that use single axis or other tilting geometries to reconstruct from a set of projection images. These techniques have traditionally relied on a very experienced operator to manually perform the often numerous and time consuming steps required to obtain the final reconstruction. While the guidance and oversight of an experienced and critical operator will always be an essential component of these techniques, recent advances in computer technology, microprocessor controlled microscopes and the availability of high quality CCD cameras have provided the means to automate many of the individual steps.During the acquisition of data automation provides benefits not only in terms of convenience and time saving but also in circumstances where manual procedures limit the quality of the final reconstruction.

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Construction of citizenship in hospitalized children, Peru

Journal of Global Education Sciences ◽

10.32829/ges.v1i1.73 ◽

2019 ◽

Vol 1 (1) ◽

pp. 31

Author(s):

Fernando Ledesma Perez ◽

Maria Caycho Avalos ◽

Juana Cruz Montero ◽

Andrea Ayala Sandoval

Keyword(s):

Structured Interview ◽

Health Condition ◽

Qualitative Approach ◽

Fundamental Rights ◽

Hospitalized Children ◽

Health Institute ◽

Interview Guide ◽

Communication Interaction ◽

The Individual

Citizenship is the exercise of the fundamental rights of people in spaces of participation, opinion and commitments, which can not be violated by any health condition in which the individual is. This research aims to interpret the process of construction of citizenship in hospitalized children, was developed through the qualitative approach, ethnomethodological method, synchronous design, with a sample of three students hospitalized in a health institute specializing in childhood, was used Observation technique and a semi-structured interview guide were obtained as results that hospitalized children carry out their citizenship construction in an incipient way, through the communication interaction they make with other people in the environment where they grow up.

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Phonetic iconicity in the evaluative morphology of a sample of Indo-European, Niger-Congo and Austronesian languages

WORD Structure ◽

10.3366/word.2010.0003 ◽

2010 ◽

Vol 3 (2) ◽

pp. 156-180 ◽

Cited By ~ 3

Author(s):

Renáta Gregová ◽

Lívia Körtvélyessy ◽

Július Zimmermann

Keyword(s):

Three Dimensional ◽

Sound Symbolism ◽

Three Dimensional Model ◽

Austronesian Languages ◽

Place Of Articulation ◽

European Languages ◽

Phonetic Symbolism ◽

The Individual ◽

Core Vocabulary

Universals Archive (Universal #1926) indicates a universal tendency for sound symbolism in reference to the expression of diminutives and augmentatives. The research ( Štekauer et al. 2009 ) carried out on European languages has not proved the tendency at all. Therefore, our research was extended to cover three language families – Indo-European, Niger-Congo and Austronesian. A three-step analysis examining different aspects of phonetic symbolism was carried out on a core vocabulary of 35 lexical items. A research sample was selected out of 60 languages. The evaluative markers were analyzed according to both phonetic classification of vowels and consonants and Ultan's and Niewenhuis' conclusions on the dominance of palatal and post-alveolar consonants in diminutive markers. Finally, the data obtained in our sample languages was evaluated by means of a three-dimensional model illustrating the place of articulation of the individual segments.

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Improvement of Gait Dysfunction after Applying a Hinged Ankle–Foot Orthosis in a Hemiplegic Cerebral Palsy Patient with Disrupted Medial Lemniscus: A Case Report

Children ◽

10.3390/children8020081 ◽

2021 ◽

Vol 8 (2) ◽

pp. 81

Author(s):

Su Min Son ◽

Min Cheol Chang

Keyword(s):

Knee Flexion ◽

Diffusion Tensor ◽

Therapeutic Option ◽

Gait Pattern ◽

Ankle Dorsiflexion ◽

Medial Lemniscus ◽

Abnormal Gait ◽

Hemiplegic Cerebral Palsy ◽

Genu Recurvatum ◽

Magnetic Resonance Imaging Mri

We describe the successful application of hinged ankle−foot orthoses (AFOs) in a cerebral palsied (CP) patient with gait instability due to a disrupted medial lemniscus (ML). The patient was a 27-month-old male CP child with gait instability who presented with reduced knee flexion and ankle dorsiflexion, with severe genu recurvatum on his right lower extremity during gait. The patient had no motor weakness or spasticity. Conventional magnetic resonance imaging (MRI) revealed no definite abnormal lesion. However, diffusion tensor tractography (DTT) showed disruption of the left ML, consistent with right hemiplegic symptoms. The integrity of the major motor-related neural tracts, including the corticospinal and corticoreticulospinal tracts, was preserved. We considered that the patient’s abnormal gait pattern was related to the disrupted ML state. We applied hinged AFOs, which immediately resulted in a significantly stabilized gait. The angles of knee flexion and ankle dorsiflexion increased. Our findings indicate that the application of hinged AFOs could be a useful therapeutic option for CP patients with gait instability related to ML disruption. In addition, we showed that DTT is a useful tool for identifying the causative brain pathology in CP patients, especially when conventional brain MRIs show no specific lesion.

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A novel clinical applicable bed-side tool for assessing conditioning pain modulation: proof-of-concept

Scandinavian Journal of Pain ◽

10.1515/sjpain-2020-0033 ◽

2020 ◽

Vol 20 (4) ◽

pp. 801-807

Author(s):

Lars Arendt-Nielsen ◽

Jesper Bie Larsen ◽

Stine Rasmussen ◽

Malene Krogh ◽

Laura Borg ◽

...

Keyword(s):

Pain Modulation ◽

Clinical Settings ◽

Proof Of Concept ◽

Finger Nail ◽

Tonic Stimulus ◽

Pressure Pain Thresholds ◽

Custom Made ◽

The Individual ◽

Descending Pain Modulation ◽

Finger Pressure

AbstractBackground and aimsIn recent years, focus on assessing descending pain modulation or conditioning pain modulation (CPM) has emerged in patients with chronic pain. This requires reliable and simple to use bed-side tools to be applied in the clinic. The aim of the present pilot study was to develop and provide proof-of-concept of a simple clinically applicable bed-side tool for assessing CPM.MethodsA group of 26 healthy volunteers participated in the experiment. Pressure pain thresholds (PPT) were assessed as test stimuli from the lower leg before, during and 5 min after delivering the conditioning tonic painful pressure stimulation. The tonic stimulus was delivered for 2 min by a custom-made spring-loaded finger pressure device applying a fixed pressure (2.2 kg) to the index finger nail. The pain intensity provoked by the tonic stimulus was continuously recorded on a 0–10 cm Visual Analog Scale (VAS).ResultsThe median tonic pain stimulus intensity was 6.7 cm (interquartile range: 4.6–8.4 cm) on the 10 cm VAS. The mean PPT increased significantly (P = 0.034) by 55 ± 126 kPa from 518 ± 173 kPa before to 573 ± 228 kPa during conditioning stimulation. When analyzing the individual CPM responses (increases in PPT), a distribution of positive and negative CPM responders was observed with 69% of the individuals classified as positive CPM responders (increased PPTs = anti-nociceptive) and the rest as negative CPM responders (no or decreased PPTs = Pro-nociceptive). This particular responder distribution explains the large variation in the averaged CPM responses observed in many CPM studies. The strongest positive CPM response was an increase of 418 kPa and the strongest negative CPM response was a decrease of 140 kPa.ConclusionsThe present newly developed conditioning pain stimulator provides a simple, applicable tool for routine CPM assessment in clinical practice. Further, reporting averaged CPM effects should be replaced by categorizing volunteers/patients into anti-nociceptive and pro-nociceptive CPM groups.ImplicationsThe finger pressure device provided moderate-to-high pain intensities and was useful for inducing conditioning stimuli. Therefore, the finger pressure device could be a useful bed-side method for measuring CPM in clinical settings with limited time available. Future bed-side studies involving patient populations are warranted to determine the usefulness of the method.

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