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Hyunwoo Lee, Mincheol Whang
Cardiac activity has been monitored continuously in daily life by virtue of advanced medical instruments with microelectromechanical system (MEMS) technology. Seismocardiography (SCG) has been considered to be free from the burden of measurement for cardiac activity, but it has been limited in its application in daily life. The most important issues regarding SCG are to overcome the limitations of motion artifacts due to the sensitivity of motion sensor. Although novel adaptive filters for noise cancellation have been developed, they depend on the researcher’s subjective decision...
May 1, 2018: Sensors
Chunxi Zhang, Shaobo Zhang, Xiong Pan, Jing Jin
Electrical crosstalk in an interferometric fiber-optic gyroscope (IFOG) is regarded as the most significant factor influencing dead bands. Here, we present a six-state modulation (SSM) technique to reduce crosstalk. Compared to conventional four-state modulation (FSM) or square-wave modulation (SWM), the SSM reduces the correlation between modulation voltage and demodulation reference by separating their fundamental frequencies, and thus reduces the bias error induced by crosstalk. The measured dead band of a 1500-m IFOG is approximately 0...
April 16, 2018: Optics Express
Han Byul Kim, Hong Ji Lee, Woong Woo Lee, Sang Kyong Kim, Hyo Seon Jeon, Hye Young Park, Chae Won Shin, Won Jin Yi, Beomseok Jeon, Kwang S Park
BACKGROUND: Freezing of gait (FOG) is a commonly observed motor symptom for patients with Parkinson's disease (PD). The symptoms of FOG include reduced step lengths or motor blocks, even with an evident intention of walking. FOG should be monitored carefully because it not only lowers the patient's quality of life, but also significantly increases the risk of injury. INTRODUCTION: In previous studies, patients had to wear several sensors on the body and another computing device was needed to run the FOG detection algorithm...
April 30, 2018: Telemedicine Journal and E-health: the Official Journal of the American Telemedicine Association
Florian Lipsmeier, Kirsten I Taylor, Timothy Kilchenmann, Detlef Wolf, Alf Scotland, Jens Schjodt-Eriksen, Wei-Yi Cheng, Ignacio Fernandez-Garcia, Juliane Siebourg-Polster, Liping Jin, Jay Soto, Lynne Verselis, Frank Boess, Martin Koller, Michael Grundman, Andreas U Monsch, Ronald B Postuma, Anirvan Ghosh, Thomas Kremer, Christian Czech, Christian Gossens, Michael Lindemann
BACKGROUND: Ubiquitous digital technologies such as smartphone sensors promise to fundamentally change biomedical research and treatment monitoring in neurological diseases such as PD, creating a new domain of digital biomarkers. OBJECTIVES: The present study assessed the feasibility, reliability, and validity of smartphone-based digital biomarkers of PD in a clinical trial setting. METHODS: During a 6-month, phase 1b clinical trial with 44 Parkinson participants, and an independent, 45-day study in 35 age-matched healthy controls, participants completed six daily motor active tests (sustained phonation, rest tremor, postural tremor, finger-tapping, balance, and gait), then carried the smartphone during the day (passive monitoring), enabling assessment of, for example, time spent walking and sit-to-stand transitions by gyroscopic and accelerometer data...
April 27, 2018: Movement Disorders: Official Journal of the Movement Disorder Society
Carol S Bruggers, Sabrina Baranowski, Mathew Beseris, Rachel Leonard, Derek Long, Elizabeth Schulte, Ashton Shorter, Rowan Stigner, Clinton C Mason, Alisa Bedrov, Ian Pascual, Grzegorz Bulaj
Background: Medical advances continue to improve morbidity and mortality of serious pediatric diseases, including cancer, driving research addressing diminished physical and psychological quality of life in children with these chronic conditions. Empowerment enhances resilience and positively influences health, disease, and therapy understanding. We describe the development and usability assessment of a prototype Empower Stars! mobile video game grounded in behavioral and exercise theories with the purpose of coupling physical exercise with empowerment over disease in children with cancer...
2018: Frontiers in Pediatrics
Raisa Z Freidlin, Amisha D Dave, Benjamin G Espey, Sean T Stanley, Marcial A Garmendia, Randall Pursley, Johnathon P Ehsani, Bruce G Simons-Morton, Thomas J Pohida
BACKGROUND: Naturalistic driving studies, designed to objectively assess driving behavior and outcomes, are conducted by equipping vehicles with dedicated instrumentation (eg, accelerometers, gyroscopes, Global Positioning System, and cameras) that provide continuous recording of acceleration, location, videos, and still images for eventual retrieval and analyses. However, this research is limited by several factors: the cost of equipment installation; management and storage of the large amounts of data collected; and data reduction, coding, and analyses...
April 19, 2018: JMIR MHealth and UHealth
Luis A Sanchez-Perez, Luis P Sanchez-Fernandez, Adnan Shaout, Juan M Martinez-Hernandez, Maria J Alvarez-Noriega
BACKGROUND: Currently the most consistent, widely accepted and detailed instrument to rate Parkinson's disease (PD) is the Movement Disorder Society sponsored Unified Parkinson Disease Rating Scale (MDS-UPDRS). However, the motor examination is based upon subjective human interpretation trying to capture a snapshot of PD status. Wearable sensors and machine learning have been broadly used to analyze PD motor disorder, but still most ratings and examinations lay outside MDS-UPDRS standards...
June 2018: International Journal of Medical Informatics
Zhibo Ma, Yinan Wang, Qiang Shen, Han Zhang, Xuetao Guo
MEMS fabrication that is based on the silicon-on-glass (SOG) process requires many steps, including patterning, anodic bonding, deep reactive ion etching (DRIE), and chemical mechanical polishing (CMP). The effects of the process parameters of CMP and DRIE are investigated in this study. The process parameters of CMP, such as abrasive size, load pressure, and pH value of SF1 solution are examined to optimize the total thickness variation in the structure and the surface quality. The ratio of etching and passivation cycle time and the process pressure are also adjusted to achieve satisfactory performance during DRIE...
April 17, 2018: Sensors
Hasan Tahir, Ruhma Tahir, Klaus McDonald-Maier
Miniaturization of computer hardware and the demand for network capable devices has resulted in the emergence of a new class of technology called wearable computing. Wearable devices have many purposes like lifestyle support, health monitoring, fitness monitoring, entertainment, industrial uses, and gaming. Wearable devices are hurriedly being marketed in an attempt to capture an emerging market. Owing to this, some devices do not adequately address the need for security. To enable virtualization and connectivity wearable devices sense and transmit data, therefore it is essential that the device, its data and the user are protected...
2018: PloS One
Jiaying Du, Christer Gerdtman, Maria Lindén
Motion sensors such as MEMS gyroscopes and accelerometers are characterized by a small size, light weight, high sensitivity, and low cost. They are used in an increasing number of applications. However, they are easily influenced by environmental effects such as temperature change, shock, and vibration. Thus, signal processing is essential for minimizing errors and improving signal quality and system stability. The aim of this work is to investigate and present a systematic review of different signal error reduction algorithms that are used for MEMS gyroscope-based motion analysis systems for human motion analysis or have the potential to be used in this area...
April 6, 2018: Sensors
Ernesto de la Rubia, Antonio Diaz-Estrella, Arcadio Reyes-Lecuona, Alyson Langley, Michael Brown, Sarah Sharples
Inertial sensors offer the potential for integration into wireless virtual reality systems that allow the users to walk freely through virtual environments. However, owing to drift errors, inertial sensors cannot accurately estimate head and body orientations in the long run, and when walking indoors, this error cannot be corrected by magnetometers, due to the magnetic field distortion created by ferromagnetic materials present in buildings. This paper proposes a technique, called EHBD (Equalization of Head and Body Directions), to address this problem using two head- and shoulder-located magnetometers...
2018: PloS One
Maolin Liu, Huaiyu Li, Yuan Wang, Fei Li, Xiuwan Chen
Accelerometers, gyroscopes and magnetometers in smartphones are often used to recognize human motions. Since it is difficult to distinguish between vertical motions and horizontal motions in the data provided by these built-in sensors, the vertical motion recognition accuracy is relatively low. The emergence of a built-in barometer in smartphones improves the accuracy of motion recognition in the vertical direction. However, there is a lack of quantitative analysis and modelling of the barometer signals, which is the basis of barometer's application to motion recognition, and a problem of imbalanced data also exists...
April 1, 2018: Sensors
Samantha Sze-Yee Lee, Alex A Black, Joanne M Wood
PURPOSE: To assess the link between visual scanning behaviour and closed-road driving performance in older drivers with glaucomatous visual impairment. METHODS: Participants included 13 older drivers with glaucoma (mean age=72.0±6.7▒y; average better-eye mean deviation [MD])=-2.9±2.1▒dB, average worse-eye MD=-12.5±7.1▒dB) and ten visually-normal controls (mean age=70.6±7.4▒y). Visual acuity, contrast sensitivity, visual fields, useful field-of-view (UFoV), and motion sensitivity were assessed...
April 2, 2018: Journal of Glaucoma
Kun Liu, Jianchao Yan, Yong Liu, Ming Ye
An original approach for noninvasive estimation of lower limb joint moments for analysis of STS rehabilitation training with only inertial measurement units was presented based on a piecewise three-segment STS biomechanical model and a double-sensor difference based algorithm. Joint kinematic and kinetic analysis using a customized wearable sensor system composed of accelerometers and gyroscopes were presented and evaluated compared with a referenced camera system by five healthy subjects and five patients in rehabilitation...
2018: Journal of Healthcare Engineering
Jacob A Garlant, Kaitlyn R Ammann, Marvin J Slepian
Digital tracking of human motion offers the potential to monitor a wide range of activities detecting normal versus abnormal performance of tasks. We examined the ability of a wearable, conformal sensor system, fabricated from stretchable electronics with contained accelerometers and gyroscopes, to specifically detect, monitor, and define motion signals and "signatures," associated with tasks of daily living activities. The sensor system was affixed to the dominant hand of healthy volunteers (n = 4) who then completed four tasks...
March 28, 2018: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
Kai Bötzel, Alberto Olivares, João Paulo Cunha, Juan Manuel Górriz Sáez, Robin Weiss, Annika Plate
Measuring human gait is important in medicine to obtain outcome parameter for therapy, for instance in Parkinson's disease. Recently, small inertial sensors became available which allow for the registration of limb-position outside of the limited space of gait laboratories. The computation of gait parameters based on such recordings has been the subject of many scientific papers. We want to add to this knowledge by presenting a 4-segment leg model which is based on inverse kinematic and Kalman filtering of data from inertial sensors...
March 15, 2018: Journal of Biomechanics
Yang Gao, Libin Huang, Xukai Ding, Hongsheng Li
This paper presents the design and implementation of a dual-mass MEMS gyroscope with high shock resistance by improving the in-phase frequency of the gyroscope and by using a two-stage elastic stopper mechanism and proposes a Simulink shock model of the gyroscope equipped with the two-stage stopper mechanism, which is a very efficient method to evaluate the shock resistance of the gyroscope. The structural design takes into account both the mechanical sensitivity and the shock resistance. The design of the primary structure and the analysis of the stopper mechanism are first introduced...
March 30, 2018: Sensors
Yan Su, Xin Tong, Nan Liu, Guowei Han, Chaowei Si, Jin Ning, Zhaofeng Li, Fuhua Yang
With an aim to reduce the cost of prototype development, this paper establishes a PSPICE hybrid model for the simulation of capacitive microelectromechanical systems (MEMS) gyroscopes. This is achieved by modeling gyroscopes in different modules, then connecting them in accordance with the corresponding principle diagram. Systematic simulations of this model are implemented along with a consideration of details of MEMS gyroscopes, including a capacitance model without approximation, mechanical thermal noise, and the effect of ambient temperature...
March 28, 2018: Sensors
Dang-Nhac Lu, Duc-Nhan Nguyen, Thi-Hau Nguyen, Ha-Nam Nguyen
In this paper, we present a flexible combined system, namely the Vehicle mode-driving Activity Detection System (VADS), that is capable of detecting either the current vehicle mode or the current driving activity of travelers. Our proposed system is designed to be lightweight in computation and very fast in response to the changes of travelers' vehicle modes or driving events. The vehicle mode detection module is responsible for recognizing both motorized vehicles, such as cars, buses, and motorbikes, and non-motorized ones, for instance, walking, and bikes...
March 29, 2018: Sensors
Elizabeth B Torres, Joe Vero, Richa Rai
Wearable biosensors, such as those embedded in smart phones, can provide data to assess neuro-motor control in mobile settings, at homes, schools, workplaces and clinics. However, because most machine learning algorithms currently used to analyze such data require several steps that depend on human heuristics, the analyses become computationally expensive and rather subjective. Further, there is no standardized scale or set of tasks amenable to take advantage of such technology in ways that permit broad dissemination and reproducibility of results...
March 29, 2018: Sensors
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