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1.
Med Biol Eng Comput ; 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33269461

RESUMO

Electric contact currents (CC) can cause muscle contractions, burns, or ventricular fibrillation which may result in life-threatening situations. In vivo studies with CC are rare due to potentially hazardous effects for participants. Cadaver studies are limited to the range of tissue's electrical properties and the utilized probes' size, relative position, and sensitivity. Thus, the general safety standards for protection against CC depend on a limited scientific basis. The aim of this study was therefore to develop an extendable and adaptable validated numerical body model for computational CC dosimetry for frequencies between DC and 1 MHz. Applying the developed model for calculations of the IEC heart current factors (HCF) revealed that in the case of transversal CCs, HCFs are frequency dependent, while for longitudinal CCs, the HCFs seem to be unaffected by frequency. HCFs for current paths from chest or back to hand appear to be underestimated by the International Electrotechnical Commission (IEC 60479-1). Unlike the HCFs provided in IEC 60479-1 for longitudinal current paths, our work predicts the HCFs equal 1.0, possibly due to a previously unappreciated current flow through the blood vessels. However, our results must be investigated by further research in order to make a definitive statement. Contact currents of frequencies from DC up to 100 kHz were conducted through the numerical body model Duke by seven contact electrodes on longitudinal and transversal paths. The resulting induced electric field and current enable the evaluation of the body impedance and the heart current factors for each frequency and current path.

2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5016-5020, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019113

RESUMO

INTRODUCTION: Our primary goal was to evaluate the performance of a new high-efficiency electric fence energizer unit using resistive load changes. Our secondary goal was to test for compliance with the classical energy limits and the newer charge-based limits for output. METHODS: We tested 4 units of the Nemtek Druid energizer with 2 channels each. We used a wide load-resistance range to cover the worst-case scenario of a barefoot child making a chest contact (400 Ω) up to an adult merely touching the fence (2 kΩ). RESULTS: The energy output was quite consistent between the 8 sources. Even at the lowest resistance, 400 Ω, the outputs were well below the IEC 60335-2-76 limit of 5 J/pulse. The charge delivered was also quite consistent. Even at the lowest resistance, 400 Ω, the outputs (679 ± 23 µC) were well below the proposed limits of 4 mC for short pulses. CONCLUSIONS: The high-efficiency electric fence energizers satisfied all relevant safety limits. Charge, energy, voltage, and current outputs were consistent between channels and units.


Assuntos
Eletricidade , Adulto , Criança , Frequência Cardíaca , Humanos , Fenômenos Físicos
3.
IEEE Rev Biomed Eng ; 13: 325-339, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30951478

RESUMO

In this review, we present current state-of-the-art developments and challenges in the areas of thermal therapy, ultrasound tomography, image-guided therapies, ocular drug delivery, and robotic devices in neurorehabilitation. Additionally, intellectual property and regulatory aspects pertaining to therapeutic systems and technologies are addressed.


Assuntos
Engenharia Biomédica , Diagnóstico por Imagem , Terapia Assistida por Computador , Humanos , Propriedade Intelectual , Nanomedicina , Reabilitação Neurológica
4.
J Trauma Acute Care Surg ; 87(2): 483-490, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31045725

RESUMO

BACKGROUND: Electric shocks are common, and victims report difficulty in finding practitioners with knowledge of the injury. Medical Practitioners, especially in private practice, report lack of knowledge of the injury and lack of expertise in assessing and treating the injury. The authors are often requested to suggest investigation protocols, assessment protocols, and treatment protocols, and to provide educational information. METHODS: The international body establishing electrical standards on the effects of current on the body (International Electrotechnical Commission, Maintenance Team 4 (MT4) of Technical Committee 64 (TC64)) have established protocols for the factors which require documentation and reporting of the injury. This article provides a narrative approach to using these protocols in accord with the standards (IEC 60479). The level of evidence is Level III (US/Canada classification). TYPE: This article collects together and collates physical and medical aspects of investigating electric shocks, and summarizes those of importance, and which are potentially forgotten. The thoroughness of initial assessment is emphasized. SUBSTANCE: Summaries are set out to guide first attenders and emergency medical personnel as to findings and observations which must be recorded for later comprehensive medicolegal reporting and which are often overlooked. CONCLUSION: Wider teaching in the nature of electric shocks will enhance assessment of victims and thorough recording of pertinent information and thus will enhance later medicolegal reporting. Many such factors are initially overlooked and lead to inadequate reporting for forensic purposes.


Assuntos
Documentação/normas , Traumatismos por Eletricidade/etiologia , Serviços Médicos de Emergência/normas , Segurança/normas , Protocolos Clínicos/normas , Documentação/métodos , Traumatismos por Eletricidade/diagnóstico , Traumatismos por Eletricidade/prevenção & controle , Traumatismos por Eletricidade/terapia , Humanos
5.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 1769-1775, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31946240

RESUMO

In most cases, the diagnosis of an electrical injury or electrocution is straightforward. However, there is a necessity for much closer analysis in many cases. There exist sophisticated electrical safety standards that predict outcomes for shocks of various currents applied to different parts of the body. Unfortunately, the actual current is almost never known in an accident investigation. A common source of errors is the assumption that the source (including the return) has zero impedance. Another surprisingly common problem is the erroneous assumption that the body current is equal to the source current capability. METHODS: We used the following methodology for analyzing such cases: (1) Determine body pathway, (2) Estimate body pathway impedance, (3) Determine source voltage, (4) Determine source impedance, (5) Calculate delivered current using total pathway impedance, and (6) Ignore available current as it is largely confounding in most cases. RESULTS: We analyzed 6 difficult cases using the above methodology. This includes 2 subtle situations involving pairs of matched case-control subjects where a subject was electrocuted while his work partner was not. CONCLUSIONS: Careful calculations of the amplitude and duration of the shock is required for understanding the limits and potential causation of such electrical injury. This requires the determination of both the source and body pathway impedance. Available current is usually irrelevant and overemphasized.


Assuntos
Impedância Elétrica , Traumatismos por Eletricidade , Interpretação Estatística de Dados , Traumatismos por Eletricidade/diagnóstico , Humanos
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 1788-1794, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31946244

RESUMO

Electrical safety limits for unidirectional pulses with short durations are increasingly important due to the proliferation of electric-car and factory energy storage systems with potentially dangerous voltages. Electrocution by a short-duration direct-current pulse is not understood as well as that by alternating current and the data are limited. The primary international guidance comes from IEC 60479-2 section 11. METHODS: We have analyzed the dosimetry for short pulse safety limits based on a fuller understanding of the scientific principles involved and human data. Implantable defibrillators have been tested by externally delivering short-duration pulses giving us human data which we analyze for this paper. RESULTS: The present IEC current limit (60479-2:11) for short pulse durations is based on an exponent of -0.68 in the equation I = d-0.68, (d being pulse width), while the correct exponent should be -1.0 given the constant charge for the VF threshold of short pulses. We also propose a baseline charge value based on the human data. CONCLUSIONS: Charge-based VF thresholds give the correct dosimetry for short-duration pulses. Results from this paper should be considered in support of revising the IEC 60479-2 standard section 11.


Assuntos
Desfibriladores Implantáveis , Fibrilação Ventricular , Arritmias Cardíacas , Traumatismos por Eletricidade , Eletricidade , Humanos , Modelos Estatísticos , Radiometria
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 6149-6154, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31947247

RESUMO

The G.L.O.V.E (Generated Low Output Voltage Emitter) is a tool for law-enforcement professionals operating in a wider band of the force continuum than other intermediate weapons. The goal of this paper was to analyze the G.L.O.V.E electrical output and to compare it to safety and efficacy requirements of relevant international standards. Methods - Four G.L.O.V.Es were tested. Measurements on fresh, skinned animal tissue established a G.L.O.V.E operational impedance range of 140 - 300 Ω. Their voltage, current, charge, pulse duration and rate were measured when applied to loads from 140 to 330 Ω. Measurements were also taken with two G.L.O.V.E devices simultaneously applied to a resistive network which simulated a hand-hand, or shoulder-shoulder, currentflow path. Such path may involve cardiac risk. The measurement results were compared to relevant safety and efficacy requirements of following standards: UL 69, IEC 60335-7-26, IEC 60479-1 and -2, and ANSI/CPLSO-17. Results - Within its operational load range, the G.L.O.V.E device delivers maximum voltages in the range of 210 - 320 V, maximum currents of 0.9 - 1.5 A, charge levels of 84 - 125 µC with pulse durations between 105 - 115 µs, with repetition rates of 29.7 - 30.8 pps and duty cycles of 0.32 - 0.35%. These parameters were all within relevant ranges required by UL 69, IEC 60335-7-26, IEC 60479-1 and -2, and ANSI/CPLSO-17. Conclusion - Based on our measurement data, the G.L.O.V.E device is in compliance with relevant requirements for safety and efficacy stated by standards such as UL 69, IEC 60335-7-26, IEC 60479-1 and -2, and ANSI/CPLSO-17.


Assuntos
Eletricidade , Coração , Aplicação da Lei , Padrões de Referência
8.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 2234-2239, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30440850

RESUMO

INTRODUCTION: Human electronic control with the Conducted Electrical Weapon (CEW) has gained widespread acceptance as the preferred law enforcement force option technology due to its dramatic injury and fatal shooting reduction. However, with bulky or baggy clothing, a CEW probe may fail to make direct skin contact and thus arcing is critical to complete the circuit. The goal of the study was to evaluate the ability of modern CEWs to deliver their pulse charges across typical required arcing distances. METHODS: Popular TASER® CEW models X26E (openloop output), and the X2 and X26P (with closed-loop outputs) were activated using a cartridge connected to a custom polymer air-gap fixture. For each model 5 units were tested. The raw and normalized charge delivery were evaluated according to ANSI-CPLSO-17. RESULTS: All 5 units of each model satisfied ANSICPLSO-17 even at maximum arcing length. The X26P CEW had the greatest arcing gap capability. CONCLUSIONS: The stabilized closed-loop charge output feedback of modern electrical weapons (X2 and X26P CEWs) provides a significantly improved output consistency under arcing conditions. With arc lengths of 10-20 mm per probe, the X2 CEW normalized output charge exceeds that of some units of the older higher output X26E CEW model.


Assuntos
Armas , Lesões por Armas de Eletrochoque , Eletricidade , Eletrochoque , Frequência Cardíaca , Humanos , Aplicação da Lei , Pele
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 2170-2176, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29060327

RESUMO

Introduction-We have previously published on the ventricular fibrillation (VF) risk with TASER® X26 conducted electrical weapon (CEW). Our risk model accounted for realistic body mass index distributions, modeled the effects of partial or oblique dart penetration, and used epidemiological CEW statistics. As new CEWs have become available to law enforcement, their cardiac safety profile was not quantified. Therefore, we applied our VF probability model to evaluate their cardiac risk. Methods and Results-An eXperimental Rotating-Field (XRF) waveform CEW and the X2 CEW are new 2-shot electrical weapon models designed to target a precise amount of delivered charge per pulse, 64 µC and 62 µC, respectively. They can deploy 1 or 2 probe pairs, delivered by 2 separate cartridges. New Smart Probes (SP), which carry 11.5 mm long CEW darts, can be used with XRF and X2 CEWs. Finite element modeling (FEM) was used to approximate the current and charge densities produced by XRF and X2 CEWs in tissues located in the vicinity of darts, including accounting for the effects of fat, anisotropic skeletal muscles, sternum, ribs, and lungs. Using our previous cardiac risk probabilistic model, the new XRF and X2 CEWs operated with 11.5 mm SPs, had an estimated overall theoretical VF risk of less than 1 in 1 300 000 and 1 in 1 490 000 cases, respectively. We also found that the XRF and X2 CEWs had increased cardiac safety margins with respect to those previously reported for the X26 CEWs when all three CEW models were operated with 9 mm CEW darts. Lastly, the cardiac risk of these new CEWs (<; 0.76 ppm) was found to be much lower than reported levels of CEW non-cardiac fatal injuries (e.g. falls and burns, > 7.2 ppm). Conclusions-While not risk-free, the new TASER XRF and X2 CEWs offer increased cardiac safety margins and extremely low cardiac risk profiles.


Assuntos
Análise de Elementos Finitos , Arritmias Cardíacas , Lesões por Armas de Eletrochoque , Eletrochoque , Humanos , Fibrilação Ventricular , Armas
10.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 2185-2190, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29060330

RESUMO

INTRODUCTION: We have previously published about TASER® conducted electrical weapons (CEW) compliance with international standards. CEWs deliver electrical pulses that can inhibit a person's neuromuscular control or temporarily incapacitate. An eXperimental Rotating-Field (XRF) waveform CEW and the X2 CEW are new 2-shot electrical weapon models designed to target a precise amount of delivered charge per pulse. They both can deploy 1 or 2 dart pairs, delivered by 2 separate cartridges. Additionally, the XRF controls delivery of incapacitating pulses over 4 field vectors, in a rotating sequence. As in our previous study, we were motivated by the need to understand the cardiac safety profile of these new CEWs. The goal of this paper is to analyze the nominal electrical outputs of TASER XRF and X2 CEWs in reference to provisions of all relevant international standards that specify safety requirements for electrical medical devices and electrical fences. Although these standards do not specifically mention CEWs, they are the closest electrical safety standards and hence give very relevant guidance. METHODS: The outputs of several TASER XRF and X2 CEWs were measured under normal operating conditions. The measurements were compared against manufacturer specifications. CEWs electrical output parameters were reviewed against relevant safety requirements of UL 69, IEC 60335-2-76 Ed 2.1, IEC 60479-1, IEC 60479-2, AS/NZS 60479.1, AS/NZS 60479.2, IEC 60601-1 and BS EN 60601-1. RESULTS AND CONCLUSION: Our study confirmed that the nominal electrical outputs of TASER XRF and X2 CEWs lie within safety bounds specified by relevant standards.


Assuntos
Armas , Lesões por Armas de Eletrochoque , Eletrochoque , Humanos
11.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 2191-2196, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29060331

RESUMO

INTRODUCTION: The TASER® conducted electrical weapon (CEW) delivers electrical pulses that can temporarily incapacitate subjects. For existing CEW models, we have previously presented the distribution of currents in tissues posterior to the sternum and their likelihood of triggering cardiac arrhythmias. New models, the eXperimental Rotating-Field (XRF) waveform CEW (in development) and the X2 CEW (released) have not been investigated. Both the XRF and X2 CEWs target a precise amount of delivered charge per pulse, 64 µC and 62 µC, respectively. The goal of this study was to numerically model the thoracic cage attenuation of currents and electric fields delivered by the new CEWs and to find whether the heart is shielded from the induction of any dangerous arrhythmias. METHODS AND RESULTS: Finite element modeling (FEM) was used to approximate the current density and electric field strength in tissues around the thoracic cage. FEM boundary conditions were set to correspond to output waveforms of the new CEWs, the XRF and the X2. We analyzed a CEW dart deployment scenario that had both darts located over the anterior aspect of the sternum. We found that the sternum and thoracic cage provided significant attenuation of currents and electrical fields. CONCLUSION: The sternum and the thoracic cage significantly attenuated currents and electric fields delivered by XRF and X2 CEWs. These tissues `shielded' the heart against potentially dangerous cardiac arrhythmias. The shorter durations and reduced amount of charged delivered by the XRF and the X2 CEWs resulted in increased cardiac safety margins.


Assuntos
Armas , Arritmias Cardíacas , Eletricidade , Coração , Humanos , Esterno
12.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 3712-3718, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29060705

RESUMO

INTRODUCTION: A rigorous method for assessing the Ventricular Fibrillation (VF) risk of a Random Complex Waveform (RCW) has not been previously available. Real-life hazardous events motivated us to develop such method. An RCW is observable and recordable. It consists of multiple different components randomly added one to the other. Assessment for VF risk exists for non-random waveforms, particularly VF thresholds for 50/60 Hz alternating currents, but not for RCWs. METHODS: We developed a method which considers exposure to a segment of an RCW. It transforms complex segment exposure to values which can be compared with AC root-mean-square (rms) magnitude/duration curves, for determination of VF risk. Human contact could occur for any given time duration within the segment. The current of most risk is the greatest found for all possible instances of that duration. This is termed the "Probable Current" (PC) for that duration. All possible exposure durations in the waveform segment are considered, giving a set of PCs, thus allowing the plotting of a PC curve. The PC set is compared with a criterion for VF risk, termed the Justified Current (JC) curve. RESULTS: The theory is presented. Demonstrations and examples are given. Code is shown for generating the PC curve. CONCLUSION: VF risk can be found for an RCW using the rigorous algorithm presented. SIGNIFICANCE: The VF for RCWs has not been considered previously. A rigorous statement of a method for VF risk assessment allows extension from regular waveforms to RCWs.


Assuntos
Coração , Arritmias Cardíacas , Cardioversão Elétrica , Eletrocardiografia , Humanos , Fibrilação Ventricular
13.
J Forensic Sci ; 61(6): 1556-1562, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27429421

RESUMO

Concern has been raised over the infection risk of the TASER electrical weapon since the probes penetrate the skin. The manufacturing process produces unsterilized probes with a 5% rate of Staphylococcus aureus contamination. Voluntary recipients (n = 208) of probe exposures were surveyed and there were no self-observations of infection. With over 3.3 million probe landings, there have been 10 case reports of penetrations of sensitive tissue with no reported infections. The electrical field was modeled and found that the electrical pulses generate a field of over 1200 V/mm on the dart portion. This is sufficient to sterilize the dart via electroporation. Electrical weapon probes appear to have a very low (possibly zero) rate of infection. The factors leading to this low infection rate appear to be a manufacturing process producing a low rate of bacterial contamination and the pulses sterilizing the dart via electroporation.


Assuntos
Infecções , Staphylococcus aureus/isolamento & purificação , Armas , Lesões por Armas de Eletrochoque , Humanos , Risco
14.
Annu Int Conf IEEE Eng Med Biol Soc ; 2016: 2343-2348, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28268796

RESUMO

Small swine are the most common model now used for electrical safety studies. Because of the significant anatomical and electrophysiological differences and the effect of animal size on the ventricular fibrillation (VF) threshold, there are concerns that these differences may exaggerate the risks of electrical devices to humans. We chose, as an illustrative and relevant example, swine studies of the TASER® conducted electrical weapon (CEW) as it has numerous published VF studies. We reviewed the published electrical swine safety studies for CEWs and compared them to finite element modeling studies, electrical safety standards, and epidemiological experience from field usage. We also compared the body weights of the swine to those of law enforcement arrest-related deaths. Studies of small swine exaggerate the risks of CEWs to humans. This conclusion may be extrapolated to suggest that the use of small swine for electrical safety studies should be questioned in general.


Assuntos
Eletrochoque/efeitos adversos , Fibrilação Ventricular/etiologia , Animais , Humanos , Aplicação da Lei , Modelos Animais , Risco , Suínos , Armas
15.
Annu Int Conf IEEE Eng Med Biol Soc ; 2016: 5241-5245, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28269446

RESUMO

INTRODUCTION: The TASER® conducted electrical weapon (CEW) is best known for delivering electrical pulses that can temporarily incapacitate subjects by overriding normal motor control. The alternative drive-stun mode is less understood and the goal of this paper is to analyze the distribution of currents in tissues when the CEW is operated in this mode. METHODS AND RESULTS: Finite element modeling (FEM) was used to approximate current density in tissues with boundary electrical sources placed 40 mm apart. This separation was equivalent to the distance between drive-stun mode TASER X26™, X26P, X2 CEW electrodes located on the device itself and between those located on the expended CEW cartridge. The FEMs estimated the amount of current flowing through various body tissues located underneath the electrodes. The FEM simulated the attenuating effects of both a thin and of a normal layer of fat. The resulting current density distributions were used to compute the residual amount of current flowing through deeper layers of tissue. Numerical modeling estimated that the skin, fat and skeletal muscle layers passed at least 86% or 91% of total CEW current, assuming a thin or normal fat layer thickness, respectively. The current density and electric field strength only exceeded thresholds which have increased probability for ventricular fibrillation (VFTJ), or for cardiac capture (CCTE), in the skin and the subdermal fat layers. CONCLUSION: The fat layer provided significant attenuation of drive-stun CEW currents. Beyond the skeletal muscle layer, only fractional amounts of the total CEW current were estimated to flow. The regions presenting risk for VF induction or for cardiac capture were well away from the typical heart depth.


Assuntos
Condutividade Elétrica , Especificidade de Órgãos , Armas , Derme/fisiologia , Eletrodos , Análise de Elementos Finitos , Coração/fisiopatologia , Humanos , Músculo Esquelético/fisiologia , Fibrilação Ventricular/fisiopatologia
16.
Annu Int Conf IEEE Eng Med Biol Soc ; 2015: 7208-13, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26737955

RESUMO

UNLABELLED: Standards, including IEC 60479-1 and -2, provide current-based ventricular fibrillation thresholds (VFT) for stimuli durations between 0.1 ms and 10 s. It has been established that the amount of electrical charge, not the current calculated by root-mean-square, is most representative of the effects of cardiac stimulation. There are no unified models that present transthoracic charge VFTs for a wide range of stimuli durations. This work proposes a new unified charge model applicable to transthoracic stimuli durations ranging over 1 µs - 300 s. VFTs were compiled from our previous animal work and from other published reports, including from the studies that provided the raw data for IEC 60479-1 and -2. Our study goal was to cover a wide range of stimuli durations, for which reliable data exists. Consistent data were found for stimuli durations covering the range of 1 µs - 300 s where VFTs were expressed as charge. The model predicted a transthoracic charge VFT of 1 mC at 1 µs duration. The charge VFT increased with stimulus duration and reached 10 C at 300 s. Presenting the first charge-based transthoracic VFT model covering stimuli durations over 1 µs - 300 s, we found 3 behavioral regions of charge VFT vs. DURATION: For short stimuli durations, 1 µs - 10 ms, VFTs followed a classic Weiss charge strength-duration curve. For long stimuli, longer than 5 s, charge VFTs can be approximated using a 38 mArms constant current model. From 10 ms to 5 s, charge VFTs tracked through a transition zone that could be approximated as a constant charge model Q≈100 mC.


Assuntos
Estimulação Elétrica/efeitos adversos , Modelos Cardiovasculares , Fibrilação Ventricular/etiologia , Animais
17.
Artigo em Inglês | MEDLINE | ID: mdl-26738091

RESUMO

This project developed and evaluated a smartphone-based system to improve mobility and transportation access for the cognitively impaired. The proposed system is intended to allow the cognitively impaired to use public transportation systems, community transportation and dedicated transportation services for the disabled with greater ease and safety. Individuals with cognitive disabilities are often unable to operate an automobile, or may require a prolonged recovery period before resuming driving. Public transportation systems represent a significant means to allow these individuals to maintain independence. Yet public transportation systems can pose significant challenges to individuals with cognitive impairment. The goal of this project is to develop a system to reduce these barriers via a technological solution consisting of components developed both for the cognitively impaired user and their caregiver or family member. The first component consists of a cognitive prosthetic device featuring traditional memory cueing and reminders as well as custom location-based transportation specific functions. This cognitive mobility assistant will leverage the computing power and GPS location determination capabilities of inexpensive, powerful smart phones. The second component consists of a management application which offers caregivers the ability to configure and program the reminder and transit functions remotely via the Internet. Following completion of the prototype system a pilot human test was performed with cognitively disabled individuals and family members or caregivers to assess the usability and acceptability of both system components.


Assuntos
Transtornos Cognitivos/reabilitação , Pessoas com Deficiência/reabilitação , Smartphone , Transportes/instrumentação , Humanos
18.
Artigo em Inglês | MEDLINE | ID: mdl-26736209

RESUMO

Telecoils in hearing aids serve a dual purpose: to enhance telephone conversation and enable hearing aids to serve as a wireless interface for public audio broadcasts. When broadcasting audio signals, the signal is transmitted to the telecoil sensor (a magnetic field sensor located in the hearing aid) via magnetic energy from an induction wire loop located near the listener. This induction loop can be a small assembly located in the handset of the telephone or a large wire loop within a public venue like a theatre. Current hearing aids detect the magnetic signal using a single telecoil. If the telecoil is not aligned with the magnetic field, the strength of the detected signal is diminished. Unfortunately, public induction loops and telephone handsets seldom share a common alignment to the hearing aid, leading to sub-optimal performance by one or both in hearing aids available today. In this research, a prototype behind-the-ear (BTE) hearing aid with tri-axial telecoils was developed and DSP algorithms to process and combine the three signals were developed. The resulting hearing aid was evaluated in a human trial and provided better performance than a similar quality conventional telecoil hearing aid.


Assuntos
Percepção Auditiva/fisiologia , Auxiliares de Audição , Adulto , Idoso , Algoritmos , Humanos , Pessoa de Meia-Idade , Processamento de Sinais Assistido por Computador , Razão Sinal-Ruído
19.
Artigo em Inglês | MEDLINE | ID: mdl-26736265

RESUMO

The TASER(®) conducted electrical weapon (CEW) delivers electrical pulses that can temporarily incapacitate subjects. We analyzed the cardiac fibrillation risk with TASER CEWs. Our risk model accounted for realistic body mass index distributions, used a new model of effects of partial or oblique dart penetration and used recent epidemiological CEW statics.


Assuntos
Eletrochoque/métodos , Fibrilação Ventricular/etiologia , Índice de Massa Corporal , Eletrochoque/instrumentação , Análise de Elementos Finitos , Humanos , Risco
20.
Annu Int Conf IEEE Eng Med Biol Soc ; 2015: 1343-8, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26736517

RESUMO

INTRODUCTION: The ubiquitous electric fence is essential to modern agriculture and has saved lives by reducing the number of livestock automobile collisions. Modern safety standards such as IEC 60335-2-76 and UL 69 have played a role in this positive result. However, these standards are essentially based on energy and power (RMS current), which have limited direct relationship to cardiac effects. We compared these standards to bioelectrically more relevant units of charge and average current in view of recent work on VF (ventricular fibrillation) induction and to existing IEC AC current limits. METHODS AND RESULTS: There are 3 limits for normal (low) pulsing rate: IEC energy limit, IEC current limit, and UL current limit. We then calculated the delivered charge allowed for each pulse duration for these limits and then compared them to a charge-based safety model derived from published human ventricular-fibrillation induction data. Both the IEC and UL also allow for rapid pulsing for up to 3 minutes. We calculated maximum outputs for various pulse durations assuming pulsing at 10, 20, and 30 pulses per second. These were then compared to standard utility power safety (AC) limits via the conversion factor of 7.4 to convert average current to RMS current for VF risk. The outputs of TASER electrical weapons (typically < 100 µC and ~100 µs duration) were also compared. CONCLUSIONS: The IEC and UL electric fence energizer normal rate standards are conservative in comparison with actual human laboratory experiments. The IEC and UL electric fence energizer rapid-pulsing standards are consistent with accepted IEC AC current limits for commercially used pulse durations.


Assuntos
Eletricidade , Arritmias Cardíacas , Cardioversão Elétrica , Estimulação Elétrica , Coração , Humanos , Fibrilação Ventricular
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