Статья на тему "устройства протезирования"
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Аннотация Представленная статья на тему “устройства протезирования” включает в себя сведения о происхождении, функциях и истории развития протезирования в мире. Протезирование помогает больным людям частично восстановить функции утраченных конечностей и помогает им вести привычный образ жизни. Summary The presented article on the topic “prosthetic devices " includes information about the origin, functions and history of the development of prosthetics in the world. Prosthetic devices help sick people partially restore the functions of their lost limbs and help them lead a normal lifestyle. Prosthetic Devices Prosthetic devices are artificial components designed to replace a part of the human body that is missing, either due to accident or a birth defect. When discussing prosthetics, many people think only of artificial arms and legs. However, there are other types of prosthetics that are in common use, such as dentures. The exact origin of prosthetic devices is not known. There are evidences dating back to ancient Egypt of hands, arms and feet being fashioned to take the place of limbs lost during wars or due to accidents. In some cases, the prosthetic devices were mainly aimed at providing function and did not bear much resemblance to the body part they replaced. However, other devices were created that focused more on appearance and less on function. In modern times, prosthetic devices come in many different forms. Dentures were once prepared using wood and other products. While functional, they did not necessarily provide the appearance of a set of healthy teeth. Today, partial and full denture plates are often indistinguishable from real teeth. Advances in technology have also made it possible to design custom dentures for a more comfortable fit as well as a superior appearance. The progress of artificial limbs can be seen over the centuries. From a simple wooden peg to the intuitive prosthetic legs of today, technology has made wearing and operating prosthetic devices of this type much easier. One of the most cutting-edge technologies used to control prosthetic limbs is called targeted muscle reinnervation (TMR) and was developed by Dr. Todd Kuiken at the Rehabilitation Institute of Chicago. To understand TMR, you need to know some basic physiology. Your brain controls the muscles in your limbs by sending electrical commands down the spinal cord and then through peripheral nerves to the muscles. Now imagine what would happen to this information pathway if you had a limb amputated. The peripheral nerves would still carry electrical motor command signals generated in the brain, but the signals would meet a dead end at the site of amputation and never reach the amputated muscles. In the surgical procedure required for TMR, these amputated nerves are redirected to control a substitute healthy muscle elsewhere in the body. For example, the surgeon might attach the same nerves that once controlled a patient's arm to a portion of the patient's chest muscles. After this procedure, when the patient attempts to move his or her amputated arm, the control signals traveling through the original arm nerve will now cause a portion of chest muscles to contract instead. This is valuable, because the electrical activity of these chest muscles can be sensed with electrodes and used to provide control signals to a prosthetic limb. The end result is that just by thinking of moving the amputated arm, a patient causes the prosthetic arm to move instead. If electrodes can sense the electricity caused by muscle contractions, why can't they just go to the source of the information and measure the electrical signals carried in the nerves, or even the brain? The answer is that they can, but recording from the brain and nerves is more challenging for several reasons. For example, electrical signals in the brain and nerves are very small and hard to access. The field of neural interfacing is dedicated to developing ways to listen and communicate with the brain and nerves. As an example of neural interfacing technology, scientists can implant micro-scale electrodes in the brain to listen in on brain activity. When the patient mentally tries to move his or her amputated limb, the microelectrodes can intercept motor command signals generated in the brain, and these signals can then be used to control a prosthetic device. One exciting implementation of this technology comes from Dr. Miguel Nicolelis lab at Duke University. Remarkable video footage documents the ability of monkeys implanted with microelectrodes to use their thoughts to control a prosthetic arm to feed themselves on snacks. Future advances in neural interfacing will allow artificial devices to more effectively stimulate the nerves or brain in order to restore a sense of touch and allow patients to feel their artificial limb. This capability will go a long way in closing the gap between prosthetic limbs and the natural limbs they're designed to replace. These types of technological innovations are just some of the examples that show how the field of prosthetics is constantly advancing. While the challenges are great, remarkable progress has been made over the past few decades, and dedicated researchers around the globe are working each day to make prosthetic limbs as close as possible to the real thing. Innovations in Medical Sensors Biomedical electronics research is being driven by the aging "baby-boomer" population and their medical needs. This phenomenon is spurring fast development of new biotechnologies and need for access to innovative means of medical diagnosis and treatment in preventive medicine. Subsequently, the technologies of implants and advanced wireless electronic media will help alleviate rising medical costs in today’s society and extend the average longevity with a quality life in our later years. The brain. Closed-loop deep brain stimulation (CDBS), for people with epilepsy, Parkinson's Disease (PD) or even obsessive compulsive disorder (OCD), is a prime example of implementation of a biomedical electronic solution that offers an enhancement to the quality of life in someone afflicted with such conditions. The DBS system detects a patient's electroencephalogram (EEG) and automatically generates DBS electrical pulses to prevent the onset of an epileptic seizure or even helps lessen the tremors of PD. DBS sends specific stimuli to different regions of the brain. DBS is used in patients who are resistant to drug treatment and those who suffer from motor fluctuations and tremors. Similar to a cardiac pacemaker, the DBS uses a neurostimulator to generate and deliver high-frequency electric pulses into subthalamic nucleus (STN) or globus pallidus internus (GPi) portions of the brain through extension wires and electrodes. The neurostimulator is typically programmed post-surgery by trained technicians to find the most effective signal parameters for alleviating Parkinson's symptoms. A proposed basic design of a CDBS is as follows: the CDBS device directly interfaces with recording and stimulation electrodes. Eight recording electrodes are implanted in the motor cortex and 64 stimulating electrodes are implanted in the STN portion of the brain. The 64-channel point-controllable stimulation enables the formation of various stimulus patterns for the most effective treatment of Parkinson's symptoms. The collected neural signals from the embedded microelectrodes should be conditioned using eight front-end low-noise neural amplifiers (LNAs). Due to the low-level amplitude of the neural spikes, integrated pre-amplifiers are sometimes used to amplify the small signals before the data conversion. The front-end design needs to be low noise to guarantee the signal integrity. The front-end band-pass LNAs typically have a gain on the order of 100 and the LNA input design needs to minimize 1/f noise. A switched capacitor technique can be used for resistor emulation and 1/f noise reduction. The switched-capacitor circuit modulates the signal so that 1/f noise may be reduced to below thermal noise. The switched-capacitor amplifying filter performs well in recording neural spikes and field potential, simultaneously. The LNA's are in turn multiplexed to a single high-dynamic-range logarithmic amplifier front end into an analog-to-digital converter (ADC) making analog automatic gain control unnecessary. To cover the entire range of both small-signal neural spikes and large-signal local field potential (LFP) responses from the brain stimulation, the high-dynamic-range ADC is needed to digitize all the desired neural information. The logarithmic amplifier, used in front of the ADC, is able to achieve this needed dynamic range. Logarithmic encoding is well-suited to neural signals and is efficient, since a large dynamic range can be represented with a short word length. To save area and power consumption, the relatively large-dynamic-range ADC is used, making analog automatic gain control unnecessary. The ADC needs a digital filter which separates the low frequency neural field potential signal from the neural spike energy. Separation of the low-frequency field potential from the higher frequency spike energy can be done with a 22-tap finite-impulse-response (FIR) Butterworth-type digital filter. Using digital filters instead of analog or mixed-signal filters provides many advantages. First of all, a digital filter is programmable so that its operation may be adjusted without modifying hardware while generally an analog filter may be changed only by modifying the design. A digital filter is used for diplexers to separate two frequency bands of spikes and LFPs. While analog filter circuits are subject to drift and are dependent on temperature, a digital filter does not suffer from these issues, and is extremely robust with respect to both time and temperature. The electrical stimulator generates 64 channels of biphasic charge-balanced current stimulation. A dedicated controller generates these stimulation patterns via an I/O channel to control the 64 current-steering DACs. The 64 DACs can be formed as a cascade of a single shared 2-bit coarse current DAC and 64 individual bi-directional 4-bit fine DACs or other similar configuration. The DAC has 48 possible current values. One can use a fine ADC and a polarity switch selects the positive or negative DAC output to achieve charge-balanced bi-phasic stimulation, helping to reduce the risk of long-term tissue damage. For the next generation of DBS and tools to help researchers understand the mystery of the brain, companies are developing the Bi-directional Brain-machine interface. This technique promises to be a major development tool in the frontier of brain research once all lab tests are completed and approved for use with human brain studies in the near future. Right now it is in preclinical research. There are no approved products yet. The heart. "Small size", "wireless", and "non-contact" are words that could never have been associated with ECG devices in the past. New developments in electronics now enable more compact/portable designs, some that include wireless capability and even those sensors that require no physical or resistive contact with the body. Basic functions of an ECG machine include ECG waveform display, either through LCD screen or printed paper media, and heart rhythm indication as well as simple user interface through buttons. More features, such as patient record storage through convenient media, wireless/wired transfer and 2D/3D display on large LCD screen with touch screen capabilities, are required in more and more ECG products. Multiple levels of diagnostic capabilities are also assisting doctors and people without specific ECG training to understand ECG patterns and their indication of a certain heart condition. After the ECG signal is captured and digitized, it will be sent for display and analysis, which involves further signal processing. Prosthetic Devices Prosthetic devices are artificial components designed to replace a part of the human body that is missing, either due to accident or a birth defect. When discussing prosthetics, many people think only of artificial arms and legs. However, there are other types of prosthetics that are in common use, such as dentures. The exact origin of prosthetic devices is not known. There are evidences dating back to ancient Egypt of hands, arms and feet being fashioned to take the place of limbs lost during wars or due to accidents. In some cases, the prosthetic devices were mainly aimed at providing function and did not bear much resemblance to the body part they replaced. However, other devices were created that focused more on appearance and less on function. In modern times, prosthetic devices come in many different forms. Dentures were once prepared using wood and other products. While functional, they did not necessarily provide the appearance of a set of healthy teeth. Today, partial and full denture plates are often indistinguishable from real teeth. Advances in technology have also made it possible to design custom dentures for a more comfortable fit as well as a superior appearance. The progress of artificial limbs can be seen over the centuries. From a simple wooden peg to the intuitive prosthetic legs of today, technology has made wearing and operating prosthetic devices of this type much easier. One of the most cutting-edge technologies used to control prosthetic limbs is called targeted muscle reinnervation (TMR) and was developed by Dr. Todd Kuiken at the Rehabilitation Institute of Chicago. To understand TMR, you need to know some basic physiology. Your brain controls the muscles in your limbs by sending electrical commands down the spinal cord and then through peripheral nerves to the muscles. Now imagine what would happen to this information pathway if you had a limb amputated. The peripheral nerves would still carry electrical motor command signals generated in the brain, but the signals would meet a dead end at the site of amputation and never reach the amputated muscles. In the surgical procedure required for TMR, these amputated nerves are redirected to control a substitute healthy muscle elsewhere in the body. For example, the surgeon might attach the same nerves that once controlled a patient's arm to a portion of the patient's chest muscles. After this procedure, when the patient attempts to move his or her amputated arm, the control signals traveling through the original arm nerve will now cause a portion of chest muscles to contract instead. This is valuable, because the electrical activity of these chest muscles can be sensed with electrodes and used to provide control signals to a prosthetic limb. The end result is that just by thinking of moving the amputated arm, a patient causes the prosthetic arm to move instead. If electrodes can sense the electricity caused by muscle contractions, why can't they just go to the source of the information and measure the electrical signals carried in the nerves, or even the brain? The answer is that they can, but recording from the brain and nerves is more challenging for several reasons. For example, electrical signals in the brain and nerves are very small and hard to access. The field of neural interfacing is dedicated to developing ways to listen and communicate with the brain and nerves. As an example of neural interfacing technology, scientists can implant micro-scale electrodes in the brain to listen in on brain activity. When the patient mentally tries to move his or her amputated limb, the microelectrodes can intercept motor command signals generated in the brain, and these signals can then be used to control a prosthetic device. One exciting implementation of this technology comes from Dr. Miguel Nicolelis lab at Duke University. Remarkable video footage documents the ability of monkeys implanted with microelectrodes to use their thoughts to control a prosthetic arm to feed themselves on snacks. Future advances in neural interfacing will allow artificial devices to more effectively stimulate the nerves or brain in order to restore a sense of touch and allow patients to feel their artificial limb. This capability will go a long way in closing the gap between prosthetic limbs and the natural limbs they're designed to replace. These types of technological innovations are just some of the examples that show how the field of prosthetics is constantly advancing. While the challenges are great, remarkable progress has been made over the past few decades, and dedicated researchers around the globe are working each day to make prosthetic limbs as close as possible to the real thing. Устройства протезирования. Протезы-это искусственные компоненты, предназначенные для замены части человеческого тела, которая отсутствует либо из-за несчастного случая, либо из-за врожденного дефекта. Обсуждая протезирование, многие люди думают только об искусственных руках и ногах. Однако существуют и другие виды протезирования, которые широко используются, такие как зубные протезы. Точное происхождение протезов неизвестно. Существуют свидетельства, восходящие к Древнему Египту, о том, что руки, руки и ноги были созданы, чтобы заменить конечности, потерянные во время войн или в результате несчастных случаев. В некоторых случаях протезы были в основном направлены на обеспечение функции и не имели большого сходства с частью тела, которую они заменяли. Однако были созданы и другие устройства, которые больше фокусировались на внешнем виде и меньше на функциях. В наше время протезы бывают самых разных форм. Зубные протезы когда-то изготавливались с использованием дерева и других изделий. Будучи функциональными, они не обязательно обеспечивали внешний вид набора здоровых зубов. Сегодня частичные и полные пластины зубных протезов часто неотличимы от настоящих зубов. Достижения в области технологий также позволили разработать индивидуальные зубные протезы для более удобной посадки, а также превосходного внешнего вида. Прогресс протезов можно наблюдать на протяжении веков. От простого деревянного колышка до интуитивно понятных протезных ножек сегодняшнего дня технология значительно упростила ношение и эксплуатацию протезов этого типа. Одна из самых передовых технологий, используемых для контроля протезирования конечностей, называется целевой реиннервацией мышц (TMR) и была разработана доктором Тоддом Куикеном в Институте реабилитации Чикаго. Чтобы понять ПМР, вам нужно знать некоторые основы физиологии. Ваш мозг управляет мышцами ваших конечностей, посылая электрические команды вниз по спинному мозгу, а затем через периферические нервы к мышцам. Теперь представьте, что произойдет с этим информационным путем, если вам ампутируют конечность. Периферические нервы по-прежнему будут передавать сигналы управления электродвигателями, генерируемые в мозге, но эти сигналы встретят тупик в месте ампутации и никогда не достигнут ампутированных мышц. В хирургической процедуре, необходимой для ПМР, эти ампутированные нервы перенаправляются для управления заменой здоровой мышцы в другом месте тела. Например, хирург может прикрепить те же нервы, которые когда-то контролировали руку пациента, к части грудных мышц пациента. После этой процедуры, когда пациент пытается пошевелить своей ампутированной рукой, управляющие сигналы, проходящие через исходный нерв руки, теперь заставят часть грудных мышц сокращаться. Это ценно, потому что электрическая активность этих грудных мышц может быть измерена с помощью электродов и использована для подачи управляющих сигналов на протез конечности. Конечным результатом является то, что, просто думая о перемещении ампутированной руки, пациент заставляет двигаться протезную руку. |