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Electrical stimulation : ウィキペディア英語版 | Functional electrical stimulation
Functional electrical stimulation (FES) is a technique that uses electrical currents to activate nerves innervating extremities affected by paralysis resulting from spinal cord injury (SCI), head injury, stroke and other neurological disorders. FES is primarily used to restore function in people with disabilities. It is sometimes referred to as neuromuscular electrical stimulation (NMES).〔M. Claudia et al.,(2000), Artificial Grasping System for the Paralyzed Hand, International Society for Artificial Organs, Vol 24 No.3〕 ==Principles==
Neurons are electrically active cells. The presence of an electric field in nervous tissue may lead to the depolarization of neural cell membranes and thereby induce firing of action potentials . FES devices take advantage of this property to electrically activate nerve cells, which then may go on to activate muscles or other nerves. However, special care must be taken in designing safe FES devices, as passing electric current through nervous tissue can lead to adverse effects such as decrease in excitability or cell death. This may be due to thermal damage , electroporation of the cell membrane , toxic products from electrochemical reactions at the electrode surface , or overexcitation of the target neurons . Typical stimulation protocols used in clinical FES involves trains of electric pulses. Biphasic, charged balanced pulses are employed as they improve the safety of electrical stimulation and minimize some of the adverse effects. Pulse width, charge per phase and frequency are the key parameters that define safety and effectiveness of FES . Furthermore, the polarity of a biphasic pulse, which can be either cathodic-first or anodic-first, affects the threshold for activation for nervous tissue . For peripheral nervous stimulation, cathodic-first pulses have lower thresholds, resulting in more efficient for charge delivery. For surface cortical simulation, where axons are perpendicular to the electrode surface, anodic first pulses are more efficient.
抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Functional electrical stimulation」の詳細全文を読む
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