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OVERVIEW OF ELECTROTHERAPY
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Electrotherapy Is Not as Challenging as It May Seem
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Clinical electrotherapy is sometimes considered challenging and difficult to comprehend. This is far from reality if one possesses some basic understanding of the fundamentals of electricity and charge, anatomy and physiology, and clinical application. This chapter will set the foundations to make clinical electrotherapy both understandable and clinically useful for clinicians and, perhaps more importantly, clinically beneficial to patients. Despite the varied terminology and uses of electrotherapeutics across the many areas of rehabilitation, there is one common purpose: application of electrical stimulation (ES) to elicit or facilitate some desired therapeutic response. Whether ES is used to activate skeletal muscle for strengthening or improving volitional movement, relaxing skeletal muscle to facilitate functional activity, decreasing pain, improving circulation, or facilitating tissue healing, all of these clinically important effects are based on the stimulation of tissues from applied electric currents.
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This chapter will delineate the steps to learning ES in a way that will be user-friendly, trying to minimize confusion as you develop new terminology and understanding. This can be likened to learning to drive a car; if you are taught to drive in one particular make or brand of car, you are likely to be successful if you use those same skills, knowledge, and experiences when driving a comparable but different brand of car. While some of the knobs, dials, buttons, and other features of cars will vary, the fundamental procedures to operate each are more similar than different.
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The overall purpose of this chapter is to address the fundamental principles of electricity and electrical charge that underlie the therapeutic effects of clinical electrotherapy. This chapter and following ones will present not only the “how,” but also the “when,” “why,” and “what” of electrotherapy. Chapters 11, 13, and 14 will present more specific applications of clinical electrotherapy for patients with pain (Chapter 11), musculoskeletal impairment (Chapter 13), and neurological impairment (Chapter 14).
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PRINCIPLES OF ELECTRICITY: MAKING THE PHYSICS MAKE SENSE
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To begin considering clinical applications and use of electrotherapy without first addressing the fundamentals of electricity is like asking someone to play a game without telling them how. Without some prior knowledge and understanding of the basic rules and strategy of the game, it may appear as if someone is truly playing the game, but eventually the outcome will reveal the lack of knowledge. So it is with clinical electrotherapy—without an understanding of the fundamentals, clinical effectiveness is far less likely. A functional and useful understanding of electrotherapy must begin with the basics.
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Charge is the fundamental property of electromagnetic force and underlies the mechanisms by which living cells communicate with one another, that being depolarization and repolarization. Measured in coulombs (C) or microcoulombs (pC), charge ...