OVERVIEW OF ELECTROTHERAPY
Electrotherapy Is Not as Challenging as It May Seem
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 understandable and, more importantly, clinically useful and beneficial to patients. Despite the varied terminology and uses of electrotherapeutics across the many areas of rehabilitation, there is one common purpose: application of stimulation to elicit or facilitate some desired therapeutic response. Whether electrical stimulation (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 are based on the stimulation of tissues from applied electric currents.
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 brand of car, you are likely to be successful if you use those same skills, knowledge, and experience when driving a comparable vehicle; therefore, effectiveness is based on a competent knowledge and application of fundamental basics.
The overall purpose of this chapter is to address the fundamental principles of electricity and electrical charge that underlie the therapeutic effects for which electrotherapy is used. This chapter and the following 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).
PRINCIPLES OF ELECTRICITY: MAKING THE PHYSICS MAKE SENSE
To discuss 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 less likely. A functional and useful understanding of electrotherapy must include and begin with the basics.
Charge is the fundamental underlying property of electromagnetic force and serves as the mechanism by which living cells communicate with one another. Measured in coulombs (C) or microcoulombs (μC), charge is obtained by the addition or removal of electrons and occurs when atoms of elements are acted upon by external physical forces such as friction, heat, and chemical or electrical ...