This chapter describes the typical setup and clinical application of electrical stimulators based on the type of current delivered. Although each stimulation method is presented as a distinct modality, many generators are capable of producing multiple forms of electrical current. The information presented in the Biophysical Effects section for each modality should be supplemented with the information presented in Chapter 12. The setup and application protocol are described in generalized terms. Always familiarize yourself with the operator's manual of the specific equipment used.
• The diverse array of electrical stimulation units, techniques, and theories can make understanding the application of electrical stimulation difficult and can be further complicated by individual manufacturers creating their own terminology. A common question is “When do I use each type of stimulator or current?” In some cases, there is one obviously correct answer; in other cases, there may be more than one correct option; and in other cases electrical stimulation may not be appropriate.
It is important to remember that most effects of electrical stimulation are the direct result of the depolarization of sensory nerves, motor nerves, pain nerves, and, rarely, muscle fibers directly (see Fig. 12-13). The depolarization thresholds are sequential and cumulative; for example, motor nerves cannot be depolarized without also depolarizing sensory nerves.
Some electrical stimulators deliver only one type of current. Multimodalities are capable of generating many different types of therapeutic currents and may also include therapeutic ultrasound (Box 13-1). Some multimodalities allow for two patients to be treated simultaneously.
Box 13-1. MULTIMODALITIES
The development of microprocessors, advanced circuitry, and improved battery supplies has led to an evolution in the design and function of electrical stimulators. Once, each type of electrical stimulating current described in this chapter required a specific generator. Now a single microprocessor-based multimodality is capable of producing all of the current types described in Chapter 12 and may include other therapeutic agents, such as ultrasound.
Many multimodalities' output is selected based on the treatment goal, pain control or muscle reeducation, for example, rather than the type of current. In this case a menu function will display the current being used for the treatment.
The user simply selects the type of output desired, usually described by the type of current, and selects a preprogrammed treatment regimen (e.g., motor-level edema reduction, sensory-level pain control). The instrumentation and output controls are unique to each unit. Because of the differences among multimodalities, their use is not described in this text.
Some state practice acts may require that electrical stimulation devices be applied only under a physician's order. Clinicians must be aware of state practice acts governing their profession's use of these devices as well as the policies and procedures for use at their institution. Likewise, an appropriately credentialed individual should supervise use of these devices.
Basic Guidelines for the Setup ...