Functional Electrical Stimulation for Ambulation by Paraplegics: Twelve Years of Clinical Observations and Systems Studies.

Graupe D, Kohn KH. Melbourne, FL 32902-9542, Krieger Publishing Co, 1994, hardback, 194 pp, illus, $39.50.

This text is primarily aimed at physical therapists and physiatrists, providing information about the use of functional electrical stimulation (FES) for unbraced standing and ambulation in patients with spinal cord injury. It details the authors' development and use of the Parastep System at the Michael Reese Hospital in Chicago, Ill. This system, as described, is designed to allow patients with paraplegia to ambulate independently between 20 to 500 steps per session. The standard system includes a portable stimulator unit that is worn at the waist, a walker with hand controls, four pairs of electrodes, and, for some patients, ankle-foot orthoses.

This compact text is divided into 11 chapters. The first chapter provides an introduction to spinal cord injury and FES; the second chapter gives a review of the physiology of nerve excitation.

The next three chapters describe the system including the system hardware, the stimulating parameters of the electrical signals, the technical specifications of the stimulator, and the operating software. The current system is manually operated, with user-initiated controls, but the authors also describe the potential development and marketing of a system with electromyographic controls.

Chapter 6 provides a brief outline of the clinical criteria and contraindications for use of the Parastep System. Included are guidelines for consideration of the medical, physical, and emotional makeup of the successful user of the system. The next two chapters detail the system operating instructions and the strategies for patient training. The potential options for electrode sizes and placements, and function and use of the walker are described in chapter 7. The authors also describe the possible addition of two channels of electrical stimulation, especially for use with patients with injuries at the T-7 level or higher, that may be useful for improving trunk stability and upright posture in these patients. Chapter 8 is one of the most valuable chapters for physical therapists. Explicit and clear instructions are provided for training a patient in the use of the Parastep System. Included are techniques for sit to stand, ambulation, turning, and backward maneuvering.

Chapters 9 and 10 describe clinical observations from the authors' clinical facility and from other sites using the Parastep System. The authors suggest the need for consistent practice with the system, and describe the ambulation performance of their patients. The results of cardiopulmonary and muscle function studies and the incidence of complications in their patients are also described.

The final chapter includes references to other FES systems available for ambulation for patients with spinal cord injury, the socioeconomic impact of spinal cord injury and FES, and some recommendations for future directions.

The writing style in this text is clear and straightforward, even though the topics covered range from the anecdotal and descriptive to more research and technology oriented. In several places in the text the authors describe new directions for the software and hardware that is currently being tested but not yet commercially available (such as the use of telemetry instead of direct wiring of electrodes and the controlling of the system by electromyography). The authors do provide some current references, but the citations are limited, with no attempt to provide a comprehensive or even representative literature sampling.

This text would be useful for physical therapists who are currently using, or considering using, the Parastep System for ambulation with patients with paraplegia. This text provides ample details regarding the current system hardware, software, and training guidelines, and insight into what is likely to be commercially available in the future. In addition, it describes the historical development of the Parastep System. The authors report, for example, on the development of the system control strategies and the need for the control to be balanced with the goals of producing a system that is fail-safe and nonrobotic. This is an interesting perspective, not typically available to the purchaser of commercially available equipment.

Reading the text, it becomes clear that the authors have been actively involved in the design, development, and testing of the FES system described, and care strongly about the potential benefits to be derived from its use. Although the authors do not identify any affiliation with the commercial organization that manufactures the system, I would have appreciated knowing explicitly if the authors have any direct interest in the commercial venture.

The text would be less useful for a therapist interested in obtaining an overview of the use of FES in patients with spinal cord injuries or a comparison of FES systems currently available, and would not be appropriate as a course text in an entry-level physical therapy program.

David J Miller, PhD, PT Springfield College Springfield, Mass

Dr Miller is an associate professor in the department of physical therapy of Springfield College. His professional interests include the clinical uses of electromyography and occupational biomechanics.