Physical Therapy by Robots?
Researchers design Robotic Stepper to help patients with SCI walk again
Depending on your perspective, it's either an exhilarating breakthrough in paralysis research, or an eerie glance into a future world of over-automation in which PT is performed by robots.
UCLA neruophysiologists and NASA engineers have teamed up to create a prototype robotic stepping device that the medical community hopes can help patients with spinal cord injury walk again. The stepper resembles a treadmill with robotic arms, and will feature a harness to support the patient's weight. The arms resemble knee braces that attach to patients' legs, guiding them through stepping motions on the moving treadmill.
"[This device] can potentially help some people who are now wheelchair-bound take their first steps," said Jim Weiss, program manager for collaborative neural repair at NASA's Jet Propulsion Laboratory (JPL). "This system can do the work of four therapists, and help monitor a patient's progress in a controlled manner."
Spinal Cord May Have the Ability to "Learn"
The robotic stepper was created to capitalize on recent findings by V. Reggie Edgerton, PhD, and others that reveal that the spinal cord holds the ability to command the legs to walk without involving the brain (see "Taking a Stand Against Paralysis," ADVANCE for Physical Therapists, April 17, 2000).
"One of the key elements here is that the spinal cord is very smart," said Dr. Edgerton, professor in the departments of physiological science and neurobiology at UCLA. "[It has the] ability to interpret and respond to complex information by generating activation of the appropriate muscles. We generally assume this information has to go up to the brain, that the brain has make sense of it, and only then do you respond. But the spinal cord is capable of processing a lot of that information [itself]."
This theory is what drives much of the research currently being done into bodyweight-supported ambulation, which until now required the carefully coordinated efforts of several therapists lifting and placing each limb in proper order.
"Some rehabilitation centers around the world are starting programs that will allow therapists to train individuals with spinal injuries, stroke and perhaps other neuromotor disorders to improve their mobility and stepping capacity," Dr. Edgerton explained. "This robotic device could help therapists in those rehabilitation efforts."
The theory is not without its critics. Steven L. Wolf, PhD, PT, director of rehabilitation medicine research at Emory University, Atlanta, wonders whether the spinal cord can be trained to guide real-life walking. He told WebMD that it is still uncertain whether the success of treadmill training wears off over time, and warns that the strenuous training may not be suitable for patients with heart problems or other medical conditions.
Still, bodyweight-supported ambulation has shown promise in patients with incomplete SCI, said Dr. Edgerton, who co-led the development team with Weiss. Many patients are able to walk without assistance after intensive training, and it remains the subject of a number of cutting-edge projects at leading paralysis research centers such as Atlanta's Shepherd Center and the Miami Project to Cure Paralysis.
Highly sensitive sensors on the robotic stepper collect up to 24 different data readings of the patient's activity, such as force, speed, acceleration, resistance and number of steps. A computer connected to the device displays the information on the screen for the therapist to monitor. While therapists currently performing this training can only observe and objectively monitor these factors, precise computerized measurements allow therapists to monitor day-to-day progress, provide valuable information on the effectiveness of the therapy, and adjust treatment as needed.
"With the computer technology we have now, we can integrate the robotics with the [brain and nerve function] of the patient and understand the idiosyncrasies of each person's body," said Weiss, adding that the robotic stepper may also aid future astronauts to walk safely after prolonged periods in space. "As [patients] are trained, they can decrease the support and carry more and more of their body weight themselves, eventually doing away with the harness altogether."
JPL and UCLA are actively pursuing efforts to commercialize the robotic system. JPL supported UCLA in filing a patent application on August 21 of last year. With modifications, the training concept can be applied to other neurological disorders such as stroke and palsy, said Dr. Edgerton.
The Jet Propulsion Laboratory, located near Pasadena, CA, is managed for NASA by the California Institute of Technology. JPL is the lead center for robotic exploration of the solar system, and conducts tasks for a variety of other federal agencies in addition to NASA. The robotic stepper is just one of several projects currently in development at UCLA's Brain Research Institute and at JPL. JPL spacecraft have visited all known planets except Pluto.
The robotic stepper is still in the development phase, but could be studied in UCLA clinical trials as early as three years from now.
Jonathan Bassett is on staff at ADVANCE, and can be reached at JBassett@merion.com