Robotic ankle training for CP transitions from lab to clinic

Robotic training device setup. (Reprinted with permission from Sukal-Moulton T, Clancy, T, Zhang LQ, Gaebler-Spira D. Clinical application of a robotic ankle training program for cerebral palsy compared to the research lab- oratory application: Does it translate to practice? Arch Phys Med Rehabil 2014 May 1. [Epub ahead of print])

Home device use could be next step

By Hank Black

A robotic system developed at the Rehabilitation Institute of Chicago (RIC), previously shown to have efficacy in a research lab setting, is also effective when used in a physical therapy clinic for ankle training in children with cerebral palsy (CP), according to a new RIC study.

In the clinic study, researchers demonstrated the feasibility and effectiveness of using robotic-assisted therapy in a busy after-school setting. Their protocol was associated with significant improvements in participants’ plantar flexor and dorsiflexor range of motion (ROM), strength, spasticity, mobility, balance, and selective control of the lower extremity, although not the gross motor function measure.

The in-clinic findings appeared online in May 2014 in the Archives of Physical Medicine and Rehabilitation. The results compared favorably with outcomes from the pilot lab-based study, which was published in the May 2011 issue of Neurorehabilitation and Neural Repair.

“A critical component of the training may be the use of the robotic device with an intensive, therapist-guided program to maximize gains achieved with the device, but this question remains to be formally investigated,” said first author Theresa Sukal-Moulton, PT, DPT, then a doctoral student and physical therapist at RIC and now a postdoctoral fellow at the NIH Clinical Center in Bethesda, MD.

In addition, recent advances in haptic feedback and gaming were included in the clinic study to enhance challenge and motivation with goal-oriented motor learning.

The pilot study showed the robotic device was an effective tool for passive stretching combined with active movement training and demonstrated improvements in joint biomechanical properties, motor control performance, balance, and mobility over baseline.

“We wanted to see if similar gains could be seen in a busy clinical setting with all its noise, distractions, and diverse patient diagnoses,” Sukal-Moulton said.

Participants in both studies had mild to moderate spastic CP. The 12 participants in the lab-based pilot study (average age, 7.8 years) received a one-hour therapy session three times a week for six weeks. All sessions employed the robotic device.

In the real-world study, 28 participants (average age, 8.2 years) were seen in 75-minute sessions twice a week for six weeks. Physical therapists who were not part of the core research team had significant input into the study design, resulting in the use of the robotic device for the first 30 minutes of each session, with the remaining 45 minutes devoted to individually tailored, functional movements.

The robotic training included 10-minute periods each of passive stretching, active-assisted movement, and either active or active-resisted movements. In the active-assist mode, participants played a video game controlled by their ankle movement, scaled to their ankle’s passive range of motion, and including a time delay before the device offered assistance. Utilizing the system’s touchscreen, therapists could add resistance to movements and change the game to require more or less force to move a cursor. Various gait, balance, and strengthening exercises were employed to maintain or extend the ROM gains achieved during robotic training.

“A robotic system can provide well-controlled instruction for children with CP, but it is unlikely that changes in range of motion alone can explain the clinical improvements we saw,” Sukal-Moulton said. “The critical component is more likely the large repetition of practicing a movement with an enhanced range, either in isolation or in a functional context.”

Eventually, the system might be used in the home environment, with initial set-up and periodic monitoring by a physical therapist.

“In the home, the number of days with device use might be increased for an additional boost, particularly when children have growth spurts,” Sukal-Moulton said. “This is in line with the current trend in physical therapy toward intensive bouts of interventions followed by the opportunity to do other things that are not therapy driven.”

CP specialist and surgeon Jon R. Davids, MD, said he looks forward to a comparison with other conventional therapies in a controlled trial.

“In addition, it is intriguing to anticipate the use of these devices in the home setting,” said Davids, a professor of orthopedic surgery at the University of California-Davis and at Shriners Hospitals for Children in Sacramento, CA, where he also is medical director of the Motion Analysis Laboratory. “Although the technology’s initial expense is significant, the potential increase in number of therapeutic sessions may offset that cost.”

Hank Black is a medical writer in Birmingham, AL.

Sources:

Wu YN, Hwang M, Ren Y, et al. Combined passive stretching and active movement rehabilitzation of lower-limb impairments in children with cerebral palsy using a portable robot. Neurorehabil Neural Repair 2011;25(4):378-385.

Sukal-Moulton T, Clancy, T, Zhang LQ, Gaebler-Spira D. Clinical application of a robotic ankle training program for cerebral palsy compared to the research laboratory application: Does it translate to practice? Arch Phys Med Rehabil 2014 May 1. [Epub ahead of print]