Study suggests lower extremity functional electrical stimulation cycling can promote neurological recovery in chronic spinal cord injury patients


A study from the International Center for Spinal Cord Injury, published ahead-of-print, has found that long-term lower extremity functional electrical stimulation cycling, as part of a rehabilitation regimen, is associated with substantial improvements in individuals with chronic spinal cord injury. Improvements include neurological and functional gains, as well as enhanced physical health demonstrated by decreased fat, increased muscle mass and improved lipid profile. Prior to this study’s publication on 4 March 2013 in the Journal of Spinal Cord Medicine, the benefits of activity-based restorative therapy programmes, such as functional electrical stimulation cycling, were largely anecdotal.

According to a release, small electrical pulses are applied to paralysed muscles to stimulate movement during functional electrical stimulation cycling. In the case of functional electrical stimulation cycling, functional electrical stimulation pulses prompt the legs of an individual with spinal cord injury to cycle on an adapted stationary recumbent bicycle. The repetitive activity offers cardiovascular exercise similar to that which an able-bodied individual achieves through walking, but this new research shows that the results go far beyond basic health benefits.

“Exercise has not been commonly advocated for individuals with paralysis because of the assumption that it is of little benefit and it is challenging to exercise limbs that an individual cannot voluntarily move,” said John W McDonald, senior study author and director of the International Center for Spinal Cord Injury at the Kennedy Krieger Institute, USA. “However, we found that functional electrical stimulation cycling is a practical form of exercise that provides substantial benefits, including improved physical integrity, enhanced neurological and functional performance, increased muscle size and strength, reduced muscle spasticity and improved quality of life.”

Participants included in the study were 45 individuals diagnosed with chronic spinal cord injury, defined as paralysis continuing more than 16 months following injury. Twenty five patients with chronic spinal cord injury were assigned to the functional electrical stimulation cycling group at the Washington University Spinal Cord Injury Program. These patients were matched by age, gender, injury level/severity and duration of injury to 20 control patients who received no active physical therapy.

On average, patients did functional electrical stimulation cycling for 29.5 months, with an average distance of 10,466 complete cycles of the two pedals per week, the equivalent of taking 20,931 steps. In the retrospective analysis conducted by Kennedy Krieger researchers, improved motor function was observed in 80% of the functional electrical stimulation group, compared to only 45% of control subjects. Clinically important gains in neurological function were also observed in the functional electrical stimulation group such as response in pinprick sensation was observed in 56% of the functional electrical stimulation group compared with 25% of the control group, while 14 of the 25 functional electrical stimulation subjects showed response in light touch scores compared to six of the 20 controls.

Results also showed that functional electrical stimulation cycling enhanced muscle strength without increasing spasticity, a common side effect of paralysis that varies from mild muscle stiffness to severe, uncontrollable leg movements. The functional electrical stimulation group was found to be on fewer anti-spasticity medications with lower doses than the control group, suggesting that the lower level of spasticity observed in the functional electrical stimulation group was not due medication differences between the participants.

Functional electrical stimulation cycling was also associated with improvements in quality of life and correlated with overall improved health. Functional electrical stimulation and control groups showed no significant difference in total thigh volume; however, total thigh fat, measured by MRI, was 44.2% less in the functional electrical stimulation group than in the controls.

According to McDonald, this is a key finding because intramuscular fat is associated with glucose intolerance, a complication affecting nearly two-thirds of individuals with chronic spinal cord injury.

The results of this study support the hypothesis that activity-based rehabilitative strategies can play an important role in promoting physical integrity and functional recovery, even when implemented years after an injury, and provide rationale for a large prospective randomised clinical trial to evaluate the efficacy of activity-based restorative therapies using functional electrical stimulation in persons with chronic spinal cord stimulation.