Context/objective: Chronic pain is common in patients with spinal cord injury (SCI), for whom it negatively affects quality of life, and its treatment requires an integrated approach. To this end, lower limb functional electrical stimulation (FES) cycling holds promise.
Objective: To investigate pain reduction in a sample of patients with SCI by means of lower limb rehabilitation using FES cycling.
Design, setting and participants: Sixteen patients with incomplete and complete SCIs, attending the Neurorobotic Unit of our research institute and reporting pain at or below the level of their SCI were recruited to this exploratory study.
Interventions: Patients undertook two daily sessions of FES cycling, six times weekly, for 6 weeks.
Outcome measures: Pain outcomes were measured using the 0-10 numerical rating scale (NRS), the Multidimensional Pain Inventory for SCI (MPI-SCI), and the 36-Item Short Form Survey (SF-36). Finally, we assessed the features of dorsal laser-evoked potentials (LEPs) to objectively evaluate Aδ fiber pathways.
Results: All participants tolerated the intervention well, and completed the training without side effects. Statistically significant changes were found in pain-NRS, MPI-SCI, and SF-36 scores, and LEP amplitudes. Following treatment, we found that three patients experienced high pain relief (an NRS decrease of at least 80%), six individuals achieved moderate pain relief (an NRS decrease of about 30-70%), and five participants had mild pain relief (an NRS decrease of less than 30%).
Conclusion: Our preliminary results suggest that FES cycling training is capable of reducing the pain reported by patients with SCI, regardless of American Spinal Injury Association scoring, pain level, or the neurological level of injury. The neurophysiological mechanisms underlying such effects are likely to be both spinal and supraspinal.
Keywords: Cycling; Functional electric stimulation (FES); Laser-evoked potential (LEP); Pain; Spinal cord injury (SCI).