Effect of Transcranial Direct Current Stimulation on Lower Extremity Muscle Strength, Quality of Life, and Functional Recovery in Individuals With Incomplete Spinal Cord Injury: A Randomized Controlled Study

Abstract

Background and objectives Muscle strength and function are essential facets of rehabilitation for incomplete spinal cord injury (iSCI) patients. Various methods are being used to improve these outcome measures, but no gold standard method exists. Transcranial direct current stimulation (tDCS) is a relatively inexpensive, portable, readily available, and easy-to-use modality. It has shown promising results in many psychiatric and neurological conditions like stroke, cerebral palsy, and depression, but its role in spinal cord injury (SCI) is relatively unexplored. The study's objectives are to investigate the effect of anodal tDCS on lower limb muscle strength, quality of Life (QoL), and function in individuals with iSCI. Methods A randomized single-blinded sham control parallel-group study was conducted at the Indian Spinal Injuries Centre in New Delhi, India. There were 32 iSCI participants (28 males and four females) with 23 traumatic and nine non-traumatic etiologies. Participants were randomly assigned to receive 40 minutes of 2 mA anodal or sham stimulation over the targeted motor cortex areas for five sessions per week over two weeks. The following outcome measures were measured at baseline after one and two weeks of the intervention: Lower Extremity Motor Score (LEMS), Spinal Cord Independence Measure (SCIM III), and WHO Quality of Life Bref (WHO QoL Bref). Results There was no significant difference at one week and two weeks of intervention for LEMS (p = 0.675, p = 0.978), SCIM III (p = 0.170, p = 0.133), WHO QoL Bref Domain 1 (p = 0.376, p = 0.282), Domain 2 (p = 0.728, p = 0.450), Domain 3 (p = 0.641, p = 0.993), Domain 4 (p = 0.294, p = 0.422), overall perception of QoL (p = 0.492, p = 1.000), and overall perception of their health (p = 0.300, p = 0.854) in the anodal and sham tDCS groups. Conclusion These primary findings suggest that anodal tDCS is ineffective in improving the QoL and motor and functional capabilities of individuals with iSCI. Further studies are necessary to determine whether it can be effective as a long-term rehabilitation strategy for the abovementioned population.

Keywords: lower extremity motor scores; motor capabilities; non-invasive brain stimulation; rehabilitation; spinal cord injury; transcranial direct current stimulation.