Cortical excitability and multifidus activation responses to transcranial direct current stimulation in patients with chronic low back pain during remission

Abstract

Evidence indicates that patients with chronic low back pain (CLBP) have lumbar multifidus muscle (LM) activation deficit which might be caused by changes in cortical excitability. Anodal transcranial direct current stimulation (a-tDCS) can be used to restore cortical excitability. This study aimed to (1) determine the immediate effects of a-tDCS on the cortical excitability and LM activation and (2) explore the relationship between cortical excitability and LM activation. Thirteen participants with CLBP during remission and 11 healthy participants were recruited. Cortical excitability (peak-to-peak motor evoked potential amplitude; P2P and cortical silent period; CSP) and LM activation were measured at pre- and post-intervention. We found significant difference (P < 0.05) in P2P between groups. However, no significant differences (P > 0.05) in P2P, CSP and LM activation were found between pre- and post-intervention in CLBP. The CLBP group demonstrated significant correlation (P = 0.05) between P2P and LM activation. Although our finding demonstrates change in P2P in the CLBP group, one-session of a-tDCS cannot induce changes in cortical excitability and LM activation. However, moderate to strong correlation between P2P and LM activation suggests the involvement of cortical level in LM activation deficit. Therefore, non-significant changes could have been due to inadequate dose of a-tDCS.

Validity and Reliability of an iPhone® Clinometer Application for Assessment of Joint Repositioning Error in Patients with Non-Specific Chronic Low Back Pain

“…According to recent comprehensive reviews, patients with NSLBP have much worse lumbopelvic proprioceptive acuity than people without symptoms (4,8) . Individuals with NSCLBP have been shown to have both functional (e.g., disrupted neuromuscular coordination between the deep and superficial back muscles) and structural (e.g., muscle atrophy and fat infiltration) alterations in the trunk muscles (9) . These modifications cause impairments in tactile selective acuity and proprioception, which impair motor function, upset segmental spinal stability, and eventually cause greater pain and articular injury (10) .…”