P 258. Anodal tDCS and TENS for the treatment of chronic low back pain

Abstract

Introduction Persistent low back pain (LBP) is a leading cause of pain, suffering, productivity loss and disability. Yet, most therapies show only small effect sizes. A novel approach is the use of non-invasive brain stimulation in conjunction with traditional therapies to target ‘top down and bottom up’ mechanisms implicated in LBP. Objectives We investigated the effect of a combined transcranial direct current stimulation (tDCS) and transcutaneous electrical nerve stimulation (TENS) intervention on primary motor cortical (M1) representations, pain and sensorimotor function in persistent LBP. Materials and methods Using transcranial magnetic stimulation, the paraspinal muscles were mapped in sixteen individuals with persistent LBP and 16 healthy controls before and after one of four interventions: (1) active anodal tDCS/active TENS, (2) active anodal tDCS/sham TENS, (3) sham tDCS/active TENS or (4) sham tDCS/sham TENS. Each session lasted 30 min and was separated by at least 7 days. Measures of pain and sensorimotor function were made before and after each intervention. Results At baseline, individuals with LBP demonstrated representational abnormalities characterised by a single discrete area of peak corticomotor excitability (or ‘hotspot’) compared with two areas in healthy individuals. Combined anodal tDCS and TENS normalised M1 representations, reduced pain and improved sensorimotor function in persistent LBP. These improvements were greater than those observed with tDCS or TENS applied alone or sham. No change was observed in the cortical representation, or sensorimotor function, of healthy subjects following any intervention. Conclusions These data provide early evidence that improvements in pain and function may be related to normalization of M1 representations in persistent LBP. Furthermore, a combined anodal tDCS/TENS intervention may have potential as a therapeutic intervention for persistent LBP. Funding S. Schabrun is supported by a Clinical Research Fellowship (ID631612) and P. Hodges by a Senior Principal Research Fellowship (ID1002190), both from the National Health and Medical Research Council of Australia.