Objective: To study the immediate sensorimotor neurophysiological effects of cervical spine manipulation using transcranial magnetic stimulation (TMS).
Design: Experimental design.
Setting: This study was carried out at the Human Neurophysiology Laboratory at the University of Auckland in Auckland, New Zealand.
Participants: Thirteen (13) subjects with a history of recurring neck stiffness and/or neck pain, but no acute symptoms at the time of the study were invited to participate in the study.
Intervention: Three (3) interventions were carried out in a randomised order: a control with no intervention, a passive head movement control condition, and a session of spinal manipulation of dysfunctional cervical joints.
Main Outcome Measures: Motor evoked potentials (MEP) and cortical silent periods (CSP) in the abductor pollicis brevis (APB) muscle of the dominant hand following transcranial magnetic stimulation (TMS) over the motor cortex.
Results: The major finding of this study was that the TMS-induced CSP measured in APB was significantly decreased for the first 20 minutes following spinal manipulation. No such changes were observed following either control condition, i.e. following no intervention or following passive head movement.
Conclusion: Spinal manipulation of dysfunctional cervical joints can lead to transient central neural plastic changes, as demonstrated by shortening of the TMS-induced CSP. This study suggests that cervical spine manipulation may alter sensorimotor integration. These findings may help to elucidate the mechanisms responsible for the effective relief of pain and restoration of functional ability documented following spinal manipulation treatment.