Impact of Spinal Manipulation on Cortical Drive to Upper and Lower Limb Muscles
Written by Editor   
Thursday, January 19, 2017 02:45 PM

News Bite: Scientists used to believe spinal manipulation was purely a biomechanical treatment option for spinal pain conditions.  The growing basic science suggests that there may be more of a neurophysiological effect following spinal manipulation than previously realized.  This study show that spinal manipulation leads to changes in cortical excitability and that spinal manipulation may therefore be indicated for the patients who have lost tonus of their muscle and/or are recovering from muscle degrading dysfunctions such as stroke or orthopaedic operations and/or may also be of interest to sports performers.

 


Over the past 15 years there has been a growing number of human experiments conducted that have demonstrated there are central neural plastic effects from manual spinal manipulation.  Spinal manipulation is a conservative, low cost treatment option currently utilized for low back pain, neck pain and headaches. Clinical trials and systematic reviews have shown its usefulness for these conditions.  Scientists used to believe spinal manipulation was a biomechanical treatment option for spinal pain conditions. However, the growing basic science evidence suggests there may be more of a neurophysiological effect following spinal manipulation than previously realized.

The results of this study show that spinal manipulation leads to changes in cortical excitability, as measured by significantly larger MEPmax for TMS induced input-output curves for both an upper and lower limb muscle, and with larger amplitudes of MRCP component post manipulation. No changes in spinal measures were observed, and no changes were shown following the control condition. These results are consistent with previous findings that have suggested increases in strength following spinal manipulation were due to descending cortical drive and could not be explained by changes at the level of the spinal cord. Spinal manipulation may therefore be indicated for the patients who have lost tonus of their muscle and/or are recovering from muscle degrading dysfunctions such as stroke or orthopaedic operations and/or may also be of interest to sports performers.

This study investigates whether spinal manipulation leads to changes in motor control by measuring the recruitment pattern of motor units in both an upper and lower limb muscle and to see whether such changes may at least in part occur at the cortical level by recording movement related cortical potential (MRCP) amplitudes.

In experiment one, transcranial magnetic stimulation input-output (TMS I/O) curves for an upper limb muscle (abductor pollicus brevis; APB) were recorded, along with F waves before and after either spinal manipulation or a control intervention for the same subjects on two different days. During two separate days, lower limb TMS I/O curves and MRCPs were recorded from tibialis anterior muscle (TA) pre and post spinal manipulation. Dependent measures were compared with repeated measures analysis of variance, with p set at 0.05. Spinal manipulation resulted in a 54.5% increase in maximum motor evoked potential (MEPmax) for APB and a 44.6% increase in MEPmax for TA. 


Source: http://chiro.org/wordpress/2017/01/impact-of-spinal-manipulation-on-cortical-drive-to-upper-and-lower-limb-muscles/