Alterations in cortical and cerebellar motor processing in subclinical neck pain patients following spinal manipulation

Objective: The purpose of this study was investigate whether there are alterations in cerebellar output in a subclinical neck pain (SCNP) group and whether spinal manipulation before motor sequence learning might restore the baseline functional relationship between the cerebellum and motor cortex.

Methods: Ten volunteers were tested with SCNP using transcranial magnetic stimulation before and after a combined intervention of spinal manipulation and motor sequence learning. In a separate experiment, we tested 10 healthy controls using the same measures before and after motor sequence learning. Our transcranial magnetic stimulation measurements included short-interval intracortical inhibition, long-interval intracortical inhibition, and cerebellar inhibition (CBI).

Results: The SCNP group showed a significant improvement in task performance as indicated by a 19% decrease in mean reaction time (P < .0001), which occurred concurrently with a decrease in CBI following the combined spinal manipulation and motor sequence learning intervention (F1,6 = 7.92, P < .05). The control group also showed an improvement in task performance as indicated by a 25% increase in reaction time (P < .001) with no changes to CBI.

Conclusions: Subclinical neck pain patients have altered CBI when compared with healthy controls, and spinal manipulation before a motor sequence learning task changes the CBI pattern to one similar to healthy controls.