An investigation of stress and pain perception during manual therapy in asymptomatic subjects

Abstract

Stress perceived by the patient during the application of a manual therapy treatment technique may account for the reported findings of sympathoexcitation and hypoalgesia immediately after its application. This study investigated whether there was a difference in the level of perceived stress and pain before, during and after the application of a treatment condition (treatment, placebo or control technique), or whether the difference related to the time course of subject involvement in the study. Twenty-four asymptomatic subjects participated in a double-blind, placebo-controlled, within-subjects study in which stress was measured with a stress rating scale and a stress visual analogue scale. Pain experienced by the subject during the application of the treatment technique was measured with a visual analogue scale and modified McGill pain questionnaire. There was no effect of the treatment condition on perceived stress, but there was a reduction in stress levels over the time course of involvement in the experiment, as demonstrated by pre-application levels of stress. Pain was not produced by the treatment technique. This study demonstrated that stress and pain were not features of the lateral glide manipulation of the cervical spine in asymptomatic subjects. If the dorsal periaqueductal grey region is responsible for the initial effects of manual therapy, as has been previously suggested, then stress and pain do not appear to play a role in activating this system during the application of a manual therapy treatment technique in asymptomatic subjects.