A RANDOMIZED CONTROLLED TRIAL OF TIME CONTINGENT EXERCISES VERSUS SYMPTOM-CONTINGENT EXERCISES: EFFECTS ON SOMATOSENSORY CENTRAL PROCESSING

I. Moustafa¹, T. Shousha², V. Raigangar¹

Background: Modern pain neuroscience has advanced our understanding about pain. The structural pathology model does not adequately explain many of the clinical and experimental findings in subjects with chronic nonspecific neck pain and, more importantly, treatment guided by this paradigm fails to effectively treat many of these conditions. Increasing evidence reveals neoplastic changes within the central nervous system of people with chronic pain may appear to play a prominent role in the pathophysiology of these disorders. Neuroplasticity is an inherent ability of the brain and nervous system to develop and modify synaptic connections resulting in changes in structure, function and hierarchal organization within the nervous system. Accordingly the time contingent exercises as a clinical intervention aimed to modify the central processing of pain should be further evaluated to reveal the uncertainty about the efficacy of cognitive‐behavioral therapy.

Purpose: The purpose of this study is to compare time contingent exercises with symptom-contingent exercises for reducing pain and changing the central pain processing using somatosensory evoked potentials (SEPs) in subjects with chronic nonspecific neck pain.

Methods: Materials/Methods: 120 (70 female) participants with chronic nonspecific neck pain were randomly assigned to an experimental group (combined physical pain relief methods and sensorimotor control training using a time contingent approach) or a control group (combined physical pain relief methods and   sensorimotor control training using a symptom-contingent approach). Primary outcome measures included the neurophysiological parameters represented in amplitude of the individual SEP components: spinal N13, brainstem P14, parietal N20 and P27, and frontal N30 potentials .The secondary outcome measures included neck disability index and pain (pressure pain thresholds, numeric rating scale, and central sensitization inventory). Measures were assessed at 3 time intervals: baseline, 8 weeks, and 6-month follow-up.

Results: After 8 weeks, between-group analyses revealed statistically significant differences between the groups for the following measured variables: amplitudes of spinal N13, brainstem P14, parietal N20 and P27, frontal N30 potentials (p<0.001), NDI (p=0.001), pressure pain threshold (P= 0.003) , NRS (P=0.002)  central sensitization inventory  (P=0.04) and these differences were maintained at 6-month follow up.

Conclusion(s): Our findings suggest that time contingent exercises appears to be more effective than symptom-contingent exercises for changing somatosensory central processing and  improving pain, symptoms of central sensitization, and  disability.

Implications: Our findings emphasize the need for a shift toward a biopsychosocial focus (ie, cognition and perceptions underlying the pain problem), rather than maintaining a focus toward a structural pathology paradigm which have limited success in the treatment of many of these chronic conditions. Accordingly,  any clinical interventions aimed to modify the central processing of pain should address the cognitive and behavior aspect not only targeting peripheral mechanisms. The understanding of the underlying neurophysiological mechanism can eventually aid in the choice of the most indicated treatment for a chronic nonspecific neck pain.

Funding, acknowledgements: This project is self funded 

Keywords: Randomized controlled trial, Neck pain, somatosensory evoked potentials

Topic: Pain & pain management

Did this work require ethics approval? Yes

Institution: Cairo University

Committee: Research Ethics Committee-Faculty of Physical Therapy-Cairo University

Ethics number: CU-198746