Changes in neck motion and motor control and associations with neck pain in patients with non-specific neck pain

Abstract

Background: Neck pain is common in the general population with one year prevalence varying from 30% to 50%. Neck pain is the fourth leading cause of years lived with disability, which underlines the importance of research to identify effective prevention and treatment strategies based on knowledge of underlyingmechanisms of neck pain. Traditionally, physiotherapists have based their treatments of neck pain patients on functional tests and clinical findings. In the last 10 years studies show that neck pain is associated with several alterations in motor control and neck motion. Purpose: In a longitudinal study design we applied a comprehensive set of tests for motor control to investigate associations between motor control and neck pain. The aim was to investigate if motor control and neck motion changed following physiotherapy treatment and secondly, if changes in motor control were associated with reduced neck pain on an individual level. Methods: Subjects with non-specific neck pain (n= 71) participated in this observational study of neck pain patients in private physiotherapy practice. Neck flexibility, joint position error (JPE), head steadiness, trajectory movement control and postural sway were recorded at baseline before start of treatment, at 2 weeks, and 2 months. Numerical Pain Rating Scale was used tomeasure neck pain at the day of testing. To analyze within subjects effects in motor control and neck pain over time we used fixed effects linear regression analysis. Results:Neck flexibility and peak velocity increased after 2 weeks and 2 months compared to baseline. Neck pain patients improved their trajectory movement control and had less postural sway after 2 weeks and 2 months compared to baseline. Joint position error and conjunct motion did not change during the follow-up period. Changes in neck motion and motor control were largest from baseline to 2 weeks with small changes between 2 weeks and 2 months. Within individual changes were assessed with univariate regression analyses and showed that reduced neck pain was associated with twoneck motion and motor control variables; increased neck flexibility, and altered postural control. Conclusion(s): We found that only increased neck flexibility and altered postural control were associated with decreased neck pain after physiotherapy Treatment. Implications: For clinicians knowledge of the associations between neck pain and motor control on an individual level rather than group level is important. This study shows that few of the variables for motor control were associated with neck pain over a course of 2 months with treatment. While neck pain has been shown to be associated stiffening motion patterns, this study suggests that clinicians should focus treatment on interventions to increase neck flexibility and postural control since these variables were the only variables associated with neck pain reduction.