Altered Activation Pattern in Patients with Chronic Neck Pain

Background : Several studies on traumatic musculoskeletal pain syndromes such as Whiplash associated Disorder (WAD) have identified altered motor control of the cervical muscles during the performance of functional tasks. In chronic pain syndromes cervical muscle dysfunction appears to be a general sign. Postural asymmetries and movement dysfunction have been reported in patients with chronic pain. The objective of this study was to investigate if muscle tension of neck muscles is increased in patients with chronic neck pain. Thus this study compared the neck muscle activation patterns during static and dynamic tasks in patients with chronic neck pain of nontraumatic origin.

Methods: Electromyographic activity was recorded from the Sternocleidomastoid(SCM), Anterior Scalene(AS), Levator Scapulae(LS) and Upper Trapezius(UT) muscles. Percentage Maximum voluntary Isometric Contraction (MVIC) was calculated both during static tasks, which included shoulder abduction to 90° and hold, shrug and hold, craniocervical flexion and hold and a dynamic task.

Result: The results revealed elevated muscle activity in AS, LS and UT muscles during both static and dynamic tasks in patients with chronic neck pain of nontraumatic origin compared to controls.

CONCLUSION: In conclusion, patients with chronic neck pain of non-traumatic origin have increased muscle activity and hence increased muscle tension, which is responsible for postural asymmetries. Thus this increased muscle tension should be the focus of treatment.