Research Review By Dr. Kent Stuber ©

Audio:

Download MP3

Date Posted:

February 2011

Study Title:

Effect of neck exercises on cervicogenic headache: a randomized controlled trial

Authors:

Ylinen J et al.

Author's Affiliations:

Department of Physical Medicine and Rehabilitation, Central Hospital of Central Finland

Publication Information:

Journal of Rehabilitation Medicine 2010; 42: 1-6.

Background Information:

Headaches of a cervical origin are common (cited by the authors as affecting 2.5% of the adult population and accounting for 15-20% of chronic and recurrent headaches). There is ongoing controversy regarding the classification and etiology of cervicogenic headaches, particularly as to whether it is a separate clinical entity, rather than a form of, tension type headache. Regardless, those with neck pain do more frequently experience headaches than those with symptoms in other anatomical areas. The authors reason that if neck exercise can be effective for chronic neck pain, then it may also prove useful for cervicogenic headaches; however there is minimal research to support this assertion. This study had three major aims with the first indicated as the primary aim of the study:
  1. “to determine whether exercise therapy relieves headache and arm pain associated with neck pain”;
  2. “to analyze whether the presence of headache indicates a more severe condition, with consequent negative effects on the outcome of exercise therapy in patients with chronic neck pain”; and
  3. “to analyze the dose-response relationship of the specific strength and endurance training regimens for the cervical muscles to reduce cervicogenic headache.”
This was to be done by comparing the efficacy of 3 different 12-month training programs.

Pertinent Results:

  • The groups did not differ in demographic data at baseline.
  • Strength Group: At 1 year, the strength group had a decrease in headache intensity VAS of 69%, significantly different from baseline and significantly different than the Control Group. Upper extremity pain was decreased by 58% - also significantly different than baseline and significantly different from the Control Group. Neck pain decreased by 69%, the most significant decrease in neck pain in all groups was for those subjects in the Strength Group with severe headaches.
  • Endurance Group: At 1 year the endurance group had a decrease in headache intensity (measured by VAS) of 58%, significantly different from baseline. Upper extremity pain was decreased by 70%, significantly different than baseline and significantly different from the Control Group, while neck pain decreased by 61%.
  • Control Group: At 1 year the control group had a decreased headache intensity of 37%, significantly different from baseline. Upper extremity pain decreased by 21%, significantly different than baseline, while neck pain decreased by 28%.
  • Energy expenditure training was negatively correlated with pain scores, accounting for 12% of the total variation predicted in the dose-analysis model.
  • Subjects with the highest pain scores initially showed the most benefit from the training programs, regardless of intervention groups as both training groups (strength and endurance) had significant decreases in headache intensity.
  • The dose analysis indicated that for every hour of training performed per week that a 0.6mm decrease in headache intensity on the VAS was observed.

Clinical Application & Conclusions:

The authors concluded that both strength and endurance exercises (combined with stretching) are effective for neck pain with associated headache and arm pain. Stretching alone was less effective than when combined with muscle endurance and strength training. They also noted that headache does not have a negative effect on the results of exercise therapy and does not hinder one from performing strength training which may be recommended for patients with severe headache associated with neck pain.

The results of this study are useful to clinicians as it provides evidence that may be helpful in recommending exercises for these patients, whether as in-clinic or at-home exercise programs. It also shows that the traditional model of stretching exercises only for patients with cervicogenic headache may be insufficient.

Study Methods:

This was a three arm examiner-blinded randomized controlled trial. 180 patients with long-standing neck pain were admitted into the study. They had to be currently employed female office workers between 25 and 53 years old with constant or frequent neck pain for at least 6 months. Exclusion criteria included:
  • disc prolapsed
  • stenosis
  • post-operative conditions
  • a history of severe trauma
  • instability
  • spasmodic torticollis
  • frequent migraine (more than 2x monthly)
  • peripheral nerve entrapment
  • Fibromyalgia
  • shoulder disease
  • inflammatory arthropathies
  • pregnancy
  • severe psychiatric illness
  • any other conditions that may limit their ability to participate in physical activity
A computer driven block randomization method was employed, to divide the patients into 3 groups – a strength training group, an endurance training group, and a control group. Outcome measurements were taken at baseline and after 12 months. Visual analogue scales and the Neck Disability Index were employed and subgroups of headache severity were established as per headache VAS scores into minor, moderate, and severe headache groups. Maximal neck isometric strength and ranges of motion were assessed, as was maximal oxygen uptake. Physical activity was assessed using a 4-week recall questionnaire and a training diary. Each group completed a 12-day institutional rehabilitation program and given a home exercise program.

The strength group completed five 45 minute sessions per week with every other session at a lower (50%) intensity. Exercises were performed as 1 set of 15 repetitions. Sessions finished with stretching and included elements of a neck school as well as 4 physical therapy sessions (consisting of mobilizations and massage).

The endurance training group completed five 45 minutes sessions per week with every other session at a lower (50%) intensity. Exercises were generally performed as 3 sets of 20 repetitions. Sessions finished with stretching and included elements of a neck school, as well as 4 physical therapy sessions (again consisting of mobilizations and massage).

The control group was advised to perform 30 minutes of aerobic activity 3 times per week as well as stretches at home for 20 minutes, but did not receive any treatments.

All groups were encouraged to exercise at home regularly 3 times per week at home. All of the groups completed their allocated programs for 12 months. An intention-to-treat analysis was employed as was a correlation analysis with a forced entry model, with the alpha level set at 0.05 for all statistical tests.

Study Strengths / Weaknesses:

The division of the study into three groups, two comparison groups and a control group are an important strength of this study. Having the control group complete a protocol that was part of the other two interventions was also of benefit.

The authors point to the small size of the subgroups employed as a possible weakness. They also comment that the headaches were not sub-typed (although subcategories in terms of headache intensity were created). It is also questionable as to how realistic the exercise programs described in this study might be for many clinicians and patients. To ask patients to complete neck exercises for 45 minutes, five times per week may not be feasible for many clinicians or achievable for many patients. In addition, the physical therapy treatments received by the two exercise groups were not well described (mainly massage and mobilizations but types and amounts not specified) and while the authors reasoned that they were intended to enable those with severe neck pain to perform their exercises, the control group did not receive any such treatments to allow them to perform their activities.

It is possible that the difference between the control group results and those of the treatment groups could be partially explained by this difference in physical therapy treatments received. To truly see the impact of the exercise interventions, the physical therapy treatments either should have been added to the control group or else should have been omitted completely. Finally, the inclusion criteria of this study were fairly limiting, and the external validity of results may be questionable.

Additional References:

  1. Vavrek D, Haas M, Peterson D. Physical examination and self-reported pain outcomes from a randomized trial on chronic cervicogenic headache. J Manipulative Physiol Ther 2010; 33(5): 338-48.
  2. Becker WJ. Cervicogenic headache: evidence that the neck is a pain generator. Headache 2010; 50(4): 699-705.
  3. Vincent MB. Cervicogenic headache: the neck is a generator: con. Headache. 2010; 50(4): 706-9.
  4. Vincent MB. Cervicogenic headache: a review comparison with migraine, tension-type headache, and whiplash. Curr Pain Headache Rep 2010; 14(3): 238-43.