Craniocervical Flexion Test Yields Decreased Deep Cervical Flexor Activity in Chronic Neck Pain Patients

• Number of participants: 20 recruited via advertisements in the local and university press

Neck Pain Group:

• Age: 32.2 +/- 9 years
• Gender: 6 female, 4 male
• Neck pain > 1 year

Asymptomatic Control Group:

• Age: 26.4 +/- 5.8 years
• Gender: 7 female, 3 male
• No current neck pain or history of orthopedic neck disorders

Exclusion Criteria:

• History of cervical spine surgery, neurologic signs, took part in a neck rehabilitation program within the past year or concurrent cervical treatment

• Both groups followed the same procedure.
• Each participant's nose and pharynx were anesthetized with Xylocane spray.
• To measure DCF activity, bipolar silver wire electrodes were inserted unilaterally through the nose and attached with a suction catheter to the oropharyngeal wall at the level of the uvula.
• To measure sternal head of sternocleidomastoid and anterior scalene activity, silver chloride surface electrodes were placed on the skin along each muscle belly.
• Participants were placed in supine hook lying with the head and neck in a midline position so that an imaginary line bisecting the neck ran parallel to the plinth.
• Prior to testing, participants were instructed in a gentle nodding technique to activate the DCFs and were allowed to practice reaching 5 target pressure intervals (22, 24, 26, 28, 30 mm HG).
• During testing, participants were instructed to perform craniocervical flexion with researcher cuing to eliminate muscular substitution.
• Visual feedback was given to maintain cervical pressure at each segment for 10 seconds, while EMG activity of the DCFs versus sternocleidomastoid and anterior scalene was recorded.
• Craniocervical flexion range of motion (ROM) was photographically recorded  laterally at head level for each of the 5 pressure segments.

• A Chatanooga Group Pressure Biofeedback Unit was used to measure craniocervical flexion
• A Power Shot 100 Digital Ixus was used to capture craniocervical flexion ROM
• Matlab 6.1 software was used for data calculation and analysis

• Root mean square EMG values for superficial and deep neck flexor muscles at each craniocervical flexion segment
• Percentage of full craniocervical flexion ROM

Asymptomatic Control Group:

• In both groups, a linear increase in DCF activation was recorded, but the amplitude was smaller for the neck pain group across each stage of the test.
• Sternocleiodmastoid and anterior scalene activity was greater at each stage of craniocervical flexion in the neck pain group.
• The ROM at each stage of the test was always significantly greater in the control group.

Our ConclusionsBoth overactive superficial cervical flexors and underactive deep cervical flexors are potential contributors to cervical pain and mobility impairments. Human movement professionals can use DCF training as an intervention for individuals with cervical dysfunction.Researchers' Conclusions

"This study provides data to support the proposal that decreased performance of the craniocervical flexion test is related to impaired performance of the deep cervical flexor muscles."

Caption: Cadaver Dissection reveiling the anterior side of the cervical spine with clear depiction of the deep neck flexors (longus colli and longus capitis)

Anterior Cervical Spine in Cadaveric Dissection - By Anatomist90 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19544659

Review & Commentary:

This study adds to a growing body of research on cervical spine dysfunction, muscle activity and assessment. The findings of this study suggest that cervical spine dysfunction is correlated with under-activity of the deep cervical flexors (DCF) (longus capitis, longus colli, rectus capitis anterior and rectus capitis lateralis ) during a craniocervical flexion test (CCFT) , as well as a decrease in cervical range of motion (ROM).

This study had several strengths, including:

• The CCFT  is both reliable and easily reproducible. Clinicians and human movement professionals can use this test to assess DCF  function relatively quickly and without expensive equipment.
• The study used well-defined inclusion and exclusion criteria to specifically test participants with idiopathic neck pain for more than 1 year.
• Electromyography (EMG) was recorded in a relatively direct and novel way, increasing the validity of the study and the CCFT . The use of goniometry to objectively measure range of motion (ROM) also increased reliability of the findings.

Weaknesses that should be noted prior to clinical integration of the findings include:

• Only 30-second rest intervals were allowed between test trials, which may have resulted in fatigue during subsequent trials.
• Surface electrodes were used to measure scalene and sternocleidomastoid activity; cross-talk may have contributed to signal intensity.
• The participants were relatively young, which may reduce generalizability to a population that is older and potentially more likely to complain of neck pain.

How This Study is Important:

As occupations and lifestyles become increasingly sedentary, chronic cervical pain will become more prevalent in healthy individuals (5). It is hypothesized that DCF  dysfunction is correlated with cervical dysfunction, and the CCFT  is a reliable assessment for DCF endurance. This study is one of the first to validate the CCFT  using a relatively direct measure of DCF activity; bipolar silver wire electrodes were inserted unilaterally through the nose and attached with a suction catheter to the oropharyngeal wall at the level of the uvula. The findings of this study support the validity of the CCFT  and imply a relationship between DCF  inhibition and cervical pain.

How the Findings Apply to Practice:

The findings from this study have several implications for practice. First, human movement professionals should consider integration of the CCFT  into their assessment protocols for cervical dysfunction. Second, DCF  inhibition is correlated with neck pain, implying that selective strengthening (DCF Activation ) may be recommended. Third, cervical pain and DCF  inhibition is moderately correlated with over-activity of the sternocleidomastoid and scalenes, implying release techniques may be appropriate. Last, there is a relationship between cervical dysfunction and loss of range of motion (ROM), implying that ROM should be assessed and addressed in this patient population.

How does it relate to Brookbush Institute Content?

The findings of this study support the Brookbush Institute's (BI) predictive model of upper body dysfunction (UBD) (as well as the Cervicothoracic Dysfunction Model in development) which characterizes the deep neck flexors (DNF) (longus colli, longus capitis, rectus capitis anterior, and rectus capitis lateralis) as "long/underactive." Individuals exhibiting dysfunction will likely present with excessive flexion (limited ROM) at the cervico-thoracic junction, cervical facet dysfunction related to hypertonicity of the levator scapulae , upper trapezius and sternocleidomastoid (SCM), and potentially elevation of the 1st rib due to hypertonicity in the scalene muscles. This presentation may perpetuate inhibition of the local stabilizers (DNFs ) and helps feed-forward compensatory over-activity of the superficial neck flexors, as described in the current study.

The following videos illustrate common assessment techniques and interventions used in analysis and treatment of cervical dysfunction:

Deep Cervical Flexor Endurance Test:

Deep Cervical Flexor Isolated Activation:

Deep Cervical Flexor Progression for Range of Motion:

Deep Cervical Flexor Activation and Progressions for Stabilization:

Bibliography:

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© 2018 Brent Brookbush

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