| Research Review by Dr. Michael Haneline© | | Date: | Oct. 2008 | | Study Title: | Intertester reliability and diagnostic validity of the cervical flexion-rotation test | | Authors: | Hall J et al.
Authors’ Affiliations: School of Physiotherapy, Curtin University of Technology, Australia | | Publication Information: | Journal of Manipulative & Physiological Therapeutics 2008; 31:293-300. | | Summary: | Cervicogenic headache (CeH) is a sometimes debilitating condition that accounts for 15% to 20% of all headaches. The International Headache Society has defined CeH as “head pain, referred from a source in the neck that may arise from a variety of upper cervical spine structures.”1 Several researchers have pointed to upper cervical dysfunction, C1-2 in particular, as the underlying cause of CeH. Accordingly, the condition can usually be treated effectively by manual methods.
There is some evidence that manual examination methods (e.g., motion palpation and pain provocation) are capable of identifying C1-2 dysfunction. One such method is the cervical flexion-rotation test (FRT), which is carried out by placing the supine patient’s neck in flexion while passively rotating the head. Maximum C1-2 passive ROM is determined either by the patient reporting the onset of pain or by the examiner meeting firm resistance. The basis of the test is that cervical motion is limited to the C1-2 level when the head is held in full flexion. Thus, any rotation that is detected during the test is primarily attributable to motion at C1-2.
A positive FRT, which indicates C1-2 dysfunction, occurs when rotation to one side is obviously limited as compared with the other side. Normal rotational passive range-of-motion with the cervical spine fully flexed has been reported to be 44o.
This article actually reported on 2 separate studies that were carried out at different times.
The first study was an examiner reliability and validity study that involved 2 experienced examiners. Another manual therapist evaluated the CeH subjects prior to FRT to determine which cervical segment was the primary dysfunctional level. The sample was divided into 3 groups, as follows: - CeH with C1-2 dysfunction
- CeH with dysfunction at a cervical level other than C1-2
- asymptomatic
The second study also examined reliability and validity using 3 examiners (2 were inexperienced and 1 was experienced). There were only 2 groups this time, as follows: - CeH
- asymptomatic
Pertinent results of study 1 include:
Average rotation ranges were: - asymptomatic subjects, 44° to the left and 43° to the right (this is in agreement with previous literature on this test)
- CeH subjects where C1-2 was not the primary dysfunctional level, 42° to the left and left and 40° to the right
- CeH subjects where C1-2 was the primary dysfunctional level, the range toward the most restricted side was 30°
- Interexaminer reliability was reported to be very high for the FRT (Intraclass Correlation Coefficient [ICC] = 0.93; CI: 0.87 to 0.96)
- The difference between these groups was statistically significant. However, the difference was only 4° between the asymptomatic group and the group with CeH but without C1-2 as the primary dysfunctional level.
Several factors pointed to excellent agreement between the examiners in this study: - examiners agreed on their interpretation of the FRT 92% of the time
- points on a Bland-Altman plot comparing the examiners were evenly distributed and within required limits
- the reported κ value was 0.85
Validity of the FRT was also supported because sensitivity and specificity were reasonably high: - sensitivity (the ability of a test to identify those who have the condition) was 90%
- specificity (the ability of a test to identify those who do not have the condition) was 88%
Likelihood ratios (LR), which are derived from sensitivity and specificity values, pointed to a helpful test: - positive LR (the increase in odds favoring the condition, given a positive test) ranged from 6 to 9
- negative LR (the change in odds favoring the condition, given a negative test) ranged from 0.11 to 0.12
Pertinent results of study 2: - Examiner reliability for the FRT was also high in study 2: for interexaminer reliability, ICC values ranged from 0.76 to 0.84; for intraexaminer reliability, ICC values ranged from 0.84 to 0.89
- Inexperienced examiners reported a significantly larger range of C1-2 motion than the experienced examiner, but there was no significant difference between the 2 inexperienced examiners.
- The experienced examiner agreed with the inexperienced examiners 88% and 83% of the time.
- κ values were 0.75 and 0.67, which reflected good agreement between these examiners.
Validity was supported because: - sensitivity overall was 90% for the experienced and 83% for the inexperienced examiners
- specificity overall was 85% for the experienced and 83% for the inexperienced examiners
The LRs in study 2 also pointed to a helpful test: - positive LR ranged from 5 to 6
- negative LR ranged from 0.12 to 0.2
| | Conclusions & Practical Application: | The authors suggested that in order for a clinical test to be considered reliable, κ values should be above 0.4. All calculated κ values in this study were well above this threshold, pointing to an acceptable level of reliability, even among inexperienced examiners.
In addition to being a reliable test, diagnostic accuracy, sensitivity, and specificity of the FRT were also very high. While experienced examiners fared better than the inexperienced, reporting a greater range for the FRT than experienced examiners, sensitivity, specificity, and agreement were still within clinically acceptable levels.
FRT measurements for asymptomatic subjects were 43° to the right and 44° to the left, which is consistent with measurements reported in other studies.2,3
In subjects with CeH who had C1/2 dysfunction, there was a reduction of FRT mobility by 14° as compared to asymptomatic subjects or those with CeH but without C1/2 dysfunction. Again, these findings are congruent with reports by other researchers. It was suggested that a difference of this magnitude would be easily detectable in the clinical setting.
Based on the high level of examiner agreement found in this study, both in experienced as well as inexperienced examiners, the authors suggested that the FRT is a useful clinical measure which can facilitate the differential diagnosis of CeH.
Additional References: - The International classification of headache disorders: 2nd edition. Cephalalgia 2004; 24(Suppl 1):9-160.
- Hall T, Robinson K. The flexion-rotation test and active cervical mobility–a comparative measurement study in cervicogenic headache. Man Ther 2004; 9:197-202.
- Amiri M, Jull G, Bullock-Saxton J. Measuring range of active cervical rotation in a position of full head flexion using the 3D Fastrak measurement system: an intra-tester reliability study. Man Ther 2003; 8:176-9.
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