Intertester reliability and diagnostic validity of the cervical flexion-rotation test

Objective: This article evaluates reliability and diagnostic validity of the cervical flexion-rotation test (FRT) to discriminate subjects with headache because of C1/2 dysfunction. In addition, this study evaluates agreement between experienced and inexperienced examiners. Methods: These were 2 single blind comparative measurement study designs. In study 1, 2 experienced blinded examiners evaluated the FRT in 10 asymptomatic controls, 20 Subjects with cervicogenic headache (CeH) where C1/2 was the primary dysfunctional level, and 10 subjects with CeH but without C1/2 as the primary dysfunctional level. In study 2, 2 inexperienced and 1 experienced blinded examiners evaluated the FRT in 12 subjects with CeH and 12 asymptomatic controls. Examiners were required to state whether the FRT was positive and also to determine range of rotation using a goniometer. An analysis of variance with planned orthogonal comparison, single measure intraclass correlation coefficient (2, 1), and Bland-Altman plot were used to analyze FRT range of rotation between the examiners. Sensitivity, specificity, and examiner agreement for test interpretation were analyzed using cross tabulation and kappa. Results: In study 1, sensitivity and specificity of the FRT was 90% and 88% with 92% agreement for experienced examiners (P < .001). Overall diagnostic accuracy was 89% (P < .001) and kappa = 0.85. In study 2, for inexperienced examiners, FRT mobility was significantly greater than for experienced examiners, but sensitivity, specificity, agreement, and kappa values were all within clinically acceptable levels. Conclusions: The FRT can be used accurately and reliably by inexperienced examiners and may be a useful aid in CeH evaluation.