Objectives: To evaluate the intra- and inter-examiner reliability of neck active joint position sense measurements in different head movements.
Methods: Participants had to reproduce actively a specific angle-target in all movements (flexion, right/left rotation, right/left side flexion) from two initial positions, sitting and standing by using a 3D ultrasound-based motion analysis device. Three tests were employed to assess intra-examiner reliability and two examiners used for the inter-examiner reliability. Absolute error (AE) and variable error (VE) indices were used to assess the repositioning accuracy. Intraclass correlation coefficient (I.C.C.(1,1)), standard error of measurement (S.E.M.), smallest detectable difference (S.D.D.) indices were calculated for the analysis of the results.
Results: Both AE and VE yielded poor to moderate I.C.C.s in any movement and position (-0.01 to 0.50 and 0.01-0.25, respectively). AE presented higher I.C.C.s estimates than the VE but the S.D.D.s were similar for both indices. Regarding the AE, the standing position yielded higher I.C.C. estimates (0.15-0.68) than the sitting position (-0.01 to 0.43) but the S.E.M. (1.2-3.0 degrees and 1.5-3.5 degrees, respectively) and S.D.D. values (123.3-191.8% and 139.9-203.8%, respectively) showed no specific trend in favour of any position. The VE reliability indices showed that standing position was more reliable with less error than sitting. The inter-examiner data showed similar results to the intra-examiner study.
Conclusions: The statistical analysis of the present experiments showed that the method employed for measuring cervical joint position sense is unreliable. However, it needs further research to identify the discriminatory power of these tests or if they are clinically unacceptable.