TY - JOUR
T1 - Cervical circumduction in normal subjects
T2 - A study of maximal versus feigned effort
AU - Dvir, Z.
AU - Prushansky, T.
PY - 2001
Y1 - 2001
N2 - The feasibility of using the coefficient of variation in conjunction with motion parameters derived from head circumduction to obtain a compact criterion for differentiating maximal from feigned cervical motion was evaluated. Twenty-five healthy subjects were measured twice during a period of 3 weeks using an ultrasonography-based motion analysis system. Subjects were asked to produce maximal motion of the spine as well as to feign limitation. Extracted from the displayed traces of head circumduction, the angular values of the primary motions of flexion, extension, right and left lateral flexion, as well as their additive score (AS) were determined. No test-retest differences were indicated. The average range of motion (ROM) was significantly smaller and the coefficient of variation of the ROM was significantly larger in the feigned compared with the maximal performance in both tests. However, tolerance interval analysis indicated that the coefficient of variation could not effectively separate between the effort levels, being particularly deficient with respect to AS. In addition, a differential sensitivity in identifying false-negative cases as a function of the movement paradigm was revealed. This study indicates that in healthy subjects, the use of a complex cervical movement such as circumduction cannot serve for differentiating between maximal and feigned performance using the coefficient of variation. The results may also point out the existence of a mechanism for adjusting proportional reductions among the primary cervical motions that result in excellent repeatability even in feigned efforts.
AB - The feasibility of using the coefficient of variation in conjunction with motion parameters derived from head circumduction to obtain a compact criterion for differentiating maximal from feigned cervical motion was evaluated. Twenty-five healthy subjects were measured twice during a period of 3 weeks using an ultrasonography-based motion analysis system. Subjects were asked to produce maximal motion of the spine as well as to feign limitation. Extracted from the displayed traces of head circumduction, the angular values of the primary motions of flexion, extension, right and left lateral flexion, as well as their additive score (AS) were determined. No test-retest differences were indicated. The average range of motion (ROM) was significantly smaller and the coefficient of variation of the ROM was significantly larger in the feigned compared with the maximal performance in both tests. However, tolerance interval analysis indicated that the coefficient of variation could not effectively separate between the effort levels, being particularly deficient with respect to AS. In addition, a differential sensitivity in identifying false-negative cases as a function of the movement paradigm was revealed. This study indicates that in healthy subjects, the use of a complex cervical movement such as circumduction cannot serve for differentiating between maximal and feigned performance using the coefficient of variation. The results may also point out the existence of a mechanism for adjusting proportional reductions among the primary cervical motions that result in excellent repeatability even in feigned efforts.
KW - Cervical spine
KW - Differentiation
KW - Effort
KW - Motion
UR - http://www.scopus.com/inward/record.url?scp=0035208663&partnerID=8YFLogxK
U2 - 10.1097/00002517-200112000-00002
DO - 10.1097/00002517-200112000-00002
M3 - מאמר
AN - SCOPUS:0035208663
VL - 14
SP - 472
EP - 478
JO - Journal of Spinal Disorders
JF - Journal of Spinal Disorders
SN - 0895-0385
IS - 6
ER -