The effects of protocol and test situation on maximal vs. submaximal cervical motion: medicolegal implications

The objectives of this study were to examine the influence of the measurement protocol on the range and consistency of cervical motion (CM) in maximal vs. feigned limitation of CM, to explore some cognitive aspects of the feigning performance and to assess the effect of imagined pain vs. financial gain as a stimulus for the submaximal performance. The directions of flexion, extension, right and left rotation and right and left lateral flexion were measured in 26 normal subjects. Four protocols were compared: performance of CM with eyes open vs. eyes closed and testing at either a repetitive (within direction) or random (among directions) order. In each direction three measurements were recorded. Subjects were initially asked to move the head maximally, they were then presented with a vignette describing a fictitious accident involving the neck and were told to feign CM limitation in order to achieve unlawful compensation. In the third part, subjects were instructed to limit CM due to an imagined severe pain applying the repetitive order-eyes open paradigm only. Maximal CM paradigms were associated with significantly larger range ( p=0.0000) and higher consistency ( p=0.0000) compared the feigning paradigms. The eyes open-repetitive order protocol best separated between maximal and feigned performance. It was also indicated that the majority of subjects used the sensation of tension in the neck region as a cue for feigning while attempting to be as consistent as possible. Compared to feigning motivated by financial gain, limitation due to imagined pain resulted in significantly greater CM reductions and lesser consistency. The findings suggest that while feigning of motion impairment is probably based on somato-sensory input, the preferred CM testing protocol should consist of within direction repetitive movements with eyes open.