정상인과 Malingering 환자의 지각조절검사에서 검사-재검사의 의의

Background and Objectives: The clinical use of computerized dynamic posturography (CDP) in diagnosis and treatment of dizzy patient is based on its scoring system. We can assess balance disorder quantitatively with CDP and use it as a follow up test after treatment of dizziness. CDP can identify postural responses when there is suspected malingering, exaggeration of disability for compensation, or conversion disorder. So it can be used on medico-legal problem in work related claim. CDP findings of malingering show two patterns. First, there is poorer performance on sensory organization test (SOT) conditions 1, 2, 3 than on 4, 5, 6. Second, it may show excessive sway with non-overlapping tracing in MCT. To find another objective criteria for detection of malingering with CDP, we analyzed test-retest variability of SOT. Materials & Methods: Eighty healthy volunteers (forty malingerer, forty control) aged 23-31 (mean 28) were assessed by dynamic posturography. 3 cycles of SOT was done 2 weeks interval. In malingerer, the examinee was asked to pretend he or she was in the following situation. They experienced temporary unsteadiness and dizziness after job related injury. This resolved without tretment. however they are filling worker’s compensation claim for disability, and abnormal test result would strengthen their claim. Test-retest variability defined as difference maximal and minimal score of SOTs. Results: The obtained results were as follow 1) Mean scores of SOTs in malingerer lower than that of control in all 6 conditions 2) Except condition 6, test-retest variability of malingerer is significantly more than 10 compared to control (p<0.05) 3) test-retest variability of control is less than 10 in condition 1, 2, 3. 4) The most common abnormal finding of the malingerer is COG alignment (80%) Conclusion: If test-retest variability of SOT1-3 is over 10, we should strongly suspect malingering. If test-retest variability of SOT4-6 is over 10, we could suspect malingering. Thus it might be suggested that test-retest variability of SOT could detect malingering from true vertigo. (J Clinical Otolaryngol 2002;13:78-84)