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Scratch Collapse Test Shows Low Accuracy after Subjects Mental Conditioning
Elif Ozyurekoglu, Scott Farner, MD, Madi El Haj, MD
CM Kleinert Institute for Hand and Microsurgery
2019-03-02
Presenter: Elif Ozyurekoglu
Affidavit:
The student completed this research as a science fair project. She contributed overall 75% of the work of the study.
Director Name: Michelle Palazzo
Author Category: Medical Student
Presentation Category: Clinical
Abstract Category: Hand
A manual muscle test of Applied Kinesiology, the Scratch Collapse test, was reported to be more sensitive than other diagnostic tests for carpal and cubital tunnel syndromes. While this test has been proposed to diagnose other nerve compressions, its possible subjectivity in terms of the examined patient's expectation has not been considered.
This study sought to find the effect of mental conditioning of a patient on the accuracy of the SCT. The hypothesis was that any mental conditioning of the patient would cause a change in the SCT diagnosis.
Fifty patients (37 females, 13 males) with an average age of 52 years, were invited to the study. 19 patients had both cubital and carpal tunnel syndrome, 13 patients had carpal tunnel syndrome only, 3 patients had cubital tunnel syndrome only, and 15 patients had no nerve compression. 400 tests were performed on 4 compression sites in both arms of the patients. A blinded examiner performed the SCT once regularly and once with a patient repeating a positive or negative word intently.
The sensitivity, specificity and accuracy of SCT for carpal tunnel syndrome was calculated as 89%, 80%, 85% respectively. These numbers fell to 63%, 78% ,70% respectively after the mental conditioning of the patient. Similarly for cubital tunnel syndrome these numbers fell from 89%, 84%, 86% to 67%, 75%, 72% respectively.
This study showed a consistent decrease in specificity, sensitivity, and accuracy for carpal and cubital tunnel testing after patients were mentally conditioned, suggesting the subjectivity of the SCT.
