| Carpal tunnel syndrome (CTS) often involves inflammation of the tendons or synovium transversing the wrist that control finger movement and grip. As tendonitis progresses, there is a constellation of CTS clinical signs, which do not clearly differentiate between tendonitis and CTS. At present, only nerve conduction latency across the wrist fulfills these criteria. The alternative of sensory testing (e.g., two-point discrimination, monofilament or vibratory threshold) lacks specificity; that is, sensory deficits can be attributed to other causes. Among the most popular in use today are the so-called provocative tests. These are based on the premise that stress on a damaged median nerve will increase the symptoms of pain or paresthesias or both and will increase the vibration threshold of the digits inervated by the median nerve.; More recently, a provocative technique has provided evidence of wrist level, median nerve entrapment before symptoms become unequivocal by more traditional procedures and has been reported to be specific for CTS over other forms of peripheral neuropathy. It was proposed to investigate ways of improving the efficiency of the initially reported provocative procedure to improve the sensitivity and specificity of CTS diagnosis. The provocative procedure takes advantage of the inflammatory processes residing within the carpal tunnel, which induce changes in median nerve transmission during sustained compression. An advantage of the provocative procedure is that the time-related changes it induces mimic, to some extent, the forces produced by repetitive motion. Hence, the assay not only looks at median nerve status but also provides a window into how the wrist is currently responding to ergonomic stressors and into the wrist's current inflammatory state.; This study examined the use of the vibrotactile threshold (VT) measurements in detecting the presence of CTS. The results of this study suggest the VT measurement for the subjects with symptoms and clinical test results that are consistent with CTS will improve the detection of CTS.; Logistic regression using forward and backward stepwise selection procedure and likelihood ratio criteria agreed with each other and yielded the same final model. Clinical Phalen's test rating, increase in the subjective rating of discomfort evaluated as 15-min provocation total discomfort compared to the rating without provocation, and difference between natural log VT of the middle finger and the little finger after 15-min provocation were identified as significant factors in both the forward and backward stepwise procedures to detect CTS from symptomatic hands. |
