| Carpal tunnel syndrome (CTS) is a debilitating disease caused by median nerve entrapment at the wrist. Early detection is required to prevent permanent disability. Epidemiological studies have linked CTS to work practices common in many industries. The purpose of this study was to evaluate the use of vibration sensitivity testing and motor nerve conduction testing for detecting CTS in industry. Nerve conduction tests are used routinely in CTS diagnosis. Some researchers suggest vibrotactile sensation shows earlier changes in CTS.;Median motor nerve conduction and vibrotactile sensitivity were tested in 202 participants in four groups: controls, manufacturing plant workers with and without CTS symptoms, and physician-diagnosed CTS patients. Personal information was gathered through questionnaire. Ten participants were also tested with a multifrequency vibration sensitivity tester, designed by the investigator to measure thresholds at 10, 60, 100, 200 and 300 Hz.;Nerve conduction time differed significantly in the control, exposed and symptomatic groups. Vibration sensitivity threshold differed only in the diagnosed CTS group. There were no threshold differences among the other three groups.;Nerve conduction time in manufacturing plant employees was associated with weight and vitamin use. Vibration threshold was associated with number of years on the job. These factors did not alter the tests' ability to distinguish between employees with and without symptoms. Only 19.3% and 12.3% of the variation in these measurements was explained by variables examined in this study. Nerve conduction times and vibration thresholds were correlated; however, vibration thresholds were significantly elevated only in participants with nerve conduction times more than three standard deviations above the control mean. No subjective preference for either test was found. This study indicates median nerve conduction time is a better CTS indicator than vibration threshold at 120 Hz. The test is also acceptable to users.;Thresholds measured at 10, 60 and 100 Hz; and 200 and 300 Hz were strongly correlated. Thresholds at higher and lower frequencies were not correlated. This finding supports theories that two receptors are responsible for vibration perception. If one receptor is more sensitive to compression, vibration frequency may be an important parameter for future research. |
