Temperature effects on vibrotactile sensitivity threshold measurements: implications for carpal tunnel screening tests

This study examines the effect of skin temperature on fingertip vibrotactile sensitivity measurements and the resulting implications for carpal tunnel syndrome screening tests. Twenty subjects (11 men, 9 women) were tested for fingertip vibrotactile thresholds using the method of limits at four different frequencies (31.5, 125, 250, and 500 Hz) and six temperature categories (17 degrees-20 degrees C, 20 degrees-23 degrees C, 23 degrees-26 degrees C, 26 degrees-29 degrees C, 29 degrees-32 degrees C, 32 degrees-35 degrees C). Vibrotactile sensitivity thresholds increased with decreasing fingertip skin temperature. Furthermore, the relationship was a function of vibration frequency. Higher frequencies were more affected by temperature than lower frequencies, with significant effects beginning at 29 degrees C. These temperature-related effects may lead to possible false positive results in screening for carpal tunnel syndrome or other neuropathies. To minimize potential temperature-induced misclassification errors during these screening tests, fingertip skin temperature should be recorded before measurement and probably maintained above 29 degrees C during the measurement.