Vibrotactile threshold measurement for detecting neurotoxicity: reliability and determination of age- and height-standardized normative values.

Damage to the peripheral nervous system by neurotoxic agents can result in elevated sensory thresholds. In this study, the results of two studies in a program of validation of vibrotactile threshold test performance are presented. First, the test-retest reliability and time efficiency of two methods for generating vibrotactile thresholds were determined in a sample of subjects known to be at risk for peripheral neuropathy, 22 diabetics. Specifically, a forced-choice method was compared to a method-of-limits procedure. The method of limits was found to be as reliable as the forced-choice procedure and required less time to administer. The second study was undertaken to determine the magnitude of major effect modifiers on vibrotactile thresholds. Vibration thresholds were determined using a method-of-limits procedure in 131 blue-collar workers who were 29-76 y of age. Equations relating vibrotactile threshold estimated by the method-of-limits procedure to age and height are presented for the upper and lower extremities.