Improved Method for Non‐Invasively Monitoring Peripheral Neuropathy

Non‐invasive determination of peripheral neuropathy is crucial in diagnosing and monitoring a variety of diseases. Semmes‐Weinstein (SW) Monofilaments have been the standard in this area. Vibration perception threshold (VPT) instruments have been developed as an alternative method. Typically, VPT measurements at 120 Hz show a low correlation (r = 0.39) with SW. The sensitivity of touch receptors also varies with temperature. The purpose of this study was to determine if a novel VPT at 50 Hz, designed to stimulate the same receptors as the SW, provides a higher correlation, and determine if skin temperature improves the instrument's reliability and accuracy. 100 subjects, 18 to 88 years of age, were examined using the SW, novel VPT, and the Surface Temperature Scanner. Each subject was tested for nerve sensitivity and temperature on their fingertips. The correlation coefficient between SW and the VPT measurements was 0.88 (p=0.0000). Combining the VPT, subject's age and finger temperature resulted in a 72% accurate assignment of subjects into their correct clinical category for loss of sensation. Therefore, this study shows that the novel VPT provides measurements of peripheral neuropathy that have a stronger correlation with SW than current VPT instruments. This study also shows that by adding skin temperature, the novel VPT instrument would be more accurate and reliable in monitoring peripheral neuropathy.