Handheld isobaric aesthesiometer for measuring two-point discrimination

Abstract

Two Point Discrimination test is notorious for their unexplained variations within subjects, between subjects, and between studies. This paper presents a systematic study of these variations and proposes a simple design to control the variations, thereby improving the TPD measurement accuracies. In the proposed Isobaric Aesthesiometer, monofilaments are used replacing the rigid prongs in a handheld aesthesiometer. Compared to the force variation (0–500g) in the normal aesthesiometer with rigid prongs which approximately follows the second-order system, the force variations in the isobaric aesthesiometer is found to be nearly constant within a tight tolerance. Although the proposed handheld instrument could be used in controlling forces applied in a TPD measurement, unless a standard protocol is developed for measuring the TPD, the variation cannot be controlled even with this device.