Handheld Isobaric Aesthesiometer for Measuring Two-point Discrimination

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 to 500g) in the normal aesthesiometer with rigid prongs which approximately follows the secondorder 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