Comparison of tactile sensitivity measured with a new digital esthesiometer (Beam Test) relative to Semmes-Weinstein monofilament analog esthesiometer.

The assessment of tactile sensitivity uses many tests, of which monofilaments are considered the best. The aim of this study was to develop a tactile sensitivity test, similar to the monofilament test, which eliminates the error risk related to manipulations by the observer, and to establish a correspondence scale. We studied 29 healthy subjects (18 women and 11 men) with a mean age of 27.8 years. The Semmes–Weinstein monofilament (SWM) analog esthesiometer and a digital beam esthesiometer (DBE) were used. We evaluated the tactile sensitivity threshold on the fingertip of each subject's dominant index using the SWM and the DBE. The DBE test consisted of applying the index against the tip of the beam. During a cycle of four elevations/depressions, the subject would press a button each time he/she felt pressure. The test was repeated three times. The screen displayed an average force value between 0 and 200 allowing the result to be expressed in grams (g). The minimum perceived force was 0.06656g (0.023, 0.166) on average with the SWM test and 0.51773g (0.4824, 0.8062) with the DBE test. Our results confirm the DBE test suppresses the observer's manipulations and that a SWM correspondence scale can be established. With the DBE test, the normal sensation ranged from 0.4824g to 0.757g and light touch decreased from 0.758g to 0.8062g. The threshold value of pathological tactile sensitivity was 0.8063g. The DBE test could therefore be used for preventive diagnosis of carpal tunnel syndrome in occupational medicine.