Abstract
Many quantitative sensory testing methods have been developed for assessing peripheral nerve functions, but these testing devices require electrode contact or direct attachment on the body surface. Thus, this is the major disadvantage when testing individuals with necrosis or infection. To solve this problem, we developed a new system for the measurement of sensory function using two kinds of air jet; steady flow and pulsatile flow. This system is an easy and objective method for detecting the perception threshold without contact material on the skin surface. The purpose of this study was to evaluate the accuracy and utility of the new system. By stimulating the skin surface with two kinds of air jet, the perception threshold is calculated from the pulsatile dynamic pressure [Pa] and the steady flow [mL/s]. This study was performed on 24 healthy volunteers (15 males and 9 females, aged 20-23 years), and the perception threshold was measured using the new system. The perception thresholds for the steady flow and the dynamic pressure were 51±20mL/s and 285±282Pa, respectively, in the right forearm. The steady flows in the right middle finger tip, the left forearm and the left middle finger tip were 58±33mL/s, 56±15mL/s and 62±26mL/s, respectively. Similarly, the dynamic pressures in the right middle finger tip, the left forearm and the left middle finger tip were 392±225Pa, 263±264Pa and 399±190Pa, respectively. However, the perception thresholds measured against the steady flow and the dynamic pressure did not show a significant correlation. Although many issues remain to be solved, the new device is effective for assessing peripheral nerve function by stimulating at an appropriate distance (4mm to 11mm) from the tip of the nozzle. Further studies in subjects with a wide age range and in patients are required to improve the sensitivity of measuring the perception threshold.
