Electoral pain threshold assessment
pain
In this trial, we assessed the pain threshold based on patients’ response to a gradual increased electrical stimulus (0.1 mA, pulse width 0.3 ms, impulse frequency 50 Hz) using a pain vision detection device (PS‐2100, Nipro Corporation, Osaka, Japan). During each assessment, a 1‐inch square electrode was placed either in the centered of the HZ skin or at the same area of contralateral skin. With the intensity of electrical stimulation increase, patients were asked to click a time‐count device. Three time point was measured based on previous studies (Shengai et al., 