Measurement of nociceptive mechanical sensitivity, thanks to a Randall-Selitto device. The latter makes it possible to exert a gradual mechanical force on a finger, caught between a flat surface and a point. The pressure supported by the subject is measured in grams, which makes it possible to determine his pain threshold. The objective is to study the integrity of the delta and C primary afferent fibers. The afferent fibers are sensory neurons whose role is to transmit sensory information to the central nervous system.