Effects of the menstrual cycle on vibrotactile sensitivity.

Abstract

Psychophysical thresholds for the detection of vibration delivered to the thenar eminence of the right hands of young males and females were measured every other day for 30–40 days. The frequency of the vibratory stimulus was either 15 or 250 Hz. The sinusoidal stimuli applied through a 3.0‐cm2 contractor were 700 ms in duration and had rise‐fall times of 25 ms. Stimulus amplitude was measured with a calibrated accelerometer mounted on the moving element of the vibrator. Data were plotted as a function of successive days in the menstrual cycle. Thresholds for the detection of the 15‐Hz stimulus did not significantly change over the menstrual cycle. Thresholds for detecting the 250‐Hz stimulus, on the other hand, varied significantly over the menstrual cycle. The 250‐Hz threshold became progressively lower as subjects approached the onset of menstruation. After the onset of menstruation, the 250‐Hz threshold gradually increased reaching a maximum value approximately 12 or 13 days later. Soon after the 12th...