Do Hormonal Fluctuations in Healthy Women Influence the Somatosensory Temporal Discrimination Threshold?

Preclinical studies and observations in human beings demonstrated that ovarian hormones exert complex, time-dependent effects on multiple brain regions, including those implicated in temporal sensory discrimination. The present study aims to investigate whether somatosensory temporal discrimination threshold (STDT) varies depending on the hormonal fluctuations in healthy women.

Twenty-six young women were enrolled, of whom six were taking contraceptive therapy. In each subject, we assessed STDT, both by the step-wise measurement (sSTDT) and the randomized one (rSTDT), at the three main phases of the ovarian cycle: menstrual phase, ovulation, and the luteal phase.

The Friedman test did not reveal statistically significant differences among the three time points for either sSTDT (χ² = 0.494, p = 0.781) or rSTDT (χ² = 0.838, p = 0.658). The Mann-Whitney U test for both sSTDT and rSTDT did not reveal statistically significant differences for each time point between subjects who were taking contraceptive therapy with those who were not (T1_st: U = 50, Z = -0.620, p = 0.573; T1_r: U = 58, Z = -0.126, p = 0.929; T2_st: U = 50, Z = -0.619, p = 0.536; T2_r: U = 56, Z = -0.248, p = 0.836; T3_st: U = 51, Z = -0.557, p = 0.614; T3_r: U = 52, Z = -0.502, p = 0.656).

Our study did not reveal any hormone-dependent variations in STDT across the phases of the ovarian cycle, supporting the notion that STDT is a stable neurophysiological parameter.