Perceptual-motor performance during the menstrual cycle

Study I: Choice reaction times were measured in 12 normally menstruating women using a numerals-keys serial response task with three set sizes (two, four, and eight). Testing was carried out at four successive phases of the menstrual cycle corresponding with different states of neuroendocrine activity. They were, respectively: (i) 2nd day of flow; (ii) 4th day after cessation of flow (preovulation); (iii) 12th day after flow (postovulation); and (iv) 3rd day before next (estimated) flow. No consistent relationship between performance and phase of the cycle could be demonstrated. The only significant effect was an increase in reaction time with increasing set size. The study provides no support for the theory that variations in estrogen and progesterone levels may cause behaviorally relevant changes in central nervous system functioning. Study II: Four women suffering from premenstrual tension were examined thrice weekly on the same task for 4 consecutive weeks. Three hours prior to testing, a blood sample was drawn and assayed for estrogen, progesterone, and gonadotropin (LH). Performance on the serial choice response task bore no consistent relationship to blood levels of any of the three hormones. Performance before ovulation (as determined by peak LH level) did not differ significantly from that after ovulation. These results concur with those of Study I: there was no reliable relationship between hormonal status and performance.