EFFECTS OF TOTAL ESTROGEN CONCENTRATION AND MENSTRUAL-CYCLE PHASE ON REACTION-TIME PERFORMANCE

This study investigated reaction time performance during the pre-menstrual-menstrual phase of the cycle and the relationship of plasma oestrogen concentration to react ion time. The study included 18 young women using oral contraceptives and 18 young women normally cyclic. Testing once per week throughout two menstrual cycles consisted of simple, complex and choice reaction time tests and blood sampling for total plasma oestrogen level as determined by radioimmunoassay. Mean Phase 1 (five days pre- and postmenses) and Phase 2 (the remaining days of the menstrual cycle)reaction time scores for each subject on each task were used in several 2x2 variance analyses with repeated measures on the last factor. Oestrogen data were analyzed identically for all subjects. No significant differences in performance were found on the simple and complex tasks. Reaction time was significantly longer in Phase 1 than in Phase 2 for those normally cyclic on the choice task but not in those using oral contraceptives. Total oestrogen levels were significantly lower in those using oral contraceptives than in the normally cyclic subjects. A direct relationship between oestrogen concentration and reaction time performance could not be supported by the findings. © 1979 Taylor & Francis Group, LLC.