P278 The EEG alpha response is affected by changes in sex hormone levels in two phases of menstrual cycle

Abstract

Objectives It is known that sex hormones affect the brain in women. However, there are not enough studies that explain the relationship between sex hormone fluctuations during menstrual cycle and brain waves. Our aim in this study is to show the effects of sex hormone fluctuations on the EEG alpha response in menstrual phase and follicular phase. Methods EEG recordings on resting state was performed in 11 healthy volunteer women in two different phases (menstrual and follicular). The alpha power values were analyzed by artifact-free 45 epochs lasting 2 s. Blood samples of volunteers were drawn simultaneously and estradiol, progesterone, FSH and LH were analyzed with electrochemiluminesence immunoassay method. The assessment of alpha power values and its relationship with hormone levels were performed in two phases of menstrual cycle. Results The highest difference between the mean power value in the menstrual phase (46.06) and the follicular phase (36.08) was obtained from the parietal region of the brain. At the same time, the lowest difference between the mean power value (41.06) in the menstrual phase and the follicular phase (39.37) was obtained from the occipital region of the brain. Estrodiol, progesterone, FSH, LH mean levels were 30.2 pg/ml; 0.17 ng/ml; 6.7 mIU/ml; 5.43 mIU/ml in the menstrual cycle and 123.9 pg/ml; 0.23 ng/ml; 7.3 mIU/ml; 17.12 mIU/ml in the follicular phase, respectively. Conclusion We found that increased estradiol levels in response to the elevation of LH levels in blood during follicular phase resulted in a decrease in the power of the alpha waves from the parietal region. Sex hormone fluctuations in menstrual cycle has minimal effect on the EEG alpha response in occipital region.