Neuroendocrinology and the ovulation cycle--advances and review

Fluctuations of perceptual asymmetry across time in women and men: effects related to the menstrual cycle

Women and men performed the same tachistoscopic chair identification task and free-vision face processing task during each of three test sessions. For women, the first and third sessions were performed during two successive periods of menstruation and the second session was performed during the intervening midluteal phase of the menstrual cycle. For men, the three test sessions were presented at 2-week intervals. For the chair identification task, there was no visual field (hemispheric) asymmetry for men during any of the three test sessions. For women, there was a right visual field (left-hemisphere) advantage during the second (midluteal) test session, but not during the first and third (menstrual) sessions. For the free-vision face processing task, there was a robust left-side (right-hemisphere) bias during all test sessions for both women and men and no effect of test session for either gender. Results for the nonlateralized chair identification task are consistent with the hypothesis that, in women, the left hemisphere is more activated during the midluteal phase of the menstrual cycle relative to the menstrual phase. Results for the lateralized face processing task suggest that hemispheric dominance for specific aspects of information processing are less likely to show such phase-related effects.

[Ovulatory period and epileptic crisis]

We prospectively follow up 80 mentally healthy women at menacme age, with chronic epilepsy and had had least one seizure in the month preceding the study. We selected 59 patients from whom we were able to observe at least three regular menstrual cycles with seizures. We defined regular, irregular cycle, perimenstrual and ovulation period. According to our concepts we have got 19, 30 and 6 patients with respectively severe, moderate and mild exacerbation of perimenstrual seizures. Using our definitions 6, 20 and 17 patients showed severe, moderate and mild accentuation of seizures during ovulation, while 15 patients showed no ovulatory accentuation. Our attention was drawn to the great number of perimenstrual and ovulatory exacerbation of seizures, according to our criteria. From 55 patients with perimenstrual accentuation of seizures 44 (74.54%) showed exacerbation during the ovulatory period. In our opinion, these data speak out in favor of the hormonal theory to explain these occurrences. We discuss these data based on the available literature. We think the estrogen peak is probably the main cause of the increased frequency of epileptic seizures during the ovulation period. New studies, documenting objectively the ovulation and seizures are mandatory to clarify the relationship of these aspects of the female endocrine reproductive physiology in epileptics.

Premenstrual seizure increase: influence of age, duration of disease, seizure frequency, previous complaint of perimenstrual accentuation, EEG and CT scan findings

We selected prospectively 80 mentally healthy women at menacme age, with chronic epilepsy and at least one seizure in the month preceding this study. They underwent four EEGs weekly. CT scan of the skull was done in 57 patients (71.25%). Seven patients were excluded because they had no seizures or menses. We registered 5630 seizures during 579 regular menstrual cycles over a 30 month period.

RESULTS

there was a higher incidence of seizures in the premenstrual period (p less than 0.001); age did not influence the distribution of seizures during the menstrual cycle in the group studied; patients with 11 or more years of disease showed more accentuation of premenstrual seizures than patients with 10 or less years of disease; there was no relation between the patients frequency of seizures and the occurrence of premenstrual seizures; the patients impression of the incidence of seizures not related to menstruation was not confirmed; patients with abnormal skull CT scans had more accentuation of premenstrual seizures than patients with normal exams; patients with abnormal EEGs had more premenstrual seizures than patients with normal exams. Our findings suggest that the female sexual hormones alter cerebral excitability when there is an underlying structural pathology shown by CT scan or an electrical cerebral dysfunction revealed by EEG.

Visual cerebral lateralization over phases of the menstrual cycle: a preliminary investigation

This study investigated whether visual cerebral asymmetries would change in phase with hormonal variations during the menstrual cycle. Lexical decision and line orientation tasks were administered during follicular, luteal, and menstrual phases of each woman's cycle. These tasks were also administered to a reference group of male subjects. Signal detection analyses indicated an unvarying RVF advantage in word/nonword discriminability (d') throughout the menstrual cycle, but a phase-dependent shift in left hemisphere response criterion (log beta). Gender differences were present for discriminability of line orientation, and female performance on this task varied over the cycle. The results imply that the neural systems subserving some cognitive functions are sensitive to fluctuations in gonadal steroids and suggest a hormonal basis for gender differences in some visual-spatial functions.