['Prior neurophysiological studies on patients with premenstrual syndrome (PMS) have revealed sleep electroencephalographic alterations in both cycle phases. We report on a study evaluating saccadic eye movements in PMS patients.', 'Saccadic eye movements were examined in 21 women with and 21 women without PMS on two occasions in the midfollicular and late luteal phase, respectively. On each occasion, plasma levels for estradiol, progesterone, and neuroactive progesterone metabolites were determined.', 'PMS patients had decreased saccadic eye velocity (SEV) compared to control subjects. This finding was most evident in the luteal phase, whereas the difference between groups approached significance in the follicular phase. Saccade accuracy and saccade latency were not different between the two groups. Control subjects increased their SEV in the luteal phase compared to the follicular phase, whereas PMS patients did not. PMS patients rated themselves more sedated than control subjects on the testing days in both phases of the menstrual cycle. Plasma levels of gonadal hormones and neuroactive steroids did not differ between the study groups.'] Do patients with premenstrual syndrome have decreased saccadic eye velocity compared to control subjects?