Abstract
Background: The premenstrual syndrome is a recurrent, variable cluster of trouble some ill-defined symptoms and signs that develop during the 10 days before the onset of menses and subside when menstruation occurs. There are studies in literature about the effect of psychological stress affecting audio visual reaction time (VRT). There are very few studies in literature about reaction time and premenstrual stress.

Aims and Objectives: The purpose of this study was to find out whether the premenstrual phase has any effect on human reaction time when compared with that of postmenstrual phase.

Materials and Methods: This study had been conducted in 100 healthy female volunteers in between 18 and 20 years age group. In this study, we had studied the time taken between applications of visual stimulus and auditory stimulus and response obtained and comparison of the response in female volunteer during premenstrual phase and postmenstrual phase. Subjects were presented with two types of stimuli; visual stimuli and auditory stimuli. Paired and unpaired t-test was used at appropriate places as a statistical test. The P < 0.05 was considered significant.

Result: A significant increase in weight and prolongation in auditory reaction time and VRT were observed during the premenstrual phase.

Conclusion: Increase in reaction time during premenstrual phase could be attributed to fluid and salt retention due to ovarian steroids leading to decrease in the processing capability of central nervous system and leads to prolongation of reaction time period.

Key words: Reaction Time; Premenstrual Stress; Visual Reaction Time; Auditory Reaction Time