Effect Of Transcranial Direct Current Stimulation On Postural Control In Women With Premenstrual Syndrome

Postural control in women with Premenstrual Syndrome (PMS) decreases during the luteal phase and the rate of injury increases. In women with PMS, activation of the dorsolateral prefrontal cortex (DLPFC) is abnormally increased. Transcranial direct current stimulation (tDCS) can affect cerebral cortex function by changing cerebral blood flow and nerve excitability. The c-tDCS (cathodal-tDCS) over the L-DLPFC (left-DLPFC) can significantly reduce the COG sway velocity (deg/sec) when standing on one leg and improve the balance of women with PMS. PURPOSE: To investigate the acute effect of tDCS over the L-DLPFC on postural control and sensory organization in women with PMS. METHODS: A randomized, cross-over, double-blinded study included fifteen women (21 ± 2.3 years; 65 ± 4.75 m; 58.6 ± 6.12 kg; body mass index 21.4 ± 2.3 kg/m2; body fat 27.1 ± 6.13%, all right-handed). Participants were submitted to a-tDCS (anodal-tDCS), c-tDCS and sham-tDCS seven days before and three days after the start of the menstrual period, respectively. Sensory organization test (SOT) and unilateral stance (US) were assessed at pre- and post-tDCS. The differences were compared by two-way repeated measures ANOVA. RESULTS: The a-tDCS (76.4 ± 8.24) significantly reduced the ability to maintain balance through vestibular system compared with c-tDCS (81 ± 6.09, p = 0.018) and sham-tDCS (82.5 ± 7.51, p = 0.006), so the main effect of session was significantly different in VEST score (p = 0.01). Compared with a-tDCS (78.5 ± 4.24), c-tDCS (81.1 ± 4.56) could significantly improve the composite (CS) score of SOT (p = 0.005). Under the US-EO condition, there was no significant difference of the left leg. Meanwhile, the COG sway velocity of the right leg was significantly reduced after the c-tDCS (1.17 ± 0.363 vs. 0.947 ± 0.177, p = 0.015). Under the US-EC condition, the c-tDCS significantly reduced the COG sway velocity of the left leg (1.96 ± 0.615 vs. 1.73 ± 0.462, p = 0.023) at pre- and post-tDCS, and significantly reduced the COG sway velocity of the right leg (1.61 ± 0.361) compared with a-tDCS (1.95 ± 0.491, p = 0.009) and sham-tDCS (1.92 ± 0.621, p = 0.008). CONCLUSION: The c-tDCS can significantly improve static postural control in women with PMS and may enhance composite sensory by improving vestibular function.