RESUMO
ObjectiveTo investigate the effect of multi-target transcranial direct current stimulation (tDCS) and single-target tDCS on the performance of working memory-postural control dual-task in healthy adults, and to compare the regulatory effect of the two stimulation protocols. MethodsFrom November, 2020 to February, 2021, 19 healthy adults in Shanghai University of Sport were recruited and randomly accepted multi-target tDCS, single-target tDCS and sham stimulation with at least one week interval between any two stimulation protocols. The target areas of multi-target tDCS included left dorsal lateral prefrontal cortex (L-DLPFC) and bilateral primary motor cortex (M1), and single-tDCS only applied to L-DLPFC. Before and after stimulation, participants completed walking and standing balance tests under single task and dual-task conditions with the second task being a N-back task. The dual-task postural control performance, dual-task cost (DTC) and working memory performance were observed before and after stimulation. ResultsSignificant differences were observed among three stimulation protocols in the changes of stride variability (F = 3.792, P = 0.029), DTC of stride variability (F = 3.412, P = 0.040) and velocity of center of pressure (Vcop) (F = 3.815, P = 0.029). The stride variability (P = 0.047) and Vcop (P = 0.015) were significantly lower and the decrease in DTC of stride variability tended to be significant (P = 0.073) following multi-target tDCS, as compared to sham stimulation. Single-target tDCS significantly decreased the changes of stride variability (P = 0.011), DTC of stride variability (P = 0.014) and Vcop (P = 0.025), as compared to sham stimulation. Compared with single target tDCS, multi-target tDCS reduced the changes of the dual-task cost of the area of center of pressure (P = 0.035). Moreover, no significant difference was observed among the three stimulation protocols in the changes of each measure in the working memory test (P > 0.05). ConclusionBoth multi-target tDCS and single-target tDCS can improve the performance of working memory-postural control dual-task in healthy adults, and compared with single-target tDCS, multi-target tDCS has some advantages in regulating postural control.