Effects of Online Transcranial Alternating Current Stimulation Over the Parietal Cortex and Supplementary Motor Area on Bimanual Coordination in Elderly Women

Objectives:

 Considering the negative effects of aging on bimanual motor skills, attention has been drawn to various non-invasive brain stimulation methods for the improvement of these skills. This study aimed to investigate the effects of online transcranial alternating current stimulation (tACS) over the right posterior parietal cortex (P4) and supplementary motor area (SMA) on bimanual coordination in elderly women. 

Methods :

This is a quasi-experimental study. The study population includes all healthy elderly women aged 60-75 years in Tehran, Iran, of whom 31 were selected using a convenience sampling method and were subjected to tACS over P4, tACS over SMA, and sham tACS along with performing the Purdue pegboard task (4 trials) in three sessions with a one-week interval.  Data were analyzed byby 3(condition)*4(trials) ANOVA with repeated measures.

Results:

 The results of ANOVA showed that only the main effect of trial was statistically significant (P<0.001); The main effect of condition and the interaction effect of condition and trial were not significant (P>0.05). Therefore, although bimanual coordination increased significantly in all three conditions in different trials, there was no significant difference in bimanual coordination among different conditions.

Conclusion :

The online tACS over P4 or SMA has no short-term effect on the bimanual coordination of elderly women. Further studies are recommended to assess the long-term effects of tACS in other areas of the cerebral cortex using different protocols.