The Effect Of Transcranial Alternating Current Stimulation On Attentional Function In The Post-stroke Cognitive Impairment Based On EEG

Background and ObjectiveAttention deficit is a serious complication of stroke.Attention improvement is the prerequisite for other cognitive deficit training.The inter-brain oscillation rhythm is the neural basis of attention function.Transcranial alternating current stimulation(tACS)of a specific frequency can entertain the brain oscillation and regulate the cortical network,which has a great prospect for the rehabilitation of attention deficit after stroke.The topic of this study is to explore the effect of transcranial alternating current stimulation on attentional function in patients with post-stroke cognitive impairment,and give the interpretation through electroencephalography.Methods22 cases included in the standard of cognitive dysfunction after stroke patients were randomly divided into 2 groups:active stimulation group and sham stimulation group.The stimulation with the theta frequency lasted 40 minutes for 7days,with two people in each group falling off.The stimulation electrode was positioned over the PO4 points according to the international 10-20 system and the reference electrode was placed in the right orbital region.Through the Montreal cognitive assessment scale(MoCA)and specific functional assessment,we assessed the patient before and after the treatment,with scores analyzed by SPSS23.0.In addition,the software,Matlab was use to analyze the electroencephalography covering power spectrum density,coherence,phase-locking value,phase lag index and weighted phase lag index.Results1.In the active group,MoCA scores before and after treatment showed significant difference(P<0.05),as well as Symbol-Digit Modalities Test and TMT(P<0.05).2.After treatment,the power spectral density in active stimulation group had a trend to increase in theta band(P>0.05)over PO4 while decrease in alpha band(P>0.05).Theta power spectral density in the left prefrontal cortex decreased significantly after treatment(P<0.05).Compared to the sham group,alpha power spectral density decreased significantly in the active group(P<0.05).3.After treatment,the alpha band phase synchronization of the parietal cortex and the left prefrontal cortex was increased in the active stimulation group(P>0.05).Conclusion:1.In this study,the performance of MOCA and attention function assessment test after treatment proved that the active stimulation combined with cognitive therapy improved the attention function of patients with cognitive dysfunction after stroke.2.TACS on the parietal cortex regulated the oscillation at theta frequency,and reduced the oscillation of alpha power there,improving the attention function of patients with post-stroke cognitive impairment.3.TACS modulated the parietal theta frequency thus increased alpha phase synchronization between posterior parietal and left prefrontal regions,improving attentional performance.