The effect of high-frequency repetitive transcranial magnetic stimulation on cognitive function after stroke based on electroencephalogram nonlinear analysis

Abstract:

Objective To investigate the clinical effect of high frequency repetitive transcranial magnetic stimulation（rTMS） on cognitive function in patients with post-stroke cognitive impairment（PSCI） based on electroencephalogram（EEG） nonlinear analysis technology.Methods Forty patients with PSCI were randomly divided into the rTMS group and the control group，with 20 cases in each group. Both groups were given routine drugs and cognitive rehabilitation training. On this basis，the rTMS group were stimulated with 5 Hz rTMS to the dorsolateral prefrontal cortex（DLPFC） once a day for 20 min each time for 4 weeks. Before and 4 weeks after treatment，the cognitive function of the patients was assessed by Montreal cognitive assessment（MoCA），Stroop color-word test（SCWT），trail making test（TMT） and P300. At the same time，EEG signals were collected in the quiet state of closed eyes. The changes of functional connection in cognitive areas and other brain areas were observed through nonlinear analysis indexes including correlation dimension（D2） value and approximate entropy（ApEn） value.Results Compared with the control group，the MoCA score of rTMS group was significantly higher after 4 weeks of treatment（P<0.05）； in SCWT，the time consumption of card A，card B，the time consumption of interference and the correct number of interference decreased significantly（P<0.05）； in TMT，the time consumption of card A，card B and the amount of interference decreased significantly（P<0.05）； P300 latency was significantly shortened in rTMS group（P<0.05）； in rTMS group，D2 value and ApEn value increased significantly（P<0.05）. There was no significant difference in D2 value between rTMS group and control group in F4，O1 and F8 leads（P=0.074，0.179，0.120），there were significant differences in other leads（P<0.05），and there were significant differences in ApEn value between rTMS group and control group in FP1，FP2，F3，C4，P4，O2，F7 and T3 leads（P<0.05）.Conclusion High frequency rTMS treatment can effectively improve the cognitive function of patients with PSCI，affect the local neural circuit and compensate the cognitive function.