| Objective: To clarify the effect of repetitive Transcranial Magnetic Stimulation(rTMS)on improving cognitive function in patients with Alzheimer’s Disease(AD)and influence on the spontaneous brain activity and functional connectivities.Methods: A total of 29 patients who met the diagnostic criteria of "probable AD" were recruited from the community hospital of Xicheng in Nanchong city,and were randomly divided into an experimental group(14 patients)and a control group(15 patients).Patients in the experimental group received 20 Hz high-frequency rTMS treatment over the left dorsolateral prefrontal cortex(DLPFC)with the stimulation intensity of 90% rest motor threshold(RMT),and 25 s of stimulation interval.The stimulation parameters of the control group were identical with the experimental group,but with a sham stimulation coil that could not produce real and effective stimulation to the patients.Patients in both groups received 20 days of rTMS treatment.Comparisons of the cognitive function score and Amplitude of Low Frequency Fluctuation(ALFF),functional connnectivity between before and after treatment in each group and the two groups after treatment were all performed.Results: No significant difference was observed in age,gender,education and scores of cognitive function between the experimental group and the control group in baseline.After rTMS treatment the following changes and differences were detected:(1)compared to pre-treatment,patients in the experimental group had great changing in Mini-mental State Examination(MMSE)(P= 0.015),delayed recall scores of Auditory Verb Learn test-Huashan version(AVLT-H)(N5)(P < 0.0001),recognition scores(N7)(P= 0.006)and Boston Naming Test(BNT).The Sham group found significant improvements in MMSE(P<0.0001),N5(P<0.0001),Animal Fluency Test(AFT)(P= 0.042),and BNT(P= 0.004)scores.After treatment,there were significant differences in MMSE(P= 0.025)and N7(P= 0.046)between the two groups.(2)ALFF analysis showed that the spontaneous neural activity in the experimental group was significantly increased in the bilateral posterior cingulate cortex(PCC),bilateral precuneus and middle cingulate cortex(P<0.05),and significantly decreased in the bilateral parietal lobe and bilateral occipital lobe(P<0.05).In the control group,ALFF values in the right insular lobe,right superior temporal gyrus and right superior marginal gyrus were significantly decreased(P < 0.05).Moreover,there was a significant positive correlation between the ALFF change of the PCC and the change of N5 score in the rTMS group after treatment(r= 0.553,P = 0.04).(3)The functional connectivities between the PCC and right supramarginal gyrus(R＿SMG),the left occipitotemporal cortex(L＿OTC)and R＿SMG,the left hippocampus(L＿HIP)and left frontoinsular cortex(L＿FIC)were significantly increased after rTMS treatment in the experimental group.Besides,the functional connectivities in experimental patients were significantly stronger than control patients between the R＿SMG and L＿OTC,the PCC and Left Middle Occipital Gyrus,L＿MOG),the L＿HIP and L＿FIC,R＿SMG,L＿MOG,the L＿ITG,and L＿OTC(P<0.05).No significant increased functional connectivity was observed in control group..Conclusion: High-frequency rTMS could improve the cognitive function of AD patients,especially for language and memory functions,by modulating the neural activity and functional connectivities in the brain regions related to these functions. |
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