The Effects Of The Combination Stimulation Paradigm Of Repetitive Transcranial Magnetic Stimulation In Memory Impairment Patients

Objective:We aimed to investigate the effects of rTMS treatment on a new repetitive transcranial magnetic stimulate(rTMS) treatment strategy in elders with memory impairment,which consists of a combination of high-frequency prefrontal and low-frequency temporal rTMS.Methods:Altogether 27 patients with memory impairment involved.They were randomly divided into two groups.We applied the combination stimulation paradigm of rTMS in 13 memory impairment patients as rTMS group,and the control group contains the other 14 subjects.Before treatment,the rTMS group underwent motor evoked potential(MEP) measurement.Then the combined frequency protocol rTMS was applied which begin from high frequency stimulation on the both sides of prefrontal cortex(F_p1/F_p2,200 stimuli,the rate of rTMS depended on their own characteristic alpha frequency,80%-100%MEP threshold value),then followed by low frequency stimulation on both sides of temporal cortex(F7/8,600-800 Stimuli, 1 Hz,80%-120%motor threshold) respectively,with the gradual accretion in the stimuli pulses and intensity.Continuous five days' treatment per month as one course, 5 courses were observed.At the same time,no treatment was administrated on the control group.Before treatment(baseline),all subjects were measured Clinical Memory Scale(CMS),Mini-Mental State Examination(MMSE),Activity of Daily Living Scale(ADL),Global Deteriorate Scale(GDS),Clinical Dementia Rating (CDR),Hachinski Ischemic Scale(HIS) and Hospital Anxiety and Depression Scale (HADS).CMS and HADS were assessed on all participants after 5 courses' observation.Further more,their EEGs were recorded in rest(eye closed) both before and after treatment.Then,the EEG data were analyzed by spectral estimation on Matlab 7.0.Results:1.Memory quotient:①There was no significant difference between the two group before the rTMS treatment(P＞0.05).After treatment,MQ of rTMS group was higher than that in the control group(P＜0.05).②After the treatment,we found MQ was improved in the rTMS group with the comparison of the baseline(P＜0.01),whereas it was declined in the control group(P＜0.01).③The rTMS group showed the higher MQ change rate compared with the control group(P＜0.01).2.The scores of subtests in Clinical Memory Scale.①The scores of 5 subtests in CMS were not significantly different between the two group before the treatment (P＞0.05).After treatment,the scores of three subtests(point-to memory,associative learning,portrait character associated memory items) in the treatment group were higher than those in the control group(P＜0.05).②The scores in subtests of point-to memory and associative learning in the rTMS group showed an noticeable accrescence(P＜0.05,P＜0.01).The control group obtained more decreased scores in the subtests of associative learning,recognition of meaningless,portrait character associated memory items with the comparison of the baseline(P＜0.05,P＜0.01).DCompared with the control group,the change rate of three subtests scores which were point-to memory,associative learning and portrait character associated memory had increased in the rTMS treated group(P＜0.05,P＜0.01).④There was no significant difference among the rate of 5 subtest-score in the control group(P＞0.05). In the rTMS group,the change rate of point-to memory items was highest in all of 5 subtests,which was much higher than recognition of meaningless or portrait character associated memory(P＜0.05).In control group,however,there was no significant difference(P＞0.05).3.Relative power percentage of electroencephalogram.Relative power percentage(RPP) of electroencephalogram(EEG) were not significantly different between the two group before the treatment(P＞0.05).②After the treatment, compared with the control group,the rTMS group showed RPP in low frequency band(δ-θband) decreased in frontal,temporal and occipital regions(P＜0.05);RPP in high frequency band(α-βband) in occipital area(P＜0.05),as well as RPP in y band in temporal area was higher(P＜0.05).③In the control group,RPP in low frequency band(δ-θband) in both temporal and occipital regions increased (P＜0.05),whereas in high frequency band(α-βband) showed a decrease(P＜0.05). In y band,RPP in temporal region also showed a decrease.④In the rTMS treated group,RPP of low frequence band(δ-θband) in temporal and occipital regions declined,in contrast,in high frequency band(α-βband) increased.4.the power ratio of a band toθband(the ratio of a/θ).①the ratio of a/θwasn't significantly different between the two group before the rTMS treatment(P＞0.05). After the treatment,compared with the control group,in the rTMS group the ratio of a/θin frontal,parietal,temporal and occipital regions were significantly lower (P＜0.05),②In the control group,the ratio of a/θin frontal,temporal and occipital regions declined compared with their baseline(P＜0.05);in the rTMS group the ratio of a/θin frontal,temporal and occipital regions increased statistically(P＜0.05).5.Hospital Anxiety and Depression Scale.There was no significant difference between before and after the period of TMS treatment in both group(P＞0.05), Comparison in the two group respectively,there also had no significant difference (P＞0.05).Conc I us ions:1.The memory function in patients with memory impairment will gradually decline if no intervention performed;however,in our study the improvement could be found in memory-scale test after 5 course of rTMS treatment.This suggests that rTMS has a positive effect on memory function in the patients with memory impairment who might develop to dementia.2.rTMS as a safe and effective method could delay the progression of memory impairment through long time(5 courses) treatment.3.The rTMS could decrease the RPP in low frequency(δ-θband) power and increase in high frequency(α-γband) power.This suggested that rTMS treatment could improve brain function.To a certain extent,rTMS could play a resistive part in the natural brain aging.