Effect of low frequency repetitive transcranial magnetic stimulation on the recovery of neural function in patients with cerebral infarction

Abstract

Objective To study the effect of low frequency repetitive transcranial magnetic stimulation (rTMS) on the recovery of neural function in patients with cerebral infarction.Methods Thirty cerebral infarction patients with hemiparalysis were divided randomly into three groups: unaffected side stimulation group ( 1Hz rTMS on M1 area of unaffected hemisphere, n = 10), affected side stimulation group ( 1Hz rTMS on M1 area of affected hemisphere, n = 10), and control group without rTMS, n = 10).All the groups were assessed with their motor function and ADL scores ( NIHSS, MBI) and corticospinal excitability (MEP, CMCT ) before and after 10 and 40 days of treatment.Three patients were chosen randomly in each group who accepted magnetic resonance spectroscopy (MRS) examination before and after 40 days of treatment and assessed with regard to the ratio of N-acetyl aspartate/creating(NAA/Cr).Results Before treatment the scores of National Institute of Health Stroke Scale (NIHSS), modified Barthel Index( MBI), Motor evoked potential (MEP) and central motor conduction time (CMCT) were not statistically different among the three groups ( P > 0.05 ).After treatment, scores of NIHSS and MBI were obviously higher than those before treatment (P < 0.01 ) in rTMS groups no matter the rTMS was applied on the affected or unaffected hemisphere.However, the score in unaffected side stimulation group was higher than that in the affected side stimulation group ( P < 0.05 ).The MEP latency and CMCT was significantly shorter after treatment in all the stimulation groups, with the unaffected side stimulation group improved to a significantly greater extent, in terms of MEP latency and CMCT than the affected side stimulation and control groups at the 10th d and 40th d of treatment(P <0.05 or P <0.01 ).There was a significantly higher ratio of NAA/Cr in two rTMS treatment groups compared with control group.Conclusion Low frequency rTMS on M1 of the unaffected or affected hemisphere can both improve neural function in patients with acute cerebral infarction, rTMS on unaffected hemisphere seems more effective than that on affected hemisphere. Key words: Repetitive transeranial magnetic stimulation; Cerebral infarction; Neural function; Motor evoked potential; Magnetic resonance spectroscopy