MRI can Predict the Response to Therapeutic Repetitive Transcranial Magnetic Stimulation (rTMS) in Stroke Patients

Abstract

Background: Previous studies suggest that purposeful modulation of excitability by up regulation in primary motor area (M1) in the lesioned hemisphere or down regulation of excitability in M1 intact hemisphere can influence function in the paretic hand..
Objectives: 1- To determine if magnetic resonance imaging (MRI) delineation of lesion has an impact on the modality and site of rTMS
stimulation, and 2- To determine whether MRI can predict the degree of recovery of motor function after rTMS treatment.
Methods: A total of 60 ischemic stroke patients were recruited. Physical examination, mini mental state examination, activities of daily
living assessment, motor subscale of the activity index (AI) and fine hand movement assessment were performed initially and then 2
weeks later (after the end of therapeutic course), then at 4, 8, and 12 weeks. MRI was performed for all patients and used to localize the
site and extent of lesion. The patients were divided to 3 group consisting of 20 patients each: group 1 received repetitive rTMS 5hz at
90% motor threshold for 2.5min on the infarcted hemisphere, group 2 received rTMS 1hz at 110% motor threshold for 2.5min on the intact hemisphere, and group 3 received sham stimulation. All patients received standard physical therapy following each rTMS session.
Results: Patients with total anterior circulation stroke demonstrated on MRI showed no significant improvement when compared to
those with partial anterior circulation, lacunar or posterior circulation strokes. The patients with cortical strokes experienced less
improvement when compared with those with subcortical strokes especially with 1 hz stimulation to intact hemisphere.
Conclusion: MRI can help predict the response to rTMS for stroke rehabilitation and assist the clinician choose the mode and site of
rTMS application.