120. Changing in effective cerebral connectivity during the acute phase of stroke: An EEG TMS study

Abstract

The purpose of this study is to investigate possible changes in effective connectivity of the brain secondary to an acute injury such as cerebral ischemia by using TMS-EEG co-registration. 7 stroke patients with single ischemic stroke in the left middle cerebral artery territory within 10 days and upper arm paresis, and 7 age-matched healthy subjects were enrolled in the study. TMS was performed over the left and right primary motor area during multichannel EEG recording. Stroke patients with no muscular twitch in response to TMS stimulation were excluded. After TMS stimulation of the left affected M1 area a in stroke patients we found a different recruitment then in healthy subjects. In stroke patients, cerebral activations between 20 and 70 ms after the stimulation were steadily bilateral and we found a significantly higher strength in the whole affected hemisphere. This study demonstrated a clear modification in effective cortical connectivity during the acute phases of stroke. The EEG-TMS technique has proven useful in evaluating the modification of synaptic plasticity that occur in the acute phase of stroke, offering the opportunity to acquire information for prediction of the prognosis or new therapeutic approaches.