P 217. Analysis of cortical reorganization after stroke

Abstract

Introduction Transcranial magnetic stimulation (TMS) is a valuable non-invasive method for investigation functional changes of the motor cortex after stroke ( Groppa et al., 2012 , Hendricks et al., 2003 , Nascimbeni et al., 2006 ). Objectives The purpose of this study was to assess the excitability of the motor cortex of affected hemisphere (AH) and unaffected hemisphere (UH) in patients with stroke. Materials and methods The study involved 48 patients with cerebral hemispheric ischemic stroke in subacute period (mean age-66, 15 ± 1,53 years). Single-pulse TMS was performed to evaluate motor evoked potential (MEP) and resting motor threshold (rMT) with figure-of-eight coil Cool-B65 connected to magnetic stimulator MagPro R100 (Medtronic A/S, Denmark). Results The MEP from AH was not obtained even with facilitation in 27.08% patients. The MEP from AH was registered with facilitation in 16.67% patients. The significantly smaller MEP amplitude and the significantly higher rMT elicited from AH than that of MEP amplitude and rMT elicited from UH were observed in 31.25% patients. Only the significantly higher rMT elicited from AH than that rMT elicited from UH was occurred in 25% patients. Based on TMS results it is useful to distinguish four degrees of reducing excitability of the motor cortex of AH of post-stroke patients: rough, severe, moderate and mild. Conclusion MEP and rMT are informative criteria for defining the functional state of the motor cortex and features of cortical reorganization after stroke. The graduation of reducing excitability of the motor cortex of AH is proposed for use in clinical practice and could be considered in evaluation the prognosis after stroke.