Motor Evoked Potentials of Trunk Muscles in Stroke Patients

ABSTRACT

OBJECTIVE: To evaluate the reorganization of descending motor pathways of trunk muscles in stroke patients. METHOD: Nine patients with unilateral hemispheric stroke were enrolled. Their mean age was 56 years. Transcranial magnetic stimulation (TMS) was applied to unaffected and affected motor cortices in turn and bilateral electromyographic recordings were made from rectus abdominis, external oblique abdominal, and 4 th and 9 th thoracic erector spinae muscles during resting. The onset latency and peak-to-peak amplitude of motor evoked potential (MEP) were measured for each muscle on both sides. RESULTS: Stimulation of the unaffected hemisphere evoked contralateral responses in all patients. Ipsilateral responses were more common in TMS of affected hemisphere. Ipsilateral but not contralateral MEPs were obtained in TMS of affected hemisphere. CONCLUSION: These results demonstrated that the variable availability of bilateral crossed and uncrossed corticomotorneuronal projections among patients could be related with the inconstant occurrence of trunk weakness after unilateral hemispheric stroke.