Premium
Reperfusion normalizes motor activation patterns in large‐vessel disease
Author(s) -
Chmayssani Mohamad,
Lazar Ronald M.,
Hirsch Joy,
Marshall Randolph S.
Publication year - 2009
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.21554
Subject(s) - cardiology , supplementary motor area , cerebral blood flow , hemodynamics , functional magnetic resonance imaging , medicine , statistical parametric mapping , magnetic resonance imaging , perfusion , finger tapping , psychology , neuroscience , audiology , radiology
Objective Hemodynamic impairment in one hemisphere has been shown to trigger ipsilateral motor activation in the opposite hemisphere on functional imaging. We hypothesized that reversing the hypoperfusion would normalize the motor activation pattern. Methods We studied four patients with high‐grade stenosis and impaired vasomotor reactivity (VMR) but no stroke. Functional magnetic resonance imaging motor activation pattern before and after VMR normalization was compared with seven healthy control subjects scanned at an interval of 3 months using voxel‐wise statistical parametric maps and region of interest analysis. Subjects performed a repetitive hand closure task in synchrony with 1Hz metronome tone. We used repeated‐measures analysis of variance to compute the interaction between group (patients/control subjects) and time by obtaining the average blood oxygen level dependent signal of three motor regions of interest in each hemisphere. Results Two patients normalized their VMR after spontaneous resolution of dissection, and two after revascularization procedures. Both voxel‐wise statistical maps and region of interest analysis showed that VMR normalization was associated in each case with a reduction in the atypical activation in the hemisphere opposite to the previously hypoperfused hemisphere ( p < 0.001). Interpretation In the presence of a physiological stressor such as hypoperfusion, the brain is capable of dynamic functional reorganization to the opposite hemisphere that is reversible when normal blood flow is restored. These findings are important to our understanding of the clinical consequences of hemodynamic failure and the role of the ipsilateral hemisphere in maintaining normal neurological function. Ann Neurol 2009;65:203–208