http://nnr.sagepub.com/content/27/5/411.abstract?etoc
Abstract
Background. Although functional imaging and neurophysiological approaches reveal alterations in motor and premotor areas after stroke,
insights into neurobiological events underlying these alterations are limited in human studies. Objective.
We tested whether cerebral metabolites related to neuronal and glial
compartments are altered in the hand representation
in bilateral motor and premotor areas and
correlated with distal and proximal arm motor impairment in hemiparetic
persons.
Methods. In 20 participants at >6 months postonset of a subcortical ischemic stroke and 16 age- and sex-matched healthy controls,
the concentrations of N-acetylaspartate
and myo-inositol were quantified by proton magnetic resonance
spectroscopy. Regions of interest identified
by functional magnetic resonance imaging included
primary (M1), dorsal premotor (PMd), and supplementary (SMA) motor
areas.
Relationships between metabolite concentrations and
distal (hand) and proximal (shoulder/elbow) motor impairment using
Fugl-Meyer
Upper Extremity (FMUE) subscores were explored. Results. N-Acetylaspartate was lower in M1 (P = .04) and SMA (P = .004) and myo-inositol was higher in M1 (P = .003) and PMd (P = .03) in the injured (ipsilesional) hemisphere after stroke compared with the left hemisphere in controls. N-Acetylaspartate in ipsilesional M1 was positively correlated with hand FMUE subscores (P = .04). Significant positive correlations were also found between N-acetylaspartate in ipsilesional M1, PMd, and SMA and in contralesional M1 and shoulder/elbow FMUE subscores (P = .02, .01, .02, and .02, respectively). Conclusions.
Our preliminary results demonstrated that proton magnetic resonance
spectroscopy is a sensitive method to quantify relevant
neuronal changes in spared motor cortex after
stroke and consequently increase our knowledge of the factors leading
from these
changes to arm motor impairment.
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