Article

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.

Langue : ANGLAIS