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Neuronal correlates of objective motor recovery after subcortical stroke: a prospective and longitudinal PET activation study
NeuroImage 13, Number 6,2001, Part 2 of 2 Parts 1 D E@@
SENSORIMOTOR
Neuronal correlates of objective motor recovery after subcortical stroke: a prospective and longitudinal PET activation study Cinzia Calautti*$, Jean-Yves Guincestre*$, Fraqois Leroy*& Rose Marie Marii?*tS, Jean-Claude Baron*+ *MD TPhD $INSERM U320, Caen, France Introduction:
Although following stroke bilateral motor network overactivations during finger motion are well documented, their relation with actual recovery is unknown and no objective measure of motor performance has been documented. The single longitudinal study published so far reported changes in activation pattern with elapsing time (Marshall et al., 2000), but correlation with objective motor scores were not reported. Subjects
and methods:
In a prospective and longitudinal study we studied 5 right-handed patients (592 13 yrs) with right-sided recovering hemiparesis due to first-ever left subcortical stroke. We obtained two 3D-PET H2015 studies (ECAT HR+), the 1st at l-4 months and the 2nd at -8 months after onset (PET1 and PET2, respectively), replicating 4 times 2 conditions: i) metronome-cued right thumb-to-index tapping (TIT) at fixed-rate (1.26 Hz); ii) rest with eyes closed, metronome on. Thus, performance was fixed both in patients over time and in controls. In each patient and control, we obtained an instrumental measure of movement by an accelerometer positioned on the right index finger. Data were assessedindividually with SPM96 and p< 0.05, corrected; controls were 7 healthy age-matched right-handed subjects. We computed the correlations between right hand Motor Scores (max number of TITS in 15 s) and PET Lateral@ Indices (LI = the affected-to-unaffected-hemisphere ratio of activated voxels, Cramer et al., 1997). To estimate the effective TIT frequency during PET scanning the accelerometer sine waves were Fourier transformed according to frequency and the index expressing the degree of deviation from the cued frequency (i.e., 1.26 Hz) was obtained by calculating areas under the curves for both the 0.5-1.5 and the 1.25-1.35 Hz ranges. This Frequency Deviation Index for the patients was compared to that of the controls and from PET1 to PETZ. Results
and comments:
Motor Scores significantly improved from PET1 to PET2 (18?4 and 2925, respectively, pcO.05, paired t-test); 2 pts exhibited mirror movements at PET1 and 1 at PET2. Significant overactivations at PET1 affected the whole motor network bilaterally, but were considerably less extensive at PET2, with a significant LI shift (from .69t .ll to .08? .54, pcO.05). Individual shift magnitude was negatively correlated (Spearman rho= -.975, p
This study documents i) a significant shift of activations towards the unaffected hemisphere despite fixed performance; and ii) a correlation between motor recovery and brain activation patterns at&r stroke, such that the greater the shift, the worse the recovery. In addition, objective movement recording documented that the abnormal PET activation patterns were in fact associated with altered movement execution (despite fixed performance), while the changes in activation patterns over time were associated with normalization of movement execution.
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SENSORIMOTOR
Neuronal correlates of objective motor recovery after subcortical stroke: a prospective and longitudinal PET activation study Cinzia Calautti*$, Jean-Yves Guincestre*$, Fraqois Leroy*& Rose Marie Marii?*tS, Jean-Claude Baron*+ *MD TPhD $INSERM U320, Caen, France Introduction:
Although following stroke bilateral motor network overactivations during finger motion are well documented, their relation with actual recovery is unknown and no objective measure of motor performance has been documented. The single longitudinal study published so far reported changes in activation pattern with elapsing time (Marshall et al., 2000), but correlation with objective motor scores were not reported. Subjects
and methods:
In a prospective and longitudinal study we studied 5 right-handed patients (592 13 yrs) with right-sided recovering hemiparesis due to first-ever left subcortical stroke. We obtained two 3D-PET H2015 studies (ECAT HR+), the 1st at l-4 months and the 2nd at -8 months after onset (PET1 and PET2, respectively), replicating 4 times 2 conditions: i) metronome-cued right thumb-to-index tapping (TIT) at fixed-rate (1.26 Hz); ii) rest with eyes closed, metronome on. Thus, performance was fixed both in patients over time and in controls. In each patient and control, we obtained an instrumental measure of movement by an accelerometer positioned on the right index finger. Data were assessedindividually with SPM96 and p< 0.05, corrected; controls were 7 healthy age-matched right-handed subjects. We computed the correlations between right hand Motor Scores (max number of TITS in 15 s) and PET Lateral@ Indices (LI = the affected-to-unaffected-hemisphere ratio of activated voxels, Cramer et al., 1997). To estimate the effective TIT frequency during PET scanning the accelerometer sine waves were Fourier transformed according to frequency and the index expressing the degree of deviation from the cued frequency (i.e., 1.26 Hz) was obtained by calculating areas under the curves for both the 0.5-1.5 and the 1.25-1.35 Hz ranges. This Frequency Deviation Index for the patients was compared to that of the controls and from PET1 to PETZ. Results
and comments:
Motor Scores significantly improved from PET1 to PET2 (18?4 and 2925, respectively, pcO.05, paired t-test); 2 pts exhibited mirror movements at PET1 and 1 at PET2. Significant overactivations at PET1 affected the whole motor network bilaterally, but were considerably less extensive at PET2, with a significant LI shift (from .69t .ll to .08? .54, pcO.05). Individual shift magnitude was negatively correlated (Spearman rho= -.975, p
This study documents i) a significant shift of activations towards the unaffected hemisphere despite fixed performance; and ii) a correlation between motor recovery and brain activation patterns at&r stroke, such that the greater the shift, the worse the recovery. In addition, objective movement recording documented that the abnormal PET activation patterns were in fact associated with altered movement execution (despite fixed performance), while the changes in activation patterns over time were associated with normalization of movement execution.
S1142