It is vastly more important to DELIVER HAND FUNCTION than predict it! When the hell will stroke leadership get a strategy going to DELIVER 100% RECOVERY? I'm guessing never since survivors are not in charge.
Yeah, Bruce Dobkin is a superstar stroke researcher but I think even he is not actually solving stroke to get survivors recovered. Hope he has 100% stroke recovery solved before he becomes the 1 in 4 per WHO that has a stroke!
Motor Cortex Activation During Treatment May Predict Therapeutic Gains in Paretic Hand Function After Stroke
Abstract
Background and Purpose—
Functional brain imaging after stroke offers insight into motor network
adaptations. This exploratory study examined whether motor cortical
activation captured during arm-focused therapy can predict paretic hand
functional gains.
Methods—
Eight hemiparetic patients had serial functional MRI (fMRI) while
performing a pinch task before, midway, and after 2 weeks of
constraint-induced therapy. The Wolf Motor Function Test (WMFT) was
performed before and after intervention.
Results—
There was a linear reduction in ipsilateral (contralesional) primary
motor (M1) activation (voxel counts) across time. The midpoint M1
Laterality Index anticipated post-therapeutic change in time to perform
the WMFT. The change in ipsilateral M1 voxel count (pre- to mid-)
correlated with the change in mean WMFT time (pre- to post-).
Conclusions—
The relationship between brain activation during treatment and
functional gains suggests a use for serial fMRI in predicting the
success and optimal duration for a focused therapeutic intervention.
Functional
MRI (fMRI) has revealed reorganization in the primary and secondary
motor cortices during poststroke recovery and after therapeutic
interventions.1
Few studies have explored the evolution of brain activation in relation
to behavioral gains in a “one-to-one” correspondence during a specific
rehabilitation intervention.2
This exploratory study examined whether the brain activation midway
through a 2-week arm-focused intervention might capture adaptations
induced by the initial week of training and, in turn, could be used to
anticipate post-therapeutic behavioral changes in paretic hand function.
If so, this brain–behavior correspondence may offer guidance to
determine an optimal duration for task-specific therapy.2
Subjects and Methods
Eight
patients with hemiparetic stroke (Fugl-Meyer [FM] motor score 33 to 62)
participated. Inclusion criteria were >3 months after stroke,
ability to perform the fMRI task, and a minimum of 10° of voluntary
wrist and finger extension. Lesions varied in location, but all spared
the hand motor representation (M1). No alternative therapy group was
studied. Seven healthy volunteers were scanned twice to test the
reproducibility of fMRI activation.
Physical Therapy and Functional Measure
All patients received constraint-induced therapy for 2 weeks as defined for the EXCITE trial.3 The Wolf Motor Function Test (WMFT)4
was performed before and after intervention. The behavioral outcome
measure consisted of 6 dexterity items from the full 15-item WMFT (Lift
Can; Lift Pencil; Lift Paper Clip; Stack Checkers; Flip Cards; Turn Key
in Lock) that most directly captured fine motor control. The change in
mean WMFT (mWMFT) time for the 6-item subset was correlated with that
for the 15-item test (r=0.98), indicating reliability and
validity for the subset. The pre-mWFT–post-mWFMT (absolute time)
difference was used as a proxy for functional change in motor skill.
fMRI Acquisition
fMRI acquisition parameters were described previously.5
fMRI sessions were performed before intervention, midintervention, and
after intervention, each with 4 30-s bouts of repetitive pinch
alternating with 5 30-s rest periods. The pinch apparatus included a
vertical plastic tube connected to a pressure transducer. The task
required tube compression with the index and middle fingers against the
thumb, creating enough pressure to match 50% of maximum, viewed through
goggles as a target line, and paced by auditory cues at 75% maximum
rate. These parameters were maintained constant across the 3 sessions.
Practice before each fMRI session minimized unwanted movements and
deviations from consistent task performance.
Data Analysis
fMRI data were analyzed as described previously.5,6 Volumes related to head motion (>2 mm), and associated movements (visually identified from videotape) were excluded. Z statistic images were thresholded at Z>3.1, and significant clusters were defined atP<0.01
(corrected for multiple comparisons). Regions of interest (ROIs) were
set in bilateral M1 and dorsal premotor (PMd) areas. Percentage signal
change (% SC) and voxel counts (VCs) within each ROI were measured and a
Laterality Index
[LI=(contralateral−ipsilateral)/(contralateral+ipsilateral)]
(contralateral and ipsilateral activation to the hand movement. LI
ranges from −1 [all ipsilateral activation] to 1 [all contralateral
activation]) was calculated using VC for each ROI. Linear Mixed Model
was used for intersession comparisons of fMRI variables (% SC, VC),
pinch pressure, and rate, separately. Individual linear regression
analyses were performed between LI, VC (M1 and PMd; independent
variable) pre-, mid-, and post- and the post-pre–mWMFT time difference
(dependent variable). Pearson correlation coefficient analysis was used
to assess the relationship between changes in fMRI measures and changes
in mWMFT time. Preintervention fMRI from patients 5 and 6 was
technically unusable.
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