Brain parenchymal fraction predicts motor improvement following intensive task-oriented motor rehabilitation for chronic stroke.
OBJECTIVE
Infarct volume and location have a weak relationship with motor deficit in patients with chronic stroke. Recent research has focused on the relationship between spared or seemingly "healthy" neural tissue and motor function. In this study we examined MRI scans of patients with chronic stroke to determine if characteristics of seemingly normal parenchyma could predict either response to different forms of upper extremity physical rehabilitation or to pre-treatment motor status.


METHODS
Individuals with chronic stroke (ages 60.6 ± 11.9 years) and mild/moderate upper extremity hemiparesis were administered either CI therapy (n = 14) or a comparison therapy (n = 29). The patients were assessed prior to and following therapy with MRI scans and the Wolf Motor Function Test (WMFT) Performance Time measure. Total voxels in combined grey matter (GM) and white matter (WM) segments (parenchymal volume) were divided by total voxels in GM, WM, and cerebrospinal fluid segments (intracranial volume) to obtain the brain parenchymal fraction (BPF).


RESULTS
BPF correlated with treatment gains on the WMFT (r(43) = -0.31, p = 0.04). Significant correlations between pre-treatment motor function and BPF were not observed.


CONCLUSIONS
Individuals with greater BPFs after stroke show larger arm function gains after CI therapy, suggesting that reductions in volume of normal-appearing tissue may relate to ability to benefit from rehabilitation therapy in chronic stroke.
Department of Psychology, University of Alabama at Birmingham, AL 35233, USA. tar81285@uab.edu
Tyler
T
Rickards
Edward
E
Taub
Chelsey
C
Sterling
Michael J
MJ
Graham
Ameen
A
Barghi
Gitendra
G
Uswatte
Victor W
VW
Mark
D000368:Aged; D020520:Brain Infarction / Q000209:etiology* / Q000473:pathology; D002908:Chronic Disease; D005081:Exercise Therapy / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015201:Meta-Analysis as Topic; D008875:Middle Aged; D009069:Movement Disorders / Q000150:complications / Q000175:diagnosis / Q000209:etiology; D011237:Predictive Value of Tests; D020127:Recovery of Function / Q000502:physiology*; D012149:Restraint, Physical / Q000379:methods*; D018709:Statistics, Nonparametric; D020521:Stroke / Q000150:complications*; D000071939:Stroke Rehabilitation