Langan J, van Donkelaar P
It is likely that when given Constraint-Induced Movement Therapy (CIMT) intervention, years of preferred use of the dominant arm might confer some advantage to individuals with strokes affecting their dominant arm as compared to individuals with the stroke affecting their non-dominant arm.
The purpose of this study was to explore if pre-stroke hand dominance might influence functional outcomes of the paretic hand post-stroke in a CIMT intervention. Additionally, the study also conducted functional imaging to determine if there would be activation changes (on fMRI in the cortex) based on pre-stroke hand-dominance following the CIMT intervention.
Methods:
The study recruited 9 right hand dominant persons 6 months post-stroke. 5 persons had stroke affecting their dominant arm (right), 4 had the stroke affecting their non-dominant arm (left). All individuals were subjected to traditional CIMT for two weeks. A repeated measures design was used for clinical testing and functional imaging.
Results:
1. Functional improvement in hand use following traditional CIMT was statistically significant, regardless of patient's pre-stroke handedness.
2. Statistically significant improvement was observed in more complex tasks such as the pegboard task and part of the Wolf Motor Function Test. There was little to no-significant improvement in simpler tasks like pinch, and tap tasks.
It is suggested that CIMT may help improve multi-joint coordination or enhance compensatory strategies for complex tasks better than for basic movements like tapping and pinching. Although the study notes that this differential improvement across tasks may have been a result of ceiling effect for the tapping/pinch tasks.
3. fMRI showed statistically significant changes in cortical activation for the grip task (increase or decrease in number of active voxels on fMRI) for the more affected hand in tandem with improved functionality in the affected hand; no changes were noted with the less affected-constrained hand. There was no effect of pre-stroke handedness on activation changes either.
Possibilities:
1. Influence of hand dominance on rehabilitation outcome might be more pronounced if there are more severe deficits in hand function post-stroke than that included in this study.
Neurorehabilitation and Neural Repair, Vol.22, No.3, 298-304 (2008)