Refining forelimb asymmetry analysis: Correlation with Montoya staircase contralateral function post-stroke

- A refinement of Forelimb Asymmetry or the Cylinder test analysis is presented, through the separation of palm and fingertip touches.
- This refinement allows better correlation of contralateral function following stroke with that determined with the Montoya Staircase.
- Every animal can easily perform Forelimb Asymmetry, without the necessity of pre-stroke training and diet restriction used in Montoya Staircase.

BackgroundForelimb Asymmetry Test is a simple test of motor function, using exploration behavior of a rat in a novel environment and counting the number of times that a rat touches the wall with either forepaw. Our lab has noticed, however, that there appears to be an increased number of fingertip touches to the wall following a stroke in the impaired forelimb.New methodWe counted the number of times that the animal either laid its palm flat against the wall of the chamber or touched the wall with only its fingertips, for both the left and right forepaws. We also separated bouts of exploration, so we could clearly determine if fingertip touches normally were associated with a transition from resting state to exploration state.Results and comparison with existing methodsFishers exact test indicated that there were significant differences in the way that the animals touched the wall pre-stroke compared to post-stroke, with more fingertip touches occurring post-stroke. Counting palm touches as normal and fingertip touches as abnormal increases the sensitivity of the Forelimb Asymmetry analysis and gives a good correlation with the contralateral functional deficits determined by Montoya Staircase post-stroke. If we counted every wall touch as normal (palm touches and fingertip touches), we see a loss of sensitivity and a poor correlation with contralateral function as determined by Montoya Staircase.ConclusionsThis refinement of the Forelimb Asymmetry analysis improves correlation with Montoya Staircase contralateral function after stroke.