Nonlinear mixed-effects model reveals a distinction between learning and performance in intensive reach training post-stroke.
BACKGROUND
We recently showed that individuals with chronic stroke who completed two sessions of intensive unassisted arm reach training exhibited improvements in movement times up to one month post-training. Here, we study whether changes in movement times during training can predict long-term changes.


METHODS
Sixteen participants with chronic stroke and ten non-disabled age-matched participants performed two sessions of reach training with 600 movements per session. Movement time data during training were fitted to a nonlinear mixed-effects model consisting of a decreasing exponential term to model improvements of performance due to learning and an increasing linear term to model worsening of performance due to activity-dependent fatigability and/or other factors unrelated to learning.


RESULTS
For non-disabled age-matched participants, movement times gradually decreased overall during training and overall changes in movement times during training predicted long-term changes. In contrast, for participants post-stroke, movement times often worsened near the end of training. As a result, overall changes in movement times during training did not predict long-term changes in movement times in the stroke group. However, improvements in movement times due to training, as estimated by the exponential term of the model, predicted long-term changes in movement times.


CONCLUSION
Participants post-stroke showed a distinction between learning and performance in unassisted intensive arm reach training. Despite worsening of performance in later trials, extended training was beneficial for long-term gains.
['Park|Hyeshin|H|', 'Schweighofer|Nicolas|N|']
D002908:Chronic Disease D005260:Female D006801:Humans D007858:Learning D008297:Male D008875:Middle Aged D009068:Movement D017711:Nonlinear Dynamics D020521:Stroke D000071939:Stroke Rehabilitation
Learning Performance Reach training Activity-dependent fatigability Nonlinear statistical mixed-effects model Prediction of long-term gains Stroke rehabilitation