This study aimed to identify the specific facets of post-stroke apathy that influence motor learning during the acquisition phase using a visuomotor transformation task.
This cross-sectional study enrolled 35 stroke survivors (mean age: 77.8±6.4 years, 18 females). Inclusion criteria were: age ≥65 years, a score ≥24 on the Japanese Mini-Mental State Examination, and no current participation in other studies. Exclusion criteria were: inability to comprehend the task or reports of strong fatigue. Apathy was assessed using the Japanese Dimensional Apathy Scale (J-DAS), measuring behavioral, motivational, and emotional facets. Motor learning was evaluated via a visuomotor rotation task using participants' non-paretic upper limb. They moved a cursor to a target on a PC screen with a trackpad. Each trial lasted 30 seconds, and participants completed 12 trials. The pointer's movement was rotated 45 degrees relative to their finger movement. Outcome measures were number of target reaches (NTR) and percentage increase in trajectory length compared to the shortest distance (PTR), analyzed for improvement from the first to twelfth trial. A two-way ANOVA was conducted to verify the apathy's impact on motor learning (between-group: apathy presence vs. absence; within-group: session (first vs. twelfth trial)). Pearson's correlation analysis explored relationships between motor learning improvements and J-DAS scores. All statistical analyses were performed in R 4.1.3, with significance set at p0.05.
19 participants (54.3%) exhibited post-stroke apathy. A significant main effect of group and session was found on NTR improvement rate (F(1, 33) = 4.143, p = 0.049, ηG2 = 0.095, F(1, 33) = 28.850, p 0.0001, ηG2 = 0.127, respectively), but not for PTR. NTR improvement rate negatively correlated with both total J-DAS score (r = -0.492, p = 0.003) and emotional-apathy subscale score (r = -0.493, p = 0.003). PTR improvement rate significantly correlated with the initiation-apathy subscale score (r = -0.395, p = 0.018).
These findings suggest that post-stroke apathy negatively impact motor learning of acquisition phase. This is particularly emotional-apathy, which appears to hinder motor learning in tasks demanding speed and accuracy. Additionally, initiation-apathy may specifically hinder error reduction. Overall, our findings highlight the multifaceted influence of apathy on motor learning of acquisition phase and necessitate longitudinal studies.
This study showed that it is important to consider multidimensional apathy, which requires comprehensive assessment, in stroke survivors who have difficulties with motor learning. The necessity of a multifaceted approach to the assessment and intervention of apathy is suggested to support the smooth acquisition of motor skills in stroke survivors.
Apathy
Motor learning
