We aimed to investigate the role of visuospatial function in motor learning related to hand dexterity in individuals with subacute stroke compared to older adults.
Seventeen individuals with subacute stroke (age: 66.1 ± 13.8, days since onset: 69.3 ± 38.6) and 15 older adults (age: 72.1 ± 3.7) participated in a grasping force control task that involved using a grasping device to grasp targets of three different sizes for 10 seconds each, totaling 30 seconds. Participants performed the tasks without visual information on the monitor and received feedback (FB) after the trial. FB was only provided during practice and not during the test. The stroke group performed the task using their paralyzed upper limb, while the older group used their non-dominant hand. Visuospatial function was assessed using the Rey–Osterrieth Complex Figure Test (ROCFT). The experiment spanned two consecutive days: Day 1 consisted of a pre-test (PRE), practice, and short-term retention test (SRT), and Day 2 consisted of a long-term retention test (LRT) and the ROCFT. Primary outcomes were grasping errors and 3-min recall scores (recall score) from the ROCFT. A linear mixed-effects model was used to analyze changes in grasping errors with group, time, and visuospatial function. The model included time (PRE, SRT, and LRT), group (stroke and older), time–group interaction, and recall score as fixed effects, with participants as a control variable. Data were log-transformed for equal variance between the groups.
The stroke group showed mild upper limb motor impairment (Fugl–Meyer upper extremity: 59.4 ± 5.9). There was not a significant interaction between time and group on motor task (SRT: p = 0.450; LRT: p = 0.704). However, the main effect of time showed significant improvement in both SRT and LRT (SRT, β = -0.96, p .001; LRT, β = -0.73, p .001) compared to PRE. Furthermore, recall score significantly affected motor learning (β = -0.019, p = 0.005).
The stroke group showed similar motor learning in hand dexterity as the older group. The stroke group only exhibited mild upper limb motor impairment, suggests that the motor impairment has a limited effect on motor learning. Visuospatial memory, as reflected in ROCFT recall scores, likely facilitated the retention of visual FB. This may explain why the stroke group showed improvements in hand dexterity comparable to the older group. Furthermore, this study suggested that a 3-min recall test can effectively reflect an individual’s motor learning ability, producing results similar to those of previous research that utilized a 30-min delayed recall test.
The results of this study suggest that rehabilitation programs for hand dexterity should incorporate visuospatial functions.
visuospatial ability
hand dexterity
