Effects of visual terminal feedback on hand dexterity in relation to visuospatial ability in subacute stroke: a preliminary study

Abstract

Hand dexterity impairments in patients with stroke reduce activities of daily living (ADL) and quality of life. Visuospatial ability is associated with motor learning, but this has not previously been reported in patients with subacute stroke. We aimed to investigate whether visual terminal feedback (FB) affected motor learning of hand dexterity and the relationship among visuospatial ability. Overall, 17 subacute stroke patients (age: 66.1 ± 13.8 years) with mild upper limb motor impairment were included. The experimental task was the grasping force control task. The visuospatial task was the Rey-Osterrieth Complex Figure Test (ROCFT). The experimental protocol was conducted in 2 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. Grasping errors were significantly decreased in the SRT and LRT than in the PRE. Furthermore, ROCFT scores (copy and recall) and LRT grasping errors were moderately negatively correlated (ρ = -0.51 and - 0.53). In conclusion, visuospatial ability is an important factor associated with motor learning in subacute stroke patients. Future studies should use visual terminal FB, and training programs for visuospatial ability should be considered in stroke rehabilitation.

Keywords: Augmented feedback; Grasping force adjustment ability; Motor learning; Stroke; Task-specific training; Visuospatial ability.

Fig. 1

Progress of the participants through the experiment. Two participants have dropped out of the study, and 17 participants are included in the final analysis.

Fig. 2

Change in ability to adjust grasping force. (a) Results of grasping errors. The center line shows the median value. Whiskers indicate values below 1.5 times the interquartile range (IQR) above the first quartile and up to 1.5 times the IQR above the third quartile; data beyond this are shown as outliers, indicated by black points. Abbreviations: PRE, pre-test; SRT, short-term retention test; LRT, long-term retention test. (b) Results of grasping errors in each practice block. Abbreviations: B1–B5, Block 1–5.

Fig. 3

Correlation of test performance with motor function and visuospatial function. Values in tiles indicate Spearman rank correlation coefficients. Combinations showing significant correlations are color coded, with Spearman’s rank correlation coefficients close to 1 shown in red and those close to −1 shown in blue. Combinations that do not show significant correlations are shown in white. Abbreviations: PRE, pre-test; SRT, short-term retention test; LRT, long-term retention test; FMUE, Fugl–Meyer assessment for upper extremity; ARAT, Action research arm test; Copy, copy score; ORG, organization score; Recall, 3-min delayed-recall score.

Fig. 4

Experimental equipment and experimental environments. (a) Grasping device (right) and control box (left). We can quantitatively assess the participant’s grasping force in the range of 0–0.5 kg. (b) Feedback during the experimental task. Participants receive feedback on how accurately they adjusted the measured grasping force (red line) relative to the target grasping force (blue line).

Fig. 5

Experimental task. The target grasping force is shown in blue solid line.

Fig. 6

Experimental schedule. The participants perform the pre-test (PRE), practice test, and short-term retention test (SRT) on day 1 and the long-term retention test (LRT) and Rey–Osterrieth Complex Figure Test (ROCFT) on day 2. One block consists of three trials, with one block for each of the three tests (PRE, SRT, and LRT) and five blocks (B1 to B5) for the practice test. SRT is conducted 5 min after completion of the last trial of the practice test, and LRT is conducted 24 h after the SRT.