Robot Fully Assisted Upper-Limb Functional Movements Against Gravity to Drive Recovery in Chronic Stroke: A Pilot Study

Abstract

Background: Stroke is becoming more and more a disease of chronically disabled patients, and new approaches are needed for better outcomes. An intervention based on robot fully assisted upper-limb functional movements is presented.

Objectives: To test the immediate and sustained effects of the intervention in reducing impairment in chronic stroke and to preliminarily verify the effects on activity.

Methodology: Nineteen patients with mild-to-severe impairment underwent 12 40-min rehabilitation sessions, 3 per week, of robot-assisted reaching and hand-to-mouth movements. The primary outcome measure was the Fugl-Meyer Assessment (FMA) at T1, immediately after treatment (n = 19), and at T2, at a 6-month follow-up (n = 10). A subgroup of 11 patients was also administered the Wolf Motor Function Test Time (WMFT TIME) and Functional Ability Scale (WMFT FAS) and Motor Activity Log (MAL) Amount Of Use (AOU), and Quality Of Movement (QOM).

Results: All patients were compliant with the treatment. There was improvement on the FMA with a mean difference with respect to the baseline of 6.2 points at T1, after intervention (n = 19, 95% CI = 4.6-7.8, p < 0.0002), and 5.9 points at T2 (n = 10, 95% CI = 3.6-8.2, p < 0.005). Significant improvements were found at T1 on the WMFT FAS (n = 11, +0.3/5 points, 95% CI = 0.2-0.4, p < 0.004), on the MAL AOU (n = 11, +0.18/5, 95% CI = 0.07-0.29, p < 0.02), and the MAL QOM (n = 11, +0.14/5, 95% CI = 0.08-0.20, p < 0.02).

Conclusions: Motor benefits were observed immediately after intervention and at a 6-month follow-up. Reduced impairment would appear to translate to increased activity. Although preliminary, the results are encouraging and lay the foundation for future studies to confirm the findings and define the optimal dose-response curve.

Clinical trial registration: www.ClinicalTrials.gov, identifier: NCT03208634.

Keywords: passive motion; reaching; recovery of function; rehabilitation; robotics; stroke; task oriented training; upper extremity.

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2022 Caimmi, Giovanzana, Gasperini, Molteni and Molinari Tosatti.

Figures

Figure 1

Study flow chart. The pilot trial took place from October 2013 to October 2014. Twenty-four patients selected from the Villa Beretta database were called over the phone and invited to participate in the study. Seventeen agreed and were screened; 5 were excluded, mainly because they were not able to hold the robot handle during one of the two movements, and 7 refused to participate. From March 2015 to March 2016, a total of 40 patients with chronic stroke who were referred to the outpatient clinic of Villa Beretta were screened; 23 were excluded because of not meeting the inclusion criteria (insufficient shoulder and elbow active ROM or inability to hold the robot handle), and 6 refused to participate. The most common reason for refusing to participate referred to difficulties in reaching the facility.

Figure 2

Assisted RM: starting with the robot handle just above the thigh, the assisted Reaching Movement (RM) consisted of compound movements of shoulder flexion and elbow extension, getting as far as 90 degrees of shoulder flexion and fully extended elbow were reached.

Figure 3

Assisted Hand-to-Mouth Movement (HtMM): Starting with the robot handle just above the thigh, the assisted HtMM consisted in flexing the elbow (and the shoulder) to position the robot-handle in front of the mouth. Importantly, the handle was free to rotate and, therefore, the patient had to put it actively (performing wrist internal/external rotation movements) in the right position, which was with its extremity pointing toward the mouth.

Figure 4

Differences in Fugl-Meyer Assessment (FMA) at T1 vs. T0 plotted against patients' age (upper panel), months from stroke (middle panel), and FMA scores at baseline. Differences are expressed as absolute values ΔFMA = FMAT1 -FMAT0 (left panel) and potential recovery ΔFMANOR = ΔFMA/(66-FMAT0) (right panel). For each plot, the linear regression curve along with the r-squared value is also shown.

Figure 5

Draw-A-Person test of two chronic patients. Left panel, the two patients performing the robot assisted movements (first trials very left pictures) and after some sessions of training. In the beginning, they were not able to place the robot handle in front of the mouth as requested. Right panel, the pre and posttreatment Draw-A-Person test.