Efficacy of Upper Extremity Robotic Therapy in Subacute Poststroke Hemiplegia
An Exploratory Randomized Trial
Background and Purpose—Our aim was to study the efficacy of robotic therapy as an adjuvant to standard therapy during poststroke rehabilitation.
Methods—Prospective, open, blinded end point, randomized, multicenter exploratory clinical trial in Japan of 60 individuals with mild to moderate hemiplegia 4 to 8 weeks post stroke randomized to receive standard therapy plus 40 minutes of either robotic or self-guided therapy for 6 weeks (7 days/week). Upper extremity impairment before and after intervention was measured using the Fugl–Meyer assessment, Wolf Motor Function Test, and Motor Activity Log.
Results—Robotic therapy significantly improved Fugl–Meyer assessment flexor synergy (2.1±2.7 versus −0.1±2.4; P<0.01) and proximal upper extremity (4.8±5.0 versus 1.9±5.5; P<0.05) compared with self-guided therapy. No significant changes in Wolf Motor Function Test or Motor Activity Log were observed. Robotic therapy also significantly improved Fugl–Meyer assessment proximal upper extremity among low-functioning patients (baseline Fugl–Meyer assessment score <30) and among patients with Wolf Motor Function Test ≥120 at baseline compared with self-guided therapy (P<0.05 for both).
Conclusions—Robotic therapy as an adjuvant to standard rehabilitation may improve upper extremity recovery in moderately impaired poststroke patients. Results of this exploratory study should be interpreted with caution.
Clinical Trial Registration—URL: http://www.umin.ac.jp/. Unique identifier: UMIN000001619.
Although stroke affects nearly 15 million people worldwide annually, with 5 million experiencing some degree of permanent paralysis,1 appropriate rehabilitation programs can improve motor function and quality of life.2 For example, repetitive voluntary movement of the paralyzed limb can improve function and remodel neural circuits.3 Robotic technologies may be effective for stroke rehabilitation because they can produce consistent repetitive patterns in an automated manner.4 However, although one recent systematic review reported that robot-assisted training improves activities of daily living and arm function,5 another reported that robotic therapy is not more effective than standard therapy, except as an adjuvant.6 The present study aimed to investigate whether robotic therapy is a more effective adjuvant to standard rehabilitation than self-guided therapy in subacute poststroke rehabilitation.
Materials and Methods
This prospective, multicenter, randomized, open, blinded end point, exploratory clinical trial examined robotic therapy combined with standard upper extremity (UE) therapy in patients with subacute poststroke hemiplegia. All study protocols were approved by the institutional review boards of each facility. Full study details are provided in the online-only Data Supplement.
Patients were recruited from inpatient stroke centers at 6 participating facilities. Eligible patients were 20 to 80-years-old, experienced their first stroke in the previous 4 to 8 weeks, and exhibited UE Brunnstrom stage III to IV movement. Full inclusion/exclusion criteria are included in the online-only Data Supplement. All participants provided written informed consent.
We a priori selected 30 patients per group, which in a post hoc power calculation gave 64.2% power to detect a 3-point difference in Fugl–Meyer assessment (FMA) scores, with 25-point variance between groups (P<0.05). Participants were randomized by central registration staff using Zelen’s method combined with the minimization method to control for confounders (age, sex, Oxfordshire Community Stroke Project classification, Brunnstrom stage, and facility).
All patients received 40 minutes of standard therapy and 40 minutes of either self-guided or robotic therapy daily for 6 weeks. Standard therapy, which was administered by an experienced therapist, depended on each patient’s condition and comprised UE exercises for stretching, range of motion, reaching, grasping/releasing, and pinching, as well as activities of daily living training. The robotic therapy system (ReoGo; Motorika Medical, Caesaria, Israel) included 5 preprogrammed movement patterns and 5 levels of robotic assistance targeted toward proximal upper limb function, which were selected by the therapist for each patient. Similarly, a therapist selected appropriate items and assistance levels from a list of self-guided exercises for self-guided therapy. In both groups, the patient performed the exercises alone with the therapist supervising from a distance for risk management and to ensure fidelity to the selected program. Participants in both groups were allowed to stop the session at any time if pain or fatigue was considered excessive.
Outcome measures were the FMA (UE section of the FMA [0–66 points] as well as the proximal UE [0–36 points] and flexor synergy [0–12 points] subscores), the Wolf Motor Function Test (WMFT; mean time [0–120 s] needed to perform each of 15 tasks and proximal UE tasks [7 tasks]), and the Motor Activity Log (amount of use and quality of movement for 14 activities of daily living on 6-point Likert scales [0–5 points]). We did not a priori select one primary effectiveness outcome. Each outcome was evaluated at baseline (before any rehabilitation) and after 6-week intervention by therapists blinded to the randomization.
Adverse events were defined as described in the online-only Data Supplement. Safety of the ReoGo system was also evaluated according to the occurrence of accidents during each session (eg, unexpected shutdown, overstretching of the arm), pain (measured by a 100-mm visual analogue scale), and muscle spasticity (measured using the modified Ashworth scale).
Data were analyzed using SAS version 9.1.3 or JMP version 12.0.1 (SAS Institute, Cary, NC) and presented as the mean±standard deviation (SD). Baseline group differences were tested by Fisher exact test (categorical) or 2-sample t test (ordinal). Treatment effectiveness was evaluated by changes in FMA, WMFT, and Motor Activity Log (baseline versus postintervention) using 1- and 2-sample t tests (within- and between-group comparisons, respectively). Analysis of covariance was used to control for baseline FMA score.
For subgroup analyses, participants were divided into higher and lower UE function (FMA <30 and ≥30, respectively, where FMA=30 represented the baseline mean). Similarly, the WMFT score was categorized as ≥120 s or <120 s. McNemar and 2-sample Wilcoxon tests (within- and between-group comparisons, respectively) were conducted. P<0.05 was considered significant for all statistical comparisons. All statistical analyses were conducted by the first author who was blinded to treatment allocation.
Of 715 patients screened between November 2008 and April 2010, 60 were randomized to either robotic or self-guided therapy in addition to standard rehabilitation (Figure). Four patients randomized to self-guided therapy did not complete the study. Baseline patient characteristics were not significantly different between groups (Table I in the online-only Data Supplement).
Changes in FMA, WMFT, and Motor Activity Log scores from baseline to the end of the intervention period between the 2 groups are reported in Table. Change in total FMA UE score was not significantly different between groups (P=0.255). However, changes in FMA proximal UE and FMA flexor synergy were significantly different (P=0.048 and P=0.003, respectively). Although baseline FMA flexor synergy was significantly different between groups at baseline (6.7±3.9 versus 8.7±2.8, robotic versus self-guided, respectively; P=0.035), the change remained significant when baseline score was included as a covariate (difference, 1.4; 95% confidence interval, 0.15–2.60; P=0.028). No significant differences in total or proximal UE WMFT scores (P=0.764 and P=0.330, respectively) or in amount of use or quality of movement (P=0.982 and P=0.943, respectively) were observed. Results on other outcome measures (ie, Simple Test for Evaluating Hand Function [STEF], Range of Motion, Modified Ashword Scale) are reported in Table II in the online-only Data Supplement.
The lower UE function class (FMA <30) exhibited a greater gain in FMA score under robotic therapy compared with self-guided therapy (6.6±5.1 versus 2.2±6.2; P=0.041). No significant difference in gain was observed in the higher UE function class (2.4±3.8 versus 1.7±4.9; P=0.69; robotic versus self-guided, respectively). Likewise, among patients with WMFT ≥120 s, the robotic therapy group had significantly more improvement in proximal UE than the self-guided therapy group (Table III in the online-only Data Supplement).
Although common poststroke adverse events were observed at comparable frequencies in each group, no serious adverse events related to the intervention were observed (Table IV in the online-only Data Supplement).
A 9- to 10-point change in FMA UE has been reported as the minimal clinically important difference for UE motor recovery among patients with subacute stroke.7 In the present study, the greater gain in FMA because of robotic therapy compared with self-guided therapy (9.5 versus 6.9, respectively) amounted to a clinically significant improvement, which is consistent with other studies.5
Our subgroup analyses suggest that repetitive movement exercises, such as during robotic therapy, may benefit relatively severe acute/subacute poststroke patients who are beginning to naturally recover.8 Although some studies suggest that robotic therapy is not more effective than intensive therapist–guided therapy for improving UE function,6,9 our study used individualized rather than fixed robotic therapy programs, suggesting that individualized programs may promote successful intervention.
This study has several limitations: a focus on moderately impaired patients only; duration and intervention period not based on a pilot study; and no longitudinal follow-up. Future studies should investigate more severely impaired patients with long-term follow-up.
Our findings suggest that robotic therapy may be a useful alternative to self-training as an adjuvant to therapist-guided standard rehabilitation, especially for some standard treatments, such as repetitive movement exercises, and in patients with more severe UE impairment. Results of this exploratory study should be interpreted with caution.
Sources of Funding
This work was supported by Teijin Pharma Ltd (Tokyo, Japan).
The online-only Data Supplement is available with this article at http://stroke.ahajournals.org/lookup/suppl/doi:10.1161/STROKEAHA.115.012520/-/DC1.
- Received December 30, 2015.
- Revision received February 12, 2016.
- Accepted February 18, 2016.
- © 2016 American Heart Association, Inc.
- 1.↵World Health Organization. Stroke, cerebrovascular accident. Available from: http://www.emro.who.int/health-topics/stroke-cerebrovascular-accident/index.html. Accessed on November 13, 2015.
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