Effectiveness of Robot-Assisted Upper Limb Training on Spasticity, Function and Muscle Activity in Chronic Stroke Patients Treated With Botulinum Toxin: A Randomized Single-Blinded Controlled Trial

Abstract

Background: The combined use of Robot-assisted UL training and Botulinum toxin (BoNT) appear to be a promising therapeutic synergism to improve UL function in chronic stroke patients. Objective: To evaluate the effects of Robot-assisted UL training on UL spasticity, function, muscle strength and the electromyographic UL muscles activity in chronic stroke patients treated with Botulinum toxin. Methods: This single-blind, randomized, controlled trial involved 32 chronic stroke outpatients with UL spastic hemiparesis. The experimental group (n = 16) received robot-assisted UL training and BoNT treatment. The control group (n = 16) received conventional treatment combined with BoNT treatment. Training protocols lasted for 5 weeks (45 min/session, two sessions/week). Before and after rehabilitation, a blinded rater evaluated patients. The primary outcome was the Modified Ashworth Scale (MAS). Secondary outcomes were the Fugl-Meyer Assessment Scale (FMA) and the Medical Research Council Scale (MRC). The electromyographic activity of 5 UL muscles during the "hand-to-mouth" task was explored only in the experimental group and 14 healthy age-matched controls using a surface Electromyography (EMGs). Results: No significant between-group differences on the MAS and FMA were measured. The experimental group reported significantly greater improvements on UL muscle strength (p = 0.004; Cohen's d = 0.49), shoulder abduction (p = 0.039; Cohen's d = 0.42), external rotation (p = 0.019; Cohen's d = 0.72), and elbow flexion (p = 0.043; Cohen's d = 1.15) than the control group. Preliminary observation of muscular activity showed a different enhancement of the biceps brachii activation after the robot-assisted training. Conclusions: Robot-assisted training is as effective as conventional training on muscle tone reduction when combined with Botulinum toxin in chronic stroke patients with UL spasticity. However, only the robot-assisted UL training contributed to improving muscle strength. The single-group analysis and the qualitative inspection of sEMG data performed in the experimental group showed improvement in the agonist muscles activity during the hand-to-mouth task. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03590314.

Keywords: electromyography; rehabilitation; robotics; spasticity; upper limb.

Figures

Figure 1

The upper limb robot-assisted training setting.

Figure 2

Flow diagram of the study.

Figure 3

EMGs muscle activity during the “hand-to-mouth” task in healthy controls.

Figure 4

EMGs muscle activity during the “hand-to-mouth” task in stroke patients before and after the upper limb Robot-assisted training.

Figure 5

Lesions displayed on the magnetic resonance imaging brain template and electromyographic activity of the five upper limb muscles during the “hand-to-mouth” task was explored using a surface Electromyography (EMGs) in two patients. (A) Top left: Lesion Mapping (patient 1). Magnetic resonance imaging showed a lesion involving the left fronto-parietal lobes. Brodmann areas 48, 40, 39, 6, 44, 45, 3, 7, 22, 41, 2, 42, 4, 19, 43, 37, 21,47,9, 46, 1, 18, 23, 10 (MRIcron software, http://www.mricro.com/mricron). The electromyographic activity of the 5 UL muscles during the “hand-to-mouth” task was explored using a surface Electromyography (EMGs). (B) Top right: Lesion Mapping (patient 2). Magnetic resonance imaging showed a lesion involving the left frontal lobe. Brodmann areas 48, 45, 44, 6, 46, 43, 4, 3, 47, 32, 9, 38, 22, 10 (MRIcron software, http://www.mricro.com/mricron). The electromyographic activity of the 5 UL muscles during the “hand-to-mouth” task was explored using a surface Electromyography (EMGs).