Clinical Interpretation of Working Volume and Weight Support in Upper Limb Robotic Neurorehabilitation after Stroke

Marco Iosa,Alessandro Cruciani,Giovanni Morone,Alex Martino Cinnera,Fioravante Capone,Matteo Paolucci,Vincenzo Di Lazzaro,Stefano Paolucci

doi:10.3390/app112412123

Abstract

In the past two decades, many studies reported the efficacy of upper limb robotic rehabilitation in patients after stroke, also in its chronic phase. Among the possible advantages of robotic therapy over conventional therapy are the objective measurements of kinematic and kinetic parameters during therapy, such as the spatial volume covered by the patient’s upper limb and the weight support provided by the robot. However, the clinical meaning and the usability of this information is still questioned. Forty patients with chronic stroke were enrolled in this study and assessed at the beginning of upper limb robotic therapy (Armeo® Power) and after two weeks (ten sessions) of therapy by recording the working volume and weight support provided by the robot and by administering six clinical scales to assess upper limb mobility, strength, spasticity, pain, neurological deficits, and independency. At baseline, the working volume significantly correlated with spasticity, whereas weight support significantly correlated with upper limb strength, pain, spasticity, and neurological deficits. After two weeks of robotic rehabilitation, all the clinical scores as well as the two parameters improved. However, the percentage changes in the working volume and weight support did not significantly correlate with any of the changes in clinical scores. These results suggest caution in using the robotic parameters as outcome measures because they could follow the general improvement of the patient, but complex relationships with clinical features are possible. Robotic parameters should be analyzed in combination with the clinical scores or other objective measures because they may be informative about therapy progression, and there is a need to combine their clinical, neuroscientific, and biomechanical results to avoid misleading interpretations.

Highlights

In the past two decades, the numbers and types of commercial robots used in rehabilitation have increased [1]
Data referred to baseline pre-robotic rehabilitation (T1) and after 2 weeks (T2) during which upper limb robotic therapy was administered to patients five days a week, with one session per day of 40 min, plus 20 min for preparation
Inclusion criteria were single stroke confirmed by brain imaging (CT or MRI); chronic stroke; ability to understand and the instructions given by doctors and therapists (Mini Mental State Evaluation MMSE ≥ 24); Modified Ashworth

Summary

Introduction

In the past two decades, the numbers and types of commercial robots used in rehabilitation have increased [1]. Robot-assisted rehabilitation may help to improve arm functions, arm muscle strength and activities of daily living. Robots for neurorehabilitation should be divided into exoskeleton and end-effectors, with different devices providing different sets of rehabilitation exercises that might involve different neural mechanisms of plasticity-dependent recovery [1]. There are devices providing passive movements of the patient’s arm [3], assisting voluntary arm movements or providing resistance during training [4], and assisting active movements of an isolated joint, while other devices move multiple segments [5]. The progression of therapy with robotic devices has been continuously adapted by varying the guidance force, decreasing assistance, increasing resistance, expanding the movement amplitude, and increasing the quantity of volitional movement [2]

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