Performance adaptive training control strategy for recovering wrist movements in stroke patients: a preliminary, feasibility study

Abstract

BackgroundIn the last two decades robot training in neuromotor rehabilitation was mainly focused on shoulder-elbow movements. Few devices were designed and clinically tested for training coordinated movements of the wrist, which are crucial for achieving even the basic level of motor competence that is necessary for carrying out ADLs (activities of daily life). Moreover, most systems of robot therapy use point-to-point reaching movements which tend to emphasize the pathological tendency of stroke patients to break down goal-directed movements into a number of jerky sub-movements. For this reason we designed a wrist robot with a range of motion comparable to that of normal subjects and implemented a self-adapting training protocol for tracking smoothly moving targets in order to facilitate the emergence of smoothness in the motor control patterns and maximize the recovery of the normal RoM (range of motion) of the different DoFs (degrees of Freedom).MethodsThe IIT-wrist robot is a 3 DoFs light exoskeleton device, with direct-drive of each DoF and a human-like range of motion for Flexion/Extension (FE), Abduction/Adduction (AA) and Pronation/Supination (PS). Subjects were asked to track a variable-frequency oscillating target using only one wrist DoF at time, in such a way to carry out a progressive splinting therapy. The RoM of each DoF was angularly scanned in a staircase-like fashion, from the "easier" to the "more difficult" angular position. An Adaptive Controller evaluated online performance parameters and modulated both the assistance and the difficulty of the task in order to facilitate smoother and more precise motor command patterns.ResultsThree stroke subjects volunteered to participate in a preliminary test session aimed at verify the acceptability of the device and the feasibility of the designed protocol. All of them were able to perform the required task. The wrist active RoM of motion was evaluated for each patient at the beginning and at the end of the test therapy session and the results suggest a positive trend.ConclusionThe positive outcomes of the preliminary tests motivate the planning of a clinical trial and provide experimental evidence for defining appropriate inclusion/exclusion criteria.

A Pilot Study on the Feasibility of Robot-Aided Leg Motor Training to Facilitate Active Participation

“…Because neuroplasticity is critical for recovery after a neurological injury, it has been suggested that the same mechanisms underlying motor learning may also contribute to motor recovery after injury [28], [29]. Although the concept of motor learning and its importance to motor recovery has been well studied in the upper extremity [30], [31], [32], [33], [34], this has been relatively overlooked in the lower extremity. This could be possibly due to the fact that walking is considered to be an automatic activity, essentially requiring little cognitive effort [35].…”

A Comparative Analysis of Speed Profile Models for Wrist Pointing Movements

“…While these devices mainly target motor therapy at the shoulder and elbow joints, it has long been known that improvements observed at these joints do not generalize to wrist and hand [12]. To overcome this limitation, several wrist devices have been proposed in the last few years, including the MIT wrist robot [13], RiceWrist [14], HWARD [15], the Okayama University pneumatic manipulator [16], and the IIT wrist robot [17]. These robots can be used either as standalone therapy devices for wrist rehabilitation or coupled with other devices such as MIT-MANUS [18], ARMIN [19], HapticMaster [20], and wire-based device from [21] to deliver robot therapy to the whole upper limb.…”

Current Trends in Robot-Assisted Upper-Limb Stroke Rehabilitation: Promoting Patient Engagement in Therapy

“…Masia et al [64] asked subjects to track a target moving in a sinusoidal pattern with wrist movement, and increased the required range of motion after each successful trial. Their preliminary results with three stroke subjects showed the potential of this method to increase subjects’ range of wrist motion.…”