Posts Tagged sensorimotor recovery

[ARTICLE] Personalized upper limb training combined with anodal-tDCS for sensorimotor recovery in spastic hemiparesis: study protocol for a randomized controlled trial – Full Text

Abstract

Background

Recovery of voluntary movement is a main rehabilitation goal. Efforts to identify effective upper limb (UL) interventions after stroke have been unsatisfactory. This study includes personalized impairment-based UL reaching training in virtual reality (VR) combined with non-invasive brain stimulation to enhance motor learning. The approach is guided by limiting reaching training to the angular zone in which active control is preserved (“active control zone”) after identification of a “spasticity zone”. Anodal transcranial direct current stimulation (a-tDCS) is used to facilitate activation of the affected hemisphere and enhance inter-hemispheric balance. The purpose of the study is to investigate the effectiveness of personalized reaching training, with and without a-tDCS, to increase the range of active elbow control and improve UL function.

Methods

This single-blind randomized controlled trial will take place at four academic rehabilitation centers in Canada, India and Israel. The intervention involves 10 days of personalized VR reaching training with both groups receiving the same intensity of treatment. Participants with sub-acute stroke aged 25 to 80 years with elbow spasticity will be randomized to one of three groups: personalized training (reaching within individually determined active control zones) with a-tDCS (group 1) or sham-tDCS (group 2), or non-personalized training (reaching regardless of active control zones) with a-tDCS (group 3). A baseline assessment will be performed at randomization and two follow-up assessments will occur at the end of the intervention and at 1 month post intervention. Main outcomes are elbow-flexor spatial threshold and ratio of spasticity zone to full elbow-extension range. Secondary outcomes include the Modified Ashworth Scale, Fugl-Meyer Assessment, Streamlined Wolf Motor Function Test and UL kinematics during a standardized reach-to-grasp task.

Discussion

This study will provide evidence on the effectiveness of personalized treatment on spasticity and UL motor ability and feasibility of using low-cost interventions in low-to-middle-income countries.

Background

Stroke is a leading cause of long-term disability. Up to 85% of patients with sub-acute stroke present chronic upper limb (UL) sensorimotor deficits [1]. While post-stroke UL recovery has been a major focus of attention, efforts to identify effective rehabilitation interventions have been unsatisfactory. This study focuses on the delivery of personalized impairment-based UL training combined with low-cost state-of-the-art technology (non-invasive brain stimulation and commercially available virtual reality, VR) to enhance motor learning, which is becoming more readily available worldwide.

A major impairment following stroke is spasticity, leading to difficulty in daily activities and reduced quality of life [2]. Studies have identified that spasticity relates to disordered motor control due to deficits in the ability of the central nervous system to regulate motoneuronal thresholds through segmental and descending systems [34]. In the healthy nervous system, the motoneuronal threshold is expressed as the “spatial threshold” (ST) or the specific muscle length/joint angle at which the stretch reflex and other proprioceptive reflexes begin to act [567]. The range of ST regulation in the intact system is defined by the task-specific ability to activate muscles anywhere within the biomechanical joint range of motion (ROM). However, to relax the muscle completely, ST has to be shifted outside of the biomechanical range [8].

After stroke, the ability to regulate STs is impaired [3] such that the upper angular limit of ST regulation occurs within the biomechanical range of the joint resulting in spasticity (spasticity zone). Thus, resistance to stretch of the relaxed muscle has a spatial aspect in that it occurs within the defined spasticity zone. In other joint ranges, spasticity is not present and normal reciprocal muscle activation can occur (active control zone; [4] Fig. 1). This theory-based intervention investigates whether recovery of voluntary movement is linked to recovery of ST control.[…]

Continue —> Personalized upper limb training combined with anodal-tDCS for sensorimotor recovery in spastic hemiparesis: study protocol for a randomized controlled trial | Trials | Full Text

Fig. 3Jintronix virtual reality (VR) games used in the intervention. a Fish Frenzy game requires the player to trace a three-dimensional (3D) trajectory by moving a fish on the screen in different shapes. b Kitchen Cleanup game requires forward reaching towards kitchen cutlery and returning them to shelves and drawers. c Garden Grab game requires lateral reaching while planting seeds, harvesting and transferring tomatoes to baskets. d Catch, Carry, Drop game requires bilateral coordination while catching apples, carrying and dropping them into a container

 

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[ARTICLE] DEVELOPMENT OF A REHABILITATIVE EXOSKELETAL ARM – Full Text HTML/PDF

 

ABSTRACT
Reduced motor capacity of the upper extremities is a common
result of strokes, spinal cord injuries, accidental injuries, and
neurodegenerative diseases. Sensorimotor recovery can be
attained through gradual and repetitive exercises. In recent
years, robot-assisted rehabilitation has been shown to improve
treatment outcomes in these cases. This paper aims to discuss a
potential method of rehabilitation through the use of a robotic
exoskeletal device that is designed to conform to the shape of
an arm. Three different program methods were developed as
modes of exercise and therapy to achieve passive exercise,
assisted motions, and resistive-active exercise.
INTRODUCTION
Reduced motor capacity of the upper extremities is a
common result of strokes, spinal cord injuries, accidental
injuries, and neurodegenerative diseases. Sensorimotor
recovery can be attained through gradual and repetitive
exercises [3-5]. In recent years, robot-assisted rehabilitation has
been shown to improve treatment outcomes in these cases [6-
10].
Current exoskeleton rehabilitative devices have multiple
advantages over traditionally manual techniques, including [2]:
Data tracking for performance feedback
The ability to apply controlled forces at each joint as
well as magnitude adjustment of such forces based on
patient needs
They can be adjusted for multiple limb sizes to fit
different patients
They can replicate the majority of the patients upper
limb healthy workspace, using multiple degrees of
freedom.
This device contains additional advantages over current
devices. First of all it will be portable. It is going to address a
very specific task, which makes it more user friendly, and last
but not least it has a simple and cost effective design.
This bicep & tricep therapeutic device will have three
modes of operation: passive, assisted motions, and resistive-
active. A linear actuator provides the necessary movement of
the exoskeleton and a pair of force sensors tracks the response
of the patient to the therapeutic session. The passive mode is
for patients that have complete muscle atrophy. In this mode
the actuator does all the work to emotionally stimulate the
patient. The assisted motions mode offers the patient force
amplification. This mode allows patients with weak upper
limbs to perform everyday life tasks such as lifting, pushing,
pulling, etc. In this mode, the speed of the actuator is directly
proportional to the force applied by the user. If the patient
applies a higher force, the actuator moves faster, and vice versa.
In the resistive-active mode, the user must apply a load on the
load sensor that surpasses a certain threshold. When the robot
detects this, it moves the actuator at a speed that creates
resistance for the user. In this mode, if the load applied by the
user falls below the threshold, the actuator stops.

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[ARTICLE] A review of transcranial magnetic stimulation and multimodal neuroimaging to characterize post-stroke neuroplasticity – Full Text PDF

Abstract:

Following stroke, the brain undergoes various stages of recovery where the central nervous system can reorganize neural circuitry (neuroplasticity) both spontaneously and with the aid of behavioural rehabilitation and non-invasive brain stimulation. Multiple neuroimaging techniques can characterize common structural and functional stroke-related deficits, and importantly, help predict recovery of function. Diffusion tensor imaging (DTI) typically reveals increased overall diffusivity throughout the brain following stroke, and is capable of indexing the extent of white matter damage. Magnetic resonance spectroscopy (MRS) provides an index of metabolic changes in surviving neural tissue after stroke, serving as a marker of brain function. The neural correlates of altered brain activity after stroke have been demonstrated by abnormal activation of sensorimotor cortices during task performance, and at rest, using functional magnetic resonance imaging (fMRI). Electroencephalography (EEG) has been used to characterize motor dysfunction in terms of increased cortical amplitude in the sensorimotor regions when performing upper-limb movement, indicating abnormally increased cognitive effort and planning in individuals with stroke. Transcranial magnetic stimulation (TMS) work reveals changes in ipsilesional and contralesional cortical excitability in the sensorimotor cortices. The severity of motor deficits indexed using TMS has been linked to the magnitude of activity imbalance between the sensorimotor cortices.

In this paper we will provide a narrative review of data from studies utilizing DTI, MRS, fMRI, EEG and brain stimulation techniques focusing on TMS and its combination with uni and multi-modal neuroimaging methods to assess recovery after stroke. Approaches that delineate the best measures with which to predict or positively alter outcomes will be highlighted.

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