Ankle-Foot-Orthosis “Hermes” Compensates Pathological Ankle Stiffness of Chronic Stroke—A Proof of Concept

Individuals with an upper motor neuron syndrome, e.g., stroke survivors, may have a pathological increase of passive ankle stiffness due to spasticity, that impairs ankle function and activities such as walking. To improve mobility, walking aids such as ankle-foot orthoses and orthopaedic shoes are prescribed. However, these walking aids...

Mild Stroke, Serious Problems: Limitations in Balance and Gait Capacity and the Impact on Fall Rate, and Physical Activity

Background: After mild stroke persistent balance limitations may occur, creating a risk factor for fear of falling, falls, and reduced activity levels. Objective. To investigate whether individuals in the chronic phase after mild stroke show balance and gait limitations, elevated fall risk, reduced balance confidence, and physical activity...

Development of the Balance module to support stroke patients during treadmill-based gait rehabilitation training

After a stroke, patients often need gait rehabilitation training to regain a safe walking pattern to participate in daily activities again. Good gait rehabilitation training comprises high intensity, which can be achieved using support systems, such as treadmills. Research pointed out that there are insufficient support systems for patients with...

NeuroControl of movement: System identification approach for clinical benefit

Progress in diagnosis and treatment of movement disorders after neurological diseases like stroke, cerebral palsy (CP), dystonia and at old age requires understanding of the altered capacity to adequately respond to physical obstacles in the environment. With posture and movement disorders, the control of muscles is hampered, resulting in...

Quantifying neuromechanical parameters during a robot assisted visuomotor tracking task

In the field of neurorehabilitation, robots are being used to provide assisting forces for therapeutic purposes, and with system identification & parameter estimation (SIPE) methods they are used to quantify neuromechanical parameters for diagnostic purposes. To better understand the beneficial effect of robotic assistance on the neuromechanical...

Comprehensive neuromechanical assessment in stroke patients: Reliability and responsiveness of a protocol to measure neural and non-neural wrist properties

Background: Understanding movement disorder after stroke and providing targeted treatment for post stroke patients requires valid and reliable identification of biomechanical (passive) and neural (active and reflexive) contributors. Aim of this study was to assess test-retest reliability of passive, active and reflexive parameters and to...

Quantifying Bilateral Coupling in Wrist Motor Control

Bilateral coupling, the synchronized behavior between the upper limbs in time and direction, is a well known movement phenomenon for babies. After the age of 11 months, this coupling is largely inhibited so that each limb can be coordinated individually. For stroke patients however, bilateral coupling tends to return. The goal of this study is...

Control of thumb force using surface functional electrical stimulation and muscle load sharing

Background Stroke survivors often have difficulties in manipulating objects with their affected hand. Thumb control plays an important role in object manipulation. Surface functional electrical stimulation (FES) can assist movement. We aim to control the 2D thumb force by predicting the sum of individual muscle forces, described by a sigmoidal...

Identification of Muscle Activation at Rest

Offset muscle activation is the constant neural firing to muscles, even at rest, defining the minimum muscle contraction. Until now, the offset muscle activation has been neglected in the analysis of the dynamical behavior of joints. There is a clinical need for an assessment method to estimate the contribution of the offset muscle activation to...

Selective control of gait subtasks in robotic gait training: Foot clearance support in stroke survivors with a powered exoskeleton

Background Robot-aided gait training is an emerging clinical tool for gait rehabilitation of neurological patients. This paper deals with a novel method of offering gait assistance, using an impedance controlled exoskeleton (LOPES). The provided assistance is based on a recent finding that, in the control of walking, different modules can be...

The gap between clinical gaze and systematic assessment of movement disorders after stroke

Background: Movement disorders after stroke are still captured by clinical gaze and translated to ordinal scores of low resolution. There is a clear need for objective quantification, with outcome measures related to pathophysiological background. Neural and non-neural contributors to joint behavior should be separated using different...

The effect of ankle foot orthosis stiffness on the energy cost of walking: A simulation study

Background In stroke and multiple sclerosis patients, gait is frequently hampered by a reduced ability to push-off with the ankle caused by weakness of the plantar-flexor muscles. To enhance ankle push-off and to decrease the high energy cost of walking, spring-like carbon-composite Ankle Foot Orthoses are frequently prescribed. However, it is...

Poor motor function is associated with reduced sensory processing after stroke

Abstract The possibility to regain motor function after stroke depends on the intactness of motor and sensory pathways. In this study, we evaluated afferent sensory pathway information transfer and processing after stroke with the coherence between cortical activity and a position perturbation (position-cortical coherence, PCC). Eleven subacute...