Humans have a remarkable ability to create stable walking patterns that can resist and recover from perturbations. Unfortunately, this ability is substantially impaired after a stroke, limiting mobility and contributing to a high fall rate. To facilitate gait training during post-stroke rehabilitation, clinicians often incorporate body-weight support (BWS) systems that...
Coordinated movement relies on the precise and controlled activation of populations of motor units, which convert the commands of the nervous system into muscle forces. Motor unit firing patterns are often nonlinear and generated through the response to a combination of ionotropic excitatory and inhibitory commands, as well as metabotropic...
Stroke affects millions of people each year and although modern medicine has improved chances of survival after stroke, it has not yet been able to affect a change in repairing damaged neural tissue leaving one to two-thirds of survivors with chronic disability in their affected upper-extremity; specifically, hemiparesis, hypertonicity, loss...
The dynamics of human joints are fundamental characteristic of the human motor system, and altered joint impedance can hinder mobility. Individuals with transtibial amputation typically experience slower and energetically costly gait, while individuals with chronic stroke experience persisting gait deficits arising from spasticity, hypertonia and paresis. Investigating joint impedance of...
A stroke occurs when blood flow in the brain is impaired and often causes damage to corticospinal tract projections that control the muscles of the upper-extremity. Due to this damage, 50-70% of stroke survivors experience long-term upper-extremity functional deficits(Faria-Fortini, Michaelsen, Cassiano, & Teixeira-Salmela, 2011). These deficits result from motor impairments...
Motor planning is fundamental to the performance of everyday reaching movements. The influence of planning is not limited to voluntary movements but extends to involuntary movements initiated in response to sensory stimuli, such as postural perturbations applied to the arm. Stroke alters voluntary reaching and the involuntary response to perturbations,...
Individuals following a stroke suffer from a host of movement impairments that affect the upper extremity. Hand use is often significantly compromised, especially in individuals with more severe impairments, which makes it difficult for individuals to participate in activities of daily living. One of the major goals of rehabilitation is...
Up to two thirds of individuals with chronic hemiparetic stroke suffer life-long residual impairments to their paretic hands, affecting their independence and quality of life. These impairments stem initially from losses of direct corticospinal projections that result in an increased reliance on indirect bulbospinal pathways. This reliance on the indirect...
Many stroke survivors are left with residual movement impairments. Treating these impairments has proven difficult, because it is often unclear which mechanisms drive movement impairment. While the exact mechanisms are still uncertain, at present, evidence suggests that neuromuscular function is disrupted in two key domains following stroke: muscle biomechanics, and...