An EMG-to-Force Processing Approach to Estimating Knee Muscle Forces during Adult, Self-Selected Speed Gait.

Background: The purpose of this study was to determine the force production during self-selected speed normal gait by muscle-tendon units that cross the knee. The force of a single knee muscle is not directly measurable without invasive methods, yet invasive techniques are not appropriate for clinical use. Thus, an EMG-to-force processing (EFP) model was developed which scaled muscle-tendon unit (MTU) force output to gait EMG.

Estimates of individual muscle power production in normal adult walking.

Background: The purpose of this study was to determine the contribution of individual hip muscles to the net hip power in normal adult self-selected speed walking. A further goal was to examine each muscle's role in propulsion or support of the body during that task.

Methods: An EMG-to-force processing (EFP) model was developed which scaled muscle-tendon unit (MTU) force output to gait EMG.

An EMG-to-Force Processing approach for estimating in vivo hip muscle forces in normal human walking.

The force of a single muscle is not directly measurable without invasive methods. Yet invasive techniques are not appropriate for clinical use, thus a non-invasive technique that combined the electromyographic (EMG) signal and a neuromuscular model was developed to determine in vivo active muscle forces at the hip. The EMG-to-force processing (EFP) model included active and passive moment components, and the net EFP moment was compared with the hip moment obtained with standard inverse dynamics techniques ("gold standard").

Treatment of severe hand impairment following stroke by combining assisted movement, muscle vibration, and biofeedback.

Background And Purpose: Few studies have addressed the rehabilitation of hand function in persons with severe impairment following stroke, and few therapeutic options are available for treatment. We investigated whether an intervention of robot-assisted movement and muscle vibration could reduce impairment and enable hand-opening to a greater extent when combined with torque biofeedback or electromyographic (EMG) biofeedback.

Methods: Forty-three participants with severe hand impairment due to chronic stroke (≥1 year poststroke) were randomized to 1 of 2 treatment groups receiving assisted movement and muscle vibration combined with either torque or EMG biofeedback.

Error augmentation enhancing arm recovery in individuals with chronic stroke: a randomized crossover design.

Background: Neurorehabilitation studies suggest that manipulation of error signals during practice can stimulate improvement in coordination after stroke.

Objective: To test visual display and robotic technology that delivers augmented error signals during training, in participants with stroke.

Methods: A total of 26 participants with chronic hemiparesis were trained with haptic (via robot-rendered forces) and graphic (via a virtual environment) distortions to amplify upper-extremity (UE) tracking error.

Mapping the neglected space: gradients of detection revealed by virtual reality.

Background: Spatial neglect affects perception along different dimensions. However, there is limited availability of 3-dimensional (3D) methods that fully map out a patient's volume of deficit, although this could guide clinical management.

Objective: To test whether patients with neglect exhibit simple contralesional versus complex perceptual deficits and whether deficits are best described using Cartesian (rectangular) or polar coordinates.

Use of visual force feedback to improve digit force direction during pinch grip in persons with stroke: a pilot study.

Objective: To investigate whether visual feedback of digit force directions for the index fingertip and thumb tip during repeated practice of grip force production can correct the digit force directions for persons with stroke during grip assessments. Following stroke, the paretic fingers generate digit forces with a higher than normal proportion of shear force to compression force during grip. This misdirected digit force may lead to finger-object slip and failure to stably grasp an object.

Effect of a serotonin antagonist on delay in grip muscle relaxation for persons with chronic hemiparetic stroke.

Objective: To investigate if, following stroke, sustained involuntary activity after voluntary contraction (e.g., grip) of the long finger flexor muscles of the paretic hand is attributable to augmented serotonin release from brainstem pathways, affecting excitability of spastic motoneurons.

Determination of ankle muscle power in normal gait using an EMG-to-force processing approach.

The purpose of this study was to determine the contribution of individual ankle muscles to the net ankle power and to examine each muscle's role in propulsion or support of the body during normal, self-selected-speed walking. An EMG-to-force processing (EFP) model was developed which scaled muscle tendon unit force output to gait EMG, with that muscle's power output being the product of muscle force and contraction velocity. Net EFP power was determined by summing individual ankle muscle power.

Gait training strategies utilized in poststroke rehabilitation: are we really making a difference?

Stroke is the leading cause of disability in the United States. Restoration of walking continues to be a major goal of rehabilitation for persons with stroke. The concept of a minimal change in performance to be considered important or significant has recently been addressed in the field of stroke rehabilitation.

An EMG-to-force processing approach for determining ankle muscle forces during normal human gait.

Muscle forces move our limbs. These forces must be estimated with indirect techniques, as direct measurements are neither generally possible nor practical. An electromyography (EMG)-to-force processing technique was developed.

Rehabilitation of movement disorders.

Unlabelled: This self-directed learning module highlights several movement disorders. These include dystonia, chorea, tremors, and myoclonus. A description of the clinical presentation and associated disease processes is presented.

Stroke and neurodegenerative disorders. 4. Neurodegenerative disorders.

Unlabelled: This self-directed learning module highlights diagnosis, treatment, and rehabilitation issues in patients with neurodegenerative disorders, including multiple sclerosis (MS), Parkinson's disease, and amyotrophic lateral sclerosis (ALS). It is part of the study guide on stroke and neurodegenerative disorders in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article specifically focuses on the differential diagnosis, diagnostic evaluation, medical management, and rehabilitation issues in MS.

Stroke and neurodegenerative disorders. 3. Stroke: rehabilitation management.

Unlabelled: This self-directed learning module highlights common rehabilitation issues in stroke survivors. Topics include spasticity, constraint-induced movement therapy, partial body weight-supported treadmill training, virtual reality training, vestibular retraining, aphasia treatment, and cognitive retraining. It is part of the study chapter on stroke and neurodegenerative disorders in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation.

Stroke and neurodegenerative disorders. 2. Stroke: comorbidities and complications.

Unlabelled: This self-directed learning module highlights diagnosis and treatment of comorbidities and complications encountered by patients with stroke. It is part of the study guide on stroke and neurodegenerative disorders in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article specifically focuses on cardiopulmonary complications and examines neurologic sequelae, risk factors for falls, and prevention strategies.

Stroke and neurodegenerative disorders. 1. Acute stroke evaluation, management, risks, prevention, and prognosis.

Unlabelled: This self-directed learning module highlights recent developments in the acute care of stroke patients, prediction of outcome after stroke, evaluation of risk factors, secondary prevention of stroke, and the evaluation of the young adult with stroke. It is part of the study guide on stroke and neurodegenerative disorders in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article contains sections on the acute evaluation and management of the stroke patient, prediction of functional outcome after stroke, and secondary prevention of stroke.

Repeatability of wire and surface electrodes in gait.

Objective: Muscle forces are not directly measurable without invasive methods (i.e., tendon force transducers).

The Rancho EMG analyzer: a computerized system for gait analysis.

This paper describes a computer system which accurately defines the EMG patterns of the lower extremities during gait. Footswitches are used to identify the temporal relationships and determine the phases of the gait cycle. Fine wire electrodes, inserted in the desired muscles of the patient being tested, provide EMG signals for comparison with a normal database.

A computer algorithm for defining the group electromyographic profile from individual gait profiles.

A computer algorithm was developed to determine the group electromyographic (EMG) profile for the soleus muscle during free speed level walking. Subjects consisted of 50 adults (21 male, 29 female) with no history of musculoskeletal disease. EMG was recorded from the soleus muscle with wire electrodes, and was normalized by maximum muscle test.

Computer algorithms to characterize individual subject EMG profiles during gait.

Three methods of precisely determining onset and cessation times of gait EMG were investigated. Subjects were 24 normal adults and 32 individuals with gait pathologies. Soleus muscle EMG during free speed level walking was obtained with fine wires, and was normalized by manual muscle test (%MMT).

Heterogeneous mechanical response of rat knee menisci to thermomechanical stress.

Thermodilatometric, dynamic thermomechanical, and light-microscopic analyses were done on the anterior and posterior regions of the rat knee menisci to correlate regional differences in morphology and extracellular matrix composition with regional mechanical behavior. Following the administration of a general anesthetic, menisci were excised from 12 young female Sprague-Dawley rats. During thermodilatometric and thermomechanical testing, tissue temperature was increased at a constant rate of 3.