T. Adam Thrasher

Rehabilitation of Reaching and Grasping Function in Severe Hemiplegic Patients Using Functional Electrical Stimulation Therapy

Objective. The aim of this study was to establish the efficacy of a therapeutic intervention based on functional electrical stimulation (FES) therapy to improve reaching and grasping function after severe hemiplegia due to stroke. Methods. A total of 21 subjects with acute stroke were randomized into 2 groups, FES plus conventional occupational and physiotherapy (FES group) or only conventional therapy (control group) 5 days a week for 12 to 16 weeks. A third group of 7 subjects with chronic hemiplegia (at least 5 months poststroke) received only FES therapy (chronic group) and pre—post training changes were compared. FES was applied to proximal and then distal muscle groups during specific motor tasks. At baseline and at the end of treatment, grasping function was assessed using the Rehabilitation Engineering Laboratory Hand Function Test, along with more standard measures of rehabilitation outcome. Results. The FES group improved significantly more than the control group in terms of object manipulation, palmar grip torque, pinch grip pulling force, Barthel Index, Upper Extremity Fugl—Meyer scores, and Upper Extremity Chedoke—McMaster Stages of Motor Recovery. The chronic stroke subjects demonstrated improvements in most categories, but the changes were not statistically significant. Conclusions. FES therapy with upper extremity training may be an efficacious intervention in the rehabilitation of reaching and grasping function during acute stroke rehabilitation.

Robot-Assisted Gait Training for Patients with Hemiparesis Due to Stroke

Abstract Robot-assisted devices are becoming a popular alternative to manual facilitation in stroke rehabilitation. These devices have the potential to reduce therapist burden and treatment costs; however, their effectiveness in terms of functional recovery remains in question. This pilot study compared the outcomes of a stroke rehabilitation program that incorporates robot-assisted gait training (RAGT) with a more traditional therapy program that does not. Twenty hemiparetic stroke patients were recruited at a rehabilitation hospital in Houston, Texas, and were randomly assigned to 2 groups. The control group (n = 10) received 24 1-hour sessions of conventional physical therapy, whereas the RAGT group (n = 10) received 24 1-hour sessions of conventional physical therapy combined with RAGT on a treadmill. Gait function was assessed before and after treatment by an 8-m walk test, a 3-minute walk test, and the Tinetti balance assessment. Both groups showed significant improvement in all 3 outcome measures following treatment (P < .05), but there was no difference between groups. It is concluded that RAGT may provide improvements in balance and gait comparable with conventional physical therapy. A larger multicenter trial is required to investigate the effectiveness of RAGT in hemiparetic stroke.

Neuroprosthesis for Retraining Reaching and Grasping Functions in Severe Hemiplegic Patients

During the course of rehabilitation hemiplegic patients who have Chedoke McMaster Stages of Motor Recovery scores 4 and 5 measured three weeks after onset of stroke often improve their arm and hand function to the point that they can later use it in the activities of daily living (ADL) ( 1 ). These patients can be considered to have mild arm and hand paralysis since they can grasp objects and manipulate them with minor restrictions in the range of movement and force. On the other hand, hemiplegic patients who have Chedoke McMaster Stages of Motor Recovery scores 1 and 2 measured three weeks after onset of stroke, during the course of rehabilitation seldom improve their arm and hand function, and when they do, the improvements are not sufficient to allow these patients to use the arm and hand in ADL ( 1 ). These patients can be also described as patients who have severe arm and hand paralysis. Patients with severe arm and hand paralysis cannot move their arm and hand voluntarily at all or have very limited voluntary movements that cannot be used to carry out ADL. In recent years a variety of treatments such as constraint induced therapy, functional electrical therapy, biofeedback therapy, and robotics assisted therapies, were proposed which main objective is to improve reaching and grasping functions in subjects with unilateral arm paralysis. These therapies have shown encouraging results in patients with mild arm and hand paralysis. However, the efficacy of these therapies was limited when they were applied to patients with severe arm and hand paralysis. This article describes a new rehabilitation technique that can improve both reaching and grasping functions in hemiplegic patients with severe unilateral arm paralysis. A neuroprosthesis that applies surface electrical stimulation technology was used to retrain hemiplegic patients who had severe arm and hand paralysis to reach and grasp. The neuroprosthesis was applied both to acute and long‐term hemiplegic patients. Patients who were treated with the neuroprosthesis were compared to those patients who were administered only standard physiotherapy and occupational therapy appropriate for hemiplegic patients with unilateral upper extremity paralysis (controls). The treated and control patients had approximately the same time allocated for arm and hand therapy. After the treatment program was completed, the patients treated with the neuroprosthesis significantly improved their reaching and grasping functions and were able to use them in ADL. However, the majority of the control patients did not improve their arm and hand functions significantly and were not able to use them in ADL.

Postural reactions of the trunk muscles to multi-directional perturbations in sitting

BACKGROUND The dynamic role of the trunk musculature, with respect to stability, has not been fully explored to date. The purpose of this study was, using a transient and multi-directional perturbation, to: (1) quantify the tonic level of activity in the superficial trunk musculature prior to any perturbation; (2) quantify the phasic activity in those same muscles following application of a transient, horizontally directed load; and (3) quantify the direction-dependent behavior of this phasic response. METHODS Twelve healthy individuals were perturbed during sitting via a chest harness in eight horizontal directions. Surface electromyograms were measured bilaterally from the abdominal (rectus abdominis, internal and external obliques) and back musculature (thoracic and lumbar erector spinae) to determine the tonic muscle activity prior to perturbation, and the phasic response following perturbation. A descriptive model was used to characterize the relationship between the phasic response of the muscles due to perturbation and the pulling direction. FINDINGS Tonic activity in the trunk musculature in upright sitting is low, but still above resting levels by at about 1-3% of the MVC for the abdominal muscles, and 4-6% for the back muscles. Each trunk muscle also showed a direction-specific, phasic activation in response to perturbation, above these tonic levels of activation. This phasic activation was accurately modeled using a descriptive model for each muscle. INTERPRETATION The obtained muscle activation level and the identified descriptive model will be applied in the design of a closed-loop controller for functional electrical stimulation.

Cardiovascular response to functional electrical stimulation and dynamic tilt table therapy to improve orthostatic tolerance

Orthostatic hypotension is a common condition for individuals with stroke or spinal cord injury. The inability to regulate the central nervous system will result in pooling of blood in the lower extremities leading to orthostatic intolerance. This study compared the use of functional electrical stimulation (FES) and passive leg movements to improve orthostatic tolerance during head-up tilt. Four trial conditions were assessed during head-up tilt: (1) rest, (2) isometric FES of the hamstring, gastrocnemius and quadriceps muscle group, (3) passive mobilization using the Erigo dynamic tilt table; and (4) dynamic FES (combined 2 and 3). Ten healthy male subjects experienced 70 degrees head-up tilt for 15 min under each trial condition. Heart rate, blood pressure and abdominal echograms of the inferior vena cava were recorded for each trial. Passive mobilization and dynamic FES resulted in an increase in intravascular blood volume, while isometric FES only resulted in elevating heart rate. No significant differences in blood pressure were observed under each condition. We conclude that FES combined with passive stepping movements may be an effective modality to increase circulating blood volume and thereby tolerance to postural hypotension in healthy subjects.

A complete, non-lumped, and verifiable set of upper body segment parameters for three-dimensional dynamic modeling

Dynamic models of the human trunk have been extensively used to investigate the biomechanics of lower back pain and postural instability in different populations. Despite their diverse applications, previous models rely on intrinsic upper body segment parameters (UBSP), e.g., each segments mass-inertia characteristics. However, a comprehensive UBSP set allowing state-of-the-art, three-dimensional (3D) dynamic modeling does not exist to date. Therefore, our objective was to establish a UBSP set of all vertebral trunk segments that is accurate and complete. Based on high-resolution, transverse color images, anatomical structures of the Male Visible Human (MVH) were digitally reconstructed via commercial software. Subsequently, we identified the 3D spinal joint and 3D center of mass coordinates, the mass, and the moment of inertia tensor for 24 vertebral trunk segments and 4 upper limb segments (two segments per arm). Since the MVH images are public domain, the parameters are uniquely verifiable and expandable to also include lower limb parameters. To demonstrate the UBSP sets practicality, the parameters were finally implemented in a previously proposed inverse dynamics model of the upper body. Our findings reveal that an accurate and complete UBSP set has been obtained that will be beneficial to (1) systemize thinking in postural control studies; (2) quantify the effect of impact forces on the head and trunk (e.g., during whiplash); (3) suggest population-specific experiments based on theoretical insights into trunk dynamics (e.g., regarding lower back pain); or (4) assess the feasibility of new surgical techniques (e.g., spinal fusion) and neuroprostheses (e.g., after spinal cord injury).

A comprehensive three-dimensional dynamic model of the human head and trunk for estimating lumbar and cervical joint torques and forces from upper body kinematics.

Linked-segment representations of human body dynamics have been used extensively in biomechanics, ergonomics, and rehabilitation research to systemize thinking, make predictions, and suggest novel experiments. In the scope of upper body biomechanics, these models play an even more essential role as the human spine dynamics are difficult to study in vivo. No study exists to date, however, that specifically disseminates the technical details of a comprehensive three-dimensional model of the upper body for the purpose of estimating spinal joint torques and forces for a wide range of scenarios. Consequently, researchers are still bound to develop and implement their own models. Therefore, the objective of this study was to design a dynamic model of the upper body that can comprehensively estimate spinal joint torques and forces from upper body kinematics. The proposed three-dimensional model focuses on the actions of the lumbar and cervical vertebrae and consists of five lumbar segments (L1 to L5), the thorax, six cervical segments (C2 to C7), and the head. Additionally, the model: (1) is flexible regarding the kinematic nature of the spinal joints (free, constrained, or fixed); (2) incorporates all geometric and mass-inertia parameters from a single, high-resolution source; and (3) can be feasibly implemented via different inverse dynamics formulations. To demonstrate its practicality, the model was finally employed to estimate the lumbar and cervical joint torques during perturbed sitting using experimental motion data. Considering the growing importance of mathematical predictions, the developed model should become an important resource for researchers in different fields.

Exercise Intensity during Treadmill Walking with Gait-Patterned FES among Patients with Incomplete Spinal Cord Injury: Case Series

Purpose. To determine the feasibility of increasing the cardiopulmonary exercise intensity during walking with gait-patterned functional electrical stimulation (GP-FES) among individuals with motor incomplete SCI. Methods. Two men with motor-incomplete SCI (Subjects A and B, age 45 and 50 years; Level of Injury: C4 and T10; AIS score: D and D, resp.) performed a three sequential four-minute continuous walking sessions [(1) regular gait (non-GP-FES-1); (2) gait with GP-FES (GP-FES); (3) regular gait (non-GP-FES-2)]. Oxygen consumption (Vo2) was measured continuously during trials. Results. Vo2 was higher during GP-FES (Subjects A and B; 14.5 and 19.1 mL/kg/min, resp.) as compared to regular gait (Non-GP-FES-1: Subjects A and B; 13.4 and 17.0: mL/kg/min, resp.; non-GP-FES-2: Subjects A and B; 13.1 and 17.5: mL/kg/min, resp.). Conclusion. The exercise intensity of GP-FES walking was higher than that of regular walking among individuals with motor incomplete SCI. Further investigations are required to determine the clinical relevance of the exercise.