FES Coupled With A Powered Exoskeleton For Cooperative Muscle Contribution In Persons With Paraplegia.

This paper describes the effects of a novel functional electrical stimulation (FES) system which has been integrated in a powered exoskeleton to provide up to 10 channels of stimulation to users with paraplegia via surface electrodes. Experimental data collected from three users with spinal cord injury (SCI) indicate the system reduced the exoskeleton motor torques necessary to perform sit-to-stand transitions in the exoskeleton. All subjects exhibited reduced muscle spasticity immediately after walking in the exoskeleton with FES. Additionally, one subject with stretch-reflex spasms exhibited increased joint excursion and reduced exoskeleton motor torques required to achieve over-ground gait when FES was incorporated.

A systematic review and meta-analysis of quality of life outcomes after radical cystectomy for bladder cancer.

BACKGROUND: Radical cystectomy and urinary diversion is the treatment of choice for invasive bladder cancer. Quality of life (QOL) is an important outcome of surgery. This review compares the QOL after continent and incontinent urinary diversion in radical cystectomy for patients with primary invasive bladder cancer. METHODS: A systematic review and meta-analysis of clinical studies published after January 2000 was performed according to the PRISMA guidelines. Quality appraisal and data tabulation were performed using pre-determined forms. Data were synthesised by narrative review and random-effects meta-analysis using standardized response means. Heterogeneity and bias was assessed by Tau(2) and I(2) values and Funnel plots. RESULTS: Twenty-nine studies (3754 patients) were included for review. Pooled post-operative FACT and SF-36 scores showed no difference in overall QOL between continent and incontinent diversion (p = 0.31). Subgroup analysis demonstrated greater improvement in physical health for incontinent (p = 0.002) compared to continent diversions, but no differences in mental health (p = 0.35) and social health (p = 0.81). Qualitative analysis showed patients with neobladder had superior emotional function and body image compared to cutaneous diversion. QOL may improve to similar or better levels compared to baseline after 1 year, but data remains scarce. Patients report poor urinary and sexual function after surgery compared the general population. Long-term QOL is unclear. Levels of heterogeneity and bias were low. CONCLUSIONS: QOL after radical cystectomy is comparable after either continent or incontinent urinary diversion. Post-operative QOL may improve, but urinary and sexual dysfunction remains inferior to the general population. Patient choice is key to selection of reconstruction method.

An Approach for the Cooperative Control of FES With a Powered Exoskeleton During Level Walking for Persons With Paraplegia.

This paper describes a hybrid system that combines a powered lower limb exoskeleton with functional electrical stimulation (FES) for gait restoration in persons with paraplegia. The general control structure consists of two control loops: a motor control loop, which utilizes joint angle feedback control to control the output of the joint motor to track the desired joint trajectories, and a muscle control loop, which utilizes joint torque profiles from previous steps to shape the muscle stimulation profile for the subsequent step in order to minimize the motor torque contribution required for joint angle trajectory tracking. The implementation described here incorporates stimulation of the hamstrings and quadriceps muscles, such that the hip joints are actuated by the combination of hip motors and the hamstrings, and the knee joints are actuated by the combination of knee motors and the quadriceps. In order to demonstrate efficacy, the control approach was implemented on three paraplegic subjects with motor complete spinal cord injuries ranging from levels T6 to T10. Experimental data indicates that the cooperative control system provided consistent and repeatable gait motions and reduced the torque and power output required from the hip and knee motors of the exoskeleton compared to walking without FES.

An analysis of physiological signals as a measure of task engagement in a multi-limb-coordination motor-learning task.

There is widespread agreement in the physical rehabilitation community that task engagement is essential to effective neuromuscular recovery. Despite this, there are no clear measures of such task engagement. This paper assesses the extent to which certain physiological measurements might provide a measure of task engagement. In previous studies, correlations between mental focus and certain physiological measurements have been observed in subjects performing tasks requiring mental effort. In this study, the authors analyzed whether these signals showed similar correlation when subjects performed a multi-limb-coordination motor-learning task. Subjects played a video game which required the use of both arms and one leg to play a simplified electronic drum set with varying difficulty. Heart rate (HR), skin conductance level (SCL), and facial electromyogram (EMG) were recorded while the subjects played. Analysis of the recordings showed statistically significant correlations relating task difficulty to SCL, HR and EMG amplitude in corrugator supercilii. No statistically significant correlation was observed between task difficulty and EMG in frontalis.

Preliminary assessment of variable geometry stair ascent and descent with a powered lower limb orthosis for individuals with paraplegia.

This paper describes a controller for a lower-limb exoskeleton that enables variable-geometry stair ascent and descent for persons with lower limb paralysis. The controller was evaluated on a subject with T10 complete spinal cord injury (SCI) on two staircases, one with a riser height and tread depth of 18.4 × 27.9 cm (7.25 × 11 in) and the other 17.8 × 29.8 cm (7 × 11.75 in). The controller enabled ascent and descent of both staircases without explicit tuning for each, and with an average step rate of 12.9 step/min during ascent and 14.6 step/min during descent.

An assistive control approach for a lower-limb exoskeleton to facilitate recovery of walking following stroke.

This paper presents a control approach for a lower-limb exoskeleton intended to facilitate recovery of walking in individuals with lower-extremity hemiparesis after stroke. The authors hypothesize that such recovery is facilitated by allowing the patient rather than the exoskeleton to provide movement coordination. As such, an assistive controller that provides walking assistance without dictating the spatiotemporal nature of joint movement is described here. Following a description of the control laws and finite state structure of the controller, the authors present the results of an experimental implementation and preliminary validation of the control approach, in which the control architecture was implemented on a lower limb exoskeleton, and the exoskeleton implemented in an experimental protocol on three subjects with hemiparesis following stroke. In a series of sessions in which each patient used the exoskeleton, all patients showed substantial single-session improvements in all measured gait outcomes, presumably as a result of using the assistive controller and exoskeleton.

A preliminary assessment of legged mobility provided by a lower limb exoskeleton for persons with paraplegia.

This paper presents an assessment of a lower limb exoskeleton for providing legged mobility to people with paraplegia. In particular, the paper presents a single-subject case study comparing legged locomotion using the exoskeleton to locomotion using knee-ankle-foot orthoses (KAFOs) on a subject with a T10 motor and sensory complete injury. The assessment utilizes three assessment instruments to characterize legged mobility, which are the timed up-and-go test, the Ten-Meter Walk Test (10 MWT), and the Six-Minute Walk Test (6 MWT), which collectively assess the subject's ability to stand, walk, turn, and sit. The exertion associated with each assessment instrument was assessed using the Physiological Cost Index. Results indicate that the subject was able to perform the respective assessment instruments 25%, 70%, and 80% faster with the exoskeleton relative to the KAFOs for the timed up-and-go test, the 10 MWT, and the 6 MWT, respectively. Measurements of exertion indicate that the exoskeleton requires 1.6, 5.2, and 3.2 times less exertion than the KAFOs for each respective assessment instrument. The results indicate that the enhancement in speed and reduction in exertion are more significant during walking than during gait transitions.

An assistive controller for a lower-limb exoskeleton for rehabilitation after stroke, and preliminary assessment thereof.

This paper describes a novel controller, intended for use in a lower-limb exoskeleton, to aid gait rehabilitation in patients with hemiparesis after stroke. The controller makes use of gravity compensation, feedforward movement assistance, and reinforcement of isometric joint torques to achieve assistance without dictating the spatiotemporal nature of joint movement. The patient is allowed to self-select walking speed and is able to make trajectory adaptations to maintain balance without interference from the controller. The governing equations and the finite state machine which comprise the system are described herein. The control architecture was implemented in a lower-limb exoskeleton and a preliminary experimental assessment was conducted in which a patient with hemiparesis resulting from stroke walked with assistance from the exoskeleton. The patient exhibited improvements in fast gait speed, step length asymmetry, and stride length in each session, as measured before and after exoskeleton training, presumably as a result of using the exoskeleton.

Patients' perception of surgical training in private hospitals.

INTRODUCTION: Surgical training is traditionally a public hospital-based practice. At Epworth Private Hospital, Richmond, Victoria, there are three accredited surgical training positions and one fellowship position. We conducted a patient survey to review the patients' perspective of surgical trainees in private hospitals. METHODS: Over 6 weeks, 100 patients admitted under the surgical units with full-time surgical registrars were given a survey to complete in two parts on the training of surgeons in private hospitals. RESULTS: Seventy per cent of surveys were returned completed. Ninety per cent of respondents agreed that private hospitals should be involved in surgical training and 85.7% of patients were agreeable to having trainees involved in their operation. Only 1.4% of patients were not in agreement with surgical training in private and 8.6% of patients were neutral in their opinion. CONCLUSION: Our results clearly show that private hospital patients are generally favourably disposed to the presence and participation of surgical trainees in the private hospital setting.

Towards the use of a lower limb exoskeleton for locomotion assistance in individuals with neuromuscular locomotor deficits.

The authors intend to utilize a lower limb exoskeleton for gait assistance in individuals with lower limb neuromuscular deficit. The authors suggest that two foundational elements are required to do so effectively. First, the exoskeleton system must be capable of reliable real-time gait phase detection, in order to determine the nature of gait assistance to provide. Second, in gait phases or circumstances in which the exoskeleton provides minimal assistance, the passive dynamics of the exoskeleton should not hinder the individual (i.e., should have the capability to minimally interfere with gait dynamics). As such, the exoskeleton system should be capable of actively compensating for its passive dynamics, namely the inertial, gravitational, and frictional effects it imposes on the user. This paper describes the implementation of these two foundational elements (real-time gait phase detection and active cancellation of passive dynamics) on a prototype lower limb exoskeleton, and provides experimental data demonstrating their respective efficacy.