Effect of functional electrical stimulation-assisted rowing on cardiorespiratory function in persons with spinal cord injury
People with spinal cord injury (SCI) are at an increased risk of the diseases of inactivity (cardiovascular disease, diabetes, osteoporosis and obesity) compared with their able bodied counterparts. In addition, some of the physiological consequences of SCI (e.g. impaired bladder, bowel and sexual function) result in a reduced quality of life. Improvements in cardiorespiratory fitness are related to a reduced incidence of the diseases of inactivity and an enhanced quality of life in people with SCI. To improve cardiorespiratory fitness an appropriate exercise training programme is required. Such a programme needs to place the cardiorespiratory system under sufficient stress to stimulate adaptation. Neither upper body exercise nor functional electrical stimulation (FES)-assisted cycling appear to provide sufficient physiologic stress to bring about significant improvements in cardiorespiratory fitness.
Hybrid functional electrical stimulation (FES)-assisted exercise systems, which recruit the paralysed lower limbs simultaneous with the voluntary action of the arms, significantly increase the cardiorespiratory demand of exercise. FES-rowing has been shown to elicit a greater acute cardiorespiratory response than any other type of exercise in people with SCI. It is possible, therefore, that people with SCI may derive significant cardiorespiratory benefits from a programme of FES-rowing training.
Studies that have investigated the cardiorespiratory benefits of FES rowing have focused on gross measures of aerobic capacity. Although important, these studies have not examined the effect of FES-rowing upon the physiological systems that underpin changes in cardiorespiratory fitness. Cardiac, vascular and respiratory structure and function may all change in response to a structured programme of FES-rowing. Therefore, the purpose of the present study is to determine how the physiologic systems underpinning cardiorespiratory fitness and quality of life adapt in response to a programme of FES-rowing. Such information may ultimately provide a basis for using FES-rowing training as an additional therapeutic measure in people with SCI.
The Potential Therapeutic Benefit Of Cortical Repetitive Transcranial Magnetic Stimulation on Pelvic Sphincter “Guarding Reflex” Function To Promote Continence In Incomplete Spinal Cord Injury: A Pilot Study
Bladder and bowel problems continue to be the most troublesome aspects of everyday life for people with paraplegia. Indeed, recent surveys have shown that above all the many other medical conditions in spinal cord injury, the need to continue targeting recovery of bladder, bowel and sexual functions are uppermost in patients’ own desires; this is despite the considerable progress achieved to manage them over the past 60 years. There are a number of treatments to alleviate the bothersome symptoms of urinary and faecal incontinence including drugs, medical devices and surgery, but none are completely satisfactory. Furthermore, the so-called “cure” by nerve regeneration and repair, if it is possible, is now looking likely to require many more years of development . So it is timely to consider some alternative therapies that might be achievable in the shorter-term. One such new therapy could involve tapping into the “plasticity” of surviving nervous pathways in the spinal cord following an injury; pathways that normally control voluntary contractions of the bladder and bowel sphincters that help to maintain continence and achieve voiding.
Recently, our team, at the London Spinal Cord Injuries Centre at Stanmore, together with Imperial College and University College London, has been investigating the integrity and function of any elements of the spinal pathways controlling bladder and bowel sphincters that have survived in people with incomplete spinal cord injuries. When compared to people without an injury we have found, not unexpectedly, that voluntary sphincter contractions are weak, variable and poorly sustained. Interestingly, when we stimulate these residual spinal pathways with a single non-invasive magnetic stimulation pulse to the correct part of the brain we can momentarily enhance reflexes that contract the sphincters, but only to a much lower level as compared with people without a spinal injury. In neither group of people do we observe this enhancing effect lasting longer than a few seconds at most. Clearly such brief interaction does not impact significantly on the plasticity of the brain or spinal cord and provides no lasting functional benefits.
However, studies of limb muscles have shown that by giving bursts of repetitive magnetic transcranial stimulation (known as rTMS) to the brain, the voluntary pathways to muscles can be significantly facilitated and the effects made to persist for up to many hours or even days. We suggest that the potential for extending these persistent effects to bladder and bowel sphincters may well be the basis of a therapy, for example as an adjunct to proven rehabilitation techniques, to improve continence in spinal cord injury. In a small preliminary study on healthy volunteers we have already demonstrated the utility of rTMS for enhancing sphincter reflex function. This application is now for funding a pilot study to investigate, in a randomized scientifically controlled way, whether similar effects can be demonstrated in persons with an incomplete spinal cord injury. If we are successful in this endeavour then we would go on to develop a more comprehensive study to investigate the impact of such important effects on improving continence and voiding in spinal cord injury.