Ian Swain

Biomechanical approaches applied to the lower and upper limb for the measurement of spasticity: a systematic review of the literature.

Purpose: To review and characterise biomechanical approaches for the measurement of spasticity as one component of the upper motor neurone syndrome. Method: Systematic literature searches based on defined constructs and a four-step review process of approaches used or described to measure spasticity, its association with function or associated phenomena. Most approaches were limited to individual joints and therefore, to reflect this trend, references were grouped according to which body joint(s) were investigated or whether it addressed a functional activity. For each joint, references were further sub-divided into the types of measurement method described. Results: A database of 335 references was established for the review process. The knee, ankle and elbow joints were the most popular, perhaps reflecting the assumption that they are mono-planar in movement and therefore simpler to assess. Seven measurement methods were identified: five involving passive movement (manual, controlled displacement, controlled torque, gravitational and tendon tap) and two involving active movement (voluntary and functional). Generally, the equipment described was in an experimental stage and there was a lack of information on system properties, such as accuracy or reliability. Patient testing was either by cohort or case studies. The review also conveyed the myriad of interpretations of the concept of spasticity. Conclusions: Though biomechanical approaches provide quantitative data, the review highlighted several limitations that have prevented them being established as an appropriate method for clinical application to measure spasticity.

Limb blood flow, cardiac output and quadriceps muscle bulk following spinal cord injury and the effect of training for the Odstock functional electrical stimulation standing system

As part of the assessment of the Odstock functional electrical stimulation (FES) standing system for mid to low thoracic lesion spinal cord injured (SCI) subjects, cardiac output, thigh blood flow and quadriceps muscle thickness were measured before and following an electrical stimulation muscle retraining programme. The same parameters were also measured in a group of uninjured subjects and in SCI subjects. It was found that there was no difference in cardiac output between the groups. However thigh blood flow was found to be around 65% of normal values in the spinally injured group. This returned to normal values following the retraining programme. The quadriceps muscle wasted to approximately 50% of its original thickness in the first 3 weeks following spinal cord injury. The retraining programme increased the muscle thickness to near normal values.

Methods of measuring skin blood flow

This review surveys the methods of assessment of skin blood flow currently in use, examines the different parameters being measured, and comments on their applicability and problems of interpretation. The methods covered include direct capillary pressure measurement; transcutaneous oxygen measurement; radionuclide techniques; temperature techniques (radiometric measurements, thermography, microwave radiometry, thermal clearance or conductivity measurements); ultrasound; dermofluorometry; laser Doppler flowmetry; photoplethysmography; and capillary microscopy.

Control of leg-powered paraplegic cycling using stimulation of the lumbo-sacral anterior spinal nerve roots

We investigated leg-powered cycling in a recumbent tricycle for a paraplegic using functional electrical stimulation (FES) with the lumbo-sacral anterior root stimulator implant (LARSI). A female complete T9 paraplegic had a stimulator for the anterior L2 to S2 spinal roots (bilaterally) implanted in 1994. She was provided with equipment for daily FES cycling exercise at home. The cycling controller applies a pattern of stimulation in each of 16 crank angle phases. A 7-bit shaft encoder measures the crank angle with adequate precision. Each pattern was originally chosen to give the greatest propulsive force in that position when there was no motion. However, dynamically, some reduction in co-contraction is needed; also the patterns are applied with a preset advance time. Maximal power is obtained with an advance of 250 ms, which compensates for muscle response delay and accommodates changes in cadence (from about 25 to 85 rpm). With this system, she has cycled 1.2 km at a time on gently undulating road. We found that spinal root stimulation gives sufficient control over the muscles in the legs to produce a fluid cycling gait. We propose that root stimulation for leg cycling exercise may be a practicable and valuable function for paraplegics following spinal cord injury.

Electrical stimulation of abdominal muscles for control of blood pressure and augmentation of cough in a C3/4 level tetraplegic.

Objectives: Evaluation of a FES (Functional Electrical Stimulation) device for the relief of postural hypertension and augmentation of cough in a C3 ventilator-dependent tetraplegic.Study design: A single case study.Setting: A supra regional spinal unit in the UK.Method: A dual channel stimulator was designed that allowed selection and initiation of two predetermined stimulation intensities using a chin controlled joystick. Two sets of 70 mm diameter electrodes were placed either side of the abdomen. Approximately 80 mA, 300 μs, 40 Hz was required for assisted cough while about 40 mA was required for maintenance of blood pressure. After eating, the lower level stimulus is self-administered every 3 to 5 min gradually increasing the time between groups of burst to once every hour after 90 min.Results: Following eating, a blood pressure of 60/45 mmHg was recorded. After five 1 s bursts of stimulation in quick repetition, this was increased to 133/92 mmHg. After 2 min blood pressure had fallen to 124/86 mmHg and to 93/66 after a further 4 min. The electrical stimulation was then repeated, returning the blood pressure to the previous higher level. Measurement of peak expiratory flow showed an increase from 275 l/min for an unassisted cough to 425 l/min when using the device.Conclusion: The device is used every day. The user is now independent in coughing function and no longer requires suction or manual assistance. Maintenance of blood pressure has significantly improved his quality of life.

The long-term cost-effectiveness of the use of Functional Electrical Stimulation for the correction of dropped foot due to upper motor neuron lesion.

OBJECTIVE Functional Electrical Stimulation (FES) for correction of dropped foot has been shown to increase mobility, reduce the incidence of falls and to improve quality of life. This study aimed to determine how long the intervention is of benefit, and the total cost of its provision. DESIGN Retrospective review of medical records. PARTICIPANTS One hundred and twenty-six people with spastic dropped foot (62 stroke, 39 multiple sclerosis, 7 spinal cord injury, 3 cerebral palsy, 15 others) who began treatment in the year 1999. METHOD All received common peroneal nerve stimulation, producing dorsiflexion and eversion time to the swing phase of gait using a heel switch. Device usage, 10 m walking speed and Functional Walking Category (FWC) were recorded. RESULTS The median time of FES use was 3.6 years (mean 4.9, standard deviation 4.1, 95% confidence interval 4.2-5.6) with 33 people still using FES after a mean of 11.1 years. People with stroke walked a mean of 45% faster overall, including a 24% training effect with 52% improving their FWC. People with multiple sclerosis did not receive a consistent training effect but walked 29% faster when FES was used with 40% increasing their FWC. The average treatment cost was £3,095 per patient resulting in a mean cost per Quality Adjusted Life Years of £15,406. CONCLUSION FES is a practical, long-term and cost-effective treatment for correction of dropped foot.

Assistive technologies after stroke: self-management or fending for yourself? A focus group study

BackgroundAssistive Technologies, defined as “electrical or mechanical devices designed to help people recover movement” have demonstrated clinical benefits in upper-limb stroke rehabilitation. Stroke services are becoming community-based and more reliant on self-management approaches. Assistive technologies could become important tools within self-management, however, in practice, few people currently use assistive technologies. This study investigated patients’, family caregivers and health professionals’ experiences and perceptions of stroke upper-limb rehabilitation and assistive technology use and identified the barriers and facilitators to their use in supporting stroke self-management.MethodsA three-day exhibition of assistive technologies was attended by 204 patients, family caregivers/friends and health professionals. Four focus groups were conducted with people purposively sampled from exhibition attendees. They included i) people with stroke who had used assistive technologies (n = 5), ii) people with stroke who had not used assistive technologies (n = 6), iii) family caregivers (n = 5) and iv) health professionals (n = 6). The audio-taped focus groups were facilitated by a moderator and observer. All participants were asked to discuss experiences, strengths, weaknesses, barriers and facilitators to using assistive technologies. Following transcription, data were analysed using thematic analysis.ResultsAll respondents thought assistive technologies had the potential to support self-management but that this opportunity was currently unrealised. All respondents considered assistive technologies could provide a home-based solution to the need for high intensity upper-limb rehabilitation. All stakeholders also reported significant barriers to assistive technology use, related to i) device design ii) access to assistive technology information and iii) access to assistive technology provision. The lack of and need for a coordinated system for assistive technology provision was apparent. A circular limitation of lack of evidence in clinical settings, lack of funded provision, lack of health professional knowledge about assistive technologies and confidence in prescribing them leading to lack of assistive technology service provision meant that often patients either received no assistive technologies or they and/or their family caregivers liaised directly with manufacturers without any independent expert advice.ConclusionsConsiderable systemic barriers to realising the potential of assistive technologies in upper-limb stroke rehabilitation were reported. Attention needs to be paid to increasing evidence of assistive technology effectiveness and develop clinical service provision. Device manufacturers, researchers, health professionals, service funders and people with stroke and family caregivers need to work creatively and collaboratively to develop new funding models, improve device design and increase knowledge and training in assistive technology use.

The measurement of interface pressure and its role in soft tissue breakdown

This paper describes the effect of applied pressure on soft tissue and its possible role in the development of pressure ulcers. It concentrates on the quantification of the applied pressure at the patient-support interface and the limitations and variability of current techniques, measurement systems and data presentation. It then describes the effects of interface pressures at the tissue and cellular level, and attempts that have been made to describe and model the tissue mechanics. Finally it sets a challenge to medical engineers to improve the present measurement systems and tissue models, thus increasing understanding, both clinically and at the cellular level, so that the incidence of pressure ulcers can be reduced.

Functional electrical stimulation: a review of the literature published on common peroneal nerve stimulation for the correction of dropped foot

A person who has a dropped foot is unable to lift the toes clear of the ground during the swing phase of walking. Such a problem is seen in people who have either a peripheral nerve lesion, as a result of trauma or disease, or an upper motor neuron les ion. It is the latter that responds to neuromuscular stimulation; lesions of the lower motor neurons result in destruction of the neural pathway so that muscle contraction can be achieved only through direct stimulation of the muscle fibres.

Translation of evidence-based Assistive Technologies into stroke rehabilitation: users' perceptions of the barriers and opportunities

BackgroundAssistive Technologies (ATs), defined as “electrical or mechanical devices designed to help people recover movement”, demonstrate clinical benefits in upper limb stroke rehabilitation; however translation into clinical practice is poor. Uptake is dependent on a complex relationship between all stakeholders. Our aim was to understand patients’, carers’ (P&Cs) and healthcare professionals’ (HCPs) experience and views of upper limb rehabilitation and ATs, to identify barriers and opportunities critical to the effective translation of ATs into clinical practice. This work was conducted in the UK, which has a state funded healthcare system, but the findings have relevance to all healthcare systems.MethodsTwo structurally comparable questionnaires, one for P&Cs and one for HCPs, were designed, piloted and completed anonymously. Wide distribution of the questionnaires provided data from HCPs with experience of stroke rehabilitation and P&Cs who had experience of stroke. Questionnaires were designed based on themes identified from four focus groups held with HCPs and P&Cs and piloted with a sample of HCPs (N = 24) and P&Cs (N = 8). Eight of whom (four HCPs and four P&Cs) had been involved in the development.Results292 HCPs and 123 P&Cs questionnaires were analysed. 120 (41%) of HCP and 79 (64%) of P&C respondents had never used ATs. Most views were common to both groups, citing lack of information and access to ATs as the main reasons for not using them. Both HCPs (N = 53 [34%]) and P&C (N = 21 [47%]) cited Functional Electrical Stimulation (FES) as the most frequently used AT. Research evidence was rated by HCPs as the most important factor in the design of an ideal technology, yet ATs they used or prescribed were not supported by research evidence. P&Cs rated ease of set-up and comfort more highly.ConclusionKey barriers to translation of ATs into clinical practice are lack of knowledge, education, awareness and access. Perceptions about arm rehabilitation post-stroke are similar between HCPs and P&Cs. Based on our findings, improvements in AT design, pragmatic clinical evaluation, better knowledge and awareness and improvement in provision of services will contribute to better and cost-effective upper limb stroke rehabilitation.