Optimal electrode position for abdominal functional electrical stimulation

Abdominal functional electrical stimulation (abdominal FES) improves respiratory function. Despite this, clinical use remains low, possibly due to lack of agreement on the optimal electrode position. This study aimed to ascertain the optimal electrode position for abdominal FES, assessed by expiratory twitch pressure. Ten able-bodied participants received abdominal FES using electrodes placed: 1) on the posterolateral abdominal wall and at the motor points of 2) the external oblique muscles plus rectus abdominis muscles, and 3) the external obliques alone. Gastric (Pga) and esophageal (Pes) twitch pressures were measured using a gastroesophageal catheter. Single-stimulation pulses were applied at functional residual capacity during step increments in stimulation current to maximal tolerance or until Pga plateaued. Stimulation applied on the posterolateral abdominal wall led to a 71% and 53% increase in Pga and Pes, respectively.compared with stimulation of the external oblique and rectus abdominis muscles (P < 0.001) and a 95% and 56% increase in Pga and Pes, respectively.compared with stimulation of the external oblique muscles alone (P < 0.001). Stimulation of both the external oblique and rectus abdominis muscles led to an 18.3% decrease in Pg.compared with stimulation of only the external oblique muscles (P = 0.040), with inclusion of the rectus abdominis having no effect on Pes (P = 0.809). Abdominal FES applied on the posterolateral abdominal wall generated the highest expiratory twitch pressures. As expiratory pressure is a good indicator of expiratory muscle strength and, thus, cough efficacy, we recommend this electrode position for all therapeutic applications of abdominal FES. NEW & NOTEWORTHY While abdominal functional electrical stimulation (abdominal FES) can improve respiratory function, clinical use remains low. This is at least partly due to lack of agreement on the optimal electrode position. Therefore, this study aimed to ascertain the optimal electrode position for abdominal FES. We show that electrodes placed on the posterolateral abdominal wall generated the highest expiratory twitch pressures. As such, we recommend this electrode position for all therapeutic applications of abdominal FES

Abdominal functional electrical stimulation to augment respiratory function in spinal cord injury

Background: Functional electrical stimulation (FES) is the application of electrical pulses to a nerve to achieve a functional muscle contraction. Surface electrical stimulation of the nerves that innervate the abdominal muscles, termed abdominal FES, can cause the abdominal muscles to contract, even when paralysed after spinal cord injury. As the abdominal muscles are the major expiratory muscles, and commonly partially or completely paralysed in tetraplegia, abdominal FES offers a promising method of improving respiratory function for this patient group. Objective: The aim of the article is to provide readers with a better understanding of how abdominal FES can be used to improve the health of the spinal cord–injured population. Methods: A narrative review of the abdominal FES literature was performed. Results: Abdominal FES can achieve an immediate effective cough in patients with tetraplegia, while the repeated application over 6 weeks of abdominal FES can improve unassisted respiratory function. Ventilator duration and tracheostomy cannulation time can also be reduced with repeated abdominal FES. Conclusion: Abdominal FES is a noninvasive method to achieve functional improvements in cough and respiratory function in acute and chronically injured people with tetraplegia. Potential practical outcomes of this include reduced ventilation duration, assisted tracheostomy decannulation, and a reduction in respiratory complications. All of these outcomes can contribute to reduced morbidity and mortality, improved quality of life, and significant potential cost savings for local health care providers

The frequency of bowel and bladder problems in multiple sclerosis and its relation to fatigue: A single centre experience

Background Bowel and bladder problems affect more than 50% of people with Multiple Sclerosis (MS). These problems have a large impact on quality of life and place a significant burden on health systems. Objectives This study aimed to ascertain the frequency of bladder and bowel problems in a select Australian MS cohort and to investigate the relationships between level of disability, bladder and bowel problems, and fatigue. Methods Questionnaires on the nature and severity of MS symptoms were distributed to clients attending an Australian MS centre. Log-binomial regression and multiple linear regression models were used to investigate relationships between disability, fatigue, and bladder and bowel problems. Results and conclusions Of 167 questionnaires distributed, 136 were completed. Bladder problems were reported by 87 (74.4%) respondents, whilst 66 (48.9%) experienced functional constipation and 43 (31.9%) faecal incontinence. This frequency in our select Australian MS population is similar to that reported globally. There was a significant correlation between level of disability and: bladder problems (p = 0.015), faecal incontinence (p = 0.001), fatigue (p<0.001) and constipation (p = 0.016, relative risk: 1.16). Further investigation into the causal relationships between various MS symptoms may be beneficial in the development of novel therapeutic strategies for people with MS

Inspiratory muscle reflex control after incomplete cervical spinal cord injury

In healthy individuals, loading inspiratory muscles by brief inspiratory occlusion produces a short-latency inhibitory reflex (IR) in the electromyographic (EMG) activity of scalene and diaphragm muscles. This IR may play a protective role to prevent aspiration and airway collapse during sleep. In people with motor and sensory complete cervical spinal cord injury (cSCI), who were able to breathe independently, this IR was predominantly absent. Here, we investigated the reflex response to brief airway occlusion in 16 participants with sensory incomplete cSCI [American spinal injury association impairment scale (AIS) score B or C]. Surface EMG was recorded from scalene muscles and the lateral chest wall (overlying diaphragm). The airway occlusion evoked a small change in mouth pressure resembling a physiological occlusion. The short-latency IR was present in 10 (63%) sensory incomplete cSCI participants; significantly higher than the IR incidence observed in complete cSCI participants in our previous study (14%; P = 0.003). When present, mean IR latency across all muscles was 58 ms (range 29-79 ms), and mean rectified EMG amplitude decreased to 37% preocclusion levels. Participants without an IR had untreated severe obstructive sleep apnea (OSA), in contrast to those with an IR, who had either had no, mild, or treated OSA (P = 0.002). Insufficient power did not allow statistical comparison between IR presence or absence and participant clinical characteristics. In conclusion, spared sensory connections or intersegmental connections may be necessary to generate the IR. Future studies to establish whether IR presence is related to respiratory morbidity in the tetraplegic population are required. NEW & NOTEWORTHY Individuals with incomplete cSCI were tested for the presence of a short latency reflex inhibition of inspiratory muscles, by brief airway occlusion. The reflex was 4.5 times more prevalent in this group compared with those with complete cSCI and is similar to the incidence in able-bodied people. Participants without this reflex all had untreated severe OSA, in contrast to those with an IR, who either had no, mild, or treated OSA. This work reveals novel differences in the reflex control of inspiratory muscles across the cSCI population

Abdominal functional electrical stimulation to improve respiratory function after spinal cord injury: a systematic review and meta-analysis

Objectives: Abdominal functional electrical stimulation (abdominal FES) is the application of a train of electrical pulses to the abdominal muscles, causing them to contract. Abdominal FES has been used as a neuroprosthesis to acutely augment respiratory function and as a rehabilitation tool to achieve a chronic increase in respiratory function after abdominal FES training, primarily focusing on patients with spinal cord injury (SCI). This study aimed to review the evidence surrounding the use of abdominal FES to improve respiratory function in both an acute and chronic manner after SCI. Settings: A systematic search was performed on PubMed, with studies included if they applied abdominal FES to improve respiratory function in patients with SCI. Methods: Fourteen studies met the inclusion criteria (10 acute and 4 chronic). Low participant numbers and heterogeneity across studies reduced the power of the meta-analysis. Despite this, abdominal FES was found to cause a significant acute improvement in cough peak flow, whereas forced exhaled volume in 1 s approached significance. A significant chronic increase in unassisted vital capacity, forced vital capacity and peak expiratory flow was found after abdominal FES training compared with baseline. Conclusions: This systematic review suggests that abdominal FES is an effective technique for improving respiratory function in both an acute and chronic manner after SCI. However, further randomised controlled trials, with larger participant numbers and standardised protocols, are needed to fully establish the clinical efficacy of this technique

Epidemiology of traumatic spinal cord injury in Galicia, Spain: trends over a 20-year period

[Abstract] Study design: Observational study with prospective and retrospective monitoring. Objective: To describe the epidemiological and demographic characteristics of traumatic spinal cord injury (TSCI), and to analyze its epidemiological changes. Setting: Unidad de Lesionados Medulares, Complejo Hospitalario Universitario A Coruña, in Galicia (Spain). Methods: The study included patients with TSCI who had been hospitalized between January 1995 and December 2014. Relevant data were extracted from the admissions registry and electronic health record. Results: A total of 1195 patients with TSCI were admitted over the specified period of time; 76.4% male and 23.6% female. Mean patient age at injury was 50.20 years. Causes of injury were falls (54.2%), traffic accidents (37%), sports/leisure-related accidents (3.5%) and other traumatic causes (5.3%). Mean patient age increased significantly over time (from 46.40 to 56.54 years), and the number of cases of TSCI related to traffic accidents decreased (from 44.5% to 23.7%), whereas those linked to falls increased (from 46.9% to 65.6%). The most commonly affected neurological level was the cervical level (54.9%), increasing in the case of levels C1–C4 over time, and the most frequent ASIA (American Spinal Injury Association) grade was A (44.3%). The crude annual incidence rate was 2.17/100 000 inhabitants, decreasing significantly over time at an annual percentage rate change of −1.4%. Conclusions: The incidence rate of TSCI tends to decline progressively. Mean patient age has increased over time and cervical levels C1–C4 are currently the most commonly affected ones. These epidemiological changes will eventually result in adjustments in the standard model of care for TSCI

Plant ecology meets animal cognition: impacts of animal memory on seed dispersal

We propose that an understanding of animal learning and memory is critical to predicting the impacts of animals on plant populations through processes such as seed dispersal, pollination and herbivory. Focussing on endozoochory, we review the evidence that animal memory plays a role in seed dispersal, and present a model which allows us to explore the fundamental consequences of memory for this process. We demonstrate that decision-making by animals based on their previous experiences has the potential to determine which plants are visited, which fruits are selected to be eaten from the plant and where seeds are subsequently deposited, as well as being an important determinant of animal survival. Collectively, these results suggest that the impact of animal learning and memory on seed dispersal is likely to be extremely important, although to date our understanding of these processes suffers from a conspicuous lack of empirical support. This is partly because of the difficulty of conducting appropriate experiments but is also the result of limited interaction between plant ecologists and those who work on animal cognition

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Abdominal Functional Electrical Stimulation to Assist Ventilator Weaning in Acute Tetraplegia: A Cohort Study.

BACKGROUND: Severe impairment of the major respiratory muscles resulting from tetraplegia reduces respiratory function, causing many people with tetraplegia to require mechanical ventilation during the acute stage of injury. Abdominal Functional Electrical Stimulation (AFES) can improve respiratory function in non-ventilated patients with sub-acute and chronic tetraplegia. The aim of this study was to investigate the clinical feasibility of using an AFES training program to improve respiratory function and assist ventilator weaning in acute tetraplegia. METHODS: AFES was applied for between 20 and 40 minutes per day, five times per week on four alternate weeks, with 10 acute ventilator dependent tetraplegic participants. Each participant was matched retrospectively with a ventilator dependent tetraplegic control, based on injury level, age and sex. Tidal Volume (VT) and Vital Capacity (VC) were measured weekly, with weaning progress compared to the controls. RESULTS: Compliance to training sessions was 96.7%. Stimulated VT was significantly greater than unstimulated VT. VT and VC increased throughout the study, with mean VC increasing significantly (VT: 6.2 mL/kg to 7.8 mL/kg VC: 12.6 mL/kg to 18.7 mL/kg). Intervention participants weaned from mechanical ventilation on average 11 (sd: ± 23) days faster than their matched controls. CONCLUSION: The results of this study indicate that AFES is a clinically feasible technique for acute ventilator dependent tetraplegic patients and that this intervention may improve respiratory function and enable faster weaning from mechanical ventilation. TRIAL REGISTRATION: ClinicalTrials.gov NCT02200393