Optimization of Protocols Using Neuromuscular Electrical Stimulation for Paralyzed Lower-Limb Muscles to Increase Energy Expenditure in People With Spinal Cord Injury.

OBJECTIVE: The aim of this study was to evaluate whether using surface neuromuscular electrical stimulation (NMES) for paralyzed lower-limb muscles results in an increase in energy expenditure and whether the number of activated muscles and duty cycle affect the potential increase. DESIGN: This was a cross-sectional study. RESULTS: Energy expenditure during all NMES protocols was significantly higher than the condition without NMES (1.2 ± 0.2 kcal/min), with the highest increase (+51%; +0.7 kcal/min, 95% confidence interval, 0.3-1.2) for the protocol with more muscles activated and the duty cycle with a shorter rest period. A significant decrease in muscle contraction size during NMES was found with a longer stimulation time, more muscles activated, or the duty cycle with a shorter rest period. CONCLUSION: Using NMES for paralyzed lower-limb muscles can significantly increase energy expenditure compared with sitting without NMES, with the highest increase for the protocol with more muscles activated and the duty cycle with a shorter rest period. Muscle fatigue occurred significantly with the more intense NMES protocols, which might cause a lower energy expenditure in a longer protocol. Future studies should further optimize the NMES parameters and investigate the long-term effects of NMES on weight management in people with SCI.

Twelve-Week Daily Gluteal and Hamstring Electrical Stimulation Improves Vascular Structure and Function, Limb Volume, and Sitting Pressure in Spinal Cord Injury: A Pilot Feasibility Study.

OBJECTIVE: We examined the long-term effects of low-intensity electrical stimulation on (micro)vasculature and sitting pressure of a home-based, wearable electrical stimulation device in a pilot feasibility study. DESIGN: In a cohort observation before-after trial, nine middle-aged male (n = 8) and female (n = 1) individuals (48 ± 15 yrs) with American Spinal Injury Association A-C classified chronic (1-24 yrs) spinal cord injury underwent 12 wks of self-administered daily, low-intensity gluteal and hamstring electrical stimulation (50 Hz, 6 hrs [30-min electrical stimulation, 15-min rest]). Common femoral artery diameter and blood blow were determined with ultrasound, skin vascular function during local heating was assessed using Laser-Doppler flowmetry, thigh volume was estimated using leg circumferences and skinfolds, and interface sitting pressure was measured using pressure mapping. RESULTS: Resting common femoral artery diameter increased (0.73 ± 0.20 to 0.79 ± 0.22 cm, P < 0.001) and baseline common femoral artery blood flow increased (0.28 ± 0.12 to 0.40 ± 0.15 l/min, P < 0.002). Gluteal cutaneous vascular conductance showed a time*temperature interaction (P = 0.01) with higher conductance at 42°C after 12 wks. Ischial peak pressure decreased (P = 0.003) by 32 ± 23 mm Hg and pressure gradient decreased (23 ± 7 to 16 ± 6 mm Hg, P = 0.007). Thigh volume increased (+19%, P = 0.01). CONCLUSIONS: Twelve-week daily home-based gluteal and hamstring electrical stimulation is feasible and effective to improve (micro)vasculature and sitting pressure, and electrical stimulation may have clinical implications for ameliorating pressure ulcers and (micro)vascular complications in spinal cord injury.

Feasibility of overnight electrical stimulation-induced muscle activation in people with a spinal cord injury. A Pilot study.

Study Design: We investigated whether overnight ES is a feasible method to activate gluteal, quadriceps, and hamstrings muscles in a two-week experiment. Electrical stimulation (ES) induced muscle contractions have proven positive effects on risk factors for developing pressure ulcers in people with a spinal cord injury (SCI). Therefore prolonged overnight ES-induced muscle activation is interesting, but has never been studied. Objective: To study feasibility of ES-induced leg muscle activation. In eight participants with motor complete SCI gluteal, hamstrings and quadriceps muscles were activated with a 2-weeks overnight stimulation protocol, 8 h per night, using specially developed ES-shorts. Setting: The Netherlands. Methods: Muscle fatigue was determined with a muscle contraction sensor. Questionnaires on sleep quality (SQ) and the ES-shorts usability were taken. Results: After 8 h of activation muscles still contracted, although fatigue occurred, and mean contraction size was lower at the end of a cycle (p = 0.03). SQ (0-100) after intervention was 75, and 66 after 4 weeks without overnight ES (p = 0.04) indicating ES improves sleep quality. The usability of the ES-shorts was good. Conclusions: This study shows that overnight ES-induced muscle activation using ES-shorts in SCI is a new, feasible method that does not interfere with sleep. The nightly use of the ES-shorts might be considered as an important part of the daily routine in SCI.

Femoral Artery Blood Flow and Microcirculatory Perfusion During Acute, Low-Level Functional Electrical Stimulation in Spinal Cord Injury.

OBJECTIVE: Functional electrical stimulation (FES) may help to reduce the risk of developing macrovascular and microvascular complications in people with spinal cord injury. Low-intensity FES has significant clinical potential because this can be applied continuously throughout the day. This study examines the acute effects of low-intensity FES using wearable clothing garment on vascular blood flow and oxygen consumption in people with spinal cord injury. DESIGN: This was a cross-sectional observation study. METHODS: Eight participants with a motor complete spinal cord injury received four 3-min unilateral FES to the gluteal and hamstring muscles. Skin and deep femoral artery blood flow and oxygen consumption were measured at baseline and during each bout of stimulation. RESULTS: Femoral artery blood flow increased by 18.1% with the application of FES (P = 0.02). Moreover, femoral artery blood flow increased further during each subsequent block of FES (P = 0.004). Skin perfusion did not change during an individual block of stimulation (P = 0.66). Skin perfusion progressively increased with each subsequent bout (P < 0.001). There was no change in femoral or skin perfusion across time in the nonstimulated leg (all P > 0.05). CONCLUSION: Low-intensity FES acutely increased blood flow during stimulation, with a progressive increase across subsequent FES bouts. These observations suggest that continuous, low-intensity FES may represent a practical and effective strategy to improve perfusion and reduce the risk of vascular complications.

Effects of Electrical Stimulation on Risk Factors for Developing Pressure Ulcers in People with a Spinal Cord Injury: A Focused Review of Literature.

Pressure ulcers (PUs) are a common and serious problem for wheelchair users, such as individuals with a spinal cord injury (SCI), resulting in great discomfort, loss of quality of life, and significant medical care costs. Therefore, it is of utmost importance to prevent PUs. In this literature overview, the effects of electrical stimulation (ES) on the risk factors for developing PUs in people with an SCI are examined and synthesized from January 1980 to January 2015. Thirty-four relevant studies of PU prevention in SCI were identified. Four were randomized clinical trials, 24 were case series, 6 had other designs. Three types of ES modalities were identified. The methodological quality varied from poor to fairly strong, with a large variety in used ES parameters. Twenty-three studies were identified describing short-term effects of ES on interface pressure, oxygenation, and/or blood flow, and 24 studies described the long-term effects of ES on muscle volume, muscle strength, and histology. Whereas there is a lack of controlled studies on the effects of ES on PU incidence, which disallows definite conclusions, there is moderate evidence to suggest that ES-induced muscle activation has a positive influence on several risk factors for developing PUs in people with an SCI.

Prolonged electrical stimulation-induced gluteal and hamstring muscle activation and sitting pressure in spinal cord injury: effect of duty cycle.

Pressure ulcers (PUs) are highly prevalent in people with spinal cord injury (SCI). Electrical stimulation (ES) activates muscles and might reduce risk factors. Our objectives were to study and compare the effects of two duty cycles during 3 h of ES-induced gluteal and hamstring activation on interface pressure distribution in sitting individuals with SCI and study the usability of a newly developed electrode garment (ES shorts). Ten individuals with SCI participated in this study, in which two ES protocols with different duty cycles (1:1 s vs 1:4 s on-off) were applied in counterbalanced order using a custom-made garment with built-in electrodes. Outcome variables included interface pressure of the ischial tuberosities (ITs) and pressure gradient. A questionnaire was used to determine usability of the ES shorts. In both protocols, ES caused a significant decrease in average IT pressure compared with rest (no ES); on average, 35% for protocol 1:4 and 13% for protocol 1:1. The ES on-off duty cycle of protocol 1:4 showed less muscle fatigue. In general, participants scored the usability of the ES shorts as satisfactory. In this study, the application of ES resulted in a significant decrease in IT pressure. The ES on-off duty cycle of 1:4 s is recommended because of the less fatiguing effect. ES of the hamstrings and gluteal muscles might be a promising method in preventing PUs, but further study is needed.

The influence of time and adaptation on health state valuations in patients with spinal cord injury.

OBJECTIVES: One of the explanations for the difference between health state utilities elicited from patients and the public--often provided but seldom studied--is adaptation. The influence of adaptation on utilities was investigated in patients with spinal cord injury. METHODS: Interviews were held at 3 time points (T1, after admission to the rehabilitation center; T2, during active rehabilitation; T3, at least half a year after discharge). At T1, 60 patients were interviewed; 10 patients withdrew at T2 and T3. At all time points, patients were asked to value their own health and a health state description of rheumatoid arthritis on a time trade-off and a visual analogue scale. The Barthel Index, a measure of independence from help in activities of daily living, and the adjustment ladder were filled out. Main analyses were performed using mixed linear models taking the time-dependent covariates (Barthel Index and adjustment ladder) into account. RESULTS: Time trade-off valuations for patients' own health changed over time, even after correction for gain in independence from help in activities of daily living, F(2, 59) = 8.86, P < 0.001. This change was related to overall adaptation. Both a main effect for adaptation, F(87, 1) = 10.05; P = 0.002, and an interaction effect between adaptation and time, F(41, 1)= 4.10, P = 0.024, were seen for time trade-off valuations. Valuations given for one's own health on the visual analogue scale did not significantly change over time, nor did the valuations for the hypothetical health state. CONCLUSION: Patients' health state valuations change over time, over and above the change expected by the rehabilitation process, and this change is partly explained by adaptation. Experience with a chronic illness did not lead to change in valuations of hypothetical health states.