Noninvasive Electromagnetic Neuromodulation of the Central and Peripheral Nervous System for Upper-Limb Motor Strength and Functionality in Individuals with Cervical Spinal Cord Injury: A Systematic Review and Meta-Analysis

(1) Background: Restoring arm and hand function is one of the priorities of people with cervical spinal cord injury (cSCI). Noninvasive electromagnetic neuromodulation is a current approach that aims to improve upper-limb function in individuals with SCI. The aim of this study is to review updated information on the different applications of noninvasive electromagnetic neuromodulation techniques that focus on restoring upper-limb functionality and motor function in people with cSCI. (2) Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were used to structure the search protocol. A systematic review of the literature was performed in three databases: the Cochrane Library, PubMed, and Physiotherapy Evidence Database (PEDro). (3) Results: Twenty-five studies were included: four were on transcranial magnetic stimulation (TMS), four on transcranial direct current stimulation (tDCS), two on transcutaneous spinal cord stimulation (tSCS), ten on functional electrical stimulation (FES), four on transcutaneous electrical nerve stimulation (TENS), and one on neuromuscular stimulation (NMS). The meta-analysis could not be completed due to a lack of common motor or functional evaluations. Finally, we realized a narrative review of the results, which reported that noninvasive electromagnetic neuromodulation combined with rehabilitation at the cerebral or spinal cord level significantly improved upper-limb functionality and motor function in cSCI subjects. Results were significant compared with the control group when tSCS, FES, TENS, and NMS was applied. (4) Conclusions: To perform a meta-analysis and contribute to more evidence, randomized controlled trials with standardized outcome measures for the upper extremities in cSCI are needed, even though significant improvement was reported in each non-invasive electromagnetic neuromodulation study.

Essential training variables of arm-hand training in people with cervical spinal cord injury: a systematic review

OBJECTIVE

To identify and evaluate 3 training variables of motor training programmes involving people with a cervical spinal cord injury: i.e. motor training strategies, therapy dosage, and persons' motivation for arm-hand functioning in subacute and chronic phases.

METHODS

PubMed, Cochrane, CINAHL, EMBASE, and DARE databases were searched for active arm-hand motor training programmes. Two independent reviewers assessed methodological quality. Pre-post effect sizes were calculated using Hedge's g, and mean effect sizes were calculated to compare outcomes on the International Classification of Functioning, Disability, and Health levels of function and activity.

RESULTS

Twelve training programmes integrated mainly skill training alone or combined with strength and/or endurance training. Task-oriented training components included: multiple movement planes, functional movements, clear functional goals, and bimanual practice. Training duration of 8 weeks was common. Quantitative analyses of 8 training programmes showed an overall small effect (0.34) on function level and an overall moderate effect (0.55) on activity level. In depth-analysis of activity level showed moderate effects of skill training only (0.55) or combined with strength and endurance training (0.53). Moderate effects (0.53-0.60) were found for integrating functional movements, clear functional goals, real-life object manipulation, multiple movement planes, total skill practice, context-specific environment, exercise variety, and bimanual practice. Training of minimum 8 weeks showed a moderate effect (0.60-0.69).

CONCLUSION

Based on limited studies, arm-hand functioning aiming to improve activity level can be improved using skill training with at least 8 task-oriented training components, additional strength and endurance training, with a minimum training duration of 8 weeks.

Superimposing neuromuscular electrical stimulation onto voluntary contractions to improve muscle strength and mass: a systematic review

Training and rehabilitation programs involving neuromuscular electrical stimulation superimposed onto voluntary contractions (NMES+) have gained popularity in the last decades. Yet, there is no clear consensus on the effectiveness of such intervention. The aim of this review was to evaluate the effect of chronic exposure to NMES+ on muscle strength and mass compared to conventional volitional training or passive electrical stimulation alone. Two authors conducted an electronic search to identify randomized controlled trials that investigated the effect of NMES+ training, involved healthy participants or orthopaedic patients, detailed a well-defined NMES training protocol, and provided outcomes related to skeletal-muscle strength and/or mass. The authors extracted data on participants, intervention characteristics, muscle-related outcomes, and assessed the methodological quality of the studies.A total of twenty-four studies were included in the review. The majority of these reported an increase in muscle strength following training with NMES+ compared to an equivalent voluntary training or passive NMES training. The highest improvements were found when NMES was superimposed on sub-maximal exercises involving both concentric and eccentric contractions. Only two studies reported an increase in muscle mass after NMES+ intervention, while no significant improvements were found in two other studies.This review indicated that chronic exposure to NMES+ determines muscle strength improvements greater or equal compared to volitional training alone. However, differences in the methodological characteristics of the stimulation and the type of exercise associated with NMES+, revealed significant discrepancies in the results. A deeper understanding of the neurophysiological adaptations to NMES+ is crucial to fully explain the muscle-related enhancement resulting from such intervention.

Physiotherapy interventions for increasing muscle strength in people with spinal cord injuries: a systematic review

STUDY DESIGN

A systematic review.

OBJECTIVE

The aim of this review was to determine the effectiveness of physiotherapy (PT) interventions for increasing voluntary muscle strength in people with spinal cord injuries (SCI).

METHODS

We included randomised controlled trials of PT interventions for people with SCI. We were interested in two comparisons: PT interventions compared with sham or no intervention, and PT interventions compared to each other. The outcome of interest was voluntary strength of muscles directly affected by SCI. All included studies were rated according to the Cochrane Risk of Bias Tool and results of similar trials were pooled using meta-analyses where possible.

RESULTS

Twenty-six trials met the inclusion criteria and provided useable data. A statistically significant between-group difference was found in four comparisons, namely, resistance training versus no intervention (standardised mean difference (SMD) = 0.64; 95% CI, 0.22-1.07; p = 0.003); resistance training combined with electrical stimulation versus no intervention (mean difference (MD) = 14 Nm; 95% CI, 1-27; p = 0.03); a package of PT interventions versus no intervention (MD = 4.8/50 points on the Lower Extremity Motor Score (LEMS); 95% CI 1.9-7.7; p = 0.01); and robotic gait training versus overground gait training (MD = 3.1/50 points on the LEMS; 95% CI, 1.3-5.0; p = 0.0008).

CONCLUSION

There is evidence that a small number of PT interventions increase voluntary strength in muscles directly affected by SCI.

Reliability of Wearable-Sensor-Derived Measures of Physical Activity in Wheelchair-Dependent Spinal Cord Injured Patients

Physical activity (PA) has been shown to have a positive influence on functional recovery in patients after a spinal cord injury (SCI). Hence, it can act as a confounder in clinical intervention studies. Wearable sensors are used to quantify PA in various neurological conditions. However, there is a lack of knowledge about the inter-day reliability of PA measures. The objective of this study was to investigate the single-day reliability of various PA measures in patients with a SCI and to propose recommendations on how many days of PA measurements are required to obtain reliable results. For this, PA of 63 wheelchair-dependent patients with a SCI were measured using wearable sensors. Patients of all age ranges (49.3 ± 16.6 years) and levels of injury (from C1 to L2, ASIA A-D) were included for this study and assessed at three to four different time periods during inpatient rehabilitation (2 weeks, 1 month, 3 months, and if applicable 6 months after injury) and after in-patient rehabilitation in their home-environment (at least 6 months after injury). The metrics of interest were total activity counts, PA intensity levels, metrics of wheeling quantity and metrics of movement quality. Activity counts showed consistently high single-day reliabilities, while measures of PA intensity levels considerably varied depending on the rehabilitation progress. Single-day reliabilities of metrics of movement quantity decreased with rehabilitation progress, while metrics of movement quality increased. To achieve a mean reliability of 0.8, we found that three continuous recording days are required for out-patients, and 2 days for in-patients. Furthermore, the results show similar weekday and weekend wheeling activity for in- and out-patients. To our knowledge, this is the first study to investigate the reliability of an extended set of sensor-based measures of PA in both acute and chronic wheelchair-dependent SCI patients. The results provide recommendations for sensor-based assessments of PA in clinical SCI studies.

Does Neuromuscular Electrical Stimulation Therapy Increase Voluntary Muscle Strength After Spinal Cord Injury? A Systematic Review

Background: Physical therapists frequently use neuromuscular electrical stimulation (NMES) therapy in an effort to increase the voluntary strength of partially paralyzed muscles in people with spinal cord injury (SCI), but it is not clear whether this treatment is effective. Objective: To determine the effectiveness of NMES for increasing voluntary strength in the partially paralyzed muscles of people with SCI. Methods: A systematic review of scientific literature was conducted in MEDLINE, CINAHL, PEDro, ScienceDirect, and Embase. Inclusion criteria were randomized controlled trials and controlled trials that compared NMES aimed at increasing strength in partially paralyzed muscles versus placebo/nothing or versus a nonstrengthening intervention or versus any other type of strengthening intervention in adults with SCI. Results: Five studies were included. Two studies found an increase in strength measured by peak force and manual muscle force test after an NMES protocol. One study found a between-group difference in favor of the NMES associated with progressive resistance training, and the other study showed an increase in the number of muscles improved by at least 1 degree of strength after NMES in combination with a cycle ergometer. The other 3 studies made several comparisons and found no differences between groups that received NMES and the controls. Conclusions: There is some suggestion that NMES increases voluntary strength in partially paralyzed muscle following SCI. However, there is no strong evidence to affirm the superiority of NMES over other treatment strategies used to gain strength in partially paralyzed muscles after SCI. These findings need replicating in large high-quality randomized controlled trials.

Long-term effects of an intensive interventional training program based on activities for individuals with spinal cord injury: a pilot study

OBJECTIVES

To investigate the long-term effects of a rehabilitation program using activity-based therapies in daily activities and the participation of individuals with spinal cord injury (SCI).

METHOD

A descriptive study of case reports assessing the performance of daily activities and quality of life as a dependent variable, using the Functional Independence Measure (FIM) and the Short-Form Health Survey (SF-36), respectively. Seven individuals were included in the intervention composed of a multimodal intensive therapies program based on activities (activity-based therapy, ABT) conducted for 18 months.

RESULTS

It was possible to descriptively observe that the individual with the shortest time of injury and previous training obtained the largest variation in the FIM score. But no statistically significant difference was found in the assessments.

CONCLUSION

For trained individuals with chronic SCIs, classified "A" according to the American Spinal Injury Association (ASIA), an ABT program did not significantly affect the scores of the scales used to assess quality of life (SF-36) and functional independence (FIM).

How well do randomised controlled trials of physical interventions for people with spinal cord injury adhere to the CONSORT guidelines? An analysis of trials published over a 10-year period

STUDY DESIGN

Cross-sectional descriptive study of randomised controlled trials involving physical interventions for people with spinal cord injury (SCI) published between 2003 and 2013.

OBJECTIVES

To determine how well randomised controlled trials of physical interventions for people with SCI adhere to the CONSORT (Consolidated Standards of Reporting Trials) guidelines.

SETTING

University of Sydney, Sydney, NSW, Australia.

METHODS

A search was conducted for randomised controlled trials designed to determine the effectiveness of physical interventions for people with SCI published between 2003 and 2013. The CONSORT checklist for the reporting of randomised controlled trials was used to determine how well each trial adhered to the guidelines. Two independent reviewers rated each trial on each of the 37 items on the CONSORT checklist using the following criteria: 'fully reported', 'partially reported', 'not reported', 'not relevant' or 'not reported but unable to determine if relevant/done'.

RESULTS

Fifty-three trials were retrieved. None of the trials 'fully reported' all items of the CONSORT guidelines. The median (IQR) number of items that was 'fully reported' was 11/37 (7-20). The median (IQR) number of items that was either 'fully reported' or 'not relevant' or 'not reported but unable to determine if relevant' was 20/37 items (17-27).

CONCLUSION

The reporting of randomised controlled trials in SCI is only partially adhering to the CONSORT guidelines. Journals can help lift standards by encouraging authors of randomised controlled trials to adhere to the CONSORT guidelines.

Effects of training on upper limb function after cervical spinal cord injury: a systematic review

Objective:

To summarize the evidence for the effectiveness of exercise training in promoting recovery of upper extremity function after cervical spinal cord injury.

Data sources:

Medline, Cochrane, CINAHL, EMBASE and PEDro were used to search the literature.

Review methods:

Two reviewers independently selected and summarized the included studies. Methodological quality of the selected articles was scored using the Downs and Black checklist.

Results:

A total of 16 studies were included, representing a total of 426 participants. Overall, the internal validity and reporting of the studies was fair to good, while power and external validity were poor. Interventions included exercise therapy, electrical stimulation, functional electrical stimulation, robotic training and repetitive transcranial magnetic stimulation. Most of the studies reported improvements in muscle strength, arm and hand function, activity of daily living or quality of life after intervention.

Conclusions:

Training including exercise therapy, electrical stimulation, functional electrical stimulation of the upper limb following cervical spinal cord injury leads to improvements in muscle strength, upper limb function and activity of daily living or quality of life. Further research is needed into the effects of repetitive transcranial magnetic stimulation and robotic training on upper limb function.

Neural adaptations to electrical stimulation strength training

This review provides evidence for the hypothesis that electrostimulation strength training (EST) increases the force of a maximal voluntary contraction (MVC) through neural adaptations in healthy skeletal muscle. Although electrical stimulation and voluntary effort activate muscle differently, there is substantial evidence to suggest that EST modifies the excitability of specific neural paths and such adaptations contribute to the increases in MVC force. Similar to strength training with voluntary contractions, EST increases MVC force after only a few sessions with some changes in muscle biochemistry but without overt muscle hypertrophy. There is some mixed evidence for spinal neural adaptations in the form of an increase in the amplitude of the interpolated twitch and in the amplitude of the volitional wave, with less evidence for changes in spinal excitability. Cross-sectional and exercise studies also suggest that the barrage of sensory and nociceptive inputs acts at the cortical level and can modify the motor cortical output and interhemispheric paths. The data suggest that neural adaptations mediate initial increases in MVC force after short-term EST.