Posts Tagged Electric stimulation
[Abstract] The effect of peripheral nerve electrical stimulation on corticomotor excitability and motor function of the paretic hand in stroke
Electrical stimulation to the stroke-affected paretic upper limb (UL) has been a treatment to promote its motor recovery. Despite its efficacy in promoting muscle strength and enhancing motor training, the underlying neurophysiological mechanism for such motor improvement has not been clear. It is crucial to delineate the corticomotor plasticity effects of electrical stimulation when it is applied as a single entity and as an adjunct to other forms of therapies, since the knowledge would support formulation of effective treatment for the paretic UL in stroke rehabilitation.
This dissertation incorporated 4 studies to examine the corticomotor excitability modulation and motor function effects of electrical stimulation on the paretic UL due to stroke. Study 1 reviewed randomized controlled trials published before 2012 to scrutinize the efficacy of electrical stimulation on motor function improvement as well as corticomotor excitability for muscles in the paretic hand. Results of the meta-analysis showed that electrical stimulation could improve UL motor impairment but not its ability in functional task performance measured with the Action Research Arm Test. The corticomotor excitability changes associated with electrical stimulation could not be concluded because of diverse outcomes reported in only 3 studies. Study 2 was a randomized cross-over sham-controlled experiment (n = 32) set to determine a single session of 1-hour electrical stimulation delivered to the ulnar and radial nerves (PNS) of the paretic UL at an intensity of 2 to 3 sensory thresholds in modulating the corticomotor excitability in both brain hemispheres. The results confirmed that PNS could increase corticomotor excitability in terms of the recruitment curve (RC) slope and peak amplitude of motor-evoked potentials (pMEP) for the corticospinal projections to the contralateral first dorsal interosseous hand muscle (FDI) measured in both hemispheres. The PNS also enhanced better hand pincer dexterity scored by the Purdue pegboard test than the sham stimulation (PNSsham). Then Study 3 was conducted to examine if PNS could condition the corticomotor pathways for another treatment targeting motor improvement in the paretic UL. This pilot randomized cross-over study involved 20 subjects to receive 1-hour PNS paired with observation of movement demonstration in videos (termed action observation, AO) that was introduced during the last 30 minutes of PNS. PNS+AO improved the Purdue dexterity score of the paretic hand, but the change in corticomotor excitability for the contralateral FDI in the lesioned hemisphere was not significant. The control intervention PNSsham+AO did not change any of the outcome measurements. Study 4 further tested the hypothesis that PNS and/or jointly with AO might effectively condition motor training of the paretic UL in enhancing corticomotor plastic changes and hand dexterity. In this randomized sham-controlled cross-over study, 20 subjects in chronic stage of stroke were exposed to 3 separate sessions of different interventions composed of 1-hour PNS or PNSsham paired with 30 minutes of AO or sham AO (AOsham), all followed by 30-minute training of index finger abduction. The results revealed that PNS+AO+Training led to significantly increased corticomotor excitability in terms of RC slope and pMEP amplitude localized in the lesioned hemisphere but that of the intact hemisphere was not altered. This neuroplastic modulation was accompanied by enhanced hand dexterity at 24 hours post-intervention better than the control with PNSsham+AOsham+Training. On the other hand, PNS+AOsham+Training did not modulate corticomotor excitability functions but hand dexterity was increased immediately after the intervention better than after PNSsham+AOsham+Training. Training after PNSsham+AOsham conditioning was not effective on the outcome measurements.
Results of the series of studies supported that (1) one-hour PNS could increase the excitability of corticomotor pathways for the contralateral hand muscle in both the lesioned and intact hemispheres similarly; (2) one-hour PNS alone, or applied as a conditioning treatment in the presence of AO or AOsham prior to movement training in the paretic hand could lead to better hand dexterity than training after sham controls; (3) Up-regulation of corticomotor excitability specifically confined to the stroke-lesioned hemisphere was evident after a session of PNS paired with AO and Training.
To conclude, one session of PNS or PNS-associated interventions for the paretic UL could effectively improve dexterity of the paretic hand in people with chronic stroke. PNS might have primed the corticomotor pathways for AO and motor training to result in corticomotor excitability enhancement specifically confined to the stroke-lesioned hemisphere.
Background and Purpose—Neuromuscular electric stimulation (NMES) has been used to reduce spasticity and improve range of motion in patients with stroke. However, contradictory results have been reported by clinical trials. A systematic review of randomized clinical trials was conducted to assess the effect of treatment with NMES with or without association to another therapy on spastic muscles after stroke compared with placebo or another intervention.
Methods—We searched the following electronic databases (from inception to February 2015): Medline (PubMed), EMBASE, Cochrane Central Register of Controlled Trials and Physiotherapy Evidence Database (PEDro). Two independent reviewers assessed the eligibility of studies based on predefined inclusion criteria (application of electric stimulation on the lower or upper extremities, regardless of NMES dosage, and comparison with a control group which was not exposed to electric stimulation), excluding studies with ❤ days of intervention. The primary outcome extracted was spasticity, assessed by the Modified Ashworth Scale, and the secondary outcome extracted was range of motion, assessed by Goniometer.
Results—Of the total of 5066 titles, 29 randomized clinical trials were included with 940 subjects. NMES provided reductions in spasticity (−0.30 [95% confidence interval, −0.58 to −0.03], n=14 randomized clinical trials) and increase in range of motion when compared with control group (2.87 [95% confidence interval, 1.18–4.56], n=13 randomized clinical trials) after stroke.
Conclusions—NMES combined with other intervention modalities can be considered as a treatment option that provides improvements in spasticity and range of motion in patients after stroke.
[Supplement] It Takes Two: Noninvasive Brain Stimulation Combined With Neurorehabilitation- Full Text
The goal of postacute neurorehabilitation is to maximize patient function, ideally by using surviving brain and central nervous system tissue when possible. However, the structures incorporated into neurorehabilitative approaches often differ from this target, which may explain why the efficacy of conventional clinical treatments targeting neurologic impairment varies widely.
Noninvasive brain stimulation (eg, transcranial magnetic stimulation [TMS], transcranial direct current stimulation [tDCS]) offers the possibility of directly targeting brain structures to facilitate or inhibit their activity to steer neural plasticity in recovery and measure neuronal output and interactions for evaluating progress. The latest advances as stereotactic navigation and electric field modeling are enabling more precise targeting of patient’s residual structures in diagnosis and therapy.
Given its promise, this supplement illustrates the wide-ranging significance of TMS and tDCS in neurorehabilitation, including in stroke, pediatrics, traumatic brain injury, focal hand dystonia, neuropathic pain, and spinal cord injury. TMS and tDCS are still not widely used and remain poorly understood in neurorehabilitation. Therefore, the present supplement includes articles that highlight ready clinical application of these technologies, including their comparative diagnostic capabilities relative to neuroimaging, their therapeutic benefit, their optimal delivery, the stratification of likely responders, and the variable benefits associated with their clinical use because of interactions between pathophysiology and the innate reorganization of the patient’s brain. Overall, the supplement concludes that whether provided in isolation or in combination, noninvasive brain stimulation and neurorehabilitation are synergistic in the potential to transform clinical practice.
The incidence of many neurologic diseases is rising partly because of an increasingly aged population and improved delivery and timing of acute care for neurologic disorders. As a result, more survivors are emerging from acute care, with most exhibiting life-altering impairments that require neurorehabilitation. One prominent example of this trend is stroke; taking into account both the years of potential life lost from premature death and long-term disability, stroke is also one of the most costly diseases, with 36% of this growing population exhibiting a discernable disability 5 years poststroke,1 and almost half of survivors remaining dependent on others 6 years poststroke because of the severity of their disability.2
The focus of medical teams during hyperacute and acute neurologic care is usually 3-fold: ensure survival/reduce mortality; manage and prevent medical complications; and when possible, salvage existing central nervous system tissue (eg, through the use of thrombolytics in stroke).3 In contrast, the goal of postacute neurorehabilitation is to maximize patient function, ideally by using surviving brain and central nervous system tissue when possible. However, despite their widely appreciated importance, the efficacy of conventional clinical treatments targeting specific neurologic impairments and sequelae vary widely. Again in the case of stroke, conventional rehabilitative strategies targeting upper extremity hemiparesis in adults offer negligible or no efficacy.4, 5
Recently developed neurorehabilitative strategies offer slightly more promise but remain limited because of the considerable time and resources that they require to administer. Perhaps the most notable example is constraint-induced movement therapy (CIMT), which has been applied to the affected upper extremity after stroke and other neurologic disorders (eg, multiple sclerosis, aphasia, traumatic brain injury [TBI]). One of the hallmarks of CIMT is long-duration training using an affected body part (eg, paretic upper extremity) or capacity (eg, speaking) that lasts up to 6 hours per day and is administered over multiple days (usually 10 consecutive weekdays). Although results have been promising,6 several studies7, 8 have found that most patients with stroke do not wish to participate in CIMT because of these long-duration treatment parameters, have reported high attrition rates,9 have reported poor compliance with the CIMT restrictive device wear,10, 11 and have reported on patient inability to participate in the entire 6-hour regimen as a result of fatigue.12 As a result of the required time, financial resources, and human resources, CIMT has not realized widespread clinical application.13, 14
Other new neurorehabilitative approaches being taught by training programs and/or adopted by clinics worldwide (eg, partial weight-supported treadmill training, certain automated and splinting approaches) offer negligible efficacy when compared with more conventional strategies15, 16, 17 and/or only work on patients displaying a particular level of impairment. As a result, there remains a gap centering on the need for techniques that extend the efficacy, duration of treatment effect, and/or number of patients who may benefit from promising neurorehabilitative therapies. Noninvasive brain stimulation offers the ability to meet all of these needs and offers efficacy as a stand-alone treatment approach for many neurologic impairments.
[ARTICLE] Invited Commentary on Comparison of Robotics, FES, and Motor Learning Methods for Treatment of Persistent Upper Extremity Dysfunction after Stroke
In this issue of Archives of Physical Medicine and Rehabilitation, Jessica McCabe and colleagues report findings from their methodologically sound dose-matched clinical trial in 39 patients beyond 6 months post stroke. In this phase II trial, the effects of 60 treatment sessions, each involving 3.5 hours of intensive practice plus either 1.5 hours of functional electrical stimulation (FES) or a shoulder-arm robotic therapy, were compared with 5 hours of intensive daily practice alone. Although no significant between-group differences were found on the primary outcome measure of Arm Motor Ability Test (AMAT) and the secondary outcome measure of Fugl Meyer Arm (FMA) motor score, 10 to 15% within-group therapeutic gains were observed regarding AMAT and FMA. These gains are clinically meaningful for patients with stroke. However, the underlying mechanisms that drive these improvements remain poorly understood. The approximately 1000 dollar cost reduction per patient calculated for the use of motor learning (ML) methods alone or combined with FES, compared to the combination of ML and shoulder arm-robotics, further emphasizes the need for cost considerations when making clinical decisions about selecting the most appropriate therapy for the upper paretic limb in clients suffering from chronic stroke.
via Invited Commentary on Comparison of Robotics, FES, and Motor Learning Methods for Treatment of Persistent Upper Extremity Dysfunction after Stroke: a Randomized Controlled Trial – Archives of Physical Medicine and Rehabilitation.
[ARTICLE] Comparison of Robotics, FES, and Motor Learning Methods for Treatment of Persistent Upper Extremity Dysfunction after Stroke: a Randomized Controlled Trial
Objective: To compare response to upper limb treatment using robotics (ROB) + motor learning (ML) vs. functional electrical stimulation (FES) + ML vs. ML alone, according to a measure of complex functional everyday tasks for chronic, severely impaired stroke survivors.
Design: single-blind, randomized trial.
Setting: Clinical research lab, Medical Center.
Participants: 39 enrolled subjects, >1 year post single stroke (attrition rate=10%; 35 completed the study). No adverse effects.
Interventions: All groups received treatment 5 days/week, 5hrs/day (60 sessions), with unique treatment as follows: ML alone (n=11), 5hrs/day partial and whole task practice of complex functional tasks; ROB+ML (n=12), 3.5hrs/day ML and 1.5hrs/day shoulder/elbow robotics; FES+ML (n=12), 3.5hrs/day ML and 1.5hrs/day FES wrist/hand coordination training.
Main Outcome Measures: Primary measure: Arm Motor Ability Test (AMAT), 13 complex functional tasks; secondary measure: upper limb Fugl-Meyer coordination (FM).
Results: No significant difference found in treatment response across groups (AMAT (p≥.584) and FM (p≥.590)). All three treatment groups demonstrated clinically and statistically significant improvement in response to treatment (AMAT and FM, p≤.009). A group treatment paradigm of 1:3 (therapist:patient) ratio proved feasible for provision of the intensive treatment.
Conclusions: Severely impaired stroke survivors with persistent (>1yr) upper extremity dysfunction can make clinically and statistically significant gains in coordination and functional task performance, in response to ROB+ML, FES+ML, and ML alone, in an intensive and long-duration intervention, and no group difference was found. Additional study is warranted to determine the effectiveness of these methods in the clinical setting.
via Comparison of Robotics, FES, and Motor Learning Methods for Treatment of Persistent Upper Extremity Dysfunction after Stroke: a Randomized Controlled Trial – Archives of Physical Medicine and Rehabilitation.
[ARTICLE] Paretic Upper Extremity Movement Gains Are Retained 3 Months After Training With an Electrical Stimulation Neuroprosthesis – Full Text
…This is the first study of which we are aware showing retention of UE motor changes after RTP using ESN. Similarly, some studies suggest retention of paretic UE motor changes associated with participation in constraint-induced movement therapy,16, 17 and a modified constraint-induced therapy regimen.18 The ESN’s use of RTP and progression toward subjects’ motor goals bears some resemblance to both of the above regimens, while the home-based nature of the ESN intervention more closely resembles the modified constraint-induced therapy intervention. However, the constraint-induced family of therapies also differs from ESN in that it: (1) requires participation in many more hours per day of practice than ESN; and (2) necessitates that subjects exhibit more active distal movement than was required for the herein-described ESN intervention. Nonetheless, the finding that motor changes rendered by these approaches are retained months after the intervention period has concluded is likely to affect future practice and reimbursement patterns, as well as conceptions regarding the longer-term potency of stroke behavioral interventions. The longer-term potency associated with an ESN regimen that is mostly home-based may fulfill gaps associated with diminishing contact time and resources available for clinical rehabilitative care…
Paretic Upper Extremity Movement Gains Are Retained 3 Months After Training With an Electrical Stimulation Neuroprosthesis
…Subjects exhibited no changes in the various functional tests, indicating that changes in paretic UE movement realized through RTP using ESN appear to be retained 3 months after the intervention has concluded. This was the first study to our knowledge to examine the longer-term effects of RTP using an ESN in any population…