- •Patients with upper limb post-stroke spasticity were treated with botulinum toxin.
- •Central effects of spasticity treatment were studied using functional MRI.
- •Brain activation pattern was assessed during passive hand movements.
- •BoNT-induced spasticity relief is associated with changes in sensorimotor network.
Posts Tagged sensorimotor
[ARTICLE] Parietal operculum and motor cortex activities predict motor recovery in moderate to severe stroke – Full Text
While motor recovery following mild stroke has been extensively studied with neuroimaging, mechanisms of recovery after moderate to severe strokes of the types that are often the focus for novel restorative therapies remain obscure. We used fMRI to: 1) characterize reorganization occurring after moderate to severe subacute stroke, 2) identify brain regions associated with motor recovery and 3) to test whether brain activity associated with passive movement measured in the subacute period could predict motor outcome six months later.
Because many patients with large strokes involving sensorimotor regions cannot engage in voluntary movement, we used passive flexion-extension of the paretic wrist to compare 21 patients with subacute ischemic stroke to 24 healthy controls one month after stroke. Clinical motor outcome was assessed with Fugl-Meyer motor scores (motor-FMS) six months later. Multiple regression, with predictors including baseline (one-month) motor-FMS and sensorimotor network regional activity (ROI) measures, was used to determine optimal variable selection for motor outcome prediction. Sensorimotor network ROIs were derived from a meta-analysis of arm voluntary movement tasks. Bootstrapping with 1000 replications was used for internal model validation.
During passive movement, both control and patient groups exhibited activity increases in multiple bilateral sensorimotor network regions, including the primary motor (MI), premotor and supplementary motor areas (SMA), cerebellar cortex, putamen, thalamus, insula, Brodmann area (BA) 44 and parietal operculum (OP1-OP4). Compared to controls, patients showed: 1) lower task-related activity in ipsilesional MI, SMA and contralesional cerebellum (lobules V-VI) and 2) higher activity in contralesional MI, superior temporal gyrus and OP1-OP4. Using multiple regression, we found that the combination of baseline motor-FMS, activity in ipsilesional MI (BA4a), putamen and ipsilesional OP1 predicted motor outcome measured 6 months later (adjusted-R2 = 0.85; bootstrap p < 0.001). Baseline motor-FMS alone predicted only 54% of the variance. When baseline motor-FMS was removed, the combination of increased activity in ipsilesional MI-BA4a, ipsilesional thalamus, contralesional mid-cingulum, contralesional OP4 and decreased activity in ipsilesional OP1, predicted better motor outcome (djusted-R2 = 0.96; bootstrap p < 0.001).
In subacute stroke, fMRI brain activity related to passive movement measured in a sensorimotor network defined by activity during voluntary movement predicted motor recovery better than baseline motor-FMS alone. Furthermore, fMRI sensorimotor network activity measures considered alone allowed excellent clinical recovery prediction and may provide reliable biomarkers for assessing new therapies in clinical trial contexts. Our findings suggest that neural reorganization related to motor recovery from moderate to severe stroke results from balanced changes in ipsilesional MI (BA4a) and a set of phylogenetically more archaic sensorimotor regions in the ventral sensorimotor trend. OP1 and OP4 processes may complement the ipsilesional dorsal motor cortex in achieving compensatory sensorimotor recovery.
This talk was given at the BCI Meeting 2016 at Asilomar Conference Grounds on May 31st, 2016.
[Letter to the Editor] Brief history of transcranial direct current stimulation (tDCS): from electric fishes to microcontrollers | Cambridge Core
Electrical stimulation to treat medical conditions is not a new therapy; it has been used to treat diseases for centuries. The first electricity sources used for electrical stimulation were produced by animal electricity. Antique Egyptians knew about the electrical proprieties of Nile catfish, but it is unclear if (and how) they experimented with them for clinical purposes. The first reported evidence of electrical stimulation arrives some centuries later in antique Greece times, when Plato and Aristotle described the ability of the torpedo fish to generate curative effects by its electric discharges (Althaus, 1873; Rockwell, 1896; Harris, 1908).
The first evidence of transcranial stimulation in history comes in Roman Empire times, when Scribonius Largus (the physician of the Roman Emperor Tiberius Claudius Nero Caesar) described how placing a live torpedo fish over the scalp could relieve headache in a patient (Scribonius Largus, 1529). Perhaps the first person known to have been cured by torpedo fish electricity was Anthero, a freed slave of Tiberius Caesar, who suffered gutta (probably gout) (Cambridge, 1977). In the late 11th century, the Muslim physician in Persia, Ibn-Sidah also suggested the use of torpedo fishes to treat epilepsy (Priori, 2003), placing the live catfish on the brows of the patients (Delbourgo, 2006). The use of electric fish stimulation also spread to Africa, where Jesuit missionaries in early modern Abyssinia (Ethiopia) reported that locals used catfishes as a method of expelling ‘Devils out of the human body’ (Delbourgo, 2006). Fish electricity was maybe the most popular type of electrical stimulation for more than 10 centuries though it is not clear how the effects were measured.
In 1660 the German scientist Otto von Guericke invented the first electrostatic generator (Comroe & Dripps, 1976), a frictional crank-controlled machine. This device could be considered the first stimulator device and its variations were used later by scientists like the Italian anatomist Leopoldo Marco Antonio Caldani in 1756 to stimulate muscles in sheep and frogs (Caldani, 1760). The Middlesex Hospital (England) was probably the first hospital to purchase an electrostatic machine in 1767 (Cambridge, 1977).
In 1745 Ewald Georg von Kleist invented the Leyden jar, the first capacitor in history (Keithley, 1999). This device could store electric charge produced from an electrostatic generator. Experimenters, like Anton de Haen in 1755 (Priestley, 1767) and Benjamin Franklin in 1757 (Franklin, 1757), were able to combine electrostatic generators and the Leyden jar for therapeutic electrification (McWhirter et al. 2015).
In 1773 the anatomist and physiologist John Hunter studied the torpedo fish thoroughly. These investigations were undertaken at the request of John Walsh, who showed that the ‘shocks’ produced by the torpedo fish were caused by the generation of electricity (Walsh, 1773). These kind of animals or fishes have an electric organ that, on brain command, generate a three-dimensional dipole field around their bodies, discharging single-cycle pulses from below 1 Hz to about 65 Hz at rest (Hopkins, 2009). Electric fish electricity is not direct current (DC); nevertheless it is the first reported kind of stimulation in history.
Unlike fish electricity and electrostatic electricity, DC is the flow of electrical charge that does not vary with time, generating a constant signal (Belove & Drossman, 1976). The birth of the DC generator was in the 1st century BC with the so-called Baghdad battery, attributed to the ancient Persian civilization (Scrosati, 2011), but other references attribute the invention to the Parthians, calling it the Parthian galvanic cell (Keyser, 1993). This invention remained forgotten until the 20th century, when the archeologist Wilhelm Köning discovered it in Iraq and it was possibly used for medical purposes. In the 18th century Luigi Galvani invented a DC battery (galvanic battery) and his nephew, Giovanni Aldini, was one of the first persons to utilize DC for clinical applications. Aldini’s most detailed account of DC clinical treatment concerns Luigi Lanzarini, a 27-year-old farmer suffering from melancholy madness (major depression), who had been committed to Santo Orsola Hospital, in Bologna, Italy on 17 May 1801, but first assessing the effects of galvanic currents on his own head (Fitzgerald, 2014). The patient’s mood progressively improved so that Lazarini was apparently completely cured several weeks after the beginning of the treatment (Parent, 2004).
Aldini’s work was the milestone which began the era of DC stimulation for neurological and psychiatric conditions. Later in 1802, Hellwag and Jacobi reported the use of transcranial DC, also reporting the first evidence of phosphenes using DC (Hellwag & Jacobi, 1802; Paulus, 2010). Around 1880 the application of brain stimulation treatments on patients was particularly popular among German psychiatrists, pioneers in electrotherapy, an early tDCS method. Wilhelm Tigges, Rudolph Gottfried Arndt (Steinberg, 2013a ) and Erb (1883) tried to establish clear rules on the most beneficial application methods and doses in order to investigate which results it may produce and under what circumstances (Steinberg, 2014). The experimental designs with larger groups in electric therapy research protocols were a common factor in this age. For example, Arndt used 12 psychotic patients in his 1870 experiment. Despite being very detailed, Arndt’s reports do not provide exact data about the strength of the applied current. Due to controversial reports (some with positive results and others with negative) and the lack of understanding of operating principles, electrotherapy was repeatedly suspected of attaining result through suggestion only (Steinberg, 2013a ). Many other researchers used DC for the treatment of mental disorders during the 19th century and the early part of the 20th century, but the variation of procedures, unclear descriptions, few qualitative details and the misunderstood effect of polarization led to variable and/or inconclusive results. The use of DC stimulation was abandoned from the 1930s (Steinberg, 2013b ).
In 1957 DC reappeared in electrosleep therapy and around 1960–1963 electro-anesthesia research incorporated DC bias. In 1964, motivated by animal studies that reported lasting changes in excitability using prolonged scalp DC stimulation, Lippold and Redfearn used 50–500 µA DC currents in 32 healthy subjects, and reported that anodal current induced an increase in alertness, mood and motor activity, whereas cathodal polarization induced quietness and apathy (Lippold & Redfearn, 1964; Guleyupoglu et al. 2013). Despite several follow-up research works, from the 1970s DC stimulation was once again abandoned, probably due to the introduction of new psychiatric drugs (Dubljević et al. 2014).
It was not until 1998 when the usage of DC was advocated and the modern tDCS was born, when Priori and his colleagues investigated the influence of DC in the brain by testing its effects on cerebral cortex excitability using transcranial magnetic stimulation (Brunoni et al. 2012). Characteristics of tDCS, such as the fact that it is non-invasive, mostly well tolerated and its mild adverse effects, have sparked great interest and increase in clinical studies recently (Brunoni et al. 2012).
The transcranial DC stimulators have evolved from a simple galvanic battery in the 18th and 19th centuries, passing from vacuum tubes and transistors to microprocessors and microcontroller technologies in the 20th century. Progress in microcontroller technology has enabled electronic and biomedical engineers to build precise tDCS devices with a better control of stimulation parameters (Paulus & Opitz, 2013) at reduced costs. The future tDCS designs will focus on obtaining simple systems by way of reducing size, power consumption, weight and enhanced portability (Kouzani et al. 2016).
The tDCS is a promising tool for basic neuroscientists, clinical neurologists and psychiatrists in their quest to causally probe cortical representations of sensorimotor and cognitive functions, to facilitate the treatment of various neuropsychiatric disorders (Schlaug & Renga, 2008) and enhance neurological functions in healthy humans (Dubljević et al. 2014). Although tDCS has demonstrated benefits, the scientific community must communicate carefully about their findings, by providing neutral data to the media and public, since the popular media sometimes consider tDCS as a ‘miracle device’ (Riggall et al. 2015). Such sensationalistic news about the benefits of tDCS leads people to self-administer stimulation, as we can see in some Internet do-it-yourself tDCS forums (Wexler, 2015).
[ARTICLE] Paired Associative Stimulation using Brain-Computer Interfaces for Stroke Rehabilitation: A Pilot study – Full Text PDF
Conventional therapies do not provide paralyzed patients with closed-loop sensorimotor integration for motor rehabilitation. Paired associative stimulation (PAS) uses braincomputer interface (BCI) technology to monitor patients’ movement imagery in real-time, and utilizes the information to control functional electrical stimulation (FES) and bar feedback for complete sensorimotor closed loop. To realize this approach, we introduce the recoveriX system, a hardware and software platform for PAS. After 10 sessions of recoveriX training, one stroke patient partially regained control of dorsiflexion in her paretic wrist. A controlled group study is planned with a new version of the recoveriX system, which will use a new FES system and an avatar instead of bar feedback.
In conventional rehabilitation therapy, patients are often asked to try to move the paretic limb, or imagine its movement, while a functional electrical stimulator (FES), physiotherapist, or robotic device helps them perform the desired movement. However, if patients cannot perform the movement without help, there is no objective way to determine whether each patient is actually performing the desired motor imagery task. This dissociation between motor commands and sensory feedback may explain why the therapy does not significantly induce the reorganization of the patients’ brain around their lesioned area. To close the feedback loop for paralyzed patients, we used bar feedback and FES based on their motor imagery (MI) –. This paired associative stimulation (PAS) is an important factor for motor recovery –. Neural networks are facilitated when the presynaptic and postsynaptic neurons are both active…
[Abstract] “How Did I Make It?”: Uncertainty about Own Motor Performance after Inhibition of the Premotor Cortex – Journal of Cognitive Neuroscience.
Optimal motor performance requires the monitoring of sensorimotor input to ensure that the motor output matches current intentions. The brain is thought to be equipped with a “comparator” system, which monitors and detects the congruence between intended and actual movement; results of such a comparison can reach awareness.
This study explored in healthy participants whether the cathodal transcranial direct current stimulation (tDCS) of the right premotor cortex (PM) and right posterior parietal cortex (PPC) can disrupt performance monitoring in a skilled motor task.
Before and after tDCS, participants underwent a two-digit sequence motor task; in post-tDCS session, single-pulse TMS (sTMS) was applied to the right motor cortex, contralateral to the performing hand, with the aim of interfering with motor execution. Then, participants rated on a five-item questionnaire their performance at the motor task. Cathodal tDCS of PM (but not sham or PPC tDCS) impaired the participants’ ability to evaluate their motor performance reliably, making them unconfident about their judgments. Congruently with the worsened motor performance induced by sTMS, participants reported to have committed more errors after sham and PPC tDCS; such a correlation was not significant after PM tDCS.
In line with current computational and neuropsychological models of motor control and awareness, the present results show that a mechanism in the PM monitors and compare intended versus actual movements, evaluating their congruence. Cathodal tDCS of the PM impairs the activity of such a “comparator,” disrupting self-confidence about own motor performance.
[Abstract] Sensorimotor modulation by botulinum toxin A in post-stroke arm spasticity: Passive hand movement – Journal of the Neurological Sciences
In post-stroke spasticity, functional imaging may uncover modulation in the central sensorimotor networks associated with botulinum toxin type A (BoNT) therapy. Investigations were performed to localize brain activation changes in stroke patients treated with BoNT for upper limb spasticity using functional magnetic resonance imaging (fMRI).
Seven ischemic stroke patients (4 females; mean age 58.86) with severe hand paralysis and notable spasticity were studied. Spasticity was scored according to the modified Ashworth scale (MAS). fMRI examination was performed 3 times: before (W0) and 4 (W4) and 11 weeks (W11) after BoNT. The whole-brain fMRI data were acquired during paced repetitive passive movements of the plegic hand (flexion/extension at the wrist) alternating with rest. Voxel-by-voxel statistical analysis using the General Linear Model (GLM) implemented in FSL (v6.00)/FEAT yielded group session-wise statistical maps and paired between-session contrasts, thresholded at the corrected cluster-wise significance level of p < 0.05.
As expected, BoNT transiently lowered MAS scores at W4. Across all the sessions, fMRI activation of the ipsilesional sensorimotor cortex (M1, S1, and SMA) dominated. At W4, additional clusters transiently emerged bilaterally in the cerebellum, in the contralesional sensorimotor cortex, and in the contralesional occipital cortex. Paired contrasts demonstrated significant differences W4 > W0 (bilateral cerebellum and contralesional occipital cortex) and W4 > W11 (ipsilesional cerebellum and SMA). The remaining paired contrast (W0 > W11) showed activation decreases mainly in the ipsilesional sensorimotor cortex (M1, S1, and SMA).
The present study confirms the feasibility of using passive hand movements to map the cerebral sensorimotor networks in patients with post-stroke arm spasticity and demonstrates that BoNT-induced spasticity relief is associated with changes in task-induced central sensorimotor activation, likely mediated by an altered afferent drive from the spasticity-affected muscles.
[ARTICLE] Effects of Functional Limb Overloading on Symmetrical Weight Bearing, Walking Speed, Perceived Mobility, and Community Participation among Patients with Chronic Stroke – Full Text HTML
Background. Stroke is a leading cause for long-term disability that often compromises the sensorimotor and gait function accompanied by spasticity. Gait abnormalities persist through the chronic stages of the condition and only a small percentage of these persons are able to walk functionally in the community.
Material and Method. Patients with chronic stroke were recruited from outpatient rehabilitation unit at Department of Neurology & Neurosurgery, All India Institute of Medical Sciences, having a history of first stroke at least six months before recruitment, with unilateral motor deficits affecting gait. The patients were randomly assigned to either the functional limb overloading (FLO) or Limb Overloading Resistance Training (LORT) group and provided four weeks of training.
Result. We found that there was an improvement in gait performance, weight bearing on affected limb, and perceived mobility and community participation.
Conclusion. To the best of our knowledge, this is the first study that has evaluated the effects of functional limb overloading training on symmetric weight bearing, walking ability, and perceived mobility and participation in chronic hemiplegic population. The study demonstrated a beneficial effect of training on all the outcomes, suggesting that the functional limb overloading training can be a useful tool in the management of gait problems in chronic stroke patients.
Stroke is becoming a rapidly increasing problem and an important cause of disability and deaths worldwide. Incidence and prevalence of strokes in Saudi Arabia are comparatively lower than western countries, which could be because of the predominance of the younger age groups in this region . The annual stroke incidence ranged from 27.5 to 63 per 100,000 population and prevalence ranged from 42 to 68 per 100,000 population .
Stroke is a leading cause for long-term disability due to compromised sensorimotor function. Approximately 85% of stroke survivors learn to walk independently by 6 months after stroke, but gait abnormalities persist throughout the chronic stages of the condition. Only a small percentage of stroke survivors are able to walk functionally in the community [3, 4].
The objective of stroke rehabilitation is to enable individual patients to maximize benefits from training in order to attain the highest possible degree of physical and psychological performance. The ultimate goals for many stroke patients are to achieve a level of functional independence necessary for returning home and to integrate as fully as possible into community life.
Ng and Hui-Chan  have noted that weakness in hemiplegic stroke patients is sometimes overshadowed over concerns about treatment of spasticity and synergistic movements. Studies have revealed positive correlations between the strength of specific muscle groups and a variety of functional attributes . Furthermore, a nonlinear relationship between walking performance and muscle strength in the lower extremities has been suggested . However, as the protocols were multifaceted, it was not possible to determine the precise role that the strength-training component may have played in improving walking function.
A number of studies have shown that task specificity and intensity of training are the main determinants of functional improvement after stroke [6, 8, 9]. Moreover, there is growing evidence suggesting that intensive task-oriented practice can induce greater improvement in walking competency than usual practice in stroke survivors [10–12].
Yang et al.  in their study on stroke patients undergoing progressive lower limb strengthening using functional weight bearing activities found moderate increases in walking speed. Sullivan et al.  found that task-specific training with body-weight support is more effective in improving walking speed but lower limb strength training did not provide any added benefit to walking outcomes.
A major limitation to the conclusions from these studies and systematic reviews is the lack of consistency in the intervention and specified protocols [15–17]. Despite the number of studies dedicated to task-oriented training, none of these studies had combined functional task training with prolonged resistance in the form of limb overloading applied 90% of the awake time. Therefore, we designed this study to address the evidence related to our training protocol to enhance symmetric weight bearing and walking speed and its impact on perceived mobility and community participation in patients with chronic stroke.
We hypothesized that intervention programs that combine lower limb overload with functional task training would be more effective at improving walking outcomes and community participation than lower limb overload training alone.
The design of our study was influenced by the literature on lower extremity strength training and task-specific locomotor training [14, 18, 19]. The use of this design should provide…
[ARTICLE] Study of multi-sensory stimulation for the design of hand rehabilitation equipment for stroke patients
Stroke has long been a critical health issue in adults, affecting their physical, cognitive, and emotional functioning.
The purpose of this study was to develop hand rehabilitation equipment based on multi-sensory stimulation therapy for stroke patients. An experiment was conducted with seventeen professional occupational therapists (each having more than five years of work experience) who individually evaluated the effectiveness of hand rehabilitation using seven hand gestures with two treatment approaches (top-down and bottom-up) and their corresponding six rehabilitation techniques (top-down: mirror therapy and auditory stimulation; bottom-up: tactile stimulation, thermal stimulation, electrical stimulation, and vibration stimulation). Our study used a within-subject partial hierarchical design, where rehabilitation techniques were partially nested within treatment approaches and crossed with hand gestures.
Analyses of the three-way factorial analysis of variance showed that rehabilitation technique had a significant effect and that vibration stimulation and mirror therapy were most effective.
Based on the findings of this study, multi-sensory stimulation equipment (combining vibration stimulation and mirror therapy) was designed to improve the sensorimotor ability of stroke patients.
[REVIEW] Upper Extremity Interventions | EBRSR – Evidence-Based Review of Stroke Rehabilitation – Full Text PDF
Upper extremity complications are common following stroke and may be seriously debilitating. Regaining mobility in the upper extremities is often more difficult than in lower extremities, which can seriously impact the progress of rehabilitation. A large body of research exists around upper extremity complications but debate continues regarding the timing of treatment and adequate prognostic factors. This review provides current information regarding upper extremity interventions. Topics include robotic devices for movement therapy, virtual reality technology, spasticity treatment, EMG/biofeedback, transcutaneous electrical nerve stimulation, functional electric stimulation, and hand edema treatment. Neurodevelopmental upper extremity therapy techniques are reviewed along with repetitive/task-specific training, sensorimotor interventions, hand splinting and constraint induced movement therapy.
…Innovative technologies for sensorimotor rehabilitation after stroke have dramatically increased these past 20 years. Based on a review of the literature on “Medline” and “Web of Science” between 1990 and 2013, we offer an overview of available tools and their current level of validation…