Restorative Neurology and Neuroscience - Volume 34, issue 4

Article Type: Other

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 465-465, 2016

Authors: Hamilton, Roy H.

Article Type: Introduction

DOI: 10.3233/RNN-169002

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 467-471, 2016

Authors: Sebastian, Rajani | Long, Charltien | Purcell, Jeremy J. | Faria, Andreia V. | Lindquist, Martin | Jarso, Samson | Race, David | Davis, Cameron | Posner, Joseph | Wright, Amy | Hillis, Argye E.

Article Type: Research Article

Abstract: Purpose: The neural mechanisms that support aphasia recovery are not yet fully understood. Our goal was to evaluate longitudinal changes in naming recovery in participants with posterior cerebral artery (PCA) stroke using a case-by-case analysis. Methods: Using task based and resting state functional magnetic resonance imaging (fMRI) and detailed language testing, we longitudinally studied the recovery of the naming network in four participants with PCA stroke with naming deficits at the acute (0 week), sub acute (3–5 weeks), and chronic time point (5–7 months) post stroke. Behavioral and imaging analyses (task related and resting state functional connectivity) …were carried out to elucidate longitudinal changes in naming recovery. Results: Behavioral and imaging analysis revealed that an improvement in naming accuracy from the acute to the chronic stage was reflected by increased connectivity within and between left and right hemisphere “language” regions. One participant who had persistent moderate naming deficit showed weak and decreasing connectivity longitudinally within and between left and right hemisphere language regions. Conclusions: These findings emphasize a network view of aphasia recovery, and show that the degree of inter- and intra- hemispheric balance between the language-specific regions is necessary for optimal recovery of naming, at least in participants with PCA stroke. Show more

Keywords: PCA stroke, aphasia, longitudinal recovery, fMRI, naming network

DOI: 10.3233/RNN-150621

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 473-489, 2016

Authors: Turkeltaub, Peter E. | Swears, Mary K. | D’Mello, Anila M. | Stoodley, Catherine J.

Article Type: Research Article

Abstract: Background : Aphasia is an acquired deficit in the ability to communicate through language. Noninvasive neuromodulation offers the potential to boost neural function and recovery, yet the optimal site of neuromodulation for aphasia has yet to be established. The right posterolateral cerebellum is involved in multiple language functions, interconnects with left-hemisphere language cortices, and is crucial for optimization of function and skill acquisition, suggesting that cerebellar neuromodulation could enhance aphasia rehabilitation. Objective : To provide preliminary behavioral and functional connectivity evidence from healthy participants that cerebellar neuromodulation may be useful for rehabilitation of aphasia. Methods : In Experiment …1, 76 healthy adults performed articulation and verbal fluency tasks before and after anodal, cathodal or sham transcranial direct current stimulation (tDCS) was applied over two cerebellar locations (anterior, right posterolateral). In Experiment 2, we examined whether anodal tDCS over the right posterolateral cerebellum modulated resting-state functional connectivity in language networks in 27 healthy adults. Results : TDCS over the right posterolateral cerebellum significantly improved phonemic fluency. Cerebellar neuromodulation increased functional connectivity between the cerebellum and areas involved in the motor control of speech, and enhanced the correlations between left-hemisphere language and speech-motor regions. Conclusion : We provide proof-of-principle evidence that cerebellar neuromodulation improves verbal fluency and impacts resting-state connectivity in language circuits. These findings suggest that the cerebellum is a viable candidate for neuromodulation in people with aphasia. Show more

Keywords: Aphasia, cerebellum, transcranial direct current stimulation (tDCS), language, neuromodulation, resting-state fMRI

DOI: 10.3233/RNN-150633

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 491-505, 2016

Authors: Thiel, Alexander | Zumbansen, Anna

Article Type: Research Article

Abstract: Background: Post-stroke aphasia syndromes as a clinical entity arise from the disruption of brain networks specialized in language production and comprehension due to permanent focal ischemia. This approach to post-stroke aphasia is based on two pathophysiological concepts: 1) Understanding language processing in terms of distributed networks rather than language centers and 2) understanding the molecular pathophysiology of ischemic brain injury as a dynamic process beyond the direct destruction of network centers and their connections. While considerable progress has been made in the past 10 years to develop such models on a systems as well as a molecular level, the …influence of these approaches on understanding and treating clinical aphasia syndromes has been limited. Objective & Methods: In this article, we review current pathophysiological concepts of ischemic brain injury, their relationship to altered information processing in language networks after ischemic stroke and how these mechanisms may be influenced therapeutically to improve treatment of post-stroke aphasia. Conclusion: Understanding the pathophysiological mechanism of post-stroke aphasia on a neurophysiological systems level as well as on the molecular level becomes more and more important for aphasia treatment, as the field moves from standardized therapies towards more targeted individualized treatment strategies comprising behavioural therapies as well as non-invasive brain stimulation (NIBS). Show more

Keywords: Aphasia, ischemic stroke, language network, pathophysiology of stroke, speech and language therapy, transcranial magnetic stimulation, transcranial direct current stimulation

DOI: 10.3233/RNN-150632

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 507-518, 2016

Authors: Zheng, Xin | Dai, Weiying | Alsop, David C. | Schlaug, Gottfried

Article Type: Research Article

Abstract: Background/Objective: Transcranial direct current stimulation (tDCS) can enhance or diminish cortical excitability levels depending on the polarity of the stimulation. One application of non-invasive brain-stimulation has been to modulate a possible inter-hemispheric disinhibition after a stroke. This disinhibition model has been developed mainly for the upper extremity motor system, but it is not known whether the language/speech-motor system shows a similar inter-hemispheric interaction. We aimed to examine physiological evidence of inter- and intra-hemispheric connectivity changes induced by tDCS of the right inferior frontal gyrus (IFG) using arterial-spin labeling (ASL) MRI. Methods: Using an MR-compatible DC-Stimulator, we applied …anodal stimulation to the right IFG region of nine healthy adults while undergoing non-invasive cerebral blood flow imaging with arterial-spin labeling (ASL) before, during, and after the stimulation. All ASL images were then normalized and timecourses were extracted in regions of interest (ROIs), which were the left and right IFG regions, and the right supramarginal gyrus (SMG) in the inferior parietal lobule. Two additional ROIs (the right occipital lobe and the left fronto-orbital region) were taken as control regions. Results: Using regional correlation coefficients as a surrogate marker of connectivity, we could show that inter-hemispheric connectivity (right IFG with left IFG) decreased significantly (p  < 0.05; r-scores from 0.67 to 0.53) between baseline and post-stimulation, while the intra-hemispheric connectivity (right IFG with right SMG) increased significantly (p  < 0.05;r-scores from 0.74 to 0.81). A 2 × 2 ANOVA found a significant main effect of HEMISPHERE (F(8) = 6.83, p  < 0.01) and a significant HEMISPHERE-by-TIME interaction (F(8) = 4.24, p  < 0.05) in connectivity changes. The correlation scores did not change significantly in the control region pairs (right IFG with right occipital and right IFG with left fronto-orbital) over time. Conclusion: Using an MR-compatible DC stimulator we showed that ASL-MRI can detect tDCS-induced modulation of brain connectivity within and between hemispheres. These findings might affect trial designs focusing on modulating the non-dominant hemisphere to enhance language/speech-motor functions. Show more

Keywords: Resting state fcMRI, arterial spin labeling, tDCS, transcallosal connectivity, aphasia, rehabilitation, brainstimulation, plasticity

DOI: 10.3233/RNN-150625

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 519-530, 2016

Authors: Heiss, Wolf-Dieter

Article Type: Research Article

Abstract: The functional deficit after a focal brain lesion is determined by the localization and the extent of the tissue damage. Since destroyed tissue usually cannot be replaced in the adult human brain, improvement or recovery of neurological deficits can be achieved only by reactivation of functionally disturbed but morphologically preserved areas or by recruitment of alternative pathways within the functional network. The visualization of disturbed interaction in functional networks and of their reorganization in the recovery after focal brain damage is the domain of functional imaging modalities such as positron emission tomography (PET). Longitudinal assessments at rest and during activation …tasks during the early and later periods following a stroke can demonstrate recruitment and compensatory mechanisms in the functional network responsible for complete or partial recovery of disturbed functions. Imaging studies have shown that improvements after focal cortical injury are represented over larger cortical territories. It has also been shown that the unaffected hemisphere in some instances actually inhibits the recovery of ipsilateral functional networks and this effect of transcallosal inhibition can be reduced by non-invasive brain stimutation. Non-invasive brain stimulation (NIBS) can modulate the excitability and activity of targeted cortical regions and thereby alter the interaction within pathologically affected functional networks; this kind of intervention might promote the adaptive cortical reorganization of functional networks after stroke. In poststroke aphasia several studies attempted to restore perilesional neuronal activity in the injured left inferior frontal gyrus by applying excitatory high frequency repetitive transcranial magnetic stimulation (rTMS) or intermittent theta burst stimulation (iTBS) or anodal transcranial direct current stimulation (tDCS), but most NIBS studies in poststroke aphasia employed inhibitory low frequency rTMS for stimulation of the contralesional pars triangularis of the right inferior frontal gyrus (BA 45) in order to reduce right hemisphere hyperactivity and transcallosal inhibition on the left Broca’s area. While most studies reported single cases or small case series with chronic poststroke aphasia without any control condition, only a few controlled studies including sham stimulation were performed in chronic stage after stroke. In one controlled randomized study changes in PET activation pattern in the subacute course were related to the clinical improvement. In this “proof-of-principle” study the shift of the activation pattern to the dominant hemisphere induced by inhibitory rTMS over the right inferior frontal gyrus could be demonstrated in the PET activation studies and correlated to improved performance in aphasia tests. NIBS might be a treatment strategy which could improve the effect of other rehabilitative efforts. Show more

Keywords: Non-invasive brain stimulation, repetitive transcranial magnetic stimulation, positron emission tomography, aphasia, stroke

DOI: 10.3233/RNN-150631

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 531-536, 2016

Authors: Shah-Basak, Priyanka P. | Wurzman, Rachel | Purcell, Juliann B. | Gervits, Felix | Hamilton, Roy

Article Type: Research Article

Abstract: Purpose: Aphasia—acquired loss of the ability to understand or express language—is a common and debilitating neurological consequence of stroke. Evidence suggests that transcranial magnetic (TMS) or direct current stimulation (tDCS) can significantly improve language outcomes in patients with aphasia (PWA). However, the relative efficacy between TMS and tDCS has not yet been explored. Mechanistic and methodological differences, patient inclusion/exclusion criteria and experimental designs may influence observed treatment benefits. Methods: We conducted a systematic review and meta-analyses of TMS and tDCS treatment studies in PWA. Standard mean difference (SMD) for changes in picture naming accuracy was estimated; pooled …SMDs were compared using a random-effects model. Results: Eight TMS (N  = 143) and 8 tDCS studies (N  = 140) met our inclusion criteria. Pooled SMDs of 0.448 (p  < 0.001) in favor of TMS, and 0.395 (p  < 0.001) in favor of tDCS were found. Between-subject designs were more common in subacute and within/crossover designs in chronic patients. TMS SMDs were significant in both chronic (SMD = 0.348) and subacute (SMD = 0.667) populations while those for tDCS were significant in chronic (SMD = 0.320) but not in subacute (SMD = 0.283) PWA. Conclusions: The magnitude of treatment effects appears to be consistent between TMS and tDCS in PWA. Larger-scale clinical trials should further substantiate our findings. Show more

Keywords: rTMS, tDCS, neurorehabilitation, neuroplasticity, meta-analysis, stroke, aphasia, language recovery

DOI: 10.3233/RNN-150616

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 537-558, 2016

Article Type: Other

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 559-559, 2016

Authors: Werner, Cordula | Byhahn, Manuela | Hesse, Stefan

Article Type: Research Article

Abstract: Purpose: In order to promote alertness and awareness in patients with severe disorders of consciousness (DOC) frontal near infrared laser stimulation (N-LT) or transcranial focused shock wave therapy (F-SWT) might be an option. The study compared both techniques in severe chronic DOC patients. Methods: Sixteen DOC patients were allocated to two groups (A and B). A three week baseline either followed a frontal N-LT (0,1 mJ/mm2 , 10 min per session), five times a week over four weeks (group A), or a F-SWT (0,1 mJ/mm2 , 4000 stimuli per session) three times a week over four weeks (group B). The …primary variable was the revised Coma Recovery Scale (r-CRS, 0–23), blindly assessed. Results: Both groups improved in the r-CRS over time, but revealed no differences between groups. One patient of group B had a focal seizure in the third therapy week. One patient with akinetic mutism improved most and three patients with global hypoxia did not improve at all. Conclusions: Both options might be an option to increase alertness and awareness of chronic DOC patients. An akinetic mutism seems to be a positive and severe cerebral hypoxia a negative predictor. Epileptic seizures are a potential unwanted side effect. More clinical studies are warranted. Show more

Keywords: Disorder of consciousness, minimal conscious state, unresponsive wakefulness syndrome, non-invasive brain stimulation, laser therapy, focused shock wave therapy

DOI: 10.3233/RNN-150624

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 561-569, 2016

Authors: Bolognini, Nadia | Russo, Cristina | Edwards, Dylan J.

Article Type: Research Article

Abstract: Contemporary strategies to promote motor recovery following stroke focus on repetitive voluntary movements. Although successful movement relies on efficient sensorimotor integration, functional outcomes often bias motor therapy toward motor-related impairments such as weakness, spasticity and synergies; sensory therapy and reintegration is implied, but seldom targeted. However, the planning and execution of voluntary movement requires that the brain extracts sensory information regarding body position and predicts future positions, by integrating a variety of sensory inputs with ongoing and planned motor activity. Neurological patients who have lost one or more of their senses may show profoundly affected motor functions, even if muscle …strength remains unaffected. Following stroke, motor recovery can be dictated by the degree of sensory disruption. Consequently, a thorough account of sensory function might be both prognostic and prescriptive in neurorehabilitation. This review outlines the key sensory components of human voluntary movement, describes how sensory disruption can influence prognosis and expected outcomes in stroke patients, reports on current sensory-based approaches in post-stroke motor rehabilitation, and makes recommendations for optimizing rehabilitation programs based on sensory stimulation. Show more

Keywords: Stroke, motor recovery, sensory stimulation, motor rehabilitation, sensorimotor integration, non-invasive brain stimulation

DOI: 10.3233/RNN-150606

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 571-586, 2016

Authors: Tremblay, Sara | Lafleur, Louis-Philippe | Proulx, Sébastien | Beaulé, Vincent | Latulipe-Loiselle, Alex | Doyon, Julien | Marjańska, Małgorzata | Théoret, Hugo

Article Type: Research Article

Abstract: Purpose: The aim of the present study was to assess, in healthy individuals, the impact of M1-M1 tDCS on primary motor cortex excitability using transcranial magnetic stimulation and sensorimotor metabolite concentration using 1 H-MRS. Methods: For both experiments, each participant received the three following interventions (20 min tDCS, 1 mA): left-anodal/right-cathodal, left-cathodal/right-anodal, sham. The effects of tDCS were assessed via motor evoked potentials (experiment 1) and metabolite concentrations (experiment 2) immediately after and 12 minutes following the end of stimulation and compared to baseline measurement. Results: No effect of M1-M1 tDCS on corticospinal excitability was found. Similarly, …M1-M1 tDCS did not significantly modulate metabolite concentrations. High inter-subject variability was noted. Response rate analysis showed a tendency towards inhibition following left-anodal/right-cathodal tDCS in 50% of participants and increased GABA levels in 45% of participants. Conclusion: In line with recent studies showing important inter-subject variability following M1-supraorbital tDCS, the present data show that M1-M1 stimulation is also associated with large response variability. The absence of significant effects suggests that current measures may lack sensitivity to assess changes in M1 neurophysiology and metabolism associated with M1-M1 tDCS. Show more

Keywords: Magnetic resonance spectroscopy, transcranial direct current stimulation, motor cortex, GABA, glutamate

DOI: 10.3233/RNN-150569

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 587-602, 2016

Authors: Pazzaglia, Mariella | Haggard, Patrick | Scivoletto, Giorgio | Molinari, Marco | Lenggenhager, Bigna

Article Type: Case Report

Abstract: Purpose: Spinal cord injury (SCI), a profound impairment of sensorimotor functions, is often associated with pain related phenomena, including mechanical allodynia, a condition in which non-painful tactile sensation is perceived as pain. Pain and somatic sensation are undeniable markers of normal bodily awareness. However, the mechanism by which they are integrated into a coherent sense of the bodily self remains largely unclear. In this study, we investigated the effect of high-level multisensory manipulation on subjective experiences of pain, touch, and body-ownership. Methods: We administered visuo-tactile stimulation based on the rubber hand illusion. In a longitudinal study, we …compared the strength of the illusion in a male with SCI, who initially had lost somatosensation in all his fingers, but a few months later reported signs of tactile allodynia restricted to the left C6-dermatome. Results: After the restoration of some somatosensation, even if it were painful, synchronous but not asynchronous visuo-tactile stimulation induced body illusion. Previously painful stimuli were temporarily perceived as less painful, and the patient further regained tactile sensations in adjacent numb areas. Conclusions: The sensations of touch and pain are mutually influenced and inextricably linked to a coherent representation of one’s own body. Multisensory manipulations affecting the perception and representation of the body might thus offer a powerful opportunity to mitigate nociceptive and somatic abnormalities. Show more

Keywords: Bodily illusions, somatosensory perception, pain, allodynia, spinal cord injury, rehabilitation, analgesia

DOI: 10.3233/RNN-150611

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 603-613, 2016

Authors: Huchon, Laure | Badet, Lionel | Roy, Alice Catherine | Finos, Livio | Gazarian, Aram | Revol, Patrice | Bernardon, Laurence | Rossetti, Yves | Morelon, Emmanuel | Rode, Gilles | Farnè, Alessandro

Article Type: Research Article

Abstract: Purpose: Hand allograft has recently emerged as a therapeutic option for upper limb amputees. Functional neuroimaging studies have progressively revealed sensorimotor cortices plasticity following both amputation and transplantation. The purpose of our study was to assess and characterize the functional recovery of the visuo-motor control of prehension in bilateral hand transplanted patients. Methods: Using kinematics recordings, we characterized the performance of prehension with or without visual feed-back for object of different position and size, in five bilateral hand allograft recipients and age-matched control subjects. Both hands were assessed, separately. Results: Despite an overall slower execution, …allografted patients succeeded in grasping for more than 90% of the trials. They exhibited a preserved hand grip scaling according to object size, and preserved prehension performances when tested without visual feedback. These findings highlight the allograft recipients’ abilities to produce an effective motor program, and a good proprioceptive-dependent online control. Nevertheless, the maximum grip aperture was reduced and delayed, the coupling between Transport and Grasp components was altered, and the final phase of the movement was lengthened. Conclusion: Hand allotransplantation can offer recipients a good recovery of the visuo-motor control of prehension, with slight impairments likely attributable to peripheral neuro-orthopedic limitations. Show more

Keywords: Hand transplantation, kinematics, prehension, visuo-motor control, neural plasticity

DOI: 10.3233/RNN-150502

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 615-633, 2016

Authors: Lee, Minji | Park, Chang-hyun | Im, Chang-Hwan | Kim, Jung-Hoon | Kwon, Gyu-Hyun | Kim, Laehyun | Chang, Won Hyuk | Kim, Yun-Hee

Article Type: Research Article

Abstract: Purpose: In brain–computer interfaces (BCIs), electrical brain signals during motor imagery are utilized as commands connecting the brain to a computer. To use BCI in patients with stroke, unique brain signal changes should be characterized during motor imagery process. This study aimed to examine the trial-dependent motor-imagery-related activities in stroke patients. Methods: During the recording of electroencephalography (EEG) signals, 12 chronic stroke patients and 11 age-matched healthy controls performed motor imagery finger tapping at 1.3 sec intervals. Trial-dependent brain signal changes were assessed by analysis of the mu and beta bands. Results: Neuronal activity in healthy …controls was observed over bilateral hemispheres at the mu and beta bands regardless of changes in the trials, whereas neuronal activity in stroke patients was mainly seen over the ipsilesional hemisphere at the beta band. With progression to repeated trials, healthy controls displayed a decrease in cortical activity in the contralateral hemisphere at the mu band and in bilateral hemispheres at the beta band. In contrast, stroke patients showed a decreasing trend in cortical activity only over the ipsilesional hemisphere at the beta band. Conclusions: Trial-dependent changes during motor imagery learning presented in a different manner in stroke patients. Understanding motor imagery learning in stroke patients is crucial for enhancing the effectiveness of motor-imagery-based BCIs. Show more

Keywords: Motor imagery, stroke, electroencephalography, brain-computer interfaces, SPM

DOI: 10.3233/RNN-150534

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 635-645, 2016

Authors: Yang, Liuzhu | Yan, Xinping | Xu, Zunying | Tan, Wei | Chen, Zhong | Wu, Bo

Article Type: Research Article

Abstract: Purpose: A previous study showed that a 1-h delay in treatment of thoracic spinal cord injury (SCI) with recombinant human erythropoietin (rhEPO) lacked neuroprotective efficacy. The aim of the present study was to reassess delayed administration of different doses of rhEPO on acute spinal cord compressive injury in rats. Methods: The experiment was divided into first and second stages, which SCI rats were observed for 4 and 28 days, respectively. All rats were randomly divided into four groups at both stages: control group, and rhEPO-3,000U (Unit), rhEPO-4,000U and rhEPO-5,000U groups. SCI rats received rhEPO treatment at different …time points. The primary indicators were locomotor recovery, histopathology, apoptotic index, inflammatory index, ultrastructural scoring system and volume of areas of demyelination. Results: The most significant locomotor functional and histopathological improvements and the best myelin protection were observed after administration of 5,000 U/kg rhEPO. rhEPO at 3,000, 4,000 and 5,000 U/kg showed similar ultrastructural neuroprotection, as well as similar inhibition of apoptosis and regulation of inflammation. Conclusion: Delayed administration of rhEPO can reduce apoptosis and inflammation, and promote myelin repair and functional recovery following spinal cord compressive injury in rats. Show more

Keywords: Erythropoietin, delayed treatment, spinal cord injury, myelin, functional recovery, rats

DOI: 10.3233/RNN-150498

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 647-663, 2016

Authors: Mammele, Stefan | Frauenknecht, Katrin | Sevimli, Sevgi | Diederich, Kai | Bauer, Henrike | Grimm, Christina | Minnerup, Jens | Schäbitz, Wolf-Rüdiger | Sommer, Clemens J.

Article Type: Research Article

Abstract: Purpose: Using G-CSF deficient mice we recently demonstrated neuroprotective properties of endogenous G-CSF after ischemic stroke. The present follow-up study was designed to check, whether specific alterations in ligand binding densities of excitatory glutamate or inhibitory GABAA receptors may participate in this effect. Methods: Three groups of female mice were subjected to 45 minutes of MCAO: wildtype, G-CSF deficient and G-CSF deficient mice substituted with G-CSF. Infarct volumes were determined after 24 hours and quantitative in vitro receptor autoradiography was performed using [3 H]MK-801, [3 H]AMPA and [3 H]muscimol for labeling of NMDA, AMPA and …GABAA receptors, respectively. Ligand binding densities were analyzed in regions in the ischemic core, peri-infarct areas and corresponding contralateral regions. Results: Infarct volumes did not significantly differ between the experimental groups. Ligand binding densities of NMDA and GABAA receptors were widely in the same range. However, AMPA receptor binding densities in G-CSF deficient mice were substantially enhanced compared to wildtype mice. G-CSF substitution in mice lacking G-CSF largely reversed this effect. Conclusions: Although infarct volumes did not differ 24 hours after ischemia the increase of AMPA receptor binding densities in G-CSF deficient mice may explain the bigger infarcts previously observed at later time-points with the same stroke model. Show more

Keywords: G-CSF, focal ischemia, MCAO, autoradiography, infarct volume, excitotoxicity, AMPA, mouse

DOI: 10.3233/RNN-150543

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 665-675, 2016

Authors: Bashir, Shahid | Vernet, Marine | Najib, Umer | Perez, Jennifer | Alonso-Alonso, Miguel | Knobel, Mark | Yoo, Woo-Kyoung | Edwards, Dylan | Pascual-Leone, Alvaro

Article Type: Research Article

Abstract: Background: The net effect of altered interhemispheric interactions between homologous motor cortical areas after unilateral stroke has been previously reported to contribute to residual hemiparesis. Using this framework, we hypothesized that navigated 1 Hz repetitive transcranial magnetic stimulation (rTMS) over the contralesional hemisphere would induce a stronger physiological and behavioural response in patients with residual motor deficit than in healthy subjects, because an imbalance in interhemispheric excitability may underlie motor dysfunction. Methods: Navigated rTMS was conducted in 8 chronic stroke patients (67.50±13.77 years) and in 8 comparable normal subjects (57.38±9.61 years). We evaluated motor function (Finger tapping, Nine …Hole Peg test, Strength Index and Reaction Time) as well as the excitatory and inhibitory function (resting motor threshold, motor evoked potential amplitude, intra-cortical inhibition and facilitation, and silent period) of the stimulated and non-stimulated motor cortex before and after navigated rTMS. Results: rTMS induced an increase in excitability in the ipsilesional (non-stimulated) motor cortex and led to improved performance in the finger tapping task and pinch force task. These physiological and behavioral effects were more prominent (or robust) in the group of stroke patients than in the control group. Conclusion: Navigated low-frequency rTMS involving precise and consistent targeting of the contralesional hemisphere in stroke patients enhanced the cortical excitability of the ipsilesional hemisphere and the motor response of the hemiparetic hand. Show more

Keywords: Navigated rTMS, rehabilitation, plasticity, cortex excitability, intra-cortical inhibition, motor behavior

DOI: 10.3233/RNN-140460

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 677-689, 2016