Restorative Neurology and Neuroscience - Volume 27, issue 3

Authors: Suárez-Monteagudo, Carlos | Hernández-Ramírez, Porfirio | Álvarez-González, Lázaro | García-Maeso, Iván | de la Cuétara-Bernal, Karelys | Castillo-Díaz, Lázara | Bringas-Vega, María L. | Martínez-Aching, Gilda | Morales-Chacón, Lilia M. | Báez-Martín, Margarita M. | Sánchez-Catasús, Carlos | Carballo-Barreda, Maylen | Rodríguez-Rojas, Rafael | Gómez-Fernández, Lázaro | Alberti-Amador, Esteban | Macías-Abraham, Consuelo | Balea, Elvira Dorticós | Rosales, Lázaro Cortina | del Valle Pérez, Lázaro | Ferrer, Berta B. Socarrás | González, Raúl Macías | Bergado, Jorge A.

Article Type: Research Article

Abstract: Purpose: Bone marrow stem cells (BMSC) were transplanted into the perilesional area in five patients bearing sequels of stroke, to evaluate the safety of the procedure and tolerance to the transplanted cells. Methods: Cells were obtained from bone marrow samples taken from the same patient and stereotactically implanted into the targets, determined using a combination of images, and trans-operative recording of multiunit activity. The cells were implanted in several points along tracts in the …perilesional region. Results: No important adverse events derived from surgery or transplant were observed during the one year follow-up period, or detected using a combination of tests and functional measurements applied pre- and post-surgically. In contrast, some improvements were observed regarding the neurological condition of the patients, but the small number of patients in the study does not allow any conclusive statement. Conclusions: Our results demonstrate that BMSC can be safely transplanted into the brain of patients, with excellent tolerance and without complications, using the methods described here. Show more

DOI: 10.3233/RNN-2009-0483

Citation: Restorative Neurology and Neuroscience, vol. 27, no. 3, pp. 151-161, 2009

Authors: Liu, Mingyue | Dziennis, Suzan | Hurn, Patricia D. | Alkayed, Nabil J.

Article Type: Research Article

Abstract: Biological sex is an important determinant of stroke risk and outcome. Women are protected from cerebrovascular disease relative to men, an observation commonly attributed to the protective effect of female sex hormones, estrogen and progesterone. However, sex differences in brain injury persist well beyond the menopause and can be found in the pediatric population, suggesting that the effects of reproductive steroids may not completely explain sexual dimorphism in stroke. We review recent advances in our understanding …of sex steroids (estradiol, progesterone and testosterone) in the context of ischemic cell death and neuroprotection. Understanding the molecular and cell-based mechanisms underlying sex differences in ischemic brain injury will lead to a better understanding of basic mechanisms of brain cell death and is an important step toward designing more effective therapeutic interventions in stroke. Show more

Keywords: Gender, sex, sexual dimorphism, brain, stroke, ischemia, estrogen, progesterone, testosterone

DOI: 10.3233/RNN-2009-0467

Citation: Restorative Neurology and Neuroscience, vol. 27, no. 3, pp. 163-179, 2009

Authors: Neary, K. | Anand, S. | Hotson, J.R.

Article Type: Research Article

Abstract: Purpose: Visual perceptual learning occurs with the presentation of novel visual stimuli at retinal sites near the fovea to 20° eccentricities. It was unclear if the magnitude and rate of visual learning were similar across the central visual fields or if visual learning decreased with increasing eccentricity. The robustness of learning across the visual fields may affect the magnitude of computer-aided visual recovery after visual brain injury. Therefore we determined if eccentricity was a factor that …influenced perceptual learning. Methods: Subjects were trained to detect the presence or absence of a single line oriented differently (odd-element) from an array of lines that otherwise had the same orientation. The odd-element line was presented 3°, 9° or 18° from fixation. Results: Perceptual performance improved during training trials with a similar magnitude and similar learning curve slopes at all 3 eccentricities. Pre- and post-training performance improved to a similar magnitude at 3 vs 9° in 4 of 4 subjects tested and at 9° vs 18° in 4 of 5 subjects. In the fifth subject there was no post-training improvement in performance at 18°. Conclusion: Visual perceptual learning is similar across the extrafoveal central visual fields in almost all subjects. Show more

Keywords: Visual perceptual learning, neuroplasticity, visual fields, visual recovery

DOI: 10.3233/RNN-2009-0468

Citation: Restorative Neurology and Neuroscience, vol. 27, no. 3, pp. 181-188, 2009

Authors: von Lewinski, Friederike | Hofer, Sabine | Kaus, Jürgen | Merboldt, Klaus-Dietmar | Rothkegel, Holger | Schweizer, Renate | Liebetanz, David | Frahm, Jens | Paulus, Walter

Article Type: Research Article

Abstract: Purpose: EMG-triggered electrostimulation (EMG-ES) may improve the motor performance of affected limbs of hemiparetic stroke patients even in the chronic stage. This study was designed to characterize cortical activation changes following intensified EMG-ES in chronic stroke patients and to identify predictors for successful rehabilitation depending on disease severity. Methods: We studied 9 patients with severe residual hemiparesis, who underwent 8 weeks of daily task-orientated multi-channel EMG-ES of the paretic arm. Before and after treatment, …arm function was evaluated clinically and cortical activation patterns were assessed with functional MRI (fMRI) and/or transcranial magnetic stimulation (TMS). Results: As response to therapy, arm function improved in a subset of patients with more capacity in less affected subjects, but there was no significant gain for those with Box & Block test values below 4 at inception. The clinical improvement, if any, was accompanied by an ipsilesional increase in the sensorimotor cortex (SMC) activation area in fMRI and enhanced intracortical facilitation (ICF) as revealed by paired TMS. The SMC activation change in fMRI was predicted by the presence or absence of motor-evoked potentials (MEPs) on the affected side. Conclusions: The present findings support the notion that intensified EMG-ES may improve the arm function in individual chronic hemiparetic stroke patients but not in more severely impaired individuals. Functional improvements are paralleled by increased ipsilesional SMC activation and enhanced ICF supporting neuroplasticity as contributor to rehabilitation. The clinical score at inception and the presence of MEPs have the best predictive potential. Show more

Keywords: EMG-triggered electrostimulation, stroke, neuroplasticity, TMS, fMRI

DOI: 10.3233/RNN-2009-0469

Citation: Restorative Neurology and Neuroscience, vol. 27, no. 3, pp. 189-197, 2009

Authors: Edwards, D.J. | Krebs, H.I. | Rykman, A. | Zipse, J. | Thickbroom, G.W. | Mastaglia, F.L. | Pascual-Leone, A. | Volpe, B.T.

Article Type: Research Article

Abstract: Anodal transcranial direct current stimulation (tDCS) can transiently increase corticomotor excitability of intrinsic hand muscles and improve upper limb function in patients with chronic stroke. As a preliminary study, we tested whether increased corticomotor excitability would be similarly observed in muscles acting about the wrist, and remain present during robotic training involving active wrist movements, in six chronic stroke patients with residual motor deficit. Methods: Transcranial magnetic stimulation (TMS) generated …motor evoked potentials (MEP) in the flexor carpi radialis (FCR) and provided a measure of corticomotor excitability and short-interval cortical inhibition (SICI) before and immediately after a period of tDCS (1 mA, 20 min, anode and TMS applied to the lesioned hemisphere), and robotic wrist training (1hr). Results: Following tDCS, the same TMS current strength evoked an increased MEP amplitude (mean 168 ± 22%SEM; p < 0.05), that remained increased after robot training (166 ± 23%; p < 0.05). Conditioned MEPs were of significantly lower amplitude relative to unconditioned MEPs prior to tDCS (62 ± 6%, p < 0.05), but not after tDCS (89 ± 14%, p = 0.40), or robot training (91 ± 8%, p = 0.28), suggesting that the increased corticomotor excitability is associated with reduced intracortical inhibition. Conclusion: The persistence of these effects after robotic motor training, indicates that a motor learning and retraining program can co-exist with tDCS-induced changes in cortical motor excitability, and supports the concept of combining brain stimulation with physical therapy to promote recovery after brain injury. Show more

DOI: 10.3233/RNN-2009-0470

Citation: Restorative Neurology and Neuroscience, vol. 27, no. 3, pp. 199-207, 2009

Authors: Adamovich, S.V. | August, K. | Merians, A. | Tunik, E.

Article Type: Research Article

Abstract: Purpose: Emerging evidence shows that interactive virtual environments (VEs) may be a promising tool for studying sensorimotor processes and for rehabilitation. However, the potential of VEs to recruit action observation-execution neural networks is largely unknown. For the first time, a functional MRI-compatible virtual reality system (VR) has been developed to provide a window into studying brain-behavior interactions. This system is capable of measuring the complex span of hand-finger movements and simultaneously streaming …this kinematic data to control the motion of representations of human hands in virtual reality. Methods: In a blocked fMRI design, thirteen healthy subjects observed, with the intent to imitate (OTI), finger sequences performed by the virtual hand avatar seen in 1st person perspective and animated by pre-recorded kinematic data. Following this, subjects imitated the observed sequence while viewing the virtual hand avatar animated by their own movement in real-time. These blocks were interleaved with rest periods during which subjects viewed static virtual hand avatars and control trials in which the avatars were replaced with moving non-anthropomorphic objects. Results: We show three main findings. First, both observation with intent to imitate and imitation with real-time virtual avatar feedback, were associated with activation in a distributed frontoparietal network typically recruited for observation and execution of real-world actions. Second, we noted a time-variant increase in activation in the left insular cortex for observation with intent to imitate actions performed by the virtual avatar. Third, imitation with virtual avatar feedback (relative to the control condition) was associated with a localized recruitment of the angular gyrus, precuneus, and extrastriate body area, regions which are (along with insular cortex) associated with the sense of agency. Conclusions: Our data suggest that the virtual hand avatars may have served as disembodied training tools in the observation condition and as embodied "extensions" of the subject's own body (pseudo-tools) in the imitation. These data advance our understanding of the brain-behavior interactions when performing actions in VE and have implications in the development of observation- and imitation-based VR rehabilitation paradigms. Show more

Keywords: Virtual environment, VR, motor control, imitation, hand

DOI: 10.3233/RNN-2009-0471

Citation: Restorative Neurology and Neuroscience, vol. 27, no. 3, pp. 209-223, 2009

Authors: Vogt, Annamarie | Kappos, Ludwig | Calabrese, Pasquale | Stöcklin, Markus | Gschwind, Leo | Opwis, Klaus | Penner, Iris-Katharina

Article Type: Research Article

Abstract: Purpose: Evaluation of two different training schedules of a computer based working memory training (BrainStim) in patients with multiple sclerosis (MS). Method: Forty-five MS outpatients were allocated to two different training groups and a control group without training. Patients with treatment received 16 training sessions scheduled either as a high intensity training (4 times per week for 4 weeks) or as a distributed training (2 times per week for 8 weeks). A neuropsychological test …battery including self-report measures was applied at baseline and at retest. The baseline assessment was performed twice at an interval of two weeks to control for possible learning effects. Results: In the outcome measures training for both intervention groups led to significantly improved fatigue symptoms as well as working memory -, and mental speed performances. Log files recorded during training showed a similar increase in levels of difficulty for both intervention groups as training progressed. No effects were found on short term memory, quality of life or depression. Conclusions: Since comparable improvements were observed in both training groups, BrainStim can be applied as a therapeutic intervention adjusted to the personal agenda of MS patients. Show more

Keywords: Multiple sclerosis, cognitive rehabilitation, working memory, computerized training, BrainStim

DOI: 10.3233/RNN-2009-0473

Citation: Restorative Neurology and Neuroscience, vol. 27, no. 3, pp. 225-235, 2009

Authors: Skouras, Emmanouil | Merkel, Daniel | Grosheva, Maria | Angelova, Srebrina K. | Schiffer, Gereon | Thelen, Ulrich | Kaidoglou, Katerina | Sinis, Nektarios | Igelmund, Peter | Dunlop, Sarah A. | Pavlov, Stoyan | Irintchev, Andrey | Angelov, Doychin N.

Article Type: Research Article

Abstract: The outcome of peripheral nerve injuries requiring surgical repair is poor. Recent work suggested that electrical stimulation (ES) of the proximal nerve stump to produce repeated discharges of the parent motoneurons for one hour could be a beneficial therapy if delivered immediately prior to reconstructive surgery of mixed peripheral nerves. Purpose: We tested whether ES has a positive influence on functional recovery after repair of a purely motor nerve, the facial nerve. …Methods: Electrical stimulation (20 Hz) was delivered to the proximal nerve stump of the transected facial nerve for 1 hour prior to nerve reconstruction by end-to-end suture (facial-facial anastomosis, FFA). For manual stimulation (MS), animals received daily rhythmic stroking of the whisker pads. Restoration of vibrissal motor performance following ES or MS was evaluated using video-based motion analysis. We also assessed the degree of collateral axonal branching at the lesion site, by counting motoneuronal perikarya after triple retrograde labeling, and estimated the quality of motor end-plate reinnervation in the target musculature. Outcomes at 4 months were compared to animals receiving sham stimulation (SS) or MS. Results: Neither protocol reduced the degree of collateral sprouting. ES did not improve functional outcome and failed to reduce the proportion of polyinnervated motor end-plates. By contrast, MS restored normal whisking function and reduced polyinnervation. Conclusion: Whereas acute ES is not beneficial for facial nerve repair, MS provides long-term benefits. Show more

Keywords: Electrical stimulation, facial nerve, functional recovery, motoneuron, nerve repair

DOI: 10.3233/RNN-2009-0474

Citation: Restorative Neurology and Neuroscience, vol. 27, no. 3, pp. 237-251, 2009