Restorative Neurology and Neuroscience - Volume 29, issue 5

Authors: da Silva Cameirão, Mónica | Bermúdez i Badia, Sergi | Duarte, Esther | Verschure, Paul F.M.J.

Article Type: Research Article

Abstract: Purpose: Given the incidence of stroke, the need has arisen to consider more self-managed rehabilitation approaches. A promising technology is Virtual Reality (VR). Thus far, however, it is not clear what the benefits of VR systems are when compared to conventional methods. Here we investigated the clinical impact of one such system, the Rehabilitation Gaming System (RGS), on the recovery time course of acute stroke. RGS combines concepts of action execution and observation with an automatic individualization of training. Methods. Acute stroke patients (n = 8) used the RGS during 12 weeks in addition to conventional therapy. A control group …(n = 8) performed a time matched alternative treatment, which consisted of intense occupational therapy or non-specific interactive games. Results. At the end of the treatment, between-group comparisons showed that the RGS group displayed significantly improved performance in paretic arm speed that was matched by better performance in the arm subpart of the Fugl-Meyer Assessment Test and the Chedoke Arm and Hand Activity Inventory. In addition, the RGS group presented a significantly faster improvement over time for all the clinical scales during the treatment period. Conclusions. Our results suggest that rehabilitation with the RGS facilitates the functional recovery of the upper extremities and that this system is therefore a promising tool for stroke neurorehabilitation. Show more

Keywords: Acute stroke, rehabilitation, mirror neurons, virtual reality, Rehabilitation Gaming Station

DOI: 10.3233/RNN-2011-0599

Citation: Restorative Neurology and Neuroscience, vol. 29, no. 5, pp. 287-298, 2011

Authors: Rijntjes, Michel | Hamzei, Farsin | Glauche, Volkmar | Saur, Dorothee | Weiller, Cornelius

Article Type: Research Article

Abstract: Purpose: The integrity of the pyramidal tract (PT) does not seem to influence clinical improvement after two weeks of Constraint-Induced Movement Therapy (CIMT). However, when PT is intact, improvement is associated with a decrease of fMRI-activation in primary sensorimotor cortex (SMC) and when affected, with an increase of activation in SMC. The aim was to observe the long-term effect of CIMT, depending on the integrity of the PT, and to correlate improvement with changes in fMRI-activation. Subjects and methods: Twelve new chronic stroke patients were treated with CIMT and integrity of PT was measured with transcranial magnetic stimulation. Before therapy, …after therapy, and after 6 months, changes in motor function were correlated with differential and percent fMRI signal changes. Results: All patients improved after two weeks of therapy, but only those with intact PT maintained improvement after 6 months. When PT was intact, improvement correlated with first a decrease of activation in SMC and after 6 months with an increase. When PT was affected, improvement consistently correlated with an increase in a lateral extension of SMC. Percent changes of activation were surrounded by differential changes. Conclusions: An intact PT might be advantageous for lasting improvement after CIMT and subregions in the SMC seem to behave differently during recovery. Show more

Keywords: Motor stroke, recovery, fMRI, CIMT

DOI: 10.3233/RNN-2011-0600

Citation: Restorative Neurology and Neuroscience, vol. 29, no. 5, pp. 299-310, 2011

Authors: Thirugnanasambandam, Nivethida | Sparing, Roland | Dafotakis, Manuel | Meister, Ingo G. | Paulus, Walter | Nitsche, Michael A. | Fink, Gereon R.

Article Type: Research Article

Abstract: Background and Purpose: Neuroplastic alterations of cortical excitability and activity represent the likely neurophysiological foundation of learning and memory formation. Beyond their induction, alterations of these processes by subsequent modification of cortical activity, termed metaplasticity, came into the focus of interest recently. Animal slice experiments demonstrated that neuroplastic excitability enhancements, or diminutions, can be abolished by consecutive subthreshold stimulation. These processes, termed de-potentiation, and de-depression, have so far not been explored in humans. Methods: We combined neuroplasticity induction by transcranial direct current stimulation (tDCS) applied to the hand area of primary motor cortex (M1), which can be used to induce …long-lasting excitability enhancements or reductions, dependent on the polarity of stimulation, with short-lasting voluntary muscle contraction (VMC), which itself does not induce plastic cortical excitability changes. Corticospinal and intra-cortical M1 excitability were monitored by different transcranial magnetic stimulation (TMS) protocols. Results: VMC reduced or tended to reverse the anodal tDCS-driven motor cortical excitability enhancement and the cathodal tDCS-induced excitability diminution. Our findings thus demonstrate de-potentiation- and de-depression-like phenomena at the system level in the human motor cortex. Conclusion: This neurophysiological study may contribute to a better understanding of the balance between induction and reversal of plasticity associated with motor learning and rehabilitation processes. Show more

Keywords: Transcranial direct current stimulation (tDCS), transcranial magnetic stimulation (TMS), voluntary muscle contraction, de-potentiation, de-depression

DOI: 10.3233/RNN-2011-0601

Citation: Restorative Neurology and Neuroscience, vol. 29, no. 5, pp. 311-320, 2011

Authors: Luukkainen-Markkula, R. | Tarkka, I.M. | Pitkänen, K. | Sivenius, J. | Hämäläinen, H.

Article Type: Research Article

Abstract: Purpose: Recent studies of hemispatial neglect have revealed both lateralized and nonlateralized attention mechanisms contributing to the syndrome. In addition, neglect patients show impaired spatial working memory and diminished working memory capacity. The aim of this study was to investigate, how neglect would be reflected in their performances in commonly used clinical visual memory tests. Methods: Twelve patients with right hemisphere lesions and left neglect and twelve matched controls were assessed with the Behavioural Inattention Test, the visual reproduction of the WMS-R, the object memory test, the Rey figure test and the list learning test. Visuo-spatial span was explored with …the Corsi block test. Results: The severity of neglect was significantly associated with the naming of objects from the left side, with the copying of the Rey figure and with the immediate visual reproduction of the WMS-R. In comparison to the matched controls, the patients named and copied fewer items from both sides and showed impaired immediate and delayed recall of visual material, more so from the left side. After recovery, patients were still impaired in their visual search, whereas their immediate reproduction of visual material was no longer significantly different from the control subjects. The deficit in delayed recall of visual material persisted and was lateralized to the left side of the recollected memories. The role of hemianopia was analyzed. Conclusions: Patients with neglect exhibited spatial working memory bias and diminished nonlateralized attention capacity in encoding and immediate recall. The deficit in delayed recall was lateralized to the left side of memorized material. Show more

Keywords: Right hemisphere stroke, recovery after stroke, neuropsychological examination, hemispatial neglect, representational neglect, visual memory, spatial working memory

DOI: 10.3233/RNN-2011-0602

Citation: Restorative Neurology and Neuroscience, vol. 29, no. 5, pp. 321-330, 2011

Authors: Beller, Justin A. | Gurkoff, Gene G. | Berman, Robert F. | Lyeth, Bruce G.

Article Type: Research Article

Abstract: Purpose: Glutamate transporters are responsible for removing glutamate from the extracellular space and have the potential to protect neurons from excitotoxicity. In the present study, the effects of ceftriaxone and (2R, 4R)-APDC (APDC) on the protein expression of GLAST and GLT-1, the rate of glutamate uptake, and neuroprotection were evaluated in a cell culture model of glutamate excitotoxicity. Methods: Mixed neuron/astrocyte cultures were prepared from 1 day old rat pups. Protein levels of GLAST and GLT-1 glutamate transporters were quantified using In-Cell Western techniques after acute or 5-day treatment with either ceftriaxone or APDC. Glutamate uptake was measured using Michaelis-Menten …kinetics to evaluate the effects of 5-day treatment with ceftriaxone or APDC. Neuronal cell death in response to a 10-minute 1 mM glutamate challenge was measured following 5-day treatment with either ceftriaxone or APDC. Results: Five-day treatment with 100 μM ceftriaxone significantly increased both GLAST and GLT-1 protein levels 31.3% and 47.5% above control, respectively, increased the Vmax 29.3%, increased the Km of glutamate uptake 117.9%, and reduced neuronal death 22.0% after a 1 mM glutamate challenge. Five-day treatment with 1 mM APDC significantly increased GLAST protein levels 27.6%, increased the Vmax 92.4%, increased the Km of glutamate transport 118.9%, and decreased neuronal death 36.8% after a 1 mM glutamate challenge. Conclusions: Chronic treatment with ceftriaxone or APDC provided neuroprotection from glutamate excitotoxicity while increasing GLAST and GLT-1 protein levels and increasing glutamate uptake. These compounds may have therapeutic potential in chronic excitotoxic neurodegenerative diseases. Show more

Keywords: Pharmacology, neurodegeneration, ceftriaxone, group II mGluR

DOI: 10.3233/RNN-2011-603

Citation: Restorative Neurology and Neuroscience, vol. 29, no. 5, pp. 331-346, 2011

Authors: Bergsma, D.P. | Leenders, M.J.A. | Verster, J.C. | van der Wildt, G.J. | van den Berg, A.V.

Article Type: Research Article

Abstract: Background: Visual Restorative function training aims to decrease visual field defect size after acquired brain damage. Some chronic stroke patients regain permission to drive a car after training. This points to a concomitant change in oculomotor behavior, because visual field enlargement is hardly ever large enough for legal driving. This study investigated vRFT-induced changes in oculomotor behavior, using a driving simulator. Methods: Driving performance and oculomotor behavior were measured before and after training in 6 hemianopia patients who had trained 65 hours with vRFT on a PC at home. Results: Two patients showed negligible visual field enlargement (VFE) and four …showed moderate to substantial VFE. Because less visual cortex is devoted to the processing of peripheral than central visual field the same VFE corresponds to less functional restoration of cortex when the defect is at high eccentricity. When this is taken into account, then precisely the two patients that showed the largest cortical gains made significantly more eye movements in the direction of their visual field defect after training. Conclusions: vRFT with mandatory eye fixation can result in increased eye movement behavior towards the defect. Our study suggests that a threshold amount of cortical functional restoration is required for this effect. Show more

Keywords: Stroke, homonymous hemianopia, restorative function training, visual field enlargement, driving simulator, attention

DOI: 10.3233/RNN-2011-604

Citation: Restorative Neurology and Neuroscience, vol. 29, no. 5, pp. 347-359, 2011