Restorative Neurology and Neuroscience - Volume 34, issue 1

Authors: Gram, Marie Gajhede | Wogensen, Elise | Wörtwein, Gitta | Mogensen, Jesper | Malá, Hana

Article Type: Research Article

Abstract: Purpose: To i) evaluate the effect of a restraint procedure (7 days, 2 h/day) on place learning after fimbria-fornix transection (FF), ii) investigate effects of early vs. late administration of restraint, and iii) establish effects of the restraint procedure on expression of brain derived neurotrophic factor (BDNF) in prefrontal cortex and hippocampus. Methods: Fifty rats subjected to FF or sham surgery and divided into groups exposed to restraint immediately (early restraint) or 21 days (late restraint) after surgery were trained to acquire an allocentric place learning task. In parallel, 29 animals were subjected to FF or sham surgery and …an identical restraint procedure in order to measure concentrations of BDNF and corticosterone. Results: The performance of the sham operated rats was positively affected by the late restraint. In FF-lesioned animals, the late restraint significantly improved task performance compared to the lesioned group with no restraint, while the early restraint was associated with a negative impact on task acquisition. Biochemical analysis after restraint procedure revealed a lesion-induced upregulation of BDNF in FF animals. Conclusions: The improved task performance of lesioned animals suggests a therapeutic effect of this manipulation, independent of BDNF. This effect is sensitive to the temporal administration of treatment. Show more

Keywords: Brain injury, restraint procedure, rat, functional recovery, time

DOI: 10.3233/RNN-140396

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 1-17, 2016

Authors: Gleichgerrcht, Ezequiel | Kocher, Madison | Nesland, Travis | Rorden, Chris | Fridriksson, Julius | Bonilha, Leonardo

Article Type: Research Article

Abstract: Purpose: Post-stroke aphasia is typically associated with ischemic damage to cortical areas or with loss of connectivity among spared brain regions. It remains unclear whether the participation of spared brain regions as networks hubs affects the severity of aphasia. Methods: We evaluated language performance and magnetic resonance imaging from 44 participants with chronic aphasia post-stroke. The individual structural brain connectomes were constructed from diffusion tensor. Hub regions were defined in accordance with the rich club classification and studied in relation with language performance. Results: Number of remaining left hemisphere rich club nodes was associated with aphasia, …including comprehension, repetition and naming sub-scores. Importantly, among participants with relative preservation of regions of interest for language, aphasia severity was lessened if the region was not only spared, but also participated in the remaining network as a rich club node: Brodmann area (BA) 44/45 - repetition (p  = 0.009), BA 39 - repetition (p  = 0.045) and naming (p  <  0.01), BA 37 - fluency (p  <  0.001), comprehension (p  = 0.025), repetition (p  <  0.001) and naming (p  <  0.001). Conclusions: Disruption of language network structural hubs is directly associated with aphasia severity after stroke. Show more

Keywords: Connectome, magnetic resonance imaging, diffusion tensor imaging, structural networks, hubs, rich club, aphasia, stroke, language performance

DOI: 10.3233/RNN-150511

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 19-28, 2016

Authors: Proulx, Michael J. | Gwinnutt, James | Dell’Erba, Sara | Levy-Tzedek, Shelly | de Sousa, Alexandra A. | Brown, David J.

Article Type: Research Article

Abstract: Vision is the dominant sense for perception-for-action in humans and other higher primates. Advances in sight restoration now utilize the other intact senses to provide information that is normally sensed visually through sensory substitution to replace missing visual information. Sensory substitution devices translate visual information from a sensor, such as a camera or ultrasound device, into a format that the auditory or tactile systems can detect and process, so the visually impaired can see through hearing or touch. Online control of action is essential for many daily tasks such as pointing, grasping and navigating, and adapting to a sensory substitution …device successfully requires extensive learning. Here we review the research on sensory substitution for vision restoration in the context of providing the means of online control for action in the blind or blindfolded. It appears that the use of sensory substitution devices utilizes the neural visual system; this suggests the hypothesis that sensory substitution draws on the same underlying mechanisms as unimpaired visual control of action. Here we review the current state of the art for sensory substitution approaches to object recognition, localization, and navigation, and the potential these approaches have for revealing a metamodal behavioral and neural basis for the online control of action. Show more

Keywords: Sensory substitution, blindness, prosthetics, object recognition, perception for action, active sensing

DOI: 10.3233/RNN-150541

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 29-44, 2016

Authors: Simis, Marcel | Doruk, Deniz | Imamura, Marta | Anghinah, Renato | Morales-Quezada, Leon | Fregni, Felipe | Battistella, Linamara Rizzo

Article Type: Research Article

Abstract: Purpose: Understanding the neural mechanisms of stroke recovery is of paramount importance for neurorehabilitation. Methods: For this purpose, we analyzed several TMS and EEG variables and their association with motor recovery. Thirty-five subjects with chronic stroke were recruited. The neurophysiological examination included assessments by transcranial magnetic stimulation (TMS), intra- and inter-hemispheric EEG coherence in different frequency bands (e.g. alpha (8–13 Hz)) as determined by quantitative electroencephalography (qEEG). Motor function was measured by Fugl-Meyer (FM). Multiple univariate and multivariate linear regression analyses were performed to identify the predictors for FM. Results: Multivariate analyses, showed a significant interaction effect …of motor threshold (MT) in the lesioned hemisphere and beta coherence in the unlesioned hemisphere. This interaction suggests that higher beta activity in the unlesioned hemisphere strengthens the negative association between MT and FM scores. Conclusions: Our results suggest that MT in the lesioned hemisphere is the strongest predictors of motor recovery after stroke. Moreover, cortical activity in the unlesioned hemisphere measured by qEEG provides additional information, specifying the association between MT and FM scores. Therefore, complementary application of EEG and TMS can help constitute a better model of the lesioned and the unlesioned hemispheres that supports the importance of bihemispheric activity in recovery. Show more

Keywords: Stroke, cerebrovascular disease, cortical excitability, plasticity, transcranial magnetic stimulation (TMS), quantitative electroencephalography (qEEG), motor recovery

DOI: 10.3233/RNN-150550

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 45-54, 2016

Authors: Cheng, F.P.-H. | Eddy, M.-L. | Ruiz, M. Herrojo | Großbach, M. | Altenmüller, E.O.

Article Type: Research Article

Abstract: Purpose: Musician’s dystonia (MD) is a task-specific movement disorder related to extensive expert music performance training. Similar to other forms of focal dystonia, MD involves sensory deficits and abnormal patterns of sensorimotor integration. The present study investigated the impaired cortical sensorimotor network of pianists who suffer from MD by employing altered auditory and tactile feedback during scale playing with multichannel EEG. Methods: 9 healthy professional pianists and 9 professional pianists suffering from right hand MD participated in an experiment that required repeated scale playing on a MIDI piano under altered sensory feedback while EEG was measured. …Results: The comparison of EEG data in healthy pianists and pianists suffering from MD revealed a higher degree of inter-regional phase synchronisation between the frontal and parietal regions and between the temporal and central regions in the patient group and in conditions that are relevant to the long-trained auditory-motor coupling (normal auditory feedback and complete deprivation of auditory feedback), but such abnormalities decreased in conditions with delayed auditory feedback and altered tactile feedback. Conclusions: These findings support the hypothesis that the impaired sensorimotor integration of MD patients is specific to the type of overtrained task that the patients were trained for and can be modified with altered sensory feedback. Show more

Keywords: Pianist, EEG, altered auditory feedback, phase synchronisation, sensorimotor integration

DOI: 10.3233/RNN-150554

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 55-65, 2016

Authors: Clara, Casco | Elisa, DeStefani | Luisa, Pinello | Giovanni, Sato | Luca, Battaglini

Article Type: Research Article

Abstract: Purpose: This study aims at comparing participants with juvenile macular degeneration (MD) and normally sighted observers in their sensitivity to mirror and translational symmetry. Methods: We measured in 25 normal sighted and 9 MD participants sensitivity (d ’) to detect the symmetry of two dot patterns presented at the opposite sides of their central scotoma. Results: At a large dot patterns separation (13.3 deg), at which detection failed in normally sighted observers, MD patients had high sensitivity to mirror symmetry, whereas translational symmetry was undetected. Conclusions: The mirror-translational dissociation is not predicted by the …well-known phenomenon of shrinking the location of images surrounding the scotoma. Our results indicate higher capacity of MD with respect to normally sighted observers to organize mirror symmetric dot patterns far apart into a unique percept. Our results suggest that MD have acquired the capability to use information only present in mirror symmetry, i.e., the co-aligned position of the centre of low-frequency filters connecting symmetric dot pairs on opposite sides of the scotoma. This relevant functional change in vision of MD patients may find its explanation in a functionally acquired high-level cortical representation of visual input. Show more

Keywords: Mirror symmetry, translational symmetry, cortical reorganization, macular degeneration, scotoma

DOI: 10.3233/RNN-150562

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 67-77, 2016

Authors: Schmalfuß, L. | Rupp, R. | Tuga, M.R. | Kogut, A. | Hewitt, M. | Meincke, J. | Klinker, F. | Duttenhoefer, W. | Eck, U. | Mikut, R. | Reischl, M. | Liebetanz, D.

Article Type: Research Article

Abstract: Purpose: Providing mobility solutions for individuals with tetraplegia remains challenging. Existing control devices have shortcomings such as varying or poor signal quality or interference with communication. To overcome these limitations, we present a novel myoelectric auricular control system (ACS) based on bilateral activation of the posterior auricular muscles (PAMs). Methods: Ten able-bodied subjects and two individuals with tetraplegia practiced PAM activation over 4 days using visual feedback and software-based training for 1 h/day. Initially, half of these subjects were not able to voluntarily activate their PAMs. This ability was tested with regard to 8 parameters such as contraction rate, …lateralized activation, wheelchair speed and path length in a virtual obstacle course. In session 5, all subjects steered an electric wheelchair with the ACS. Results: Performance of all subjects in controlling their PAMs improved steadily over the training period. By day 5, all subjects successfully generated basic steering commands using the ACS in a powered wheelchair, and subjects with tetraplegia completed a complex real-world obstacle course. This study demonstrates that the ability to activate PAM on both sides together or unilaterally can be learned and used intuitively to steer a wheelchair. Conclusions: With the ACS we can exploit the untapped potential of the PAMs by assigning them a new, complex function. The inherent advantages of the ACS, such as not interfering with oral communication, robustness, stability over time and proportional and continuous signal generation, meet the specific needs of wheelchair users and render it a realistic alternative to currently available assistive technologies. Show more

DOI: 10.3233/RNN-150579

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 79-95, 2016

Authors: Buchs, Galit | Maidenbaum, Shachar | Levy-Tzedek, Shelly | Amedi, Amir

Article Type: Research Article

Abstract: Purpose: To visually perceive our surroundings we constantly move our eyes and focus on particular details, and then integrate them into a combined whole. Current visual rehabilitation methods, both invasive, like bionic-eyes and non-invasive, like Sensory Substitution Devices (SSDs), down-sample visual stimuli into low-resolution images. Zooming-in to sub-parts of the scene could potentially improve detail perception. Can congenitally blind individuals integrate a ‘visual’ scene when offered this information via different sensory modalities, such as audition? Can they integrate visual information –perceived in parts - into larger percepts despite never having had any visual experience? Methods: We explored these …questions using a zooming-in functionality embedded in the EyeMusic visual-to-auditory SSD. Eight blind participants were tasked with identifying cartoon faces by integrating their individual components recognized via the EyeMusic’s zooming mechanism. Results: After specialized training of just 6–10 hours, blind participants successfully and actively integrated facial features into cartooned identities in 79±18% of the trials in a highly significant manner, (chance level 10% ; rank-sum P  <  1.55E-04). Conclusions: These findings show that even users who lacked any previous visual experience whatsoever can indeed integrate this visual information with increased resolution. This potentially has important practical visual rehabilitation implications for both invasive and non-invasive methods. Show more

Keywords: Sensory substitution, vision rehabilitation, action-perception, motor control, active sensing

DOI: 10.3233/RNN-150592

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 97-105, 2016

Authors: Wójcik-Gryciuk, Anna | Skup, Małgorzata | Waleszczyk, Wioletta J.

Article Type: Research Article

Abstract: Glaucoma is a chronic optic neuropathy characterized by progressive damage to the optic nerve, death of retinal ganglion cells and ultimately visual field loss. It is one of the leading causes of irreversible loss of vision worldwide. The most important trigger of glaucomatous damage is elevated eye pressure, and the current standard approach in glaucoma therapy is reduction of intraocular pressure (IOP). However, despite the use of effective medications or surgical treatment leading to lowering of IOP, progression of glaucomatous changes and loss of vision among patients with glaucoma is common. Therefore, it is critical to prevent vision loss through …additional treatment. To implement such treatment(s), it is imperative to identify pathophysiological changes in glaucoma and develop therapeutic methods taking into account neuroprotection. Currently, there is no method of neuroprotection with long-term proven effectiveness in the treatment of glaucoma. Among the most promising molecules shown to protect the retina and optic nerve are neurotrophic factors. Thus, the current focus is on the development of safe and non-invasive methods for the long-term elevation of the intraocular level of neurotrophins through advanced gene therapy and topical eye treatment and on the search for selective agonists of neurotrophin receptors affording more efficient neuroprotection. Show more

Keywords: Neurodegeneration, visual pathway, visual cortex, retina, optic disc, neuroprotection, trophic factors, retinal ganglion cells

DOI: 10.3233/RNN-150599

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 107-123, 2016

Authors: Arcolin, Ilaria | Pisano, Fabrizio | Delconte, Carmen | Godi, Marco | Schieppati, Marco | Mezzani, Alessandro | Picco, Daniele | Grasso, Margherita | Nardone, Antonio

Article Type: Research Article

Abstract: Purpose: Cycle ergometer training improves gait in the elderly, but its effect in patients with Parkinson’s disease (PD) is not completely known. Methods: Twenty-nine PD inpatients were randomized to treadmill (n  = 13, PD-T) or cycle ergometer (n  = 16, PD-C) training for 3 weeks, 1 hour/day. Outcome measures were distance travelled during the 6-min walking test (6MWT), spatio-temporal variables of gait assessed by baropodometry, the Timed Up and Go (TUG) duration, the balance score through the Mini-BESTest, and the score of the Unified Parkinson’s Disease Rating Scale (UPDRS). Results: Sex, age, body mass index, disease duration, Hoehn-Yahr …staging, comorbidity and medication did not differ between groups. At end of training, ANCOVA showed significant improvement, of similar degree, in both groups for 6MWT, speed, step length and cadence of gait, TUG, Mini-BESTest and UPDRS. Conclusions: This pilot study shows that cycle ergometer training improves walking parameters and reduces clinical signs of PD, as much as treadmill training does. Gait velocity is accompanied by step lengthening, making the gait pattern close to that of healthy subjects. Cycle ergometer is a valid alternative to treadmill for improving gait in short term in patients with PD. Show more

Keywords: Parkinson’s Disease, aerobic exercise, treadmill, cycle ergometer, balance, gait

DOI: 10.3233/RNN-150506

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 125-138, 2016

Authors: Paiva, Sílvia | Magalhães, Rosana | Alves, Jorge | Sampaio, Adriana

Article Type: Research Article

Abstract: Numerous studies have been conducted discussing the importance and effectiveness of cognitive interventions for stroke-related cognitive impairments. Definite conclusions, however, are yet to be established. An extensive literature and database search was executed to summarize the existing evidence from high-quality randomized clinical trials on the effects of cognitive intervention and feasibility of this approach in stroke patients. Out of 507 identified studies, after thorough inspection, only three randomized clinical trials, with low risk of bias, met the established criteria and were included in the following meta-analysis. No significant effects of cognitive intervention in any of the analyzed outcomes were observed …with feasibility analyzes displaying high rates of completion and adherence. The following study suggests a lack of sufficient evidence to support or refute the efficacy of cognitive intervention in stroke patients. However, these results should be interpreted with caution. Additionally, serious efforts must be made to improve the quality of empirical studies in the field. In sum, the quality of methodological techniques in the field were inspected in hopes of contributing to further development of this therapeutic approach. Show more

Keywords: Stroke, cognitive impairment, cognitive intervention, efficacy, feasibility, systematic review, meta-analysis

DOI: 10.3233/RNN-150590

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 139-152, 2016

Authors: Backhaus, W. | Kempe, S. | Hummel, F.C.

Article Type: Research Article

Abstract: There is extensive evidence for positive effects of sleep on motor learning in young individuals; however, the effects of sleep on motor learning in people with stroke and in healthy older individuals are not well understood. The aim of this systematic review was to quantify the association between sleep and procedural memory performance - a marker for motor learning - in healthy older people and people with stroke. After searches in PubMed, Medline and Embase fourteen studies, including 44 subjects after stroke and 339 healthy older participants were included. Overall, sleep was found to enhance motor performance in people after …stroke in comparison to an equivalent time of wakefulness. In addition, although evidence is limited, sleep only enhanced motor performance in people after stroke and not in age-matched healthy older adults. In older adults the effect of a sleep intervention did – in general - not differ from equivalent periods of wakefulness. Tasks with whole hand or whole body movements could show significant changes. The results suggest a delayed retention effect after longer breaks including sleep, hinting towards a changed learning strategy as a result of aging. Current evidence for sleep dependent learning in people after stroke is promising, however sparse. Show more

Keywords: Sleep, aging, stroke, motor memory, consolidation, systematic review

DOI: 10.3233/RNN-150521

Citation: Restorative Neurology and Neuroscience, vol. 34, no. 1, pp. 153-164, 2016