Restorative Neurology and Neuroscience - Volume 35, issue 4

Authors: Kantak, Shailesh | Jax, Steven | Wittenberg, George

Article Type: Research Article

Abstract: Inability to use the arm in daily actions significantly lowers quality of life after stroke. Most contemporary post-stroke arm rehabilitation strategies that aspire to re-engage the weaker arm in functional activities have been greatly limited in their effectiveness. Most actions of daily life engage the two arms in a highly coordinated manner. In contrast, most rehabilitation approaches predominantly focus on restitution of the impairments and unilateral practice of the weaker hand alone. We present a perspective that this misalignment between real world requirements and intervention strategies may limit the transfer of unimanual capability to spontaneous arm use and functional recovery. …We propose that if improving spontaneous engagement and use of the weaker arm in real life is the goal, arm rehabilitation research and treatment need to address the coordinated interaction between arms in targeted theory-guided interventions. Current narrow focus on unimanual deficits alone, difficulty in quantifying bimanual coordination in real-world actions and limited theory-guided focus on control and remediation of different coordination modes are some of the biggest obstacles to successful implementation of effective interventions to improve bimanual coordination in the real world. We present a theory-guided taxonomy of bimanual actions that will facilitate quantification of coordination for different real-world tasks and provide treatment targets for addressing coordination deficits. We then present evidence in the literature that points to bimanual coordination deficits in stroke survivors and demonstrate how current rehabilitation approaches are limited in their impact on bimanual coordination. Importantly, we suggest theory-based areas of future investigation that may assist quantification, identification of neural mechanisms and scientifically-based training/remediation approaches for bimanual coordination deficits post-stroke. Advancing the science and practice of arm rehabilitation to incorporate bimanual coordination will lead to a more complete functional recovery of the weaker arm, thus improving the effectiveness of rehabilitation interventions and augmenting quality of life after stroke. Show more

Keywords: Bimanual coordination, training, arm rehabilitation, stroke

DOI: 10.3233/RNN-170737

Citation: Restorative Neurology and Neuroscience, vol. 35, no. 4, pp. 347-364, 2017

Authors: Gao, Ying | Sabel, Bernhard A.

Article Type: Research Article

Abstract: Background: Besides the reduction of visual field size, hemianopic patients may also experience other poorly understood symptoms such as blurred vision, diplopia, or reduced visual acuity, which may be related to microsaccade function. Objective: To determine (i) if microsaccades are altered in hemianopia; (ii) how altered microsaccade features correlate with visual performances; and (iii) how their direction relates to visual field defect topography. Methods: In this case-control study, microsaccades of hemianopic stroke patients (n  = 14) were assessed with high-resolution eye-tracking technique, compared with those of healthy controls (n  = 14), and correlated with visual performances, visual field …defect parameters and lesion age. Results: Patients’ microsaccades had (i) larger amplitude (P  = 0.027), (ii) longer duration (P  = 0.042), and (iii) impaired binocular microsaccade conjugacy (horizontal: P  = 0.002; vertical: P  = 0.035). Older lesions were associated with poorer binocular conjugacy (horizontal: r(14) = 0.67, P  = 0.009; vertical: r(14) = 0.75, P  = 0.002) and larger microsaccade amplitudes (r(14) = 0.55, P  = 0.043). (iv) Half of the patients had a microsaccade bias towards the seeing field (monocular: P  = 0.002; binocular: P  < 0.001) which was associated with faster reactions to super-threshold visual stimuli in areas of residual vision (P  = 0.042). Finally, (v) patients with more binocular microsaccades (r(14) = 0.59, P  = 0.027) and lower microsaccade velocity (r(14) = –0.66, P  = 0.011) had better visual acuity. Conclusions: Hemianopia leads not only to the loss of visual field but also to microsaccade enlargement and impaired binocular conjugacy, suggesting malfunctioning microsaccade control circuits which worsen over time. But a microsaccade bias towards the seeing field, which suggests greater allocation of attention, accelerates stimulus detection. Microsaccades may play a role to compensate for vision impairment and provide a basis for vision restoration and plasticity, which deserves further exploration. Show more

Keywords: Microsaccade, binocular conjugacy, hemianopia, stroke, quality of life, stroke, visual field, vision restoration

DOI: 10.3233/RNN-170749

Citation: Restorative Neurology and Neuroscience, vol. 35, no. 4, pp. 365-376, 2017

Authors: Leon, Daniel | Cortes, Mar | Elder, Jessica | Kumru, Hatice | Laxe, Sara | Edwards, Dylan James | Tormos, Josep Maria | Bernabeu, Montserrat | Pascual-leone, Alvaro

Article Type: Research Article

Abstract: Background: Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique, which can modulate cortical excitability and combined with rehabilitation therapies may improve motor recovery after stroke. Objective: Our aim was to study the feasibility of a 4-week robotic gait training protocol combined with tDCS, and to study tDCS to the leg versus hand motor cortex or sham to improve walking ability in patients after a subacute stroke. Methods: Forty-nine subacute stroke patients underwent 20 daily sessions (5 days a week for 4 weeks) of robotic gait training combined with tDCS. Patients were assigned either …to the tDCSleg group (n  = 9), receiving 2 mA anodal tDCS over the motor cortex leg representation (vertex), or an active control group (n  = 17) receiving anodal tDCS over the hand motor cortex area (tDCShand ). In addition, we studied 23 matched patients in a control group receiving gait training without tDCS (no tDCS). Study outcomes included gait speed (10-meter walking test), and quality of gait, using the Functional Ambulatory Category (FAC) before and after the 4-week training period. Results: Only one patient did not complete the treatment because he presented a minor side-effect. Patients in all three groups showed a significantly improvement in gait speed and FAC. The tDCSleg group did not perform better than the tDCShand or no tDCS group. Conclusion: Combined tDCS and robotic training is a safe and feasible procedure in subacute stroke patients. However, adding tDCS to robot-assisted gait training shows no benefit over robotic gait training alone. Show more

Keywords: Robot-assisted gait training, subacute stroke, transcranial direct current stimulation

DOI: 10.3233/RNN-170734

Citation: Restorative Neurology and Neuroscience, vol. 35, no. 4, pp. 377-384, 2017

Authors: Ebrahimi-Monfared, Mohsen | Sharafkhah, Mojtaba | Abdolrazaghnejad, Ali | Mohammadbeigi, Abolfazl | Faraji, Fardin

Article Type: Research Article

Abstract: Background: Melatonin is known to be effective in curing migraine. Objective: This study aimed to investigate the therapeutic effect of melatonin versus sodium valproate in the prophylaxis of chronic migraine. Methods: This randomized, double-blind, placebo-controlled clinical trial included patients with chronic migraine who were divided into three equal sized groups, and baseline therapy with nortriptyline (10–25 mg) and propranolol (20–40 mg) was used. Patients in groups A, B, and C were adjunctively treated daily with 3 mg melatonin, 200 mg sodium valproate, and a placebo, respectively. The patients underwent treatment for 2 months and follow-up was done at baseline (baseline …), first (I ) and second month (II ). Attack frequency (AF), attack duration, attack severity, Migraine Disability Assessment (MIDAS) score (within 3 months in two steps), analgesic intake, and drug side effects between the groups and during follow-up were compared. Results: The mean of monthly AF (melatonin: baseline: 4.2, I: 3.1, II: 2.5, p  = 0.018; valproate: baseline: 4.3, I: 3.1, II: 2.3, p  = 0.001; placebo: baseline: 4.1, I: 3.8, II: 3.8 p  = 0.211), attack duration (hr) (melatonin: baseline: 19.8, I: 10.1, II: 8.7, p  < 0.001; valproate: baseline: 19.5, I: 10.2, II: 8.8, p  < 0.001; placebo: baseline: 19.6, I: 15.4, II: 14.1, p  = 0.271), attack severity (melatonin: baseline: 7.3, I: 5.4, II: 3.5, p  < 0.001; valproate: baseline: 7.4, I: 5.3, II: 3.4, p  = 0.000; placebo: baseline: 7.3, I: 6.4, II: 6, p  = 0.321), and MIDAS score (melatonin: baseline: 15.2, II: 8.9, p  = 0.005; valproate: baseline: 16.1, II: 8.3, p  = 0.001; placebo: baseline: 16, II: 12.1, p  = 0.44), were significantly reduced in the melatonin and sodium valproate groups, but not in the placebo groups. Adverse events were reported in 11 patients (10.47%): 2 (5.71%) during melatonin treatment, 8 (22.85%) during valproate, and 1 (2.85%) during placebo. Conclusion: The adjuvant treatment with melatonin was found to be superior to the placebo and had the same clinical efficacy as sodium valproate, but with higher tolerability. Melatonin may prove to be an efficient substitute for sodium valproate, as a chronic migraine prophylaxis. Show more

Keywords: Migraine disorders, melatonin, valproic acid

DOI: 10.3233/RNN-160704

Citation: Restorative Neurology and Neuroscience, vol. 35, no. 4, pp. 385-393, 2017

Authors: Stewart, Andrew Nathaniel | Matyas, Jessica Jane | Welchko, Ryan Matthew | Goldsmith, Alison Delanie | Zeiler, Sarah Elizabeth | Hochgeschwender, Ute | Lu, Ming | Nan, Zhenhong | Rossignol, Julien | Dunbar, Gary Leo

Article Type: Research Article

Abstract: Purpose: Utilizing genetic overexpression of trophic molecules in cell populations has been a promising strategy to develop cell replacement therapies for spinal cord injury (SCI). Over-expressing the chemokine, stromal derived factor-1 (SDF-1α), which has chemotactic effects on many cells of the nervous system, offers a promising strategy to promote axonal regrowth following SCI. The purpose of this study was to explore the effects of human SDF-1α, when overexpressed by mesenchymal stem cells (MSCs), on axonal growth and motor behavior in a contusive rat model of SCI. Methods: Using a transwell migration assay, the paracrine effects of MSCs, which …were engineered to secrete human SDF-1α (SDF-1-MSCs), were assessed on cultured neural stem cells (NSCs). For in vivo analyses, the SDF-1-MSCs, unaltered MSCs, or Hanks Buffered Saline Solution (vehicle) were injected into the lesion epicenter of rats at 9-days post-SCI. Behavior was analyzed for 7-weeks post-injury, using the Basso, Beattie, and Bresnahan (BBB) scale of locomotor functions. Immunohistochemistry was performed to evaluate major histopathological outcomes, including gliosis, inflammation, white matter sparing, and cavitation. New axonal outgrowth was characterized using immunohistochemistry against the neuron specific growth-associated protein-43 (GAP-43). Results: The results of these experiments demonstrate that the overexpression of SDF-1α by MSCs can enhance the migration of NSCs in vitro . Although only modest functional improvements were observed following transplantation of SDF-1-MSCs, a significant reduction in cavitation surrounding the lesion, and an increased density of GAP-43-positive axons inside the SCI lesion/graft site were found. Conclusion: The results from these experiments support the potential role for utilizing SDF-1α as a treatment for enhancing growth and regeneration of axons after traumatic SCI. Show more

Keywords: Spinal cord injury, stromal derived factor-1, CXCL12, GAP-43, mesenchymal stem cell

DOI: 10.3233/RNN-160678

Citation: Restorative Neurology and Neuroscience, vol. 35, no. 4, pp. 395-411, 2017

Authors: Schoemann, Micha Daniel | Lochmann, Matthias | Paulus, Jan | Michelson, Georg

Article Type: Research Article

Abstract: Background: Current studies revealed the importance of perceptual training for the treatment of amblyopia. To improve stereo vision on a higher level, visual tasks have to be completed within a limited time window like in repetitive visual function tests. “Processing time” as the reaction time in which the absence or presence of depth was identified correctly, is of better predictive value for perceiving the depth than the stereo threshold only. Objective: To examine the long-term effects of repetitive dynamic testing of stereopsis on processing time. Methods: 15 male soccer athletes (13.3±3.2 years) underwent twelve sessions of …a 15 minutes repetitive dynamic stereovision training over a period of six weeks, presented on a polarized 3D-TV in a four-alternative forced choice setup. We measured the response time of correct identified visual tasks of 11, 22, 44, 55, 66, 77 and 88arcsecs disparity before, after six sessions, after twelve sessions and after six month without testing. As response time is the sum of stereo processing time plus the motor reaction time, we defined the difference between the response times at 11 and 88arcsecs as “stereo processing time at 11arcsecs”. A Wilcoxon Signed Rank Test was conducted between the testing sessions to evaluate significant changes in response time and stereo processing time. Results: After six sessions the mean stereo processing time at 11arcsecs decreased significantly from 804.4 ms to 403.7 ms (Z  = –2.499, p  = 0.012). Six months after the last training the stereo processing time at 11arcsecs remained at the level of the last session. Conclusion: Our results suggest that repetitive testing of stereovision is effective in improving processing time of stereoscopic tasks in young male athletes significantly long-term. Show more

Keywords: Binocular vision, depth perception, detection/discrimination, depth, learning, plasticity, stereopsis, stereo acuity

DOI: 10.3233/RNN-170729

Citation: Restorative Neurology and Neuroscience, vol. 35, no. 4, pp. 413-421, 2017

Authors: Aravind, Gayatri | Lamontagne, Anouk

Article Type: Research Article

Abstract: Background: Persons with perceptual-attentional deficits due to visuospatial neglect (VSN) after a stroke are at a risk of collisions while walking in the presence of moving obstacles. The attentional burden of performing a dual-task may further compromise their obstacle avoidance performance, putting them at a greater risk of collisions. Objective: The objective of this study was to compare the ability of persons with (VSN+) and without VSN (VSN–) to dual task while negotiating moving obstacles. Methods: Twenty-six stroke survivors (13 VSN+, 13 VSN–) were assessed on their ability to (a) negotiate moving obstacles while walking (locomotor …single task); (b) perform a pitch-discrimination task (cognitive single task) and (c) simultaneously perform the walking and cognitive tasks (dual task). We compared the groups on locomotor (collision rates, minimum distance from obstacle and onset of strategies) and cognitive (error rates) outcomes. Results: For both single and dual task walking, VSN+ individuals showed higher collision rates compared to VSN– individuals. Dual tasking caused deterioration of locomotor (more collisions, delayed onset and smaller minimum distances) and cognitive performances (higher error rate) in VSN+ individuals. Contrastingly, VSN– individuals maintained collision rates, increased minimum distance, but showed more cognitive errors, prioritizing their locomotor performance. Conclusion: Individuals with VSN demonstrate cognitive-locomotor interference under dual task conditions, which could severely compromise safety when ambulating in community environments and may explain the poor recovery of independent community ambulation in these individuals. Show more

Keywords: Circumvention, dual tasking, hemineglect, locomotion, virtual reality

DOI: 10.3233/RNN-160709

Citation: Restorative Neurology and Neuroscience, vol. 35, no. 4, pp. 423-436, 2017