Restorative Neurology and Neuroscience - Volume 31, issue 6

Authors: Bola, Michał | Prilloff, Sylvia | Matzke, Steffi | Henrich-Noack, Petra

Article Type: Other

Abstract: Restoration of brain function was long thought to be impossible. However, as the publications in the journal Restorative Neurology and Neuroscience (RNN) for more than 20 years attest, clinically useful improvement can be achieved after damage or diseases of the brain, the retina, and the peripheral nervous system. By reviewing both pre-clinical studies and clinical work, we explore what advancements can be made today and what to expect going forward. For example, in the last few years we have seen a clinical focus in the area of non-invasive brain stimulations and rehabilitation training trials. In basic animal research multi-modal approaches …have been presented to restore brain function with a combination of different treatments. We think that this is an exciting time in the area of restoration of brain function with many new strategies aimed at helping recovering their impaired neurological functions. Show more

Keywords: Brain plasticity, neural repair, restoration, nervous system

DOI: 10.3233/RNN-139020

Citation: Restorative Neurology and Neuroscience, vol. 31, no. 6, pp. 669-679, 2013

Authors: Singer, Barbara J. | Vallence, Ann-Maree | Cleary, Sarah | Cooper, Ian | Loftus, Andrea M.

Article Type: Research Article

Abstract: Purpose: We examined the feasibility and outcome of electromyographically triggered electrical muscle stimulation (EMG-ES) plus unilateral or bilateral task specific practice on arm function in chronic stroke survivors with moderate-severe hemiplegia. Transcranial magnetic stimulation was used to examine inter-hemispheric inhibition (IHI) acting on the stroke-affected hemisphere in a subset of eight participants. Methods: Twenty-one stroke survivors (14 males; mean time post stroke 57.9 months) participated in this pilot investigation. Participants underwent a six-week program of daily EMG-ES training with random assignment to concurrent task practice using the stroke-affected hand only or both hands. The upper-extremity subscale of the Fugl-Meyer (FMUE) …and the Arm Motor Ability Test (AMAT) were completed at baseline, 0-, 1-, and 3-months post-intervention. Results: Following the intervention, FMUE (F(3, 57) = 3.89, p = .01, ηp2 = .17) and AMAT (F(3, 57) = 12.6, p = .01, ηp2 = .39) scores improved, and remained better than baseline at three months re-assessment. The difference between groups was not significant. A non-significant decrease in IHI was observed post-intervention. Conclusions: An intensive program of EMG-ES assisted functional training is feasible, well tolerated, and leads to improvements in moderate-severe deficits of arm function post stroke. Larger placebo controlled studies are needed to explore any advantage of bilateral over unilateral EMG-ES assisted training. Show more

Keywords: Stroke, upper limb, bilateral training, electrical stimulation, interhemispheric inhibition

DOI: 10.3233/RNN-130319

Citation: Restorative Neurology and Neuroscience, vol. 31, no. 6, pp. 681-691, 2013

Authors: Edwards, Jodi D. | Meehan, Sean K. | Linsdell, Meghan A. | Borich, Michael R. | Anbarani, Keivan | Jones, Paul W. | Ferris, Jennifer | Boyd, Lara A.

Article Type: Research Article

Abstract: Purpose: The purpose of the present study was to assess changes in thresholds for the onset of short intracortical inhibition (SICI) and intracortical facilitation (ICF) in individuals with chronic stroke compared to age-matched healthy adults and evaluate the relationship between these thresholds and motor function in the chronic stroke group. Methods: Paired-pulse transcranial magnetic stimulation was used to derive thresholds for the onset of SICI and ICF in 12 neurologically healthy and 12 individuals with chronic stroke. Motor evoked potentials were elicited by a test stimulus of fixed intensity preceded by a conditioning stimulus ranging from 0%–125% of active motor …threshold to generate recruitment curves. Regression functions were fit to these recruitment curves to identify thresholds for the onset of SICI and ICF. Mixed measures analysis of variance was used to compare thresholds for each hemisphere within and between groups. Results: Results showed a significant three-way interaction between Group (stroke, healthy), Hemisphere (ipsilesional, contralesional) and Stimulus interval (2 ms, 12 ms). Significant differences in the thresholds for the onset of both SICI and ICF were present in individuals with chronic stroke, with no between hemisphere differences for the control group. When compared to age-matched controls, comparisons revealed significant reductions in ipsilesional, but not contralesional thresholds for the onset of ICF, and significant reductions in contralesional, but not ipsilesional, thresholds for the onset of SICI in individuals with chronic stroke. In addition, as thresholds for ICF and SICI in stroke patients approached the level of healthy adults, higher function on the Wolf Motor Function Test was observed. Conclusions: Reduced thresholds for the onset of SICI and ICF observed in the present study indicate that both inhibitory and facilitatory systems mediate changes in cortical excitability in chronic stroke patients. The association between higher onset thresholds and motor function in the stroke group also suggests that these thresholds have potential utility for tracking functional motor improvements in patients with chronic stroke. This study provides new insights to further characterize changes in intracortical neurotransmission that play an important role in modulating neuroplasticity and the potential relationship between inhibitory and facilitatory networks and motor function post-stroke. Show more

Keywords: Intracortical inhibition, intracortical facilitation, transcranial magnetic stimulation, chronic stroke

DOI: 10.3233/RNN-120300

Citation: Restorative Neurology and Neuroscience, vol. 31, no. 6, pp. 693-705, 2013

Authors: Buma, Floor | Kwakkel, Gert | Ramsey, Nick

Article Type: Review Article

Abstract: This review addresses what is currently known about the time course of skill reacquisition after stroke. There is growing evidence that the natural logarithmic pattern of functional recovery can be modified by intensive task-oriented practice preferably initiated within 6 months after stroke. However, the impact of practice on the learning-dependent and intrinsic spontaneous mechanisms of neurological recovery is poorly understood. At least four probably interrelated mechanisms have been identified that drive motor and recovery after stroke: (1) salvation of penumbral tissue in the first days to weeks after stroke; (2) alleviation of diaschisis; (3) homeostatic and learning-dependent (Hebbian) neuroplasticity; (4) …behavioral compensation strategies. These mechanisms underlying recovery are highly interactive, and operate in different, sometimes limited, time-windows after stroke onset. In line with these mechanisms of improvement after stroke, we present a hypothetical phenomenological model for understanding skill reacquisition after stroke. Translational research is important at this point to improve our knowledge about the neural correlates of what and how patients learn when they show functional improvement after stroke. This knowledge should serve as a basis to optimize the timing, focus and intensity of evidence-based rehabilitation interventions and to design innovative strategies to enhance motor recovery after stroke. Show more

Keywords: Neuroplasticity, recovery, stroke, rehabilitation, paresis, hebbian learning

DOI: 10.3233/RNN-130332

Citation: Restorative Neurology and Neuroscience, vol. 31, no. 6, pp. 707-722, 2013

Authors: Chang, Won Seok | Roh, Daeyoung | Kim, Chan-Hyung | Chang, Jin Woo

Article Type: Research Article

Abstract: Background: The ventral capsule (VC), ventral striatum (VS), and the anterior cingulate gyrus are parts of the obsessive-compulsive disorder (OCD) and depression circuits. We assessed whether a combination of bilateral anterior cingulotomy and VC/VS deep brain stimulation (DBS) had an additive effect in patients with OCD and major depression. Methods: Three patients with refractory OCD underwent combined bilateral anterior cingulotomy and VC/VS DBS procedures. All patients met the inclusion criteria for the Korean guidelines of DBS for OCD. Baseline Yale-Brown Obsessive-Compulsive Disorder Scale (Y-BOCS) scores, Hamilton Depression Rating Scale scores, and global assessments of functioning were evaluated. These scores were …also serially estimated for more than 24 months after surgery at 3-month intervals. Results: The mean value of the baseline Y-BOCS scores was 34.7 (range 30–38); the mean Y-BOCS value decreased significantly to 23.0 (range 20–25) 3 months after the surgery. This score was maintained 2 years after surgery with a mean value of 19.0 (range 18–20). Conclusions: The combination of the two therapies did not yield superior outcomes, as the clinical outcomes were comparable to those of previous reports for VC/VS DBS alone. Wide-area VC/VS DBS may be sufficient to control refractory OCD. Show more

Keywords: Brain stimulation, depression, obsessive-compulsive disorder, treatment resistant

DOI: 10.3233/RNN-120290

Citation: Restorative Neurology and Neuroscience, vol. 31, no. 6, pp. 723-732, 2013

Authors: Wyss, Alexander F. | Hamadjida, Adjia | Savidan, Julie | Liu, Yu | Bashir, Shahid | Mir, Anis | Schwab, Martin E. | Rouiller, Eric M. | Belhaj-Saif, Abderaouf

Article Type: Research Article

Abstract: Purpose: How are motor maps modified within and in the immediate vicinity of a damaged zone in the motor cortex of non-human primates? Methods: In eight adult macaque monkeys subjected to a restricted chemical lesion of the hand area in the primary motor cortex (M1), motor maps were established using intracortical micro-stimulation (ICMS) techniques. The monkeys were subdivided into five animals without treatment, whereas three monkeys received an anti-Nogo-A antibody treatment. Results: Following permanent M1 injury, the lesion territory became largely non micro-excitable several months post-lesion, in spite of some recovery of hand function. Few sites within the lesion territory …remained excitable, though irrespective to the degree of functional recovery. Around the lesion in M1, there was no reallocation of proximal shoulder/arm territories into distal hand functions. However, ICMS delivered at supra-threshold intensities in these proximal territories elicited digit movements. Post-lesion ICMS thresholds to elicit movements of forelimb muscle territories increased, independently from the degree of functional recovery. Further behavioural evidence for an enhancement of functional recovery promoted by the anti-Nogo-A antibody treatment is provided. Conclusion: The degree of functional recovery is not related to a reorganization of motor maps within, and in the vicinity of, a M1 lesion. Show more

Keywords: Primates, intracortical microstimulation, somatotopy, neuroplasticity

DOI: 10.3233/RNN-130344

Citation: Restorative Neurology and Neuroscience, vol. 31, no. 6, pp. 733-760, 2013

Authors: Polanowska, Katarzyna Ewa | Leśniak, Marcin Maciej | Seniów, Joanna Barbara | Czepiel, Wojciech | Członkowska, Anna

Article Type: Research Article

Abstract: Purpose: Recent research in patients with chronic aphasia shows an association between excitatory anodal transcranial direct current stimulation (A-tDCS) of the stroke-affected left hemisphere coupled with speech and language therapy (SLT) and better language performance. The present study aimed to investigate this association during the early post-stroke rehabilitation period, when adaptive changes are most possible on neurophysiological and behavioral levels. Methods: We randomized 24 patients with non-fluent aphasia to receive 15 consecutive sessions (5 days/week for 3 weeks) of A-tDCS (1 mA, 10 min; n = 14) or sham tDCS (S-tDCS: 1 mA, 25 sec; n = 10) over Broca's …area followed by 45-min SLT. Naming ability was assessed before the rehabilitation, after its completion, and three months later. Results: Both groups significantly improved after the therapy. There were no statistically significant between-group differences in the short-term or long-term tDCS effects on naming accuracy and naming time. The A-tDCS group obtained higher effect sizes in naming time, both post-treatment and at the 3-month follow-up, suggesting potential benefits of the stimulation. Conclusions: The findings provide only weak evidence for A-tDCS-related language gains during early neurorehabilitation of post-stroke aphasia. Further research is needed to explore the effectiveness of this kind of neuromodulation. Show more

Keywords: aphasia, stroke, transcranial direct current stimulation, neuromodulation

DOI: 10.3233/RNN-130333

Citation: Restorative Neurology and Neuroscience, vol. 31, no. 6, pp. 761-771, 2013

Authors: Lee, Kyoung-Hee | Kim, Ji-Hye | Choi, Dong-Hee | Lee, Jongmin

Article Type: Research Article

Abstract: Purpose: To determine the optimal timing of rehabilitation and its role in corticospinal tract (CST) plasticity after stroke. Methods: Rats were subjected to photothrombotic infarct. The large stroke (LS) and small stroke (SS) groups were subdivided and task-specific training (TST) was initiated at 1, 5, or 14 days poststroke. Behavioral tests were performed at 2, 7, 14, 21, 28, and 35 days poststroke. The differences of axonal sprouting in the cortex, red nucleus, cerebral peduncle, and pyramid level were compared by immunohistochemistry. Results: SS groups with TST starting at 1 day and 5 days showed significantly better recovery in the …behavioral tests. LS group with TST starting at 5 days showed better recovery, while those with TST starting at 1 day showed worse recovery. Contralesional axonal sprouting was increased in both groups with TST starting at 5 days. However, it was decreased in the LS group with TST starting at 1 day. Transcallosal axonal sprouting from the contralesional motor cortex was increased in the LS group with TST starting at 5 days. Conclusions: Functional recovery after stroke may vary, depending on the lesion size and the timing of rehabilitation. The underlying mechanism may involve contralesional CST plasticity and transcallosal axonal sprouting. Show more

Keywords: Corticospinal tract plasticity, functional recovery, rehabilitation timing, stroke, task-specific training, transcallosal axonal sprouting

DOI: 10.3233/RNN-130336

Citation: Restorative Neurology and Neuroscience, vol. 31, no. 6, pp. 773-785, 2013

Authors: Sabel, Bernhard A. | Kruse, Rudolf | Wolf, Fred | Guenther, Tobias

Article Type: Research Article

Abstract: Purpose: Vision restoration training (VRT) in hemianopia patients leads to visual field enlargements, but the mechanisms of this vision restoration are not known. To investigate the role of residual vision in recovery, we studied topographic features of visual field charts and determined residual functions in local regions and their immediate surround. Methods: We analyzed High Resolution Perimetry visual field charts of hemianopic stroke patients (n = 23) before and after 6 months of VRT and identified all local visual field regions with (“hot spots”, n = 688) or without restoration (“cold spots”, n = 3426). Topographic features of these spots …at baseline where then related to (i) their respective local residual function, (ii) residual activity in their spatial neighbourhood, and (iii) their distance to the scotoma border estimated in cortical coordinates following magnification factor transformation. Results: Visual field areas had a greater probability of becoming vision restoration hot spots if they had more residual activity in both local areas and in a spatially limited surround of 5° of visual angle. Hot spots were typically also located closer than 4 mm from the scotoma border in cortical coordinates. Thus, restoration depended on residual activity in both the local region and its immediate surround. Conclusions: Our findings confirm the special role of residual structures in visual field restoration which is likely mediated by partially surviving neuronal elements. Because the immediate but not distant surround influenced outcome of individual spots, we propose that lateral interactions, known to play a role in perceptual learning and receptive field plasticity, also play a major role in vision restoration. Show more

Keywords: Vision, plasticity, restoration, recovery, rehabilitation

DOI: 10.3233/RNN-139019

Citation: Restorative Neurology and Neuroscience, vol. 31, no. 6, pp. 787-803, 2013

Article Type: Correction

Abstract: Erratum to http://dx.doi.org/10.3233/RNN-2012-110204

DOI: 10.3233/RNN-139018

Citation: Restorative Neurology and Neuroscience, vol. 31, no. 6, pp. 805-805, 2013