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Lian Y, Cheng X, Chen Q, Huang L, Xie L, Wang W, Ni J, Chen X. Case report: Beneficial effects of visual cortex tDCS stimulation combined with visual training in patients with visual field defects. Front Neurol 2024; 15:1344348. [PMID: 38327623 PMCID: PMC10847570 DOI: 10.3389/fneur.2024.1344348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 01/10/2024] [Indexed: 02/09/2024] Open
Abstract
Background Visual field defect (VFD) refers to the phenomenon that the eye is unable to see a certain area within the normal range of vision, which may be caused by eye diseases, neurological diseases and other reasons. Transcranial direct current stimulation (tDCS) is expected to be an effective treatment for the recovery or partial recovery of VFD. This paper describes the potential for tDCS in combination with visual retraining strategies to have a positive impact on vision recovery, and the potential for neuroplasticity to play a key role in vision recovery. Methods This case report includes two patients. Patient 1 was diagnosed with a right occipital hemorrhage and homonymous hemianopia. Patient 2 had multiple facial fractures, a contusion of the right eye, and damage to the optic nerve of the right eye, which was diagnosed as a peripheral nerve injury (optic nerve injury). We administered a series of treatments to two patients, including transcranial direct current stimulation; visual field restoration rehabilitation: paracentric gaze training, upper and lower visual field training, VR rehabilitation, and perceptual training. One time per day, 5 days per week, total 6 weeks. Results After 6 weeks of visual rehabilitation and tDCS treatment, Patient 1 Humphrey visual field examination showed a significant improvement compared to the initial visit, with a reduction in the extent of visual field defects, increased visual acuity, and improvement in most visual functions. Patient 2 had an expanded visual field, improved visual sensitivity, and substantial improvement in visual function. Conclusion Our case reports support the feasibility and effectiveness of tDCS combined with visual rehabilitation training in the treatment of occipital stroke and optic nerve injury settings.
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Affiliation(s)
- Yanhua Lian
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Department of Rehabilitation, Fuzhou Second Hospital, Fuzhou, China
| | - Xiaoping Cheng
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Qunlin Chen
- Department of Radiology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Libin Huang
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Lili Xie
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Wenzong Wang
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Jun Ni
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Xinyuan Chen
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Department of Rehabilitation Medicine, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
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2
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Lu Z, Zhou M, Guo T, Liang J, Wu W, Gao Q, Li L, Li H, Chai X. An in-silico analysis of retinal electric field distribution induced by different electrode design of trans-corneal electrical stimulation. J Neural Eng 2022; 19. [PMID: 36044887 DOI: 10.1088/1741-2552/ac8e32] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/31/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Trans-corneal electrical stimulation (TcES) produces therapeutic effects on many ophthalmic diseases non-invasively. Existing clinical TcES devices use largely variable design of electrode distribution and stimulation parameters. Better understanding of how electrode configuration paradigms and stimulation parameters influence the electric field distribution on the retina, will be beneficial to the design of next-generation TcES devices. APPROACH In this study, we constructed a realistic finite element human head model with fine eyeball structure. Commonly used DTL-Plus and ERG-Jet electrodes were simulated. We then conducted in silico investigations of retina observation surface (ROS) electric field distributions induced by different return electrode configuration paradigms and different stimulus intensities. MAIN RESULTS Our results suggested that the ROS electric field distribution could be modulated by re-designing TcES electrode settings and stimulus parameters. Under far return location (FRL) paradigms, either DTL-Plus or ERG-Jet approach could induce almost identical ROS electric field distribution regardless where the far return was located. However, compared with the ERG-Jet mode, DTL-Plus stimulation induced stronger nasal lateralization. In contrast, ERG-Jet stimulation induced relatively stronger temporal lateralization. The ROS lateralization can be further tweaked by changing the DTL-Plus electrode length. SIGNIFICANCE These results may contribute to the understanding of the characteristics of DTL-Plus and ERG-Jet electrodes based electric field distribution on the retina, providing practical implications for the therapeutic application of TcES.
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Affiliation(s)
- Zhuofan Lu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Address: 800 Dongchuan Road, Minhang District, Shanghai, Shanghai, 200240, CHINA
| | - Meixuan Zhou
- Shanghai Jiao Tong University, Shanghai 200240, Shanghai, 200240, CHINA
| | - Tianruo Guo
- GSBME, University of New South Wales, Graduate School of Biomedical Engineering, University of New South Wales, NSW 2052, Sydney, Australia, Sydney, New South Wales, 2052, AUSTRALIA
| | - Junling Liang
- Shanghai Jiao Tong University, Address: 800 Dongchuan Road, Minhang District, Shanghai Shanghai, CN 200240, Shanghai, 200240, CHINA
| | - Weilei Wu
- Shanghai Jiao Tong University, School of Biomedical Engineering Shanghai Jiao Tong University , Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai Shanghai, CN 200240, Shanghai, 200240, CHINA
| | - Qi Gao
- Shanghai Jiao Tong University, Address: 800 Dongchuan Road, Minhang District, Shanghai, Shanghai, 200240, CHINA
| | - Liming Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, Shanghai, 200240, CHINA
| | - Heng Li
- Shanghai Jiao Tong University, Address: 800 Dongchuan Road, Minhang District, Shanghai Shanghai, CN 200240, Shanghai, 200240, CHINA
| | - Xinyu Chai
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, Shanghai, 200240, CHINA
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Battaglini L, Di Ponzio M, Ghiani A, Mena F, Santacesaria P, Casco C. Vision recovery with perceptual learning and non-invasive brain stimulation: Experimental set-ups and recent results, a review of the literature. Restor Neurol Neurosci 2022; 40:137-168. [PMID: 35964213 DOI: 10.3233/rnn-221261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Vision is the sense which we rely on the most to interact with the environment and its integrity is fundamental for the quality of our life. However, around the globe, more than 1 billion people are affected by debilitating vision deficits. Therefore, finding a way to treat (or mitigate) them successfully is necessary. OBJECTIVE This narrative review aims to examine options for innovative treatment of visual disorders (retinitis pigmentosa, macular degeneration, optic neuropathy, refractory disorders, hemianopia, amblyopia), especially with Perceptual Learning (PL) and Electrical Stimulation (ES). METHODS ES and PL can enhance visual abilities in clinical populations, inducing plastic changes. We describe the experimental set-ups and discuss the results of studies using ES or PL or their combination in order to suggest, based on literature, which treatment is the best option for each clinical condition. RESULTS Positive results were obtained using ES and PL to enhance visual functions. For example, repetitive transorbital Alternating Current Stimulation (rtACS) appeared as the most effective treatment for pre-chiasmatic disorders such as optic neuropathy. A combination of transcranial Direct Current Stimulation (tDCS) and visual training seems helpful for people with hemianopia, while transcranial Random Noise Stimulation (tRNS) makes visual training more efficient in people with amblyopia and mild myopia. CONCLUSIONS This narrative review highlights the effect of different ES montages and PL in the treatment of visual disorders. Furthermore, new options for treatment are suggested. It is noteworthy to mention that, in some cases, unclear results emerged and others need to be more deeply investigated.
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Affiliation(s)
- Luca Battaglini
- Department of General Psychology, University of Padova, Italy.,Centro di Ateneo dei Servizi Clinici Universitari Psicologici (SCUP), University of Padova, Padova, Italy.,Neuro.Vis.U.S, University of Padova, Padova, Italy
| | - Michele Di Ponzio
- Department of General Psychology, University of Padova, Italy.,Istituto di Neuroscienze, Florence, Italy
| | - Andrea Ghiani
- Department of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, the Netherlands
| | - Federica Mena
- Department of General Psychology, University of Padova, Italy
| | | | - Clara Casco
- Department of General Psychology, University of Padova, Italy.,Centro di Ateneo dei Servizi Clinici Universitari Psicologici (SCUP), University of Padova, Padova, Italy.,Neuro.Vis.U.S, University of Padova, Padova, Italy
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4
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Levin LA, Patrick C, Choudry NB, Sharif NA, Goldberg JL. Neuroprotection in neurodegenerations of the brain and eye: Lessons from the past and directions for the future. Front Neurol 2022; 13:964197. [PMID: 36034312 PMCID: PMC9412944 DOI: 10.3389/fneur.2022.964197] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/20/2022] [Indexed: 12/24/2022] Open
Abstract
BackgroundNeurological and ophthalmological neurodegenerative diseases in large part share underlying biology and pathophysiology. Despite extensive preclinical research on neuroprotection that in many cases bridges and unifies both fields, only a handful of neuroprotective therapies have succeeded clinically in either.Main bodyUnderstanding the commonalities among brain and neuroretinal neurodegenerations can help develop innovative ways to improve translational success in neuroprotection research and emerging therapies. To do this, analysis of why translational research in neuroprotection fails necessitates addressing roadblocks at basic research and clinical trial levels. These include optimizing translational approaches with respect to biomarkers, therapeutic targets, treatments, animal models, and regulatory pathways.ConclusionThe common features of neurological and ophthalmological neurodegenerations are useful for outlining a path forward that should increase the likelihood of translational success in neuroprotective therapies.
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Affiliation(s)
- Leonard A. Levin
- Departments of Ophthalmology and Visual Sciences, Neurology & Neurosurgery, McGill University, Montreal, QC, Canada
- *Correspondence: Leonard A. Levin
| | | | - Nozhat B. Choudry
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, CA, United States
| | - Najam A. Sharif
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, CA, United States
| | - Jeffrey L. Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Palo Alto, CA, United States
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5
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Liu J, Ma AK, So KF, Lee VW, Chiu K. Mechanisms of electrical stimulation in eye diseases: A narrative review. ADVANCES IN OPHTHALMOLOGY PRACTICE AND RESEARCH 2022; 2:100060. [PMID: 37846384 PMCID: PMC10577855 DOI: 10.1016/j.aopr.2022.100060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/14/2022] [Accepted: 05/01/2022] [Indexed: 10/18/2023]
Abstract
Background In the last two decades, electrical stimulation (ES) has been tested in patients with various eye diseases and shows great treatment potential in retinitis pigmentosa and optic neuropathy. However, the clinical application of ES in ophthalmology is currently limited. On the one hand, optimization and standardization of ES protocols is still an unmet need. On the other hand, poor understanding of the underlying mechanisms has hindered clinical exploitation. Main Text Numerous experimental studies have been conducted to identify the treatment potential of ES in eye diseases and to explore the related cellular and molecular mechanisms. In this review, we summarized the in vitro and in vivo evidence related to cellular and tissue response to ES in eye diseases. We highlighted several pathways that may be utilized by ES to impose its effects on the diseased retina. Conclusions Therapeutic effect of ES in retinal degenerative diseases might through preventing neuronal apoptosis, promoting neuronal regeneration, increasing neurotrophic factors production in Müller cells, inhibiting microglial activation, enhancing retinal blood flow, and modulating brain plasticity. Future studies are suggested to analyse changes in specific retinal cells for optimizing the treatment parameters and choosing the best fit ES delivery method in target diseases.
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Affiliation(s)
- Jinfeng Liu
- Department of Ophthalmology, The University of Hong Kong, SAR, Hong Kong, China
| | | | - Kwok Fai So
- Department of Ophthalmology, The University of Hong Kong, SAR, Hong Kong, China
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, SAR, Hong Kong, China
- Department of Psychology, The University of Hong Kong, SAR, Hong Kong, China
- Guangdong-Hong Kong-Macau Institute of Central Nervous System Regeneration, Jinan University, Guangzhou, China
| | - Vincent W.H. Lee
- Department of Ophthalmology, The University of Hong Kong, SAR, Hong Kong, China
| | - Kin Chiu
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, SAR, Hong Kong, China
- Department of Psychology, The University of Hong Kong, SAR, Hong Kong, China
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6
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Dragon AK, Korchazhkina NB, Sheludchenko VM, Yusef Y, Kosova JV, Makarova MA, Elfimov MA. [Results of the application of complex physiotherapeutic neurostimulation in optical neuropathies of various genesis]. VOPROSY KURORTOLOGII, FIZIOTERAPII, I LECHEBNOI FIZICHESKOI KULTURY 2022; 99:72-77. [PMID: 36083821 DOI: 10.17116/kurort20229904272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
UNLABELLED Optical neuropathies (ON) are the outcome of many diseases of various origins. The main ones are classified as inflammatory, vascular and traumatic ON. ON lead to subatrophy of the optic nerve, but even after the completion of treatment, it is possible to improve visual functions by using physiotherapeutic means of ophthalmic rehabilitation. OBJECTIVE To evaluate the effectiveness of complex physiotherapeutic neuro-ophthalmostimulation in case of ON of vascular origin. MATERIAL AND METHODS The study included 60 patients (120 eyes) with a verified diagnosis of optic neuropathy of vascular origin, who were divided into 2 groups comparable in age, gender and anatomical and functional characteristics: the main group of 30 patients (60 eyes) and the control group - 30 patients (60 eyes), including 24 men and 36 women, mean age was 66.2±4.1 years, disease duration was 4.1±1.7 years. All patients underwent courses of conservative treatment with vitamins according to the available ophthalmological standards, repeating them 1-2 times a year, the last of which was six months before the present study. Physiotherapy courses and patients did not pass. 20 healthy volunteers were taken to create basic indicators of the «norm» of the applied research methods. Patients of the main group used a set of procedures: transcranial magnetic electrical stimulation, endonasal electrophoresis with the drug neuroprotector Semax 0.1%, oxybaric chamber and acupuncture. Patients in the control group were prescribed basic therapy, including taking the vitamin complex BEROCCA for 3 months. Breakpoints: before treatment and at times: 1st week, 12 weeks and 24 weeks after the course of treatment, according to the standard recommendations for international multicenter studies. The following were assessed: visual field boundaries (dilation meridians; in deg.), light sensitivity (MS, MD; in dB), indicators of the state of the retinal ganglion layer (GCS thickness, volume loss): Avg CCG (in µm), FLV, GLV (in %). RESULTS When evaluating the results in patients of the main group who received complex neurostimulation, the therapeutic efficacy in a week after the end of treatment was 94%, in 12 weeks - in 88% and in 24 weeks - 83%, while in patients of the control group for all studied indicators showed only a positive trend and therapeutic efficacy did not exceed 30-42%. CONCLUSION Under the influence of the developed neurostimulating complex, the activity of nerve cells objectively increases, leading to a significant increase in the boundaries of the field of view and light sensitivity and a decrease in global losses of the retinal ganglion complex and optic nerve.
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Affiliation(s)
- A K Dragon
- Research Institute of Eye Diseases, Moscow, Russia
| | | | | | - Yu Yusef
- Research Institute of Eye Diseases, Moscow, Russia
| | - J V Kosova
- Research Institute of Eye Diseases, Moscow, Russia
| | - M A Makarova
- Research Institute of Eye Diseases, Moscow, Russia
| | - M A Elfimov
- Research Institute of Eye Diseases, Moscow, Russia
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7
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Sabel BA, Zhou W, Huber F, Schmidt F, Sabel K, Gonschorek A, Bilc M. Non-invasive brain microcurrent stimulation therapy of long-COVID-19 reduces vascular dysregulation and improves visual and cognitive impairment. Restor Neurol Neurosci 2021; 39:393-408. [PMID: 34924406 PMCID: PMC8764598 DOI: 10.3233/rnn-211249] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND An effective treatment is needed for long-COVID patients which suffer from symptoms of vision and/or cognition impairment such as impaired attention, memory, language comprehension, or fatigue. OBJECTIVE Because COVID-19infection causes reduced blood flow which may cause neuronal inactivation, we explored if neuromodulation with non-invasive brain stimulation using microcurrent (NIBS), known to enhance blood flow and neuronal synchronization, can reduce these symptoms. METHODS Two female long-COVID patients were treated for 10-13 days with alternating current stimulation of the eyes and brain. While one patient (age 40) was infected with the SARS CoV-2 virus, the other (age 72) developed symptoms following AstraZeneca vaccination. Before and after therapy, cognition was assessed subjectively by interview and visual fields quantified using perimetry. One patient was also tested with a cognitive test battery and with a retinal dynamic vascular analyser (DVA), a surrogate marker of vascular dysregulation in the brain. RESULTS In both patients NIBS markedly improved cognition and partially reversed visual field loss within 3-4 days. Cognitive tests in one patient confirmed recovery of up to 40-60% in cognitive subfunctions with perimetry results showing stable and visual field recovery even during follow-up. DVA showed that NIBS reduced vascular dysregulation by normalizing vessel dynamics (dilation/constriction), with particularly noticeable changes in the peripheral veins and arteries. CONCLUSIONS NIBS was effective in improving visual and cognitive deficits in two confirmed SARS-COV-2 patients. Because recovery of function was associated with restoration of vascular autoregulation, we propose that (i) hypometabolic, "silent" neurons are the likely biological cause of long-COVID associated visual and cognitive deficits, and (ii) reoxygenation of these "silent" neurons provides the basis for neural reactivation and neurological recovery. Controlled trials are now needed to confirm these observations.
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Affiliation(s)
- Bernhard A Sabel
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University of Magdeburg, Magdeburg, Germany
| | - Wanshu Zhou
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University of Magdeburg, Magdeburg, Germany
| | - Frank Huber
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University of Magdeburg, Magdeburg, Germany
| | - Florentina Schmidt
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University of Magdeburg, Magdeburg, Germany
| | | | | | - Mirela Bilc
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University of Magdeburg, Magdeburg, Germany
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8
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Xu J, Wu Z, Nürnberger A, Sabel BA. Reorganization of Brain Functional Connectivity Network and Vision Restoration Following Combined tACS-tDCS Treatment After Occipital Stroke. Front Neurol 2021; 12:729703. [PMID: 34777199 PMCID: PMC8580405 DOI: 10.3389/fneur.2021.729703] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/17/2021] [Indexed: 01/01/2023] Open
Abstract
Objective: Non-invasive brain stimulation (NIBS) is already known to improve visual field functions in patients with optic nerve damage and partially restores the organization of brain functional connectivity networks (FCNs). However, because little is known if NIBS is effective also following brain damage, we now studied the correlation between visual field recovery and FCN reorganization in patients with stroke of the central visual pathway. Method: In a controlled, exploratory trial, 24 patients with hemianopia were randomly assigned to one of three brain stimulation groups: transcranial direct current stimulation (tDCS)/transcranial alternating current stimulation (tACS) (ACDC); sham tDCS/tACS (AC); sham tDCS/sham tACS (Sham), which were compared to age-matched controls (n = 24). Resting-state electroencephalogram (EEG) was collected at baseline, after 10 days stimulation and at 2 months follow-up. EEG recordings were analyzed for FCN measures using graph theory parameters, and FCN small worldness of the network and long pairwise coherence parameter alterations were then correlated with visual field performance. Result: ACDC enhanced alpha-band FCN strength in the superior occipital lobe of the lesioned hemisphere at follow-up. A negative correlation (r = −0.80) was found between the intact visual field size and characteristic path length (CPL) after ACDC with a trend of decreased alpha-band centrality of the intact middle occipital cortex. ACDC also significantly decreased delta band coherence between the lesion and the intact occipital lobe, and coherence was enhanced between occipital and temporal lobe of the intact hemisphere in the low beta band. Responders showed significantly higher strength in the low alpha band at follow-up in the intact lingual and calcarine cortex and in the superior occipital region of the lesioned hemisphere. Conclusion: While ACDC decreases delta band coherence between intact and damaged occipital brain areas indicating inhibition of low-frequency neural oscillations, ACDC increases FCN connectivity between the occipital and temporal lobe in the intact hemisphere. When taken together with the lower global clustering coefficient in responders, these findings suggest that FCN reorganization (here induced by NIBS) is adaptive in stroke. It leads to greater efficiency of neural processing, where the FCN requires fewer connections for visual processing.
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Affiliation(s)
- Jiahua Xu
- Institute of Medical Psychology, Medical Faculty, Otto-V.-Guericke University of Magdeburg, Magdeburg, Germany.,Faculty of Computer Science, Otto-V.-Guericke University of Magdeburg, Magdeburg, Germany
| | - Zheng Wu
- Institute of Medical Psychology, Medical Faculty, Otto-V.-Guericke University of Magdeburg, Magdeburg, Germany.,Faculty of Computer Science, Otto-V.-Guericke University of Magdeburg, Magdeburg, Germany
| | - Andreas Nürnberger
- Faculty of Computer Science, Otto-V.-Guericke University of Magdeburg, Magdeburg, Germany
| | - Bernhard A Sabel
- Institute of Medical Psychology, Medical Faculty, Otto-V.-Guericke University of Magdeburg, Magdeburg, Germany
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9
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Sabel BA, Kresinsky A, Cardenas-Morales L, Haueisen J, Hunold A, Dannhauer M, Antal A. Evaluating Current Density Modeling of Non-Invasive Eye and Brain Electrical Stimulation Using Phosphene Thresholds. IEEE Trans Neural Syst Rehabil Eng 2021; 29:2133-2141. [PMID: 34648453 PMCID: PMC8594910 DOI: 10.1109/tnsre.2021.3120148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Because current flow cannot be measured directly in the intact retina or brain, current density distribution models were developed to estimate it during magnetic or electrical stimulation. A paradigm is now needed to evaluate if current flow modeling can be related to physiologically meaningful signs of true current distribution in the human brain. We used phosphene threshold measurements (PTs) as surrogate markers of current-flow to determine if PTs, evoked by transcranial alternating current stimulation (tACS), can be matched with current density estimates generated by head model-based computer simulations. Healthy, male subjects (n=15) were subjected to three-staged PT measurements comparing six unilateral and one bilateral stimulation electrode montages according to the 10/20 system: Fp2-Suborbital right (So), Fp2-right shoulder (rS), Fp2-Cz, Fp2- O2, So-rS, Cz-F8 and F7-F8. The stimulation frequency was set at 16 Hz. Subjects were asked to report the appearance and localization of phosphenes in their visual field for every montage. Current density models were built using multi-modal imaging data of a standard brain, meshed with isotropic conductivities of different tissues of the head using the SimBio and SCIRun software packages. We observed that lower PTs were associated with higher simulated current levels in the unilateral montages of the model head, and shorter electrode distances to the eye had lower PTs. The lowest mean PT and the lowest variability were found in the F7-F8 montage (95±33 μA). Our results confirm the hypothesis that phosphenes are primarily of retinal origin, and they provide the first in vivo evidence that computer models of current flow using head models are a valid tool to estimate real current flow in the human eye and brain.
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10
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Blum MC, Hunold A, Solf B, Klee S. Ocular direct current stimulation affects retinal ganglion cells. Sci Rep 2021; 11:17573. [PMID: 34475417 PMCID: PMC8413326 DOI: 10.1038/s41598-021-96401-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 08/09/2021] [Indexed: 11/22/2022] Open
Abstract
Ocular current stimulation (oCS) with weak current intensities (a few mA) has shown positive effects on retinal nerve cells, which indicates that neurodegenerative ocular diseases could be treated with current stimulation of the eye. During oCS, a significant polarity-independent reduction in the characteristic P50 amplitude of a pattern-reversal electroretinogram was found, while no current stimulation effect was found for a full field electroretinogram (ffERG). The ffERG data indicated a trend for a polarity-dependent influence during oCS on the photopic negative response (PhNR) wave, which represents the sum activity of the retinal ganglion cells. Therefore, an ffERG with adjusted parameters for the standardized measurement of the PhNR wave was combined with simultaneous oCS to study the potential effects of direct oCS on cumulative ganglion cell activity. Compared with that measured before oCS, the PhNR amplitude in the cathodal group increased significantly during current stimulation, while in the anodal and sham groups, no effect was visible (α = 0.05, pcathodal = 0.006*). Furthermore, repeated-measures ANOVA revealed a significant difference in PhNR amplitude between the anodal and cathodal groups as well as between the cathodal and sham groups (p* ≤ 0.0167, pcathodal − anodal = 0.002*, pcathodal − sham = 0.011*).
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Affiliation(s)
- Maren-Christina Blum
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany.
| | - Alexander Hunold
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Benjamin Solf
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Sascha Klee
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany.,Department of General Health Studies, Division Biostatistics and Data Science, Karl Landsteiner University of Health Sciences, Krems, Austria
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11
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Liu J, Tong K, Lin Y, Lee VWH, So KF, Shih KC, Lai JSM, Chiu K. Effectiveness of Microcurrent Stimulation in Preserving Retinal Function of Blind Leading Retinal Degeneration and Optic Neuropathy: A Systematic Review. Neuromodulation 2021; 24:992-1002. [PMID: 33984873 DOI: 10.1111/ner.13414] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/29/2021] [Accepted: 04/19/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To systematically identify and summarize the effectiveness and the parameters of electrical stimulation (ES) for the preservation of visual function in major retinal degeneration and optic neuropathy. MATERIALS AND METHODS A systematic review of clinical studies, using ES therapy in patients with blind leading retinal degenerations, including retinitis pigmentosa (RP), age-related macular degeneration (AMD), glaucoma, retinal vein occlusion (RVO), retinal artery occlusion (RAO), and optic neuropathy was conducted. PubMed, EMBASE, Cochrane Library, and Web of Science were searched for relevant interventional studies including randomized controlled trials (RCTs) and observational studies. RESULTS A total of 10 RCTs and 15 observational studies were included. Transcorneal ES (TcES), transpalpebral ES (TpES), transdermal ES (TdES), and repetitive transorbital alternating current stimulation (rtACS) were used for the treatment of the patients. ES using 20 Hz biphasic pulses with current strength at 150%-200% of individual electrical phosphene threshold (EPT) for RP patients showed improved retinal function detected by visual acuity (VA), visual field (VF), or electrical retinal graphs (ERG). rtACS on patients with optic neuropathy showed significant preservation of VA and VF. Clinical studies on AMD, RAO, and glaucoma indicated promising protective effects of ES on the visual function, though the amount of evidence is limited. CONCLUSIONS ES treatment has promising therapeutic effects on RP and optic neuropathy. More large-scale RCT studies should be conducted to elucidate the potential of ES, especially on AMD, RAO, and glaucoma. A comparison of the effects by different ES methods in the same disease populations is still lacking. Parameters of the electric current and sensitive detection method should be optimized for the evaluation of ES treatment effects in future studies.
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Affiliation(s)
- Jinfeng Liu
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Kelvin Tong
- Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Youhong Lin
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Vincent W H Lee
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Kwok Fai So
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China.,Guangdong HongKong Macau Institute of CNS Regeneration: Guangdong, Guangzhou, China
| | - Kendrick Co Shih
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Jimmy S M Lai
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Kin Chiu
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China
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12
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Multi-channel transorbital electrical stimulation for effective stimulation of posterior retina. Sci Rep 2021; 11:9745. [PMID: 33963229 PMCID: PMC8105361 DOI: 10.1038/s41598-021-89243-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 04/23/2021] [Indexed: 02/03/2023] Open
Abstract
Transorbital electrical stimulation (tES) has been studied as a new noninvasive method for treating intractable eye diseases by delivering weak electrical current to the eye through a pair of electrodes attached to the skin around the eye. Studies have reported that the therapeutic effect of tES is determined by the effective stimulation of retinal cells that are densely distributed in the posterior part of the retina. However, in conventional tES with a pair of electrodes, a greater portion of the electric field is delivered to the anterior part of the retina. In this study, to address this issue, a new electrode montage with multiple electrodes was proposed for the effective delivery of electric fields to the posterior retina. Electric field analysis based on the finite element method was performed with a realistic human head model, and optimal injection currents were determined using constrained convex optimization. The resultant electric field distributions showed that the proposed multi-channel tES enables a more effective stimulation of the posterior retina than the conventional tES with a pair of electrodes.
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13
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Blum MC, Solf B, Hunold A, Klee S. Effects of Ocular Direct Current Stimulation on Full Field Electroretinogram. Front Neurosci 2021; 15:606557. [PMID: 33679299 PMCID: PMC7928396 DOI: 10.3389/fnins.2021.606557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/11/2021] [Indexed: 12/14/2022] Open
Abstract
Studies on weak current stimulation (1-2 mA) examine effects on neuronal cells for the treatment of neurological diseases, like depression. Ocular current stimulation showed positive effects on retinal nerve cells which indicate that neurodegenerative ocular diseases, e.g., glaucoma, can be treated with current stimulation of the eye. However, up to now it remains unclear which exact retinal cells can be influenced. During an ocular direct current stimulation, a significant reduction of the characteristic P50 amplitude of a pattern-reversal electroretinogram (PERG) was found for an anodal and a cathodal stimulation. This current stimulation effect could originate from the modulation of pre-ganglion cell activity or by changes in local ON and OFF responses of ganglion cells. For clarification, we investigate acute direct current stimulation effects on a full field electroretinogram (ERG), which represents the activity of pre-ganglion cells (specifically cones and bipolar cells). The ERG from 15 subjects was evaluated before (ERG 1) and during (ERG 2) an ocular direct current stimulation with 800 μA over 5 min. The current was applied through a ring rubber electrode placed around the eye and a 25 cm2 rubber electrode placed at the ipsilateral temple. For ERG measurements, sintered Ag/AgCl skin-electrodes were positioned on the lower eyelid (active), the earlobe (reference), and the forehead (ground). The volunteers were stimulated in three independent sessions, each with a different current application (randomized order): cathodal polarity, anodal polarity (referred to the electrode around the eye), or sham stimulation. The changes between the two ERG measurements of the characteristic full field ERG amplitudes, a-wave, b-wave, and b'-wave (b-wave measured from zero line) were tested with the Wilcoxon signed-rank test (α = 0.05). Comparing before to during the current stimulation for all applications, the ERG waves showed no effects on amplitudes or latencies. Furthermore, no significant difference between the cathodal, anodal, and sham stimulation could be found by a Friedman test. These results indicate an unlikely contribution of pre-ganglion cells to the previously reported stimulation effect on PERG signals.
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Affiliation(s)
- Maren-Christina Blum
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
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14
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Żebrowska M, Dzwiniel P, Waleszczyk WJ. Removal of the Sinusoidal Transorbital Alternating Current Stimulation Artifact From Simultaneous EEG Recordings: Effects of Simple Moving Average Parameters. Front Neurosci 2020; 14:735. [PMID: 32848538 PMCID: PMC7403449 DOI: 10.3389/fnins.2020.00735] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 06/22/2020] [Indexed: 02/02/2023] Open
Abstract
Alternating current stimulation is a promising method for the study and treatment of various visual neurological dysfunctions as well as progressive understanding of the healthy brain. Unfortunately, due to the current stimulation artifact, problems remain in the context of analysis of the electroencephalography (EEG) signal recorded during ongoing stimulation. To address this problem, we propose the use of a simple moving average subtraction as a method for artifact elimination. This method involves the creation of a template of the stimulation artifact from EEG signal recorded during non-invasive electrical stimulation with a sinusoidal alternating current. The present report describes results of the effects of a simple moving average filtration that varies based on averaging parameters; in particular, we varied the number of sinusoidal periods per segment of the recorded signal and the number of segments used to construct an artifact template. Given the ongoing lack of a mathematical model that allows for the prediction of the “hidden” EEG signal with the alternating current stimulation artifact, we propose performing an earlier simulation that is based on the addition of artificial stimulation artifact to the known EEG signal. This solution allows for the optimization of filtering parameters with detailed knowledge about the accuracy of artifact removal. The algorithm, designed in the MATLAB environment, has been tested on data recorded from two volunteers subjected to sinusoidal transorbital alternating current stimulation. Analysis of the percentage difference between the original and filtered signal in time and frequency domain highlights the advantage of 1-period filtration.
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Affiliation(s)
- Małgorzata Żebrowska
- Laboratory of Visual Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland.,Faculty of Physics, Warsaw University of Technology, Warsaw, Poland
| | - Piotr Dzwiniel
- Laboratory of Visual Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - Wioletta Joanna Waleszczyk
- Laboratory of Visual Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
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15
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Perin C, Viganò B, Piscitelli D, Matteo BM, Meroni R, Cerri CG. Non-invasive current stimulation in vision recovery: a review of the literature. Restor Neurol Neurosci 2020; 38:239-250. [PMID: 31884495 PMCID: PMC7504999 DOI: 10.3233/rnn-190948] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Background: Around 253 million people worldwide suffer from irreversible visual damage. Numerous studies have been carried out in order to unveil the effects of electrical stimulation (ES) as a useful tool for rehabilitation for different visual conditions and pathologies. Objective: This systematic review aimed to 1) examine the current evidence of ES efficacy for the treatment of visual pathologies and 2) define the corresponding degree of the recommendation of different ES techniques. Methods: A systematic review was conducted in MEDLINE and Cochrane Library database to collect documents published between 2000 and 2018. For each study, Level of Evidence of Effectiveness of ES as well as the Class of Quality for the treatment of different visual pathologies were determined. Results: Thirty-eight articles were included. Studies were grouped according to the pathology treated and the type of stimulation administered. The first group included studies treating pre-chiasmatic pathologies (age-related macular degeneration, macular dystrophy, retinal artery occlusion, retinitis pigmentosa, glaucoma, optic nerve damage, and optic neuropathy) using pre-chiasmatic stimulation; the second group included studies treating both pre-chiasmatic pathologies (amblyopia, myopia) and post-chiasmatic pathologies or brain conditions (hemianopsia, brain trauma) by means of post-chiasmatic stimulation. In the first group, repetitive transorbital alternating current stimulation (rtACS) reached level A recommendation, and transcorneal electrical stimulation (tcES) reached level B. In the second group, both high-frequency random noise stimulation (hf-RNS) and transcranial direct current stimulation (tDCS) reached level C recommendation. Conclusions: Study’s findings suggest conclusive evidence for rtACS treatment. For other protocols results are promising but not conclusive since the examined studies assessed different stimulation parameters and endpoints. A comparison of the effects of different combinations of these variables still lacks in the literature. Further studies are needed to optimize existing protocols and determine if different protocols are needed for different diseases.
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Affiliation(s)
- Cecilia Perin
- Dipartimento di Medicina e Chirurgia (School of Medicine and Surgery), University of Milan-Bicocca, Milan, Italy.,Milan Center for Neuroscience (NeuroMI), University of Milan-Bicocca, Milan, Italy
| | | | - Daniele Piscitelli
- Dipartimento di Medicina e Chirurgia (School of Medicine and Surgery), University of Milan-Bicocca, Milan, Italy.,School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada
| | - Barbara Maria Matteo
- Dipartimento di Medicina e Chirurgia (School of Medicine and Surgery), University of Milan-Bicocca, Milan, Italy
| | - Roberto Meroni
- Dipartimento di Medicina e Chirurgia (School of Medicine and Surgery), University of Milan-Bicocca, Milan, Italy.,Milan Center for Neuroscience (NeuroMI), University of Milan-Bicocca, Milan, Italy.,Current Affilation: Department of Physiotherapy, LUNEX International University of Health, Exercise and Sports. Differdange, Luxembourg
| | - Cesare Giuseppe Cerri
- Dipartimento di Medicina e Chirurgia (School of Medicine and Surgery), University of Milan-Bicocca, Milan, Italy.,Milan Center for Neuroscience (NeuroMI), University of Milan-Bicocca, Milan, Italy
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16
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Blum MC, Hunold A, Solf B, Klee S. The Effects of an Ocular Direct Electrical Stimulation on Pattern-Reversal Electroretinogram. Front Neurosci 2020; 14:588. [PMID: 32587502 PMCID: PMC7298143 DOI: 10.3389/fnins.2020.00588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/13/2020] [Indexed: 02/02/2023] Open
Abstract
Studies on transcranial current stimulation have shown that a direct current stimulation of the occipital cortex can influence the amplitude size of a visual evoked potential (VEP). The current direction (cathodal or anodal) determines whether the VEP amplitudes increase or decrease. The aim of this study was to design a new experimental setup that will enable a simultaneous ocular direct current stimulation and electroretinogram (ERG) recording which will broaden our understanding of current stimulation effects on the visual system. Furthermore, we examined whether a direct current stimulation on the eye has a similar effect on an ERG as on a VEP. The pattern-reversal ERG was measured with sintered Ag/AgCl skin-electrodes, positioned on the lower eyelid (active), the earlobe (reference), and the forehead (ground). Direct current was applied through a ring rubber electrode placed around the eye and a 5 cm × 5 cm rubber electrode placed at the ipsilateral temple with a current strength of 500 μA and a duration time of 5 min. Fifty-seven healthy volunteers were divided into three groups depending on the current direction (cathodal, anodal, and sham stimulation, n = 19 each). One ERG measurement (ERG 1) was performed before and another (ERG 2) during the direct current stimulation. The difference between ERG 1 and ERG 2 measurements for the characteristic P50, N95 and N95' (N95 minimum measured from zero line) amplitudes were evaluated by both confidence interval analysis and t-test for related samples (α = 0.05, after Bonferroni correction p ∗ = 0.0055). The P50 amplitude was significantly decreased for ERG 2 measurement in the cathodal and anodal stimulation group (cathodal p = 0.001, anodal p = 0.000). No significant changes could be found in the N95 and N95' amplitudes as well as in the sham-stimulation group. Additionally, the latencies did not undergo any significant changes. In conclusion, the newly designed experimental setup enables simultaneous current stimulation and ERG recording. The current influenced P50 amplitude although not the N95 and N95' amplitudes. Furthermore, the amplitude size decreased for both current directions and did not lead to contrary effects as expected.
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Affiliation(s)
- Maren-Christina Blum
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
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17
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Transorbital electrical stimulation in retinitis pigmentosa. Better results joining visual pattern stimulation? Brain Stimul 2020; 13:1173-1174. [PMID: 32497738 DOI: 10.1016/j.brs.2020.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 05/28/2020] [Indexed: 11/23/2022] Open
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18
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Adair D, Truong D, Esmaeilpour Z, Gebodh N, Borges H, Ho L, Bremner JD, Badran BW, Napadow V, Clark VP, Bikson M. Electrical stimulation of cranial nerves in cognition and disease. Brain Stimul 2020; 13:717-750. [PMID: 32289703 PMCID: PMC7196013 DOI: 10.1016/j.brs.2020.02.019] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 02/13/2020] [Accepted: 02/17/2020] [Indexed: 02/06/2023] Open
Abstract
The cranial nerves are the pathways through which environmental information (sensation) is directly communicated to the brain, leading to perception, and giving rise to higher cognition. Because cranial nerves determine and modulate brain function, invasive and non-invasive cranial nerve electrical stimulation methods have applications in the clinical, behavioral, and cognitive domains. Among other neuromodulation approaches such as peripheral, transcranial and deep brain stimulation, cranial nerve stimulation is unique in allowing axon pathway-specific engagement of brain circuits, including thalamo-cortical networks. In this review we amalgamate relevant knowledge of 1) cranial nerve anatomy and biophysics; 2) evidence of the modulatory effects of cranial nerves on cognition; 3) clinical and behavioral outcomes of cranial nerve stimulation; and 4) biomarkers of nerve target engagement including physiology, electroencephalography, neuroimaging, and behavioral metrics. Existing non-invasive stimulation methods cannot feasibly activate the axons of only individual cranial nerves. Even with invasive stimulation methods, selective targeting of one nerve fiber type requires nuance since each nerve is composed of functionally distinct axon-types that differentially branch and can anastomose onto other nerves. None-the-less, precisely controlling stimulation parameters can aid in affecting distinct sets of axons, thus supporting specific actions on cognition and behavior. To this end, a rubric for reproducible dose-response stimulation parameters is defined here. Given that afferent cranial nerve axons project directly to the brain, targeting structures (e.g. thalamus, cortex) that are critical nodes in higher order brain networks, potent effects on cognition are plausible. We propose an intervention design framework based on driving cranial nerve pathways in targeted brain circuits, which are in turn linked to specific higher cognitive processes. State-of-the-art current flow models that are used to explain and design cranial-nerve-activating stimulation technology require multi-scale detail that includes: gross anatomy; skull foramina and superficial tissue layers; and precise nerve morphology. Detailed simulations also predict that some non-invasive electrical or magnetic stimulation approaches that do not intend to modulate cranial nerves per se, such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS), may also modulate activity of specific cranial nerves. Much prior cranial nerve stimulation work was conceptually limited to the production of sensory perception, with individual titration of intensity based on the level of perception and tolerability. However, disregarding sensory emulation allows consideration of temporal stimulation patterns (axon recruitment) that modulate the tone of cortical networks independent of sensory cortices, without necessarily titrating perception. For example, leveraging the role of the thalamus as a gatekeeper for information to the cerebral cortex, preventing or enhancing the passage of specific information depending on the behavioral state. We show that properly parameterized computational models at multiple scales are needed to rationally optimize neuromodulation that target sets of cranial nerves, determining which and how specific brain circuitries are modulated, which can in turn influence cognition in a designed manner.
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Affiliation(s)
- Devin Adair
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Dennis Truong
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Zeinab Esmaeilpour
- Department of Biomedical Engineering, City College of New York, New York, NY, USA.
| | - Nigel Gebodh
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Helen Borges
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Libby Ho
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - J Douglas Bremner
- Department of Psychiatry & Behavioral Sciences and Radiology, Emory University School of Medicine, Atlanta, GA, USA; Atlanta VA Medical Center, Decatur, GA, USA
| | - Bashar W Badran
- Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Vitaly Napadow
- Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Harvard medical school, Boston, MA, USA
| | - Vincent P Clark
- Psychology Clinical Neuroscience Center, Dept. Psychology, MSC03-2220, University of New Mexico, Albuquerque, NM, 87131, USA; Department of Psychology, University of New Mexico, Albuquerque, NM, 87131, USA; The Mind Research Network of the Lovelace Biomedical Research Institute, 1101 Yale Blvd. NE, Albuquerque, NM, 87106, USA
| | - Marom Bikson
- Department of Biomedical Engineering, City College of New York, New York, NY, USA.
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19
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Personality and stress influence vision restoration and recovery in glaucoma and optic neuropathy following alternating current stimulation: implications for personalized neuromodulation and rehabilitation. EPMA J 2020; 11:177-196. [PMID: 32547650 PMCID: PMC7272530 DOI: 10.1007/s13167-020-00204-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/12/2020] [Indexed: 12/20/2022]
Abstract
Purpose Identifying factors that affect recovery or restoration of neurological function is a key goal of rehabilitation in neurology and ophthalmology. One such factor can be prolonged mental stress, which may be not only the consequence of nervous system damage but also a major risk factor, or cause, of neural inactivation. Using the visual system as a model of neural injury, we wished to study how patients' stress and personality profiles correlate with vision recovery as induced by therapy with alternating current stimulation (ACS) in patients with optic nerve damage. Methods Personality and stress questionnaires were sent retrospectively to a clinical convenience sample of patients who suffer low vision due to optic nerve damage, which had previously been treated with ACS. The questionnaires included the NEO Five-Factor Inventory (NEO-FFI), the Trier Inventory of Chronic Stress (TICS), and the Flammer syndrome (FS) checklist, which probes signs of vascular dysregulation (VD). These scores were then correlated with the extent of ACS-induced vision restoration as recorded 1-3 years earlier by perimetric visual field tests. Results Two NEO-FFI personality factors (lower neuroticism, higher conscientiousness) and the presence of physiological Flammer signs were associated with greater recovery as were individual items of the factors openness and agreeableness. Single NEO-FFI item analysis revealed that recovery relates to greater extraversion (optimistic and happy), openness (less guided by authorities for decisions on moral issues), and agreeableness (argue less, like working with others, thoughtful, considerate) as well as the presence of FS signs (cold hands/feet, hypotension, slim body shapes, tinnitus). This suggests that patients with better recovery were more calm, peaceful and secure, hard-working, and reliable, and with high organizational skills. In contrast, patients with poor recovery had a tendency to be emotionally unstable, anxious, unhappy and prone to negative emotions, impulsive, careless, and unorganized. Chronic stress assessed with TICS did not correlate with recovery. Conclusion Vision restoration induced by ACS is greater in patients with less stress-prone personality traits and those who show signs of VD. Prospective studies are now needed to determine if personality has (i) a causal influence, i.e., patients with less stress-prone personalities and greater VD signs recover better, and/or (ii) if personality changes are an effect of the treatment, i.e., successful recovery induces personality changes. Though the cause-effect relationship is still open, we nevertheless propose that psychosocial factors and VD contribute to the highly variable outcome of vision restoration treatments in low vision rehabilitation. This has implications for preventive and personalized vision restoration and is of general value for our understanding of outcome variability in neuromodulation and neurological rehabilitation.
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20
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Grasso PA, Gallina J, Bertini C. Shaping the visual system: cortical and subcortical plasticity in the intact and the lesioned brain. Neuropsychologia 2020; 142:107464. [PMID: 32289349 DOI: 10.1016/j.neuropsychologia.2020.107464] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/08/2020] [Indexed: 02/06/2023]
Abstract
Visual system is endowed with an incredibly complex organization composed of multiple visual pathway affording both hierarchical and parallel processing. Even if most of the visual information is conveyed by the retina to the lateral geniculate nucleus of the thalamus and then to primary visual cortex, a wealth of alternative subcortical pathways is present. This complex organization is experience dependent and retains plastic properties throughout the lifespan enabling the system with a continuous update of its functions in response to variable external needs. Changes can be induced by several factors including learning and experience but can also be promoted by the use non-invasive brain stimulation techniques. Furthermore, besides the astonishing ability of our visual system to spontaneously reorganize after injuries, we now know that the exposure to specific rehabilitative training can produce not only important functional modifications but also long-lasting changes within cortical and subcortical structures. The present review aims to update and address the current state of the art on these topics gathering studies that reported relevant modifications of visual functioning together with plastic changes within cortical and subcortical structures both in the healthy and in the lesioned visual system.
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Affiliation(s)
- Paolo A Grasso
- Department of Neuroscience, Psychology, Pharmacology and Child Health, University of Florence, Florence, 50135, Italy.
| | - Jessica Gallina
- Department of Psychology, University of Bologna, Bologna, 40127, Italy; CsrNC, Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, 47521, Italy
| | - Caterina Bertini
- Department of Psychology, University of Bologna, Bologna, 40127, Italy; CsrNC, Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, 47521, Italy
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21
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Sabel BA, Gao Y, Antal A. Reversibility of visual field defects through induction of brain plasticity: vision restoration, recovery and rehabilitation using alternating current stimulation. Neural Regen Res 2020; 15:1799-1806. [PMID: 32246620 PMCID: PMC7513964 DOI: 10.4103/1673-5374.280302] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
For decades visual field defects were considered irreversible because it was thought that in the visual system the regeneration potential of the neuronal tissues is low. Nevertheless, there is always some potential for partial recovery of the visual field defect that can be achieved through induction of neuroplasticity. Neuroplasticity refers to the ability of the brain to change its own functional architecture by modulating synaptic efficacy. It is maintained throughout life and just as neurological rehabilitation can improve motor coordination, visual field defects in glaucoma, diabetic retinopathy or optic neuropathy can be improved by inducing neuroplasticity. In ophthalmology many new treatment paradigms have been tested that can induce neuroplastic changes, including non-invasive alternating current stimulation. Treatment with alternating current stimulation (e.g., 30 minutes, daily for 10 days using transorbital electrodes and ~10 Hz) activates the entire retina and parts of the brain. Electroencephalography and functional magnetic resonance imaging studies revealed local activation of the visual cortex, global reorganization of functional brain networks, and enhanced blood flow, which together activate neurons and their networks. The future of low vision is optimistic because vision loss is indeed, partially reversible.
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Affiliation(s)
- Bernhard A Sabel
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University of Magdeburg; Center for Behavioral and Brain Sciences (CBBS); Sabel Vision Restoration Center, Magdeburg, Germany
| | - Ying Gao
- Sabel Vision Restoration Center, Magdeburg, Germany
| | - Andrea Antal
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University of Magdeburg, Magdeburg; Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
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22
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Sabel BA, Thut G, Haueisen J, Henrich-Noack P, Herrmann CS, Hunold A, Kammer T, Matteo B, Sergeeva EG, Waleszczyk W, Antal A. Vision modulation, plasticity and restoration using non-invasive brain stimulation – An IFCN-sponsored review. Clin Neurophysiol 2020; 131:887-911. [DOI: 10.1016/j.clinph.2020.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 12/18/2019] [Accepted: 01/02/2020] [Indexed: 12/11/2022]
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23
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Su X, Zheng H, Li Q, Sun P, Zhou M, Li H, Guo J, Chai X, Zhou C. Retinal neurovascular responses to transcorneal electrical stimulation measured with optical coherence tomography. Exp Biol Med (Maywood) 2020; 245:289-300. [PMID: 31958987 DOI: 10.1177/1535370219900495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Noninvasive transcorneal electrical stimulation (TES) has emerged as a potential strategy to facilitate visual restoration and promote retinal cell survival for certain retinal and optic nerve diseases owing to its neuroprotective effects. However, the neurovascular responses of retinal neurons evoked by TES have not been completely determined. To investigate this issue, we utilized a custom-designed spectral-domain optical coherence tomography (SD-OCT) to record the retinal neural and vascular responses under TES in vivo simultaneously. Significant increases of both positive and negative intrinsic optical signal (IOS) changes were recorded in all three segmented retinal layers, which mainly related to neural activities. However, the changes of TES-induced retinal vascular responses, including blood velocity, cross-sectional area of vessel, and blood flow, were not significant. It suggests that TES mainly elicited neural responses in retina, while no significant vascular responses were evoked. Our results provide experimental evidence to the mechanism of retinal neurovascular coupling under TES. Additionally, the present study also suggests that SD-OCT could be utilized as a promoting method to explore neurovascular responses under retinal stimulation in clinical treatment and technology. Impact statement Noninvasive transcorneal electrical stimulation (TES) has emerged as an effective treatment for certain retinal and optic nerve diseases owing to its neuroprotective effects. However, the retinal neurovascular responses evoked by TES have not been completely determined. To investigate this issue, we utilized a custom-designed spectral-domain optical coherence tomography (SD-OCT) to record the retinal neural and vascular responses evoked by TES in vivo simultaneously. The present study suggested that TES mainly elicited neural responses in retina, while no significant vascular responses were evoked. Our results provide experimental evidence to the mechanism of retinal neurovascular coupling evoked by TES. Additionally, the present study also suggests that SD-OCT could be utilized as a promoting method to explore neurovascular responses under retinal electrical stimulation.
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Affiliation(s)
- Xiaofan Su
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hao Zheng
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qian Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna 1090, Austria
| | - Pengcheng Sun
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Meixuan Zhou
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Heng Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jiahui Guo
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xinyu Chai
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chuanqing Zhou
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.,Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shenzhen 518055, China
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Claes M, De Groef L, Moons L. Target-Derived Neurotrophic Factor Deprivation Puts Retinal Ganglion Cells on Death Row: Cold Hard Evidence and Caveats. Int J Mol Sci 2019; 20:E4314. [PMID: 31484425 PMCID: PMC6747494 DOI: 10.3390/ijms20174314] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/28/2019] [Accepted: 08/30/2019] [Indexed: 12/14/2022] Open
Abstract
Glaucoma and other optic neuropathies are characterized by axonal transport deficits. Axonal cargo travels back and forth between the soma and the axon terminus, a mechanism ensuring homeostasis and the viability of a neuron. An example of vital molecules in the axonal cargo are neurotrophic factors (NTFs). Hindered retrograde transport can cause a scarcity of those factors in the retina, which in turn can tilt the fate of retinal ganglion cells (RGCs) towards apoptosis. This postulation is one of the most widely recognized theories to explain RGC death in the disease progression of glaucoma and is known as the NTF deprivation theory. For several decades, research has been focused on the use of NTFs as a novel neuroprotective glaucoma treatment. Until now, results in animal models have been promising, but translation to the clinic has been highly disappointing. Are we lacking important knowledge to lever NTF therapies towards the therapeutic armamentarium? Or did we get the wrong end of the stick regarding the NTF deprivation theory? In this review, we will tackle the existing evidence and caveats advocating for and against the target-derived NTF deprivation theory in glaucoma, whilst digging into associated therapy efforts.
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Affiliation(s)
- Marie Claes
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lies De Groef
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium.
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Faiq MA, Wollstein G, Schuman JS, Chan KC. Cholinergic nervous system and glaucoma: From basic science to clinical applications. Prog Retin Eye Res 2019; 72:100767. [PMID: 31242454 PMCID: PMC6739176 DOI: 10.1016/j.preteyeres.2019.06.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/19/2019] [Accepted: 06/21/2019] [Indexed: 02/08/2023]
Abstract
The cholinergic system has a crucial role to play in visual function. Although cholinergic drugs have been a focus of attention as glaucoma medications for reducing eye pressure, little is known about the potential modality for neuronal survival and/or enhancement in visual impairments. Citicoline, a naturally occurring compound and FDA approved dietary supplement, is a nootropic agent that is recently demonstrated to be effective in ameliorating ischemic stroke, traumatic brain injury, Parkinson's disease, Alzheimer's disease, cerebrovascular diseases, memory disorders and attention-deficit/hyperactivity disorder in both humans and animal models. The mechanisms of its action appear to be multifarious including (i) preservation of cardiolipin, sphingomyelin, and arachidonic acid contents of phosphatidylcholine and phosphatidylethanolamine, (ii) restoration of phosphatidylcholine, (iii) stimulation of glutathione synthesis, (iv) lowering glutamate concentrations and preventing glutamate excitotoxicity, (v) rescuing mitochondrial function thereby preventing oxidative damage and onset of neuronal apoptosis, (vi) synthesis of myelin leading to improvement in neuronal membrane integrity, (vii) improving acetylcholine synthesis and thereby reducing the effects of mental stress and (viii) preventing endothelial dysfunction. Such effects have vouched for citicoline as a neuroprotective, neurorestorative and neuroregenerative agent. Retinal ganglion cells are neurons with long myelinated axons which provide a strong rationale for citicoline use in visual pathway disorders. Since glaucoma is a form of neurodegeneration involving retinal ganglion cells, citicoline may help ameliorate glaucomatous damages in multiple facets. Additionally, trans-synaptic degeneration has been identified in humans and experimental models of glaucoma suggesting the cholinergic system as a new brain target for glaucoma management and therapy.
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Affiliation(s)
- Muneeb A Faiq
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Gadi Wollstein
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Joel S Schuman
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Kevin C Chan
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States; Department of Radiology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States; Center for Neural Science, Faculty of Arts and Science, New York University, New York, NY, United States.
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Bikson M, Esmaeilpour Z, Adair D, Kronberg G, Tyler WJ, Antal A, Datta A, Sabel BA, Nitsche MA, Loo C, Edwards D, Ekhtiari H, Knotkova H, Woods AJ, Hampstead BM, Badran BW, Peterchev AV. Transcranial electrical stimulation nomenclature. Brain Stimul 2019; 12:1349-1366. [PMID: 31358456 DOI: 10.1016/j.brs.2019.07.010] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 06/25/2019] [Accepted: 07/14/2019] [Indexed: 01/03/2023] Open
Abstract
Transcranial electrical stimulation (tES) aims to alter brain function non-invasively by applying current to electrodes on the scalp. Decades of research and technological advancement are associated with a growing diversity of tES methods and the associated nomenclature for describing these methods. Whether intended to produce a specific response so the brain can be studied or lead to a more enduring change in behavior (e.g. for treatment), the motivations for using tES have themselves influenced the evolution of nomenclature, leading to some scientific, clinical, and public confusion. This ambiguity arises from (i) the infinite parameter space available in designing tES methods of application and (ii) varied naming conventions based upon the intended effects and/or methods of application. Here, we compile a cohesive nomenclature for contemporary tES technologies that respects existing and historical norms, while incorporating insight and classifications based on state-of-the-art findings. We consolidate and clarify existing terminology conventions, but do not aim to create new nomenclature. The presented nomenclature aims to balance adopting broad definitions that encourage flexibility and innovation in research approaches, against classification specificity that minimizes ambiguity about protocols but can hinder progress. Constructive research around tES classification, such as transcranial direct current stimulation (tDCS), should allow some variations in protocol but also distinguish from approaches that bear so little resemblance that their safety and efficacy should not be compared directly. The proposed framework includes terms in contemporary use across peer-reviewed publications, including relatively new nomenclature introduced in the past decade, such as transcranial alternating current stimulation (tACS) and transcranial pulsed current stimulation (tPCS), as well as terms with long historical use such as electroconvulsive therapy (ECT). We also define commonly used terms-of-the-trade including electrode, lead, anode, and cathode, whose prior use, in varied contexts, can also be a source of confusion. This comprehensive clarification of nomenclature and associated preliminary proposals for standardized terminology can support the development of consensus on efficacy, safety, and regulatory standards.
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Affiliation(s)
- Marom Bikson
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA.
| | - Zeinab Esmaeilpour
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA.
| | - Devin Adair
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA
| | - Greg Kronberg
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA
| | - William J Tyler
- Arizona State University, School of Biological and Health Systems Engineering, Tempe, AZ, USA
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center Goettingen, Goettingen, Germany; Institute of Medical Psychology, Medical Faculty, Otto-v.-Guericke University of Magdeburg, Magdeburg, Germany
| | | | - Bernhard A Sabel
- Institute of Medical Psychology, Medical Faculty, Otto-v.-Guericke University of Magdeburg, Magdeburg, Germany
| | - Michael A Nitsche
- Leibniz Research Centre for Working Environment ant Human Factors, Dept. Psychology and Neurosciences, Dortmund, Germany; University Medical Hospital Bergmannsheil, Dept. Neurology, Bochum, Germany
| | - Colleen Loo
- School of Psychiatry & Black Dog Institute, University of New South Wales, Sydney, Australia
| | - Dylan Edwards
- Moss Rehabilitation Research Institute, Philadelphia, PA, USA; Edith Cowan University, Joondalup, Australia
| | | | - Helena Knotkova
- MJHS Institute for Innovation in Palliative Care, New York, NY, USA; Department of Family and Social Medicine, Albert Einstein College of Medicine, The Bronx, NY, USA
| | - Adam J Woods
- Center for Cognitive Aging and Memory, McKnight Brain Institute, Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Benjamin M Hampstead
- Mental Health Service, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA; Neuropsychology Section, Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
| | - Bashar W Badran
- Department of Psychiatry, Medical University of South Carolina, Charleston, SC, USA
| | - Angel V Peterchev
- Department of Psychiatry & Behavioral Sciences, Department of Biomedical Engineering, Department of Electrical & Computer Engineering, Department of Neurosurgery, Duke University, Durham, NC, USA
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Sabel BA, Hamid AIA, Borrmann C, Speck O, Antal A. Transorbital alternating current stimulation modifies BOLD activity in healthy subjects and in a stroke patient with hemianopia: A 7 Tesla fMRI feasibility study. Int J Psychophysiol 2019; 154:80-92. [PMID: 30978369 DOI: 10.1016/j.ijpsycho.2019.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 03/28/2019] [Accepted: 04/04/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Modifying brain activity using non-invasive, low intensity transcranial electrical brain stimulation (TES) has rapidly increased during the past 20 years. Alternating current stimulation (ACS), for example, has been shown to alter brain rhythm activities and modify neuronal functioning in the visual system. Daily application of transorbital ACS to patients with optic nerve damage induces functional connectivity reorganization, and partially restores vision. While ACS is thought to mainly modify neuronal mechanisms, e.g. changes in brain oscillations that can be detected by EEG, it is still an open question, whether and how it may alter BOLD activity. OBJECTIVE We evaluated whether transorbital ACS modulates BOLD activity in early visual cortex using high-resolution 7 Tesla functional magnetic resonance imaging (fMRI). METHODS In this feasibility study transorbital ACS in the alpha range and sham ACS was applied in a random block design in five healthy subjects for 20 min at 1 mA. Brain activation in the visual areas V1, V2 and V3 were measured using 7 Tesla fMRI-based retinotopic mapping at the time points before (baseline) and after stimulation. In addition, we collected data from one hemianopic stroke patient with visual cortex damage after ten daily sessions with 25-50 min stimulation duration. RESULTS In healthy subjects transorbital ACS increased the activated cortical surface area, decreased the fMRI response amplitude and increased coherence in the visual cortex, which was most prominent in the full field task. In the patient, stimulation improved contrast sensitivity in the central visual field. BOLD amplitudes and coherence values were increased in most early visual areas in both hemispheres, with the most pronounced activation detected during eccentricity testing in retinotopic mapping. CONCLUSIONS This feasibility study showed that transorbital ACS modifies BOLD activity to visual stimulation, which outlasts the duration of the AC stimulation. This is in line with earlier neurophysiological findings of increased power in EEG recordings and functional connectivity reorganization in patients with impaired vision. Accordingly, the larger BOLD response area after stimulation can be explained by more coherent activation and lower variability in the activation. Alternatively, increased neuronal activity can also be taken into account. Controlled trials are needed to systematically evaluate the potential of repetitive transorbital ACS to improve visual function after visual pathway stroke and to determine the cause-effect relationship between neural and BOLD activity changes.
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Affiliation(s)
- Bernhard A Sabel
- Institute of Medical Psychology, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany.
| | - Aini Ismafairus Abd Hamid
- Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany; Department of Neurosciences, School of Medical Sciences Health Campus, Jalan Hospital USM, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Carolin Borrmann
- Institute of Medical Psychology, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany
| | - Oliver Speck
- Center for Behavioral Brain Sciences, Magdeburg, Germany; Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany; Department of Neurosciences, School of Medical Sciences Health Campus, Jalan Hospital USM, 16150 Kubang Kerian, Kelantan, Malaysia; Leibniz Institute for Neurobiology, Magdeburg, Germany; German Center for Neurodegenerative Disease (DZNE), Germany
| | - Andrea Antal
- Institute of Medical Psychology, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany; Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
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Pardue MT, Allen RS. Neuroprotective strategies for retinal disease. Prog Retin Eye Res 2018; 65:50-76. [PMID: 29481975 PMCID: PMC6081194 DOI: 10.1016/j.preteyeres.2018.02.002] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/14/2018] [Accepted: 02/20/2018] [Indexed: 12/20/2022]
Abstract
Diseases that affect the eye, including photoreceptor degeneration, diabetic retinopathy, and glaucoma, affect 11.8 million people in the US, resulting in vision loss and blindness. Loss of sight affects patient quality of life and puts an economic burden both on individuals and the greater healthcare system. Despite the urgent need for treatments, few effective options currently exist in the clinic. Here, we review research on promising neuroprotective strategies that promote neuronal survival with the potential to protect against vision loss and retinal cell death. Due to the large number of neuroprotective strategies, we restricted our review to approaches that we had direct experience with in the laboratory. We focus on drugs that target survival pathways, including bile acids like UDCA and TUDCA, steroid hormones like progesterone, therapies that target retinal dopamine, and neurotrophic factors. In addition, we review rehabilitative methods that increase endogenous repair mechanisms, including exercise and electrical stimulation therapies. For each approach, we provide background on the neuroprotective strategy, including history of use in other diseases; describe potential mechanisms of action; review the body of research performed in the retina thus far, both in animals and in humans; and discuss considerations when translating each treatment to the clinic and to the retina, including which therapies show the most promise for each retinal disease. Despite the high incidence of retinal diseases and the complexity of mechanisms involved, several promising neuroprotective treatments provide hope to prevent blindness. We discuss attractive candidates here with the goal of furthering retinal research in critical areas to rapidly translate neuroprotective strategies into the clinic.
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Affiliation(s)
- Machelle T Pardue
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, 1670 Clairmont Road, Decatur, GA, 30033, USA; Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Drive, Atlanta, GA, 30332, USA.
| | - Rachael S Allen
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, 1670 Clairmont Road, Decatur, GA, 30033, USA
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29
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Sun P, Li H, Lu Z, Su X, Ma Z, Chen J, Li L, Zhou C, Chen Y, Chai X. Comparison of cortical responses to the activation of retina by visual stimulation and transcorneal electrical stimulation. Brain Stimul 2018. [DOI: 10.1016/j.brs.2018.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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30
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Sabel BA, Wang J, Cárdenas-Morales L, Faiq M, Heim C. Mental stress as consequence and cause of vision loss: the dawn of psychosomatic ophthalmology for preventive and personalized medicine. EPMA J 2018; 9:133-160. [PMID: 29896314 PMCID: PMC5972137 DOI: 10.1007/s13167-018-0136-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/18/2018] [Indexed: 12/14/2022]
Abstract
The loss of vision after damage to the retina, optic nerve, or brain has often grave consequences in everyday life such as problems with recognizing faces, reading, or mobility. Because vision loss is considered to be irreversible and often progressive, patients experience continuous mental stress due to worries, anxiety, or fear with secondary consequences such as depression and social isolation. While prolonged mental stress is clearly a consequence of vision loss, it may also aggravate the situation. In fact, continuous stress and elevated cortisol levels negatively impact the eye and brain due to autonomous nervous system (sympathetic) imbalance and vascular dysregulation; hence stress may also be one of the major causes of visual system diseases such as glaucoma and optic neuropathy. Although stress is a known risk factor, its causal role in the development or progression of certain visual system disorders is not widely appreciated. This review of the literature discusses the relationship of stress and ophthalmological diseases. We conclude that stress is both consequence and cause of vision loss. This creates a vicious cycle of a downward spiral, in which initial vision loss creates stress which further accelerates vision loss, creating even more stress and so forth. This new psychosomatic perspective has several implications for clinical practice. Firstly, stress reduction and relaxation techniques (e.g., meditation, autogenic training, stress management training, and psychotherapy to learn to cope) should be recommended not only as complementary to traditional treatments of vision loss but possibly as preventive means to reduce progression of vision loss. Secondly, doctors should try their best to inculcate positivity and optimism in their patients while giving them the information the patients are entitled to, especially regarding the important value of stress reduction. In this way, the vicious cycle could be interrupted. More clinical studies are now needed to confirm the causal role of stress in different low vision diseases to evaluate the efficacy of different anti-stress therapies for preventing progression and improving vision recovery and restoration in randomized trials as a foundation of psychosomatic ophthalmology.
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Affiliation(s)
- Bernhard A. Sabel
- Institute of Medical Psychology, Medical Faculty, Otto von Guericke University of Magdeburg, Magdeburg, Germany
| | - Jiaqi Wang
- Institute of Medical Psychology, Medical Faculty, Otto von Guericke University of Magdeburg, Magdeburg, Germany
| | - Lizbeth Cárdenas-Morales
- Institute of Medical Psychology, Medical Faculty, Otto von Guericke University of Magdeburg, Magdeburg, Germany
| | - Muneeb Faiq
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, 110029 India
- Department of Ophthalmology, NYU Langone Health, New York University School of Medicine, New York, NY USA
| | - Christine Heim
- Berlin Institute of Health (BIH), Institute of Medical Psychology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA USA
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Dzwiniel P, Gola M, Wójcik-Gryciuk A, Waleszczyk WJ. Specvis: Free and open-source software for visual field examination. PLoS One 2017; 12:e0186224. [PMID: 29028825 PMCID: PMC5640235 DOI: 10.1371/journal.pone.0186224] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 09/27/2017] [Indexed: 12/26/2022] Open
Abstract
Visual field impairment affects more than 100 million people globally. However, due to the lack of the access to appropriate ophthalmic healthcare in undeveloped regions as a result of associated costs and expertise this number may be an underestimate. Improved access to affordable diagnostic software designed for visual field examination could slow the progression of diseases, such as glaucoma, allowing for early diagnosis and intervention. We have developed Specvis, a free and open-source application written in Java programming language that can run on any personal computer to meet this requirement (http://www.specvis.pl/). Specvis was tested on glaucomatous, retinitis pigmentosa and stroke patients and the results were compared to results using the Medmont M700 Automated Static Perimeter. The application was also tested for inter-test intrapersonal variability. The results from both validation studies indicated low inter-test intrapersonal variability, and suitable reliability for a fast and simple assessment of visual field impairment. Specvis easily identifies visual field areas of zero sensitivity and allows for evaluation of its levels throughout the visual field. Thus, Specvis is a new, reliable application that can be successfully used for visual field examination and can fill the gap between confrontation and perimetry tests. The main advantages of Specvis over existing methods are its availability (free), affordability (runs on any personal computer), and reliability (comparable to high-cost solutions).
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Affiliation(s)
- Piotr Dzwiniel
- Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - Mateusz Gola
- Institute of Psychology of the Polish Academy of Sciences, Warsaw, Poland
- Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California, San Diego, California, United States of America
| | - Anna Wójcik-Gryciuk
- Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
- Mediq Clinic, Legionowo, Poland
| | - Wioletta J. Waleszczyk
- Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
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Antal A, Alekseichuk I, Bikson M, Brockmöller J, Brunoni AR, Chen R, Cohen LG, Dowthwaite G, Ellrich J, Flöel A, Fregni F, George MS, Hamilton R, Haueisen J, Herrmann CS, Hummel FC, Lefaucheur JP, Liebetanz D, Loo CK, McCaig CD, Miniussi C, Miranda PC, Moliadze V, Nitsche MA, Nowak R, Padberg F, Pascual-Leone A, Poppendieck W, Priori A, Rossi S, Rossini PM, Rothwell J, Rueger MA, Ruffini G, Schellhorn K, Siebner HR, Ugawa Y, Wexler A, Ziemann U, Hallett M, Paulus W. Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines. Clin Neurophysiol 2017; 128:1774-1809. [PMID: 28709880 PMCID: PMC5985830 DOI: 10.1016/j.clinph.2017.06.001] [Citation(s) in RCA: 646] [Impact Index Per Article: 92.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/29/2017] [Accepted: 06/06/2017] [Indexed: 12/11/2022]
Abstract
Low intensity transcranial electrical stimulation (TES) in humans, encompassing transcranial direct current (tDCS), transcutaneous spinal Direct Current Stimulation (tsDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation or their combinations, appears to be safe. No serious adverse events (SAEs) have been reported so far in over 18,000 sessions administered to healthy subjects, neurological and psychiatric patients, as summarized here. Moderate adverse events (AEs), as defined by the necessity to intervene, are rare, and include skin burns with tDCS due to suboptimal electrode-skin contact. Very rarely mania or hypomania was induced in patients with depression (11 documented cases), yet a causal relationship is difficult to prove because of the low incidence rate and limited numbers of subjects in controlled trials. Mild AEs (MAEs) include headache and fatigue following stimulation as well as prickling and burning sensations occurring during tDCS at peak-to-baseline intensities of 1-2mA and during tACS at higher peak-to-peak intensities above 2mA. The prevalence of published AEs is different in studies specifically assessing AEs vs. those not assessing them, being higher in the former. AEs are frequently reported by individuals receiving placebo stimulation. The profile of AEs in terms of frequency, magnitude and type is comparable in healthy and clinical populations, and this is also the case for more vulnerable populations, such as children, elderly persons, or pregnant women. Combined interventions (e.g., co-application of drugs, electrophysiological measurements, neuroimaging) were not associated with further safety issues. Safety is established for low-intensity 'conventional' TES defined as <4mA, up to 60min duration per day. Animal studies and modeling evidence indicate that brain injury could occur at predicted current densities in the brain of 6.3-13A/m2 that are over an order of magnitude above those produced by tDCS in humans. Using AC stimulation fewer AEs were reported compared to DC. In specific paradigms with amplitudes of up to 10mA, frequencies in the kHz range appear to be safe. In this paper we provide structured interviews and recommend their use in future controlled studies, in particular when trying to extend the parameters applied. We also discuss recent regulatory issues, reporting practices and ethical issues. These recommendations achieved consensus in a meeting, which took place in Göttingen, Germany, on September 6-7, 2016 and were refined thereafter by email correspondence.
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Affiliation(s)
- A Antal
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg August University, Göttingen, Germany.
| | - I Alekseichuk
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - M Bikson
- Department of Biomedical Engineering, The City College of New York, New York, USA
| | - J Brockmöller
- Department of Clinical Pharmacology, University Medical Center Goettingen, Germany
| | - A R Brunoni
- Service of Interdisciplinary Neuromodulation, Department and Institute of Psychiatry, Laboratory of Neurosciences (LIM-27) and Interdisciplinary Center for Applied Neuromodulation University Hospital, University of São Paulo, São Paulo, Brazil
| | - R Chen
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Research Institute, Toronto, Ontario, Canada
| | - L G Cohen
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke NIH, Bethesda, USA
| | | | - J Ellrich
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark; Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, Erlangen, Germany; EBS Technologies GmbH, Europarc Dreilinden, Germany
| | - A Flöel
- Universitätsmedizin Greifswald, Klinik und Poliklinik für Neurologie, Greifswald, Germany
| | - F Fregni
- Spaulding Neuromodulation Center, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA
| | - M S George
- Brain Stimulation Division, Medical University of South Carolina, and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, USA
| | - R Hamilton
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - J Haueisen
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Germany
| | - C S Herrmann
- Experimental Psychology Lab, Department of Psychology, European Medical School, Carl von Ossietzky Universität, Oldenburg, Germany
| | - F C Hummel
- Defitech Chair of Clinical Neuroengineering, Centre of Neuroprosthetics (CNP) and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland; Defitech Chair of Clinical Neuroengineering, Clinique Romande de Réadaptation, Swiss Federal Institute of Technology (EPFL Valais), Sion, Switzerland
| | - J P Lefaucheur
- Department of Physiology, Henri Mondor Hospital, Assistance Publique - Hôpitaux de Paris, and EA 4391, Nerve Excitability and Therapeutic Team (ENT), Faculty of Medicine, Paris Est Créteil University, Créteil, France
| | - D Liebetanz
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - C K Loo
- School of Psychiatry & Black Dog Institute, University of New South Wales, Sydney, Australia
| | - C D McCaig
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK
| | - C Miniussi
- Center for Mind/Brain Sciences CIMeC, University of Trento, Rovereto, Italy; Cognitive Neuroscience Section, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - P C Miranda
- Institute of Biophysics and Biomedical Engineering, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - V Moliadze
- Institute of Medical Psychology and Medical Sociology, University Hospital of Schleswig-Holstein (UKSH), Campus Kiel, Christian-Albrechts-University, Kiel, Germany
| | - M A Nitsche
- Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany; Department of Neurology, University Hospital Bergmannsheil, Bochum, Germany
| | - R Nowak
- Neuroelectrics, Barcelona, Spain
| | - F Padberg
- Department of Psychiatry and Psychotherapy, Munich Center for Brain Stimulation, Ludwig-Maximilian University Munich, Germany
| | - A Pascual-Leone
- Division of Cognitive Neurology, Harvard Medical Center and Berenson-Allen Center for Noninvasive Brain Stimulation at Beth Israel Deaconess Medical Center, Boston, USA
| | - W Poppendieck
- Department of Information Technology, Mannheim University of Applied Sciences, Mannheim, Germany
| | - A Priori
- Center for Neurotechnology and Experimental Brain Therapeutich, Department of Health Sciences, University of Milan Italy; Deparment of Clinical Neurology, University Hospital Asst Santi Paolo E Carlo, Milan, Italy
| | - S Rossi
- Department of Medicine, Surgery and Neuroscience, Human Physiology Section and Neurology and Clinical Neurophysiology Section, Brain Investigation & Neuromodulation Lab, University of Siena, Italy
| | - P M Rossini
- Area of Neuroscience, Institute of Neurology, University Clinic A. Gemelli, Catholic University, Rome, Italy
| | | | - M A Rueger
- Department of Neurology, University Hospital of Cologne, Germany
| | | | | | - H R Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark
| | - Y Ugawa
- Department of Neurology, Fukushima Medical University, Fukushima, Japan; Fukushima Global Medical Science Center, Advanced Clinical Research Center, Fukushima Medical University, Japan
| | - A Wexler
- Department of Science, Technology & Society, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - U Ziemann
- Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - M Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - W Paulus
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
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Electrical Stimulation as a Means for Improving Vision. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 186:2783-2797. [PMID: 27643530 DOI: 10.1016/j.ajpath.2016.07.017] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/12/2016] [Accepted: 07/14/2016] [Indexed: 12/31/2022]
Abstract
Evolving research has provided evidence that noninvasive electrical stimulation (ES) of the eye may be a promising therapy for either preserving or restoring vision in several retinal and optic nerve diseases. In this review, we focus on minimally invasive strategies for the delivery of ES and accordingly summarize the current literature on transcorneal, transorbital, and transpalpebral ES in both animal experiments and clinical studies. Various mechanisms are believed to underlie the effects of ES, including increased production of neurotrophic agents, improved chorioretinal blood circulation, and inhibition of proinflammatory cytokines. Different animal models have demonstrated favorable effects of ES on both the retina and the optic nerve. Promising effects of ES have also been demonstrated in clinical studies; however, all current studies have a lack of randomization and/or a control group (sham). There is thus a pressing need for a deeper understanding of the underlying mechanisms that govern clinical success and optimization of stimulation parameters in animal studies. In addition, such research should be followed by large, prospective, clinical studies to explore the full potential of ES. Through this review, we aim to provide insight to guide future research on ES as a potential therapy for improving vision.
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Matsumoto H, Ugawa Y. Adverse events of tDCS and tACS: A review. Clin Neurophysiol Pract 2016; 2:19-25. [PMID: 30214966 PMCID: PMC6123849 DOI: 10.1016/j.cnp.2016.12.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/02/2016] [Accepted: 12/05/2016] [Indexed: 01/25/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) have been applied to many research issues because these stimulation techniques can modulate neural activity in the human brain painlessly and non-invasively with weak electrical currents. However, there are no formal safety guidelines for the selection of stimulus parameters in either tDCS or tACS. As a means of gathering the information that is needed to produce safety guidelines, in this article, we summarize the adverse events of tDCS and tACS. In both stimulation techniques, most adverse effects are mild and disappear soon after stimulation. Nevertheless, several papers have reported that, in tDCS, some adverse events persist even after stimulation. The persistent events consist of skin lesions similar to burns, which can arise even in healthy subjects, and mania or hypomania in patients with depression. Recently, one paper reported a pediatric patient presenting with seizure after tDCS, although the causal relationship between stimulation and seizure is not clear. As this seizure is the only serious adverse events yet reported in connection with tDCS, tDCS is considered safe. In tACS, meanwhile, no persistent adverse events have been reported, but considerably fewer reports are available on the safety of tACS than on the safety of tDCS. Therefore, to establish the safety of tDCS and tACS, we need to scan the literature continuously for information on the adverse events of both stimulation techniques. Further safety investigations are also required.
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Affiliation(s)
| | - Yoshikazu Ugawa
- Department of Neurology, School of Medicine, Fukushima Medical University, Japan.,Fukushima Global Medical Science Center, Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan
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Rahmatnejad K, Ahmed OM, Waisbourd M, Katz LJ. Non-invasive electrical stimulation for vision restoration: dream or reality? EXPERT REVIEW OF OPHTHALMOLOGY 2016. [DOI: 10.1080/17469899.2016.1221761] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sergeeva EG, Henrich-Noack P, Gorkin AG, Sabel BA. Preclinical model of transcorneal alternating current stimulation in freely moving rats. Restor Neurol Neurosci 2016; 33:761-9. [PMID: 25813371 DOI: 10.3233/rnn-150513] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE Transcorneal alternating current stimulation (tACS) has become a promising tool to modulate brain functions and treat visual diseases. To understand the mechanisms of action a suitable animal model is required. However, because existing animal models employ narcosis, which interferes with brain oscillations and stimulation effects, we developed an experimental setup where current stimulation via the eye and flicker light stimulation can be applied while simultaneously recording local field potentials in awake rats. METHOD tACS was applied in freely-moving rats (N = 24) which had wires implanted under their upper eye lids. Field potential recordings were made in visual cortex and superior colliculus. To measure visual evoked responses, rats were exposed to flicker-light using LEDs positioned in headset spectacles. RESULTS Corneal electrodes and recording assemblies were reliably operating and well tolerated for at least 4 weeks. Transcorneal stimulation without narcosis did not induce any adverse reactions. Stable head stages allowed repetitive and long-lasting recordings of visual and electrically evoked potentials in freely moving animals. Shape and latencies of electrically evoked responses measured in the superior colliculus and visual cortex indicate that specific physiological responses could be recorded after tACS. CONCLUSIONS Our setup allows the stimulation of the visual system in unanaesthetised rodents with flicker light and transcorneally applied current travelling along the physiological signalling pathway. This methodology provides the experimental basis for further studies of recovery and restoration of vision.
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Affiliation(s)
- Elena G Sergeeva
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Petra Henrich-Noack
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | | | - Bernhard A Sabel
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
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Wu JF, Wang HJ, Wu Y, Li F, Bai YL, Zhang PY, Chan CCH. Efficacy of transcranial alternating current stimulation over bilateral mastoids (tACS bm) on enhancing recovery of subacute post-stroke patients. Top Stroke Rehabil 2016; 23:420-429. [PMID: 27145292 DOI: 10.1080/10749357.2016.1175218] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND AND AIMS Transcranial alternating current stimulation (tACS) offers another method of non-invasive brain stimulation in post-stroke rehabilitation. Because it is not known if tACS over bilateral mastoids (tACSbm) can promote the functional recovery in subacute post-stroke patients, we wish to learn the effect of tACSbm on improving neurological function and intracranial hemodynamics of subacute post-stroke patients. METHODS Sixty subacute post-stroke patients (mean age: 65.4 ± 9.8 years), 15 to 60 days after the onset, were randomly assigned to receiving 15 sessions of usual rehabilitation program without (n = 30) or with tACSbm (20 Hz and < 400 μA for 30-min; n = 30). The outcome measures included the NIH Stroke Scale (NIHSS) and measures of intracranial hemodynamics before and after treatment. RESULTS At the fifteenth session, when compared with the baseline, the mean NIHSS scores of the patients in the tACSbm group had significantly a larger decrease [18.3 ± 2.6 vs. 10.8 ± 2.7; p < 0.001] than that of the control group [19.1 ± 2.7 vs. 13.0 ± 2.4] [F(1,54) = 4.29, p = 0.043]. After both the first and fifteenth sessions, compared with the control group, the mean blood flow velocity (MFVs) of the tACSbm group had significantly larger increase in the MCA, ACA, and PCA (p < 0.001), the Gosling pulsatility index (PI) of the tACSbm group had also significantly larger decline in the MCA, ACA, and PCA than that of the control group (p < 0.001). The best predictor of the changes in the NIHSS scores was the decline in the pulsatility index in the vascular territory of both lesional and non-lesional MCA measured by the end of the last treatment session. CONCLUSIONS tACSbm appeared to be effective for enhancing patients' functional recovery and cerebral hemodynamics in the subacute phase. The extent of recovery seems to be associated with the decline of the resistance in vascular bed of the main cerebral arteries. The mechanisms behind this effect should be explored further through research.
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Affiliation(s)
- Jun-Fa Wu
- a Department of Rehabilitation Medicine, Huashan Hospital , Fudan University , Shanghai , China
| | - Hai-Jue Wang
- a Department of Rehabilitation Medicine, Huashan Hospital , Fudan University , Shanghai , China
| | - Yi Wu
- a Department of Rehabilitation Medicine, Huashan Hospital , Fudan University , Shanghai , China.,b State Key Laboratory of Medical Neurobiology , Fudan University , Shanghai , China
| | - Fang Li
- a Department of Rehabilitation Medicine, Huashan Hospital , Fudan University , Shanghai , China
| | - Yu-Long Bai
- a Department of Rehabilitation Medicine, Huashan Hospital , Fudan University , Shanghai , China
| | - Peng-Yu Zhang
- a Department of Rehabilitation Medicine, Huashan Hospital , Fudan University , Shanghai , China
| | - Chetwyn C H Chan
- c Applied Cognitive Neuroscience Laboratory, Department of Rehabilitation Sciences , The Hong Kong Polytechnic University , Hong Kong , China
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Feurra M, Galli G, Pavone EF, Rossi A, Rossi S. Frequency-specific insight into short-term memory capacity. J Neurophysiol 2016; 116:153-8. [PMID: 27121583 DOI: 10.1152/jn.01080.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 04/17/2016] [Indexed: 11/22/2022] Open
Abstract
The digit span is one of the most widely used memory tests in clinical and experimental neuropsychology for reliably measuring short-term memory capacity. In the forward version, sequences of digits of increasing length have to be reproduced in the order in which they are presented, whereas in the backward version items must be reproduced in the reversed order. Here, we assessed whether transcranial alternating current stimulation (tACS) increases the memory span for digits of young and midlife adults. Imperceptibly weak electrical currents in the alpha (10 Hz), beta (20 Hz), theta (5 Hz), and gamma (40 Hz) range, as well as a sham stimulation, were delivered over the left posterior parietal cortex, a cortical region thought to sustain maintenance processes in short-term memory through oscillatory brain activity in the beta range. We showed a frequency-specific effect of beta-tACS that robustly increased the forward memory span of young, but not middle-aged, healthy individuals. The effect correlated with age: the younger the subjects, the greater the benefit arising from parietal beta stimulation. Our results provide evidence of a short-term memory capacity improvement in young adults by online frequency-specific tACS application.
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Affiliation(s)
- Matteo Feurra
- Department of Medicine, Surgery and Neuroscience, Unit of Neurology and Clinical Neurophysiology, Brain Investigation and Neuromodulation Laboratory (Si-BIN Lab), Azienda Ospedaliera Universitaria of Siena, Policlinico Le Scotte, Siena, Italy; School of Psychology, Centre for Cognition and Decision Making, National Research University Higher School of Economics, Russian Federation, Moscow, Russia;
| | - Giulia Galli
- Department of Medicine, Surgery and Neuroscience, Unit of Neurology and Clinical Neurophysiology, Brain Investigation and Neuromodulation Laboratory (Si-BIN Lab), Azienda Ospedaliera Universitaria of Siena, Policlinico Le Scotte, Siena, Italy; Department of Psychology, Faculty of Arts and Social Sciences, Kingston University, Kingston Upon Thames, United Kingdom; and
| | - Enea Francesco Pavone
- Department of Medicine, Surgery and Neuroscience, Unit of Neurology and Clinical Neurophysiology, Brain Investigation and Neuromodulation Laboratory (Si-BIN Lab), Azienda Ospedaliera Universitaria of Siena, Policlinico Le Scotte, Siena, Italy; Department of Psychology, Sapienza University of Rome, Rome, Italy
| | - Alessandro Rossi
- Department of Medicine, Surgery and Neuroscience, Unit of Neurology and Clinical Neurophysiology, Brain Investigation and Neuromodulation Laboratory (Si-BIN Lab), Azienda Ospedaliera Universitaria of Siena, Policlinico Le Scotte, Siena, Italy
| | - Simone Rossi
- Department of Medicine, Surgery and Neuroscience, Unit of Neurology and Clinical Neurophysiology, Brain Investigation and Neuromodulation Laboratory (Si-BIN Lab), Azienda Ospedaliera Universitaria of Siena, Policlinico Le Scotte, Siena, Italy
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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.
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Affiliation(s)
- Anna Wójcik-Gryciuk
- Department of Ophthalmology, MSW Hospital, Warsaw, Poland
- Department of Neurophysiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Małgorzata Skup
- Department of Neurophysiology, Nencki Institute of Experimental Biology, Warsaw, Poland
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Abd Hamid AI, Gall C, Speck O, Antal A, Sabel BA. Effects of alternating current stimulation on the healthy and diseased brain. Front Neurosci 2015; 9:391. [PMID: 26578858 PMCID: PMC4621306 DOI: 10.3389/fnins.2015.00391] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 10/06/2015] [Indexed: 12/30/2022] Open
Abstract
Cognitive and neurological dysfunctions can severely impact a patient's daily activities. In addition to medical treatment, non-invasive transcranial alternating current stimulation (tACS) has been proposed as a therapeutic technique to improve the functional state of the brain. Although during the last years tACS was applied in numerous studies to improve motor, somatosensory, visual and higher order cognitive functions, our knowledge is still limited regarding the mechanisms as to which type of ACS can affect cortical functions and altered neuronal oscillations seem to be the key mechanism. Because alternating current send pulses to the brain at predetermined frequencies, the online- and after-effects of ACS strongly depend on the stimulation parameters so that “optimal” ACS paradigms could be achieved. This is of interest not only for neuroscience research but also for clinical practice. In this study, we summarize recent findings on ACS-effects under both normal conditions and in brain diseases.
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Affiliation(s)
- Aini Ismafairus Abd Hamid
- Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke University Magdeburg Magdeburg, Germany ; Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia Kubang Kerian, Malaysia
| | - Carolin Gall
- Institute of Medical Psychology, Otto-von-Guericke University Magdeburg Magdeburg, Germany
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke University Magdeburg Magdeburg, Germany ; Leibniz Institute for Neurobiology Magdeburg, Germany ; Center for Behavioral Brain Sciences Magdeburg, Germany ; German Center for Neurodegenerative Disease (DZNE) Magdeburg, Germany
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center, Georg-August University Goettingen, Germany
| | - Bernhard A Sabel
- Institute of Medical Psychology, Otto-von-Guericke University Magdeburg Magdeburg, Germany
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Turco S, Albamonte E, Ricci D, Fortini S, Amore FM. Bernhard Sabel and 'Residual Vision Activation Theory': a History Spanning Three Decades. Multisens Res 2015; 28:309-30. [PMID: 26288902 DOI: 10.1163/22134808-00002499] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This review has the purpose of retracing the work of Professor Bernard Sabel and his group over the last 2-3 decades, in order to understand how they achieved formulation of the 'Residual Vision Activation Theory'. The methodology proposed is described, from the first studies in 1995 with High Resolution Perimetry requiring a six-months training period, to the new technologies, such as repetitive transorbital Alternating Current Stimulation, that require ten days of training. Vision restoration therapy has shown improvement in visual responses irrespective of age at the training, lesion aetiology and site of lesion. The hypothesis that visual training may induce network plasticity, improving neuronal networks in cortical and subcortical areas of both hemispheres, appears to be confirmed by recent studies including observation of the cerebral activity by fMRI and EEG. However, the results are quite variable and the mechanisms that influence cerebral activity are still unclear. The residual vision activation theory has been much criticized, both for its methodology and analysis of the results, but it gave a new impulse to the research in this area, stimulating more studies on induced cerebral plasticity.
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42
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Dundon NM, Bertini C, Làdavas E, Sabel BA, Gall C. Visual rehabilitation: visual scanning, multisensory stimulation and vision restoration trainings. Front Behav Neurosci 2015; 9:192. [PMID: 26283935 PMCID: PMC4515568 DOI: 10.3389/fnbeh.2015.00192] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 07/09/2015] [Indexed: 12/16/2022] Open
Abstract
Neuropsychological training methods of visual rehabilitation for homonymous vision loss caused by postchiasmatic damage fall into two fundamental paradigms: “compensation” and “restoration”. Existing methods can be classified into three groups: Visual Scanning Training (VST), Audio-Visual Scanning Training (AViST) and Vision Restoration Training (VRT). VST and AViST aim at compensating vision loss by training eye scanning movements, whereas VRT aims at improving lost vision by activating residual visual functions by training light detection and discrimination of visual stimuli. This review discusses the rationale underlying these paradigms and summarizes the available evidence with respect to treatment efficacy. The issues raised in our review should help guide clinical care and stimulate new ideas for future research uncovering the underlying neural correlates of the different treatment paradigms. We propose that both local “within-system” interactions (i.e., relying on plasticity within peri-lesional spared tissue) and changes in more global “between-system” networks (i.e., recruiting alternative visual pathways) contribute to both vision restoration and compensatory rehabilitation, which ultimately have implications for the rehabilitation of cognitive functions.
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Affiliation(s)
- Neil M Dundon
- Department of Psychology, University of Bologna Bologna, Italy ; Centre for Studies and Research in Cognitive Neuroscience, University of Bologna Cesena, Italy
| | - Caterina Bertini
- Department of Psychology, University of Bologna Bologna, Italy ; Centre for Studies and Research in Cognitive Neuroscience, University of Bologna Cesena, Italy
| | - Elisabetta Làdavas
- Department of Psychology, University of Bologna Bologna, Italy ; Centre for Studies and Research in Cognitive Neuroscience, University of Bologna Cesena, Italy
| | - Bernhard A Sabel
- Medical Faculty, Institute of Medical Psychology, Otto-von-Guericke University of Magdeburg Magdeburg, Germany
| | - Carolin Gall
- Medical Faculty, Institute of Medical Psychology, Otto-von-Guericke University of Magdeburg Magdeburg, Germany
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Sergeeva EG, Bola M, Wagner S, Lazik S, Voigt N, Mawrin C, Gorkin AG, Waleszczyk WJ, Sabel BA, Henrich-Noack P. Repetitive Transcorneal Alternating Current Stimulation Reduces Brain Idling State After Long-term Vision Loss. Brain Stimul 2015; 8:1065-73. [PMID: 26145756 DOI: 10.1016/j.brs.2015.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 05/14/2015] [Accepted: 06/09/2015] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Deafferentation of visual system structures following brain or optic nerve injury leaves cortical areas deprived of visual input. Deprived cortical areas have a reduced sensory information processing and are characterized with localized enhanced or synchronized rhythms believed to represent an "idling state". OBJECTIVE/HYPOTHESIS We hypothesized that cortical idling can be modified with transcorneal alternating current stimulation (tACS) known to modulate cortical oscillations and thus change the functional state of the deafferented areas. METHODS tACS was applied in rat model of severe optic nerve crush using a protocol similar to our clinical studies (200 μA, 2-8 Hz) for 5 treatment days right after the lesion and at the chronic stage (3 months later). EEG and VEP were recorded over the visual cortices. In vivo confocal neuroimaging of the retina and histology of the optic nerves were performed. RESULTS Morphological investigations showed massive retinal ganglion cells death and degeneration of the optic nerves after crush. Visual loss was associated with increased EEG spectral power and lower coherence, indicating an "idling state". Stimulation induced a significant decrease of EEG power towards normal values. These effects were especially pronounced in the chronic stage. CONCLUSION Our results suggest that alternating current injected via the eye is able to modulate visually deprived brain areas and thus reduce cortical idling.
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Affiliation(s)
- E G Sergeeva
- Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany.
| | - M Bola
- Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany
| | - S Wagner
- Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany
| | - S Lazik
- Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany
| | - N Voigt
- Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany
| | - C Mawrin
- Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Neuropathology, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - A G Gorkin
- Institute of Psychology, Russian Academy of Science, Moscow, Russia
| | - W J Waleszczyk
- Nencki Institute of Experimental Biology, Warsaw, Poland
| | - B A Sabel
- Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany
| | - P Henrich-Noack
- Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany
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Gall C, Silvennoinen K, Granata G, de Rossi F, Vecchio F, Brösel D, Bola M, Sailer M, Waleszczyk WJ, Rossini PM, Tatlisumak T, Sabel BA. Non-invasive electric current stimulation for restoration of vision after unilateral occipital stroke. Contemp Clin Trials 2015; 43:231-6. [PMID: 26072125 DOI: 10.1016/j.cct.2015.06.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 06/08/2015] [Accepted: 06/09/2015] [Indexed: 10/23/2022]
Abstract
Occipital stroke often leads to visual field loss, for which no effective treatment exists. Little is known about the potential of non-invasive electric current stimulation to ameliorate visual functions in patients suffering from unilateral occipital stroke. One reason is the traditional thinking that visual field loss after brain lesions is permanent. Since evidence is available documenting vision restoration by means of vision training or non-invasive electric current stimulation future studies should also consider investigating recovery processes after visual cortical strokes. Here, protocols of repetitive transorbital alternating current stimulation (rtACS) and transcranial direct current stimulation (tDCS) are presented and the European consortium for restoration of vision (REVIS) is introduced. Within the consortium different stimulation approaches will be applied to patients with unilateral occipital strokes resulting in homonymous hemianopic visual field defects. The aim of the study is to evaluate effects of current stimulation of the brain on vision parameters, vision-related quality of life, and physiological parameters that allow concluding about the mechanisms of vision restoration. These include EEG-spectra and coherence measures, and visual evoked potentials. The design of stimulation protocols involves an appropriate sham-stimulation condition and sufficient follow-up periods to test whether the effects are stable. This is the first application of non-invasive current stimulation for vision rehabilitation in stroke-related visual field deficits. Positive results of the trials could have far-reaching implications for clinical practice. The ability of non-invasive electrical current brain stimulation to modulate the activity of neuronal networks may have implications for stroke rehabilitation also in the visual domain.
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Affiliation(s)
- Carolin Gall
- Institute of Medical Psychology, University of Magdeburg, Medical Faculty, Magdeburg 39120, Germany.
| | - Katri Silvennoinen
- Department of Neurology, Helsinki University Central Hospital (HUCH), Helsinki 00290, Finland
| | - Giuseppe Granata
- Department of Geriatrics, Neuroscience & Orthopedics, Catholic University of Rome, Rome 00198, Italy; IRCCS S.Raffaele Pisana, Rome 00163, Italy
| | - Francesca de Rossi
- National Centre of Services and Research for the Prevention of Blindness and Rehabilitation of Low Vision Patients - IAPB, Italian Branch, Italy
| | | | - Doreen Brösel
- Institute of Medical Psychology, University of Magdeburg, Medical Faculty, Magdeburg 39120, Germany
| | - Michał Bola
- Institute of Medical Psychology, University of Magdeburg, Medical Faculty, Magdeburg 39120, Germany
| | | | - Wioletta J Waleszczyk
- Department of Neurophysiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw 02-093, Poland
| | - Paolo M Rossini
- Department of Geriatrics, Neuroscience & Orthopedics, Catholic University of Rome, Rome 00198, Italy; IRCCS S.Raffaele Pisana, Rome 00163, Italy
| | - Turgut Tatlisumak
- Department of Neurology, Helsinki University Central Hospital (HUCH), Helsinki 00290, Finland
| | - Bernhard A Sabel
- Institute of Medical Psychology, University of Magdeburg, Medical Faculty, Magdeburg 39120, Germany
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Raco V, Bauer R, Olenik M, Brkic D, Gharabaghi A. Neurosensory effects of transcranial alternating current stimulation. Brain Stimul 2014; 7:823-31. [PMID: 25442154 DOI: 10.1016/j.brs.2014.08.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 07/16/2014] [Accepted: 08/08/2014] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Electrical brain stimulation can elicit neurosensory side effects that are unrelated to the intended stimulation effects. This presents a challenge when designing studies with blinded control conditions. OBJECTIVE The aim of this research was to investigate the role of different transcranial alternating current stimulation (tACS) parameters, i.e. intensity, frequency, and electrode montage, on the probability, duration and intensity of elicited neurosensory side effects. METHODS In a first study, we examined the influence of tACS on sensations of phosphenes, dizziness, pressure, and skin sensation in fifteen healthy subjects, during 8 s of stimulation with different amplitudes (1500 μA, 1000 μA, 500 μA, 250 μA), frequencies (2 Hz, 4 Hz, 8 Hz, 16 Hz, 32 Hz, 64 Hz), and montages (F3/F4, F3/C4, F3/P4, P3/F4, P3/C4, P3/P4). In a second study, ten healthy subjects were exposed to 60 s of tACS (1000 μA, 2 Hz versus 16 Hz, F3/F4 versus P3/P4) and were asked to rate the intensity of sensations every 12 s. RESULTS The first study showed that all stimulation parameters had an influence on the probability and intensity of sensations. Phosphenes were most likely and strongest for frontal montages and higher frequencies. Dizziness was most likely and strongest for parietal montages and at stimulation frequency of 4 Hz. Skin sensations and pressure was more likely when stimulation was performed across central regions and at posterior montages, respectively. The second study also revealed that the probability and the intensity of sensations were neither modified during more extended periods of stimulation nor affected by carry-over effects. CONCLUSION We demonstrated that the strength and the likelihood of sensations elicited by tACS were specifically modulated by the stimulation parameters. The present work may therefore be instrumental in establishing effective blinding conditions for studies with tACS.
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Affiliation(s)
- Valerio Raco
- Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany; Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany
| | - Robert Bauer
- Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany; Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany
| | - Mark Olenik
- Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany; Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany
| | - Diandra Brkic
- Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany; Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany; Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany.
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Butt GF, Habib A, Mahgoub K, Sofela A, Tilley M, Guo L, Cordeiro MF. Optic nerve regeneration. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.66] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Mante A, Rönnefarth M, Bathe-Peters R, Fleischmann R, Ambrus G, Gall C, Fedorov A, Sabel B, Schmidt S. P 228. Repetitive transorbital alternating current stimulation (rtACS) alpha activity enhancement in patients with visual field deficits: a prospective, randomized, blinded, controlled, multicenter study. Clin Neurophysiol 2013. [DOI: 10.1016/j.clinph.2013.04.305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Gall C, Steger B, Koehler J, Sabel BA. Evaluation of two treatment outcome prediction models for restoration of visual fields in patients with postchiasmatic visual pathway lesions. Neuropsychologia 2013; 51:2271-80. [PMID: 23851112 DOI: 10.1016/j.neuropsychologia.2013.06.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 06/18/2013] [Accepted: 06/28/2013] [Indexed: 01/14/2023]
Abstract
Visual functions of patients with visual field defects after acquired brain injury affecting the primary visual pathway can be improved by means of vision restoration training. Since the extent of the restored visual field varies between patients, the prediction of treatment outcome and its visualization may help patients to decide for or against participating in therapies aimed at vision restoration. For this purpose, two treatment outcome prediction models were established based on either self-organizing maps (SOMs) or categorical regression (CR) to predict visual field change after intervention by several features that were hypothesized to be associated with vision restoration. Prediction was calculated for visual field changes recorded with High Resolution Perimetry (HRP). Both models revealed a similar predictive quality with the CR model being slightly more beneficial. Predictive quality of the SOM model improved when using only a small number of features that exhibited a higher association with treatment outcome than the remaining features, i.e. neighborhood activity and homogeneity within the surrounding 5° visual field of a given position, together with its residual function and distance to the scotoma border. Although both models serve their purpose, these were not able to outperform a primitive prediction rule that attests the importance of areas of residual vision, i.e. regions with partial visual field function, for vision restoration.
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Affiliation(s)
- Carolin Gall
- Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Leipziger Str. 44, Magdeburg 39120, Germany.
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Henrich-Noack P, Lazik S, Sergeeva E, Wagner S, Voigt N, Prilloff S, Fedorov A, Sabel BA. Transcorneal alternating current stimulation after severe axon damage in rats results in “long-term silent survivor” neurons. Brain Res Bull 2013; 95:7-14. [DOI: 10.1016/j.brainresbull.2013.02.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 02/05/2013] [Accepted: 02/26/2013] [Indexed: 11/25/2022]
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50
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Improvement of visual acuity after transcorneal electrical stimulation in case of Best vitelliform macular dystrophy. Graefes Arch Clin Exp Ophthalmol 2013; 251:1867-70. [DOI: 10.1007/s00417-013-2341-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 03/23/2013] [Accepted: 04/02/2013] [Indexed: 10/27/2022] Open
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