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Zhou W, Sabel BA. Vascular dysregulation in glaucoma: retinal vasoconstriction and normal neurovascular coupling in altitudinal visual field defects. EPMA J 2023; 14:87-99. [PMID: 36866155 PMCID: PMC9971397 DOI: 10.1007/s13167-023-00316-6] [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: 10/25/2022] [Accepted: 01/24/2023] [Indexed: 02/18/2023]
Abstract
Purpose Vision loss in glaucoma is not only associated with elevated intraocular pressure and neurodegeneration, but vascular dysregulation (VD) is a major factor. To optimize therapy, an improved understanding of concepts of predictive, preventive, and personalized medicine (3PM) is needed which is based on a more detailed understanding of VD pathology. Specifically, to learn if the root cause of glaucomatous vision loss is of neuronal (degeneration) or vascular origin, we now studied neurovascular coupling (NVC) and vessel morphology and their relationship to vision loss in glaucoma. Methods In patients with primary open angle glaucoma (POAG) (n = 30) and healthy controls (n = 22), NVC was studied using dynamic vessel analyzer to quantify retinal vessel diameter before, during, and after flicker light stimulation to evaluate the dilation response following neuronal activation. Vessel features and dilation were then related to branch level and visual field impairment. Results Retinal arterial and venous vessels had significantly smaller diameters in patients with POAG in comparison to controls. However, both arterial and venous dilation reached normal values during neuronal activation despite their smaller diameters. This was largely independent of visual field depth and varied among patients. Conclusions Because dilation/constriction is normal, VD in POAG can be explained by chronic vasoconstriction which limits energy supply to retinal (and brain) neurons with subsequent hypo-metabolism ("silent" neurons) or neuronal cell death. We propose that the root cause of POAG is primarily of vascular and not neuronal origin. This understanding can help to better personalize POAG therapy of not only targeting eye pressure but also vasoconstriction to prevent low vision, slowing its progression and supporting recovery and restoration. Trial registration ClinicalTrials.gov, # NCT04037384 on July 3, 2019.
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Affiliation(s)
- Wanshu Zhou
- grid.5807.a0000 0001 1018 4307Institute of Medical Psychology, Medical Faculty, Otto-Von-Guericke University of Magdeburg, Leipziger Straße 44, 39120 Magdeburg, Germany
| | - Bernhard A. Sabel
- grid.5807.a0000 0001 1018 4307Institute of Medical Psychology, Medical Faculty, Otto-Von-Guericke University of Magdeburg, Leipziger Straße 44, 39120 Magdeburg, Germany
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Halbertsma HN, Elshout JA, Bergsma DP, Norris DG, Cornelissen FW, van den Berg AV, Haak KV. Functional connectivity of the Precuneus reflects effectiveness of visual restitution training in chronic hemianopia. Neuroimage Clin 2020; 27:102292. [PMID: 32554320 PMCID: PMC7303670 DOI: 10.1016/j.nicl.2020.102292] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 04/17/2020] [Accepted: 05/19/2020] [Indexed: 01/10/2023]
Abstract
Visual field defects in chronic hemianopia can improve through visual restitution training, yet not all patients benefit equally from this long and exhaustive procedure. Here, we asked if resting-state functional connectivity prior to visual restitution could predict training success. In two training sessions of eight weeks each, 20 patients with chronic hemianopia performed a visual discrimination task by directing spatial selective attention towards stimuli presented in either hemifield, while suppressing eye movements. We examined two effects: a sensitivity change in the attended (trained) minus the unattended (control) hemifield (i.e., a training-specific improvement), and an overall improvement (i.e., a total change in sensitivity after both sessions). We then identified five visual resting-state networks and evaluated their functional connectivity in relation to both training effects. We found that the functional connectivity strength between the anterior Precuneus and the Occipital Pole Network was positively related to the attention modulated (i.e., training-specific) improvement. No such relationship was found for the overall improvement or for the other visual networks of interest. Our finding suggests that the anterior Precuneus plays a role in attention-modulated visual field improvements. The resting-state functional connectivity between the anterior Precuneus and the Occipital Pole Network may thus serve as an imaging-based biomarker that quantifies a patient's potential capacity to direct spatial attention. This may help to identify hemianopia patients that are most likely to benefit from visual restitution training.
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Affiliation(s)
- Hinke N Halbertsma
- Laboratory for Experimental Ophthalmology, University Medical Center Groningen, Groningen, the Netherlands.
| | - Joris A Elshout
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Douwe P Bergsma
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - David G Norris
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans W Cornelissen
- Laboratory for Experimental Ophthalmology, University Medical Center Groningen, Groningen, the Netherlands
| | - Albert V van den Berg
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Koen V Haak
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
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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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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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Kim BJ, Kim YH, Kim N, Kwon SU, Kim SJ, Kim JS, Kang DW. Lesion Location-Based Prediction of Visual Field Improvement after Cerebral Infarction. PLoS One 2015; 10:e0143882. [PMID: 26606516 PMCID: PMC4659640 DOI: 10.1371/journal.pone.0143882] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 11/10/2015] [Indexed: 11/18/2022] Open
Abstract
Background Although the prognosis of ischemic stroke is highly dependent on the lesion location, it has rarely been quantitatively utilized. We investigated the usefulness of regional extent of ischemic lesion (rEIL) predicting the improvement of visual field defect (VFD) in patients with posterior cerebral artery infarction. Methods The rEILs were measured in each individual cortex after transforming the lesions to a standard atlas. Significant improvement of VFD was tentatively defined as 20% improvement at 3 months after stroke. The performances of clinical and imaging variables predicting significant improvement were measured by support vector machine. The maximum performance of variables predicting the significant improvement was compared between subgroups of variables (clinical, baseline severity and lesion volume) and the effect of adding rEIL to those subgroups of variables was evaluated. Results A total of 35 patients were enrolled in this study. Left PCA infarct, MR-time from onset, rEILs in the lingual, calcarine, and cuneus cortices were good prognostic indicators of hemi-VFD (performance for predicting the significant improvement: 72.8±11.8%, 66.1±11.2%, respectively). A combination of the rEILs of each cortical subregions demonstrated a better predictive performance for hemi-VFD (83.8±9.5%) compared to a combination of clinical variables (72.8±11.8; p<0.001), baseline severity (63.0±11.9%; p<0.001), or lesion volume (62.6±12.7%; p<0.001). Adding a rEIL to other variables improved the prognostic prediction for hemi-VFD (74.4±11.6% to 91.3±7.7%; p<0.001). Conclusions An estimation of rEIL provides useful information regarding the ischemic lesion location. rEIL accurately predicts the significant improvement of VFD and enhances the prediction power when combined with other variables.
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Affiliation(s)
- Bum Joon Kim
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Seoul Korea
| | - Yong-Hwan Kim
- Vision, Image and Learning Laboratory, Asan Institute for Life Sciences, Asan Medical Center, Seoul, South Korea
| | - Namkug Kim
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Seoul Korea
- Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Seoul Korea
| | - Sun U. Kwon
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Seoul Korea
| | - Sang Joon Kim
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Seoul Korea
| | - Jong S. Kim
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Seoul Korea
| | - Dong-Wha Kang
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Seoul Korea
- Vision, Image and Learning Laboratory, Asan Institute for Life Sciences, Asan Medical Center, Seoul, South Korea
- * E-mail:
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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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Pouget MC, Lévy-Bencheton D, Prost M, Tilikete C, Husain M, Jacquin-Courtois S. Acquired visual field defects rehabilitation: Critical review and perspectives. Ann Phys Rehabil Med 2012; 55:53-74. [DOI: 10.1016/j.rehab.2011.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 04/28/2011] [Accepted: 05/01/2011] [Indexed: 10/14/2022]
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Fedorov A, Jobke S, Bersnev V, Chibisova A, Chibisova Y, Gall C, Sabel BA. Restoration of vision after optic nerve lesions with noninvasive transorbital alternating current stimulation: a clinical observational study. Brain Stimul 2011; 4:189-201. [PMID: 21981854 DOI: 10.1016/j.brs.2011.07.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 07/11/2011] [Accepted: 07/12/2011] [Indexed: 10/16/2022] Open
Abstract
BACKGROUND Non-invasive current stimulation can induce neuroplastic changes in the normal brain, including visual system structures. Because it is not known if such plasticity is of clinical value, we wished to learn if vision restoration can be induced after optic nerve damage. METHODS In an open-label, clinical observational study 446 patients with optic nerve lesions were treated with non-invasive repetitive transorbital alternating current stimulation (rtACS). Current bursts (<1000 μA, 5-20 Hz) were applied to induce phosphenes for one or two 10-day stimulation periods. Efficacy was assessed by monocular measurements of visual acuity and visual field (VF) size. EEG recordings at rest (n = 68) were made before and after treatment and global power spectra changes were analyzed. RESULTS rtACS improved VF size in the right and left eye by 7.1% and 9.3% (p < 0.001), respectively. VF enlargements were present in 40.4% of right and 49.5% of left eyes. Visual acuity (VA) significantly increased in both eyes (right = 0.02, left = 0.015; p < 0.001). A second 10-day course was conducted 6 months in a subset of 62 patients and resulted in additional significant improvements of VA. Analysis of EEG power spectra revealed that VA and VF improvements were associated with increased alpha power. Increased theta power was observed in patients that had only VF enlargements but no VA change. In contrast, non-responders had increased delta power spectra in frontal and occipital areas. CONCLUSIONS rtACS leads to long-lasting improvements in VA and VF size and after-effects in EEG power spectra. Because physiological and clinical parameters are correlated we hypothesize that rtACS enhances plasticity by inducing synchronization in different cortical regions, but the precise mechanisms needs further clarification. These encouraging results require confirmation by controlled clinical trials.
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Affiliation(s)
- A Fedorov
- Polenov Russian Neurosurgical Institute, Saint-Petersburg, Russia.
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Vision restoration after brain and retina damage: the "residual vision activation theory". PROGRESS IN BRAIN RESEARCH 2011; 192:199-262. [PMID: 21763527 DOI: 10.1016/b978-0-444-53355-5.00013-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vision loss after retinal or cerebral visual injury (CVI) was long considered to be irreversible. However, there is considerable potential for vision restoration and recovery even in adulthood. Here, we propose the "residual vision activation theory" of how visual functions can be reactivated and restored. CVI is usually not complete, but some structures are typically spared by the damage. They include (i) areas of partial damage at the visual field border, (ii) "islands" of surviving tissue inside the blind field, (iii) extrastriate pathways unaffected by the damage, and (iv) downstream, higher-level neuronal networks. However, residual structures have a triple handicap to be fully functional: (i) fewer neurons, (ii) lack of sufficient attentional resources because of the dominant intact hemisphere caused by excitation/inhibition dysbalance, and (iii) disturbance in their temporal processing. Because of this resulting activation loss, residual structures are unable to contribute much to everyday vision, and their "non-use" further impairs synaptic strength. However, residual structures can be reactivated by engaging them in repetitive stimulation by different means: (i) visual experience, (ii) visual training, or (iii) noninvasive electrical brain current stimulation. These methods lead to strengthening of synaptic transmission and synchronization of partially damaged structures (within-systems plasticity) and downstream neuronal networks (network plasticity). Just as in normal perceptual learning, synaptic plasticity can improve vision and lead to vision restoration. This can be induced at any time after the lesion, at all ages and in all types of visual field impairments after retinal or brain damage (stroke, neurotrauma, glaucoma, amblyopia, age-related macular degeneration). If and to what extent vision restoration can be achieved is a function of the amount of residual tissue and its activation state. However, sustained improvements require repetitive stimulation which, depending on the method, may take days (noninvasive brain stimulation) or months (behavioral training). By becoming again engaged in everyday vision, (re)activation of areas of residual vision outlasts the stimulation period, thus contributing to lasting vision restoration and improvements in quality of life.
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