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Sezai T, Murphy MJ, Riddell N, Nguyen V, Crewther SG. Visual Processing During the Interictal Period Between Migraines: A Meta-Analysis. Neuropsychol Rev 2023; 33:765-782. [PMID: 36115887 PMCID: PMC10770263 DOI: 10.1007/s11065-022-09562-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 07/20/2022] [Indexed: 10/14/2022]
Abstract
Migraine is a poorly understood neurological disorder and a leading cause of disability in young adults, particularly women. Migraines are characterized by recurring episodes of severe pulsating unilateral headache and usually visual symptoms. Currently there is some disagreement in the electrophysiological literature regarding the universality of all migraineurs exhibiting physiological visual impairments also during interictal periods (i.e., the symptom free period between migraines). Thus, this meta-analysis investigated the evidence for altered visual function as measured electrophysiologically via pattern-reversal visual evoked potential (VEP) amplitudes and habituation in adult migraineurs with or without visual aura and controls in the interictal period. Twenty-three studies were selected for random effects meta-analysis which demonstrated slightly diminished VEP amplitudes in the early fast conducting P100 component but not in N135, and substantially reduced habituation in the P100 and the N135 in migraineurs with and without visual aura symptoms compared to controls. No statistical differences were found between migraineurs with and without aura, possibly due to inadequate studies. Overall, insufficient published data and substantial heterogeneity between studies was observed for all latency components of pattern-reversal VEP, highlighting the need for further electrophysiological experimentation and more targeted temporal analysis of visual function, in episodic migraineurs.
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Affiliation(s)
- Timucin Sezai
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Melanie J Murphy
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Nina Riddell
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Vinh Nguyen
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Sheila G Crewther
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, 3086, Australia.
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Alshamrani FJ, AlSheikh MH, Almuslim N, Al Azman H, Alkhamis F, Nazish S, Alnajashi H, Alsulaiman A. Prospective Matched Case-Control Study of Over-Early P100 Wave Latency in Migraine with Aura. Biomedicines 2023; 11:2979. [PMID: 38001979 PMCID: PMC10669729 DOI: 10.3390/biomedicines11112979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/19/2023] [Accepted: 10/28/2023] [Indexed: 11/26/2023] Open
Abstract
A sizable portion of the world's population suffers from migraines with aura. The purpose of this research is to describe the findings of a case-control study that was carried out to gain a better understanding of how migraine with aura manifests. The research looked at the P100 delay of the visual-evoked potential in both eyes of 92 healthy people and 44 patients who suffered from migraines with visual aura. All of the participants in the study were recruited from King Fahad University Hospital in Saudi Arabia. Both sets of people had the same ancestry and originated from the same location. Patients who suffered from migraines with aura exhibited a significantly shorter P100 delay in both eyes compared to healthy controls (p = 0.001), which is evidence that their early visual processing was distinct. In order to arrive at these findings, we compared people who suffer from migraines with aura to people who do not suffer from migraines and used them as subjects. These findings contribute to the ongoing attempts to bring the disease under control and provide vitally significant new information regarding the functioning of headaches with auras. The primary focus of study in the future should be on determining the nature of the connection between issues with early visual processing and headaches with aura.
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Affiliation(s)
- Foziah J. Alshamrani
- Department of Neurology, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 34212, Saudi Arabia (S.N.)
| | - Mona Hmoud AlSheikh
- Physiology Department, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 34212, Saudi Arabia;
| | - Noora Almuslim
- Neurology Department, King Fahad University Hospital, Dammam, Imam Abdulrahman Bin Faisal University, Dammam 34212, Saudi Arabia
| | - Hatem Al Azman
- Neurology Department, King Fahad University Hospital, Dammam, Imam Abdulrahman Bin Faisal University, Dammam 34212, Saudi Arabia
| | - Fahad Alkhamis
- Department of Neurology, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 34212, Saudi Arabia (S.N.)
| | - Saima Nazish
- Department of Neurology, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 34212, Saudi Arabia (S.N.)
| | - Hind Alnajashi
- Neurology Division, Department of Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
| | - Abdulla Alsulaiman
- Department of Neurology, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 34212, Saudi Arabia (S.N.)
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Brooks CJ, Chan YM, Fielding J, White OB, Badcock DR, McKendrick AM. Visual contrast perception in visual snow syndrome reveals abnormal neural gain but not neural noise. Brain 2021; 145:1486-1498. [PMID: 34633444 DOI: 10.1093/brain/awab383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 09/17/2021] [Accepted: 09/21/2021] [Indexed: 11/14/2022] Open
Abstract
Visual snow syndrome is a neurological condition characterised by a persistent visual disturbance, visual snow, in conjunction with additional visual symptoms. Cortical hyperexcitability is a potential pathophysiological mechanism, which could be explained by increased gain in neural responses to visual input. Alternatively, neural noise in the visual pathway could be abnormally elevated. We assessed these two potential competing neural mechanisms in our studies of visual contrast perception. Cortical hyperexcitation also occurs in migraine, which commonly co-occurs with visual snow syndrome. Therefore, to determine whether the effect of visual snow syndrome can be distinguished from interictal migraine, we recruited four participant groups: controls, migraine alone, visual snow syndrome alone, visual snow syndrome with migraine. In the first experiment, we estimated internal noise in 20 controls, 21 migraine participants, 32 visual snow syndrome participants (16 with migraine) using a luminance increment detection task. In the second experiment, we estimated neural contrast gain in 21 controls, 22 migraine participants, 35 visual snow syndrome participants (16 with migraine) using tasks assessing sensitivity to changes in contrast from a reference. Contrast gain and sensitivity were measured for the putative parvocellular and ON and OFF magnocellular pathways, respectively. We found that luminance increment thresholds and internal noise estimates were normal in both visual snow syndrome and migraine. Contrast gain measures for putative parvocellular processing and contrast sensitivity for putative OFF magnocellular processing were abnormally increased in visual snow syndrome, regardless of migraine status. Therefore, our results indicate that visual snow syndrome is characterised by increased neural contrast gain but not abnormal neural noise within the targeted pathways.
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Affiliation(s)
- Cassandra J Brooks
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Australia
| | - Yu Man Chan
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Australia
| | - Joanne Fielding
- Department of Neurosciences, Central Clinical School, Monash University, Melbourne, Australia
| | - Owen B White
- Department of Neurosciences, Central Clinical School, Monash University, Melbourne, Australia
| | - David R Badcock
- School of Psychological Science, The University of Western Australia, Crawley, Western Australia
| | - Allison M McKendrick
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Australia
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McKendrick AM, Nguyen BN. The eye in migraine: a review of retinal imaging findings in migraine. Clin Exp Optom 2021; 105:186-193. [PMID: 34538219 DOI: 10.1080/08164622.2021.1971045] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Migraine is a common headache disorder with neurovascular involvement. Because eyecare practitioners are likely to encounter people with migraine in their everyday practice, it is important to understand how migraine might impact on ocular health. In this narrative review, we provide an update on the latest ophthalmic imaging evidence for retinal involvement in migraine, derived from studies of retinal structure and retinal vascular perfusion using spectral domain and swept source optical coherence tomography (OCT) and OCT angiography. Combined structural OCT evidence from a recent meta-analysis indicates subtle and non-specific thinning of the peripapillary retinal nerve fibre layer (RNFL) in people with migraine, whereas there is little consistent evidence for structural abnormalities of the macular region. Recent advances in OCT angiography technology have also provided an opportunity to visualise microstructural damage and vascular dysregulation in the eyes of people with migraine. However, given that OCT and OCT angiography studies have been exclusively cross-sectional, it is not possible to demonstrate the causal effect of migraine events. Furthermore, the lack of common methodology (different ophthalmic imaging devices and analysis algorithms), and very limited datasets (small samples, heterogenous migraine groups), lead to an inability to make strong conclusions regarding the nature of altered retinal structure and vascular perfusion in migraine. Nevertheless, we discuss the clinical implications of such observations for eyecare practitioners and provide practical advice for the monitoring and management of patients with a history of migraine.
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Affiliation(s)
- Allison M McKendrick
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Bao N Nguyen
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
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O’Hare L, Asher JM, Hibbard PB. Migraine Visual Aura and Cortical Spreading Depression-Linking Mathematical Models to Empirical Evidence. Vision (Basel) 2021; 5:30. [PMID: 34200625 PMCID: PMC8293461 DOI: 10.3390/vision5020030] [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: 03/25/2021] [Revised: 05/15/2021] [Accepted: 05/24/2021] [Indexed: 01/10/2023] Open
Abstract
This review describes the subjective experience of visual aura in migraine, outlines theoretical models of this phenomenon, and explores how these may be linked to neurochemical, electrophysiological, and psychophysical differences in sensory processing that have been reported in migraine with aura. Reaction-diffusion models have been used to model the hallucinations thought to arise from cortical spreading depolarisation and depression in migraine aura. One aim of this review is to make the underlying principles of these models accessible to a general readership. Cortical spreading depolarisation and depression in these models depends on the balance of the diffusion rate between excitation and inhibition and the occurrence of a large spike in activity to initiate spontaneous pattern formation. We review experimental evidence, including recordings of brain activity made during the aura and attack phase, self-reported triggers of migraine, and psychophysical studies of visual processing in migraine with aura, and how these might relate to mechanisms of excitability that make some people susceptible to aura. Increased cortical excitability, increased neural noise, and fluctuations in oscillatory activity across the migraine cycle are all factors that are likely to contribute to the occurrence of migraine aura. There remain many outstanding questions relating to the current limitations of both models and experimental evidence. Nevertheless, reaction-diffusion models, by providing an integrative theoretical framework, support the generation of testable experimental hypotheses to guide future research.
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Affiliation(s)
- Louise O’Hare
- Division of Psychology, Nottingham Trent University, Nottingham NG1 4FQ, UK
| | - Jordi M. Asher
- Department of Psychology, University of Essex, Colchester CO4 3SQ, UK; (J.M.A.); (P.B.H.)
| | - Paul B. Hibbard
- Department of Psychology, University of Essex, Colchester CO4 3SQ, UK; (J.M.A.); (P.B.H.)
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6
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Gedde SJ, Vinod K, Wright MM, Muir KW, Lind JT, Chen PP, Li T, Mansberger SL. Primary Open-Angle Glaucoma Preferred Practice Pattern®. Ophthalmology 2021; 128:P71-P150. [DOI: 10.1016/j.ophtha.2020.10.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 12/17/2022] Open
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Dehghan A, Saatchian E, Sobhani M, Montazerabadi A. Neurochemical metabolite alterations of the occipital lobe in migraine without aura by proton magnetic resonance spectroscopy. Neuroradiol J 2020; 33:410-415. [PMID: 32573358 PMCID: PMC7482038 DOI: 10.1177/1971400920932793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Migraine without aura is the most common type of migraine headache, accounting for about 80% of all migraines. The aim of the present investigation was to determine the neurochemical metabolite alterations in the occipital lobe of patients suffering from migraine without aura using proton magnetic resonance spectroscopy (1H-MRS). METHODS Fifteen patients suffering from migraine without aura with an occipital plaque and 16 healthy controls were included in this study. Changes in the neurochemical metabolites in the occipital lobe were assessed using 1H-MRS. The ratios of N-acetylaspartate (NAA) to creatine (Cr), choline (Cho) to Cr and myo-inositol (MI) to NAA were measured by voxel volume at 8 cm3. RESULTS The mean NAA/Cr ratio decreased significantly in patients compared to controls. Cho/Cr and MI/NAA ratios increased significantly in patients. In addition, the duration of the disease and the frequency of headache attacks were significantly associated with a decrease in the NAA/Cr ratio and an increase in the Cho/Cr ratio. CONCLUSIONS Migraine without aura shows a significant association with changes in neurochemical metabolites detectable by 1H-MRS in the occipital lobe of patients. In addition, changes in metabolic ratios showed a significant relationship with the duration of the disease and the frequency of headache attacks.
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Affiliation(s)
- Alireza Dehghan
- Medical Physics Research Centre, Mashhad University of Medical Sciences, Iran
| | - Erfan Saatchian
- Medical Physics Research Centre, Mashhad University of Medical Sciences, Iran
| | - Mohammadreza Sobhani
- Neurology Department, Faculty of Medicine, Gonabad University of Medical Sciences, Iran
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Coppola G, Parisi V, Di Renzo A, Pierelli F. Cortical pain processing in migraine. J Neural Transm (Vienna) 2019; 127:551-566. [DOI: 10.1007/s00702-019-02089-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 09/28/2019] [Indexed: 12/17/2022]
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O'Hare L. Temporal Integration of Motion Streaks in Migraine. Vision (Basel) 2018; 2:E27. [PMID: 31735890 PMCID: PMC6836222 DOI: 10.3390/vision2030027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/11/2018] [Accepted: 07/11/2018] [Indexed: 11/16/2022] Open
Abstract
Migraine is associated with differences in visual perception, specifically, deficits in the perception of motion. Migraine groups commonly show poorer performance (higher thresholds) on global motion tasks compared to control groups. Successful performance on a global motion task depends on several factors, including integrating signals over time. A "motion streak" task was used to investigate specifically integration over time in migraine and control groups. The motion streak effect depends on the integration of a moving point over time to create the illusion of a line, or "streak". There was evidence of a slower optimum speed for eliciting the motion streak effect in migraine compared to control groups, suggesting temporal integration is different in migraine. In addition, performance on the motion streak task showed a relationship with headache frequency.
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Affiliation(s)
- Louise O'Hare
- School of Psychology, University of Lincoln, Lincoln LN6 7TS, UK
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10
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McKendrick AM, Chan YM, Vingrys AJ, Turpin A, Badcock DR. Daily vision testing can expose the prodromal phase of migraine. Cephalalgia 2017; 38:1575-1584. [DOI: 10.1177/0333102417741130] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Background Several visual tasks have been proposed as indirect assays of the balance between cortical inhibition and excitation in migraine. This study aimed to determine whether daily measurement of performance on such tasks can reveal perceptual changes in the build up to migraine events. Methods Visual performance was measured daily at home in 16 non-headache controls and 18 individuals with migraine using a testing protocol on a portable tablet device. Observers performed two tasks: luminance increment detection in spatial luminance noise and centre surround contrast suppression. Results Luminance thresholds were reduced in migraine compared to control groups ( p < 0.05), but thresholds did not alter across the migraine cycle; while headache-free, centre-surround contrast suppression was stronger for the migraine group relative to controls ( p < 0.05). Surround suppression weakened at around 48 hours prior to a migraine attack and strengthened to approach their headache-free levels by 24 hours post-migraine (main effect of timing, p < 0.05). Conclusions Daily portable testing of vision enabled insight into perceptual performance in the lead up to migraine events, a time point that is typically difficult to capture experimentally. Perceptual surround suppression of contrast fluctuates during the migraine cycle, supporting the utility of this measure as an indirect, non-invasive assay of the balance between cortical inhibition and excitation.
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Affiliation(s)
- Allison M McKendrick
- University of Melbourne, Department of Optometry and Vision Sciences, Melbourne, Australia
| | - Yu Man Chan
- University of Melbourne, Department of Optometry and Vision Sciences, Melbourne, Australia
| | - Algis J Vingrys
- University of Melbourne, Department of Optometry and Vision Sciences, Melbourne, Australia
| | - Andrew Turpin
- University of Melbourne, Department of Computing and Information System, Melbourne, Australia
| | - David R Badcock
- University of Western Australia, School of Psychological Science, Perth, Australia
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11
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Ophthalmological Assessment of OCT and Electrophysiological Changes in Migraine Patients. J Clin Neurophysiol 2016; 33:431-442. [PMID: 26840983 DOI: 10.1097/wnp.0000000000000256] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND A cross-sectional study to investigate the morphological and functional changes of the visual pathway taking place in patients with migraine. METHODS Fifteen patients (14 female, 1 male) diagnosed with migraine with aura and 23 patients (21 female, 2 male) diagnosed with migraine without aura were compared with 20 healthy volunteers (18 female, 2 male). All the participants underwent optical coherence tomography scan, electroretinogram (ERG), visual evoked potentials, and multifocal electroretinogram (mf-ERG) recording. RESULTS Assessing ERG recordings, no significant differences in mean N1-P1 amplitudes were measured among the groups. The mean visual evoked potentials N80-P100 amplitudes were not significantly different among the three groups (one way analysis of variance: P = 0.075, F = 2.718). No significant difference was found in P100 latency times among groups. The mean retinal response density of mf-ERG in ring 1 was higher in healthy individuals compared with migraineurs, with statistical significance (Kruskal-Wallis analysis of variance and Dunn multiple comparisons test; P < 0.001, mean rank difference = -24.857 and P < 0.001, mean rank difference = -20.9, for migraine with aura-control and migraine without aura-control comparisons, respectively). In migraine with aura subjects, retinal nerve fiber layer thickness in superior and inferior quadrants was significantly decreased compared with healthy individuals, whereas in migraine without aura group, only the superior quadrant was significantly thinner compared with the control group. CONCLUSIONS Retinal response density in mfERG of all migraineurs was significantly lessened compared with healthy individuals. There was no significant difference in visual evoked potentials N80-P100 amplitudes or P100 latencies among the groups. Moreover, retinal nerve fiber layer thinning observed in patients with migraine compared with control subjects, appeared statistically significant in some quadrants. The authors may be able to defend the retinal blood flow decrease theory in migraine. The results also indicate that several levels of the visual pathway seem to be affected in migraineurs.
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Abstract
Background Migraine is a common neurological condition that often involves differences in visual processing. These sensory processing differences provide important information about the underlying causes of the condition, and for the development of treatments. Review of psychophysical literature Psychophysical experiments have shown consistent impairments in contrast sensitivity, orientation acuity, and the perception of global form and motion. They have also established that the addition of task-irrelevant visual noise has a greater effect, and that surround suppression, masking and adaptation are all stronger in migraine. Theoretical signal processing model We propose utilising an established model of visual processing, based on signal processing theory, to account for the behavioural differences seen in migraine. This has the advantage of precision and clarity, and generating clear, falsifiable predictions. Conclusion Increased effects of noise and differences in excitation and inhibition can account for the differences in migraine visual perception. Consolidating existing research and creating a unified, defined theoretical account is needed to better understand the disorder.
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Affiliation(s)
- Louise O'Hare
- School of Psychology, College of Social Science, University of Lincoln, UK
| | - Paul B Hibbard
- Department of Psychology, University of Essex, UK
- School of Psychology and Neuroscience, University of St Andrews, UK
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14
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Yohannan J, Jampel H. Progressing Scintillating Scotoma Captured on Automated Visual Field Testing. Ophthalmology 2016; 123:1395-6. [DOI: 10.1016/j.ophtha.2016.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 01/04/2016] [Accepted: 01/05/2016] [Indexed: 10/22/2022] Open
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Nguyen BN, Lek JJ, Vingrys AJ, McKendrick AM. Clinical impact of migraine for the management of glaucoma patients. Prog Retin Eye Res 2015; 51:107-24. [PMID: 26232725 DOI: 10.1016/j.preteyeres.2015.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/23/2015] [Accepted: 07/27/2015] [Indexed: 12/19/2022]
Abstract
Migraine is a common and debilitating primary headache disorder that affects 10-15% of the general population, particularly people of working age. Migraine is relevant to providers of clinical eye-care because migraine attacks are associated with a range of visual sensory symptoms, and because of growing evidence that the results of standard tests of visual function necessary for the diagnosis and monitoring of glaucoma (visual fields, electrophysiology, ocular imaging) can be abnormal due to migraine. These abnormalities are measureable in-between migraine events (the interictal period), despite patients being asymptomatic and otherwise healthy. This picture is further complicated by epidemiological data that suggests an increased prevalence of migraine in patients with glaucoma, particularly in patients with normal tension glaucoma. We discuss how migraine, as a co-morbidity, can confound the results and interpretation of clinical tests that form part of contemporary glaucoma evaluation, and provide practical evidence-based recommendations for the clinical testing and management of patients with migraine who attend eye-care settings.
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Affiliation(s)
- Bao N Nguyen
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia.
| | - Jia Jia Lek
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Algis J Vingrys
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Allison M McKendrick
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
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Ballae Ganeshrao S, Turpin A, Denniss J, McKendrick AM. Enhancing Structure-Function Correlations in Glaucoma with Customized Spatial Mapping. Ophthalmology 2015; 122:1695-705. [PMID: 26077579 DOI: 10.1016/j.ophtha.2015.04.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 04/13/2015] [Accepted: 04/16/2015] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To determine whether the structure-function relationship in glaucoma can be strengthened by using more precise structural and functional measurements combined with individualized structure-function maps and custom sector selection on the optic nerve head (ONH). DESIGN Cross-sectional study. PARTICIPANTS One eye of each of 23 participants with glaucoma. METHODS Participants were tested twice. Visual fields were collected on a high-resolution 3° × 3° grid (164 locations) using a Zippy Estimation by Sequential Testing test procedure with uniform prior probability to improve the accuracy and precision of scotoma characterization relative to standard methods. Retinal nerve fiber layer (RNFL) thickness was measured using spectral-domain optical coherence tomography (OCT; 4 scans, 2 per visit) with manual removal of blood vessels. Individualized maps, based on biometric data, were used. To customize the areas of the ONH and visual field to correlate, we chose a 30° sector centered on the largest defect shown by OCT and chose visual field locations using the individualized maps. Baseline structure-function correlations were calculated between 24-2 locations (n = 52) of the first tested visual field and RNFL thickness from 1 OCT scan, using the sectors of the Garway-Heath map. We added additional data (averaged visual field and OCT, additional 106 visual field locations and OCT without blood vessels, individualized map, and customized sector) and recomputed the correlations. MAIN OUTCOME MEASURES Spearman correlation between structure and function. RESULTS The highest baseline correlation was 0.52 (95% confidence interval [CI], 0.13-0.78) in the superior temporal ONH sector. Improved measurements increased the correlation marginally to 0.58 (95% CI, 0.21-0.81). Applying the individualized map to the large, predefined ONH sectors did not improve the correlation; however, using the individualized map with the single 30° ONH sector resulted in a large increase in correlation to 0.77 (95% CI, 0.47-0.92). CONCLUSIONS Using more precise visual field and OCT measurements did not improve structure-function correlation in our cohort, but customizing the ONH sector and its associated visual field points substantially improved correlation. We suggest using customized ONH sectors mapped to individually relevant visual field locations to unmask localized structural and functional loss.
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Affiliation(s)
- Shonraj Ballae Ganeshrao
- Department of Computing and Information Systems, University of Melbourne, Melbourne, Australia; Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Australia
| | - Andrew Turpin
- Department of Computing and Information Systems, University of Melbourne, Melbourne, Australia
| | - Jonathan Denniss
- Department of Computing and Information Systems, University of Melbourne, Melbourne, Australia; Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Australia; Visual Neuroscience Group, School of Psychology, University of Nottingham, Nottingham, United Kingdom
| | - Allison M McKendrick
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Australia.
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Nguyen BN, McKendrick AM, Vingrys AJ. Abnormal inhibition-excitation imbalance in migraine. Cephalalgia 2015; 36:5-14. [DOI: 10.1177/0333102415576725] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 02/02/2015] [Indexed: 12/17/2022]
Abstract
Background People with migraine show increased surround suppression of perceived contrast, a perceptual analogue of centre-surround antagonistic interactions in visual cortex. A proposed mechanism is that cortical ‘hyperexcitability’ or ‘hyperresponsivity’, a prominent theory in the migraine literature, drives abnormal excitatory-inhibitory balance to give increased local inhibition. The purpose of this cross-sectional study was to determine whether cortical hyperresponsivity and excitatory-inhibitory imbalance manifests in the visual cortical response of migraine sufferers. Methods Interictal steady-state visual evoked potentials (VEPs) in response to 0 to 97% contrast were recorded in 30 migraine participants (15 without aura, 15 with aura) and 21 non-headache controls. Monotonicity indices were calculated to determine response saturation or supersaturation. Contrast gain was modelled with a modified saturating hyperbolic function to allow for variation in excitation and inhibition. Results A greater proportion of migraine participants (43%) than controls (14%) exhibited significant VEP supersaturation at high contrast, based on monotonicity index (chi-square, p = 0.028). Supersaturation was also evident by the trend for greater suppressive exponent values in migraine compared to control individuals (Mann-Whitney rank sum, p = 0.075). Conclusions Supersaturation in migraine is consistent with excess excitation (hyperresponsivity) driving increased network inhibition and provides support for excitatory-inhibitory imbalance as a pathophysiological disturbance in migraine.
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Affiliation(s)
- Bao N Nguyen
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Allison M McKendrick
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Algis J Vingrys
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
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