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Visual Evoked Potentials as a Biomarker in Multiple Sclerosis and Associated Optic Neuritis. J Neuroophthalmol 2020; 38:350-357. [PMID: 30106802 DOI: 10.1097/wno.0000000000000704] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
: ABSTRACT:: Multiple sclerosis (MS) is an inflammatory, degenerative disease of the central nervous system (CNS) characterized by progressive neurological decline over time. The need for better "biomarkers" to more precisely capture and track the effects of demyelination, remyelination, and associated neuroaxonal injury is a well-recognized challenge in the field of MS. To this end, visual evoked potentials (VEPs) have a role in assessing the extent of demyelination along the optic nerve, as a functionally eloquent CNS region. Moreover, VEPs testing can be used to predict the extent of recovery after optic neuritis (ON) and capture disabling effects of clinical and subclinical demyelination events in the afferent visual pathway. In this review, the evolving role of VEPs in the diagnosis of patients with ON and MS and the utility of VEPs testing in determining therapeutic benefits of emerging MS treatments is discussed.
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Behbehani R, Ali A, Al-Omairah H, Rousseff RT. Optimization of spectral domain optical coherence tomography and visual evoked potentials to identify unilateral optic neuritis. Mult Scler Relat Disord 2020; 41:101988. [PMID: 32092503 DOI: 10.1016/j.msard.2020.101988] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/26/2020] [Accepted: 02/06/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND Optic neuritis is a common manifestation of multiple sclerosis and frequently the presenting sign. The diagnosis of MS is heavily based on MRI findings but the latter is relatively insensitive in detecting optic nerve lesions. Identification of optic nerve lesion using ancillary tools such spectral-domain optical coherence tomography (SDOCT) by measuring the retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL), and visual-evoked potentials latencies (VEP) may facilitate early diagnosis and treatment of multiple sclerosis. OBJECTIVE To determine the optimal of SDOCT measures in RFNL and GCIPL and the VEP latency value for the identification of a prior symptomatic optic nerve lesion. METHODS Thirty patients with diagnosed clinically with optic neuritis and fifty healthy control subjects were tested with SDOCT and VEP and the sensitivity, specificity, negative and positive predictive values of optimal values from healthy controls and optic neuritis patients were determined of for the identification unilateral optic nerve lesion. RESULTS The inter-eye GCIPL difference of 3.5 µm is highly sensitive (100%) and specific (98%) in identifying unilateral optic nerve lesion, while lowest 5th percentile normal GCIPL threshold values of 71 µm was highly sensitive (100%) but less specific (83.3%). The inter-eye RNFL difference of 5.5 µm had a sensitivity of 70% and specificity of 90% in identifying optic nerve lesion while the lower 5th percentile normal RNFL value of 92.3 µm was poorly sensitive (40%). Finally, the 95th percentile normal VEP latency of 104.50 milliseconds had sensitivity of 80% and specificity of 76% in identifying optic nerve lesion. CONCLUSIONS The inter-eye GCIPL difference is a powerful index for identifying unilateral optic nerve lesion, while the inter-eye RNFL difference and 95th percentile normal VEP latency had very good sensitivity and specificity. These measures can be useful in the evaluation of the first demyelinating event of MS and therefor can facilitate early diagnosis and therapy.
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Affiliation(s)
- Raed Behbehani
- Al-Bahar Ophthalmology Center, Ibn Sina Hospital, P.O Box 1180, Kuwait.
| | - Abdullah Ali
- Al-Bahar Ophthalmology Center, Ibn Sina Hospital, P.O Box 1180, Kuwait
| | - Hamd Al-Omairah
- Al-Bahar Ophthalmology Center, Ibn Sina Hospital, P.O Box 1180, Kuwait
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Kwon YJ, Kim YH, Baek SH, Son MH, Lee JH, Kim BJ. Transorbital ultrasonography in acute optic neuritis: Can it be a supportive diagnostic tool? Mult Scler Relat Disord 2019; 31:54-58. [PMID: 30927732 DOI: 10.1016/j.msard.2019.03.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 12/12/2018] [Accepted: 03/22/2019] [Indexed: 11/17/2022]
Abstract
BACKGROUND Because of limitations of conventional tools for diagnosing optic neuritis (ON), transorbital ultrasonography (TOUS) was introduced as a promising tool to evaluate the optic nerve. However, studies demonstrating its utility are scarce. OBJECTIVE To assess the practical diagnostic value of TOUS in patients with ON along with other diagnostic tools such as visual evoked potential (VEP), MRI, and optical coherence tomography (OCT). METHODS Seventeen patients with first-attack unilateral acute ON were enrolled. Clinical characteristics, visual acuity, TOUS, MRI, VEP, and OCT results were evaluated. Bilateral optic nerves were scanned using TOUS to obtain axial images showing the optic nerve and the disc in the longitudinal plane. RESULTS TOUS revealed thickening of the optic nerve sheath and optic nerve diameter with sheath on the affected side compared with the unaffected side (p = 0.002 and p = 0.003, respectively). Time since onset of initial symptoms was inversely correlated with optic nerve diameter (ρ = -0.517, p = 0.040) and retinal nerve fiber layer thickness (ρ = -0.831, p < 0.001). CONCLUSION TOUS could be a cost-effective tool for morphologically evaluating acute ON showing a significant thickening of the optic nerve and sheath, although only a limited retrobulbar area could be explored.
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Affiliation(s)
- Ye-Ji Kwon
- Department of Neurology, Korea University Medical Center, Korea University College of Medicine, 73, Inchon-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Yoo Hwan Kim
- Department of Neurology, Korea University Medical Center, Korea University College of Medicine, 73, Inchon-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea; Department of Neurology, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - Seol-Hee Baek
- Department of Neurology, Korea University Medical Center, Korea University College of Medicine, 73, Inchon-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Myeong Hun Son
- Department of Neurology, Korea University Medical Center, Korea University College of Medicine, 73, Inchon-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Jung Hun Lee
- Department of Neurology, Korea University Medical Center, Korea University College of Medicine, 73, Inchon-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Byung-Jo Kim
- Department of Neurology, Korea University Medical Center, Korea University College of Medicine, 73, Inchon-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.
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Cadavid D, Balcer L, Galetta S, Aktas O, Ziemssen T, Vanopdenbosch LJ, Leocani L, Freedman MS, Plant GT, Preiningerova JL, Ziemssen F, Massacesi L, Chai Y, Xu L. Predictors of response to opicinumab in acute optic neuritis. Ann Clin Transl Neurol 2018; 5:1154-1162. [PMID: 30349850 PMCID: PMC6186935 DOI: 10.1002/acn3.620] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/06/2018] [Accepted: 06/18/2018] [Indexed: 01/03/2023] Open
Abstract
Objective The objective of this study was to evaluate prespecified and post hoc analyses in RENEW subgroups to identify participants more likely to benefit from opicinumab. Methods RENEW assessed the efficacy/safety of opicinumab versus placebo in participants with a first unilateral acute optic neuritis (AON) episode. Difference in visual evoked potential (VEP) latency of the affected eye at 24 weeks versus the fellow eye at baseline was the primary endpoint. Interactions between the primary endpoint and prespecified baseline variables (including age, timing of treatment initiation, and visual impairment) using the median as cut-off were evaluated in the per protocol population using analysis of covariance (ANCOVA); subgroups based on preexisting brain T2 lesion volume were also analyzed. Interactions between the primary endpoint and retinal ganglion cell layer/inner plexiform layer (RGCL/IPL) and retinal nerve fiber layer (RNFL) thickness were assessed post hoc as was weight gain by treatment. Results Treatment benefit of opicinumab (n = 33) over placebo (n = 36) on the primary endpoint was greatest in participants older than the median age at baseline (≥33 years); the difference versus placebo for baseline age ≥33 years was -14.17 msec [P = 0.01] versus -0.89 msec for baseline age <33 years, [P = 0.87]). Post hoc analysis showed that VEP latency recovery was significantly associated with less RGCL/IPL thinning (P = 0.0164), occurring early on. Interpretation Age was the strongest prespecified baseline characteristic associated with a treatment effect of opicinumab. A strong association between VEP latency recovery at week 24 and early RGCL/IPL preservation was observed.
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Affiliation(s)
| | - Laura Balcer
- Departments of Neurology, Population Health, and Ophthalmology New York University School of Medicine New York New York
| | - Steven Galetta
- Departments of Neurology, Population Health, and Ophthalmology New York University School of Medicine New York New York
| | - Orhan Aktas
- Department of Neurology Medical Faculty Heinrich-Heine-Universität Düsseldorf Düsseldorf Germany
| | - Tjalf Ziemssen
- MS Center Dresden Center of Clinical Neuroscience University Hospital Carl Gustav Carus Dresden University of Technology Dresden Germany
| | | | | | - Mark S Freedman
- University of Ottawa and the Ottawa Hospital Research Institute Ottawa Ontario Canada
| | - Gordon T Plant
- Moorfields Eye Hospital and The National Hospital for Neurology and Neurosurgery London United Kingdom
| | | | - Focke Ziemssen
- Center for Ophthalmology Eberhard Karls University of Tuebingen Tuebingen Germany
| | - Luca Massacesi
- Department of Neurosciences, Drugs and Child's Health University of Florence Florence Italy
| | - Yi Chai
- Biogen Cambridge Massachusetts
| | - Lei Xu
- Biogen Cambridge Massachusetts
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Dichoptic Metacontrast Masking Functions to Infer Transmission Delay in Optic Neuritis. PLoS One 2016; 11:e0163375. [PMID: 27711139 PMCID: PMC5053444 DOI: 10.1371/journal.pone.0163375] [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: 02/12/2016] [Accepted: 09/06/2016] [Indexed: 11/19/2022] Open
Abstract
Optic neuritis (ON) has detrimental effects on the transmission of neuronal signals generated at the earliest stages of visual information processing. The amount, as well as the speed of transmitted visual signals is impaired. Measurements of visual evoked potentials (VEP) are often implemented in clinical routine. However, the specificity of VEPs is limited because multiple cortical areas are involved in the generation of P1 potentials, including feedback signals from higher cortical areas. Here, we show that dichoptic metacontrast masking can be used to estimate the temporal delay caused by ON. A group of 15 patients with unilateral ON, nine of which had sufficient visual acuity and volunteered to participate, and a group of healthy control subjects (N = 8) were presented with flashes of gray disks to one eye and flashes of gray annuli to the corresponding retinal location of the other eye. By asking subjects to report the subjective visibility of the target (i.e. the disk) while varying the stimulus onset asynchrony (SOA) between disk and annulus, we obtained typical U-shaped masking functions. From these functions we inferred the critical SOAmax at which the mask (i.e. the annulus) optimally suppressed the visibility of the target. ON-associated transmission delay was estimated by comparing the SOAmax between conditions in which the disk had been presented to the affected and the mask to the other eye, and vice versa. SOAmax differed on average by 28 ms, suggesting a reduction in transmission speed in the affected eye. Compared to previously reported methods assessing perceptual consequences of altered neuronal transmission speed the presented method is more accurate as it is not limited by the observers’ ability to judge subtle variations in perceived synchrony.
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Pattern and motion-related visual-evoked potentials in neuroborreliosis: follow-up study. J Clin Neurophysiol 2012; 29:174-80. [PMID: 22469684 DOI: 10.1097/wnp.0b013e31824e1013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Visual-evoked potentials (VEPs) were used for objective testing of visual functions during treatment courses of Lyme neuroborreliosis (LNB) in adult patients in the Czech Republic. In 30 LNB patients with originally delayed VEP latencies, pattern-reversal (R-VEP) and motion onset (M-VEP) VEPs were repeatedly examined within 1 to 8 years. Six patients had Lyme optic neuritis (ON), five of them displayed prolonged latencies in both R-VEPs and M-VEPs, and one had only abnormal R-VEPs. The VEP recovery to normal latency values was in three of them. In the group of 24 LNB patients without ON, 14 patients displayed prolonged latencies only to motion stimuli, and 10 patients had abnormal latencies in both R-VEPs and M-VEPs. During the follow-up period, 7 patients displayed shortening to normal latencies. In 5 patients, VEPs latencies improved only partially, and in the remaining 12 patients, VEPs did not improve at all. This study provides objective evidence that in LNB, most of the patients without clinically manifesting ON display optic pathway involvement-predominantly magnocellular system/dorsal stream function changes. In patients with ON, however, mainly the parvocellular system is affected. About half of the patients without ON improved with a relatively long-time course of latency shortening.
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Whitford TJ, Ford JM, Mathalon DH, Kubicki M, Shenton ME. Schizophrenia, myelination, and delayed corollary discharges: a hypothesis. Schizophr Bull 2012; 38:486-94. [PMID: 20855415 PMCID: PMC3329979 DOI: 10.1093/schbul/sbq105] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Any etiological theory of schizophrenia must account for at least 3 distinctive features of the disorder, namely its excessive dopamine neurotransmission, its frequent periadolescent onset, and its bizarre, pathognomonic symptoms. In this article, we theorize that each of these features could arise from a single underlying cause--namely abnormal myelination of late-developing frontal white matter fasciculi. Specifically, we suggest that abnormalities in frontal myelination result in conduction delays in the efference copies initiated by willed actions. These conduction delays cause the resulting corollary discharges to be generated too late to suppress the sensory consequences of the willed actions. The resulting ambiguity as to the origins of these actions represents a phenomenologically and neurophysiologically significant prediction error. On a phenomenological level, the perception of salience in a self-generated action leads to confusion as to its origins and, consequently, passivity experiences and auditory hallucinations. On a neurophysiological level, this prediction error leads to the increased activity of dopaminergic neurons in the midbrain. This dopaminergic activity causes previously insignificant events to be perceived as salient, which exacerbates the budding hallucinations and passivity experiences and triggers additional first-rank symptoms such as delusions of reference. The article concludes with a discussion of the implications of the theory and some testable predictions which may form a worthwhile basis for future research.
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Affiliation(s)
- Thomas J. Whitford
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women’s Hospital, Harvard Medical School, 1249 Boylston Street, Boston, MA 02215,Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Melbourne, Victoria, Australia,To whom correspondence should be addressed; tel: +1-617-525-6119, fax: +1-617-525-6150, e-mail:
| | - Judith M. Ford
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA,Mental Health Service, San Francisco VA Medical Center, San Francisco, CA
| | - Daniel H. Mathalon
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA,Mental Health Service, San Francisco VA Medical Center, San Francisco, CA
| | - Marek Kubicki
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women’s Hospital, Harvard Medical School, 1249 Boylston Street, Boston, MA 02215,Clinical Neuroscience Division, Laboratory of Neuroscience, Department of Psychiatry, Boston Veterans Affairs Healthcare System, Harvard Medical School, Brockton, MA
| | - Martha E. Shenton
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women’s Hospital, Harvard Medical School, 1249 Boylston Street, Boston, MA 02215,Clinical Neuroscience Division, Laboratory of Neuroscience, Department of Psychiatry, Boston Veterans Affairs Healthcare System, Harvard Medical School, Brockton, MA
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Whitford TJ, Mathalon DH, Shenton ME, Roach BJ, Bammer R, Adcock RA, Bouix S, Kubicki M, De Siebenthal J, Rausch AC, Schneiderman JS, Ford JM. Electrophysiological and diffusion tensor imaging evidence of delayed corollary discharges in patients with schizophrenia. Psychol Med 2011; 41:959-969. [PMID: 20663254 PMCID: PMC3807011 DOI: 10.1017/s0033291710001376] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Patients with schizophrenia (SZ) characteristically exhibit supranormal levels of cortical activity to self-induced sensory stimuli, ostensibly because of abnormalities in the neural signals (corollary discharges, CDs) normatively involved in suppressing the sensory consequences of self-generated actions. The nature of these abnormalities is unknown. This study investigated whether SZ patients experience CDs that are abnormally delayed in their arrival at the sensory cortex. METHOD Twenty-one patients with SZ and 25 matched control participants underwent electroencephalography (EEG). Participants' level of cortical suppression was calculated as the amplitude of the N1 component evoked by a button press-elicited auditory stimulus, subtracted from the N1 amplitude evoked by the same stimulus presented passively. In the three experimental conditions, the auditory stimulus was delivered 0, 50 or 100 ms subsequent to the button-press. Fifteen SZ patients and 17 healthy controls (HCs) also underwent diffusion tensor imaging (DTI), and the fractional anisotropy (FA) of participants' arcuate fasciculus was used to predict their level of cortical suppression in the three conditions. RESULTS While the SZ patients exhibited subnormal N1 suppression to undelayed, self-generated auditory stimuli, these deficits were eliminated by imposing a 50-ms, but not a 100-ms, delay between the button-press and the evoked stimulus. Furthermore, the extent to which the 50-ms delay normalized a patient's level of N1 suppression was linearly related to the FA of their arcuate fasciculus. CONCLUSIONS These data suggest that SZ patients experience temporally delayed CDs to self-generated auditory stimuli, putatively because of structural damage to the white-matter (WM) fasciculus connecting the sites of discharge initiation and destination.
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Affiliation(s)
- T J Whitford
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, 1249 Boylston Street, Boston, MA 02215, USA.
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Nakamura H, Miyamoto K, Yokota S, Ogino K, Yoshimura N. Focal macular photopic negative response in patients with optic neuritis. Eye (Lond) 2011; 25:358-64. [PMID: 21212800 DOI: 10.1038/eye.2010.205] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To investigate, by focal macular electroretinography (ERG), the change of photopic negative response (PhNR) in the recovery of visual function in patients with optic neuritis. METHODS Focal macular ERG was recorded from nine patients with acute optic neuritis (38.6 ± 10.2 years). The photostimulator device projected 15° visual angle spotlight onto the macula. Focal macular ERG recording was performed at the onset and at 1 month and 6 months after the onset of optic neuritis. The results were compared between each recording for seven of the patients. RESULTS All patients decreased in the vision below 20/100 and had central scotoma. Vision improved more than 20/20 within 1 month and full-visual field recovered within 6 months after the onset in all patients. The amplitude of the a-wave, b-wave, and PhNR of focal macular ERG at the onset was significantly attenuated in eyes with optic neuritis (66.8 ± 15.5, 65.8 ± 17.7, and 65.2 ± 14.4% of normal control, respectively). The amplitude of the a-wave and b-wave increased gradually after steroid pulse therapy. The increase in a-wave amplitude was significant at 6 months (P = 0.046), whereas the PhNR amplitude did not show any significant change over 6 months after the onset of optic neuritis. CONCLUSIONS Our results suggest that inflammation at the onset of optic neuritis leads to functional deficits that extend to at least the inner nuclear layers of the retina, and that all but the ganglion cell layers of retina recover.
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Affiliation(s)
- H Nakamura
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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Whitford TJ, Kubicki M, Ghorashi S, Schneiderman JS, Hawley KJ, McCarley RW, Shenton ME, Spencer KM. Predicting inter-hemispheric transfer time from the diffusion properties of the corpus callosum in healthy individuals and schizophrenia patients: a combined ERP and DTI study. Neuroimage 2010; 54:2318-29. [PMID: 20977941 DOI: 10.1016/j.neuroimage.2010.10.048] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 10/11/2010] [Accepted: 10/13/2010] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND Several theories of schizophrenia have emphasized the role of aberrant neural timing in the etiology of the disease, possibly as a consequence of conduction delays caused by structural damage to the white-matter fasciculi. Consistent with this theory, increased inter-hemispheric transmission times (IHTTs) to unilaterally-presented visual stimuli have been reported in patients with schizophrenia. The present study investigated whether or not these IHTT abnormalities could be underpinned by structural damage to the visual fibers of the corpus callosum. METHODS Thirty three schizophrenia patients and 22 matched controls underwent Event Related Potential (ERP) recording, and a subset of 19 patients and 16 controls also underwent 3T Diffusion-Tensor Imaging (DTI). Unilateral visual stimuli (squares, 2×2 degrees) were presented 6 degrees lateral to either side of a central fixation point. IHTTs (ipsilateral minus contralateral latencies) were calculated for the P1 and N1 components at parietal-occipital sites in current source density-transformed ERPs. The visual fibers of the corpus callosum were extracted with streamline tractography and the diffusion metrics of Fractional Anisotropy (FA) and Mode calculated. RESULTS While both subject groups exhibited highly significant IHTTs across a range of posterior electrode pairs, and significantly shorter IHTTs from left-to-right hemisphere than vice versa, no significant groupwise differences in IHTT were observed. However, participants' IHTTs were linearly related to their FA and Mode, with longer IHTTs being associated with lower FA and more prolate diffusion ellipsoids. CONCLUSIONS These results suggest that IHTTs are estimable from DTI measures of white matter integrity. In light of the range of diffusion abnormalities that have been reported in patients with schizophrenia, particularly in frontal fasciculi, these results support the conjecture that schizophrenia is associated with abnormalities in neural timing.
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Affiliation(s)
- Thomas J Whitford
- Psychiatry Neuroimaging Laboratory, Brigham and Women's Hospital, HarvardMedical School, Boston, MA 02215, USA.
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Jenkins TM, Toosy AT, Ciccarelli O, Miszkiel KA, Wheeler-Kingshott CA, Henderson AP, Kallis C, Mancini L, Plant GT, Miller DH, Thompson AJ. Neuroplasticity predicts outcome of optic neuritis independent of tissue damage. Ann Neurol 2010; 67:99-113. [DOI: 10.1002/ana.21823] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Niklas A, Sebraoui H, Heß E, Wagner A, Then Bergh F. Outcome measures for trials of remyelinating agents in multiple sclerosis: retrospective longitudinal analysis of visual evoked potential latency. Mult Scler 2009; 15:68-74. [DOI: 10.1177/1352458508095731] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective Visual evoked potentials (VEP) may be suitable surrogate outcome measures in multiple sclerosis (MS) remyelination trials. The extent of spontaneous changes of subclinically delayed VEP is unknown, whereas VEP improve after acute optic neuritis (ON). Methods In all, 124 patients with three VEP recordings at least 3 months apart: 71 patients with MS who had never suffered clinical ON; 53 patients with ON (isolated ON or ON as an attack of MS at first recording). Latencies of P100 were analyzed by multivariate analysis of variance. Results Eyes of patients with MS had a mean P100 latency of 110.2 ms, worsening mildly over time ( n = 104 eyes, P = 0.022). MS patients' eyes with subclinical demyelination (delayed P100 latency at first recording >116 ms) showed no significant evidence of remyelination ( n = 24 eyes, P = 0.27). By contrast, in ON patients' affected eyes, mean P100 latency decreased ( P = 0.001), whereas unaffected eyes remained stable ( P = 0.26). Clinically non-affected eyes from both diagnostic groups with subclinically prolonged latencies remained stable ( n = 32: mean P100 at 124.8 ± 10.7, 123.5 ± 13.6, and 122.8 ± 13.1 ms; P = 0.57), whereas non-affected eyes with normal latency at baseline deteriorated slightly ( P = 0.001). A subgroup with more homogeneously defined follow-up periods confirmed this observation. Non-affected eyes selected for stability (difference <5 ms) between first and second recording deteriorated (normal baseline, n = 66 eyes, P = 0.013) or remained stable (prolonged baseline, n = 18 eyes, 95% confidence interval of change –5.42 to +6.89 ms, P = 0.805). Conclusion Prolonged P100 latencies in eyes never affected by clinical ON remain stable and thus can be used as surrogate outcome measure for remyelination trials.
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Affiliation(s)
- A Niklas
- Klinik und Poliklinik für Neurologie, Universität Leipzig, Leipzig, Germany; Translational Centre for Regenerative Medicine (TRM-Leipzig), Universität Leipzig, Leipzig, Germany
| | - H Sebraoui
- Klinik und Poliklinik für Neurologie, Universität Leipzig, Leipzig, Germany
| | - E Heß
- Klinik und Poliklinik für Neurologie, Universität Leipzig, Leipzig, Germany; Translational Centre for Regenerative Medicine (TRM-Leipzig), Universität Leipzig, Leipzig, Germany
| | - A Wagner
- Klinik und Poliklinik für Neurologie, Universität Leipzig, Leipzig, Germany
| | - F Then Bergh
- Klinik und Poliklinik für Neurologie, Universität Leipzig, Leipzig, Germany; Translational Centre for Regenerative Medicine (TRM-Leipzig), Universität Leipzig, Leipzig, Germany
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Pueyo V, Martin J, Fernandez J, Almarcegui C, Ara J, Egea C, Pablo L, Honrubia F. Axonal loss in the retinal nerve fiber layer in patients with multiple sclerosis. Mult Scler 2008; 14:609-14. [DOI: 10.1177/1352458507087326] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective To quantify axonal loss in the retinal nerve fiber layer (RNFL) in patients with multiple sclerosis (MS), with and without a history of optic neuritis, by means of ocular imaging technologies. Methods This cross-sectional study enrolled 50 patients with MS and 25 age- and sex-matched healthy controls. All patients underwent neurologic assessment and a complete ophthalmic examination that included visual acuity, visual field examination, optical coherence tomography (OCT), scanning laser polarimetry (GDx) and visual evoked potentials (VEPs). Visual parameters and RNFL measurements were evaluated in MS eyes with a prior optic neuritis episode (MS-ON), with no prior episode (MS-NON) and control subjects. Results There were significant differences ( p < 0.05, analysis of variance) between MS-ON ( n = 25 eyes) and healthy eyes ( n = 25 eyes) for all RNFL parameters measured by OCT and GDx. Significant differences between MS-NON ( n = 75 eyes) and healthy eyes were also found for most of these parameters. RNFL thickness in the temporal quadrant was the parameter with the greatest differences between groups (71.79 μm in healthy eyes, 60.29 μm in MS-NON and 53.92 μm in MS-ON, p < 0.0005). Although there was a highly significant but moderate correlation between RNFL thickness and duration of the disease, no correlation was observed between RNFL thickness and neurologic impairment (Expanded Disability Status Scale). Conclusions Axonal loss was detected not only in MS eyes with a previous acute optic neuritis, but also in MS eyes with no known optic neuritis episode. Structural abnormalities correlate with functional assessments of the optic nerve.
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Affiliation(s)
- V Pueyo
- Isabel la Catolica, Zaragoza, Spain,
| | - J Martin
- Isabel la Catolica, Zaragoza, Spain
| | | | | | - J Ara
- Isabel la Catolica, Zaragoza, Spain
| | - C Egea
- Isabel la Catolica, Zaragoza, Spain
| | - L Pablo
- Isabel la Catolica, Zaragoza, Spain
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Schumacher M, Guennoun R, Ghoumari A, Massaad C, Robert F, El-Etr M, Akwa Y, Rajkowski K, Baulieu EE. Novel perspectives for progesterone in hormone replacement therapy, with special reference to the nervous system. Endocr Rev 2007; 28:387-439. [PMID: 17431228 DOI: 10.1210/er.2006-0050] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The utility and safety of postmenopausal hormone replacement therapy has recently been put into question by large clinical trials. Their outcome has been extensively commented upon, but discussions have mainly been limited to the effects of estrogens. In fact, progestagens are generally only considered with respect to their usefulness in preventing estrogen stimulation of uterine hyperplasia and malignancy. In addition, various risks have been attributed to progestagens and their omission from hormone replacement therapy has been considered, but this may underestimate their potential benefits and therapeutic promises. A major reason for the controversial reputation of progestagens is that they are generally considered as a single class. Moreover, the term progesterone is often used as a generic one for the different types of both natural and synthetic progestagens. This is not appropriate because natural progesterone has properties very distinct from the synthetic progestins. Within the nervous system, the neuroprotective and promyelinating effects of progesterone are promising, not only for preventing but also for reversing age-dependent changes and dysfunctions. There is indeed strong evidence that the aging nervous system remains at least to some extent sensitive to these beneficial effects of progesterone. The actions of progesterone in peripheral target tissues including breast, blood vessels, and bones are less well understood, but there is evidence for the beneficial effects of progesterone. The variety of signaling mechanisms of progesterone offers exciting possibilities for the development of more selective, efficient, and safe progestagens. The recognition that progesterone is synthesized by neurons and glial cells requires a reevaluation of hormonal aging.
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Affiliation(s)
- Michael Schumacher
- INSERM UMR 788, 80, rue du Général Leclerc, 94276 Kremlin-Bicêtre, France.
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15
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Abstract
Remyelination is the phenomenon by which new myelin sheaths are generated around axons in the adult central nervous system (CNS). This follows the pathological loss of myelin in diseases like multiple sclerosis (MS). Remyelination can restore conduction properties to axons (thereby restoring neurological function) and is increasingly believed to exert a neuroprotective role on axons. Remyelination occurs in many MS lesions but becomes increasingly incomplete/inadequate and eventually fails in the majority of lesions and patients. Efforts to understand the causes for this failure of regeneration have fueled research into the biology of remyelination and the complex, interdependent cellular and molecular factors that regulate this process. Examination of the mechanisms of repair of experimental lesions has demonstrated that remyelination occurs in two major phases. The first consists of colonization of lesions by oligodendrocyte progenitor cells (OPCs), the second the differentiation of OPCs into myelinating oligodendrocytes that contact demyelinated axons to generate functional myelin sheaths. Several intracellular and extracellular molecules have been identified that mediate these two phases of repair. Theoretically, the repair of demyelinating lesions can be promoted by enhancing the intrinsic repair process (by providing one or more remyelination-enhancing factors or via immunoglobulin therapy). Alternatively, endogenous repair can be bypassed by introducing myelinogenic cells into demyelinated areas; several cellular candidates have been identified that can mediate repair of experimental demyelinating lesions. Future challenges confronting therapeutic strategies to enhance remyelination will involve the translation of findings from basic science to clinical demyelinating disease.
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Affiliation(s)
- Divya M Chari
- Cambridge Centre for Brain Repair and Veterinary Medicine, University of Cambridge, Cambridge CB3OES, United Kingdom
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16
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Trip SA, Schlottmann PG, Jones SJ, Li WY, Garway-Heath DF, Thompson AJ, Plant GT, Miller DH. Optic nerve atrophy and retinal nerve fibre layer thinning following optic neuritis: Evidence that axonal loss is a substrate of MRI-detected atrophy. Neuroimage 2006; 31:286-93. [PMID: 16446103 DOI: 10.1016/j.neuroimage.2005.11.051] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Revised: 11/21/2005] [Accepted: 11/28/2005] [Indexed: 11/30/2022] Open
Abstract
Magnetic resonance imaging (MRI) measures of brain atrophy are often considered to be a marker of axonal loss in multiple sclerosis (MS) but evidence is limited. Optic neuritis is a common manifestation of MS and results in optic nerve atrophy. Retinal nerve fibre layer (RNFL) imaging is a non-invasive way of detecting axonal loss following optic neuritis. We hypothesise that if the optic nerve atrophy that develops following optic neuritis is contributed to by axonal loss, it will correlate with thinning of the RNFL. Twenty-five patients were studied at least 1 year after a single unilateral attack of optic neuritis without recurrence, with a selection bias towards incomplete recovery. They had MR quantification of optic nerve cross-sectional area and optic nerve lesion length, as well as optical coherence tomography (OCT) measurement of mean RNFL thickness and macular volume, quantitative visual testing, and visual evoked potentials (VEPs). Fifteen controls were also studied. Significant optic nerve atrophy (mean decrease 30% versus controls), RNFL thinning (mean decrease 33% versus controls), and macular volume loss occurred in patients' affected eyes when compared with patients' unaffected eyes and healthy controls. The optic nerve atrophy was correlated with the RNFL thinning, macular volume loss, visual acuity, visual field mean deviation, and whole field VEP amplitude but not latency. These findings suggest that axonal loss contributes to optic nerve atrophy following a single attack of optic neuritis. By inference, axonal loss due to other post-inflammatory brain lesions is likely to contribute to the global MRI measure of brain atrophy in multiple sclerosis.
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Affiliation(s)
- S Anand Trip
- NMR Research Unit, Department of Neuroinflammation, Institute of Neurology, University College London, UK.
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17
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Lachapelle F, Bachelin C, Moissonnier P, Nait‐Oumesmar B, Hidalgo A, Fontaine D, Evercooren AB. Failure of remyelination in the nonhuman primate optic nerve. Brain Pathol 2005; 15:198-207. [PMID: 16196386 PMCID: PMC8096034 DOI: 10.1111/j.1750-3639.2005.tb00521.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The mechanisms limiting myelin repair in human central nervous system (CNS) remain unknown. Models of induced-demyelination in the nonhuman primate CNS may provide the necessary grounds to unravel these mechanisms and to investigate the development of strategies to promote myelin repair. To address this issue, we developed a model of focal demyelination in the adult Macaca fascicularis CNS. Lesions were induced by microinjection of lysolecithin in the optic nerve and the profile of remyelination was compared to that of lysolecithin-induced lesions of the spinal cord. In both structures, the time-course of demyelination as well as the onset of remyelination were found to be similar to that in the rodent CNS. While spinal cord lesions were remyelinated within 6 weeks, optic nerve lesions remained demyelinated for up to 3 months post-injection. The failure of remyelination in the optic nerve correlated with a reduced density of NG2+ oligodendrocyte progenitor cells, the presence of oligodendrocytes that fail to ensheath naked axons in the lesion and the absence of astrocyte recruitment in the lesion compared with spinal cord lesions. Our present data suggest that the reduced oligodendrocyte progenitor population, the improper activation of oligodendrocytes at the onset of remyelination in the optic nerve, and possibly, the involvement of astrocytes contribute to the chronicity of the optic nerve lesion. This model of chronic demyelination in the macaque optic nerve stresses its pertinence to unraveling the mechanisms limiting remyelination in multiple sclerosis.
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Affiliation(s)
- François Lachapelle
- Institut National de la Santé et de la Recherche Médicale, Université Pierre et Marie Curie UMR 546, CHU de la Salpêtrière, Paris, France
- Authors contributed equally to the present study
| | - Corinne Bachelin
- Institut National de la Santé et de la Recherche Médicale, Université Pierre et Marie Curie UMR 546, CHU de la Salpêtrière, Paris, France
- Authors contributed equally to the present study
| | | | - Brahim Nait‐Oumesmar
- Institut National de la Santé et de la Recherche Médicale, Université Pierre et Marie Curie UMR 546, CHU de la Salpêtrière, Paris, France
| | | | | | - Anne Baron‐Van Evercooren
- Institut National de la Santé et de la Recherche Médicale, Université Pierre et Marie Curie UMR 546, CHU de la Salpêtrière, Paris, France
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18
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Trip SA, Wheeler-Kingshott C, Jones SJ, Li WY, Barker GJ, Thompson AJ, Plant GT, Miller DH. Optic nerve diffusion tensor imaging in optic neuritis. Neuroimage 2005; 30:498-505. [PMID: 16242968 DOI: 10.1016/j.neuroimage.2005.09.024] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Revised: 09/13/2005] [Accepted: 09/19/2005] [Indexed: 11/28/2022] Open
Abstract
Diffusion tensor magnetic resonance imaging (DT-MRI) provides in vivo information about the pathology of multiple sclerosis lesions. Increases in mean diffusivity (MD) and reductions in fractional anisotropy (FA) have been found and may represent axonal disruption. The optic nerve is an ideal structure for study by DT-MRI but previous clinical studies did not obtain the full diffusion tensor necessary to calculate MD and FA. In this study, a technique that was specifically developed to achieve full diffusion tensor measurements from the optic nerve (zonal oblique multislice (ZOOM) echoplanar imaging) was applied to 25 patients with a single unilateral episode of optic neuritis at least one year previously, and 15 controls. The intraorbital nerves were segmented on non-diffusion-weighted images and the regions of interest transferred to MD, FA, and eigenvalue maps to obtain quantitative data. Quantitative visual testing and electrophysiology were also performed. In affected nerves, mean MD and mean orthogonal eigenvalue lambda( perpendicular) were elevated, and mean FA reduced compared with clinically unaffected contralateral nerves (P < 0.001) and control nerves (P < 0.001). The mean principal eigenvalue lambda\\ was significantly increased in affected nerves compared to contralateral unaffected nerves (P = 0.04) but not compared to control nerves (P = 0.13). There was no association of clinical measures of visual function in affected eyes with the DT-MRI parameters but there was a significant correlation of the whole field visual evoked potential (VEP) amplitude with MD (r = -0.57, P = 0.006) and lambda( perpendicular) (r = -0.56, P = 0.007). These findings suggest that optic nerve DT-MRI measures provide an indication of the structural integrity of axons.
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Affiliation(s)
- S Anand Trip
- NMR Research Unit, Department of Neuroinflammation, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
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19
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Schumacher M, Guennoun R, Robert F, Carelli C, Gago N, Ghoumari A, Gonzalez Deniselle MC, Gonzalez SL, Ibanez C, Labombarda F, Coirini H, Baulieu EE, De Nicola AF. Local synthesis and dual actions of progesterone in the nervous system: neuroprotection and myelination. Growth Horm IGF Res 2004; 14 Suppl A:S18-S33. [PMID: 15135772 DOI: 10.1016/j.ghir.2004.03.007] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Progesterone (PROG) is synthesized in the brain, spinal cord and peripheral nerves. Its direct precursor pregnenolone is either derived from the circulation or from local de novo synthesis as cytochrome P450scc, which converts cholesterol to pregnenolone, is expressed in the nervous system. Pregnenolone is converted to PROG by 3beta-hydroxysteroid dehydrogenase (3beta-HSD). In situ hybridization studies have shown that this enzyme is expressed throughout the rat brain, spinal cord and dorsal root ganglia (DRG) mainly by neurons. Macroglial cells, including astrocytes, oligodendroglial cells and Schwann cells, also have the capacity to synthesize PROG, but expression and activity of 3beta-HSD in these cells are regulated by cellular interactions. Thus, Schwann cells convert pregnenolone to PROG in response to a neuronal signal. There is now strong evidence that P450scc and 3beta-HSD are expressed in the human nervous system, where PROG synthesis also takes place. Although there are only a few studies addressing the biological significance of PROG synthesis in the brain, the autocrine/paracrine actions of locally synthesized PROG are likely to play an important role in the viability of neurons and in the formation of myelin sheaths. The neuroprotective effects of PROG have recently been documented in a murine model of spinal cord motoneuron degeneration, the Wobbler mouse. The treatment of symptomatic Wobbler mice with PROG for 15 days attenuated the neuropathological changes in spinal motoneurons and had beneficial effects on muscle strength and the survival rate of the animals. PROG may exert its neuroprotective effects by regulating expression of specific genes in neurons and glial cells, which may become hormone-sensitive after injury. The promyelinating effects of PROG were first documented in the mouse sciatic nerve and in co-cultures of sensory neurons and Schwann cells. PROG also promotes myelination in the brain, as shown in vitro in explant cultures of cerebellar slices and in vivo in the cerebellar peduncle of aged rats after toxin-induced demyelination. Local synthesis of PROG in the brain and the neuroprotective and promyelinating effects of this neurosteroid offer interesting therapeutic possibilities for the prevention and treatment of neurodegenerative diseases, for accelerating regenerative processes and for preserving cognitive functions during aging.
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20
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Jones SJ, Brusa A. Neurophysiological evidence for long-term repair of MS lesions: implications for axon protection. J Neurol Sci 2003; 206:193-8. [PMID: 12559510 DOI: 10.1016/s0022-510x(02)00428-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
After recovery from the acute stage of optic neuritis, a marked prolongation in the latencies of visual evoked potentials (VEPs) is typically observed. We have conducted three studies (one cross-sectional, two prospective), aimed at elucidating the progressive shortening of VEP latency, which frequently ensues over the following months or years. This has been shown to be a progressive process and a prevalent tendency in the patient population, proceeding for more than 2 years in spite of the fact that very little functional improvement in vision occurs after the first few months. We argue that the underlying process of repair is most likely to involve remyelination of demyelinated optic nerve axons. Rather than restoration of visual function (which may be virtually complete after as short a period as 3 months), the main importance of the long-term myelin repair process may consist in protecting demyelinated axons from subsequent, permanent degeneration. In the VEPs of the acutely unaffected fellow eyes followed up over 3 years, we observed an asymptomatic deterioration, possibly due to insidious processes of demyelination and/or axonal degeneration. Even in the relapsing/remitting stage of MS, therefore, there is electrophysiological evidence for involvement of clinically asymptomatic axons, which, in the later stages, may be manifested as progressive functional deterioration.
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Affiliation(s)
- Steve J Jones
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK.
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21
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Diem R, Tschirne A, Bähr M. Decreased amplitudes in multiple sclerosis patients with normal visual acuity: a VEP study. J Clin Neurosci 2003; 10:67-70. [PMID: 12464525 DOI: 10.1016/s0967-5868(02)00172-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Primary demyelination with relative preservation of axons is considered to be one pathological hallmark of multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system. However, imaging and pathomorphological studies have stimulated a recent re-emergence of interest in the axonal, neurodegenerative aspect of MS pathology. Axonal injury appears to be a key factor of disability and permanent neurological deficit in MS patients. In the present electrophysiological study, visual potentials evoked by pattern reversal (VEPs) were recorded in 25 MS patients with normal visual acuity and unimpaired visual functions. Compared to a control population, VEP amplitudes for two different spatial frequencies were significantly decreased. From this observation, we conclude that an underlying pathological process threatening axonal integrity may not be reliably reflected by clinical parameters due to the distinct ability of the visual system to compensate for axonal loss. Pattern VEP may thus serve as an objective tool to diagnose and to monitor axonal pathology in MS. Focal conduction block due to demyelination as a cause for reduced VEP amplitudes can not be fully excluded, but would appear less likely since latency prolongation in the MS group was moderate compared to controls.
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Affiliation(s)
- R Diem
- Neurologische Universitätsklinik, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.
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22
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Toosy AT, Werring DJ, Bullmore ET, Plant GT, Barker GJ, Miller DH, Thompson AJ. Functional magnetic resonance imaging of the cortical response to photic stimulation in humans following optic neuritis recovery. Neurosci Lett 2002; 330:255-9. [PMID: 12270641 DOI: 10.1016/s0304-3940(02)00700-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Recovery from optic neuritis has been shown to be associated with an abnormal functional MRI (fMRI) response following exposure of the eye to an epoch based (ON-OFF design) flickering photic stimulus. Visual cortex activation is reduced during photic stimulation, whilst extra-occipital areas are extensively activated with a peak blood oxygen level dependent response during the OFF phase of the stimulus paradigm. We performed a further fMRI experiment to determine whether the abnormal extra-occipital response is a phase-specific phenomenon or whether it results from a delayed haemodynamic response. A cohort of patients that recovered from optic neuritis was studied, this time using a longer photic stimulation epoch (40 s). The extra-occipital response again peaked during the baseline condition, indicating that the phenomenon is phase dependent. Our results also reinforce the important findings of extra-occipital activation following optic neuritis which may represent an adaptive reorganization of the cerebral response.
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Affiliation(s)
- A T Toosy
- NMR Research Unit, Institute of Neurology, Queen Square, London WC1N 3BG, UK
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23
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Brusa A, Jones SJ, Plant GT. Long-term remyelination after optic neuritis: A 2-year visual evoked potential and psychophysical serial study. Brain 2001; 124:468-79. [PMID: 11222447 DOI: 10.1093/brain/124.3.468] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Thirty-one patients were followed-up, at 3-month intervals for the first year and at 6-month intervals for the second year, after an episode of optic neuritis. The object was to confirm previous evidence for a progressive shortening of visual evoked potential (VEP) latencies and to determine whether this is associated with any change in the clinical ocular examination, visual fields or contrast sensitivity. VEP latencies were found to decrease significantly during both the first and (less strikingly) the second year, the most marked changes occurring between 3 and 6 months. Contrast sensitivity improved during the first 9 months, but subsequently tended (non-significantly) to deteriorate. A similarly transient improvement in central visual field sensitivity was seen in a subgroup of patients with clinically overt multiple sclerosis. In the data from the acutely unaffected fellow eyes, no significant changes in VEP parameters or functional indices were observed. The findings extend those of a previous study which showed significant shortening of VEP latencies between 6 months and 3 years without significant functional improvement. Over this period, a significant prolongation of VEP latencies occurred in the asymptomatic fellow eye, accompanied by contrast sensitivity deterioration. Taken in conjunction, the two studies suggest that recovery processes involving remyelination or, possibly, ion channel reorganization proceed for at least 2 years. The concurrent effects of insidious demyelination and/or axonal degeneration (also occurring in the fellow optic nerve) are initially masked by the recovery process, but gradually become more evident. The functional benefits of the long-term recovery process are relatively minor and are usually reversed within a few years. Nevertheless, it is suggested that long-term remyelination may perform an important role in protecting demyelinated axons from degeneration. Understanding the factors which promote long-term remyelination may have significant implications for therapy in multiple sclerosis.
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Affiliation(s)
- A Brusa
- Department of Clinical Neurophysiology, The National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
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24
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Rinalduzzi S, Brusa A, Jones SJ. Variation of visual evoked potential delay to stimulation of central, nasal, and temporal regions of the macula in optic neuritis. J Neurol Neurosurg Psychiatry 2001; 70:28-35. [PMID: 11118244 PMCID: PMC1763456 DOI: 10.1136/jnnp.70.1.28] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To compare the degree of visual evoked potential (VEP) delay to stimulation of central, nasal, and temporal regions of the macula in optic neuritis, to determine whether the differential involvement of parvocellular and magnocellular fibre types suggested by other studies is governed by retinotopic factors. METHODS VEPs were recorded to reversal of 40' checks in the central (4 degrees radius) and the left and right surrounding regions of the visual field (as far as 10 degrees vertical and 14 degrees horizontal) in 30 patients recently recovered from the acute stage of optic neuritis, and in 17 age matched controls. RESULTS In the control group, VEP latencies were similar to stimulation of the central and temporal regions of the macula, marginally shorter from the nasal region. In the patients with optic neuritis, VEPs were significantly more delayed from the central region, on average by about twice as much as from the nasal and temporal regions. Delays seen in some of the VEPs from the patients' fellow eyes tended to be more uniformly distributed. CONCLUSIONS Although the central region of the macula is where the density of parvocellular innervation is greatest, there is no reason to suppose that the VEPs to stimulation of the nasal and temporal regions (almost all P100 activity arising from within the central 10 degrees ) are mediated by fibres of another type. Consequently it is suggested that the central fibres were most affected by demyelination, not on account of their belonging to the parvocellular type but because of their particular situation in the optic nerve. Centrally located fibres may experience greater exposure to factors causing demyelination, or fibres located closer to the edge of the plaque may undergo more effective remyelination in the first few weeks after the acute episode.
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Affiliation(s)
- S Rinalduzzi
- Department of Clinical Neurophysiology, The National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
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25
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Werring DJ, Bullmore ET, Toosy AT, Miller DH, Barker GJ, MacManus DG, Brammer MJ, Giampietro VP, Brusa A, Brex PA, Moseley IF, Plant GT, McDonald WI, Thompson AJ. Recovery from optic neuritis is associated with a change in the distribution of cerebral response to visual stimulation: a functional magnetic resonance imaging study. J Neurol Neurosurg Psychiatry 2000; 68:441-9. [PMID: 10727479 PMCID: PMC1736877 DOI: 10.1136/jnnp.68.4.441] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES Recovery to normal or near normal visual acuity is usual after acute demyelinating optic neuritis, despite the frequent persistence of conduction abnormalities as evidenced by the visual evoked potential (VEP). This raises the possibility that cortical adaptation to a persistently abnormal input contributes to the recovery process. The objective of this study was to investigate the pattern of cerebral response to a simple visual stimulus in recovered patients in comparison to normal subjects. METHODS Functional magnetic resonance imaging (fMRI) was used to study the brain activation pattern induced by a periodic monocular 8Hz photic stimulus in seven patients who had recovered from a single episode of acute unilateral optic neuritis, and in seven normal controls. VEPs and structural optic nerve MRI were performed on patients. RESULTS Stimulation of either eye in controls activated only the occipital visual cortex. However, in patients, stimulation of the recovered eye also induced extensive activation in other areas including the insula-claustrum, lateral temporal and posterior parietal cortices, and thalamus; stimulation of the clinically unaffected eye activated visual cortex and right insula-claustrum only. The volume of extraoccipital activation in patients was strongly correlated with VEP latency (r = 0.71, p = 0.005). CONCLUSIONS The extraoccipital areas that were activated in patients all have extensive visual connections, and some have been proposed as sites of multimodal sensory integration. The results indicate a functional reorganisation of the cerebral response to simple visual stimuli after optic neuritis that may represent an adaptive response to a persistently abnormal input. Whether this is a necessary part of the recovery process remains to be determined.
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Affiliation(s)
- D J Werring
- NMR Research Unit, Institute of Neurology, Queen Square, London WC1N 3BG, UK
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26
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Shields SA, Gilson JM, Blakemore WF, Franklin RJ. Remyelination occurs as extensively but more slowly in old rats compared to young rats following gliotoxin-induced CNS demyelination. Glia 1999; 28:77-83. [PMID: 10498825 DOI: 10.1002/(sici)1098-1136(199910)28:1<77::aid-glia9>3.0.co;2-f] [Citation(s) in RCA: 188] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Age is one of the many factors that influence remyelination following CNS demyelination, although it is not clear whether it is the extent or rate of remyelination that is affected. To resolve this issue we have compared remyelination in young and old adult rat CNS following gliotoxin-induced demyelination. Remyelination of areas of ethidium bromide-induced demyelination in the caudal cerebellar peduncle reached completion by 4 weeks in young adult rats (2 months) but was not complete until 9 weeks in old adult rats (9-12 months). We have also shown that remyelination of lysolecithin-induced demyelination in the spinal white matter of old adult rats (18 months) can be extensive, with longer survival times (8 weeks) than have previously been examined. Thus, it is the rate rather than the extent of remyelination that changes in the ageing CNS. These results have important implications for understanding the mechanisms of remyelination, indicating that remyelination need not occur rapidly for it to be extensive. The capacity for the process of remyelination to continue over many weeks must also be borne in mind when assessing remyelination-enhancement strategies either by transplantation or promotion of endogenous mechanisms.
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Affiliation(s)
- S A Shields
- Department of Clinical Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
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27
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Frederiksen JL, Petrera J. Serial visual evoked potentials in 90 untreated patients with acute optic neuritis. Surv Ophthalmol 1999; 44 Suppl 1:S54-62. [PMID: 10548117 DOI: 10.1016/s0039-6257(99)00095-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To establish the value of visual evoked potentials (VEPs) for monitoring disease evolution, we undertook a population-based study of 90 untreated patients 12 to 57 years of age (median, 32 years) at the onset of optic neuritis (ON) and after 2, 4, 12, and 52 weeks. Optic neuritis was monosymptomatic (AMON) in 58 patients and part of the clinically definite multiple sclerosis (CDMS) in 32 patients. The VEP was abnormal in eyes with acute ON in 69 (77%) of 90 patients at onset and in 80 (89%) of 90 patients at one or more of the follow-up sessions. In eyes with acute ON, normalization of an initially abnormal VEP was observed during 1-year follow-up in 13 (19%) of 69 patients. At onset of ON, VEP was abnormal in 35% of the clinically unaffected eyes. By parametric analysis of variance, the latencies (P = 0.0058), the amplitudes (P = 0.0298), and the combined VEP scores (P = 0.0345) in the eyes with acute ON were significantly associated with the time after onset. The latencies were influenced by the presence of CDMS (P = 0.0033), whereas the amplitudes were influenced by visual acuity (P = 0.0000). When visual acuity was included in a multifactor model, the time after onset was, however, not significantly associated with the amplitude (P = 0.8826). The mean latency of the VEPs in eyes with acute ON was significantly shorter in AMON than in ON as part of CDMS. This study provides evidence that VEP abnormality is often transitory, and that VEP often normalizes during follow-up. The diagnostic yield is increased by repeating VEP in the spontaneous course of acute ON. Visual evoked potential is a sensitive tool for revealing subclinical lesions.
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Affiliation(s)
- J L Frederiksen
- Department of Neurology, Glostrup Hospital, University of Copenhagen, Glostrup, Denmark
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28
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Affiliation(s)
- W I McDonald
- Institute of Neurology, Queen Square, London, and Moorfields Eye Hospital, City Road, London, UK
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29
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Corona-Vazquez T, Ruiz-Sandoval J, Arriada-Mendicoa N. Optic neuritis progressing to multiple sclerosis. Acta Neurol Scand 1997; 95:85-9. [PMID: 9059726 DOI: 10.1111/j.1600-0404.1997.tb00074.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We report a partially retrospective and longitudinal study of patients with optic neuritis (ON) that developed multiple sclerosis (MS). We assessed clinical features or factors that might differentiate these patients from those with ON that did not develop MS. Of the cases followed, 110 (67%) were found to have an idiopathic origin of the disease; whereas 55 (33%) were found to develop it secondary to another disease. Of the 110 idiopathic cases, 13 (12%), developed MS over an average of 2 years. The results of these patients in the laboratory analyses of blood and CSF as well as the results of the MRI and evoked potential studies, were significantly different from the ON patients without MS. We conclude that the percentage of patients with ON in our sample that developed MS is similar to that found in Japan and is relatively low in comparison to other reports.
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Affiliation(s)
- T Corona-Vazquez
- Neurology Division, Instituto Nacional de Neurología, y Neurocirugía, Maxico City, Mexico
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Evers S, Bauer B, Husstedt IW. Side-to-side differences in visual event-related potentials but not VEP in patients with multiple sclerosis: A report of three cases. Neuroophthalmology 1997. [DOI: 10.3109/01658109709044652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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31
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Meeting Report and Proceedings: Multiple Sclerosis Society of Great Britain and Northern Ireland. Mult Scler 1996. [DOI: 10.1177/135245859600200101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Trauzettel-Klosinski S, Diener HC, Dietz K, Zrenner E. The effect of oral prednisolone on visual evoked potential latencies in acute optic neuritis monitored in a prospective, randomized, controlled study. Doc Ophthalmol 1995; 91:165-79. [PMID: 8813496 DOI: 10.1007/bf01203696] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The Tübingen study of optic neuritis treatment was started in 1980 to apply new and sensitive tests for monitoring a potential therapeutical steroid effect on the course of acute optic neuritis. Visual evoked potentials were used to assess an effect of oral methylprednisolone in a randomized, controlled trial. Forty-eight patients with acute optic neuritis were treated orally either with methylprednisolone (100 mg per day initially, dosage reduction every 3 days; n = 15) or with thiamine (100 mg per day; n = 33) in the control group, 36 of them in a double-blind procedure. A comparison of the two treatment groups indicated that oral methylprednisolone resulted in a faster improvement in visual evoked potential latency in the initial phase (p = 0.015, 4 weeks after onset), but had no benefit after 12 weeks and 12 months. Follow-up showed different types of courses in the visual evoked potential latencies. The visual evoked potential latencies were correlated to other outcome variables, such as visual evoked potential amplitudes, visual acuity, Aulhorn flicker test and perimetry. We were able to handle nonmeasurable latencies in highly pathologic cases by means of ranks (taking into account censored observations).
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Affiliation(s)
- S Trauzettel-Klosinski
- Department of Pathophysiology of Vision and Neuroophthalmology, University Eye Hospital, Tübingen, Germany
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La Mantia L, Riti F, Milanese C, Salmaggi A, Eoli M, Ciano C, Avanzini G. Serial evoked potentials in multiple sclerosis bouts. Relation to steroid treatment. ITALIAN JOURNAL OF NEUROLOGICAL SCIENCES 1994; 15:333-40. [PMID: 7698890 DOI: 10.1007/bf02339929] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Serial recordings of multimodal sensory (visual, acoustic and somatosensory) evoked potentials were made in 19 relapsing-remitting Multiple Sclerosis patients enrolled in a clinical trial designed to evaluate the efficacy of dexamethasone versus high- and low-dose methylprednisolone in acute multiple sclerosis bouts. Electrophysiological and clinical evaluations were performed at the onset of therapy and until 6 months after the end of treatment. Using an arbitrary Evoked Potentials score that takes into account both latency and waveform alterations, we found a positive correlation between evoked potentials and clinical disability scores. Furthermore, different electrophysiological profiles were detected in the three therapeutic subgroups. Evoked potentials may be useful for monitoring acute Multiple Sclerosis bouts and evaluating the effect of therapy.
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Affiliation(s)
- L La Mantia
- Divisione di Neurologia, Istituto Neurologico C. Besta di Milano, Italy
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