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Yun SY, Lee JH, Kim HJ, Choi JY, Kim JS. Effects of Baclofen on Central Paroxysmal Positional Downbeat Nystagmus. Cerebellum 2024:10.1007/s12311-024-01684-z. [PMID: 38498146 DOI: 10.1007/s12311-024-01684-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/09/2024] [Indexed: 03/20/2024]
Abstract
Paroxysmal positional nystagmus frequently occurs in lesions involving the cerebellum, and has been ascribed to disinhibition and enhanced canal signals during positioning due to cerebellar dysfunction. This study aims to elucidate the mechanism of central positional nystagmus (CPN) by determining the effects of baclofen on the intensity of paroxysmal positional downbeat nystagmus due to central lesions. Fifteen patients with paroxysmal downbeat CPN were subjected to manual straight head-hanging before administration of baclofen, while taking baclofen 30 mg per day for at least one week, and two weeks after discontinuation of baclofen. The maximum slow phase velocity (SPV) and time constant (TC) of the induced paroxysmal downbeat CPN were analyzed. The positional vertigo was evaluated using an 11-point numerical rating scale (0 to 10) in 9 patients. After treatment with baclofen, the median of the maximum SPV of paroxysmal downbeat CPN decreased from 30.1°/s [interquartile range (IQR) = 19.6-39.0°/s] to 15.2°/s (IQR = 11.2-22.0°/s, Wilcoxon signed rank test, p < 0.001) with the median decrement ratio at 40.2% (IQR = 28.2-50.6%). After discontinuation of baclofen, the maximum SPV re-increased to 24.6°/s (IQR = 13.1-34.4°/s, Wilcoxon signed rank test, p = 0.001) with the median increment ratio at 23.5% (IQR = 5.2-87.9%). In contrast, the TCs of paroxysmal downbeat CPN remained unchanged at approximately 3.0 s throughout the evaluation. The positional vertigo also decreased with the medication (Wilcoxon signed rank test, p = 0.020), and remained unchanged even after discontinuation of medication (Wilcoxon signed rank test, p = 0.737). The results of this study support the prior presumption that paroxysmal CPN is caused by enhanced responses of the semicircular canals during positioning due to cerebellar disinhibition. Baclofen may be tried in symptomatic patients with paroxysmal CPN.
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Affiliation(s)
- So-Yeon Yun
- Department of Neurology, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jong-Hee Lee
- Dizziness Center, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Hyo-Jung Kim
- Biomedical Research Institute, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Jeong-Yoon Choi
- Dizziness Center, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
- Department of Neurology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ji-Soo Kim
- Dizziness Center, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
- Department of Neurology, Seoul National University College of Medicine, Seoul, Republic of Korea.
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Dietrich H, Pradhan C, Heidger F, Schniepp R, Wuehr M. Downbeat nystagmus becomes attenuated during walking compared to standing. J Neurol 2022; 269:6222-6227. [PMID: 35412151 DOI: 10.1007/s00415-022-11106-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 03/24/2022] [Accepted: 03/24/2022] [Indexed: 11/28/2022]
Abstract
Downbeat nystagmus (DBN) is a common form of acquired fixation nystagmus related to vestibulo-cerebellar impairments and associated with impaired vision and postural imbalance. DBN intensity becomes modulated by various factors such as gaze direction, head position, daytime, and resting conditions. Further evidence suggests that locomotion attenuates postural symptoms in DBN. Here, we examined whether walking might analogously influence ocular-motor deficits in DBN. Gaze stabilization mechanisms and nystagmus frequency were examined in 10 patients with DBN and 10 age-matched healthy controls with visual fixation during standing vs. walking on a motorized treadmill. Despite their central ocular-motor deficits, linear and angular gaze stabilization in the vertical plane were functional during walking in DBN patients and comparable to controls. Notably, nystagmus frequency in patients was considerably reduced during walking compared to standing (p < 0.001). The frequency of remaining nystagmus during walking was further modulated in a manner that depended on the specific phase of the gait cycle (p = 0.015). These attenuating effects on nystagmus intensity during walking suggest that ocular-motor control disturbances are selectively suppressed during locomotion in DBN. This suppression is potentially mediated by locomotor efference copies that have been shown to selectively govern gaze stabilization during stereotyped locomotion in animal models.
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Affiliation(s)
- Haike Dietrich
- German Center for Vertigo and Balance Disorders, University Hospital, LMU, Munich, Germany
| | - Cauchy Pradhan
- German Center for Vertigo and Balance Disorders, University Hospital, LMU, Munich, Germany
| | - Felix Heidger
- German Center for Vertigo and Balance Disorders, University Hospital, LMU, Munich, Germany
| | - Roman Schniepp
- German Center for Vertigo and Balance Disorders, University Hospital, LMU, Munich, Germany
| | - Max Wuehr
- German Center for Vertigo and Balance Disorders, University Hospital, LMU, Munich, Germany.
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3
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Brueggemann A, Bicvic A, Goeldlin M, Kalla R, Kerkeni H, Mantokoudis G, Abegg M, Kolníková M, Mohaupt M, Bremova-Ertl T. Effects of Acetyl-DL-Leucine on Ataxia and Downbeat-Nystagmus in Six Patients With Ataxia Telangiectasia. J Child Neurol 2022; 37:20-27. [PMID: 34620022 DOI: 10.1177/08830738211028394] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND There is no authorized treatment for ataxia telangiectasia (AT). As cerebellar symptoms of storage diseases were improved by acetyl-DL-leucine (ADLL), the authors hypothesized a symptomatic and disease-modifying effect in AT upon supplementation with ADLL. METHODS Six patients were treated with ADLL 3 g/day for 1 week followed by 5g/day for 3 weeks to 1 year. Cerebellar ataxia was evaluated by validated scales. Gaze-holding, saccades and smooth pursuit were examined by video-oculography. Measurements took place at baseline, at 1 month of therapy in 5 patients, and after 6 and 12 months in 1 patient. RESULTS The Scale for Assessment and Rating of Ataxia changed from the baseline, mean, (SD, min-max) of 22.1 (5.88, 11-28.5) to 18 points (5.39, 8.5-23.5) after 1 month on medication (P = .0028). All patients demonstrated gaze-holding deficits; 3 patients had central-position downbeat-nystagmus. Mean slow-phase velocity of this nystagmus with the gaze straight-ahead changed from 5.57°/s (1.8, 3.53-6.99) to 4.7°/s (0.79, 3.97-5.56) after 1 month on treatment (1.35, -2.56-4.17) (P = .046). INTERPRETATION ADLL may improve ataxia and ocular stability in AT patients, while the molecular basis still remains to be elucidated. A multicentric, rater-blinded, phase II trial currently investigates the effects of acetyl-L-leucine in AT (NCT03759678).
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Affiliation(s)
- Adriana Brueggemann
- Department of Internal Medicine, Sonnenhofspital, Lindenhofgruppe, Bern, Switzerland.,Shares the first author place
| | - Antonela Bicvic
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland.,Shares the first author place
| | - Martina Goeldlin
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland
| | - Roger Kalla
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland
| | - Hassen Kerkeni
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland
| | - Georgios Mantokoudis
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland
| | - Mathias Abegg
- Department of Ophthalmology, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland
| | - Miriam Kolníková
- Comenius University Children's Hospital, Department of Child Neurology, Bratislava, Slovak Republic
| | - Markus Mohaupt
- Department of Internal Medicine, Sonnenhofspital, Lindenhofgruppe, Bern, Switzerland.,Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland
| | - Tatiana Bremova-Ertl
- Department of Internal Medicine, Sonnenhofspital, Lindenhofgruppe, Bern, Switzerland.,Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland.,Center for Rare Diseases, Institute for Clinical Chemistry, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland.,German Center for Vertigo and Balance Disorders, Ludwig-Maximilians University Hospital, Campus Grosshadern, Munich, Germany
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Abstract
PURPOSE OF REVIEW This review will extensively cover the clinical manifestations, causes, diagnostic evaluation, and management strategies of downbeat nystagmus (DBN). RECENT FINDINGS Historically, MRI to assess for structural lesions at the cervicomedullary junction has been the primary diagnostic test in the evaluation of DBN since the 1980s. In recent years, there is increasing awareness of nonstructural causes of DBN including gluten ataxia, nutritional deficiencies, and paraneoplastic syndromes, among others. Medical management with aminopyridines has become first-line therapy in addition to disease-specific therapies. SUMMARY DBN is a common form of acquired nystagmus and the differential diagnosis remains broad, including both benign and potentially fatal causes. For practical purposes, the causes can be categorized as structural vs. nonstructural with MRI as the ideal, initial diagnostic study to differentiate the two. General therapeutic options include pharmacotherapy to enhance Purkinje cell function, strabismus surgery or prisms to shift null points, and behavioural changes. Disease-specific treatment is necessarily broad, though a significant proportion of patients will be idiopathic.
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Affiliation(s)
- Tu M Tran
- Department of Ophthalmology and Visual Neurosciences
| | - Michael S Lee
- Department of Ophthalmology and Visual Neurosciences
- Department of Neurology
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
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Eron JN, Ogorodnikov D, Horn AKE, Yakushin SB. Adaptation of spatio-temporal convergent properties in central vestibular neurons in monkeys. Physiol Rep 2018; 6:e13750. [PMID: 30178612 PMCID: PMC6121125 DOI: 10.14814/phy2.13750] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/29/2018] [Indexed: 02/04/2023] Open
Abstract
The spatio-temporal convergent (STC) response occurs in central vestibular cells when dynamic and static inputs are activated. The functional significance of STC behavior is not fully understood. Whether STC is a property of some specific central vestibular neurons, or whether it is a response that can be induced in any neuron at some frequencies is unknown. It is also unknown how the change in orientation of otolith polarization vector (orientation adaptation) affects STC behavior. A new complex model, that includes inputs with regular and irregular discharges from both canal and otolith afferents, was applied to experimental data to determine how many convergent inputs are sufficient to explain the STC behavior as a function of frequency and orientation adaptation. The canal-otolith and otolith-only neurons were recorded in the vestibular nuclei of three monkeys. About 42% (11/26 canal-otolith and 3/7 otolith-only) neurons showed typical STC responses at least at one frequency before orientation adaptation. After orientation adaptation in side-down head position for 2 h, some canal-otolith and otolith-only neurons altered their STC responses. Thus, STC is a property of weights of the regular and irregular vestibular afferent inputs to central vestibular neurons which appear and/or disappear based on stimulus frequency and orientation adaptation. This indicates that STC properties are more common for central vestibular neurons than previously assumed. While gravity-dependent adaptation is also critically dependent on stimulus frequency and orientation adaptation, we propose that STC behavior is also linked to the neural network responsible for localized contextual learning during gravity-dependent adaptation.
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Affiliation(s)
- Julia N. Eron
- Department of NeurologyIcahn School of Medicine at Mount SinaiNew YorkNew York
| | - Dmitri Ogorodnikov
- Department of NeurologyIcahn School of Medicine at Mount SinaiNew YorkNew York
- FNND LLCElmwood ParkNew Jersey
| | - Anja K. E. Horn
- Institute of Anatomy and Cell BiologyLudwig‐Maximilians‐UniversitätMunichGermany
| | - Sergei B. Yakushin
- Department of NeurologyIcahn School of Medicine at Mount SinaiNew YorkNew York
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Spiegel R, Claassen J, Teufel J, Bardins S, Schneider E, Lehrer Rettinger N, Jahn K, da Silva FA, Hahn A, Farahmand P, Brandt T, Strupp M, Kalla R. Resting in darkness improves downbeat nystagmus: evidence from an observational study. Ann N Y Acad Sci 2017; 1375:66-73. [PMID: 27447539 DOI: 10.1111/nyas.13172] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 06/01/2016] [Accepted: 06/15/2016] [Indexed: 11/27/2022]
Abstract
Resting in an upright position during daytime decreases downbeat nystagmus (DBN). When measured in brightness only, that is, without intermitting exposure to darkness, it does not make a significant difference whether patients have previously rested in brightness or in darkness. In real-world scenarios, people are often exposed to brightness and darkness intermittently. The aim of this study was to analyze whether resting in brightness or resting in darkness was associated with a lower post-resting DBN after intermitting exposures to brightness and darkness. Eight patients were recorded with three-dimensional video-oculography in brightness and darkness conditions, each following two 2-h resting intervals under either brightness or darkness resting conditions. The dependent variable was DBN intensity, measured in mean slow phase velocity. A repeated measures ANOVA with the factors measurement condition (brightness vs. darkness), resting condition (brightness vs. darkness), and time (after first vs. second resting interval) showed a significant effect for the factor resting condition, where previous resting in darkness was associated with a significantly lower DBN relative to previous resting in brightness (P < 0.01). The clinical relevance is to advise patients with DBN to rest in darkness.
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Affiliation(s)
- Rainer Spiegel
- Division of Internal Medicine, Basel University Hospital, Basel, Switzerland
| | - Jens Claassen
- Department of Neurology, Essen University Hospital, Essen, Germany
| | - Julian Teufel
- Department of Neurology and German Center for Vertigo and Balance Disorders, University Hospital, Munich, Germany
| | - Stanislav Bardins
- Department of Neurology and German Center for Vertigo and Balance Disorders, University Hospital, Munich, Germany
| | - Erich Schneider
- Department of Neurology and German Center for Vertigo and Balance Disorders, University Hospital, Munich, Germany.,Institute of Medical Technology, Brandenburg University of Technology, Cottbus-Senftenberg, Senftenberg, Germany
| | - Nicole Lehrer Rettinger
- Department of Neurology and German Center for Vertigo and Balance Disorders, University Hospital, Munich, Germany
| | - Klaus Jahn
- Department of Neurology and German Center for Vertigo and Balance Disorders, University Hospital, Munich, Germany
| | - Fábio Anciães da Silva
- Serviço de Neurologia, Hospital Universitário Antonio Pedro, Universidade Federal Fluminense, Niteroi, Rio de Janeiro, Brazil
| | - Ales Hahn
- Ear, Nose and Throat Department of the 3rd Medical Faculty, Charles University, Prague, Czech Republic
| | - Parvis Farahmand
- Department of Medicine, Giessen University Hospital, Giessen, Germany
| | - Thomas Brandt
- Department of Neurology and German Center for Vertigo and Balance Disorders, University Hospital, Munich, Germany
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, University Hospital, Munich, Germany
| | - Roger Kalla
- Department of Neurology, Bern University Hospital, Bern, Switzerland
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Schwarz AJ, Straumann D, Tarnutzer AA. Diurnal Fluctuations of Verticality Perception - Lesser Precision Immediately after Waking up in the Morning. Front Neurol 2015; 6:195. [PMID: 26388837 PMCID: PMC4557077 DOI: 10.3389/fneur.2015.00195] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/20/2015] [Indexed: 11/30/2022] Open
Abstract
Internal estimates of direction of gravity are continuously updated by integrating vestibular, visual and proprioceptive input, and prior experience about upright position. Prolonged static roll-tilt biases perceived direction of gravity by adaptation of peripheral sensors and central structures. We hypothesized that in the morning after sleep, estimates of direction of gravity [assessed by the subjective visual vertical (SVV)] are less precise than in the evening because of adaptation to horizontal body position and lack of prior knowledge about upright position. Using a mobile SVV-measuring device, verticality perception was assessed in seven healthy human subjects on 7 days in the morning immediately after waking up and in the evening while sitting upright. Paired t-tests were applied to analyze diurnal changes in SVV trial-to-trial variability. Average SVV variability in the morning was significantly larger than in the evening (1.9 ± 0.6° vs. 0.9 ± 0.3°, p = 0.002). SVV accuracy was not significantly different (−1.2 ± 0.9° vs. −0.4 ± 0.4°, morning vs. evening, p = 0.058) and was within normal range (±2.3°) in all but one subject. A good night’s sleep has a profound effect on the brain’s ability to estimate direction of gravity. Resulting variability was significantly worse after waking up reaching values more than twice as large as in the evening while there was no significant impact on SVV accuracy. We hypothesize that lacking prior knowledge, adaptation of peripheral sensors, and lower levels of arousal and cerebral metabolism contribute to such impoverished estimates. Our observations have considerable clinical impact as they indicate an increased risk for falls and fall-related injuries in the morning.
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Affiliation(s)
| | - Dominik Straumann
- Department of Neurology, University Hospital Zurich, University of Zurich , Zurich , Switzerland
| | - Alexander A Tarnutzer
- Department of Neurology, University Hospital Zurich, University of Zurich , Zurich , Switzerland
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Bremova T, Glasauer S, Strupp M. Downbeat nystagmus: evidence for enhancement of utriculo-ocular pathways by ocular vestibular evoked myogenic potentials? Eur Arch Otorhinolaryngol 2015; 272:3575-83. [DOI: 10.1007/s00405-015-3653-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/10/2015] [Indexed: 11/26/2022]
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9
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Affiliation(s)
- Shin C Beh
- Department of Neurology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Teresa C Frohman
- Department of Neurology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Elliot M Frohman
- Department of Neurology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA; Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.
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10
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Abstract
BACKGROUND Downbeat nystagmus (DBN) is a common form of acquired fixation nystagmus with key symptoms of oscillopsia and gait disturbance. Gait disturbance could be a result of impaired visual feedback due to the involuntary ocular oscillations. Alternatively, a malfunction of cerebellar locomotor control might be involved, since DBN is considered a vestibulocerebellar disorder. METHODS Investigation of walking in 50 DBN patients (age 72 ± 11 years, 23 females) and 50 healthy controls (HS) (age 70 ± 11 years, 23 females) using a pressure sensitive carpet (GAITRite). The patient cohort comprised subjects with only ocular motor signs (DBN) and subjects with an additional limb ataxia (DBNCA). Gait investigation comprised different walking speeds and walking with eyes closed. RESULTS In DBN, gait velocity was reduced (p<0.001) with a reduced stride length (p<0.001), increased base of support (p<0.050), and increased double support (p<0.001). Walking with eyes closed led to significant gait changes in both HS and DBN. These changes were more pronounced in DBN patients (p<0.001). Speed-dependency of gait variability revealed significant differences between the subgroups of DBN and DBNCA (p<0.050). CONCLUSIONS (I) Impaired visual control caused by involuntary ocular oscillations cannot sufficiently explain the gait disorder. (II) The gait of patients with DBN is impaired in a speed dependent manner. (III) Analysis of gait variability allows distinguishing DBN from DBNCA: Patients with pure DBN show a speed dependency of gait variability similar to that of patients with afferent vestibular deficits. In DBNCA, gait variability resembles the pattern found in cerebellar ataxia.
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Affiliation(s)
- Roman Schniepp
- Department of Neurology, University of Munich, Munich, Germany
- German Center for Vertigo and Balance Disorders (DSGZ), University of Munich, Munich, Germany
- * E-mail:
| | - Max Wuehr
- German Center for Vertigo and Balance Disorders (DSGZ), University of Munich, Munich, Germany
| | - Sabrina Huth
- Department of Neurology, University of Munich, Munich, Germany
- German Center for Vertigo and Balance Disorders (DSGZ), University of Munich, Munich, Germany
| | - Cauchy Pradhan
- German Center for Vertigo and Balance Disorders (DSGZ), University of Munich, Munich, Germany
| | - Cornelia Schlick
- German Center for Vertigo and Balance Disorders (DSGZ), University of Munich, Munich, Germany
| | - Thomas Brandt
- German Center for Vertigo and Balance Disorders (DSGZ), University of Munich, Munich, Germany
- Institute for Clinical Neurosciences, University of Munich, Munich, Germany
| | - Klaus Jahn
- Department of Neurology, University of Munich, Munich, Germany
- German Center for Vertigo and Balance Disorders (DSGZ), University of Munich, Munich, Germany
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11
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Claassen J, Spiegel R, Kalla R, Faldon M, Kennard C, Danchaivijitr C, Bardins S, Rettinger N, Schneider E, Brandt T, Jahn K, Teufel J, Strupp M, Bronstein A. A randomised double-blind, cross-over trial of 4-aminopyridine for downbeat nystagmus--effects on slowphase eye velocity, postural stability, locomotion and symptoms. J Neurol Neurosurg Psychiatry 2013; 84:1392-9. [PMID: 23813743 DOI: 10.1136/jnnp-2012-304736] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE The effects of 4-aminopyridine (4-AP) on downbeat nystagmus (DBN) were analysed in terms of slow-phase velocity (SPV), stance, locomotion, visual acuity (VA), patient satisfaction and side effects using standardised questionnaires. METHODS Twenty-seven patients with DBN received 5 mg 4-AP four times a day or placebo for 3 days and 10 mg 4-AP four times a day or placebo for 4 days. Recordings were done before the first, 60 min after the first and 60 min after the last drug administration. RESULTS SPV decreased from 2.42 deg/s at baseline to 1.38 deg/s with 5 mg 4-AP and to 2.03 deg/s with 10 mg 4-AP (p<0.05; post hoc: 5 mg 4-AP: p=0.04). The rate of responders was 57%. Increasing age correlated with a 4-AP-related decrease in SPV (p<0.05). Patients improved in the 'get-up-and-go test' with 4-AP (p<0.001; post hoc: 5 mg: p=0.025; 10 mg: p<0.001). Tandem-walk time (both p<0.01) and tandem-walk error (4-AP: p=0.054; placebo: p=0.059) improved under 4-AP and placebo. Posturography showed that some patients improved with the 5 mg 4-AP dose, particularly older patients. Near VA increased from 0.59 at baseline to 0.66 with 5 mg 4-AP (p<0.05). Patients with idiopathic DBN had the greatest benefit from 4-AP. There were no differences between 4-AP and placebo regarding patient satisfaction and side effects. CONCLUSIONS 4-AP reduced SPV of DBN, improved near VA and some locomotor parameters. 4-AP is a useful medication for DBN syndrome, older patients in particular benefit from the effects of 5 mg 4-AP on nystagmus and postural stability.
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Affiliation(s)
- Jens Claassen
- Department of Neurology and German Center for Vertigo and Balance Disorders (IFBLMU), University Hospital Munich, Campus Großhadern, , Munich, Bavaria, Germany
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12
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Abstract
OPINION STATEMENT Patients with congenital and acquired forms of nystagmus are commonly encountered in clinical practice. Many report visual symptoms, such as oscillopsia and blurred vision, which can be alleviated if the nystagmus can be suppressed. Pharmacologic, optical, and surgical treatments are available, with the choice of treatment depending on the characteristics of the nystagmus and the severity of the associated visual symptoms. Downbeat nystagmus can be treated with 4-aminopyridine, 3,4-diaminopyridine, or clonazepam. Upbeat nystagmus can be reduced with memantine, 4-aminopyridine, or baclofen. Torsional nystagmus may respond to gabapentin. Acquired pendular nystagmus in patients with multiple sclerosis is often partially suppressed by gabapentin or memantine. Acquired pendular nystagmus in patients with oculopalatal tremor can respond to gabapentin, memantine, or trihexyphenidyl. Although acquired periodic alternating nystagmus is often completely suppressed by baclofen, memantine can be effective in refractory cases. Seesaw nystagmus can be reduced with alcohol, clonazepam, or memantine. Infantile nystagmus may not cause significant visual symptoms if "foveation periods" are well developed, but the nystagmus can be treated in symptomatic patients with gabapentin, memantine, acetazolamide, topical brinzolamide, contact lenses, or base-out prisms to induce convergence. Several surgical therapies have also been reported to improve infantile nystagmus syndrome (INS), but selection of the appropriate therapy requires preoperative evaluation of visual acuity and nystagmus intensity in different gaze positions. Other treatment options for nystagmus include botulinum toxin injections into the extraocular muscles or retrobulbar space. Electro-optical devices are currently being developed, in order to noninvasively negate the visual consequences of nystagmus.
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Affiliation(s)
- Matthew J Thurtell
- Department of Ophthalmology & Visual Sciences, University of Iowa, 200 Hawkins Dr PFP, Iowa City, IA, 52242, USA,
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13
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Nevin RL. Limbic encephalopathy and central vestibulopathy caused by mefloquine: a case report. Travel Med Infect Dis 2012; 10:144-51. [PMID: 22494697 DOI: 10.1016/j.tmaid.2012.03.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 02/21/2012] [Accepted: 03/21/2012] [Indexed: 10/28/2022]
Abstract
Mefloquine is a 4-methanolquinoline anti-malarial that in recent years has fallen out of favor for use as chemoprophylaxis against infection with chloroquine-resistant Plasmodium falciparum malaria owing in part to growing concerns of side effects and potential neurotoxicity. Despite over 20 years of licensed use, the pathophysiological mechanisms underlying mefloquine's neuropsychiatric and physical side effects and the clinical significance of the drug's neurotoxicity have remained poorly understood. In this report, an adverse reaction to mefloquine chemoprophylaxis is described characterized by prodromal symptoms of anxiety with subsequent development of psychosis, short-term memory impairment, confusion and personality change accompanied by complaints of disequilibrium and vertigo, with objective findings of central vestibulopathy. It is posited that these effects represent an idiosyncratic neurotoxic syndrome of progressive limbic encephalopathy and multifocal brainstem injury caused by the drug. This case provides insights into the clinical significance of mefloquine neuronal gap junction blockade and neurotoxicity demonstrated in animal models, points to recommendations for the management of affected patients including diagnostic considerations and appropriate referrals, and highlights critical implications for the continued safe use of the medication.
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Affiliation(s)
- Remington L Nevin
- Department of Preventive Medicine, Bayne-Jones Army Community Hospital, 1585 Third Street, Fort Polk, LA 71459, USA.
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Kalla R, Spiegel R, Claassen J, Bardins S, Hahn A, Schneider E, Rettinger N, Glasauer S, Brandt T, Strupp M. Comparison of 10-mg doses of 4-aminopyridine and 3,4-diaminopyridine for the treatment of downbeat nystagmus. J Neuroophthalmol 2011; 31:320-5. [PMID: 21734596 DOI: 10.1097/WNO.0b013e3182258086] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Animal experiments have demonstrated that aminopyridines increase Purkinje cell excitability, and in clinical studies, 4-aminopyridine (4-AP) and 3,4-diaminopyridine (3,4-DAP) improved downbeat nystagmus. In this double-blind, prospective, crossover study, the effects of equivalent doses of 4-AP and 3,4-DAP on the slow-phase velocity (SPV) of downbeat nystagmus were compared. METHODS Eight patients with downbeat nystagmus due to different etiologies (cerebellar degeneration [n = 1], bilateral vestibulopathy [n = 1], bilateral vestibulopathy and cerebellar degeneration [n = 1], Arnold-Chiari I malformation and cerebellar ataxia [n = 1], cryptogenic cerebellar ataxia [n = 4]) were included. They were randomly assigned to receiving a single capsule of 10 mg of 3,4-DAP or 4-AP followed by 6 days with no medication. One week later, the treatment was switched, that is, 1 single capsule (10 mg) of the other agent. Recordings with 3-dimensional video-oculography were performed before and 45 and 90 minutes after drug administration. RESULTS Both medications had a significant effect throughout time (pre vs post 45 vs post 90) (F() = 8.876; P < 0.01). Following the administration of 3,4-DAP, mean slow velocity decreased from -5.68°/s (pre) to -3.29°/s (post 45) to -2.96°/s (post 90) (pre vs post 45/post 90 P < 0.01). In 4-AP, the mean SPV decreased from -6.04°/s (pre) to -1.58°/s (post 45) to -1.21°/s (post 90) (pre vs post 45/post 90 P < 0.00001). Both after 45 and after 90, the mean SPVs were significantly lower for 4-AP than for 3,4-DAP (P < 0.05). None of the patients reported serious side effects. CONCLUSION Based on these results, 10-mg doses of 4-AP lead to a more pronounced decrease of the SPV of downbeat nystagmus than do equivalent doses of 3,4-DAP.
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