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Upbeat Nystagmus with an Unusual Velocity-Decreasing and Increasing Waveform: a Sign of Gaze-Holding Dysfunction in the Paramedian Tracts in the Medulla? CEREBELLUM (LONDON, ENGLAND) 2023; 22:148-154. [PMID: 35133635 DOI: 10.1007/s12311-022-01376-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/29/2022] [Indexed: 02/01/2023]
Abstract
We report a patient with spontaneous upbeat nystagmus (UBN) due to an ischemic lesion involving the paramedian tract (PMT) in the medulla. Eye movement recordings, using an infrared video-oculography (VOG) system, showed that the slow phase of the nystagmus was initially velocity-decreasing but gradually became velocity-increasing. Simulation of the nystagmus with a mathematical model supports a role for the PMT in relaying premotor signals for vertical gaze holding to the cerebellum. Our model shows that the disruption in cerebellar input from PMT can lead to the velocity-increasing waveform of the nystagmus, whereas the velocity-decreasing waveform could be related to a mismatch between the innervational commands to the ocular muscles (the pulse and step) needed to hold gaze steady.
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Kim JS, Newman-Toker DE, Kerber KA, Jahn K, Bertholon P, Waterston J, Lee H, Bisdorff A, Strupp M. Vascular vertigo and dizziness: Diagnostic criteria. J Vestib Res 2022; 32:205-222. [PMID: 35367974 PMCID: PMC9249306 DOI: 10.3233/ves-210169] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This paper presents diagnostic criteria for vascular vertigo and dizziness as formulated by the Committee for the Classification of Vestibular Disorders of the Bárány Society. The classification includes vertigo/dizziness due to stroke or transient ischemic attack as well as isolated labyrinthine infarction/hemorrhage, and vertebral artery compression syndrome. Vertigo and dizziness are among the most common symptoms of posterior circulation strokes. Vascular vertigo/dizziness may be acute and prolonged (≥24 hours) or transient (minutes to < 24 hours). Vascular vertigo/dizziness should be considered in patients who present with acute vestibular symptoms and additional central neurological symptoms and signs, including central HINTS signs (normal head-impulse test, direction-changing gaze-evoked nystagmus, or pronounced skew deviation), particularly in the presence of vascular risk factors. Isolated labyrinthine infarction does not have a confirmatory test, but should be considered in individuals at increased risk of stroke and can be presumed in cases of acute unilateral vestibular loss if accompanied or followed within 30 days by an ischemic stroke in the anterior inferior cerebellar artery territory. For diagnosis of vertebral artery compression syndrome, typical symptoms and signs in combination with imaging or sonographic documentation of vascular compromise are required.
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Affiliation(s)
- Ji-Soo Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
| | - David E Newman-Toker
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Kevin A Kerber
- Department of Neurology, University of Michigan Health System, Ann Arbor, USA
| | - Klaus Jahn
- Department of Neurology Schoen Clinic Bad Aibling and German Center for Vertigo and Balance Disorders, Ludwig Maximilians University, Munich, Germany
| | | | - John Waterston
- Monash Department of Neuroscience, Alfred Hospital, Melbourne, Australia
| | - Hyung Lee
- Department of Neurology, Brain Research Institute, Keimyung University School of Medicine, Daegu, Korea
| | - Alexandre Bisdorff
- Department of Neurology, Centre Hospitalier Emile Mayrisch, Esch-sur-Alzette, Luxembourg
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Ludwig Maximilians University, Munich, Germany
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Mantokoudis G, Korda A, Zee DS, Zamaro E, Sauter TC, Wagner F, Caversaccio MD. Bruns' nystagmus revisited: A sign of stroke in patients with the acute vestibular syndrome. Eur J Neurol 2021; 28:2971-2979. [PMID: 34176187 PMCID: PMC8456911 DOI: 10.1111/ene.14997] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 06/24/2021] [Indexed: 11/29/2022]
Abstract
Objective Gaze‐evoked nystagmus (GEN) is a central sign in patients with the acute vestibular syndrome (AVS); however, discriminating between a pathological and a physiologic GEN is a challenge. Here we evaluate GEN in patients with AVS. Methods In this prospective cross‐sectional study, we used video‐oculography (VOG) to compare GEN in the light (target at 15° eccentric) in 64 healthy subjects with 47 patients seen in the emergency department (ED) who had AVS; 35 with vestibular neuritis and 12 with stroke. All patients with an initial non‐diagnostic MRI received a confirmatory, delayed MRI as a reference standard in detecting stroke. Results Healthy subjects with GEN had a time constant of centripetal drift >18 s. VOG identified pathologic GEN (time constant ≤ 18 s) in 33% of patients with vestibular strokes, specificity was 100%, accuracy was 83%. Results were equivalent to examination by a clinical expert. As expected, since all patients with GEN had a SN in straight‐ahead position, they showed the pattern of a Bruns’ nystagmus. Conclusions One third of patients with AVS due to central vestibular strokes had a spontaneous SN in straight‐ahead gaze and a pathological GEN, producing the pattern of a Bruns’ nystagmus with a shift of the null position. The localization of the side of the lesion based on the null was not consistent, presumably because the circuits underlying gaze‐holding are widespread in the brainstem and cerebellum. Nevertheless, automated quantification of GEN with VOG was specific, and accurately identified patients in the ED with AVS due to strokes.
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Affiliation(s)
- Georgios Mantokoudis
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Athanasia Korda
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - David S Zee
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ewa Zamaro
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Thomas C Sauter
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Franca Wagner
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Marco D Caversaccio
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Rucker JC, Rizzo JR, Hudson TE, Horn AKE, Buettner-Ennever JA, Leigh RJ, Optican LM. Dysfunctional mode switching between fixation and saccades: collaborative insights into two unusual clinical disorders. J Comput Neurosci 2021; 49:283-293. [PMID: 33839988 DOI: 10.1007/s10827-021-00785-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/01/2021] [Accepted: 02/24/2021] [Indexed: 11/28/2022]
Abstract
Voluntary rapid eye movements (saccades) redirect the fovea toward objects of visual interest. The saccadic system can be considered as a dual-mode system: in one mode the eye is fixating, in the other it is making a saccade. In this review, we consider two examples of dysfunctional saccades, interrupted saccades in late-onset Tay-Sachs disease and gaze-position dependent opsoclonus after concussion, which fail to properly shift between fixation and saccade modes. Insights and benefits gained from bi-directional collaborative exchange between clinical and basic scientists are emphasized. In the case of interrupted saccades, existing mathematical models were sufficiently detailed to provide support for the cause of interrupted saccades. In the case of gaze-position dependent opsoclonus, existing models could not explain the behavior, but further development provided a reasonable hypothesis for the mechanism underlying the behavior. Collaboration between clinical and basic science is a rich source of progress for developing biologically plausible models and understanding neurological disease. Approaching a clinical problem with a specific hypothesis (model) in mind often prompts new experimental tests and provides insights into basic mechanisms.
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Affiliation(s)
- Janet C Rucker
- Departments of Neurology, New York University Grossman School of Medicine, New York, NY, USA. .,Departments of Ophthalmology, New York University Grossman School of Medicine, New York, NY, USA.
| | - John-Ross Rizzo
- Departments of Neurology, New York University Grossman School of Medicine, New York, NY, USA.,Departments of Rehabilitation Medicine, New York University Grossman School of Medicine, New York, NY, USA.,Departments of Biomedical Engineering, New York University Tandon School of Engineering, New York, NY, USA.,Departments of Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, New York, NY, USA
| | - Todd E Hudson
- Departments of Neurology, New York University Grossman School of Medicine, New York, NY, USA.,Departments of Rehabilitation Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Anja K E Horn
- Department of Anatomy and Cell Biology I, Ludwig-Maximilians University, Munich, Germany
| | | | - R John Leigh
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
| | - Lance M Optican
- Laboratory of Sensorimotor Research, NEI, NIH, DHHS, Bethesda, MD, USA
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Lädrach C, Zee DS, Wyss T, Wimmer W, Korda A, Salmina C, Caversaccio MD, Mantokoudis G. Alexander's Law During High-Speed, Yaw-Axis Rotation: Adaptation or Saturation? Front Neurol 2020; 11:604502. [PMID: 33329363 PMCID: PMC7719745 DOI: 10.3389/fneur.2020.604502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 10/02/2020] [Indexed: 11/13/2022] Open
Abstract
Objective: Alexander's law (AL) states the intensity of nystagmus increases when gaze is toward the direction of the quick phase. What might be its cause? A gaze-holding neural integrator (NI) that becomes imperfect as the result of an adaptive process, or saturation in the discharge of neurons in the vestibular nuclei? Methods: We induced nystagmus in normal subjects using a rapid chair acceleration around the yaw (vertical) axis to a constant velocity of 200°/second [s] and then, 90 s later, a sudden stop to induce post-rotatory nystagmus (PRN). Subjects alternated gaze every 2 s between flashing LEDs (right/left or up/down). We calculated the change in slow-phase velocity (ΔSPV) between right and left gaze when the lateral semicircular canals (SCC) were primarily stimulated (head upright) or, with the head tilted to the side, stimulating the vertical and lateral SCC together. Results: During PRN AL occurred for horizontal eye movements with the head upright and for both horizontal and vertical components of eye movements with the head tilted. AL was apparent within just a few seconds of the chair stopping when peak SPV of PRN was reached. When slow-phase velocity of PRN faded into the range of 6-18°/s AL could no longer be demonstrated. Conclusions: Our results support the idea that AL is produced by asymmetrical responses within the vestibular nuclei impairing the NI, and not by an adaptive response that develops over time. AL was related to the predicted plane of eye rotations in the orbit based on the pattern of SCC activation.
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Affiliation(s)
- Claudia Lädrach
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital Bern, Bern, Switzerland
| | - David S Zee
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Thomas Wyss
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital Bern, Bern, Switzerland
| | - Wilhelm Wimmer
- Hearing Research Laboratory, ARTORG Center, University of Bern, Bern, Switzerland
| | - Athanasia Korda
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital Bern, Bern, Switzerland
| | - Cinzia Salmina
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital Bern, Bern, Switzerland
| | - Marco D Caversaccio
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital Bern, Bern, Switzerland
| | - Georgios Mantokoudis
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital Bern, Bern, Switzerland
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Abstract
Opsoclonus/flutter (O/F) is a rare disorder of the saccadic system. Previously, we modeled O/F that developed in a patient following abuse of anabolic steroids. That model, as in all models of the saccadic system, generates commands to make a change in eye position. Recently, we saw a patient who developed a unique form of opsoclonus following a concussion. The patient had postsaccadic ocular flutter in both directions of gaze, and opsoclonus during fixation and pursuit in the left hemifield. A new model of the saccadic system is needed to account for this gaze-position dependent O/F. We started with our prior model, which contains two key elements, mutual inhibition between inhibitory burst neurons on both sides and a prolonged reactivation time of the omnipause neurons (OPNs). We included new inputs to the OPNs from the nucleus prepositus hypoglossi and the frontal eye fields, which contain position-dependent neurons. This provides a mechanism for delaying OPN reactivation, and creating a gaze-position dependence. A simplified pursuit system was also added, the output of which inhibits the OPNs, providing a mechanism for gaze-dependence during pursuit. The rest of the model continues to generate a command to change eye position.
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Otero-Millan J, Colpak AI, Kheradmand A, Zee DS. Rebound nystagmus, a window into the oculomotor integrator. PROGRESS IN BRAIN RESEARCH 2019; 249:197-209. [DOI: 10.1016/bs.pbr.2019.04.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Hong K, Shim HM, Goh M, Jang SY, Lee S, Kim KS. Direct perturbation of neural integrator by bilateral galvanic vestibular stimulation. Med Biol Eng Comput 2016; 55:207-212. [PMID: 27108289 DOI: 10.1007/s11517-016-1502-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/28/2016] [Indexed: 11/26/2022]
Abstract
Caloric vestibular stimulation (CVS) and galvanic vestibular stimulation (GVS) act primarily on the peripheral vestibular system. Although the electrical current applied during GVS is thought to flow through peripheral vestibular organs, some current may spread into areas within the central nervous system, particularly when the bilateral galvanic vestibular stimulation (bGVS) method is used. According to Alexander's law, the magnitude of nystagmus increases with eccentric gaze movement, due to the function of the neural integrator (NI); thus, if the information for vestibular stimulation corresponds to Alexander's law, the peripheral vestibular organ is stimulated. Therefore, it would appear that if CVS results comply with Alexander's law, and bGVS results do not, the sites stimulated by bGVS are not perfectly located in the peripheral vestibular area. In our experiments on normal human subjects, the magnitude of nystagmus under CVS increased with rising gaze eccentricity in the direction that the magnitude of the nystagmus increases, and this change was found to follow Alexander's law. However, in the case of nystagmus under bGVS, results did not follow Alexander's law. In addition, study of the influences of bGVS at different current intensities on nystagmus magnitude showed that bGVS at 5 mA distorted nystagmus magnitude more than at 3 mA, which suggests bGVS acts not only on the peripheral vestibular nerves, but also on some areas of the central nervous system, particularly the NI. According to our experiments, bGVS directly affects neural integrator function.
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Affiliation(s)
- Kihwan Hong
- Biomedical Engineering Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, Korea
| | - Hyeon-Min Shim
- Department of Digital Electronics, Dong Seoul University, Seongnam, Korea
| | - Minsoo Goh
- Institute for Information and Electronics Research (IIER), Inha University, Incheon, Korea
| | - Seung-Yon Jang
- Department of Otolaryngology-Head and Neck Surgery, Inha University Hospital, Incheon, Korea
| | - Sangmin Lee
- Institute for Information and Electronics Research (IIER), Inha University, Incheon, Korea
- Department of Electronic Engineering, Inha University, Incheon, Korea
| | - Kyu-Sung Kim
- Institute for Information and Electronics Research (IIER), Inha University, Incheon, Korea.
- Department of Otolaryngology-Head and Neck Surgery, Inha University Hospital, Incheon, Korea.
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Bertolini G, Tarnutzer AA, Olasagasti I, Khojasteh E, Weber KP, Bockisch CJ, Straumann D, Marti S. Gaze holding in healthy subjects. PLoS One 2013; 8:e61389. [PMID: 23637824 PMCID: PMC3637181 DOI: 10.1371/journal.pone.0061389] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 03/08/2013] [Indexed: 12/03/2022] Open
Abstract
Eccentric gaze in darkness evokes minor centripetal eye drifts in healthy subjects, as cerebellar control sufficiently compensates for the inherent deficiencies of the brainstem gaze-holding network. This behavior is commonly described using a leaky integrator model, which assumes that eye velocity grows linearly with gaze eccentricity. Results from previous studies in patients and healthy subjects suggest caution when this assumption is applied to eye eccentricities larger than 20 degrees. To obtain a detailed characterization of the centripetal gaze-evoked drift, we recorded horizontal eye position in 20 healthy subjects. With their head fixed, they were asked to fixate a flashing dot (50 ms every 2 s)that was quasi-stationary displacing(0.5 deg/s) between ±40 deg horizontally in otherwise complete darkness. Drift velocity was weak at all angles tested. Linearity was assessed by dividing the range of gaze eccentricity in four bins of 20 deg each, and comparing the slopes of a linear function fitted to the horizontal velocity in each bin. The slopes of single subjects for gaze eccentricities of ±0−20 deg were, in median,0.41 times the slopes obtained for gaze eccentricities of ±20−40 deg. By smoothing the individual subjects' eye velocity as a function of gaze eccentricity, we derived a population of position-velocity curves. We show that a tangent function provides a better fit to the mean of these curves when large eccentricities are considered. This implies that the quasi-linear behavior within the typical ocular motor range is the result of a tuning procedure, which is optimized in the most commonly used range of gaze. We hypothesize that the observed non-linearity at eccentric gaze results from a saturation of the input that each neuron in the integrating network receives from the others. As a consequence, gaze-holding performance declines more rapidly at large eccentricities.
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Affiliation(s)
- Giovanni Bertolini
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland.
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Eye position dependency of nystagmus during constant vestibular stimulation. Exp Brain Res 2013; 226:175-82. [DOI: 10.1007/s00221-013-3423-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/15/2013] [Indexed: 10/27/2022]
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Bockisch CJ, Khojasteh E, Straumann D, Hegemann SCA. Development of eye position dependency of slow phase velocity during caloric stimulation. PLoS One 2012; 7:e51409. [PMID: 23251522 PMCID: PMC3520909 DOI: 10.1371/journal.pone.0051409] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 11/02/2012] [Indexed: 11/25/2022] Open
Abstract
The nystagmus in patients with vestibular disorders often has an eye position dependency, called Alexander’s law, where the slow phase velocity is higher with gaze in the fast phase direction compared with gaze in the slow phase direction. Alexander’s law has been hypothesized to arise either due to adaptive changes in the velocity-to-position neural integrator, or as a consequence of processing of the vestibular-ocular reflex. We tested whether Alexander’s law arises only as a consequence of non-physiologic vestibular stimulation. We measured the time course of the development of Alexander’s law in healthy humans with nystagmus caused by three types of caloric vestibular stimulation: cold (unilateral inhibition), warm (unilateral excitation), and simultaneous bilateral bithermal (one side cold, the other warm) stimulation, mimicking the normal push-pull pattern of vestibular stimulation. Alexander’s law, measured as a negative slope of the velocity versus position curve, was observed in all conditions. A reversed pattern of eye position dependency (positive slope) was found <10% of the time. The slope often changed with nystagmus velocity (cross-correlation of nystagmus speed and slope was significant in 50% of cases), and the average lag of the slope with the speed was not significantly different from zero. Our results do not support the hypothesis that Alexander’s law can only be observed with non-physiologic vestibular stimulation. Further, the rapid development of Alexander’s law, while possible for an adaptive mechanism, is nonetheless quite fast compared to most other ocular motor adaptations. These results suggest that Alexander’s law may not be a consequence of a true adaptive mechanism.
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Affiliation(s)
- Christopher J Bockisch
- Department of Otorhinolaryngology, Head & Neck Surgery, University Hospital Zürich, Zürich, Switzerland.
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