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Marcelli V, Giannoni B, Volpe G, Faralli M, Fetoni AR, Pettorossi VE. Downbeat nystagmus: a clinical and pathophysiological review. Front Neurol 2024; 15:1394859. [PMID: 38854962 PMCID: PMC11157062 DOI: 10.3389/fneur.2024.1394859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 04/29/2024] [Indexed: 06/11/2024] Open
Abstract
Downbeat nystagmus (DBN) is a neuro-otological finding frequently encountered by clinicians dealing with patients with vertigo. Since DBN is a finding that should be understood because of central vestibular dysfunction, it is necessary to know how to frame it promptly to suggest the correct diagnostic-therapeutic pathway to the patient. As knowledge of its pathophysiology has progressed, the importance of this clinical sign has been increasingly understood. At the same time, clinical diagnostic knowledge has increased, and it has been recognized that this sign may occur sporadically or in association with others within defined clinical syndromes. Thus, in many cases, different therapeutic solutions have become possible. In our work, we have attempted to systematize current knowledge about the origin of this finding, the clinical presentation and current treatment options, to provide an overview that can be used at different levels, from the general practitioner to the specialist neurologist or neurotologist.
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Affiliation(s)
- Vincenzo Marcelli
- Audiology and Vestibology Unit, Department of ENT, Ospedale del Mare, ASL Napoli 1 Centro, Napoli, Italy
- Department of Neuroscience, Reproductive Science and Dentistry, Section of Audiology, University of Naples ‘’Federico II’’, Napoli, Italy
| | - Beatrice Giannoni
- Department of Neuroscience, Psychology, Drug’s Area and Child’s Health, University of Florence, Florence, Italy
| | - Giampiero Volpe
- Department of Neurology, Ospedale San Luca di Vallo della Lucania, ASL Salerno, Salerno, Italy
| | - Mario Faralli
- Department of ENT, University of Perugia, Perugia, Italy
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Anna Rita Fetoni
- Department of Neuroscience, Reproductive Science and Dentistry, Section of Audiology, University of Naples ‘’Federico II’’, Napoli, Italy
| | - Vito E. Pettorossi
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
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Smalling S, Roberts J, Hendrick K, Gray M, Wyrwa JM. Vestibular Testing and Impairments in Postoperative Pediatric Cerebellar Mutism Syndrome: A Case Series. Pediatr Neurol 2024; 154:15-19. [PMID: 38447508 DOI: 10.1016/j.pediatrneurol.2024.01.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 03/08/2024]
Abstract
BACKGROUND Postoperative pediatric cerebellar mutism syndrome (CMS) may occur following a process affecting the posterior cranial fossa. Recent evidence demonstrates disabling and potentially lasting motor components of this syndrome, including ataxia, hemiparesis, and oculomotor dysfunction. These impairments may contribute to vestibular deficits. METHODS This case series contributes data to quantify vestibular dysfunction in postoperative CMS. The pair consisted of one female and one male. RESULTS Vestibular testing demonstrated both peripheral and central dysfunction. CONCLUSIONS Given these findings, a thorough vestibular assessment may be indicated as part of a comprehensive evaluation following a postoperative CMS diagnosis. Further research is needed to understand the pathophysiology, treatment, and long-term outcomes of postoperative pediatric CMS.
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Affiliation(s)
- Stephanie Smalling
- Department of Physical Therapy, Children's Hospital Colorado, Aurora, Colorado
| | - Jeremy Roberts
- Department of Physical Medicine & Rehabilitation, Department of Pediatric Rehabilitation, Children's Hospital Colorado, University of Colorado, Aurora, Colorado.
| | - Karen Hendrick
- Department of Audiology, Children's Hospital Colorado, Aurora, Colorado
| | - Margot Gray
- Department of Physical Therapy, Children's Hospital Colorado, Aurora, Colorado
| | - Jordan M Wyrwa
- Department of Physical Medicine & Rehabilitation, Department of Pediatric Rehabilitation, Children's Hospital Colorado, University of Colorado, Aurora, Colorado
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3
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Duvieusart B, Leung TS, Koohi N, Kaski D. Digital biomarkers from gaze tests for classification of central and peripheral lesions in acute vestibular syndrome. Front Neurol 2024; 15:1354041. [PMID: 38595848 PMCID: PMC11003708 DOI: 10.3389/fneur.2024.1354041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/29/2024] [Indexed: 04/11/2024] Open
Abstract
Acute vestibular syndrome (AVS) is characterised by a sudden vertigo, gait instability, nausea and nystagmus. Accurate and rapid triage of patients with AVS to differentiate central (potentially sinister) from peripheral (usually benign) root causes is a challenge faced across emergency medicine settings. While there exist bedside exams which can reliably differentiate serious cases, they are underused due to clinicians' general unfamiliarity and low confidence interpreting results. Nystagmus is a fundamental part of AVS and can facilitate triaging, but identification of relevant characteristics requires expertise. This work presents two quantitative digital biomarkers from nystagmus analysis, which capture diagnostically-relevant information. The directionality biomarker evaluates changes in direction to differentiate spontaneous and gaze-evoked (direction-changing) nystagmus, while the intensity differential biomarker describes changes in intensity across eccentric gaze tests. In order to evaluate biomarkers, 24 sets of three gaze tests (left, right, and primary) are analysed. Both novel biomarkers were found to perform well, particularly directionality which was a perfect classifier. Generally, the biomarkers matched or eclipsed the performance of quantitative nystagmus features found in the literature. They also surpassed the performance of a support vector machine classifier trained on the same dataset, which achieved an accuracy of 75%. In conclusion, these biomarkers simplify the diagnostic process for non-specialist clinicians, bridging the gap between emergency care and specialist evaluation, ultimately benefiting patients with AVS.
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Affiliation(s)
- Benjamin Duvieusart
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
- SENSE Research Unit, Department of Clinical and Movement Neurosciences, University College London, London, United Kingdom
| | - Terence S. Leung
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Nehzat Koohi
- SENSE Research Unit, Department of Clinical and Movement Neurosciences, University College London, London, United Kingdom
| | - Diego Kaski
- SENSE Research Unit, Department of Clinical and Movement Neurosciences, University College London, London, United Kingdom
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Bastani PB, Rieiro H, Badihian S, Otero‐Millan J, Farrell N, Parker M, Newman‐Toker D, Zhu Y, Saber Tehrani A. Quantifying Induced Nystagmus Using a Smartphone Eye Tracking Application (EyePhone). J Am Heart Assoc 2024; 13:e030927. [PMID: 38226513 PMCID: PMC10926800 DOI: 10.1161/jaha.123.030927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Accepted: 12/10/2023] [Indexed: 01/17/2024]
Abstract
BACKGROUND There are ≈5 million annual dizziness visits to US emergency departments, of which vestibular strokes account for over 250 000. The head impulse, nystagmus, and test of skew eye examination can accurately distinguish vestibular strokes from peripheral dizziness. However, the eye-movement signs are subtle, and lack of familiarity and difficulty with recognition of abnormal eye movements are significant barriers to widespread emergency department use. To break this barrier, we sought to assess the accuracy of EyePhone, our smartphone eye-tracking application, for quantifying nystagmus. METHODS AND RESULTS We prospectively enrolled healthy volunteers and recorded the velocity of induced nystagmus using a smartphone eye-tracking application (EyePhone) and then compared the results with video oculography (VOG). Following a calibration protocol, the participants viewed optokinetic stimuli with incremental velocities (2-12 degrees/s) in 4 directions. We extracted slow phase velocities from EyePhone data in each direction and compared them with the corresponding slow phase velocities obtained by the VOG. Furthermore, we calculated the area under the receiver operating characteristic curve for nystagmus detection by EyePhone. We enrolled 10 volunteers (90% men) with an average age of 30.2±6 years. EyePhone-recorded slow phase velocities highly correlated with the VOG recordings (r=0.98 for horizontal and r=0.94 for vertical). The calibration significantly increased the slope of linear regression for horizontal and vertical slow phase velocities. Evaluating the EyePhone's performance using VOG data with a 2 degrees/s threshold showed an area under the receiver operating characteristic curve of 0.87 for horizontal and vertical nystagmus detection. CONCLUSIONS We demonstrated that EyePhone could accurately detect and quantify optokinetic nystagmus, similar to the VOG goggles.
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Affiliation(s)
- Pouya B. Bastani
- Department of NeurologyJohns Hopkins University School of MedicineBaltimoreMDUSA
- Armstrong Institute Center for Diagnostic ExcellenceBaltimoreMDUSA
| | - Hector Rieiro
- Department of NeurologyJohns Hopkins University School of MedicineBaltimoreMDUSA
- Armstrong Institute Center for Diagnostic ExcellenceBaltimoreMDUSA
| | - Shervin Badihian
- Armstrong Institute Center for Diagnostic ExcellenceBaltimoreMDUSA
- Neurological Institute, Cleveland ClinicClevelandOHUSA
| | - Jorge Otero‐Millan
- Herbert Wertheim School of Optometry and Vision ScienceUniversity of CaliforniaBerkeleyCAUSA
| | - Nathan Farrell
- Department of NeurologyJohns Hopkins University School of MedicineBaltimoreMDUSA
- Armstrong Institute Center for Diagnostic ExcellenceBaltimoreMDUSA
| | - Max Parker
- Department of Neurology, NYU Langone HealthNew YorkNYUSA
| | - David Newman‐Toker
- Department of NeurologyJohns Hopkins University School of MedicineBaltimoreMDUSA
- Armstrong Institute Center for Diagnostic ExcellenceBaltimoreMDUSA
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public HealthBaltimoreMDUSA
| | - Yuxin Zhu
- Department of NeurologyJohns Hopkins University School of MedicineBaltimoreMDUSA
- Armstrong Institute Center for Diagnostic ExcellenceBaltimoreMDUSA
- Department of BiostatisticsJohns Hopkins University Bloomberg School of Public HealthBaltimoreMDUSA
| | - Ali Saber Tehrani
- Department of NeurologyJohns Hopkins University School of MedicineBaltimoreMDUSA
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Strupp M, Bisdorff A, Furman J, Hornibrook J, Jahn K, Maire R, Newman-Toker D, Magnusson M. Acute unilateral vestibulopathy/vestibular neuritis: Diagnostic criteria. J Vestib Res 2022; 32:389-406. [PMID: 35723133 PMCID: PMC9661346 DOI: 10.3233/ves-220201] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This paper describes the diagnostic criteria for Acute Unilateral Vestibulopathy (AUVP), a synonym for vestibular neuritis, as defined by the Committee for the Classification of Vestibular Disorders of the Bárány Society. AUVP manifests as an acute vestibular syndrome due to an acute unilateral loss of peripheral vestibular function without evidence for acute central or acute audiological symptoms or signs. This implies that the diagnosis of AUVP is based on the patient history, bedside examination, and, if necessary, laboratory evaluation. The leading symptom is an acute or rarely subacute onset of spinning or non-spinning vertigo with unsteadiness, nausea/vomiting and/or oscillopsia. A leading clinical sign is a spontaneous peripheral vestibular nystagmus, which is direction-fixed and enhanced by removal of visual fixation with a trajectory appropriate to the semicircular canal afferents involved (generally horizontal-torsional). The diagnostic criteria were classified by the committee for four categories: 1. "Acute Unilateral Vestibulopathy", 2. "Acute Unilateral Vestibulopathy in Evolution", 3. "Probable Acute Unilateral Vestibulopathy" and 4. "History of Acute Unilateral Vestibulopathy". The specific diagnostic criteria for these are as follows:"Acute Unilateral Vestibulopathy": A) Acute or subacute onset of sustained spinning or non-spinning vertigo (i.e., an acute vestibular syndrome) of moderate to severe intensity with symptoms lasting for at least 24 hours. B) Spontaneous peripheral vestibular nystagmus with a trajectory appropriate to the semicircular canal afferents involved, generally horizontal-torsional, direction-fixed, and enhanced by removal of visual fixation. C) Unambiguous evidence of reduced VOR function on the side opposite the direction of the fast phase of the spontaneous nystagmus. D) No evidence for acute central neurological, otological or audiological symptoms. E) No acute central neurological signs, namely no central ocular motor or central vestibular signs, in particular no pronounced skew deviation, no gaze-evoked nystagmus, and no acute audiologic or otological signs. F) Not better accounted for by another disease or disorder."Acute Unilateral Vestibulopathy in Evolution": A) Acute or subacute onset of sustained spinning or non-spinning vertigo with continuous symptoms for more than 3 hours, but not yet lasting for at least 24 h hours, when patient is seen; B) - F) as above. This category is useful for diagnostic reasons to differentiate from acute central vestibular syndromes, to initiate specific treatments, and for research to include patients in clinical studies."Probable Acute Unilateral Vestibulopathy": Identical to AUVP except that the unilateral VOR deficit is not clearly observed or documented."History of acute unilateral vestibulopathy": A) History of acute or subacute onset of vertigo lasting at least 24 hours and slowly decreasing in intensity. B) No history of simultaneous acute audiological or central neurological symptoms. C) Unambiguous evidence of unilaterally reduced VOR function. D) No history of simultaneous acute central neurological signs, namely no central ocular motor or central vestibular signs and no acute audiological or otological signs. E) Not better accounted for by another disease or disorder. This category allows a diagnosis in patients presenting with a unilateral peripheral vestibular deficit and a history of an acute vestibular syndrome who are examined well after the acute phase.It is important to note that there is no definite test for AUVP. Therefore, its diagnosis requires the exclusion of central lesions as well as a variety of other peripheral vestibular disorders. Finally, this consensus paper will discuss other aspects of AUVP such as etiology, pathophysiology and laboratory examinations if they are directly relevant to the classification criteria.
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Affiliation(s)
- Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Hospital of the Ludwig Maximilians University, Munich, Marchioninistrasse, Munich, Germany,Corresponding author: Michael Strupp, MD, FRCP, FAAN, FANA, FEAN, Dept. of Neurology and German Center for Vertigo and Balance Disorders, Hospital of the Ludwig Maximilians University, Munich, Marchioninistrasse 15, 81377 Munich, Germany. Tel.: +49 89 44007 3678; Fax: +49 89 44007 6673; E-mail:
| | - Alexandre Bisdorff
- Clinique du Vertige, Centre Hospitalier Emile Mayrisch, Esch-sur-Alzette, Luxembourg
| | - Joseph Furman
- Department of Otolaryngology, Neurology, Bioengineering and Physical Therapy, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jeremy Hornibrook
- Departments of Otolaryngology - Head and Neck Surgery, Christchurch Hospital, University of Canterbury and University of Otago, Christchurch, New Zealand
| | - Klaus Jahn
- Department of Neurology, Schoen Clinic Bad Aibling, Bad Aibling, Germany and German Center for Vertigo and Balance Disorders, Ludwig-Maximilians University, Campus Grosshadern, Munich, Germany
| | - Raphael Maire
- Department of Otorhinolaryngology/Head & Neck Surgery, Lausanne University Hospital, Lausanne, Switzerland
| | - David Newman-Toker
- Ophthalmology, Otolaryngology and Emergency Medicine, The Johns Hopkins University School of Medicine, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Måns Magnusson
- Department of Otorhinolaryngology, Lund University, Lund, Sweden
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Ozawa M, Suzuki Y, Nomura T. Stochastic Physiological Gaze-Evoked Nystagmus With Slow Centripetal Drift During Fixational Eye Movements at Small Gaze Eccentricities. Front Hum Neurosci 2022; 16:842883. [PMID: 35634205 PMCID: PMC9133340 DOI: 10.3389/fnhum.2022.842883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
Involuntary eye movement during gaze (GZ) fixation, referred to as fixational eye movement (FEM), consists of two types of components: a Brownian motion like component called drifts-tremor (DRT) and a ballistic component called microsaccade (MS) with a mean saccadic amplitude of about 0.3° and a mean inter-MS interval of about 0.5 s. During GZ fixation in healthy people in an eccentric position, typically with an eccentricity more than 30°, eyes exhibit oscillatory movements alternating between centripetal drift and centrifugal saccade with a mean saccadic amplitude of about 1° and a period in the range of 0.5–1.0 s, which has been known as the physiological gaze-evoked nystagmus (GEN). Here, we designed a simple experimental paradigm of GZ fixation on a target shifted horizontally from the front-facing position with fewer eccentricities. We found a clear tendency of centripetal DRT and centrifugal MS as in GEN, but with more stochasticity and with slower drift velocity compared to GEN, even during FEM at GZ positions with small eccentricities. Our results showed that the target shift-dependent balance between DRT and MS achieves the GZ bounded around each of the given targets. In other words, GZ relaxes slowly with the centripetal DRT toward the front-facing position during inter-MS intervals, as if there always exists a quasi-stable equilibrium posture in the front-facing position, and MS actions pull GZ intermittently back to the target position in the opposite direction to DRT.
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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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Brune AJ, Eggenberger ER. The Outpatient Approach to Dizziness. Semin Neurol 2021; 41:771-780. [PMID: 34826878 DOI: 10.1055/s-0041-1726369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The evaluation of the dizzy patient is complicated by many common pitfalls. The patient's description of symptoms and the standard neurologic examination are often nonspecific or unrevealing, and neuroimaging is most often normal. Over the past several years, research has demonstrated that a refocusing of history taking results in more reliable and diagnostically helpful information. This can guide a targeted expansion of the exam, often with an emphasis on eye movements.
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Affiliation(s)
- Anthony J Brune
- Department of Neuro-ophthalmology and Vestibular Neurology, Institute for Neuroscience Memorial Healthcare, Owosso, Michigan
| | - Eric R Eggenberger
- Department of Ophthalmology, Neurology and Neurosurgery, Mayo Clinic Florida, Jacksonville, Florida
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9
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Tran TM, Lee MS, McClelland CM. Downbeat nystagmus: a clinical review of diagnosis and management. Curr Opin Ophthalmol 2021; 32:504-514. [PMID: 34456290 DOI: 10.1097/icu.0000000000000802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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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Lewis RF, Strupp M. Editorial: Vestibular Contributions to Health and Disease, Volume II-Dedicated to Bernard Cohen. Front Neurol 2021; 12:760822. [PMID: 34659102 PMCID: PMC8517110 DOI: 10.3389/fneur.2021.760822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 09/01/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Richard F Lewis
- Departments of Otolaryngology and Neurology and Harvard Medical School, Boston, MA, United States.,Jenks Vestibular Diagnostic and Physiology Laboratories, Massachusetts Eye and Ear, Boston, MA, United States
| | - Michael Strupp
- Department of Neurology, Ludwig Maximilians University, Munich, Germany.,German Center for Vertigo and Balance Disorders, Munich, Germany
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Shemesh AA, Kocoglu K, Akdal G, Ala RT, Halmagyi GM, Zee DS, Otero-Millan J. Modeling the interaction among three cerebellar disorders of eye movements: periodic alternating, gaze-evoked and rebound nystagmus. J Comput Neurosci 2021; 49:295-307. [PMID: 34003422 PMCID: PMC9169448 DOI: 10.1007/s10827-021-00790-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 04/28/2021] [Accepted: 05/04/2021] [Indexed: 10/21/2022]
Abstract
A woman, age 44, with a positive anti-YO paraneoplastic cerebellar syndrome and normal imaging developed an ocular motor disorder including periodic alternating nystagmus (PAN), gaze-evoked nystagmus (GEN) and rebound nystagmus (RN). During fixation there was typical PAN but changes in gaze position evoked complex, time-varying oscillations of GEN and RN. To unravel the pathophysiology of this unusual pattern of nystagmus, we developed a mathematical model of normal function of the circuits mediating the vestibular-ocular reflex and gaze-holding including their adaptive mechanisms. Simulations showed that all the findings of our patient could be explained by two, small, isolated changes in cerebellar circuits: reducing the time constant of the gaze-holding integrator, producing GEN and RN, and increasing the gain of the vestibular velocity-storage positive feedback loop, producing PAN. We conclude that the gaze- and time-varying pattern of nystagmus in our patient can be accounted for by superposition of one model that produces typical PAN and another model that produces typical GEN and RN, without requiring a new oscillator in the gaze-holding system or a more complex, nonlinear interaction between the two models. This analysis suggest a strategy for uncovering gaze-evoked and rebound nystagmus in the setting of a time-varying nystagmus such as PAN. Our results are also consistent with current ideas of compartmentalization of cerebellar functions for the control of the vestibular velocity-storage mechanism (nodulus and ventral uvula) and for holding horizontal gaze steady (the flocculus and tonsil).
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Affiliation(s)
- Ari A Shemesh
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Koray Kocoglu
- Department of Neurosciences, Institute of Health Sciences, Dokuz Eylül University, İzmir, Turkey
| | - Gülden Akdal
- Department of Neurosciences, Institute of Health Sciences, Dokuz Eylül University, İzmir, Turkey
- Department of Neurology, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
| | - Rahmi Tümay Ala
- Department of Neurology, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
| | - G Michael Halmagyi
- Department of Neurology, Royal Prince Alfred Hospital and University of Sydney, Sydney, Australia
| | - David S Zee
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Departments of Ophthalmology, Otolaryngology-Head and Neck Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jorge Otero-Millan
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- School of Optometry, University of California Berkeley, Berkeley, CA, USA.
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Abstract
While the majority of vestibular disorders may be diagnosed solely on clinical grounds, a variety of clinical scenarios exist in which objective functional assessment of the vestibular system provides data that facilitate diagnosis and treatment decisions. There exists a veritable armamentarium of sophisticated vestibular test modalities, including videonystagmography, rotary chair testing, video head impulse testing, and vestibular-evoked myogenic potentials. This article aims to help clinicians apply an accessible decision-making rubric to identify the clinical scenarios that may and may not benefit from data derived from specific vestibular function tests.
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Affiliation(s)
- Steven A Zuniga
- Department of Otolaryngology-Head and Neck Surgery, University of Minnesota, 420 Delaware Street, MMC 396, Minneapolis, MN 55455, USA.
| | - Meredith E Adams
- Department of Otolaryngology-Head and Neck Surgery, University of Minnesota, 420 Delaware Street, MMC 396, Minneapolis, MN 55455, USA
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Maximizing Effectiveness of Examination of Patients With Acute Dizziness in the Emergency Department. JOURNAL OF ACUTE CARE PHYSICAL THERAPY 2021. [DOI: 10.1097/jat.0000000000000169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Grzesiak M, Carender W, Basura GJ. Posttraumatic Dizziness: Navigating the Maze Towards Accurate Vestibular Diagnosis and Treatment. Otol Neurotol 2021; 42:e573-e578. [PMID: 33967250 DOI: 10.1097/mao.0000000000003035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Highlight the importance of establishing a differential diagnosis to identify and treat multiple origins of dizziness in a patient following traumatic brain injury (TBI). PATIENT 73-year-old man with TBI and temporal bone fracture developed posttraumatic bilateral multiple canal benign paroxysmal positional vertigo (BPPV). INTERVENTION Multi-disciplinary diagnostic evaluation and vestibular rehabilitation (VR) treatment focused on canalith repositioning maneuvers (CRMs) and central adaptation. MAIN OUTCOME MEASURES Diagnostic imaging, audiometric testing, clinical evaluation including video recordings of patterns of nystagmus, Dizziness Handicap Inventory (DHI). RESULTS Systematic clinical examination identified multiple semicircular canal BPPV in addition to a suspected underlying unilateral hypofunction. Treatment focused on the appropriate CRMs and adaptation exercises. DHI scores improved significantly and patient returned to work and recreational activities. CONCLUSION This Clinical Capsule Report highlights the importance of a comprehensive clinical evaluation of the TBI patient with dizziness when making an accurate diagnosis and treatment plan. Due to the complexity of differentiating between multiple canal BPPV in addition to other central and vestibular disorders, it is imperative for the clinician to have a clear understanding of nystagmus patterns for multicanal BPPV as well as other vestibular pathology.
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Affiliation(s)
- Melissa Grzesiak
- Department of Otolaryngology/Head and Neck Surgery, Michigan Balance-Vestibular Testing and Rehabilitation
- Division of Otology/Neurotology-Skull Base Surgery, Department of Otolaryngology/Head and Neck Surgery, Michigan Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Wendy Carender
- Department of Otolaryngology/Head and Neck Surgery, Michigan Balance-Vestibular Testing and Rehabilitation
- Division of Otology/Neurotology-Skull Base Surgery, Department of Otolaryngology/Head and Neck Surgery, Michigan Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Gregory J Basura
- Division of Otology/Neurotology-Skull Base Surgery, Department of Otolaryngology/Head and Neck Surgery, Michigan Medicine, The University of Michigan, Ann Arbor, Michigan
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Abstract
PURPOSE OF REVIEW Vestibular testing, both at the bedside and in the laboratory, is often critical in diagnosing patients with symptoms of vertigo, dizziness, unsteadiness, and oscillopsia. This article introduces readers to core concepts, as well as recent advances, in bedside and instrumented vestibular assessments. RECENT FINDINGS Vestibular testing has improved immensely in the past 2 decades. While history and bedside testing is still the primary method of differential diagnosis in patients with dizziness, advances in technology such as the ocular vestibular-evoked myogenic potential test for superior canal dehiscence and the video head impulse test for vestibular neuritis have capabilities that go far beyond the bedside examination. Current vestibular testing now allows clinicians to test all five vestibular sensors in the inner ear. SUMMARY Contemporary vestibular testing technology can now assess the entire vestibular periphery. Relatively subtle conditions, such as superior canal dehiscence or a subtle vestibular neuritis, can now be diagnosed with far greater certainty.
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Bruns nystagmus occurring after resection of a giant cerebellopontine angle acoustic neuroma. Neurochirurgie 2020; 67:500-502. [PMID: 33276002 DOI: 10.1016/j.neuchi.2020.11.007] [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: 08/03/2020] [Revised: 09/22/2020] [Accepted: 11/21/2020] [Indexed: 11/21/2022]
Abstract
Bruns Nystagmus is defined as a coarse, high-amplitude horizontal nystagmus with low oscillatory frequency as the patient looks towards the side of the lesion and a fine, low-amplitude, high- frequency primary-position nystagmus that increases as the patient looks opposite to the side of the lesion. It is usually associated with large tumors of the Cerebellopontine angle that causes significant brainstem distortion, compression of the flocculus and/or vestibulocerebellum. Here, we report a case of Bruns Nystagmus (BN) occurring as a new postoperative finding after resection of a giant cerebellopontine angle acoustic neuroma despite complete surgical resection, along with a review of the literature concerning the mechanisms of BN.
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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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Carmona S, Zalazar G, Dachesky I. Abecedario del examen vestibuloespinal. Revisión bibliográfica. REVISTA ORL 2020. [DOI: 10.14201/orl.23214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Introducción y objetivo: Durante las largas cuarentenas impuestas en el mundo por la pandemia de COVID-19 los médicos hemos empezado a usar con mayor asiduidad la modalidad de consulta virtual. La neurootología no ha sido una excepción en este contexto y usando el mecanismo de las videollamadas hemos podido dar atención y contención a un buen número de pacientes durante este período. Por esta razón y basados en la experiencia singular de este periodo, hemos diseñado un examen sistemático, basado en pruebas vestíbulo-espinales simples y presentadas en forma nemotécnica (abecedario). Sobre la base de nuestra experiencia y con una revisión de la literatura se intenta demostrar la etiología y topografía vestibular de los hallazgos. Método: Revisión narrativa. Para la búsqueda de la bibliografía se utilizó la metodología de revisión sistemática de documentos en metabuscadores y bases de datos. Periodo analizado del 2001 al 2019, en diversas revistas científicas. Resultados: El examen se dividió en cuatro pasos de acuerdo con las cuatro primeras letras del alfabeto: Ataxia (gradación), Bárány (desviación de los índices), Cefálico (tilt o inclinación cefálica de la cabeza en relación con el tronco) y Desviación (desviación oblicua de los ojos Test de skew). Discusión: Se plantea el uso de la mnemotecnia abecedario para ordenar el examen vestíbulo espinal en los pacientes con afección del sistema vestibular, de manera simple y práctica, permitiendo la modalidad virtual. Conclusiones: Este sencillo abecedario vestíbulo-espinal permite, asociado a un interrogatorio exhaustivo, realizar un examen vestibular eficaz por medios virtuales, separar eficazmente lesiones centrales de periféricas en cuadros vestibulares agudos con alta sensibilidad y especificidad y finalmente hacer un topodiagnóstico del lado de lesión vestibular.
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Abstract
BACKGROUND Eye movements are one of the most complex motor functions of the central nervous system (CNS). Eye movement disorders including nystagmus occur in diseases of the CNS and the vestibular system. A systematic clinical examination often allows a topodiagnostic classification of the lesion. OBJECTIVE The basics of eye movements, the role of the cerebellum, the clinical examination of the oculomotor system, and the most important forms of nystagmus and their diagnostic implications are described. MATERIALS AND METHODS A literature analysis assessing eye movements, cerebellar control of eye movements, clinical examination of eye movement, and nystagmus was performed. RESULTS In disorders of eye movement, diseases of the oculomotor cranial nerves and the central nervous structures are to be distinguished from diseases of the orbit, eye muscles, and motor end plates. The former result in cranial nerve-related paralysis of extraocular muscles, disturbances of saccadic and smooth pursuit eye movements, vertical or horizontal gaze palsy, internuclear ophthalmoplegia, or impaired gaze holding. Nystagmus in combination with other disturbances of ocular movement is highly related to a lesion within the CNS. Intense nystagmus with a rotatory component that decreases during fixation usually has a peripheral vestibular cause. CONCLUSION Clinical examination of eye movements and nystagmus enables the diagnosis of typical eye movement disorders with a strong relation to distinct lesions of the CNS or the peripheral vestibular pathway.
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Abstract
Purpose
Sport-related concussion is a significant public health concern that requires a multidisciplinary team to appropriately manage. Athletes often report dizziness and imbalance following concussion, and these symptoms can predict increased time to recover. Vestibular diagnostic evaluations provide important information regarding the athlete's oculomotor, gaze stability, and balance function in order to identify deficits for rehabilitation. These measures also describe objective function helpful for determining when an athlete is ready to return to play. The purpose of this clinical focus article is to provide background on the current understanding of the effects of concussion on the peripheral and central vestibular system, as well as information on a protocol that can be used for acute concussion assessment. Case studies describing 3 common postconcussion presentations will highlight the usefulness of this protocol.
Conclusion
Sport-related concussion is a highly visible disorder with many symptoms that may be evaluated in the vestibular clinic. A thoughtful protocol evaluating the typical presentation of these patients may help guide the multidisciplinary team in determining appropriate management and clearance for return to sport.
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Eggers SD, Bisdorff A, von Brevern M, Zee DS, Kim JS, Perez-Fernandez N, Welgampola MS, Della Santina CC, Newman-Toker DE. Classification of vestibular signs and examination techniques: Nystagmus and nystagmus-like movements. J Vestib Res 2019; 29:57-87. [PMID: 31256095 PMCID: PMC9249296 DOI: 10.3233/ves-190658] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This paper presents a classification and definitions for types of nystagmus and other oscillatory eye movements relevant to evaluation of patients with vestibular and neurological disorders, formulated by the Classification Committee of the Bárány Society, to facilitate identification and communication for research and clinical care. Terminology surrounding the numerous attributes and influencing factors necessary to characterize nystagmus are outlined and defined. The classification first organizes the complex nomenclature of nystagmus around phenomenology, while also considering knowledge of anatomy, pathophysiology, and etiology. Nystagmus is distinguished from various other nystagmus-like movements including saccadic intrusions and oscillations. View accompanying videos at http://www.jvr-web.org/ICVD.html
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Affiliation(s)
| | - Alexandre Bisdorff
- Department of Neurology, Centre Hospitalier Emile Mayrisch, Esch-sur-Alzette, Luxembourg
| | - Michael von Brevern
- Private Practice of Neurology and Department of Neurology, Charité, Berlin, Germany
| | - David S. Zee
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ji-Soo Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seoul, Korea
| | | | - Miriam S. Welgampola
- Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Central Clinical School, University of Sydney, Sydney, Australia
| | - Charles C. Della Santina
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David E. Newman-Toker
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Nistagmo. Neurologia 2019. [DOI: 10.1016/s1634-7072(18)41585-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
BACKGROUND AND PURPOSE Physical therapists caring for patients with neurologic or vestibular disorders must routinely examine and characterize nystagmus and other oscillatory eye movements. Often, the diagnosis hinges on proper interpretation of the nystagmus pattern. This requires understanding the terminology surrounding the numerous attributes and influencing factors of nystagmus, a systematic approach to the examination, and a classification structure that guides practitioners to the specific nystagmus type and subsequent evaluation and management. SUMMARY OF KEY POINTS Nystagmus is an involuntary, rapid, rhythmic, oscillatory eye movement with at least 1 slow phase. Jerk nystagmus has a slow phase and a fast phase. Pendular nystagmus has only slow phases. Nystagmus is distinguished from other types of oscillatory eye movements, such as saccadic intrusions or oscillations. Characterizing nystagmus requires clearly describing its trajectory. This includes choosing a reference frame to describe the axes or planes and direction of eye movements. Several attributes are used to describe nystagmus: binocularity, conjugacy, velocity, waveform, frequency, amplitude, intensity, temporal profile, and age at first appearance. Several factors may influence nystagmus, including gaze position, visual fixation, vergence, and a variety of provocative maneuvers. Classification of nystagmus may be organized by physiologic or pathologic nystagmus versus other nystagmus-like movements. Pathologic nystagmus may be spontaneous, gaze-evoked, or triggered by provocative maneuvers. The combination of attributes allows differentiation between the many peripheral and central forms. RECOMMENDATIONS FOR CLINICAL PRACTICE Therapists should carefully examine and characterize the trajectory and other attributes and influencing factors of nystagmus to accurately classify it and arrive at the correct diagnosis.
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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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Tarnutzer AA, Straumann D, Salman MS. Neuro-ophthalmologic assessment and investigations in children and adults with cerebellar diseases. THE CEREBELLUM: FROM EMBRYOLOGY TO DIAGNOSTIC INVESTIGATIONS 2018; 154:305-327. [DOI: 10.1016/b978-0-444-63956-1.00019-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Zee DS, Jareonsettasin P, Leigh RJ. Ocular stability and set-point adaptation. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0199. [PMID: 28242733 DOI: 10.1098/rstb.2016.0199] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2016] [Indexed: 11/12/2022] Open
Abstract
A fundamental challenge to the brain is how to prevent intrusive movements when quiet is needed. Unwanted limb movements such as tremor impair fine motor control and unwanted eye drifts such as nystagmus impair vision. A stable platform is also necessary to launch accurate movements. Accordingly, nature has designed control systems with agonist (excitation) and antagonist (inhibition) muscle pairs functioning in push-pull, around a steady level of balanced tonic activity, the set-point Sensory information can be organized similarly, as in the vestibulo-ocular reflex, which generates eye movements that compensate for head movements. The semicircular canals, working in coplanar pairs, one in each labyrinth, are reciprocally excited and inhibited as they transduce head rotations. The relative change in activity is relayed to the vestibular nuclei, which operate around a set-point of stable balanced activity. When a pathological imbalance occurs, producing unwanted nystagmus without head movement, an adaptive mechanism restores the proper set-point and eliminates the nystagmus. Here we used 90 min of continuous 7 T magnetic field labyrinthine stimulation (MVS) in normal humans to produce sustained nystagmus simulating vestibular imbalance. We identified multiple time-scale processes towards a new zero set-point showing that MVS is an excellent paradigm to investigate the neurobiology of set-point adaptation.This article is part of the themed issue 'Movement suppression: brain mechanisms for stopping and stillness'.
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Affiliation(s)
- D S Zee
- Department of Neurology, Johns Hopkins Hospital, 600 N. Wolfe St, Baltimore, MD 21287, USA
| | - P Jareonsettasin
- Oxford University Hospitals, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
| | - R J Leigh
- Department of Neurology, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106-5040, USA
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Abstract
PURPOSE OF REVIEW This article summarizes an approach to evaluating dizziness for the general neurologist and reviews common and important causes of dizziness and vertigo. RECENT FINDINGS Improved methods of diagnosing patients with vertigo and dizziness have been evolving, including additional diagnostic criteria and characterization of some common conditions that cause dizziness (eg, vestibular migraine, benign paroxysmal positional vertigo, chronic subjective dizziness). Other uncommon causes of dizziness (eg, superior canal dehiscence syndrome, episodic ataxia type 2) have also been better clarified. Distinguishing between central and peripheral causes of vertigo can be accomplished reliably through history and examination, but imaging techniques have further added to accuracy. What has not changed is the necessity of obtaining a basic history of the patient's symptoms to narrow the list of possible causes. SUMMARY Dizziness and vertigo are extremely common symptoms that also affect function at home and at work. Improvements in the diagnosis and management of the syndromes that cause dizziness and vertigo will enhance patient care and cost efficiencies in a health care system with limited resources. Clinicians who evaluate patients with dizziness will serve their patient population well by continuing to manage patients with well-focused workup and attentive care.
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Kim SH, Zee DS, du Lac S, Kim HJ, Kim JS. Nucleus prepositus hypoglossi lesions produce a unique ocular motor syndrome. Neurology 2016; 87:2026-2033. [PMID: 27733568 DOI: 10.1212/wnl.0000000000003316] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/27/2016] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To describe the ocular motor abnormalities in 9 patients with a lesion involving the nucleus prepositus hypoglossi (NPH), a key constituent of a vestibular-cerebellar-brainstem neural network that ensures that the eyes are held steady in all positions of gaze. METHODS We recorded eye movements, including the vestibulo-ocular reflex during head impulses, in patients with vertigo and a lesion involving the NPH. RESULTS Our patients showed an ipsilesional-beating spontaneous nystagmus, horizontal gaze-evoked nystagmus more intense on looking toward the ipsilesional side, impaired pursuit more to the ipsilesional side, central patterns of head-shaking nystagmus, contralateral eye deviation, and decreased vestibulo-ocular reflex gain during contralesionally directed head impulses. CONCLUSIONS We attribute these findings to an imbalance in the NPH-inferior olive-flocculus-vestibular nucleus loop, and the ocular motor abnormalities provide a new brainstem localization for patients with acute vertigo.
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Affiliation(s)
- Sung-Hee Kim
- From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea
| | - David S Zee
- From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea
| | - Sascha du Lac
- From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea
| | - Hyo Jung Kim
- From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea
| | - Ji-Soo Kim
- From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea.
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Avoiding “HINTS Positive/Negative” to Minimize Diagnostic Confusion in Acute Vertigo and Dizziness. JOURNAL OF ACUTE CARE PHYSICAL THERAPY 2016. [DOI: 10.1097/jat.0000000000000042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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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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Physical Therapy Diagnostic Process in a Hospital Inpatient With Lateral Canal Benign Paroxysmal Positional Vertigo and Vestibular Hypofunction. JOURNAL OF ACUTE CARE PHYSICAL THERAPY 2016. [DOI: 10.1097/jat.0000000000000019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Jung I, Kim JS. Approach to dizziness in the emergency department. Clin Exp Emerg Med 2015; 2:75-88. [PMID: 27752577 PMCID: PMC5052860 DOI: 10.15441/ceem.15.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 04/21/2014] [Accepted: 04/21/2014] [Indexed: 02/07/2023] Open
Abstract
Acute dizziness/vertigo is among the most common causes for visiting the emergency department. The traditional approach to dizziness starts with categorizing dizziness into four types: vertigo, presyncope, disequilibrium, and nonspecific dizziness. However, a recently proposed approach begins with classifying dizziness/vertigo as acute prolonged spontaneous dizziness/vertigo, recurrent spontaneous dizziness/vertigo, recurrent positional vertigo, or chronic persistent dizziness and imbalance. Vestibular neuritis and stroke are key disorders causing acute prolonged spontaneous dizziness/vertigo, but the diagnosis of isolated vascular vertigo has increased by virtue of developments in clinical neurotology and neuroimaging. However, a well-organized bedside examination appears more sensitive than brain imaging in diagnosing strokes presenting with acute dizziness/vertigo. A detailed history is vital to diagnose recurrent spontaneous dizziness/vertigo since confirmatory diagnostic tests are usually unavailable. Isolated positional vertigo is usually caused by benign paroxysmal positional vertigo, which can be treated at the bedside. In recent years, marked progress has occurred in the evaluation/management of acute dizziness/vertigo. However, even with developments in imaging technology, the diagnosis of acute dizziness/vertigo largely relies on bedside examination.
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Affiliation(s)
- Ileok Jung
- Department of Neurology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Ji-Soo Kim
- Department of Neurology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
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Toosy A, Ciccarelli O, Thompson A. Symptomatic treatment and management of multiple sclerosis. HANDBOOK OF CLINICAL NEUROLOGY 2014; 122:513-562. [PMID: 24507534 DOI: 10.1016/b978-0-444-52001-2.00023-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The range of symptoms which occur in multiple sclerosis (MS) can have disabling functional consequences for patients and lead to significant reductions in their quality of life. MS symptoms can also interact with each other, making their management challenging. Clinical trials aimed at identifying symptomatic therapies have generally been poorly designed and have tended to be underpowered. Therefore, the evidence base for the management of MS symptoms with pharmacologic therapies is not strong and tends to rely upon open-label studies, case reports, and clinical trials with small numbers of patients and poorly validated clinical outcome measures. Recently, there has been a growing interest in the management of MS symptoms with pharmacologic treatments, and better-designed, randomized, double-blind, controlled trials have been reported. This chapter will describe the evidence base predominantly behind the various pharmacologic approaches to the management of MS symptoms, which in most, if not all, cases, requires multidisciplinary input. Drugs routinely recommended for individual symptoms and new therapies, which are currently in the development pipeline, will be reviewed. More interventional therapies related to symptoms that are refractory to pharmacotherapy will also be discussed, where relevant.
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Affiliation(s)
- Ahmed Toosy
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London, UK
| | - Olga Ciccarelli
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London, UK
| | - Alan Thompson
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London, UK.
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Huh YE, Kim JS. Bedside evaluation of dizzy patients. J Clin Neurol 2013; 9:203-13. [PMID: 24285961 PMCID: PMC3840130 DOI: 10.3988/jcn.2013.9.4.203] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 07/31/2013] [Accepted: 07/31/2013] [Indexed: 02/02/2023] Open
Abstract
In recent decades there has been marked progress in the imaging and laboratory evaluation of dizzy patients. However, detailed history taking and comprehensive bedside neurotological evaluation remain crucial for a diagnosis of dizziness. Bedside neurotological evaluation should include examinations for ocular alignment, spontaneous and gaze-evoked nystagmus, the vestibulo-ocular reflex, saccades, smooth pursuit, and balance. In patients with acute spontaneous vertigo, negative head impulse test, direction-changing nystagmus, and skew deviation mostly indicate central vestibular disorders. In contrast, patients with unilateral peripheral deafferentation invariably have a positive head impulse test and mixed horizontal-torsional nystagmus beating away from the lesion side. Since suppression by visual fixation is the rule in peripheral nystagmus and is frequent even in central nystagmus, removal of visual fixation using Frenzel glasses is required for the proper evaluation of central as well as peripheral nystagmus. Head-shaking, cranial vibration, hyperventilation, pressure to the external auditory canal, and loud sounds may disclose underlying vestibular dysfunction by inducing nystagmus or modulating the spontaneous nystagmus. In patients with positional vertigo, the diagnosis can be made by determining patterns of the nystagmus induced during various positional maneuvers that include straight head hanging, the Dix-Hallpike maneuver, supine head roll, and head turning and bending while sitting. Abnormal smooth pursuit and saccades, and severe imbalance also indicate central pathologies. Physicians should be familiar with bedside neurotological examinations and be aware of the clinical implications of the findings when evaluating dizzy patients.
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Affiliation(s)
- Young-Eun Huh
- Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
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Khojasteh E, Bockisch CJ, Straumann D, Hegemann SCA. A mechanism for eye position effects on spontaneous nystagmus. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:3572-5. [PMID: 23366699 DOI: 10.1109/embc.2012.6346738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In acute stages of unilateral vestibular deficit, the imbalanced tonic activity on vestibular afferents evokes spontaneous nystagmus. The slow-phase velocity of this nystagmus varies with eye position, such that it is smaller when looking in the direction of slow-phases. The neural mechanism for this behavior is still not understood. Here, using a simple control system model, we show that plausible changes in the neural responses within the central vestibulo-ocular reflex pathway are adequate to cause eye position dependent effects in the nystagmus pattern. The proposed transformations in population response functions could happen immediately following a lesion and can be useful to stabilize gaze in part of the gaze field.
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Affiliation(s)
- Elham Khojasteh
- Department of Otorhinolaryngology, Head and Neck Surgery, Vestibulo-Oculomotor Laboratory, University Hospital Zürich, Zürich, Switzerland .
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Abstract
Aminopyridines are members of a family of monoamino and diamino derivatives of pyridine, and their principal mechanism of action is dose-dependent blockade of voltage-gated potassium channels, in particular, fast voltage-gated potassium channels. To date, only 2 main broad-spectrum potassium channel blockers, 4-aminopyridine (4-AP) and 3,4-diaminopyridine (3,4-DAP), have been used as investigational new drugs in various neurological diseases. More recently, licensed versions of these compounds including dalfampridine extended release (Fampyra, Biogen Idec) for the improvement of walking in adult patients with multiple sclerosis, and amifampridine (Firdapse, Biomarin Europe Ltd) for the treatment of Lambert-Eaton myasthenic syndrome have been released, and the costs associated with using these new products highlights the importance of evaluating the clinically meaningful treatment effects of these drugs.The current review summarizes the evidence of aminopyridine use in neurological conditions and in particular presents a systematic review of all randomized trials of 3,4-DAP in Lambert-Eaton myasthenic syndrome to determine the efficacy of this treatment using meta-analysis of clinical and electrophysiological end points.
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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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Pettorossi VE, Panichi R, Botti FM, Kyriakareli A, Ferraresi A, Faralli M, Schieppati M, Bronstein AM. Prolonged asymmetric vestibular stimulation induces opposite, long-term effects on self-motion perception and ocular responses. J Physiol 2013; 591:1907-20. [PMID: 23318876 DOI: 10.1113/jphysiol.2012.241182] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Self-motion perception and the vestibulo-ocular reflex (VOR) were investigated in healthy subjects during asymmetric whole body yaw plane oscillations while standing on a platform in the dark. Platform oscillation consisted of two half-sinusoidal cycles of the same amplitude (40°) but different duration, featuring a fast (FHC) and a slow half-cycle (SHC). Rotation consisted of four or 20 consecutive cycles to probe adaptation further with the longer duration protocol. Self-motion perception was estimated by subjects tracking with a pointer the remembered position of an earth-fixed visual target. VOR was measured by electro-oculography. The asymmetric stimulation pattern consistently induced a progressive increase of asymmetry in motion perception, whereby the gain of the tracking response gradually increased during FHCs and decreased during SHCs. The effect was observed already during the first few cycles and further increased during 20 cycles, leading to a totally distorted location of the initial straight-ahead. In contrast, after some initial interindividual variability, the gain of the slow phase VOR became symmetric, decreasing for FHCs and increasing for SHCs. These oppositely directed adaptive effects in motion perception and VOR persisted for nearly an hour. Control conditions using prolonged but symmetrical stimuli produced no adaptive effects on either motion perception or VOR. These findings show that prolonged asymmetric activation of the vestibular system leads to opposite patterns of adaptation of self-motion perception and VOR. The results provide strong evidence that semicircular canal inputs are processed centrally by independent mechanisms for perception of body motion and eye movement control. These divergent adaptation mechanisms enhance awareness of movement toward the faster body rotation, while improving the eye stabilizing properties of the VOR.
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Affiliation(s)
- V E Pettorossi
- Department of Medicina Interna, Sezione di Fisiologia Umana, Universit`a di Perugia, Perugia, Italy
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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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Khojasteh E, Bockisch CJ, Straumann D, Hegemann SCA. A dynamic model for eye-position-dependence of spontaneous nystagmus in acute unilateral vestibular deficit (Alexander's Law). Eur J Neurosci 2012; 37:141-9. [DOI: 10.1111/ejn.12030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 09/11/2012] [Accepted: 09/19/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Elham Khojasteh
- Department of Otorhinolaryngology; University Hospital Zurich; CH-8091; Zurich; Switzerland
| | | | - Dominik Straumann
- Department of Neurology; University Hospital Zurich; Zurich; Switzerland
| | - Stefan C. A. Hegemann
- Department of Otorhinolaryngology; University Hospital Zurich; CH-8091; Zurich; Switzerland
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Anastasopoulos D, Anagnostou E. Invariance of vestibulo-ocular reflex gain to head impulses in pitch at different initial eye-in-orbit elevations: implications for Alexander's law. Acta Otolaryngol 2012; 132:1066-72. [PMID: 22668130 DOI: 10.3109/00016489.2012.682120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSIONS These findings are in line with previous data on the horizontal vestibulo-ocular reflex (VOR) from this laboratory and suggest that eye position signals do not modulate natural vestibular responses. Hence, the Alexander's law (AL) phenomenon cannot be interpreted simply as a consequence of vestibular or oculomotor nuclei activity modulation with desired gaze. BACKGROUND AL states that the intensity of the spontaneous nystagmus of a patient with a unilateral vestibular lesion grows with increasing gaze in the direction of the fast phase. Some of the mechanisms proposed to account for the gaze effects assume a direct modification of the normal VOR by eye position signals. We tested the validity of these assumptions and investigated the effects of gaze direction on the normal vertical human VOR in the behaviorally relevant high frequency range. METHODS Head and eye movements were recorded with the search coil method during passive head impulses in pitch, while subjects were asked to hold gaze at various elevation angles in 8° steps within ± 16° from the straight ahead reference position. RESULTS Upward and downward head rotations produced VOR gains of similar magnitude. Furthermore, the gain remained unaffected by eye-in-orbit position for both upward and downward head impulses.
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Affiliation(s)
- Dimitri Anastasopoulos
- Dizziness and Balance Unit, Department of Physiology, School of Nursing, University of Athens, Greece.
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Abstract
We review current concepts of nystagmus and saccadic oscillations, applying a pathophysiological approach. We begin by discussing how nystagmus may arise when the mechanisms that normally hold gaze steady are impaired. We then describe the clinical and laboratory evaluation of patients with ocular oscillations. Next, we systematically review the features of nystagmus arising from peripheral and central vestibular disorders, nystagmus due to an abnormal gaze-holding mechanism (neural integrator), and nystagmus occurring when vision is compromised. We then discuss forms of nystagmus for which the pathogenesis is not well understood, including acquired pendular nystagmus and congenital forms of nystagmus. We then summarize the spectrum of saccadic disorders that disrupt steady gaze, from intrusions to flutter and opsoclonus. Finally, we review current treatment options for nystagmus and saccadic oscillations, including drugs, surgery, and optical methods. Examples of each type of nystagmus are provided in the form of figures.
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Affiliation(s)
- Matthew J Thurtell
- Departments of Neurology and Daroff-Dell'Osso Laboratory, Veterans Affairs Medical Center and University Hospitals, Case Western Reserve University, Cleveland, OH 44106, USA
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Manzari L, Burgess AM, MacDougall HG, Curthoys IS. Enhanced otolithic function in semicircular canal dehiscence. Acta Otolaryngol 2011; 131:107-12. [PMID: 20863151 DOI: 10.3109/00016489.2010.507780] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The enhanced sound- and vibration-induced vestibular evoked myogenic potentials (VEMPs) and their lower threshold in patients with a thinning of the bony wall of the superior semicircular canal (superior canal dehiscence, SCD) have been interpreted as being due to the dehiscence allowing sound and vibration to activate, unusually, the receptors of the dehiscent semicircular canal. We report a patient with bilateral SCD, as verified by high resolution CT scans, who had bilaterally decreased superior semicircular canal function, as shown by rotational tests of canal function. This patient also showed enhanced VEMPs and reduced thresholds. We conclude that in this patient the enhanced VEMP responses are thus probably due to enhanced otolithic stimulation by sound and vibration after dehiscence.
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Rubenzer SJ, Stevenson SB. Horizontal gaze nystagmus: a review of vision science and application issues. J Forensic Sci 2010; 55:394-409. [PMID: 20102467 DOI: 10.1111/j.1556-4029.2009.01289.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The Horizontal Gaze Nystagmus (HGN) test is one component of the Standardized Field Sobriety Test battery. This article reviews the literature on smooth pursuit eye movement and gaze nystagmus with a focus on normative responses, the influence of alcohol on these behaviors, and stimulus conditions similar to those used in the HGN sobriety test. Factors such as age, stimulus and background conditions, medical conditions, prescription medications, and psychiatric disorder were found to affect the smooth pursuit phase of HGN. Much less literature is available for gaze nystagmus, but onset of nystagmus may occur in some sober subjects at 45 degrees or less. We conclude that HGN is limited by large variability in the underlying normative behavior, from methods and testing environments that are often poorly controlled, and from a lack of rigorous validation in laboratory settings.
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Harris CM, Jacobs M, Shawkat F, Taylor D. Human ocular motor neural integrator failure. Neuroophthalmology 2009. [DOI: 10.3109/01658109309036999] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Waespe W, Martin P. Pursuit eye movements in a patient with a lesion involving the vestibular nuclear complex. Neuroophthalmology 2009. [DOI: 10.3109/01658108709007452] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Simonsz HJ, Kommerell G. Effect Of Prolonged Monocular Occlusion On Latent Nystagmus. Neuroophthalmology 2009. [DOI: 10.3109/01658109209058136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Quarck G, Lhuisset L, Etard O, Denise P. Eye eccentricity modifies the perception of whole-body rotation. Exp Brain Res 2009; 196:295-301. [PMID: 19479247 DOI: 10.1007/s00221-009-1828-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Accepted: 04/23/2009] [Indexed: 11/29/2022]
Abstract
In order to explore the effect of gaze orientation on whole-body rotation perception, ten healthy participants were rotated in the dark while fixating on a visual target located either straight ahead or 15 degrees to the right. A vestibular-memory contingent saccade paradigm was used to estimate the rotation perception. The results attest to the participants' ability to accurately perceive their rotation, based solely on the intrinsic inputs (somesthetic and mainly vestibular), since the correlation between the imposed body rotation and the saccade amplitude was significant and positive. However, the rotation perception was less accurate and of lesser magnitude when the gaze was deviated in the opposite direction to the rotation than when it was either straight ahead or deviated in the direction of the rotation. This can be interpreted as the perceptual equivalent of Alexander's law.
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Bockisch CJ, Hegemann S. Alexander's law and the oculomotor neural integrator: three-dimensional eye velocity in patients with an acute vestibular asymmetry. J Neurophysiol 2008; 100:3105-16. [PMID: 18799600 DOI: 10.1152/jn.90381.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
According to Alexander's law (AL), the slow phase velocity of nystagmus of vestibular origin is dependent on horizontal position, with lower velocity when gaze is directed in the slow compared with the fast phase direction. Adaptive changes in the velocity-to-position neural integrator are thought to cause AL. Although these changes have been described for the horizontal neural integrator, nystagmus often includes vertical and torsional components, but the adaptive abilities of the vertical and torsional integrators have not been investigated. We measured 11 patients with a peripheral vestibular asymmetry and used second-order equations to describe how velocity varied with position. Horizontal velocity changed with horizontal position in accordance with AL and the second-order term for horizontal position was also significant. Whereas velocity decreased in the slow phase direction, it was relatively unchanged >10 degrees into the fast phase direction. Vertical velocity was also highest in the vertical fast phase direction and the second-order term for vertical position was also significant, in that vertical velocity increased in the vertical fast phase direction, but was unchanging in the slow phase direction. Torsional velocity varied linearly with horizontal, but not vertical, position. These results show that the horizontal and vertical oculomotor neural integrators react to altered vestibular input by maintaining different integrating time constants depending on gaze direction.
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Affiliation(s)
- Christopher J Bockisch
- Department of Otorhinolaryngology, Head and Neck Surgery, Zürich University Hospital, Zurich, Switzerland.
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