O3-035 Downbeat nystagmus in acute cerebellitis: Altered feed-forward inhibition by the cerebellum to the vertical vestibulo-ocular reflex

Downbeat nystagmus occurs as a result of an impaired vestibulo-ocular reflex1. From animal experiments, the Purkinje cells of the flocculonodular and parafloccular lobes of the cerebellum (also known as the “vestibular cerebellum”) are known to negatively regulate the upward rotation of the eyes via feed-forward inhibitory neural circuitry to the vertical vestibulo-ocular reflex [Supplemental figure 1,links.lww.com/CPJ/A199) 2. Although various eye movement abnormalities have been described in congenital and acquired cerebellar disorders, there have been few reports of pure downbeat nystagmus in cerebellitis.Here we report a quite impressive pure downbeat nystagmus in an adolescent female with acute cerebellitis. The electro-oculography of the patient provided compelling evidence that the downbeat nystagmus is indeed the result of feed-forward inhibition to the vestibulo-ocular reflex. Our case may add new insights into the current literature on cerebellar control of eye movement.

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A – C.A.N.V.A.S (CEREBELLAR ATAXIA, NEURONOPATHY AND VESTIBULAR AREFLEXIA WITH AUTONOMIC DYSFUNCTION): A FASCINATING CLINICAL PORTRAIT

East European Journal of Parkinson`s Disease and Movement Disorders ◽

10.33444/2414-0007.4.3-4.3-8 ◽

2018 ◽

Vol 4 (3-4) ◽

pp. 3-8

Author(s):

Carlo Canepa-Raggio

Keyword(s):

Cerebellar Ataxia ◽

Autonomic Dysfunction ◽

Cerebellar Atrophy ◽

Sensory Neuropathy ◽

Nerve Biopsy ◽

Sural Nerve Biopsy ◽

Downbeat Nystagmus ◽

Charcot Marie Tooth Disease ◽

Ocular Reflex ◽

Vestibulo Ocular Reflex

57-year-old male patient with a 30-year history chronic cough, balance difficulties (most noticeable in the dark), ataxia and sensory neuropathy. There was also evidence of orthostatic hypotension and hypohydrosis. Examination revealed downbeat nystagmus, an abnormal visually-enhanced vestibulo-ocular reflex, length-dependent sensory neuropathy, high-stepping tandem ataxia and bilateral dysmetria. MRI brain shows marked vermian cerebellar atrophy (more noticeable in lobes VI and VIIa/b) and nerve conduction studies reveal absent sensory conductions (ganglionopathy). Genetic testing for Friedrich’s ataxia, spinocerebellar ataxia and hereditary motor sensory neuropathy (Charcot-Marie-Tooth disease) were all negative. Sural nerve biopsy showed pattern of severe loss of myelinated fibres. This patient was diagnosed with cerebellar ataxia, neuronopathy (ganglionopathy) and vestibular areflexia with autonomic dysfunction. Keywords: ataxia, neuronopathy, vestibular areflexia, autonomic dysfunction.

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Ictal downbeat nystagmus in Ménière disease

Neurology ◽

10.1212/wnl.0000000000010653 ◽

2020 ◽

Vol 95 (17) ◽

pp. e2409-e2417

Author(s):

Sun-Uk Lee ◽

Hyo-Jung Kim ◽

Jeong-Yoon Choi ◽

Ji-Soo Kim

Keyword(s):

Semicircular Canals ◽

Vestibular Evoked Myogenic Potentials ◽

Slow Phase ◽

Downbeat Nystagmus ◽

Meniere Disease ◽

Head Impulse ◽

Slow Phase Velocity ◽

Ocular Reflex ◽

Vestibulo Ocular Reflex ◽

Menière Disease

ObjectiveTo determine the mechanism of ictal downbeat nystagmus in Ménière disease (MD), we compared the head impulse gain of the vestibulo-ocular reflex (VOR) for each semicircular canal between patients with (n = 7) and without (n = 70) downbeat nystagmus during attacks of MD.MethodsWe retrospectively analyzed the results of video-oculography, video head-impulse tests, and cervical vestibular-evoked myogenic potentials (VEMPs) in 77 patients with definite MD who were evaluated during an attack.ResultsPure or predominant downbeat nystagmus was observed in 7 patients (9%) with unilateral MD during the attacks. All 7 patients showed spontaneous downbeat nystagmus without visual fixation with a slow phase velocity ranging from 1.5 to 11.2°/s (median 5.4, interquartile range 3.7–8.5). All showed a transient decrease of the head impulse VOR gains for the posterior canals (PCs) in both ears (n = 4) or in the affected ear (n = 3). Cervical VEMPs were decreased in the affected (n = 2) or both ears (n = 2) when evaluated during the attacks. Downbeat nystagmus disappeared along with normalization of the VOR gains for PCs after the attacks in all patients. During the attacks, the head impulse VOR gains for the PC on the affected side were lower in the patients with ictal downbeat nystagmus than in those without (Mann-Whitney U test, p < 0.001), while the gains for other semicircular canals did not differ between the groups.ConclusionDownbeat nystagmus may be observed during attacks of MD due to an asymmetry in the vertical VOR or saccular dysfunction. MD should be considered in recurrent audiovestibulopathy and ictal downbeat nystagmus.

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Histochemical Characterization of the Vestibular Y-Group in Monkey

The Cerebellum ◽

10.1007/s12311-020-01200-z ◽

2020 ◽

Author(s):

Christina Zeeh ◽

Ümit S. Mayadali ◽

Anja K.E. Horn

Keyword(s):

Projection Neurons ◽

Downbeat Nystagmus ◽

Ocular Reflex ◽

Neuron Populations ◽

Premotor Neurons ◽

Cell Groups ◽

Vestibulo Ocular Reflex ◽

Group Form ◽

Histochemical Characterization

Abstract The Y-group plays an important role in the generation of upward smooth pursuit eye movements and contributes to the adaptive properties of the vertical vestibulo-ocular reflex. Malfunction of this circuitry may cause eye movement disorders, such as downbeat nystagmus. To characterize the neuron populations in the Y-group, we performed immunostainings for cellular proteins related to firing characteristics and transmitters (calretinin, GABA-related proteins and ion channels) in brainstem sections of macaque monkeys that had received tracer injections into the oculomotor nucleus. Two histochemically different populations of premotor neurons were identified: The calretinin-positive population represents the excitatory projection to contralateral upgaze motoneurons, whereas the GABAergic population represents the inhibitory projection to ipsilateral downgaze motoneurons. Both populations receive a strong supply by GABAergic nerve endings most likely originating from floccular Purkinje cells. All premotor neurons express nonphosphorylated neurofilaments and are ensheathed by strong perineuronal nets. In addition, they contain the voltage-gated potassium channels Kv1.1 and Kv3.1b which suggests biophysical similarities to high-activity premotor neurons of vestibular and oculomotor systems. The premotor neurons of Y-group form a homogenous population with histochemical characteristics compatible with fast-firing projection neurons that can also undergo plasticity and contribute to motor learning as found for the adaptation of the vestibulo-ocular reflex in response to visual-vestibular mismatch stimulation. The histochemical characterization of premotor neurons in the Y-group allows the identification of the homologue cell groups in human, including their transmitter inputs and will serve as basis for correlated anatomical-neuropathological studies of clinical cases with downbeat nystagmus.

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Perceived Vertical and Lateropulsion: Clinical Syndromes, Localization, and Prognosis

Neurorehabilitation and Neural Repair ◽

10.1177/154596830001400101 ◽

2000 ◽

Vol 14 (1) ◽

pp. 1-12 ◽

Cited By ~ 25

Author(s):

Thomas Brandt ◽

Marianne Dieterich

Keyword(s):

Downbeat Nystagmus ◽

Topographic Analysis ◽

Ocular Reflex ◽

Clinical Syndromes ◽

Vestibulo Ocular Reflex ◽

Visual Vertical ◽

Central Compensation ◽

Torsional Nystagmus ◽

Straight Ahead

We present a clinical classification of central vestibular syndromes according to the three major planes of action of the vestibulo-ocular reflex: yaw, roll, and pitch. The plane-specific syndromes are determined by ocular motor, postural, and percep tual signs. Yaw plane signs are horizontal nystagmus, past pointing, rotational and lat eral body falls, deviation of perceived straight-ahead to the left or right. Roll plane signs are torsional nystagmus, skew deviation, ocular torsion, tilts of head, body, and perceived vertical in a clockwise or counterclockwise direction. Pitch plane signs are upbeat/downbeat nystagmus, forward/backward tilts and falls, deviations of the per ceived horizon. The thus defined vestibular syndromes allow a precise topographic analysis of brainstem lesions according to their level and side. Special emphasis is placed on the vestibular roll plane syndromes of ocular tilt reaction, lateropulsion in Wallenberg's syndrome, thalamic and cortical astasia and their association with roll plane tilt of perceived vertical. Recovery is based on a functionally significant central compensation of a vestibular tone imbalance, the mechanism of which is largely un known. Physical therapy may facilitate this central compensation, but this has not yet been proven in prospective studies. Key Words: Visual vertical—Lateropulsion— Vestibulo-ocular reflex—Central vestibular syndromes.

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Cerebellar Dizziness and Vertigo: Etiologies, Diagnostic Assessment, and Treatment

Seminars in Neurology ◽

10.1055/s-0039-3400315 ◽

2019 ◽

Vol 40 (01) ◽

pp. 087-096 ◽

Cited By ~ 1

Author(s):

Andreas Zwergal ◽

Katharina Feil ◽

Roman Schniepp ◽

Michael Strupp

Keyword(s):

Balance Training ◽

Vestibular Function ◽

Downbeat Nystagmus ◽

Ocular Reflex ◽

Assessment And Treatment ◽

Gaze Holding ◽

Risk Of Falls ◽

Vestibulo Ocular Reflex ◽

Cerebellar Ataxias ◽

Vertical Nystagmus

AbstractCerebellar dizziness and vertigo account for approximately 10% of diagnoses in a tertiary dizziness center. This term summarizes a large group of disorders with chronic (degenerative, hereditary, acquired cerebellar ataxias), recurrent (episodic ataxias), or acute (stroke, inflammation) presentations. Key to the diagnosis is a comprehensive examination of central ocular motor and vestibular function. Patients with cerebellar dizziness and vertigo usually show a pattern of deficits in smooth pursuit, gaze-holding, saccade accuracy, or fixation-suppression of the vestibulo-ocular reflex. Central fixation nystagmus (e.g., downbeat nystagmus), gaze-evoked nystagmus, central positional nystagmus, or head-shaking nystagmus with cross-coupling (i.e., horizontal head shaking causing inappropriate vertical nystagmus) occurs frequently. Overlap syndromes with peripheral vestibular disorders, such as cerebellar ataxia, neuropathy, and vestibular areflexia, exist rarely. Posturography and gait analysis can contribute to diagnostic differentiation, estimation of the risk of falls, as well as quantification of progression and treatment effects. Patients with cerebellar dizziness and vertigo should receive multimodal treatment, including balance training, occupational therapy, and medication.

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