The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform
David S. Zee - One of the best experts on this subject based on the ideXlab platform.
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Vertical Nystagmus in Wernicke’s encephalopathy: pathogenesis and role of central processing of information from the otoliths
Journal of Neurology, 2019Co-Authors: Jorge C. Kattah, Collin Mcclelland, David S. ZeeAbstract:Patients with Wernicke’s encephalopathy (WE) often have unusual patterns of Vertical Nystagmus. Initially there is often a spontaneous upbeating Nystagmus that may change to downbeat Nystagmus with a change in the direction of gaze, convergence or with vestibular stimuli. Patients also often show a profound loss of the horizontal but not the Vertical vestibulo-ocular reflex (VOR). Furthermore, the acute upbeat Nystagmus may change to a chronic downbeat Nystagmus. We present hypotheses for these features based on (1) the location of Vertical gaze-holding networks near the area postrema of the dorsomedial medulla where the blood–brain barrier is located, which we suggest becomes compromised in WE, (2) the location of the vestibular nuclei in the brainstem, medially for the horizontal VOR, and laterally for the Vertical VOR, (3) neuronal circuits differ in susceptibility to and in the ability to recover from thiamine deficiency, and (4) impaired processing of otolith information in WE, normally used to modulate translational vestibulo-ocular reflexes, leads to some of the characteristics of the spontaneous Vertical Nystagmus including the peculiar reversal in its direction with a change in gaze or convergence.
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Vertical Nystagmus in Wernicke's encephalopathy: pathogenesis and role of central processing of information from the otoliths.
Journal of Neurology, 2019Co-Authors: Jorge C. Kattah, Collin M. Mcclelland, David S. ZeeAbstract:Patients with Wernicke's encephalopathy (WE) often have unusual patterns of Vertical Nystagmus. Initially there is often a spontaneous upbeating Nystagmus that may change to downbeat Nystagmus with a change in the direction of gaze, convergence or with vestibular stimuli. Patients also often show a profound loss of the horizontal but not the Vertical vestibulo-ocular reflex (VOR). Furthermore, the acute upbeat Nystagmus may change to a chronic downbeat Nystagmus. We present hypotheses for these features based on (1) the location of Vertical gaze-holding networks near the area postrema of the dorsomedial medulla where the blood-brain barrier is located, which we suggest becomes compromised in WE, (2) the location of the vestibular nuclei in the brainstem, medially for the horizontal VOR, and laterally for the Vertical VOR, (3) neuronal circuits differ in susceptibility to and in the ability to recover from thiamine deficiency, and (4) impaired processing of otolith information in WE, normally used to modulate translational vestibulo-ocular reflexes, leads to some of the characteristics of the spontaneous Vertical Nystagmus including the peculiar reversal in its direction with a change in gaze or convergence.
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spinocerebellar ataxia type 6 gaze evoked and Vertical Nystagmus purkinje cell degeneration and variable age of onset
Annals of Neurology, 1997Co-Authors: Christopher M Gomez, David S. Zee, Randall Thompson, Jason T Gammack, Susan Perlman, William B Dobyns, Charles L Truwit, Brent H Clark, John H AndersonAbstract:Spinocerebellar ataxia type 6 (SCA6) was recently identified as a form of autosomal dominant cerebellar ataxia associated with small expansions of the trinucleotide repeat (CAG)n in the gene CACNL1A4 on chromosome 19p13, which encodes the α1 subunit of a P/Q-type voltage-gated calcium channel. We describe clinical, genetic, neuroimaging, neuropathological, and quantitative oculomotor studies in four kindreds with SCA6. We found strong genetic linkage of the disease to the CACNL1A4 locus and strong association with the expanded (CAG)n alleles in two large ataxia kindreds. The expanded alleles were all of a single size (repeat number) within the two large kindreds, numbering 22 and 23 repeat units. It is noteworthy that the age of onset of ataxia ranged from 24 to 63 years among all affected individuals, despite the uniform repeat number. Radiographically and pathologically, there was selective atrophy of the cerebellum and extensive loss of Purkinje cells in the cerebellar cortex. In addition, clinical and quantitative measurement of extraocular movements demonstrated a characteristic pattern of ocular motor and vestibular abnormalities, including horizontal and Vertical Nystagmus and an abnormal vestibulo-ocular reflex. These studies identify a distinct phenotype associated with this newly recognized form of dominant SCA.
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Spinocerebellar ataxia type 6: Gaze‐evoked and Vertical Nystagmus, Purkinje cell degeneration, and variable age of onset
Annals of neurology, 1997Co-Authors: Christopher M Gomez, David S. Zee, Randall Thompson, Jason T Gammack, Susan Perlman, William B Dobyns, Charles L Truwit, H. Brent Clark, John H AndersonAbstract:Spinocerebellar ataxia type 6 (SCA6) was recently identified as a form of autosomal dominant cerebellar ataxia associated with small expansions of the trinucleotide repeat (CAG)n in the gene CACNL1A4 on chromosome 19p13, which encodes the α1 subunit of a P/Q-type voltage-gated calcium channel. We describe clinical, genetic, neuroimaging, neuropathological, and quantitative oculomotor studies in four kindreds with SCA6. We found strong genetic linkage of the disease to the CACNL1A4 locus and strong association with the expanded (CAG)n alleles in two large ataxia kindreds. The expanded alleles were all of a single size (repeat number) within the two large kindreds, numbering 22 and 23 repeat units. It is noteworthy that the age of onset of ataxia ranged from 24 to 63 years among all affected individuals, despite the uniform repeat number. Radiographically and pathologically, there was selective atrophy of the cerebellum and extensive loss of Purkinje cells in the cerebellar cortex. In addition, clinical and quantitative measurement of extraocular movements demonstrated a characteristic pattern of ocular motor and vestibular abnormalities, including horizontal and Vertical Nystagmus and an abnormal vestibulo-ocular reflex. These studies identify a distinct phenotype associated with this newly recognized form of dominant SCA.
John H Anderson - One of the best experts on this subject based on the ideXlab platform.
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spinocerebellar ataxia type 6 gaze evoked and Vertical Nystagmus purkinje cell degeneration and variable age of onset
Annals of Neurology, 1997Co-Authors: Christopher M Gomez, David S. Zee, Randall Thompson, Jason T Gammack, Susan Perlman, William B Dobyns, Charles L Truwit, Brent H Clark, John H AndersonAbstract:Spinocerebellar ataxia type 6 (SCA6) was recently identified as a form of autosomal dominant cerebellar ataxia associated with small expansions of the trinucleotide repeat (CAG)n in the gene CACNL1A4 on chromosome 19p13, which encodes the α1 subunit of a P/Q-type voltage-gated calcium channel. We describe clinical, genetic, neuroimaging, neuropathological, and quantitative oculomotor studies in four kindreds with SCA6. We found strong genetic linkage of the disease to the CACNL1A4 locus and strong association with the expanded (CAG)n alleles in two large ataxia kindreds. The expanded alleles were all of a single size (repeat number) within the two large kindreds, numbering 22 and 23 repeat units. It is noteworthy that the age of onset of ataxia ranged from 24 to 63 years among all affected individuals, despite the uniform repeat number. Radiographically and pathologically, there was selective atrophy of the cerebellum and extensive loss of Purkinje cells in the cerebellar cortex. In addition, clinical and quantitative measurement of extraocular movements demonstrated a characteristic pattern of ocular motor and vestibular abnormalities, including horizontal and Vertical Nystagmus and an abnormal vestibulo-ocular reflex. These studies identify a distinct phenotype associated with this newly recognized form of dominant SCA.
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Spinocerebellar ataxia type 6: Gaze‐evoked and Vertical Nystagmus, Purkinje cell degeneration, and variable age of onset
Annals of neurology, 1997Co-Authors: Christopher M Gomez, David S. Zee, Randall Thompson, Jason T Gammack, Susan Perlman, William B Dobyns, Charles L Truwit, H. Brent Clark, John H AndersonAbstract:Spinocerebellar ataxia type 6 (SCA6) was recently identified as a form of autosomal dominant cerebellar ataxia associated with small expansions of the trinucleotide repeat (CAG)n in the gene CACNL1A4 on chromosome 19p13, which encodes the α1 subunit of a P/Q-type voltage-gated calcium channel. We describe clinical, genetic, neuroimaging, neuropathological, and quantitative oculomotor studies in four kindreds with SCA6. We found strong genetic linkage of the disease to the CACNL1A4 locus and strong association with the expanded (CAG)n alleles in two large ataxia kindreds. The expanded alleles were all of a single size (repeat number) within the two large kindreds, numbering 22 and 23 repeat units. It is noteworthy that the age of onset of ataxia ranged from 24 to 63 years among all affected individuals, despite the uniform repeat number. Radiographically and pathologically, there was selective atrophy of the cerebellum and extensive loss of Purkinje cells in the cerebellar cortex. In addition, clinical and quantitative measurement of extraocular movements demonstrated a characteristic pattern of ocular motor and vestibular abnormalities, including horizontal and Vertical Nystagmus and an abnormal vestibulo-ocular reflex. These studies identify a distinct phenotype associated with this newly recognized form of dominant SCA.
Dan Milea - One of the best experts on this subject based on the ideXlab platform.
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Vertical Nystagmus: Clinical facts and hypotheses
Brain, 2005Co-Authors: Charles Pierrot-deseilligny, Dan MileaAbstract:The pathophysiology of spontaneous upbeat (UBN) and downbeat (DBN) Nystagmus is reviewed in the light of several instructive clinical findings and experimental data. UBN due to pontine lesions could result from damage to the ventral tegmental tract (VTT), originating in the superior vestibular nucleus (SVN), coursing through the ventral pons and transmitting excitatory upward vestibular signals to the third nerve nucleus. A VTT lesion probably leads to relative hypoactivity of the drive to the motoneurons of the elevator muscles with, consequently, an imbalance between the downward and upward systems, resulting in a downward slow phase. The results observed in internuclear ophthalmoplegia suggest that the medial longitudinal fasciculus (MLF) is involved in the transmission of both upward and downward vestibular signals. Since no clinical cases of DBN due to focal brainstem damage have been reported, it may be assumed that the transmission of downward vestibular signals depends only upon the MLF, whereas that of upward vestibular signals involves both the MLF and the VTT. The main focal lesions resulting in DBN affect the cerebellar flocculus and/or paraflocculus. Apparently, this structure tonically inhibits the SVN and its excitatory efferent tract (i.e. the VTT) but not the downward vestibular system. Therefore, a floccular lesion could result in a disinhibition of the SVN-VTT pathway with, consequently, relative hyperactivity of the drive to the motoneurons of the elevator muscles, resulting in an upward slow phase. UBN also results from lesions affecting the caudal medulla. An area in this region could form part of a feedback loop involved in upward gaze-holding, originating in a collateral branch of the VTT and comprising the caudal medulla, the flocculus and the SVN, successively. Therefore, it is suggested that the main types of spontaneous Vertical Nystagmus due to focal central lesions result from a primary dysfunction of the SVN-VTT pathway, which becomes hypoactive after pontine or caudal medullary lesions, thereby eliciting UBN, and hyperactive after floccular lesions, thereby eliciting DBN. Lastly, since gravity influences UBN and DBN and may facilitate the downward vestibular system and restrain the upward vestibular system, it is hypothesized that the excitatory SVN-VTT pathway, along with its specific floccular inhibition, has developed to counteract the gravity pull. This anatomical hyperdevelopment is apparently associated with a physiological upward velocity bias, since the gain of all upward slow eye movements is greater than that of downward slow eye movements in normal human subjects and in monkeys.
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REVIEW ARTICLE Vertical Nystagmus: clinical facts and hypotheses
2005Co-Authors: Charles Pierrot-deseilligny, Dan MileaAbstract:Summary The pathophysiology of spontaneous upbeat (UBN) and downbeat (DBN) Nystagmus is reviewed in the light of several instructive clinical findings and experimental data. UBN due to pontine lesions could result from damage to the ventral tegmental tract (VTT), originating in the superior vestibular nucleus (SVN), coursing through the ventral pons and transmitting excitatory upward vestibular signals to the third nerve nucleus. A VTT lesion probably leads to relative hypoactivity of the drive to the motoneurons of the elevator muscles with, consequently, an imbalance between the downward and upward systems, resulting in a downward slow phase. The results observed in internuclear ophthalmoplegia suggest that the medial longitudinal fasciculus (MLF) is involved in the transmission of both upward and downward vestibular signals. Since no clinical cases of DBN due to focal brainstem damage have been reported, it may be assumed that the transmission of downward vestibular signals depends only upon the MLF, whereas that of upward vestibular signals involves both the MLF and the VTT. The main focal lesions resulting in DBN affect the cerebellar flocculus and/or paraflocculus. Apparently, this structure tonically inhibits the SVN and its excitatory efferent tract (i.e. the VTT) but not the downward vestibular system. Therefore, a floccular lesion could result in a disinhibition of the SVN‐VTT pathway with, consequently, relative hyperactivity of the drive to the motoneurons of the elevator muscles, resulting in an upward slow phase. UBN also results from lesions affecting the caudal medulla. An area in this region could form part of a feedback loop involved in upward gazeholding, originating in a collateral branch of the VTT and comprising the caudal medulla, the flocculus and the SVN, successively. Therefore, it is suggested that the main types of spontaneous Vertical Nystagmus due to focal central lesions result from a primary dysfunction of the SVN‐VTT pathway, which becomes hypoactive after pontine or caudal medullary lesions, thereby eliciting UBN, and hyperactive after floccular lesions, thereby eliciting DBN. Lastly, since gravity influences UBN and DBN and may facilitate the downward vestibular system and restrain the upward vestibular system, it is hypothesized that the excitatory SVN‐VTT pathway, along with its specific floccular inhibition, has developed to counteract the gravity pull. This anatomical hyperdevelopment is apparently associated with a physiological upward velocity bias, since the gain of all upward slow eye movements is greater than that of downward slow eye movements in normal human subjects and in monkeys.
Christopher M Gomez - One of the best experts on this subject based on the ideXlab platform.
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spinocerebellar ataxia type 6 gaze evoked and Vertical Nystagmus purkinje cell degeneration and variable age of onset
Annals of Neurology, 1997Co-Authors: Christopher M Gomez, David S. Zee, Randall Thompson, Jason T Gammack, Susan Perlman, William B Dobyns, Charles L Truwit, Brent H Clark, John H AndersonAbstract:Spinocerebellar ataxia type 6 (SCA6) was recently identified as a form of autosomal dominant cerebellar ataxia associated with small expansions of the trinucleotide repeat (CAG)n in the gene CACNL1A4 on chromosome 19p13, which encodes the α1 subunit of a P/Q-type voltage-gated calcium channel. We describe clinical, genetic, neuroimaging, neuropathological, and quantitative oculomotor studies in four kindreds with SCA6. We found strong genetic linkage of the disease to the CACNL1A4 locus and strong association with the expanded (CAG)n alleles in two large ataxia kindreds. The expanded alleles were all of a single size (repeat number) within the two large kindreds, numbering 22 and 23 repeat units. It is noteworthy that the age of onset of ataxia ranged from 24 to 63 years among all affected individuals, despite the uniform repeat number. Radiographically and pathologically, there was selective atrophy of the cerebellum and extensive loss of Purkinje cells in the cerebellar cortex. In addition, clinical and quantitative measurement of extraocular movements demonstrated a characteristic pattern of ocular motor and vestibular abnormalities, including horizontal and Vertical Nystagmus and an abnormal vestibulo-ocular reflex. These studies identify a distinct phenotype associated with this newly recognized form of dominant SCA.
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Spinocerebellar ataxia type 6: Gaze‐evoked and Vertical Nystagmus, Purkinje cell degeneration, and variable age of onset
Annals of neurology, 1997Co-Authors: Christopher M Gomez, David S. Zee, Randall Thompson, Jason T Gammack, Susan Perlman, William B Dobyns, Charles L Truwit, H. Brent Clark, John H AndersonAbstract:Spinocerebellar ataxia type 6 (SCA6) was recently identified as a form of autosomal dominant cerebellar ataxia associated with small expansions of the trinucleotide repeat (CAG)n in the gene CACNL1A4 on chromosome 19p13, which encodes the α1 subunit of a P/Q-type voltage-gated calcium channel. We describe clinical, genetic, neuroimaging, neuropathological, and quantitative oculomotor studies in four kindreds with SCA6. We found strong genetic linkage of the disease to the CACNL1A4 locus and strong association with the expanded (CAG)n alleles in two large ataxia kindreds. The expanded alleles were all of a single size (repeat number) within the two large kindreds, numbering 22 and 23 repeat units. It is noteworthy that the age of onset of ataxia ranged from 24 to 63 years among all affected individuals, despite the uniform repeat number. Radiographically and pathologically, there was selective atrophy of the cerebellum and extensive loss of Purkinje cells in the cerebellar cortex. In addition, clinical and quantitative measurement of extraocular movements demonstrated a characteristic pattern of ocular motor and vestibular abnormalities, including horizontal and Vertical Nystagmus and an abnormal vestibulo-ocular reflex. These studies identify a distinct phenotype associated with this newly recognized form of dominant SCA.
Kwang Dong Choi - One of the best experts on this subject based on the ideXlab platform.
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Audiovestibular impairments associated with intracranial hypotension
Journal of the Neurological Sciences, 2015Co-Authors: Jae-hwan Choi, Ji Soo Kim, Kee-yong Cho, Seung-yi Cha, J.-d. Seo, Min-ji Kim, Yu Ri Choi, Sung-hee Kim, Kwang Dong ChoiAbstract:Abstract Objective To investigate the patterns and mechanisms of audiovestibular impairments associated with intracranial hypotension. Methods We had consecutively recruited 16 patients with intracranial hypotension at the Neurology Center of Pusan National University Hospital for two years. Spontaneous, gaze-evoked, and positional Nystagmus were recorded using 3D video-oculography in all patients, and the majority of them also had pure tone audiometry and bithermal caloric tests. Results Of the 16 patients, five (31.3%) reported neuro-otological symptoms along with the orthostatic headache while laboratory evaluation demonstrated audiovestibular impairments in ten (62.5%). Oculographic analyses documented spontaneous and/or positional Nystagmus in six patients (37.5%) including weak spontaneous Vertical Nystagmus with positional modulation (n = 4) and pure positional Nystagmus (n = 2). One patient presented with recurrent spontaneous vertigo and tinnitus mimicking Meniere's disease, and showed unidirectional horizontal and torsional Nystagmus with normal head impulse tests during the attacks. Bithermal caloric tests were normal in all nine patients tested. Audiometry showed unilateral (n = 6) or bilateral (n = 1) sensorineural hearing loss in seven (53.8%) of the 13 patients tested. Conclusions Intracranial hypotension frequently induces audiovestibular impairments. In addition to endolymphatic hydrops and irritation of the vestibulocochlear nerve, compression or traction of the brainstem or cerebellum due to loss of CSF buoyancy may be considered as a mechanism of frequent spontaneous or positional Vertical Nystagmus in patients with intracranial hypotension.
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Patterns of dissociate torsional-Vertical Nystagmus in internuclear ophthalmoplegia.
Annals of the New York Academy of Sciences, 2011Co-Authors: Seong-hae Jeong, Eung Kyu Kim, Jun Lee, Kwang Dong Choi, Ji Soo KimAbstract:To explore the patterns and mechanisms of jerky seesaw Nystagmus in internuclear ophthalmoplegia (INO), we analyzed the Nystagmus patterns in 33 patients with dissociated torsional-Vertical Nystagmus and INO. In 11 (33%) patients, the Nystagmus was ipsiversive torsional in both eyes with Vertical components in the opposite directions. In contrast, 18 (55%) patients showed ipsiversive torsional Nystagmus with a larger upbeat component in the contralesional eye. Four (12%) patients exhibited ipsiversive torsional Nystagmus with a greater downbeat component in the ipsilesional eye. At least one component of contraversive ocular tilt reaction was associated in most patients (30/33, 91%). The patterns of jerky seesaw Nystagmus in INO suggest a disruption of neural pathways from the contralateral Vertical semicircular canals with or without concomitant damage to the fibers from the contralateral utricle in or near the medial longitudinal fasciculus.
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Jerky seesaw Nystagmus in isolated internuclear ophthalmoplegia from focal pontine lesion.
Neurology, 2005Co-Authors: J. H. Chang, Kwang Dong Choi, Kun Woo Park, Dae-hie Lee, Jong S. KimAbstract:Dissociated abducting Nystagmus of the contralesional eye on attempted gaze to the contralesional side is typical of internuclear ophthalmoplegia (INO).1 Rarely, dissociated torsional-Vertical Nystagmus, usually downbeat in the ipsilateral eye and intorsional in the contralateral eye,2,3 or ipsilesional torsional Nystagmus4,5 may occur in INO. We report a patient with isolated INO and jerky seesaw Nystagmus from a focal pontine lesion and discuss possible mechanisms of various torsional-Vertical Nystagmus accompanying INO. A 47-old-woman was admitted with sudden vertigo and oscillopsia. She had diabetes mellitus and previous history of left corona radiata infarction. On admission, she could hardly open the eyes owing to severe oscillopsia. In neutral gaze, she showed extorsional downbeat Nystagmus in the right eye synchronous with intorsional upbeat Nystagmus in the left eye (see the video on the Neurology Web site at www.neurology.org). The Nystagmus was changed into mainly upbeating on upward gaze. On leftward gaze, she also showed adduction paresis of the right eye with dissociated abducting Nystagmus in the left eye (right INO). Convergence was mildly impaired, probably from oscillopsia. Head tilt or skew deviation was not evident. The remainder of the neurologic examination was unrevealing. MRI of the brain disclosed a tiny lesion in the right dorsomedial pontine tegmentum, which corresponds to the known anatomic location of the medial longitudinal fasciculus (MLF) (figure, A through C; see page …
