Arnold Chiari malformation is a disease which is characterized by herniation of a portion of the cerebellum through the foramen magnum. Symptoms vary depending on the extent of the affected area, including posterior neck pain, upper limb pain, paralysis, paresthesia, weakness, dizziness, and ataxia. Among the patients presenting with dizziness, nystagmus is frequently observed, which is primarily characterized by down-beating nystagmus. We experienced a 42- years-old female patient presented with vertigo and gait disturbance, who were diagnosed with type 1 Arnold-Chiari malformation and treated by surgical decompression.
Spinocerebellar ataxia type 28 (SCA 28) is characterized by young-adult onset, very slowly progressive gait and limb ataxia, dysarthria, nystagmus, ptosis, and ophthalmoplegia. It is caused by a heterozygous pathogenic mutation in the AFG3L2. So far, approximately 80 cases with genetically-confirmed SCA 28 have been reported in the literature. We report a patient with mild gait ataxia and dysarthria who carried a known pathogenic mutation in the AFG3L2. This is the first report of genetically-confirmed SCA 28 in Korea.
Ataxia with ocular motor apraxia type 2 (AOA2) is an autosomal recessive disorder that is characterized by adolescent-onset gait ataxia, peripheral neuropathy, ocular apraxia, and cerebellar atrophy. A 19-year-old male with AOA2 from a novel SETX mutation showed distinct oculomotor abnormalities that included spontaneous and gaze-induced downbeat nystagmus, impaired smooth pursuit, and reversed catch-up saccades during horizontal head impulse tests, as well as peripheral neuropathy involving the lower extremities and mild slowing of frontal processing. He also showed positional hemiseesaw nystagmus in the supine and straight head-hanging positions. Positional hemiseesaw nystagmus is a new manifestation of hereditary cerebellar ataxia and may be explained by a gravity-dependent position-induced error in estimating the tilt in the roll plane due to dysfunction of the tilt-estimator circuit.
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A Case of AOA2 With Compound Heterozygous SETX Mutations Hee Jin Chang, Ryul Kim, Minchae Kim, Jangsup Moon, Man Jin Kim, Han-Joon Kim Journal of Movement Disorders.2022; 15(2): 178. CrossRef
A 84-year-old woman presented with a two weeks history of dizziness, slurred speech and ataxia. The neurological exam showed spontaneous left beating nystagmus, horizontal gaze evoked nystagmus and limb ataxia. A few weeks earlier, she had an upper airway infection. Brain MRI revealed diffuse leptomeningeal enhancement in the both cerebellar hemisphere and brain single photon emission computed tomography (SPECT) showed hyperperfusion in both cerebellar hemisphere. Extensive laboratory studies with cerebrospinal fluid analysis did not reveal any etiologic factors. She was started on methylprednisolone (1 g/day for 7 days), gradually improved over the weeks. Post infectious cerebellar ataxia is a neurologic complication that occasionally follows systemic viral and bacterial infections. This case demonstrates that cerebellar abnormalities can be detected by brain magnetic resonance imaging and SPECT.
Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a slowing progressive ataxic disorder characterized by bilateral vestibulopathy, cerebellar ataxia and somatosensory impairment. Autonomic dysfunction is recently considered as a core feature in CANVAS in addition to these symptoms. In most cases, patients with CANVAS show cerebellar atrophy in brain imaging, but some cases show minimal or no atrophy of cerebellum. Brain (18F)-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) study can be a complimentary tool to diagnosis CANVAS in cases of no structural abnormality such as cerebellar atrophy. Hereby, we present a case of CANVAS with minimal atrophy of cerebellum but showing a prominent hypometabolism in cerebellum, thalamus and posterior cingulate cortex in 18F-FDG PET.
Wernicke’s encephalopathy (WE) is a neurological disorder induced by a dietary vitamin B1 (thiamine) deficiency which is characterized by encephalopathy, gait ataxia, and variant ocular motor dysfunction. In addition to these classical signs of WE, a loss of the horizontal vestibulo-ocular reflex (VOR) is being reported as the major underdiagnosed symptoms in WE. In this retrospective single center study, we report four cases of WE initially presented with impaired horizontal VOR in addition to the classical clinical presentations, and imaging and neurotological laboratory findings were described.
Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements, which may result from abnormalities in different parts of the nervous system including the cerebellum and its connecting pathway, proprioceptive sensory pathway, and vestibular system. In the diagnosis of disorders characterized by cerebellar ataxia, the mode of onset, rate of development, and degree of permanence of the ataxia are of particular importance. In adults, paraneoplastic and demyelinating cases account for the largest proportion of subacute onset, and hereditary forms are the usual cause of very slowly progressive and chronic ones. The last category of genetic ataxias now constitute a large and heterogeneous group for which the basis has been established in most cases. Misalignment of the visual axes-strabismus-causes the two images of a seen object to fall on noncorresponding areas of the two retinas, which usually causes diplopia, the sensation of seeing an object at two different locations in space. Accurate diagnosis of diplopia and strabismus require detailed history on the symptomatology and ocular motor examination consisting of assessment of the range of eye movements, subjective diplopia testing, and cover and alternate cover tests.
Patients with recurrent vertigo/dizziness or unsteadiness are a heterogeneous
group of complex disorders affecting the peripheral and central vestibular system.
They represent a diagnostic challenge for the clinicians, and their genetic basis
is largely not known. However, there are some cerebellar and vestibular disorders
with a strong genetic background, such as episodic ataxia, spinocerebellar ataxia,
vestibular migraine, Meniere’s disease, and autosomal dominant nonsyndromic
deafness. Furthermore, recent advances in next generation sequencing technique
are increasing the number of novel genes associated with cerebellar and vestibular
disorders. In this article, we have summarized clinical and molecular genetics
findings in neuro-otology.
Acute cerebellar ataxia is described as a clinical syndrome of acute onset of
cerebellar dysfunction with a good long-term prognosis. The pathogenesis of acute
cerebellar ataxia remains unclear. A 55-year-old woman presented with acute
onset of gait ataxia and dysarthria. The videonystagmography showed saccadic
pursuit and saccadic abnormalities including slightly prolonged latency and
hypometria. Rotational chair test revealed increased vestibuloocular reflex (VOR)
gains and a failure of VOR suppression by visual fixation. Brain magnetic
resonance imaging and cerebrospinal fluid examination were normal. The patient
was treated with steroids and made nearly complete recovery over a period of
3 months.
Background and Objectives: The vestibulo-ocular reflexes (VOR) act a short latency to optimize vision during locomotion. The angular VOR (aVOR) has been widely studied in human subjects and preserves clear, stable vision during rotational head perturbations by generating eye movements that hold the line of sight on the target of interest. Less is known about the properties of the linear or translational VOR (tVOR), mainly due to technical difficulties posed by testing head or body translations. Geometric considerations indicate that different properties should be expected of tVOR, which can only provide stable vision of objects lying in one depth plane.
Materials and Methods: We studied the human tVOR using a moving platform to translate normal human subjects vertically at frequencies similar to those occurring during locomotion. We found that, whereas aVOR is concerned with holding retinal images fairly stable to optimize clear vision, tVOR seems best suited to minimize relative motion of retinal images belonging to objects lying in different depth planes-and thereby to optimize motion parallax information. We also investigated whether the tVOR functioned abnormally in patients with neurological disorders causing falls-progressive supranuclear palsy (PSP) and cerebellar ataxia.
Results: Both groups of patients showed impaired ability to modulate their tVOR during viewing of near targets; in PSP this might be attributed to failure of convergence, but cerebellar patients failed to modulate tVOR at near despite intact convergence.
Conclusion: In both disorders, an impaired ability to adjust tVOR for viewing distance points to central disturbance of otolithic vestibular reflexes, which may also contribute to postural instability.
Lithium is recognized as a cause of reversible or permanent downbeat nystagmus. Many patients who were treated with lithium for psychiatric illness developed downbeat nystagmus and other neurological manifestations. Reversible splenial lesions of corpus callosum are commonly seen on diffusion-weighted imaging (DWI) in various neurological disorders including metabolic/toxic encephalopathy, encephalitis, patients with epilepsy receiving antiepileptic drugs.
Herein, we report a patient with reversible downbeat nystagmus, disturbance of smooth pursuit, and gait ataxia who was treated with lithium. Also, we can observe reversible splenial lesion of corpus callosum on DWI in this patient.
Optic ataxia is characterized by an impaired visual control of the direction of arm reaching to a visual target, accompanied by defective hand orientation and grip formation. In humans, optic ataxia is associated with lesions of the superior parietal lobule, which also affect visually guided saccades and other forms of eye-hand coordination. A 67-year-old woman presented with sudden, unilateral, direct optic ataxia in the right homonymous half field and saccadic abnormalities which consisted of prolonged latency, undershoot dysmetria, and decreased velocity. Brain MRI showed a left parieto-occipital watershed infarction. It is suggested that lesions of the superior parietal lobule and the adjacent parietal eye field are responsible for optic ataxia and saccadic abnormalities, respectively.
Key Words: Optic ataxia, Saccade, Infarction, Superior parietal lobule