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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Five patients with optic ataxia together with tactile apraxia are described. They also demonstrated difficulty in finger movements under visual guidance. The CT scan showed lesions in the posterior parietal region in three and in two they were located anteriorly. It is well recognised that lesions in the posterior parietal area may cause disruption of visual guided movements. On the basis of the two cases it is postulated that the same phenomenon could occur with lesions located more anteriorly. The assumption is that optic ataxia may occur either following damage to the parieto-occipital region or to disruption of its occipitofrontal connections.
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PMID:Optic ataxia following unilateral stroke. 956 68

Early alexia and higher visual impairments characterize Posterior cortical atrophy (PCA), a progressive dementing syndrome most often caused by Alzheimer disease. Posterior cortical atrophy is rare, and the nature of the visual impairments in PCA are unclear. The authors observed two patients who had an insidiously progressive reading difficulty characterized by letter-by-letter reading and otherwise intact cognitive functions. Over time, these patients developed "ventral simultanagnosia" with preserved detection of multiple stimuli but inability to interpret whole scenes. Subsequently, they progressed to Balint syndrome with "dorsal simultanagnosia," optic ataxia, and oculomotor apraxia. Structural imaging was normal, but functional imaging revealed posterior cortical dysfunction. On a letter reading task, both patients had a word superiority effect, and on a whole word reading task, they could not read most words with missing or crosshatched letters. An inability to assess whole scenes progressed to an inability to detect more than one stimulus in an array. These findings suggest an evolution of PCA with progressive difficulty in visual integration beginning with letters, progressing to whole scenes, and culminating in Balint syndrome. These changes may reflect an extension of the pathophysiology of PCA from the extrastriate visual cortex to its occipitotemporal and occipitoparietal connections.
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PMID:The evolution of alexia and simultanagnosia in posterior cortical atrophy. 965 88

We report a 73-year-old woman who presented progressive motor clumsiness, cortical sensory loss, and focal parietal lobe atrophy. She was well until one year prior to the present admission when she suffered from what appeared to be mild Fisher syndrome from which she showed excellent recovery. However, soon she noted a gradual onset of difficulty in hand movements and in the recognition of objects by hands. Neurologic examination revealed an alert and well oriented Japanese woman without dementia. Cranial nerves were unremarkable. Although, she did not have aphasia, apraxia, or agnosia, she showed marked clumsiness in skilled hand movements such as using chopsticks, hand writing, and buttoning. She had no motor weakness, ataxia, rigidity, or spasticity. Deep tendon reflexes were symmetrically diminished. Sensory examination revealed cortical sensory loss such as disturbances of two point discrimination, weight sensation, and stereotactic sensations. Her motor clumsiness appeared to be caused by her cortical sensory loss. MRI revealed marked focal atrophy in the bilateral parietal lobe, particularly in the postcentral gyrus and the adjacent association areas. Recently, neurodegenerative disorders with focal brain atrophy such as corticobasal degeneration, Pick's disease, and dementia of frontal lobe type have been reported, however, our patient does not fit to any of these known disorders nor clinical features are distinctly different from Alzheimer's disease. Our patient may be another example of progressive cerebral degeneration with emphasis on the parietal cortex.
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PMID:[A patient with focal bi-parietal atrophy presenting motor clumsiness and cortical sensory loss]. 971 Nov 23

We prospectively studied motor symptoms in 32 patients with CT- or MRI-proven acute pure parietal stroke. A transient, mild, 'pseudoparesis' of the hand (90%), was noted, improved by visual attention and prompting, associated with non-awareness of muscle power (53%), transient soft pyramidal signs (50%), unilateral akinesia (100%) and motor hemineglect (37%) in non-dominant lesions. Lower motoneurone-type atrophy was not observed in this acute phase. We called 'poikilotonia' the striking unpredictable variations in muscle tone, ranging from extreme hypertonia to hypotonia, found in all patients. When maintaining postures, patients showed large oscillations (100%), laterodeviation or levitation of the arm (60%), especially in the case of large or posterior lesions, or, occasionally (3%), motor persistence or even hemicatalepsy (3%). Limb kinetic and manipulatory apraxia, with inadequate organization and anticipation of motor sequences and synergies, motor arrests, perplexity, unrecognizable gestures and loss of bimanual coordination, was a constant finding (100%). Other apraxias (62%) and difficulty in copying intransitive gestures of the hand (84%) were associated with posterior lesions involving the supramarginal gyrus. When reaching towards objects, all patients showed abnormal anticipatory hand shaping, but visuomotor ataxia (3%) was only seen with bilateral posterior stroke. Sensory (70%) or pseudocerebellar (4%) ataxia, was seen in both anterior and posterior lesions. Avoidance behaviors (34%) were not uncommon, but had no localizing value. Of the dyskinesias, hand dystonia (84%) was frequent, but athetosis (16%), asterixis (15%), postural tremor (15%), myoclonus (9%) and stereotypia (9%), were uncommon. The abnormal eye movements were unilateral hypo-akinesia of exploratory saccades (43%), abnormal ipsilateral pursuit and contralateral optokinetic nystagmus in the case of posterior lesions, and oculomotor apraxia with bilateral posterior lesions. In conclusion, parietal motor syndrome can be recognized during bedside examination, and probably reflects the loss of multiple sensory feedback to motor programs, especially those directed to the extrapersonal space.
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PMID:Parietal motor syndrome: a clinical description in 32 patients in the acute phase of pure parietal strokes studied prospectively. 987 53

To investigate complaints of Gulf War veterans, epidemiologic, case-control and animal modeling studies were performed. Looking for OPIDP variants, our epidemiologic project studied 249 Naval Reserve construction battalion (CB24) men. Extensive surveys were drawn for symptoms and exposures. An existing test (PAI) was used for neuropsychologic. Using FACTOR, LOGISTIC and FREQ in 6.07 SAS, symptom clusters were sought with high eigenvalues from orthogonally rotated two-stage factor analysis. After factor loadings and Kaiser measure for sampling adequacy (0.82), three major and three minor symptom clusters were identified. Internally consistent by Cronbach's coefficient, these were labeled syndromes: (1) impaired cognition; (2) confusion-ataxia; (3) arthro-myo-neuropathy; (4) phobia-apraxia; (5) fever-adenopathy; and (6) weakness-incontinence. Syndrome variants identified 63 patients (63/249, 25%) with 91 syndromes. With pyridostigmine bromide as the drug in these drug-chemical exposures, syndrome chemicals were: (1) pesticide-containing flea and tick collars (P < 0.001); (2) alarms from chemical weapons attacks (P < 0.001), being in a sector later found to have nerve agent exposure (P < 0.04); and (3) insect repellent (DEET) (P < 0.001). From CB24, 23 cases, 10 deployed and 10 non-deployed controls were studied. Auditory evoked potentials showed dysfunction (P < 0.02), nystagmic velocity on rotation testing, asymmetry on saccadic velocity (P < 0.04), somatosensory evoked potentials both sides (right P < 0.03, left P < 0.005) and synstagmic velocity after caloric stimulation bilaterally (P-range, 0.02-0.04). Brain dysfunction was shown on the Halstead Impairment Index (P < 0.01), General Neuropsychological Deficit Scale (P < 0.03) and Trail Making part B (P < 0.03). Butylcholinesterase phenotypes did not trend for inherent abnormalities. Parallel hen studies at Duke University established similar drug-chemical delayed neurotoxicity. These investigations lend credibility that sublethal exposures to drug-chemical combinations caused delayed-onset neurotoxic variants.
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PMID:Epidemiological association in US veterans between Gulf War illness and exposures to anticholinesterases. 1002 6

A 66-year-old right-handed man with acquired stuttering was reported. He complained of paresis in his left leg and speech dysfluency. He was not aphasic in terms of comprehension and writing. His speech dysfluency was mainly characterized by initial syllable repetitions. He has apraxia with his left hand, but has neither agraphia with his left hand nor crossed optic ataxia. MRI showed cerebral infarction in the truncus of the corpus callosum, and angiography revealed occlusion of the right anterior cerebral artery. 99mTc HM-PAO SPECT showed decreased blood flow in the right frontal lobe. Within six months of its onset, the patient's speech dysfluency had diminished. As the causative lesion for acquired stuttering, we proposed a hemispheric lesion in addition to a callosal lesion.
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PMID:[Acquired stuttering associated with callosal infarction: a case report]. 1002 89

Scrapie is a degenerative disease of the central nervous system of sheep and goats. The causative agent has been passaged to a number of laboratory species, including mice and hamster. Amyloid plaque formation and vacuolation, the signs of senile dementia, are found in the brains of mice infected with 87V scrapie agent. Dopamine (DA) and norepinephrine (NE) concentrations in the brains of scrapie-infected mice were measured with high-performance liquid chromatography-electrochemical detector (HPLC-ECD). A significant decrease in NE level was exhibited in all regions tested, whereas the level of DA decreased significantly only in cerebral cortex. Immunohistochemistry was used to examine immunoreactive catecholamine neurons in substantia nigra and locus ceruleus using antisera against tyrosine hydroxylase (TH). The population of TH-immunoreactive neurons in the substantia nigra and locus ceruleus were significantly decreased in scrapie-infected mice compared to controls. These data suggest that both the noradrenergic and dopaminergic system are sensitive to the action of scrapie agent 87V and that changes in the catecholamine levels in the brains of scrapie-infected mice may contribute to some of the clinical symptoms of the diseases, such as ataxia and apraxia.
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PMID:Extensive degeneration of catecholaminergic neurons to scrapie agent 87V in the brains of IM mice. 1032 12

Multiple sclerosis (MS) is associated with postural instability and an increased risk of falling which is facilitated by a variety of factors including diminished visual acuity, diplopia, ataxia, apraxia of gait, and peripheral neuropathy. Deficient binocular depth perception may also contribute to a higher incidence of postural instability and falling in these patients who, for example, find it an extremely difficult task to walk on uneven ground, over curbs, or up and down steps. I report a 51 year old woman with secondary progressive MS who experienced difficulties with binocular depth perception resulting in frequent falls and injuries. Deficient depth perception was demonstrated also on spontaneous drawing of a cube. Following a series of transcranial treatments with AC pulsed electromagnetic fields (EMFs) of 7,5 picotesla flux density, the patient experienced a major improvement in depth perception which was evident particularly on ascending and descending stairs. These clinical changes were associated with an improvement in spatial organization and depth perception on drawing a cube. These findings suggest that in MS impairment of depth perception, which is encoded in the primary visual cortex (area 17) and visual association cortex (areas 18 and 19), may be improved by administration of AC pulsed EMFs of picotesla flux density. The primary visual cortex is densely innervated by serotonergic neurons which modulate visual information processing. Cerebral serotonin concentrations are diminished in MS patients and at least some aspects of deficient depth perception in MS may be related to dysfunction of serotonergic transmission in the primary visual cortex. It is suggested that transcranial AC pulsed applications of EMFs improve depth perception partly by augmenting serotonergic transmission in the visual cortex.
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PMID:Impairment of depth perception in multiple sclerosis is improved by treatment with AC pulsed electromagnetic fields. 1039 63

We describe two new clinical syndromes, mirror agnosia and mirror ataxia, both characterized by the deficit of reaching for an object through a mirror in association with a lesion of either parietal lobe. Clinical investigation of 13 patients demonstrated that the impairments affected both sides of the body. In mirror agnosia, the patients always reached toward the virtual object in the mirror and they were not capable of changing their behavior even after presentation of the position of the object in real visual space. In mirror ataxia (resembling optic ataxia) although some patients initially tended to reach for the virtual object in the mirror, they soon learned to guide their arms toward the real object, all of them producing many directional errors. Both patient groups performed poorly on mental rotation, but only the patients with mirror agnosia were impaired in line orientation. Only 1 of the patients suffered from neglect and 3 from apraxia. Magnetic resonance imaging showed that in mirror agnosia the common zone of lesion overlap was scattered around the posterior angular gyrus/superior temporal gyrus and in mirror ataxia around the postcentral sulcus. We propose that both these clinical syndromes may represent different types of dissociation of retinotopic space and body scheme, or likewise, of allocentric and egocentric space normally adjusted in the parietal lobe.
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PMID:Mirror agnosia and mirror ataxia constitute different parietal lobe disorders. 1076 76

The clinical presentation of children with Joubert syndrome can include nonspecific features such as hypotonia, ataxia, and developmental delay. Careful examination of the face shows a characteristic appearance, and a neuro-ophthalmologic examination shows the presence of oculomotor apraxia. In the neonatal period, most children have hyperpnea intermixed with central apnea. Neuroimaging of the head in the axial plane demonstrates the "molar tooth sign"--deep posterior interpeduncular fossa, thick and elongated superior cerebellar peduncles, and hypoplastic or aplastic superior cerebellar vermis. The central nervous system malformation spectrum observed in radiologic and neuropathologic studies accounts for many clinical features of Joubert syndrome. The developmental delay and cognitive impairment cannot be fully explained by the hindbrain malformation and probably result from dysfunction of the cerebral hemispheres. Although related conditions with vermian hypoplasia or aplasia (including Arima; Senior-Loken; and cerebellar vermian hypoplasia, oligophrenia, congenital ataxia, coloboma, and hepatic fibrosis syndromes) can mimic Joubert syndrome, detailed imaging data are lacking in such cases. We propose a revision in diagnostic criteria for Joubert syndrome.
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PMID:Clinical features and revised diagnostic criteria in Joubert syndrome. 1048 3


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