Bovine viral diarrhea-mucosal disease implicated in a calf with cerebellar hypoplasia and ocular disease. A case report.
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Case history of a 20-year old man with Hodgkin's disease, clinical stage I, lymphocytic predominance, complicated by a subacute cerebellar degeneration, which was diagnosed by computed tomography scan. Following local radiotherapy, cerebellar and brain stem symptoms and signs had a complete regression. Two months later, a recurrence of the neurological picture was recorded: polychemotherapy (MOPP) was then administered and after 5 courses the symptoms improved considerably. The association of subacute cerebellar degeneration with Hodgkin's disease is rare: only 10 cases have previously been described. Pathogenesis of cerebellar atrophy complicating tumors is undetermined.
Ataxia with ocular motor apraxia type 1 (AOA1) is an autosomal recessive cerebellar ataxia (ARCA) associated with oculomotor apraxia, hypoalbuminaemia and hypercholesterolaemia. The gene APTX, which encodes aprataxin, has been identified recently. We studied a large series of 158 families with non-Friedreich progressive ARCA. We identified 14 patients (nine families) with five different missense or truncating mutations in the aprataxin gene (W279X, A198V, D267G, W279R, IVS5+1), four of which were new. We determined the relative frequency of AOA1 which is 5%. Mutation carriers underwent detailed neurological, neuropsychological, electrophysiological, oculographic and biological examinations, as well as brain imaging. The mean age at onset was 6.8 +/- 4.8 years (range 2-18 years). Cerebellar ataxia with cerebellar atrophy on MRI and severe axonal sensorimotor neuropathy were present in all patients. In contrast, oculomotor apraxia (86%), hypoalbuminaemia (83%) and hypercholesterolaemia (75%) were variable. Choreic movements were frequent at onset (79%), but disappeared in the course of the disease in most cases. However, a remarkably severe and persistent choreic phenotype was associated with one of the mutations (A198V). Cognitive impairment was always present. Ocular saccade initiation was normal, but their duration was increased by the succession of multiple hypometric saccades that could clinically be confused with 'slow saccades'. We emphasize the phenotypic variability over the course of the disease. Cerebellar ataxia and/or chorea predominate at onset, but later on they are often partially masked by severe neuropathy, which is the most typical symptom in young adults. The presence of chorea, sensorimotor neuropathy, oculomotor anomalies, biological abnormalities, cerebellar atrophy on MRI and absence of the Babinski sign can help to distinguish AOA1 from Friedreich's ataxia on a clinical basis. The frequency of chorea at onset suggests that this diagnosis should also be considered in children with chorea who do not carry the IT15 mutation responsible for Huntington's disease.
A 5-year-old Staffordshire terrier exhibited slowly progressive signs of cerebellar disease, including nystagmus and dysmetria. After a 30-month course, the dog was euthanized. Grossly, the cerebellum was small and comprised only 5% of the brain weight. Histopathological examination of the brain documented diffuse degeneration. Purkinje cells were most depleted, but granular cells and the molecular layer of cerebellum were also depleted. The history and necropsy examination were evidence of late-onset primary cerebellar degeneration.
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Abstract. Although its metabolic basis has not yet been clarified, we report a progressive white-matter disease in a Turkish girl, starting in the cerebellum and spreading to supratentorial white matter. The onset was at the age of 2.5 years with diabetes insipidus, followed by ataxia and pyramidal signs resulting in loss of walking. Aqueduct stenosis was first recognised at the age of 8 years. To our knowledge, this MRI and clinical pattern does not correspond to a recognised, well-defined white-matter disease and may indicate a separate entity.
BACKGROUND AND PURPOSE: Posterior reversible encephalopathy syndrome (PRES) is typically characterized by headache, altered mental functioning, seizures, and visual loss associated with imaging findings of bilateral subcortical and cortical edema with a predominantly posterior distribution. Our goal was to determine whether fluid-attenuated inversion recovery (FLAIR) imaging improves the ability to detect subtle peripheral lesions of PRES, as compared with conventional MR techniques. METHODS: Sixteen patients with clinical and imaging findings consistent with PRES were studied. Thirteen patients had undergone transplantation and had cyclosporin A neurotoxicity. Fast-FLAIR images were compared with spin-echo proton density- and T2-weighted images. RESULTS: FLAIR imaging improved diagnostic confidence and conspicuity of the T2 hyperintense lesions of PRES, typically in the subcortical white matter of the parietooccipital regions bilaterally. On all 23 abnormal MR studies, FLAIR was judged superior to proton density- and T2-weighted images for the detection of PRES in the supratentorial brain. In a mean of 6.7 of 23 studies, FLAIR findings prompted a raise in the grade of disease severity. FLAIR also showed cortical involvement in 94% of patients with PRES and in a mean of 46% of the total lesion burden. In four cases, subtle lesions were virtually undetectable without FLAIR. Brain stem or cerebellar disease was encountered in 56% of patients. CONCLUSION: FLAIR improves the ability to diagnose and detect subcortical and cortical lesions in PRES as compared with proton density- and T2-weighted spin-echo images. We therefore believe that FLAIR should be performed in patients with suspected PRES to allow more confident recognition of the often subtle imaging abnormalities.
Although isolated lower motor neuron disease has been reported as a paraneoplastic complication, it has not been previously described, in association with anti-Hu antibody. We report a 51-year-old man in whom weakness heralded the presence of a small-cell cancer of the lung. His neurological disorder was characterized by an unremitting progression of limb, neck, and chest wall weakness and wasting that commenced and remained predominant in the upper limbs. Electrophysiological studies demonstrated widespread denervation and examination of a muscle biopsy specimen showed evidence of acute and chronic denervation. High titers of anti-Hu antibody were detected in the serum and cerebrospinal fluid. Neither objective measures of strength nor titers of anti-Hu antibody responded to corticosteroids, cyclophosphamide, intravenous immunoglobulins, or plasmapheresis. Death from the complications of motor neuron disease ensued 23 months after the onset of weakness. Autopsy revealed tumor in the lung and on pleural and peritoneal surfaces. There was a loss of anterior horn cells in the spinal cord. Despite the absence of symptomatic cerebellar disease, a decrease in the number of Purkinje cells was also detected.
Hand muscle reflexes to stretch or electric stimulation of mixed nerves consist of two main components, the short latency reflex (SLR, M1) or Hoffmann reflex (HR) and the long latency reflex (LLR, M2). The SLR is most likely a spinal, monosynaptic reflex and all the evidence presently available supports a transcortical pathway of the LLR. Investigations in normal subjects demonstrate that the LLR is a reflex mediated by fast conducting muscle and cutaneous afferents. Group II muscle afferents do not significantly contribute to this reflex and it cannot be explained by repetitive excitation of spinal oligosynaptic pathways. These findings should not be uncritically generalized to other muscle groups, because the central and peripheral mechanisms apparently differ according to the body region and mode of stimulation. The LLR of hand muscles is most likely involved in skillful movements of the fingers. It is believed to assist rapid compensatory responses to unexpected disturbances. In addition to the main component of the LLR, which is called LLR II, the study of electrically elicited thenar reflexes following stimulation of the median nerve disclosed further LLR components, the LLR I and the LLR III. The latter reflexes are rarely seen in normal subjects but have a significance in several diseases. Several abnormalities could be demonstrated in different diseases. Enhanced HR and reduced LLR are found in spasticity of various origin. Enhanced LLR I are frequently seen in Parkinson's disease, essential tremor and reflex myoclonus. Absent or reduced LLR II is found in Huntington's disease and in different focal brain lesions but not in symptomatic choreatic syndromes of other origin. Delayed latencies of the LLR II or absent LLR II have been described in multiple sclerosis. Enhanced LLR III may occur in cerebellar diseases. The method to elicit LLR of thenar muscles by electric stimulation may prove to be useful for clinical neurophysiology.
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A neural network model of opponent cerebellar learning for arm movement control is proposed. The model illustrates how a central pattern generator in cortex and basal ganglia, a neuromuscular force controller in spinal cord, and an adaptive cerebellum cooperate to reduce motor variability during multijoint arm movements using mono- and bi-articular muscles. Cerebellar learning modifies velocity commands to produce phasic antagonist bursts at interpositus nucleus cells whose feed-forward action overcomes inherent limitations of spinal feedback control of tracking. Excitation of alpha motoneuron pools, combined with inhibition of their Renshaw cells by the cerebellum, facilitate movement initiation and optimal execution. Transcerebellar pathways are opened by learning through long-term depression (LTD) of parallel fiber-Purkinje cell synapses in response to conjunctive stimulation of parallel fibers and climbing fiber discharges that signal muscle stretch errors. The cerebellar circuitry also learns to control opponent muscles pairs, allowing cocontraction and reciprocal inhibition of muscles. Learning is stable, exhibits load compensation properties, and generalizes better across movement speeds if motoneuron pools obey the size principle. The intermittency of climbing fiber discharges maintains stable learning. Long-term potentiation (LTP) in response to uncorrelated parallel fiber signals enables previously weakened synapses to recover. Loss of climbing fibers, in the presence of LTP, can erode normal opponent signal processing. Simulated lesions of the cerebellar network reproduce symptoms of cerebellar disease, including sluggish movement onsets, poor execution of multijoint plans, and abnormally prolonged endpoint oscillations.
By contrast to cerebellar hypermetria, the pathophysiology of cerebellar hypometria associated with a focal lesion is poorly understood. We describe a patient presenting an ischemic stroke involving the left lateral pons and middle cerebellar peduncle and exhibiting severely hypometric ballistic movements of the left wrist. Hypometria was associated with two distinct abnormalities of the triphasic electromyographic (EMG) pattern: a prolongation of the duration of the antagonist EMG activity and a reduced intensity of the agonist EMG activity. The first mechanism has been described previously in patients with a cerebellar disease and exhibiting hypometria, but not the second. The concomitant presence of these two elementary mechanisms contributed to the severity of hypometria in our patient. Moreover, this case illustrates that the integrity of the crossed pontocerebellar fibers passing through the middle cerebellar peduncle is necessary to generate an adequate agonist EMG activity.
Patients with different vestibular disorders exhibit changes in postural behaviour when they receive visual stimuli, reproducing environmental stimulation. Postural control was studied using an AMTI Accusway platform, measuring the confidential ellipse (CE) and sway velocity (SV). Postural responses were recorded according to the following stimulation paradigm: i) without specific stimuli; ii) smooth pursuit with pure sinusoids of 0.2 Hz (foveal stimulation); and iii) optokinetic stimulation (retinal stimuli). Patients with central vestibular disorders (CVD), cerebellar damage and unilateral peripheral vestibular lesions (UPVL) in asymptomatic periods were studied. A group of normal subjects was studied as control. Signal processing was done with a scalogram by wavelets in order to observe the relation between time and frequency in postural control. While patients with CVD and cerebellar disease showed a significant increase in CE and SV in the three conditions of the paradigm compared to the normal group, the patients with UPVL showed no change. Wavelets processing showed that the main sway occurs in the Y axis (antero-posterior) and below at 0.4 Hz in normal subjects, while the CVD and cerebellar patients showed sway frequencies in both the X and Y axes. The clinical implications of these findings are discussed.
Previous studies of our group have shown that cerebellar patients are impaired in their ability to associate a color and a numeral or two colors with a button push. The aim of the present study was to examine whether control subjects make use of sequence information in visuomotor associative learning tasks and if this ability is impaired in cerebellar patients. A group of eight patients with degenerative cerebellar disease and eight age, sex and IQ matched controls were tested. Subjects had to learn the association between pairs of colored squares and a button push. Two colored squares were shown one after the other in a fixed or random order on a computer screen. Control subjects but not cerebellar patients took advantage of the fixed order information of colored squares in order to improve associative learning. Differences between groups could not be explained by differences in verbal and visuospatial short-term memory, color discrimination, affective state or motor disturbances. Results suggest that impaired sequencing of sensory stimuli may contribute to disorders in visuomotor associative learning in cerebellar patients.
With the intention to assess remote effects of cerebellar dysfunction, 23 patients with inherited or idiopathic cerebellar ataxia were studied with positron emission tomography (PET) and 2[18F]fluoro-2-deoxy-D-glucose (FDG). Eight patients (group 1) suffered from early onset cerebellar ataxia (EOCA, age of symptom onset <20 years), nine patients (group 2) from late onset cerebellar ataxia (LOCA, symptom onset between the ages of 20 and 50), and six patients (group 3) experienced symptom onset beyond the age of 50 years. The pattern of cerebral glucose metabolism in cerebellar ataxia was compared to the results in a control group of 16 healthy subjects. In all patients, a reduction in relative (EOCA, group 1) or absolute (LOCA, groups 2 and 3) values of regional cerebral glucose metabolism (rCMR(glu)) occurred in both cerebellar hemispheres as well as the vermis and both dentate nuclei. In patients from all groups presenting with a clinical syndrome of pure cerebellar ataxia, impairment of regional glucose metabolism also extended to the pontine and brainstem regions. In contrast to this infratentorial reduction of rCMR(glu) in all patients, in those with LOCA, a significant relative increase in rCMR(glu) was present in distinct supratentorial cortical regions, namely the cuneus, the pre-cuneus and the gyrus supramarginalis in the patients of group 2. In group 3, this significant relative increase in rCMR(glu) was restricted to the cuneus. Thus, FDG-PET in patients suffering from cerebellar ataxia shows distinct patterns of altered glucose metabolism which exceed pure cerebellar impairment. Most importantly, FDG-PET yields insight into the influence of cerebellar disease on supratentorial glucose metabolism and documents impairment of supratentorial neuronal function with relative sparing of the parietal cortex.
Neurodegenerative diseases are characterised by selective damage to specific neurons in the nervous system. Interest in such diseases in humans has resulted in considerable progress in the molecular understanding of these disorders in recent decades. Numerous neurodegenerative diseases have also been described in domestic animals but relatively little molecular work has been reported. In the present review, we have classified neurodegenerative disease according to neuroanatomical criteria. We have established two large groups, based on whether the neuronal cell body or its axon was primarily affected. Conditions such as motor neuron diseases, cerebellar degenerations and neuroaxonal dystrophies are discussed in terms of their clinical and neuropathological features. In the most studied disorders, we also present what is known about underlying pathomechanisms, and compare them with their human counterparts. The purpose of this review is to re-kindle interest in this group of diseases and to encourage veterinary researchers to investigate molecular mechanisms by taking advantage of current diagnostic tools.