What causes hemiataxia after lacunar ischaemic stroke? A cliniconeurophysiological study

Both cerebellar dysfunction and proprioceptive deficits have been described as the cause of the ataxia in patients with ataxic hemiparesis. In order to determine the cause of the ataxia, we investigated the sensory modalities and performed median nerve somatosensory evoked potentials (SEPs) in 19 patients with hemiataxia following lacunar ischaemic stroke. All patients had computer tomography (CT) and/or magnetic resonance imaging (MRI) of the brain. SEP results were reviewed for correlation with clinical features and infarct location and size. In all patients, eye closure did not worsen the ataxia. There was no difference between the mean latency of the SEP components from the affected and non-affected hemisphere of the brain in all patients. Only two of the 19 patients had abnormal SEPs. There was no correlation between SEP findings, clinical features and location or size of the infarcts. The discovery of normal SEPs in most cases and the clinical aspects of the ataxia suggest that hemiataxia following lacunar ischaemic stroke is usually of the cerebellar type and that disturbed proprioception is unlikely as the cause in most patients. Cerebellar-like ataxia is most likely caused by disruption of the cerebellar pathways at the level of the internal capsule or corona radiata, i.e. either the ascending dentatorubrothalamocortical or the descending corticopontocerebellar pathways.     

Ataxia teleangiectatica; elektronenmikroskopische Biopsiebefunde des Nervus suralis von 2 Fällen

Zusammenfassung Nach zahlreichen klinischen, elektromyographischen, bioptisch-lichtmikroskopischen und autoptischen Erfahrungen ist auch das periphere Nervensystem häufig am Krankheitsprozeß der Ataxia teleangiectatica (AT) beteiligt. Elektronenmikroskopisch zeigen Suralisbiopsien eines Brüderpaares mit AT eine Speicherung diverser Lipidartikel in Schwannschen Zellen bemarkter und unbemarkter Nervenzellen sowie leichte axonale Degenerationen. Diese Befunde bestätigen weitgehend die Ergebnisse, die Gardner u. Goodman (1969) bei der bisher einzigen derartigen Biopsie beschrieben. Gestützt auf die dargestellten morphologischen Beobachtungen wird eine enzymatische Störung des Lipidmetabolismus oder eine lysosomale Fermentanomalie als pathogenetischer Faktor der AT diskutiert.

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Ataxia teleangiectasia; electron microscopic study of two nerve biopsies

Summary Neumerous clinical, electromyographic and morphological findings are indicating that the peripheral nerve is often involved in ataxia teleangiectasia (AT). Electron micrographs of sural nerves of two brothers with AT reveal various lipid-containing particles within Schwann cells of myelinated fibers and, in addition, a slight axonal degeneration. These results confirm the findings of Gardner and Goodman (1969) in the only biopsy to be reported to date. The morphological alterations demonstrated raise the question whether an enzymatic error of lipid metabolism or a lysosomal enzyme anomaly represent a pathogenetic factor in AT.

     

The effect of varying periods of administration and the cessation of administration of sodium diethyldithiocarbamate upon the central nervous system of domestic fowl

Summary Nerve fibre degeneration occurred in the white matter of the spinal cord of cocks following the daily oral administration of sodium diethyldithiocarbamate (NaDDC) for 4 weeks or more. Lesions were also found in birds that had received the compound for 3 weeks and were killed 3 weeks after cessation of administration. Following the cessation of administration of NaDDC to ataxic birds their coordination improved. After a time the number of degenerating fibres in the spinal cord decreased and fibrous gliosis occurred in the ventral but not in the lateral columns.     

Familial ataxia of the rabbit Sawin-Anders type

Summary This hereditary animal ataxia is selective in its sites of involvement within the nervous system, which include principally the central cerebellar, vestibular and cochlear nuclei. Ultrastructural detail has been described for central cerebellar and vestibular nuclei. Herein the cochlear complex of 18 rabbits with this ataxic condition (ax/ax from the strain AX of the Jackson Laboratory) have been examined. The gene is a lethal one, but the animals were used before they became moribund and between 7 and 57 days after the onset of symptoms.By light microscopy nine cell types (Osen, 1969a, b; 1970) have been identified in the cochlear nuclei of the cat. That distribution can also be identified in electron micrographs of rabbit cochlear nuclei, providing there is a singular opportunity to compare cellular vulnerabilities within the ataxic condition, and establish the principal features of associated neuropil alterations. The cochlear nuclei, cerebellar cortex and central nuclei, and the vestibular nuclei, arise from the ependyma of the rhombic lip of the fourth ventricle, making them close allies in their genetic origins.Pathological alterations were evident in scattered neurons from all nuclear sources by 7–15 days following symptom onset. At 15 days the number of altered neurons evident in electronmicrographs had increased markedly, cells becoming involved at a more rapid pace than those already affected could be removed. Much glycogen is evident from 7 days onwards in both neuropil and neurons. It occurs in considerable amounts in astrocytic processes and less abundantly in endbulbs and somata. By 20 to 25 days spongioform changes in neuropil are prominent, and thereafter the extracellular spaces coalesce to produce a lacunar appearance showing little glycogen. It would appear, therefore, that all neuron types, the endbulbs, and the astrocytic processes are markedly involved simultaneously in the spongioform transformation which features this type of ataxia. Involvement of cochlear nuclei only differs in pathological detail from that found at the other involved sites, and the differences seen relate principally to the architectonics of the nuclei, including size and density of the packing of contained elements.Aided by USPHS Program Project Grant NS-04513, NIH Research Grants RR-00251, from the Division of Research Resources, HO-01496, from the National Institute of Child Health and Human Development, and allocations from General Research Support Grant RR-05545 from the Division of Research Resources to the Jackson Laboratory.     

Truncal ataxia in chronic anticonvulsant treatment. Association with drug-induced folate deficiency

The association of truncal ataxia with a number of different factors has been studied in a group of 95 epileptic outpatients on chronic anticonvulsant treatment. The 28 patients showing truncal ataxia had been epileptic for a longer period of time, received a significantly larger number of drugs, and had higher serum levels of phenobarbital than the non-ataxic group. Serum folate levels were significantly lower in the ataxic group. A role is postulated for anticonvulsant-induced folate deficiency in the appearance of truncal ataxia presenting after prolonged anti-convulsant therapy, either by increasing the serum levels of the anticonvulsants or through other, unknown mechanisms. The presence of tonic-clonic seizures, presumably associated with brain anoxia, was not associated with the appearance of truncal ataxia.     

A comparison of the effects of neuroleptics on phencyclidine-induced behaviors in the rat

The dose-response effects of neuroleptic pretreatment on phencyclidine (PCP; 3 or 5 mg/kg)-induced locomotor activity, stereotyped behaviors and ataxia were quantified in groups of male rats using rating scales recently developed in this laboratory. Three butyrophenone neuroleptics consistently produced dose-dependent antagonism of the behavioral effects of PCP administration. Fluphenazine antagonized the behavioral effects produced by 3 mg/kg PCP but not those produced by 5 mg/kg PCP. Each of the other neuroleptics examined (chlorpromazine, thioridazine, mesoridazine, triflupromazine, cis-flupenthixol) had no consistent antagonistic effect or actually enhanced one or more of the behavioral effects of PCP. Some neuroleptics slightly reduced PCP locomotion or stereotypies at high doses, but these effects were probably a non-specific consequence of the synergistic ataxia-producing properties of these drugs. In a second set of experiments, atropine sulfate pretreatment increased PCP-induced locomotor activity and stereotyped behaviors but had no effect on ataxia; pretreatment with physostigmine produced opposite effects. Combined pretreatment with haloperidol and atropine sulfate significantly reduced only haloperidol antagonism of PCP-induced ataxia, thus suggesting that non-dopoaminergic effects of neuroleptics may interfere with their ability to antagonize PCP.     

Cocaine antagonizes anxiolytic effects of ethanol

A Geller-Seifter paradigm for discerning anxiolytic and ataxic effects of drugs was used to study the interactions between low doses of ethanol and cocaine. Ethanol produced significant anxiolytic and ataxic effects at a dose of 1 g/kg. Cocaine at a dose as low as 10 mg/kg markedly antagonized the anxiolytic effect of ethanol, but simultaneously augmented ethanol's ataxic effects, as measured by response rates during a random-interval schedule. These results indicate that ethanol may interact to a significant degree with brain aminergic systems and that, contrary to popular dogma, stimulants may reverse some components of ethanol intoxication, but increase ethanol's debilitating motor effects.     

Gait analysis after intake of increasing amounts of alcohol

Summary The ability to walk after intake of increasing amounts of alcohol was studied. Sixteen normal persons were tested on a computer-assisted treadmill. Ataxia or unsteadiness of gait was found to decrease during a blood alcohol concentration (BAC) of less than 0.4 mg/ml. Stride length was found to increase by increasing BAC.Supported by The Haand-I-Haand-Hafnia Insurance Jubilee Fund, The Jubilee Fund of the Nordic Mutual Insurance Ltd., and the Danish Medical Research Council, grant no. 512-154-15460.     

Cerebellar ataxia. Clinical and CT findings in two cases of rare etiology

Summary Two low density lesions of the cerebellum which did not occupy space are reported. The neuropathological diagnosis of one case was subacute leucencephalitis. In the other case, the diagnosis of a Pelizaeus-Merzbacher's disease is discussed, taking into consideration the clinical observation, development and the CT findings.

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Zusammenfassung Zwei Fälle werden beschrieben, in welchen die Computertomographie eine Läsion von niedriger Dichte im Bereiche des Kleinhirnes ergab. In einem Fall war die neuropathologische Diagnose die einer subakuten Leucencephalitis, im anderen wurde eine Pelizaeus-Merzbacher-Erkrankung vermutet. Letztere wurde unter Berücksichtigung der klinischen Besonderheiten und der Entwicklung der CT-Befunde diskutiert.

     

胚胎小脑悬液移植治疗小脑共济失调的实验研究

应用立体定位仪将兴奋性神经毒素海人藻酸(Kainic acid,KA)直接注入 S-D 大鼠小脑半球后内侧部,造成小脑共济失调的动物模型。用胚胎大鼠小脑制成的细胞悬液移植至模型的大鼠小脑内,用四种功能标准半定量评分观察小脑平衡行为。3个月的观察结果显示:该小脑共济失调模型能较长期保持平衡障碍的体征,而经过移植,平衡障碍得到纠正。3个月后处死动物,发现:KA 模型组γ-氨基丁酸(GABA)升高,胚胎移植后使其下降。门冬氨酸等氨基酸无明显改变。KA 组的 cGMP 下降,移植后回升至对照水平。