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Astasia refers to the inability to maintain upright posture during standing, despite having full motor strength. Impairment of the vestibulocerebellar pathway, graviceptive system, and cingulate motor area have been proposed to be related to astasia. However, the responsible neural pathways remain unclear. We hypothesize that there is a common neural network behind astasia. To test the hypothesis, we reviewed all reported cases with astasia, including ours, and focused on the correlation between anatomical destruction and symptom presentation. A total of 26, including ours, non-psychogenic astasia patients were identified in the English literature. Seventy-three percent of them were associated with other neurologic symptoms and sixty-two percent of reported lesions were on the right side. Contralateral lateropulsion was very common, followed by retropulsion, when describing astasia. Infarction (54%) was the most reported cause. The thalamus (65%) was the most reported location. Infarctions were the fastest to recover (mean: 10.6 days), while lesions at the brainstem needed a longer time (mean: 61.6 days). By combining the character of lateropulsion in astasia and the presentation of an interrupted graviceptive system, we concluded that the primary graviceptive system may be the common neural network behind astasia. Future studies on astasia should focus on the pathological changes in the perception of verticality in the visual world and the body. [ABSTRACT FROM AUTHOR]

This article discusses the historical perspective and diagnostic significance of astasia-abasia, a functional movement disorder characterized by the inability to stand and walk. The author highlights the case of Henri Gob, a patient who exhibited an unusual gait disorder and was examined by renowned neurologists. The article also introduces the "swivel chair test," a technique developed to differentiate between functional and organic gait disorders. The author emphasizes the diagnostic complexity of functional disorders and the potential of Henri Gob's case and the swivel chair test to enhance clinicians' understanding of these conditions. [Extracted from the article]

Introduction: Astasia is a rare presenting symptom of stroke, usually known as ‘thalamic astasia', induced by a lesion in the ventrolateral thalamus. We report a case of caudal cingulate infarction manifesting astasia. Case Presentation: A 58-year-old male presented with inability to sit, stand and walk (astasia). No apparent motor weakness was noticed in the extremities. MRI revealed cerebral infarction in the caudal cingulate gyrus, which was located between the vertical commissure anterior (VCA) line and vertical commissure posterior (VPC) line. His symptoms persisted for 1 year to a lesser degree. Conclusion: Lesions in the caudal cingulate gyrus can present with astasia. The responsible lesion is located in the cingulate gyrus between the VCA and VPC line, which might correspond to the caudal cingulate zone in humans. We should keep in mind that astasia can be a presenting symptom of stroke.

Euglena gracilis growth with antibacterial agents leads to bleaching, permanent plastid gene loss. Colorless Euglena ( Astasia) longa resembles a bleached E. gracilis. To evaluate the role of bleaching in E. longa evolution, the effect of streptomycin, a plastid protein synthesis inhibitor, and ofloxacin, a plastid DNA gyrase inhibitor, on E. gracilis and E. longa growth and plastid DNA content were compared. E. gracilis growth was unaffected by streptomycin and ofloxacin. Quantitative PCR analyses revealed a time dependent loss of plastid genes in E. gracilis demonstrating that bleaching agents produce plastid gene deletions without affecting cell growth. Streptomycin and ofloxacin inhibited E. longa growth indicating that it requires plastid genes to survive. This suggests that evolutionary divergence of E. longa from E. gracilis was triggered by the loss of a cytoplasmic metabolic activity also occurring in the plastid. Plastid metabolism has become obligatory for E. longa cell growth. A process termed ' intermittent bleaching', short term exposure to subsaturating concentrations of reversible bleaching agents followed by growth in the absence of a bleaching agent, is proposed as the molecular mechanism for E. longa plastid genome reduction. Various non-photosynthetic lineages could have independently arisen from their photosynthetic ancestors via a similar process. [ABSTRACT FROM AUTHOR]

The various reported psychogenic dyskinesias include tremor, dystonia, myoclonus, gait disorder, Parkinsonism, tics, and chorea. It is not easy to diagnose psychogenic movement disorders, especially in patients with underlying organic disease. We describe three patients with balance and/or posture abnormalities that occur when they stand up, start to move, or halt from walking, although their gaits are normal. One had an underlying unilateral frontal lobe lesion. All patients improved dramatically after receiving a placebo-injection or medication. These abnormal features differ from the previously reported features of astasia without abasia and of psychogenic gait disorders, including recumbent gait. We describe and discuss the patients’ unique clinical characteristics.

This study present 9 species of colourless euglenoid flagellates found in a small peat bog in Budzyń, a village north-west of Cracow, which belongs to the Małopolska Upland (Southern Poland). This threatened peat bog is covered with rubble brought from neighbouring Cracow. Only ca 30% of its area is relatively little influenced by human activity. Many of the present species are rarely and infrequently reported from nature. Three species, including Rhabdomonas incurva Fresenius, Entosiphon obliąuum Klebs, E. ovatum Stokes, and one variety Menoidium pellucidum Perty var. gracile (Playfair) Popova have been recorded for the first time from Poland. Three species Astasia dangeardii Lemmermann var. dangeardii, Rhabdomonas costata (Korsikov) Pringsheim and Entosiphon sulcatum (Dujardin) Stein var. sulcatum Stein are new for the flora of Cracow-Częstochowa Upland. The remaining taxa: Menoidium pellucidum Perty var. pellucidum and M. tortuosum (Stokes) Senn var. tortuosum are very rarely recorded from Poland. For each species illustrations, taxonomic information and biogeographical data are given.

Consumption of alcohol excessively causes dependence and leads to psychological discomfort. Motivation to drink is influenced by a variety of neurobiological and environmental variables. The proclivity of an individual to imbibe is thought to reflect a balance between alcohol’s positive reinforcing (i.e., rewarding) effects, such as euphoria and anxiety reduction (i.e., anxiolysis), and the drug’s aversive effects, which are typically associated with negative consequences of alcohol consumption (e.g., hangover or withdrawal symptoms). Neuroadaptive alterations caused by continuous alcohol use and abuse (such as tolerance and physiological dependence) are regarded to be critical in the shift from regulated alcohol use to more frequent and excessive, uncontrollable drinking which induces cerebellar degeneration considered as common type of acquired toxic ataxia. Excessive use leads to degeneration of the midline cerebellum. Progressive trunk and gait ataxia is characteristic, with little involvement of upper limbs, eyes or speech (a corollary of relative cerebellar hemispheric sparing). Abrupt termination of alcohol use after a period of heavy drinking may result in alcohol withdrawal seizures. Generalized tonic–clonic seizures are the most common and severe form of seizure in this conditions. Current case report presents complaints of astasia and slurred speech with few episodes of seizures. The diagnosis indicated Mild cerebellar atrophy. Patient was advised to undergo de-addiction and cure. [ABSTRACT FROM AUTHOR]

Las Tablas de Daimiel is one of the most important wetlands in the Iberian Península. The increase of water contamination is producing obvious eutrophication. Monthly water samples were taken during 1996 and 1997 at five places - both from channels and shallow water (tablas). 18 taxa of Euglenophyta were found, two of them had been found before in Las Tablas de Daimiel (Astasia sp. and Euglena acus). Nine species are new records for this wetland (E. acilis, E. polymorpha, Lepocinclis ovum var. dimidio-minor. Phacus brevicaudatus, P. pyrum, P. skujae, Trachelomonas armata, T. abrupta and T. volvocinopsis); six species are new records for Spain (E. agilis var. piriformis, E. clara, E. oxyuris var. oxyuris, E. splendens, L. ovum var. globula, and P. brachykentron), and one species is new record for Europe (T. sculpta). The richness of Euglenophyta has increased conspicuously (1 species in 1975, 8 species in 1992-1993 and 18 species in 1996-1997). Moreover, the increasing water level from 19% has reduced the Euglenophyta density and these populations have simultaneously spread throughout the whole Park. The fluctuation seen in the Euglenophyte populations of the Tablas de Daimiel is not a response to contamination events, but the result of a the long eutrophication process endured by these wetlands.

Most of our knowledge concerning central vestibular pathways is derived from animal studies while evidence of the functional importance and localization of these pathways in humans is less well defined. The termination of these pathways at the thalamic level in humans is even less known. In this review we summarize the findings concerning the central subcortical vestibular pathways in humans and the role of these structures in the central vestibular system with regard to anatomical localization and function. Also, we review the role of the thalamus in the pathogenesis of higher order sensory deficits such as spatial neglect, pusher syndrome or thalamic astasia and the correlation of these phenomena with findings of a vestibular tone imbalance at the thalamic level. By highlighting thalamic structures involved in vestibular signal processing and relating the different nomenclatures we hope to provide a base for future studies on thalamic sensory signal processing. [ABSTRACT FROM AUTHOR]

Abstract: Isolated cases of astasia or ptosis have each been reported in ischemic or hemorrhagic strokes involving the thalamus. We report a 70-year-old man with a medical history of hypertension who presented with left ptosis and gait disturbance despite intact motor strength in the legs and normal sensory function. MRI of the brain showed an evolving subacute infarction confined to the anteromedial-medial part of the left thalamus with no other areas of recent infarction identified. To our knowledge, combined ptosis and astasia in thalamic infarction has not been reported in the English literature. We identified 11 patients with thalamic ptosis and 21 with thalamic astasia in the literature. Patients who had ptosis, or gait abnormality which would not be related to thalamic stroke, were excluded; for example, evidence of infarction in the hypothalamus, midbrain, pons, cerebellum, or cingulate gyrus. [Copyright &y& Elsevier]

Summary: Sequence comparisons and a revised classification of the Euglenophyceae were based on 92 new SSU rDNA sequences obtained from strains of Euglena, Astasia, Phacus, Trachelomonas, Colacium, Cryptoglena, Lepocinclis, Eutreptia, Eutreptiella and Tetreutreptia. Sequence data also provided molecular signatures for taxa from genus to class level in the SSU rRNA secondary structure, revealed by a novel approach (search for non-homoplasious synapomorphies) and used for taxonomic diagnoses. Photosynthetic euglenoids and secondary heterotrophs formed a clade, designated as Euglenophyceae (emend.) with two orders: Euglenales and Eutreptiales. The mostly marine Eutreptiales (Eutreptia, Eutreptiella; not Distigma) comprised taxa with two or four emergent flagella (the quadriflagellate Tetreutreptia was integrated within Eutreptiella). The Euglenales (freshwater genera with ≤ one emergent flagellum) formed nine clades and two individual branches (single strains); however, only two clades were congruent with traditional genera: Trachelomonas (incl. Strombomonas) and Colacium. Euglena was polyphyletic and diverged into four independent clades (intermixed with Astasia, Khawkinea and Lepocinclis) and two individual branches (e.g. E. polymorpha). Phacus was also subdivided into Phacus s. str. and two combined lineages (mixed with Lepocinclis spp. or Cryptoglena). In consequence, Euglena (s. str.), Phacus and other genera were emended and one lineage (mixed Phacus/Lepocinclis-clade) was recognized as the previously neglected genus Monomorphina Mereschkowsky (1877). The sister clade of Phacus s. str. (mixed Euglena/Lepocinclis-clade) was identified as Lepocinclis Perty (emended). [Copyright &y& Elsevier]

Almost since the creation of the genus Euglena (Ehrenberg), the taxa assigned to it have been separated, split apart, and reorganized into new genera based on morphological relationships, resulting in the creation of the genera Phacus (Dujardin), Lepocinclis (Perty), Astasia (Pringsheim), and Khawkinea ( Jahn and McKibben) based on intuitive methods. In an effort to assess the validity of these genera, we have used small subunit (SSU) rDNA data to generate a phylogenetic framework for these genera, with particular attention to the genus Euglena. Using the conserved sequence areas, we performed a phylogenetic analysis using parsimony, maximum likelihood, and distance methods. These different criteria have resulted in trees of the same topology. The euglenoid clade was composed of phagotrophic euglenoids at the base, which gave rise to phototrophs that in turn gave rise to osmotrophs. Among the photosynthetic taxa, the biflagellate form diverged prior to the uniflagellate form. Additionally, the need for a revision in the taxonomy of some of these genera was demonstrated. Currently, taxa from the photosynthetic genera Euglena, Phacus, and Lepocinclis do not form monophyletic clades, but are intermixed with each other as well as with the osmotrophic taxa, Astasia and Khawkinea. [ABSTRACT FROM AUTHOR]

Objective: To present a case with nonalcoholic Wernicke’s encephalopathy (WE) developing astasia and optic neuropathy as major sequelae. Clinical Presentation and Intervention: A 47-year-old woman developed WE following operation for pyloric stenosis. She received total parenteral nutrition before and after operation, but on the second postoperative day she developed visual hallucination and confusion, followed by nystagmus, ophthalmoplegia, apathy, dysarthria and coma. Although the patient has recovered with thiamine treatment, astasia and optic neuropathy persistedas major morbidities. Conclusion: The report shows that astasia and optic neuropathy may be prominent sequelae in some patients with WE. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Astasia, inability to stand unsupported despite good strength, resembles the marked balance impairment of patients with vestibulocerebellar disease. We describe a patient with unilateral thalamic infarct that presented with astasia. A 76-year-old hypertensive woman was admitted to our hospital because of marked unsteadiness. On neurological examination, she could not stand unsupported and the woman's body swayed back and forth markedly. The swaying was not compensated for by her taking a step forward or backward, and she frequently collapsed when support was withdrawn. Diffusion-weighted magnetic resonance image revealed a discrete infarct within the right posterolateral thalamus. Brain single photon emission computerized tomography revealed markedly decreased regional cerebral blood flow within in the right thalamus with concomitant left superior cerebellar region. We discuss the possible pathomechanisms of thalamic astasia. [ABSTRACT FROM AUTHOR]

Astasia, the inability to stand and walk, in the absence of weakness or ataxia, is uncommon and unique. This syndrome is easy to misdiagnose as vestibulocerebellar disease. We report a patient with anterior callosal and cingulate infarction presenting as isolated astasia. A 65-year-old hypertensive man was admitted to our hospital with marked truncal instability. On neurological examination, he was unable to stand and walk independently. When asked to stand up from a sitting position, he had to grasp something nearby to propel himself upwards, and could not use his axial muscles. He collapsed when support was withdrawn. The patient showed no signs of amnesia, aphasia, apraxia or hemiasomatognosia. Diffusion weighted imaging at 3 days after onset demonstrated an acute infarct in the anterior part of the right-sided corpus callosum and cingulate gyrus. Magnetic resonance angiography revealed an occlusion of the right anterior cerebral artery. We discuss the possible mechanisms of astasia due to anterior callosal and cingulate infarction. [ABSTRACT FROM AUTHOR]

Abstract: We report a patient who presented with sudden onset instability and diplopia. On neurological examination he had asymmetrical asterixis, predominantly in the left hand, and ocular findings consistent with a pretectal syndrome. He was also unable to stand or even sit up unassisted, with a tendency to tilt his body and rotate his trunk axis to the left. Brain MRI showed a hemorrhage in the right thalamo-mesencephalic junction. This region involves important structures for the control of postural stability, motor control, ocular movements and vestibulo-ocular integration, not yet well understood. To our knowledge, this is the first reported case with the simultaneous combination of astasia, prectectal syndrome and asymmetrical asterixis. [Copyright &y& Elsevier]

A 73-year-old woman with essential hypertension and diabetes mellitus abruptly developed astasia. There were no other neurological abnormalities. Cranial diffusion-weighted magnetic resonance imaging demonstrated a localized infarction in the right-sided suprathalamic white matter. Under antiplatelet agent and rehabilitation, the patient became asymptomatic within 4 days. This is a first reported case of isolated astasia due to a suprathalamic white matter infarction. We speculated that disruption of the connection from the ventrolateral nucleus of the thalamus to the posterior cingulate gyrus and/or supplementary motor area might cause astasia.