1/9. Progressive dysarthria. case reports and a review of the literature.Two patients presenting with progressive dysarthria as the single initial manifestation of a neurodegenerative condition are described. The nature of the dysarthria as well as the additional symptoms that developed in the course of the disorder are very different in these two cases. Nevertheless, neuroimaging findings are strikingly similar and suggest bilateral involvement of posterior inferior frontal lobe structures, mainly in the dominant cerebral hemisphere. The clinical syndrome of these patients can therefore be considered an example of frontotemporal degeneration presenting without dementia or compartmental alteration, at least in the early stages. This broadens the clinical spectrum of frontotemporal degeneration and demonstrates the need for a syndromal subclassification of this nosological entity.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
2/9. Alien hand phenomena: a review with the addition of six personal cases.This is a comprehensive literature review of the motor abnormalities that have come to be included under the designation of Alien hand Phenomena (AHP). Some of the disorders are dyspractic in nature - intermanual conflict, mirror movements, interference etc., while others - groping, grasping with inability to release, utilization etc. are frontal lobe reflexes. AHP are mainly associated with two pathological processes: 1) infarction or hemorrhage in the territory of the anterior cerebral arteries; and 2) Corticobasal degeneration. Included in the review is a description of AHP in six personal cases of corticobasal degeneration. The summary includes a short discussion of the possible anatomy of 'free will' based on AHP.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
3/9. MR features of masticatory muscles in adenoid cystic carcinoma involving the masticator space.Adenoid cystic carcinoma (ACC) is known for its slow-growing but severely infiltrative nature with little tissue reaction. Although the masticatory muscles are often involved, their imaging features have not been well elucidated. We hereby report three patients with widespread ACC, which initially appeared with trismus and/or temporomandibular symptoms and involved the masticator space. Possible features of masticator space involvement are presented on magnetic resonance (MR) images. Masticatory muscle changes on MR images consisted of two aspects, namely, denervation changes and direct tumour invasion.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
4/9. Autoimmune paraneoplastic cerebellar degeneration: immunohistological localization of antibody-binding sites.Sera from 3 patients with breast or ovarian tumors and paraneoplastic cerebellar degeneration (PCD) contained anti-Purkinje cell antibodies (PCAbs) which also bind to other neurons on frozen sections of adult rodent brain. PCAbs tested on new-born rodent (rabbit, rat, mouse) brain tissue detected only oligodendrocyte-like cells (ODLC) in the white matter and allowed us to speculate on the nature of the antigenic structure in the neuronal cytoplasm. All these PCAbs appear histochemically identical and recognize antigens which belong to so-called "Yo" proteins.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
5/9. Progressive ideomotor apraxia: evidence for a selective impairment of the action production system.We report a patient with slowly progressive bilateral limb apraxia associated with an asymmetrical focal degenerative process of the parietal lobes. Clinical assessment of praxis production suggested a striking deficit in controlling the spatiotemporal attributes of purposeful skilled limb movements, consistent with ideomotor apraxia. The precise nature of the action production impairment was further defined by objective three-dimensional computergraphic analysis of transitive movements which demonstrated significant kinematic deficits in spatial accuracy, timing, spatiotemporal coupling, and joint coordination. Gesture comprehension and discrimination were spared. Furthermore, detailed evaluation of the conceptual praxis system revealed that despite an almost complete inability to perform transitive movements accurately, abstract knowledge of tool function and action was remarkably well preserved. The critical dissociation between intact conceptual knowledge of action and impaired movement execution documented in this case points to a fundamental competence/performance dichotomy in apraxia and provides empirical support for cognitive models of praxis that divide the action system into distinct conceptual and production subcomponents. Within this theoretical framework, our patient's severe ideomotor apraxia is interpreted to represent a selective disruption of the action production system.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
6/9. Sickle cells and sudden death: morphologic abnormalities of the cardiac conduction system.Sudden unexpected death has become increasingly recognized as an important clinical feature of both homozygous and heterozygous sickling syndromes, but the exact nature of its cause has remained unexplained. We have conducted special postmortem examinations of the cardiac conduction system and a coronary chemoreceptor from the hearts of two black males who had sickled erythrocytes. There were abundant foci of old and recent degeneration in the sinus node, atrioventricular node, and His bundle, as well as the coronary chemoreceptor. Many capillaries and small arteries were packed with sickled erythrocytes, among which small groups of aggregated platelets were also present. Focal fibromuscular dysplasia caused moderate to severe narrowing of many small coronary arteries, including those supplying the conduction system and chemoreceptor. These abnormalities are suggestive of electrical instability of the heart as at least one component of the lethal terminal events in some individuals with sickled erythrocytes. Both the foci of fibrosis and the focal fibromuscular dysplasia of small coronary arteries cannot be simply terminal or recent events but more likely take months or years in developing. For individuals with sickled erythrocytes, as in other examples of sudden death, there is a major element of chance concurrence of numerous otherwise independently less significant factors, but lethal cardiac electrical instability may be the final common pathway.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
7/9. Clinical and ultrastructural study of a sporadic case of hereditary sensory neuropathy. Morphological evidence for a slow rate fiber degeneration.A sporadic case of hereditary sensory neuropathy, with a clinical course and severe trophic and sensory alterations typical for type II, is presented. There was a severe loss of myelin in the sural nerve biopsy taken from the ankle. The most impressive microscopic feature was the number of rudimentary onion bulbs with an empty core which contained nude axons in the peripheral schwann cell layers; they were interpreted as vestigial structures left by the former myelinated fibers. Electron microscopy also revealed a definite involvement of unmyelinated fibers with attempted regeneration, which was confirmed by the overrepresentation of small axons on their frequency distribution curve. The whole ultrastructural picture suggested the protracted nature of the fiber involvement. This may be considered as agreeing with the slow course proposed for a system degeneration.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
8/9. vestibular nerve pathology in cases of intractable vertigo: an electronmicroscopic study.OBJECTIVE: This study aimed to determine the absence or presence and the nature of pathology of the vestibular nerve in case of intractable vertigo. STUDY DESIGN: This was a prospective study. SETTING: The study was performed at a private practice tertiary referral center. patients: There-were 42 patients with intractable vertigo in the study. INTERVENTIONS: All patients received thorough diagnostic examinations and surgical excision of the vestibular nerves. MAIN OUTCOME MEASURES: Segments of the superior and inferior vestibular nerves were surgically removed, preserved in glutaraldehyde, examined by electronmicroscopy, and the findings were correlated with the clinical diagnosis. RESULTS: A variety of different types of pathologic lesions were identified, including axon and supporting cell degeneration, herpes zoster virus, other viruses, results of bacterial infection, and regrowth of nerve after surgical resection. CONCLUSION: The vestibular nerves were found to be histologically normal in lesions primarily involving the end organ such as most early Meniere's disease cases, benign paroxysmal postural vertigo (BPPV), and mild labyrinthine concussion. Vestibular nerve degeneration was seen with advanced Meniere's disease, severe labyrinthine concussion, and with vascular loops in the internal auditory canal. Herpes zoster involves Scarpa ganglion in herpes zoster oticus. viruses were found in the nuclei of vestibular nerve cells in a patient with delayed hydrops. Regrowth of the vestibular nerve after surgical resection was confirmed in three cases.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
9/9. AAEM case report 32: nerve injury associated with hip arthroplasty.hip arthroplasty to alleviate pain related to arthritic degeneration has become one of the most common orthopedic procedures performed. As the elderly population expands, the number of such procedures can be expected to continue to increase. An electrodiagnostic evaluation can aid in localization, help identify the mechanism of injury, and be used as a tool to identify the nature and severity of the nerve pathology. electrodiagnosis can also be used to generate a prognosis for recovery from nerve damage following hip surgery.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |