1,720,970 research outputs found
The role of the periaqueductal grey in limbic and neocortical vocal fold control
No full textThe effects of a pharmacological blockade of the periaqueductal grey of the midbrain (PAG) on the elicitability of vocal fold movements from the facial motor cortex on the one hand and the anterior cingulate cortex and dorsomedial hypothalamus on the other were studied in the squirrel monkey. PAG blockade abolished vocal fold activity induced by the cingulate cortex and hypothalamus, but not that induced by the neocortex. These results point to the existence of two separate vocal fold control pathways at midbrain level: one limbic, responsible for non-verbal emotional vocal utterances, and one neocortical, responsible for the production of learned vocal patterns. The PAG represents a crucial relay station of the limbic but not the neocortical vocal control pathway
Progressive sensorineural hearing loss in children with mitochondrial encephalomyopathies
No full textObjective: Mitochondrial disorders are responsible for a variety of neurological syndromes. Specific mitochondrial DNA mutations have been identified recently in some of these rare disorders. Clinical symptoms may occur in different organs to various extent; often they are associated with progressive hearing loss. The aims of this study were to determine incidence, onset, and characteristics of hearing loss in children with mitochondrial encephalomyopathies and to investigate a possible correlation between the degree of hearing loss and neurological symptoms. In addition, we investigated the prognostic value of hearing loss as a predictor of the disease. Study Design: From August 1992 to September 1998, 29 patients ranging in age from 5 to 23 years (mean years) were studied. These children were hospitalized for diagnostic purposes in the neuropediatric department. Methods: The mitochondrial disorder was diagnosed by clinical and laboratory testings, including analysis of the mtDNA Audiological evaluation consisted of measurements of pure-tone and speech audiometry, tympanometry, and acoustic reflex threshold testing, auditory brainstem response, and evoked as well as distortion-product otoacoustic emissions. Results: A sensorineural hearing loss was identified in 12 children. Three of these were diagnosed as having classic Kearns-Sayre syndrome; five as having multisystem KSS; two as having the syndrome of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS); one as having KSS-MELAS overlap syndrome; and one as having Friedreich ataxia. Longitudinal testing was performed in seven children, and in all of them a progression of the hearing loss could be demonstrated. Audiological test results in all 12 children suggested cochlear as well as retrocochlear origin of the hearing loss presenting independently from the severity of hearing impairment. No correlation between the characteristics and degrees of hearing loss and the number and severity of clinical neurological symptoms could be found. Conclusions: The present study demonstrated a high incidence (42%) of sensorineural hearing loss in children with mitochondrial encephalomyopathies. The progressive nature of the hearing impairment was confirmed by a significant correlation between the duration in years and severity of hearing loss in the children. The hearing loss does not have a prognostic value for the progression of the disorder. Based on our findings, we recommend regular audiometric examinations in patients with mitochondrial disorders
Individual hemispheric asymmetry in vocal fold control of the squirrel monkey
No full textIn ten squirrel monkeys (Saimiri sciureus), electrodes were implanted into the left and right facial motor cortex at sites producing bilateral vocal fold adduction when electrically stimulated. All animals, in addition, had electrodes in the periaqueductal grey of the midbrain (PAC) at sites producing vocalization when electrically stimulated. In eight out of ten animals, motorcortical stimulation during periaqueductally elicited vocalization caused a change in vocal output. This change, in four cases, was more severe with left-sided ipsilateral motor cortex/PAG stimulation than with right-sided ipsilateral stimulation. In the other four cases, right-sided stimulation was more effective than left-sided stimulation It is concluded that the majority of squirrel monkeys show a hemispheric asymmetry in vocal fold control with left- and right-sided dominance distributed about equally in the population. (C) 2000 Elsevier Science B.V. All rights reserved
Do psychological factors change in patients with spasmodic dysphonia after injections with botulinum-toxin?
No full textObjective: A pre-/posttherapeutic comparative study was carried out to investigate possible associations of voice symptoms, selected psychological factors and their changing. Sample: A total of 11 patients with spasmodic dysphonia (adductor-type) subjected to botulinum-toxin-therapy. Patients had received treatment without any complications for at least 2 years. During that period of time, they received a minimum of 3 and a maximum of 9 injections (mean: 6). Methods: Psychosocial data were measured before and after treatment using standardized psychological methods. The time span between measurements ranged from 1;8 to 4:6 years, with an average of 2;1 years. Results: On average, no somatic disorder, no clinically meaningful states of anxiety or pathological manifestations of personality traits could be detected, neither pre- nor posttherapeutically. The average stress load caused by life-changing-events was unobtrusive. Before treatment, 5 of 11 patients had an affective disorder in terms of a depressed mood. This caused a higher than average mean depressivity score for the group as a whole. It was no longer found posttherapeutically. Conclusion: The depression is interpreted as a psychic reaction. An association between spasmodic voice symptoms and psychosocial genesis could not be proved
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
