1,720,974 research outputs found
Auditory evoked responses (ABR, MLR, SVR) and brain mapping in the elderly
No full textThe influence of age on evoked auditory brainstem responses (ABRs) is still a matter of controversy. It is well known that in the elderly the ABRs show a progressive latency shift of the principal components. While many authors have reported a I-V internal latency shift, others claim that there is not a delay in the central conduction time (CCT) with ageing. Middle latency auditory evoked responses (MLRs) are also reported to be impaired in the elderly, but the few results published need further investigations. This study investigates some of the controversial aspects of electrophysiological assessment of the auditory system in the elderly. 36 healthy subjects (18 males and 18 females), mean age 67.2 years +/- 5.8, underwent ABRs, MLRs and SVRs and SVRs brain mapping evaluation. All the data were compared with our normative data for young adults. Our results confirm previous reports of a latency shift of all principal components of ABR, but do not demonstrate a significant CCT impairment in the elderly. The MLRs, SVRs and brain mapping analysis also support this conclusion
Branchio-oto-renal dysplasia and branchio-oto dysplasia: report of eight new cases
No full textEight new cases of "ear-pits-deafness syndrome" are reported here; in particular, the audiometric and tomographic findings of the ear and renal echography are discussed. Although it is difficult to give a nosologic definition of the syndrome, these cases can be classified as branchio-oto-renal dysplasia and branchio-oto dysplasia
Auditory brainstem evoked responses in the clinical evaluation and follow-up of insulin-dependent diabetic subjects
No full textIn the last few years the use of ABR in the dysmetabolic encephalopathies has aroused considerable interest. Even though brainstem involvement in these syndromes is not yet entirely understood, ABR techniques have provided new and important insights. We studied 60 insulin-dependent diabetic subjects, 29 females and 31 males aged to 17 to 55 yrs, and observed ABR abnormalities in 28.2% of the cases. This impairment affects the I-V interval or central transmission time (CTT), which is considered the most reliable index of brainstem function. The ABR pattern was considered pathologic when the CTT was due 2DS as compared with a sex- and age-matched control. Follow-up studies performed on 20 of these subjects revealed no significant variation in the ABR tracing. This fact, together with the absence or correlation between ABR involvement and metabolic control and glycemia level during the test, could be attributed to a 'structural' damage of the brainstem tissue. In diabetics, we observed a significant correlation (p less than 0.05) between I-V interval shift and an EMG-proved reduction in motor conduction velocity (MCV) of the peroneal nerve. We also found a high incidence of ABR impairment (53%) in diabetics with cardiovascular autonomic failure
Topographic brain mapping of middle latency auditory evoked potentials in normal subjects
No full textAuditory brainstem and middle latency evoked responses in the clinical evaluation of diabetes
No full textThe measurement of auditory brainstem evoked responses and middle latency evoked responses may improve the evaluation of diabetic neuropathy. Twenty diabetic patients were studied (12 males, 8 females), aged 21 to 63 years with normal hearing, together with 20 age- and sex-matched normal subjects (10 males, 10 females). Auditory brainstem evoked responses were induced by rarefaction clicks of 0.1 ms at a repetition rate of 21.1 CPS and an intensity of 75 dB hearing level. Middle latency evoked responses were induced with clicks of 0.1 ms, a repetition rate of 7.7 CPS and an intensity of 75 dB hearing level. Diagnostic criteria were: a I-V interval latency shift greater than 2SD of the control group for the auditory brainstem evoked response test or the interval difference of wave V greater than 0.2 ms. Middle latency evoked response was diagnostic if the latency of the Pa component was greater than 2SD of normals. Twenty-five per cent of subjects had retrocochlear impairment (absence of I wave) even in the absence of symptoms. The combined technique of auditory brainstem evoked response and middle latency evoked response improved the detection rate of central nervous system dysfunction. Auditory brainstem response is important for detecting desynchronization of the auditory response, whereas middle latency evoked response detects abnormalities in the more rostral regions of the central nervous system. In conclusion, there is a role for auditory brainstem evoked response and middle latency evoked response in the global assessment of diabetic neuropathy
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
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