1,720,985 research outputs found
The development of auditory perception in children after auditory brainstem implantation
No full textAuditory brainstem implants (ABIs) can provide useful auditory perception and language development in deaf children who are not able to use a cochlear implant (CI). We prospectively followed up a consecutive group of 64 deaf children up to 12 years following ABI surgery. The etiology of deafness in these children was: cochlear nerve aplasia in 49, auditory neuropathy in 1, cochlear malformations in 8, bilateral cochlear postmeningitic ossification in 3, neurofibromatosis type 2 in 2, and bilateral cochlear fractures due to a head injury in 1. Thirty-five children had other congenital nonauditory disabilities. Twenty-two children had previous CIs with no benefit. Fifty-eight children were fitted with the Cochlear 24 ABI device and 6 with the MedEl ABI device, and all children followed the same rehabilitation program. Auditory perceptual abilities were evaluated on the Categories of Auditory Performance (CAP) scale. No child was lost to follow-up, and there were no exclusions from the study. All children showed significant improvement in auditory perception with implant experience. Seven children (11%) were able to achieve the highest score on the CAP test; they were able to converse on the telephone within 3 years of implantation. Twenty children (31.3%) achieved open set speech recognition (CAP score of 5 or greater) and 30 (46.9%) achieved a CAP level of 4 or greater. Of the 29 children without nonauditory disabilities, 18 (62%) achieved a CAP score of 5 or greater with the ABI. All children showed continued improvements in auditory skills over time. The long-term results of ABI surgery reveal significant auditory benefit in most children, and open set auditory recognition in many
Auditory brainstem implantation after unsuccessful cochlear implantation of children with clinical diagnosis of cochlear nerve deficiency
No full textOBJECTIVES:
We compared the perceptual auditory abilities of 21 children with suspected cochlear nerve deficiency (CND) and a surgically verified absent cochlear nerve (CN) who first underwent cochlear implantation (CI) and subsequently underwent auditory brainstem implantation (ABI).
METHODS:
In this retrospective cohort study, from 2000 to 2011, 21 children initially underwent CI at an outside institution and failed to progress in their perceptual auditory abilities. Before CI, all of the children had severe to profound sensorineural hearing loss and a diagnosis of CND. Magnetic resonance imaging (MRI) documented an absent CN in 13 children and a small CN in 8 children. We performed explantation of the cochlear implant and simultaneous ABI on the same side. We performed MRI if no previous MRI results were available. All surgical videos were reviewed to determine the presence or absence of the CN. Measures of the patients' perceptual auditory abilities obtained after CI and after ABI were converted to the Category of Auditory Performance (CAP) scale.
RESULTS:
At surgery, all patients demonstrated an absent CN. After CI, all patients had a CAP score of 2 or less (mean, 0.52 +/- 0.68). After ABI, all patients had a CAP score of 2 or more (mean, 4.33 +/- 1.68); the improvement was statistically significant (p < 0.001). The complication rates were similar for CI and ABI.
CONCLUSIONS:
In this cohort of patients who had poor performance after CI, ABI achieved significantly improved performance as measured by the CAP and was shown to successfully rehabilitate hearing. Cases of a small CN may in reality represent an absent CN. Although this cohort was selected from patients with failed CI, the results have implications for the selection of device for patients with CND, in that ABI is a potential alternative to CI in select cases. In patients who fail to progress with intensive rehabilitation with CI or who have no progression in evoked auditory brainstem response, ABI must be considered early
Long-term outcome of round window vibrant soundbridge implantation in extensive ossicular chain defects
No full textObjective. To evaluate retrospectively the long-term safety and efficacy of the first 50 patients, all suffering from severe ossicular chain defects and with moderate to severe mixed hearing loss, who received the Vibrant SoundBridge with the floating mass transducer located on the round window membrane. To evaluate differences in outcome versus etiology and age of the patient population. Study Design. Case series with planned data collection. Setting. Tertiary referral medical center. Subjects and Methods. Patients eligible for implantation of the floating mass transducer on the round window membrane ranged in age from 2 months to 74 years with a moderate to severe conductive or mixed hearing loss from different etiologies. For each adult patient, preoperative versus postoperative bone and air conduction thresholds, air-bone gaps, and speech understanding scores were evaluated at 24-month follow-up. At 60-month follow-up, data were available from 33 patients. Preoperative and postoperative freefield auditory brainstem responses were studied in infants and children. Intraoperative and short- and long-term postoperative complications are presented. Results. There were significant improvements in speech perception and pure-tone audiometry in adults and auditory brainstem response thresholds in infants immediately after surgery and at follow-up examinations (12 to 71 months). No significant complications or device extrusions were observed in the present series. Conclusions. Infants, children, and adults with moderate to severe conductive or mixed hearing loss obtained substantial benefit from implantation of the floating mass transducer on the round window membrane regardless of the etiology of hearing loss and previous surgery
Electrocochleography during cochlear implantation for hearing preservation
No full textOBJECTIVE:
To determine whether intraoperative electrocochleography during cochlear implant surgery provides online feedback to modify surgical procedure, reduce trauma, and increase preservation of residual hearing.
STUDY DESIGN:
Prospective cohort study.
SETTING:
Tertiary referral center, Otolaryngology Department, University of Verona.
SUBJECTS AND METHODS:
Twenty-seven adult patients undergoing cochlear implant surgery who had low- to mid-frequency (0.25-2 kHz) auditory thresholds measured preoperatively were enrolled. Fifteen subjects had compound action potentials measured to assess cochlear function during surgery. In those patients, surgery was modified according to electrocochleographic feedback. Twelve control subjects underwent cochlear implant surgery with blinded electrocochleographic monitoring.
RESULTS:
The average preoperative pure-tone audiometry thresholds (0.25-2 kHz) were 74.3 ± 10.2 and 81.5 ± 12.7 dB hearing level (HL) in the electrocochleographic feedback and control cohorts, respectively (P > .05). Compound action potential recordings showed a mean maximum latency shift of 0.63 ± 0.36 ms and normalized amplitude deterioration of 59% ± 19% during surgery. All of these changes reverted to normal after electrode insertion in all but 1 subject in the electrocochleographic feedback group. The average shifts in postoperative pure-tone average threshold (0.25-2 kHz), evaluated before activation, were 8.7 ± 4.3 and 19.2 ± 11.4 dB HL in the electrocochleographic feedback and control cohorts, respectively (P = .0051). Complete hearing preservation (loss of ≤10 dB) at 1 month before activation was achieved in 85% (11/13) of electrocochleographic feedback subjects and in 33% (4/12) of control patients (P = .0154).
CONCLUSION:
Monitoring cochlear function with electrocochleography gives real-time feedback during surgery, providing objective data that might help in modifying the surgical technique in ways that can improve the rate of hearing preservation
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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