Αρχειοθήκη ιστολογίου

Αλέξανδρος Γ. Σφακιανάκης
ΩτοΡινοΛαρυγγολόγος
Αναπαύσεως 5
Άγιος Νικόλαος Κρήτη 72100
2841026182
6032607174

Πέμπτη 27 Ιανουαρίου 2022

Modulation Depth Discrimination by Cochlear Implant Users

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Abstract

Cochlear implants (CIs) convey the amplitude envelope of speech by modulating high-rate pulse trains. However, not all of the envelope may be necessary to perceive amplitude modulations (AMs); the effective envelope depth may be limited by forward and backward masking from the envelope peaks. Three experiments used modulated pulse trains to measure which portions of the envelope can be effectively processed by CI users as a function of AM frequency. Experiment 1 used a three-interval forced-choice task to test the ability of CI users to discriminate less-modulated pulse trains from a fully modulated standard, without controlling for loudness. The stimuli in experiment 2 were identical, but a two-interval task was used in which participants were required to choose the less-modulated interval, ignoring loudness. Catch trials, in which judgements based on level or modulation depth would give opposing answers, were included. Experiment 3 employed novel stimuli whose modulation envelope could be modified below a variable point in the dynamic range, without changing the loudness of the stimulus. Overall, results showed that substantial portions of the envelope are not accurately encoded by CI users. In experiment 1, where loudness cues were available, participants on average were insensitive to changes in the bottom 30% of their dynamic range. In experiment 2, where loudness was controlled, participants appeared insensitive to changes in the bottom 50% of the dynamic range. In experiment 3, participants were insensitive to changes in the bottom 80% of the dynamic range. We discuss potential reasons for this insensitivity and implications for CI speech-processing strategies.

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A dose-neutral image quality comparison of different CBCT and CT systems using paranasal sinus imaging protocols and phantoms

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Eur Arch Otorhinolaryngol. 2022 Jan 27. doi: 10.1007/s00405-022-07271-4. Online ahead of print.

ABSTRACT

PURPOSE: To compare the image quality produced by equivalent low-dose and default sinus imaging protocols of a conventional dental cone-beam computed tomography (CBCT) scanner, an extremity CBCT scanner and a clinical multidetector computed tomography (MDCT) scanner.

METHODS: Three different phantoms were scanned using dose-neutral ultra-low-dose and low-dose sinus imaging protocols, as well as default sinus protocols of each device. Quantified parameters of image quality included modulation transfer function (MTF) to characterize the spatial response of the imaging system, contrast-to-noise ratio, low contrast visibility, image uniformity and Hounsfield unit accuracy. MTF was calculated using the line spread and edge spread functions (LSF and ESF).

RESULTS: The dental CBCT had superior performance over the extremity CBC T in each studied parameter at similar dose levels. The MDCT had better contrast-to-noise ratio, low contrast visibility and image uniformity than the CBCT scanners. However, the CBCT scanners had better resolution compared to the MDCT. Accuracy of HU values for different materials was on the same level between the dental CBCT and MDCT, but substantially poorer performance was observed with the extremity CBCT.

CONCLUSIONS: The studied dental CBCT scanner showed superior performance over the studied extremity CBCT scanner when using dose-neutral imaging protocols. In case a dental CBCT is not available, the given extremity CBCT is still a viable option as it provides the benefit of high resolution over a conventional MDCT.

PMID:35084532 | DOI:10.1007/s00405-022-07271-4

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Comparison of Outcomes of Surgical Repair of Spontaneous Temporal Bone CSF Leaks and Encephaloceles Using Bone Cement and Autologous Material

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Otol Neurotol. 2022 Jan 27. doi: 10.1097/MAO.0000000000003467. Online ahead of print.

ABSTRACT

OBJECTIVE: To compare outcomes transmastoid repair of spontaneous middle fossa cerebrospinal fluid (CSF) leak using only bone cement (BC) versus only autologous material (AM) or combined materials (CM) with both bone cement and autologous material.

STUDY DESIGN: Retrospective Chart Review.

SETTING: Tertiary Care Hospital.

PATIENTS: Forty-three adult patients undergoing transmastoid repair of spontaneous middle fossa CSF leak between 2014 and 2020 (BC:12, AM:15, CR:16).

INTERVENTIONS: Cortical mastoidectomy, identification of defect, and repair with BC (Cranios® hydroxyapatite), AM (local bone, fascia, fat, and/or cartilage), or CM (Cranios® combined with autologous materials).

MAIN OUTCOME MEASURES: Successful repair without recurrent CSF leak or encephalocele throughout follow up.

RESULTS: Fifty-one percent of subjects were female. Mean age at repair was 58.6 years (SD 10.9). Mean BMI was 35.4 (SD 7.6; BC:36.3, AM:36.5, CM:33.6). Forty (93%) patients had successful repair without known recurrent CSF leak or encephalocele since surgery (BC:11, 91.6%; AM:14, 93.3%; CM:15, 93.8%; p = 0.49) over a mean length of follow up of 49.6 months (BC: 37.9, AM: 59.2, CR: 49.5). The difference in mean operative time amongst the groups was faster for patients using bone cement (BC: 100.2 min, AM: 182.8, CM: 133.2; p < 0.00001).

CONCLUSIONS: BC, AM, and CM techniques each demonstrate effective and sustained means of repair for middle fossa CSF leak and encephalocele, even in the presence of multiple defects. Use of isolated BC offers a significant decrease in operative time with a noninferior outcome. Active CSF leak at the time of surgery is associated with increased risk of recurrence.

PMID:35085113 | DOI:10.1097/MAO.0000000000003467

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Τετάρτη 26 Ιανουαρίου 2022

Outcomes in surgical management of sinonasal malignancy—A single comprehensive cancer center experience

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Abstract

Background

Sinonasal malignancies are a complex and diverse group of tumors. Over the past five decades, treatment advances have changed the management paradigms for these tumors. Our aim was to analyze the outcomes of patients from a comprehensive cancer center.

Materials and Methods

We retrospectively assessed 400 patients with sinonasal malignancies treated with surgery at our center between 1973 and 2015. Multiple variables were reviewed to assess the influence on 5-year outcomes.

Results

The median age was 56 years (IQR 46.8–68). Two hundred and fifty-nine (65%) were males and 141 (35%) were females. Overall survival (OS) and disease-specific survival (DSS) improved in the last analyzed decade. Orbital invasion, advanced pT-classification and pN-classification, and melanoma histology were associated with poorer outcomes.

Conclusion

Treatment outcomes for patients with sinonasal malignancy have improved over time. This is likely multifactorial with advances in surgical technique, adjuvant treatment, and patient selection. pT-classification, pN-classification, orbital invasion, and histology are predictive of survival.

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Objective evaluation of stimulation artefact removal techniques in the context of neural spike sorting

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J Neural Eng. 2022 Jan 25. doi: 10.1088/1741-2552/ac4ecf. Online ahead of print.

ABSTRACT

Objective - We present a framework to objectively test and compare stimulation artefact removal techniques in the context of neural spike sorting. Approach - To this end, we used realistic hybrid ground-truth spiking data, with superimposed artefacts from in vivo recordings. We used the framework to evaluate and compare several techniques: blanking, template subtraction by averaging, linear regression, and a multi-channel Wiener filter (MWF). Main results - Our study demonstrates that blanking and template subtraction result in a poorer spike sorting performance than linear regression and MWF, while the latter two perform similarly. Finally, to validate the conclusions found from the hybrid evaluation framework, we also performed a qualitative analysis on in vivo recordings without artificial manipulations. Significance - Our framework allows direct quan tification of the impact of the residual artefact on the spike sorting accuracy, thereby allowing for a more objective and more relevant comparison compared to indirect signal quality metrics that are estimated from the signal statistics. Furthermore, the availability of a ground truth in the form of single-unit spiking activity also facilitates a better estimation of such signal quality metrics.

PMID:35078163 | DOI:10.1088/1741-2552/ac4ecf

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Chinese guidelines for diagnosis and treatment of allergic rhinitis (2022, revision)

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Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2022 Jan 21;57:8-31. doi: 10.3760/cma.j.cn115330-20211228-00828. Online ahead of print.

NO ABSTRACT

PMID:35078291 | DOI:10.3760/cma.j.cn115330-20211228-00828

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Chemosaturation with percutaneous hepatic perfusion of melphalan for metastatic uveal melanoma

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Purpose Uveal melanoma, the most common primary ocular malignancy in adults, carries a poor prognosis: 50% of patients develop the metastatic disease with a 10–25% 1-year survival and no established standard of care treatment. Prior studies of melphalan percutaneous hepatic perfusion (M-PHP) have shown promise in metastatic uveal melanoma (mUM) patients with liver predominant disease but are limited by small sample sizes. We contribute our findings on the safety and efficacy of the procedure in the largest sample population to date. Patients and methods retrospective analysis of outcome and safety data for all mUM patients receiving M-PHP was performed. Tumour response and treatment toxicity were evaluated using RECIST 1.1 and Common Terminology Criteria for Adverse Events v5.03, respectively. Results 250 M-PHP procedures were performed in 81 patients (median of three per patient). The analysis demonstrated a hepatic disease control rate of 88.9% (72/81), a hepatic response rate of 66.7% (54/81), and an overall response rate of 60.5% (49/81). After a median follow-up of 12.9 months, median overall progression-free (PFS) and median overall survival (OS) were 8.4 and 14.9 months, respectively. There were no fatal treatment-related adverse events (TRAE). Forty-three grade 3 (29) or 4 (14) TRAE occurred in 23 (27.7%) patients with a significant reduction in such events between procedures performed in 2016–2020 vs. 2012–2016 (0.17 vs. 0.90 per patient, P
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