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Background: Due to the coronavirus disease 2019 (COVID-19) pandemic, interventions in the upper airways are considered high-risk procedures for otolaryngologists and their colleagues. The purpose of this study was to evaluate limitations in hearing and communication when using a powered air-purifying respirator (PAPR) system to protect against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) transmission and to assess the benefit of a headset. Methods: Acoustic properties of the PAPR system were measured using a head and torso simulator. Audiological tests (tone audiometry, Freiburg speech test, Oldenburg sentence test (OLSA)) were performed in normal-hearing subjects (n = 10) to assess hearing with PAPR. The audiological test setup also included simulation of conditions in which the target speaker used either a PAPR, a filtering face piece (FFP) 3 respirator, or a surgical face mask. Results: Audiological measurements revealed that sound insulation by the PAPR headtop and noise, generated by the blower-assisted respiratory protection system, resulted in significantly deteriorated hearing thresholds (4.0 ± 7.2 dB hearing level (HL) vs. 49.2 ± 11.0
The cochlear implant (CI) represents, for almost 25 years now, the gold standard in the treatment of children born deaf and for postlingually deafened adults. These devices thus constitute the greatest success story in the field of ‘neurobionic’ prostheses. Their (now routine) fitting in adults, and especially in young children and even babies, places exacting demands on these implants, particularly with regard to the biocompatibility of a CI’s surface components. Furthermore, certain parts of the implant face considerable mechanical challenges, such as the need for the electrode array to be flexible and resistant to breakage, and for the implant casing to be able to withstand external forces. As these implants are in the immediate vicinity of the middle-ear mucosa and of the junction to the perilymph of the cochlea, the risk exists – at least in principle – that bacteria may spread along the electrode array into the cochlea. The wide-ranging requirements made of the CI in terms of biocompatibility and the electrode mechanism mean that there is still further scope – despite the fact that CIs are already technically highly sophisticated – for ongoing improvements to the properties of these implants and their constituent materials, thus enhancing the effectiveness of these devices. This paper will therefore discuss fundamental material aspects of CIs as well as the potential for their future development. Keywords: cochlear implant, biomaterials, biocompatibility, electrode, inner ear, cochleostomy, surface functionalization, drug delivery, nanoparticles, coating
Meeting Abstract : 82. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie. Freiburg i. Br., 01.-05.06.2011.
Ca. 3 Millionen Erwachsene in der Bundesrepublik Deutschland leiden unter Tinnitus, wobei eine bei jedem dieser Patienten zur Heilung führende Therapie bisher noch nicht existiert. Ansatzpunkt einer neuartigen Therapie ist die Wiederherstellung des normalen elektrischen Entladungsmusters im Hörnerv mittels elektrischer Stimulation. Hiermit berichten wir über unsere ersten Erfahrungen mit dem Tinnelec, einem Implantat mit einer einzelnen Stimulations-Elektrode die in der Rundfensternische platziert wird.
Zurzeit haben wir 4 einseitig ertaubten Patienten mit Tinnitus auf dem betroffenen Ohr jeweils ein Tinnelec-System implantiert. Die Dauer des Tinnitus betrug mindestens ein Jahr und gängige Tinnitus-Therapien wie z.B. Infusionstherapie waren erfolglos geblieben. Ein psychogener Tinnitus wurde ausgeschlossen. Der durch den Tinnitus verursachte Leidensdruck wurde anhand einer VAS Scala (Visuelle Analog Scala) und eines Tinnitus-Handicap-Inventory (THI) Fragebogens beurteilt. Die Reizapplikation betrug mind. 4 Stunden täglich. Als Stimulationsparameter wurde eine Reizmusterannäherung an den Tinnitus angestrebt.
Bei drei Patienten wurde unter der Stimulation der Tinnitus erträglicher, eine zeitweise komplette Unterdrückung des Tinnitus schon innerhalb der ersten Therapie-Wochen wurde jedoch nur in einem der Fälle berichtet. Diese Ergebnisse wurden auch durch das THI und VAS unterstützt.
Die Tinnelec-Implantation erscheint für Tinnitus Erfolg versprechend zu sein. Weitere Studien bei Tinnitus-Patienten ohne zusätzliche Hörbeeinträchtigung sind jedoch notwendig bis endgültige Schlussfolgerungen betreffend dieses Implantats gezogen werden können. In jedem Fall bleibt die Option einer Cochlea-Implantation im selben Ohr, nach Explantation des Tinnelec, bestehen.
Clinical speech perception tests with simple presentation conditions often overestimate the impact of signal preprocessing on speech perception in complex listening environments. A new procedure was developed to assess speech perception in interleaved acoustic environments of different complexity that allows investigation of the impact of an automatic scene classification (ASC) algorithm on speech perception. The procedure was applied in cohorts of normal hearing (NH) controls and uni- and bilateral cochlear implant (CI) users. Speech reception thresholds (SRTs) were measured by means of a matrix sentence test in five acoustic environments that included different noise conditions (amplitude modulated and continuous), two spatial configurations, and reverberation. The acoustic environments were encapsulated in a randomized, mixed order single experimental run. Acoustic room simulation was played back with a loudspeaker auralization setup with 128 loudspeakers. 18 NH, 16 unilateral, and 16 bilateral CI users participated. SRTs were evaluated for each individual acoustic environment and as mean-SRT. Mean-SRTs improved by 2.4 dB signal-to-noise ratio for unilateral and 1.3 dB signal-to-noise ratio for bilateral CI users with activated ASC. Without ASC, the mean-SRT of bilateral CI users was 3.7 dB better than the SRT of unilateral CI users. The mean-SRT indicated significant differences, with NH group performing best and unilateral CI users performing worse with a difference of up to 13 dB compared to NH. The proposed speech test procedure successfully demonstrated that speech perception and benefit with ASC depend on the acoustic environment.
Objectives: Combined electric-acoustic stimulation (EAS) is a well-accepted therapeutic treatment for cochlear implant (CI) users with residual hearing in the low frequencies but severe to profound hearing loss in the high frequencies. The recently introduced SONNETeas audio processor offers different microphone directionality (MD) settings and wind noise reduction (WNR) as front-end processing. The aim of this study was to compare speech perception in quiet and noise between two EAS audio processors DUET 2 and SONNETeas, to assess the impact of MD and WNR on speech perception in EAS users in the absence of wind. Furthermore, subjective rating of hearing performance was registered.
Method: Speech perception and subjective rating with SONNETeas or DUET 2 audio processor were assessed in 10 experienced EAS users. Speech perception was measured in quiet and in a diffuse noise setup (MSNF). The SONNETeas processor was tested with three MD settings omnidirectional/natural/adaptive and with different intensities of WNR. Subjective rating of auditory benefit and sound quality was rated using two questionnaires.
Results: There was no significant difference between DUET 2 and SONNETeas processor using the omnidirectional microphone in quiet and in noise. There was a significant improvement in SRT with MD settings natural (2.2 dB) and adaptive (3.6 dB). No detrimental effect of the WNR algorithm on speech perception was found in the absence of wind. Sound quality was rated as “moderate” for both audio processors.
Conclusions: The different MD settings of the SONNETeas can provide EAS users with better speech perception compared to an omnidirectional microphone. Concerning speech perception in quiet and quality of life, the performance of the DUET 2 and SONNETeas audio processors was comparable.
Objective: Sensorineural hearing loss leads to the progressive degeneration of spiral ganglion cells (SGC). Next to postoperative fibrous tissue growth, which should be suppressed to assure a close nerve–electrode interaction, the density of healthy SGC is one factor that influences the efficiency of cochlear implants (CI), the choice of treatment for affected patients. Rolipram, a phosphodiesterase-4 inhibitor, has proven neuroprotective and anti-inflammatory effects and might also reduce SGC degeneration and fibrosis, but it has to pass the cellular membrane to be biologically active.
Methods: Lipidic nanocapsules (LNC) can be used as biodegradable drug carriers to increase the efficacy of conventional application methods. We examined the biological effects of rolipram and LNC's core encapsulated rolipram on SGC and dendritic cell (DC) tumor necrosis factor-α (TNF-α) production in vitro and on SGC survival in systemically-deafened guinea pigs in vivo.
Results: Our results prove that rolipram does not have a beneficial effect on cultured SGC. Incorporation of rolipram in LNC increased the survival of SGC significantly. In the DC study, rolipram significantly inhibited TNF-α in a dose-dependent manner. The rolipram-loaded LNC provided a significant cytokine inhibition as well. In vivo data do not confirm the in vitro results.
Conclusion: By transporting rolipram into the SGC cytoplasm, LNC enabled the neuroprotective effect of rolipram in vitro, but not in vivo. This might be due to dilution of test substances by perilymph or an inadequate release of rolipram based on differing in vivo and in vitro conditions. Nevertheless, based on in vitro results, proving a significantly increased neuronal survival when using LNC-rolipram compared to pure rolipram and pure LNC application, we believe that the combination of rolipram and LNC can potentially reduce neuronal degeneration and fibrosis after CI implantation. We conclude that rolipram is a promising drug that can be used in inner ear therapy and that LNC have potential as an inner ear drug-delivery system. Further experiments with modified conditions might reveal in vivo biological effects.
Degeneration of neurons, such as the inner ear spiral ganglion neurons (SGN), may be decelerated or even stopped by neurotrophic factor treatment, such as brain-derived neurotrophic factor (BDNF), as well as electrical stimulation (ES). In a clinical setting, drug treatment of the SGN could start directly during implantation of a cochlear implant, whereas electrical stimulation begins days to weeks later. The present study was conducted to determine the effects of consecutive BDNF and ES treatments on SGN density and electrical responsiveness. An electrode drug delivery device was implanted in guinea pigs 3 weeks after deafening and five experimental groups were established: two groups received intracochlear infusion of artificial perilymph (AP) or BDNF; two groups were treated with AP respectively BDNF in addition to ES (AP + ES, BDNF + ES); and one group received BDNF from the day of implantation until day 34 followed by ES (BDNF ⇨ ES). Electrically evoked auditory brainstem responses were recorded. After one month of treatment, the tissue was harvested and the SGN density was assessed. The results show that consecutive treatment with BDNF and ES was as successful as the simultaneous combined treatment in terms of enhanced SGN density compared to the untreated contralateral side but not in regard to the numbers of protected cells.
Objectives: In this study, localization accuracy and sensitivity to acoustic interaural time differences (ITDs) in subjects using cochlear implants with combined electric-acoustic stimulation (EAS) were assessed and compared with the results of a normal hearing control group. Methods: Eight CI users with EAS (2 bilaterally implanted, 6 unilaterally implanted) and symmetric binaural acoustic hearing and 24 normal hearing subjects participated in the study. The first experiment determined mean localization error (MLE) for different angles of sound incidence between ± 60° (frontal and dorsal presentation). The stimuli were either low-pass, high-pass or broadband noise bursts. In a second experiment, just noticeable differences (JND) of ITDs were measured for pure tones of 125 Hz, 250 Hz and 500 Hz (headphone presentation). Results: Experiment 1: MLE of EAS subjects was 8.5°, 14.3° and 14.7°, (low-, high-pass and broadband stimuli respectively). In the control group, MLE was 1.8° (broadband stimuli). In the differentiation between sound incidence from front and back, EAS subjects performed on chance level. Experiment 2: The JND-ITDs were 88.7 μs for 125 Hz, 48.8 μs for 250 Hz and 52.9 μs for 500 Hz (EAS subjects). Compared to the control group, JND-ITD for 125 Hz was on the same level of performance. No statistically significant correlation was found between MLE and JND-ITD in the EAS cohort. Conclusions: Near to normal ITD sensitivity in the lower frequency acoustic hearing was demonstrated in a cohort of EAS users. However, in an acoustic localization task, the majority of the subjects did not reached the level of accuracy of normal hearing. Presumably, signal processing time delay differences between devices used on both sides are deteriorating the transfer of precise binaural timing cues.
Background: With the aging population and a rising incidence of squamous cell carcinoma of the head and neck (SCCHN), there is an emerging need for developing strategies to treat elderly patients.
Patients and Methods: We retrospectively analyzed 158 patients treated with definitive, concurrent chemoradiotherapy (CRT) for SCCHN. Clinicopathological characteristics, acute toxicities, and oncological outcomes were compared between patients younger and older than (or of age equal to) 65, 70, and 75 years.
Results: RT dose, chemotherapy regimen, and total chemotherapy dose were balanced between the groups. After a median follow-up of 29 months, overall survival (OS), progression-free survival (PFS), local control rate, and distant metastasis-free survival stratified by age of ≥65, ≥70, or ≥75 years revealed no differences. The rate of acute toxicities was also not higher for older patients. Worse ECOG performance score (ECOG 2-3) was associated with impaired OS () and PFS ().
Conclusion: Definitive treatment with CRT for SCCHN is feasible and effective; even in advanced age treatment decisions should be made according to general condition and comorbidity, rather than calendar age alone.
One challenge of squamous cell carcinoma of the head and neck (SCCHN) chemotherapy is a small percentage of tumor cells that arrest in the G0 phase of the cell cycle and are thus not affected by chemotherapy. This could be one reason for tumor recurrence at a later date. The recruitment of these G0-arresting cells into the active cell cycle and thus, proliferation, may increase the efficacy of chemotherapeutic agents. The aim of this study was to investigate whether stimulation with recombinant epidermal growth factor (EGF) or serotonin leads to an increased tumor cell proliferation in xenografts. Detroit 562 cells were injected into NMRI-Foxn1nu mice. Treatment was performed with 15 µg murine or human EGF, or 200 µg serotonin. The control mice were treated with Lactated Ringer's solution (5 mice/group). Tumor size was measured on days 4, 8 and 12 after tumor cell injection. The EGF stimulated mice showed a significantly higher tumor growth compared to the serotonin-stimulated mice and the untreated controls. In the present study, we show that it is possible to stimulate tumor cells in xenografts by EGF and thus, enhance cell proliferation, resulting in a higher tumor growth compared to the untreated control group. In our future investigations, we plan to include a higher number of mice, an adjustment of the EGF dosage and cell subanalysis, considering the heterogeneity of SCCHN tumors.