Matching the pitch perception of the cochlear implanted ear with the contralateral ear in patients with single-sided deafness: a novel approach.

PURPOSE: Single-sided deaf patients following cochlear implantation often compare the sound quality of their implanted ear with normal hearing. The interaural differences can result in dissatisfaction with speech comprehension and reduced time of usage of the speech processor; hence, prolonging auditory adaptation time. The proposed calibration method presented in this study demonstrates how the frequency distribution of the cochlear implant can be set to adequately approximate the pitch perception of the contralateral normal hearing ear towards improving speech intelligibility in a noisy environment. METHODS: In 12 postlingual single-sided deaf patients, subjective interaural pitch-matching was carried out to determine new central frequencies for the reallocation of the frequency bands of their speech processor (CP910, CP950 or CP1000, Cochlear, Australia). The patients were asked to compare the pitch of the tones presented to their normal hearing ear to the pitch of individual channels of their cochlear implant (CI522 or CI622, Cochlear, Australia). A third-degree polynomial curve was fit to the acquired matching frequencies to create the new frequency allocation table. Audiological measurements (free-field aided thresholds, speech reception thresholds, and monosyllabic word recognition score) in noise, together with a Speech, Spatial and Qualities of Hearing Scale (SSQ12) questionnaire (short version of the original SSQ) results were evaluated prior to the pitch-matching procedure, and again, 2 weeks later. RESULTS: The free-field aided thresholds of the patients showed no greater shift than ± 5 dB following the procedure; however, their monosyllabic word recognition score in noise improved significantly (mean - 9.58%, SD 4.98%, matched pairs t test comparison: p < 0.001). The results of the SSQ12 questionnaire also showed significant improvement in speech intelligibility, sound localization, and sound quality (mean 0.96 points, SD 0.45 points, matched pairs t test comparison: p < 0.001). CONCLUSIONS: Matching the pitch perception of the implanted cochlea with the sensation of the normal hearing contralateral ear, resulted in significant changes in the quality of hearing in patients with single-sided deafness. It is plausible the procedure can usher positive results in bimodal patients or following sequential bilateral cochlear implantation.

Thymosin beta-4 - A potential tool in healing middle ear lesions in adult mammals.

Acute tympanic membrane perforations primarily occur due to injury or infection in humans. In acute cases, nearly 80-94 % of the perforations heal spontaneously. In chronic cases, non-surgical treatment becomes significantly limited, and the perforation can be restored only by myringoplasty. In addition to classical grafts such as the fascia or cartilage, promising results have been reported with various biological materials including silk or acellular collagen. However, despite of all the efforts, healing remains insufficient. Consequentially, a need for substances which actively promote tympanic cell migration and proliferation is deemed essential. In our study, we utilized Thymosin beta-4 (TB4), a 43aa peptide possessing many regenerative properties in various organ systems. Our aim was to reveal the impact of externally administered TB4 regarding impairments of the middle ear, particularly the tympanic membrane. We harvested tympanic membranes from adult mice and treated these with TB4 or PBS on both collagen gel matrixes and in the form of floating, ex vivo explants. Cell migration and proliferation was measured, while immunocytochemical analyses were performed to determine cell type and the nature of the targeted molecules. We discovered the peptide affects the behavior of epidermal and epithelial cells of the tympanic membrane in vitro. Moreover, as our initial results imply, it is not the differentiated, yet most likely the local epidermal progenitor cells which are the primary targets of the molecule. Our present results unveil a new, thus far undiscovered field regarding clinical utilization for TB4 in the future.

Subtotal Petrosectomy and Cochlear Implantation in Children With Chronic Suppurative Otitis Media: A Single Institutional Experience.

BACKGROUND AND OBJECTIVES: Chronic suppurative otitis media (CSOM) with or without cholesteatoma is a frequent chronic inflammatory condition in children, which may lead to severe hearing loss that affects speech development. Treatment of recurrent CSOM associated with unserviceable hearing requires a specialized approach with regard to disease eradication and hearing rehabilitation. In this study, we investigated the advantages of subtotal petrosectomy (SP) combined with cochlear implantation (CI) in children with CSOM associated with unserviceable hearing and describe our experience with regard to the efficacy of this method, together with a literature review. SUBJECTS AND METHODS: SP with sequential or simultaneous CI was performed in three children (four ears), and postoperative audiometric data were recorded. RESULTS: The study included two male and one female patient. Mean age at the time of SP was 10.75 years (7-13 years). Sequential implantation was performed in three ears. Facial nerve palsy occurred after SP in one patient. The latest word recognition scores of Cases 1, 2, and 3 were 80% (at 60 dB), 75% (at 60 dB), and 70% (at 50 dB) and 90% (at 50 dB), respectively. CONCLUSIONS: SP with CI may be safe and reliable in children with CSOM associated with unserviceable hearing.

The ototoxic effect of locally applied kanamycin and furosemide in guinea pigs.

BACKGROUND: Hearing impairment is a growing social and economic issue. New technical or biological approaches aiming hearing rehabilitation or regeneration require animal testing. Therefore, a reproducible and safe model for hearing-impaired animals is essential. NEW METHOD: Intratympanic injection of kanamycin and furosemide was administered for BFA bunt pigmented guinea pigs for either 1 or 2 h. Hearing loss was regularly measured with compound action potential response to click and tone burst stimuli for up to 26 weeks. Hair cell loss and the density of spiral ganglion neurons were histologically analyzed. RESULTS: One week after the exposure, complete hearing loss was observed in 34 ears from the 36 ears treated for 2 h and remained stable during the follow-up. Histology revealed near complete hair cell loss and secondary degeneration of spiral ganglion neurons. COMPARISON WITH EXISTING METHODS: Animal deafening is usually achieved by systemic application of aminoglycoside antibiotics or chemotherapy drugs, although side effects such as nephrotoxicity may occur which can be avoided by local application. With our procedure, unilateral hearing loss model can also be established. CONCLUSIONS: The single intratympanic application of a solution of 200 mg/ml kanamycin and 50 mg/ml furosemide is a stable and reliable deafening method.

Staged surgical management of idiopathic sudden sensorineural hearing loss refractory to medical treatment / A gyógyszeres kezelésre nem javuló hirtelen halláscsökkenés lépcsozetes sebészi terápiája.

Összefoglaló. A hirtelen halláscsökkenés patofiziológiája még nagyrészt tisztázatlan, így oki terápia nem lehetséges. Az elsodleges kezelést a helyileg vagy szisztémásan adott kortikoszteroid jelenti, egységes protokoll azonban nem áll rendelkezésre. Nagy vagy súlyos fokú hirtelen halláscsökkenés esetén kóroki tényezoként felmerül a perilymphafistula lehetosége még azoknál a betegeknél is, akiknél nem szerepel trauma az anamnézisben. A kórkép mutéti kezelése a dobüreg feltárását követoen a belso fül ablakainak obliterálása. Amennyiben ez a megoldás nem eredményez megfelelo hallásjavulást, hagyományos vagy implantálható hallókészülékek alkalmazása javasolt. A közleményben részletezett esetünkben teljes siketséggel járó, jobb oldali hirtelen halláscsökkenés alakult ki, melynek hátterében egyértelmu okot azonosítani nem sikerült. Az eredménytelen kombinált, intratympanalis és szisztémás szteroidkezelést követoen exploratív tympanotomiát végeztünk, melynek során a belso fül ablakait obliteráltuk. Hallásjavulást ezt követoen sem sikerült kimutatni, így cochlearis implantáció elvégzése mellett döntöttünk. Az implantációt a kerek ablakon keresztül végeztük, mely alapján kijelenthetjük, hogy az elozetes kerekablak-obliteráció nem zárja ki a késobbi cochlearis implantációt. Orv Hetil. 2021; 162(51): 2055-2060. Summary. The pathophysiology of sudden sensorineural hearing loss is mainly unknown, therefore no causative treatment exists. Systemic and local administration of corticosteroids serves as first line therapy although protocols vary. In cases of severe or profound hearing loss with no improvement for medical therapy, perilymphatic fistulae can be assumed even without any history of trauma. Therefore, inner ear window obliteration as a primary surgical option in the early stage can be considered. For patients without complete recovery, conventional hearing aids or implantable hearing devices can be offered. In our case report, we present a patient with right sided idiopathic sudden deafness. After failure of conservative combined intratympanic and systemic steroid therapy, explorative tympanotomy and obliteration of the inner ear windows were performed. As no hearing improvement was witnessed, successful cochlear implantation via round window insertion was performed. Our case justifies that obliterating the round window membrane does not rule out further successful cochlear implantation. Orv Hetil. 2021; 162(51): 2055-2060.

Synthesis of Novel Crown Ether-Squaramides and Their Application as Phase-Transfer Catalysts.

This work presents the synthesis of six new phase-transfer organocatalysts in which the squaramide unit is directly linked to the nitrogen atom of an aza-crown ether. Four chiral skeletons, namely hydroquinine, quinine, cinchonine (cinchonas), and α-d-glucopyranoside were responsible for the asymmetric construction of an all-carbon quaternary stereogenic center in α-alkylation and Michael addition reactions of malonic esters. We investigated the effects of these different chiral units and that of crown ethers with different sizes on catalytic activity and enantioselectivity. During extensive parameter investigations, both conventional and emerging green solvents were screened, providing valuable α,α-disubstituted malonic ester derivatives with excellent yields (up to 98%).

Synthesis of Methyl 4,6-Di-O-ethyl-α-d-glucopyranoside-Based Azacrown Ethers and Their Effects in Asymmetric Reactions.

Carbohydrate-based crown ethers have been reported to be able to generate asymmetric induction in certain reactions. Previously, it was proved that the monosaccharide unit, the anomeric substituent, and the sidearm could influence the catalytic activity of the monoaza-15-crown-5 macrocycles derived from sugars. In order to gain information about the effect of the flexibility, 4,6-di-O-ethyl-glucoside-based crown compounds were synthesized, and their efficiency was compared to the 4,6-O-benzylidene analogues. It was found that the absence of the two-ring annulation has a negative effect on the enantioselectivity in liquid-liquid two-phase reactions: in the Darzens condensation of 2-chloroacetophenone and in the epoxidation of chalcone. The same trend was observed in the solid-liquid phase Michael addition of diethyl acetamidomalonate. Surprisingly, in the solid-liquid phase cyclopropanation of benzylidenemalononitrile, one of the new catalysts was highly enantioselective (99% ee).

Third window syndrome ­ classification, diagnosis, therapy / Harmadikablak-szindróma - osztályozás, diagnózis, terápia.

Összefoglaló. Halláspanasszal számos beteg fordul orvoshoz. A rutinszeruen elvégzett súgottbeszéd-, hangvilla- és tisztahangküszöb-audiometriai vizsgálat alapján vezetéses, sensorineuralis, illetve a ketto együttes fennállása esetén kevert típusú halláscsökkenést különböztetünk meg. Vezetéses halláscsökkenés létrejöhet mind a külso, mind a közép- vagy a belso fül veleszületett vagy szerzett rendellenességei esetén. Amennyiben a stapediusreflex kiváltható, ugyanakkor a betegnél nincs jelen a külso fület, valamint a középfület érinto kórfolyamat, felmerül a harmadikablak-szindróma lehetosége. A kórkép okaként egy, a belso fül csontos tokján "harmadik ablakként" funkcionáló laesio van jelen, amely az ovális ablakon keresztül beérkezo hangenergia egy részét elvezeti, mielott az a kerek ablakon át kivezetodik a középfülbe. A diagnózis felállítása gyakran nehéz feladat elé állítja a klinikust, melyhez a megfelelo audiológiai, illetve képalkotó vizsgálatok elvégzése elengedhetetlen. Tekintettel arra, hogy a panaszok megszüntetésére számos mutéti módszer került leírásra, közleményünkben átfogó képet adunk a kórkép etiológiájáról, diagnosztikájáról, terápiájáról, valamint bemutatjuk saját kezdeti tapasztalatainkat is 2 eset prezentálásával. Orv Hetil. 2020; 161(46): 1944-1952. Summary. Patients frequently present to the physician with hearing loss. Routine hearing tests include speech field (whisper test), tuning forks and pure tone threshold audiometry, which can identify the presence of sensorineural hearing loss, conductive hearing loss or a combination of both (mixed type). Conductive hearing loss can be a symptom of many different conditions. These include congenital or acquired malformations of the outer, middle and inner ear. If a conductive hearing loss with intact stapedial reflexes are recorded and in the absence of outer or middle ear pathology, then the third window syndrome should be considered. The cause is a bony defect on the otic capsule that acts as a 'third window', dissipating the incoming sound energy. Without the appropriate audiological and imaging tests, the diagnosis of the condition is challenging in clinical setting. Several surgical techniques have been described to treat the condition. The authors give a comprehensive review of the etiology, diagnosis and treatment of the disease presenting their initial experiences with 2 cases. Orv Hetil. 2020; 161(46): 1944-1952.

The first direct acoustic middle-ear implantation in Hungary / Az elso hazai direkt akusztikus középfül-implantáció

Due to the remarkable development in the field of hearing implantation, almost all kinds of hearing loss can be successfully rehabilitated. The first Hungarian Codacs™ (Cochlear's direct acoustic cochlear stimulator; Cochlear, Sydney, Australia) implantation was performed at the Department of Otorhinolaryngology and Head-Neck Surgery, Clinical Centre, University of Pécs. This electromechanical middle-ear implant can be offered for patients with bilateral, severe to profound, mixed-type hearing loss. In our case, a 67-year-old male patient with bilateral advanced otosclerosis was implanted, which led to significant improvement of the hearing threshold and speech reception. Orv Hetil. 2020; 161(24): 1015-1019.

[Subtotal petrosectomy - indications, surgical technique, experiences in Pécs]. / Subtotalis petrosectomia ­ javallatok, mutéti technika, pécsi tapasztalatok.

Introduction: Subtotal petrosectomy (STP) has been known for decades and it is considered being on the borderline between ear and skull-base surgery. Due to its excessive radicalism and adverse effects on hearing, it has been a forgotten surgical technique until recently. Over the last decade, due to its many benefits and the ability to combine it with modern hearing rehabilitation methods, STP has reappeared, providing a definitive solution to a number of problematic middl-ear disorders. Aim: In our retrospective clinical study, we wanted to highlight the effectiveness of STP, analyzing the efficiency of this surgery for the first time in domestic patient records, and to report our own experiences to date. Method: We processed data from 45 surgeries on our 44 patients. In addition to presenting the various surgical indications, we review the steps of the operation, analyze the audiological results, including the various methods of hearing rehabilitation, and also analyze the complications that have occurred. Our results are also summarized in the light of international professional literature. Results: Of our 44 patients, 23 were female and 21 were male. Patients had a mean age of 44.6 ± 20.5 years and a mean follow-up of 23 ± 16 months. Of our patients, 25 (57%) had undergone at least two previous unsuccessful ear operations, and 6 (14%) had deafness before surgery. The most common indication was chronic otitis media with cholesteatoma. 13 patients underwent 14 cochlear implantations (23%), in addition 6 patients received bone anchored hearing aids (BAHA) (14%), and 2 patients (5%) underwent VSB (Vibrant Soundbridge) placement against the round window membrane. Complications occurred in 11 of our patients, the most common of which was cerebrospinal fluid leak (5 cases, 11%) and wound dehiscence (3 cases, 7%). Data from 3 patients were available for processing the audiological results. Conclusion: STP is an extremely favorable surgical solution for a number of middle-ear pathologies that have previously caused major problems. The main reason for its growing popularity is that it can be combined with a number of modern, effective methods of hearing rehabilitation. Orv Hetil. 2020; 161(14): 544-553.

Stapedotomy with incus vibroplasty - A novel surgical solution of advanced otosclerosis and its place among existing therapeutic modalities - Hungarian single institutional experiences.

OBJECTIVE: To delineate the advantages and steps of stapedotomy with incus vibroplasty, to assess the safety and efficacy of this method via the authors' experiences, and to overview the literature regarding other surgical options in advanced otosclerosis determining the place of stapedotomy with incus vibroplasty in the therapeutic range. METHODS: Four patients were enrolled in the study presenting severe mixed hearing loss of at least one side on pure tone audiometry. Based on complementary audiological examinations including stapedial reflex test and multifrequency tympanometry, all cases were suspected as advanced otosclerosis. Stapedotomy with incus vibroplasty - the combination of laser stapedotomy and simultaneous Vibrant Soundbridge implantation - was performed in each patient. Preoperative pure tone average, speech recognition thresholds and word recognition scores were compared to one-year postoperative free-field values with the implant switched on focusing on functional gain. RESULTS: Among 4 participants (3 females, 1 male) the mean age (SD) was 66 years (35). In three cases Nitinol, in one case NitiBond piston was inserted. One-year postoperative free-field functional gains were 30 dB, 34 dB, 42 dB and 51 dB, respectively. One-year postoperative free-field speech recognition thresholds were 45 dB, 45 dB, 49 dB and 50 dB, respectively, while word recognition scores were 70%, 70%, 70% and 75%, respectively. CONCLUSION: Postoperative results in our serie regarding pure tone average and word recognition score proved to be better than those found in the literature. Stapedotomy with incus vibroplasty - through sufficient air-bone gap closure and simultaneous sensorineural component management - seems to be a promising surgical solution in advanced otosclerosis, requiring further investigation.

Synthesis of xylal- and arabinal-based crown ethers and their application as asymmetric phase transfer catalysts.

New xylal- and arabinal-based monoaza-15-crown-5 ethers were synthesized starting from l- and d-xylose, and l- and d-arabinose, respectively. These monosaccharide-based chiral macrocycles were tested as phase transfer catalysts in a few asymmetric reactions. The xylal-based crown compounds proved to be efficient catalysts in a few liquid-liquid phase reactions. The epoxidation of trans-chalcone and the Darzens condensation of α-chloroacetophenone with benzaldehyde took place with complete diastereoselectivity and up to 77% ee and 58% ee, respectively. It was found that the substituents in the aromatic ring of the chalcone and the α-chloroacetophenone had an influence on the enantioselectivity. The highest ee values were obtained in the epoxidation of 4-chlorochalcone (81% ee) and in the reaction of a 2-naphthyl analogue (96% ee), while in the Darzens condensation of 4-phenyl-α-chloroacetophenone with benzaldehyde, a maximum ee of 91% was detected. The configuration of the monosaccharide unit in the crown ring influenced the absolute configuration of the epoxyketones synthesized.

[First experiences with Cochlear Implant Function Index (CIFI) in Hungary]. / A Cochlearis Implantáltak Funkcionális Indexe (CIFI) magyarországi bevezetésével szerzett kezdeti tapasztalatok.

Introduction: The success of cochlear implantation can be evaluated with audiological measurements and quality of life questionnaires. Aim: Our aim was to translate and introduce the Cochlear Implant Function Index (CIFI) test to analyze the physical, psychological and social state of our cochlear implant patients. Method: Between 01. 11. 2016 and 31. 05. 2018, 30 patients filled the questionnaire before and 6 and 12 months after the implantation. Results and conclusion: Results showed a remarkable improvement in the quality of life in several patients even after 6 months. Further improvements could be measured after 12 months. Orv Hetil. 2019; 160(33): 1296-1303.

[Analysis of prognostic factors influencing the effectiveness of treatment in sudden sensorineural hearing loss]. / A hirtelen halláscsökkenés javulásában szerepet játszó prognosztikai faktorok vizsgálata.

Sudden sensorineural hearing loss is defined as a greater than 30 dB deterioration in at least 3 consecutive frequencies occurring within 72 hours. The disease is mostly idiopathic and needs an urgent treatment. Between 01. 01. 2015 and 31. 12. 2016, 149 patients with sudden hearing loss were admitted to the Department of Otorhinolaryngology, University of Pécs. The epidemiological data, the prognostic factors and the outcome of the treatment were retrospectively analyzed. Isolated high frequency (p = 0.012) and less severe hearing loss (p<0.001), older age (p = 0.005), comorbodities like cardiovascular disease (p = 0.009) and diabetes (p = 0.029) were found as negative prognostic factors. Time of introduction of the treatment, gender, and side of the affected ear did not influence the outcome. Our finding was mainly congruent to the literature. Orv Hetil. 2019; 160(18): 687-693.

[Modern management of otologic consequences of Wegener's granulomatosis - a case report and review of the literature]. / Wegener-granulomatosis talaján kialakult krónikus gennyes középfülgyulladás komplex kezelése.

Wegener's granulomatosis - or, in other words, granulomatosis with polyangiitis - is an anti-neutrophil cytoplasmic antibody associated granuloma forming vasculitis, mainly affecting the respiratory tract and the renal system. Otologic manifestations of Wegener's disease can be otitis media with effusion or chronic silent mastoiditis with conductive hearing loss, but sensorineural hearing loss can also evolve. The diagnosis is based on the clinical appearance as well as the immunoserological and histopathological results. It is of paramount importance to begin a combined immunosuppressive treatment immediately, besides eradicating the otologic manifestations. The intractable cases of chronic otitis media due to Wegener's granulomatosis are challenging any ear surgeons. Subtotal petrosectomy has proved to be an effective solution in such cases to create a dry ear and to provide a safe surgical field for hearing restoration. The authors reviewed the literature and report a case history to present the modern management of Wegener's granulomatosis with otologic manifestation. Orv Hetil. 2019; 160(4): 151-157.

[First report on successful application of nivolumab in Hungary for the treatment of locally recurrent head and neck squamous cell carcinoma]. / Immunterápia elsõ hatékony alkalmazása Magyarországon lokálisan kiújult fej-nyaki laphámkarcinómás betegnél.

The prognosis for recurrent/metastatic head and neck squamous cell cancer (R/M HNSCC) remains dismal and its treatment poses a challenge for oncologists. Nivolumab belongs to the class of immune checkpoint inhibitors (ICI) and is an antibody developed to target the programmed cell death protein 1 (PD-1) receptor. The CheckMate 141 randomized phase 3 trial proved the efficacy of nivolumab in the treatment of R/M HNSCC as it was shown to significantly increase overall survival and quality of life. We present the case of a 53-year-old woman with R/M HNSCC who was given nivolumab monotherapy, as third-line treatment due the progression of her tumor. After treatment with nivolumab, the size of her tumor decreased, then was stable, while she did not experience any adverse events or notable side effects. Our case report is the first to demonstrate the application of nivolumab in R/M HNSCC in Hungary.

Synthesis of d-mannitol-based crown ethers and their application as catalyst in asymmetric phase transfer reactions.

A few new d-mannitol-based monoaza-15-crown-5 type chiral lariat ethers and 18-crown-6 type macrocycles were synthesized. These crown compounds were used as phase transfer catalysts in asymmetric Michael addititons and in a Darzens condensation under mild conditions to afford the corresponding products in a few cases in good to excellent enantioselectivities. In the Michael addition of diethyl acetoxymalonate to trans-chalcone, in the addition of diethyl acetamidomalonate to ß-nitrostyrene, in the reaction of diethyl bromomalonate with benzylidene malononitriles, in the cyclopropanation reaction of diethyl bromomalonate and 2-benzylidene-1,3-indandione, and in the Darzens condensation of α-chloroacetophenone with benzaldehyde, maximum enantioselectivities of 39%, 65%, 99%, 56%, and 62%, respectively, were obtained in the presence of the d-mannitol-based macrocycles as the catalysts.

[Comparative evaluation of vertigo in patients after stapedotomy and stapedectomy]. / Posztoperatív vertigo vizsgálata stapedotomián és stapedectomián átesett betegeknél.

INTRODUCTION AND AIM: The reason of gradually developing conductive hearing loss in otosclerotic patients is the ossification of the stapes footplate to the surrounding bony structures and the therapy of stapes fixation is mainly surgical. In stapedotomy the footplate of the stapes is fenestrated with laser and microdrill in a diameter of 0.8 mm, whereas in stapedectomy there is complete removal of the footplate followed by the reconstruction of the ossicular chain. In the early postoperative period, temporary vertigo is frequently recorded which significantly influences the recovery. METHOD: In the Department of Otorhinolaryngology, University of Pécs both stapedectomy and stapedotomy were performed on a daily basis between 01.02.2010 and 15.03.2012. Our study focused on comparing the degree of postoperative vertigo after the two types of surgery. We hypothesized that the smaller fenestration of the stapes footplate during stapedotomy limits exposure to the inner ear reducing the severity of dizziness. Vertigo was evaluated subjectively with a retrospective questionnaire and objectively with static posturography. RESULTS: On the 1st postoperative day, significantly fewer patients reported vertigo in the stapedotomy group and with significantly lower intensity. Results of the questionnaire regarding the later postoperative period showed no significant differences between the groups. Based on the analysis of the posturography test results, no significant difference was detected between the postoperative stability of the two groups. Results of the questionnaire and the posturography showed no correlation. Posturography test results did not confirm the presence of subjective vertigo. CONCLUSION: Many factors may play a role in the development of vertigo after stapes surgery, but the type of intervention does not influence it. Orv Hetil. 2017; 158(38): 1503-1511.

NANOCI-Nanotechnology Based Cochlear Implant With Gapless Interface to Auditory Neurons.

: Cochlear implants (CI) restore functional hearing in the majority of deaf patients. Despite the tremendous success of these devices, some limitations remain. The bottleneck for optimal electrical stimulation with CI is caused by the anatomical gap between the electrode array and the auditory neurons in the inner ear. As a consequence, current devices are limited through 1) low frequency resolution, hence sub-optimal sound quality and 2), large stimulation currents, hence high energy consumption (responsible for significant battery costs and for impeding the development of fully implantable systems). A recently completed, multinational and interdisciplinary project called NANOCI aimed at overcoming current limitations by creating a gapless interface between auditory nerve fibers and the cochlear implant electrode array. This ambitious goal was achieved in vivo by neurotrophin-induced attraction of neurites through an intracochlear gel-nanomatrix onto a modified nanoCI electrode array located in the scala tympani of deafened guinea pigs. Functionally, the gapless interface led to lower stimulation thresholds and a larger dynamic range in vivo, and to reduced stimulation energy requirement (up to fivefold) in an in vitro model using auditory neurons cultured on multi-electrode arrays. In conclusion, the NANOCI project yielded proof of concept that a gapless interface between auditory neurons and cochlear implant electrode arrays is feasible. These findings may be of relevance for the development of future CI systems with better sound quality and performance and lower energy consumption. The present overview/review paper summarizes the NANOCI project history and highlights achievements of the individual work packages.