Neurochemical evidence of dopamine release by lateral olivocochlear efferents and its presynaptic modulation in guinea-pig cochlea

In this study, using an in vitro superfusion technique for the first time, we provide direct neurochemical evidence of the transmitter role of dopamine at the level of lateral olivocochlear efferent fibres of the guinea-pig cochlea. Our results revealed that nerve terminals are able to take up and release dopamine upon axonal stimulation. Since dopamine is thought to protect the afferent nerve fibres from damage due to acoustic trauma or ischaemia, enhancement of the release of dopamine, a potential therapeutic site of these injuries, was investigated. Positive modulation of dopamine release has been shown by a D1 dopamine receptor agonist, an antagonist and piribedil. Furthermore, negative feedback on the stimulation-evoked release of dopamine via D2 dopamine receptors has been excluded. Electrical stimulation of the cochlear tissue produced a significant and reproducible release of [3H]dopamine, which could be blocked by tetrodotoxin (1 microM) and cadmium (100 microM), proving that axonal activity releases dopamine and its dependence on Ca2+ influx verifies its neuronal origin. Nomifensine, a high-affinity dopamine uptake blocker, prevented the tissue from taking up [3H]dopamine from the bathing solution, also indicating the neural origin of dopamine released in response to stimulation. SKF-38393 (a selective D1 agonist) increased both the resting and electrically evoked release of dopamine. Piribedil (a D3/D2/D1 agonist), a drug under investigation, known to prevent acoustic trauma or ischaemia-induced hearing loss, had a similar and concentration-dependent increasing effect on both resting and evoked release of dopamine. The effect of both drugs on stimulation-evoked release could be prevented by SKF-83566 (a selective D1 antagonist). However, SKF-83566 alone enhanced the resting and axonal conduction-associated release of dopamine. D2 agonists and antagonists failed to modulate the release of dopamine, indicating the lack of negative feedback modulation of dopamine release. Our results suggest that the release of dopamine was subjected to modulation by a D1 receptor agonist and an antagonist. In addition, it is concluded that D2 receptors are not involved in the modulation of dopamine release. This observation may have clinical relevance in the prevention or therapy of particular types of hearing loss, because enhanced dopaminergic input into the primary auditory neuron may inhibit the (over)excitation of this neuron by glutamatergic input from inner hair cells.

Analysis of GJB2 mutations and the clinical manifestation in a large Hungarian cohort

PURPOSE

Pathogenic variants of the gap junction beta 2 (GJB2) gene are responsible for about 50% of hereditary non-syndromic sensorineural hearing loss (NSHL). In this study, we report mutation frequency and phenotype comparison of different GJB2 gene alterations in Hungarian NSHL patients.

METHODS

The total coding region of the GJB2 gene was analyzed with Sanger or NGS sequencing for 239 patients with NSHL and 160 controls.

RESULTS

Homozygous and compound heterozygous GJB2 mutations were associated with early onset serious clinical phenotype in 28 patients. In 24 patients, two deletion or nonsense mutations were detected in individuals with mainly prelingual NSHL. In compound heterozygous cases, a combination of deletion and missense mutations associated with milder postlingual NSHL. A further 25 cases harbored single heterozygous GJB2 mutations mainly associated with later onset, milder clinical phenotype. The most common mutation was the c.35delG deletion, with 12.6% allele frequency. The hearing loss was more severe in the prelingual groups.

CONCLUSION

The mutation frequency of GJB2 in the investigated cohort is lower than in other European cohorts. The most serious cases were associated with homozygous and compound heterozygous mutations. In our cohort the hearing impairment and age of onset was not altered between in cases with only one heterozygous GJB2 mutation and wild type genotype, which may exclude the possibility of autosomal dominant inheritance. In early onset, severe to profound hearing loss cases, if the GJB2 analysis results in only one heterozygous alteration further next generation sequencing is highly recommended.

Veratridine-evoked release of dopamine from guinea pig isolated cochlea

Dopamine released from the lateral olivocochlear efferent system is thought to inhibit the toxic effect of the extreme glutamate outflow from the inner hair cells during ischemia or acoustic trauma. Using in vitro microvolume superfusion, we have studied the release of [(3)H]dopamine from the lateral olivocochlear efferent bundle of guinea pig in response to accumulation of [Na(+)](i), under condition characteristics of ischemia. Veratridine, that acts only on excitable membranes as a specific activator of voltage-sensitive sodium channels, significantly increased the electrically evoked release of [(3)H]dopamine, which was completely inhibited by tetrodotoxin. Dizocilpine (MK-801), a non-competitive NMDA-receptor antagonist, and GYKI-52466, a selective non-NMDA-receptor antagonist, had no effect on veratridine-induced [(3)H]dopamine release. Our data provide further evidence that the cochlear release of dopamine is of neural origin and possibly independent on a local effect of glutamate. The veratridine-induced transmitter release in the cochlea will be a very useful method in studying the effect of drugs on ischemic injury.

Characterization of voltage dependent calcium channels on the lateral olivocochlear efferent fibers of the guinea pig

Using in vitro superfusion technique the release of [3H]-dopamine from the lateral olivocochlear efferent fibers of the cochlea was investigated. Our previous study gave the first neurochemical evidence for the transmitter role of dopamine and proved its neuronal origin. Using specific antagonists now we characterized the voltage-dependent calcium channels (VDCCs) involved in the release of dopamine evoked by electrical stimulation of the cochlear tissue. Verapamil or nifedipine, and Ni2+ failed to affect the release, indicating that neither L-, nor T-type VDCCs are essential for the release process. The fact that omega-conotoxin inhibited the release of dopamine from lateral olivocochlear efferent fibers suggests, that N-type VDCCs are required for the calcium influx during electrical stimulation. These VDCCs could be presynaptic targets of modulation of the dopamine release under pathological conditions or in therapy.

Simultaneous measurement of glutamate and dopamine release from isolated guinea pig cochlea

Glutamate is proved to be a neurotransmitter in the mammalian cochlea, transmitting signals between the inner hair cells and the afferent cochlear nerve terminals. The transmission in this synapse is modulated by the lateral olivocochlear efferent fibers by releasing dopamine and other neurotransmitters. This study undertakes to measure simultaneously the release of dopamine and glutamate from isolated guinea pig cochleae. We combined the in vitro microvolume superfusion method, that uses liquid scintillation analysis, to measure [3H]dopamine with high pressure liquid chromatography (HPLC) to determine the glutamate content of the superfusate at rest and during stimulation. The release of both neurotransmitters was significantly increased when electrical field stimulation was applied at a 10 Hz rate. The nonselective sodium-channel inhibitor tetrodotoxin (TTX) at 1 microM completely blocked the effect of stimulation, indicating the neural origin of both dopamine and glutamate. The dopamine receptor antagonist sulpiride at 100 microM and the dopamine receptor agonist bromocriptine at 20 microM did not change the release of glutamate. In contrast, both bromocriptine and sulpiride significantly increased the stimulation-evoked release of dopamine. The effect of sulpiride is most likely due to the blockade of dopamine autoreceptor. Possible explanations why bromocriptine increased the release include: (1) its partional agonist activity; (2) desensitizations of dopamine autoreceptors; or (3) the higher D1 receptor activity of bromocriptine than sulpiride. This study could provide further insights about the role of dopamine and glutamate in cochlear neurotransmission.

Chronic Oral Selegiline Treatment Mitigates Age-Related Hearing Loss in BALB/c Mice

Age-related hearing loss (ARHL), a sensorineural hearing loss of multifactorial origin, increases its prevalence in aging societies. Besides hearing aids and cochlear implants, there is no FDA approved efficient pharmacotherapy to either cure or prevent ARHL. We hypothesized that selegiline, an antiparkinsonian drug, could be a promising candidate for the treatment due to its complex neuroprotective, antioxidant, antiapoptotic, and dopaminergic neurotransmission enhancing effects. We monitored by repeated Auditory Brainstem Response (ABR) measurements the effect of chronic per os selegiline administration on the hearing function in BALB/c and DBA/2J mice, which strains exhibit moderate and rapid progressive high frequency hearing loss, respectively. The treatments were started at 1 month of age and lasted until almost a year and 5 months of age, respectively. In BALB/c mice, 4 mg/kg selegiline significantly mitigated the progression of ARHL at higher frequencies. Used in a wide dose range (0.15-45 mg/kg), selegiline had no effect in DBA/2J mice. Our results suggest that selegiline can partially preserve the hearing in certain forms of ARHL by alleviating its development. It might also be otoprotective in other mammals or humans.

Mid-term evaluation of perioperative i.v. corticosteroid treatment efficacy on overall and audiological outcome following CO2 laser stapedotomy: a retrospective study of 84 cases

Purpose

Our aim was to determine whether perioperatively administered corticosteroid treatment has any beneficial effect on the outcome of stapes surgery, with special regard to the audiological results and early postoperative morbidity.

Methods

84 CO₂ laser stapedotomies performed in our institute between 2013 and 2018 were included in our investigation. All cases underwent preoperative and mid-term postoperative pure-tone audiometric evaluation. Vestibular complications were also evaluated. The cases were subdivided into two groups, 23 patients received perioperative i.v. methylprednisolone treatment (“S”) while the other 61 patients (“nS”) did not receive any adjuvant pharmacological therapy. The data were analyzed retrospectively using IBM SPSS Statistics.

Results

CO₂ laser stapedotomy proved to be a successful intervention with a significant improvement in ABG and AC thresholds as well. Long-term BC levels were significantly better compared to preoperative ones in the S group; however, in the nS group, no difference could be shown. Hearing and ABG gain were significantly superior in group S [28.1 dB (SD11.2) vs. 18.1 dB (SD 10.9) and 23.9 dB(SD 9.8) vs. 17.2 dB (SD 9.5), respectively].

Conclusion

No significant inner ear damage was detectable in the results of our CO₂ laser stapedotomy method; however, the positive effect of corticosteroid treatment could be demonstrated through the postoperative hearing levels. We found no statistical difference in early postoperative morbidity. According to our data, the routine administration of corticosteroids during stapes surgery could be an issue worthy of consideration. The effects of perioperative treatment vs that on the first day after surgery, and topical vs. systemic treatment could be the subject of further investigation in a prospective manner.

A new aspect of aminoglycoside ototoxicity: impairment of cochlear dopamine release

Aminoglycoside ototoxicity is a well-documented process via several pathophysiological pathways. The protective role of cochlear dopamine, released from the lateral olivocochlear efferents, was implicated previously in case of ischemia or acoustic trauma, as it postsynaptically inhibits the effect of excessively released glutamate from the hair cells. In our in vitro superfusion experiments we showed that neomycin dose- dependently inhibits the dopamine release from isolated guinea pig cochlea, while gentamicin and kanamycin was ineffective on it. After chronic application of neomycin the dopamine outflow did not change significantly, suggesting an adaptive process. In our experiments we have found a possibly new action site of one of the aminoglycoside antibiotics, neomycin.

Anti-PD-1 Therapy Does Not Influence Hearing Ability in the Most Sensitive Frequency Range, but Mitigates Outer Hair Cell Loss in the Basal Cochlear Region

The administration of immune checkpoint inhibitors (ICIs) often leads to immune-related adverse events. However, their effect on auditory function is largely unexplored. Thorough preclinical studies have not been published yet, only sporadic cases and pharmacovigilance reports suggest their significance. Here we investigated the effect of anti-PD-1 antibody treatment (4 weeks, intraperitoneally, 200 μg/mouse, 3 times/week) on hearing function and cochlear morphology in C57BL/6J mice. ICI treatment did not influence the hearing thresholds in click or tone burst stimuli at 4–32 kHz frequencies measured by auditory brainstem response. The number and morphology of spiral ganglion neurons were unaltered in all cochlear turns. The apical-middle turns (<32 kHz) showed preservation of the inner and outer hair cells (OHCs), whilst ICI treatment mitigated the age-related loss of OHCs in the basal turn (>32 kHz). The number of Iba1-positive macrophages has also increased moderately in this high frequency region. We conclude that a 4-week long ICI treatment does not affect functional and morphological integrity of the inner ear in the most relevant hearing range (4–32 kHz; apical-middle turns), but a noticeable preservation of OHCs and an increase in macrophage activity appeared in the >32 kHz basal part of the cochlea.

Comparative Study Between the Auditory and Vestibular Functions in Ménière's Disease

OBJECTIVES

To evaluate the relationship between the loss of the cochleovestibular functions in Ménière's disease (MD).

METHODS

Forty-three patients with definite MD underwent pure-tone audiometry (PTA) and caloric test. Canal paresis (CP%), dPTA (interaural difference), and average PTA results were contrasted. IBM SPSS V24 was used for statistical analysis.

RESULTS

According to PTA, most patients were in stage C, and caloric weakness was found in 29 patients. Linear (R ² = 0.06) and nonlinear correlation tests (rho = 0.245, P = .113) between canal paresis (CP%) and dPTA showed no correlation, as well as between CP% and PTA analysis (R ² = 0.007, rho = 0.11, P = .481). As per the categorial analysis, no correlation was detected between the groups either (κ = 0.174, 95% CI: 0.0883 - 0.431). Based on the results of the analysis, it was concluded that a more advanced stage determined by audiometry does not indicate increasing values in the CP% parameter.

CONCLUSIONS

Audiometric changes do not directly correspond with the vestibular ones; therefore, no specific correlation exists between them. Thus, for therapy planning and diagnosis, both tests are necessary.

[Etiological factors of sensorineural hearing loss in children after cochlear implantation]

Introduction: Congenital sensorineural hearing loss is one of the most common sensory defects affecting 1-3 children per 1000 newborns. There are a lot of causes which result in congenital hearing loss, the most common is the genetic origin, but infection, cochlear malformation or other acquired causes can be reasons as well. Aim: The aim of this study was to establish the etiological factors of congenital profound sensorineural hearing loss in children who underwent cochlear implantation. Results: Our results show that the origin of the hearing loss was discovered in 62.9% of our patients. The most common etiological factor was the c.35delG mutation of the gap junction protein β-2 gene, the allele frequency was 38.7% in our cohort. Infection constituted to 10.1%, and meningitis and cytomegalovirus infection were the second most common cause. 79.9% of our patients received sufficient hearing rehabilitation before the end of the speech development's period (6 years old), but 11.2% of our cases were still diagnosed late. Conclusions: Based on our data we can state that genetic evaluation is crucial in the diagnostic process of congenital profound sensorineural hearing loss. Sufficient hearing rehabilitation affects the whole life of the child, and by late cochlear implantation the speech development falls behind. We can decrease the ratio of the late implantation with the new protocol of newborn hearing screening, and with sufficient information provided to the colleagues, so the children may be referred to the proper center for rehabilitation without delay. Orv Hetil. 2019; 160(21): 822-828.

[Verification results of objective newborn hearing screening]

Sufficient hearing is the cornerstone of the development of children's complex sensory perception, sound recognition, speech development and optimal communication skills. Hearing screening of newborns is necessary to detect congenital hearing disorders. Compulsory objective hearing screening in Hungary is a significant improvement in early diagnosis. The Audiological Department of Otorhinolaryngology, Head and Neck Surgery Clinic at Semmelweis University serves as a verification center for children identified via the compulsory objective newborn hearing screening and necessitates more detailed assessment. The goal of this study was to summarize the verification results of the year 2018. Case history, ENT examination, electric response measurement, impedance tests, otoacoustic emission measurement, surdopedagogical examination, and genetic examination are the basics of the diagnosis and the therapy as well. Altogether 261 newborns were examined in 2018 and 164 were subjected to audiological tests during the analyzed seven-month period. Normal hearing was detected in both ears in 77% of the cases, while hearing loss has been verified in 37 patients (23% of cases). Permanent hearing loss has been diagnosed in 19 cases, 4 unilateral and 15 bilateral. Hearing loss of sensorineural origin was confirmed in 17, conductive in 2 children. Temporary hearing loss caused by otitis media with effusion was found in further 18 children which healed spontaneously in most cases. Organized neonatal objective hearing examination has been established in Hungary in 2015. As a result, we can diagnose and provide care for children with hearing loss at the earliest stage. The National Newborn Hearing Screening Registry ensures a well-coordinated and smooth process. Orv Hetil. 2019; 160(47): 1850-1855.

Changes in the cochlear and retrocochlear parts of the auditory system in 19-39 and 40-60 years old patients with type 1 diabetes mellitus

Pathophysiological alterations in the cochlea and functional tests of the auditory pathway support that in diabetes both vasculopathy and neural changes could be present. The aim of our research was to study the differential effect of type 1 diabetes mellitus (T1DM) on two different age groups. Audiological investigation was carried out in 42 patients and 25 controls at the same age groups. Investigation of the conductive and sensorineural part of the hearing system by pure tone audiometry, distortion product otoacoustic emission measurement and acoustically evoked brainstem response registration were evaluated. Among the 19-39-year-old people the incidence of hearing impairment was not different in the diabetes and control groups. Among the 40-60-year-old people hearing impairment was more common in the diabetes group (75%) than in the control group (15,4%). Among patients with type 1 diabetes, the mean threshold values were higher in both age groups at all frequencies although significant difference was in 19-39 years old group: 500-4000Hz right ear, 4000Hz left ear, in 40-60 years old group: 4000-8000 Hz both ears. In the 19-39 years old diabetes group only at 8000 Hertz on the left side was a significant (p<0,05) difference in otoacoustic emissions. In the 40-60 years old diabetes group significantly less otoacoustic emissions at 8000 Hz on the right side (p<0,01) and at 4000-6000-8000 Hertz on the left side, (p<0,05, p<0,01, p<0,05 respectively) was present compared to the control group. According to ABR (auditory brainstem response) latencies and wave morphologies, a possible retrocochlear lesion arose in 15% of the 19-39 years old and 25% of the 40-60 years old diabetes group. According to our results, T1DM affects negatively the cochlear function and the neural part of the hearing system. The alterations are more and more detectable with aging.

Prevention of noise-induced hearing loss in children - evidence-informed recommendations for safe listening at events

OBJECTIVE

Children's events are often perceived as excessively loud, with risks of noise-induced hearing loss and other adverse effects. In many countries, including Hungary, specific regulations for recreational noise levels are absent. This research aims to establish a scientific basis for safety categories and noise level limits to protect children's hearing.

DESIGN

Noise levels were measured at events, and otoacoustic emissions were assessed to determine auditory impacts. Children and parents also completed loudness perception surveys.

STUDY SAMPLE

Thirteen events were analysed with 25 noise-level measurement points. We included children aged 3-12 years, conducted 38 otoacoustic emission tests on both ears before and after the event, and collected 51 completed questionnaires.

RESULTS

Only seven measurement points were in the "safe" category, 40% were "risky", and 32% were "dangerous". While safe events did not alter inner ear function, it was reduced in several cases after risky events. High noise intensities were uncomfortable for 80% of the children.

CONCLUSIONS

Children's events often exceed safe noise levels, underscoring the critical need for sound monitoring and control. We recommend implementing guidelines, public education, and warnings to prevent hearing loss, with proposed regulations and age-related safety recommendations, presenting sound intensity categories with letters A to F.

[Recognition and complex diagnostics of functional hearing loss]

INTRODUCTION

Hearing loss is a sensory impairment that impairs speech understanding, communication and therefore the quality of life. Sometimes the patient's perceived loss of function is exaggerated; subjective and objective test results are inconsistent, the subjectively reported hearing loss is more significant, and in these cases functional hearing loss is considered.

OBJECTIVE

Our aim was to collect and retrospectively analyze cases with the diagnosis of functional hearing loss, in order to draw conclusions about the characteristics of functional hearing loss, the signs and conditions that may be of attention and the consideration of appropriate rehabilitation.

METHODS

Subjective tests were performed with pure-tone auditory threshold, speech understanding and communication tests, which were compared with the results obtained with objective impedance measurements, stapedial reflex tests, otoacoustic emission measurements, and brainstem evoked response recordings. Imaging studies, psychologist, psychiatrist, neurologist, neurologist and other co-specialists were involved as needed. We excluded cases of deception deliberately intended to obtain financial or other benefits.

RESULTS

Between 2007 and 2022, 19 patients were diagnosed with functional hearing loss. The majority (17 cases) were female, the complaints were prevalent at a young age (10-41 years); the average age in the study population was 19.6 years, and the majority of patients (13 cases) were children aged 10-17 years. No organic cause was found in 11 cases, and in the remaining cases no detectable organic abnormality explained the extent of the hearing loss experienced by the patient. The degree of functional hearing loss varied (35-120 dB), with an average of 60,2 dB.

CONCLUSION

Recognizing and diagnosing functional hearing loss is very difficult and requires a complex series of tests and professional cooperation. Without recognition, the patient may receive unjustified, even harmful and financially burdensome care, which may lead to the deterioration of his condition. Orv Hetil. 2023; 164(8): 283-292.

Korai posztoperatív ízérzészavar középfülsebészeti beavatkozásokat követően

Bevezetés: A modern középfülsebészeti beavatkozások egyik fontos célja a hallás javításán felül a posztoperatív életminőség optimalizálása is. A leggyakoribb posztoperatív szövődmények közé tartozik az átmeneti vagy végleges ízérzészavar, mely a chorda tympani anatómiai elhelyezkedéséből adódó sérülési kockázattal magyarázható. A fenti szövődmény jellemzőinek részeletes ismerete a betegek tájékoztatásához és a legjobb intraoperatív döntéshozatalhoz is megkerülhetetlen. Célkitűzés: A korai posztoperatív időszakban kialakuló ízérzészavarok vizsgálata. A különböző műtéti típusok, valamint a műtét során bekövetkezett chorda tympani manipulációnak az ízérzésváltozásra gyakorolt hatását kívántuk tisztázni. Módszerek: A pácienseket prospektív módon a beavatkozás előtt és annak másnapján kitöltött kérdőívek segítségével vizsgáltuk. 15 betegnél stapesműtét, 28 betegnél tympanoplastica történt. Vizuális analóg skála (VAS, 0–10) és egyszerű eldöntendő kérdések segítségével vizsgáltuk a változást. A manipulációkat 5 kategóriára osztottuk az ideget ért behatás mértéke alapján. Eredmények: A tympanoplasticákat és a stapesműtéteket összehasonlítva nem volt különbség a posztoperatív ízérzési panaszok között (VAS: 9 vs. 9,1; p = 0,861). A ’0’, ’1’ és ’2’ csoportban az átlagos VAS-érték 10, 9,26 és 8,5 volt. A „manipuláció nélküli” (0) és a „jelentős fokú manipuláció látható sérülés nélkül” (2) csoport között szignifikáns különbséget találtunk (VAS: 10 vs. 8,5; p = 0,039). A stapesműtétes csoportban ízérzésre vonatkozó jelentős szövődmény (VAS<5) nem jelentkezett. Megbeszélés: Megfelelő mikroszkópos fülsebészeti technika mellett relatíve alacsony szövődményszámot találtunk, a műtéti típus nem befolyásolta a vizsgált szövődményrátát. Következtetés: A posztoperatív ízérzészavar kialakulása alacsony szinten tartható, a chorda tympani megőrzése a legtöbbször lehetséges. A panaszok kialakulásának mértéke az idegmanipuláció mértékével összefüggést mutatott, a műtéti típussal viszont nem. Orv Hetil. 2022; 163(23): 920–925.

Revision Stapedotomies: the Role of Periprosthetic Scar Tissue Formation in the Development of Unsatisfactory Hearing Results after Stapedotomy

Introduction  Revision stapes surgeries are difficult to perform, and their audiological results are inferior to primary surgeries.

Objective  Our goal was to identify the most common and most influential postoperative reasons that cause persistent air-bone gap (ABG) after the primary surgery. Our focus was concentrated on the mechanical dysfunctions in the middle ear, with special regard to postoperative adhesion formation.

Methods  We performed a retrospective case series study with 23 cases that underwent revision stapedotomies.

Results  A significant improvement was seen in ABG and air conduction levels after surgery. The periprosthetic adhesion formation was seen in 65% of the cases, and it was the primary cause behind the unsatisfactory hearing result in 30% of cases. There was no significant difference in the level of persistent ABGs after the primary surgery, in case of the intratympanic adhesion presence, compared with the presence of other surgical failures. Concerning hearing and ABG gain after revision surgery, the non-inferiority of the negative effect associated with adhesion was shown compared with the other reasons.

Conclusion  The revision stapedotomy is an efficient treatment option in case of persistent ABG. Periprosthetic adhesions are the most common intratympanic reasons for compromised audiological outcomes after stapedotomy.

Adhesion formations have the same negative effect on ABG development as any other surgical failure, and the revision could be more challenging in these cases. These findings highlight the use of the most atraumatic surgical technique and preservation of intact intratympanic mucosa during middle ear surgery.

[Hearing rehabilitation in postmeningitis deafness in the context of the time factor]

INTRODUCTION

Postmeningitis deafness appears in 0-11% of the meningitis cases. Cochlear ossification can develop in these patients, which may make the hearing rehabilitation impossible with cochlear implantation. Due to ossification, it is critical to refer patients to the implant centre without any delay.

OBJECTIVE

The aim of this study was to examine the time factor between the appearance of deafness and the first examination in a cochlear implant centre, the possibilities and effectivity of hearing rehabilitation.

METHOD

In our tertial referral centre, postmeningitis deafened patients were examined between 2014 and 2022 retrospectively. Hearing results, imaging, possibilities of rehabilitation, complications of cochlear implantations and the hearing results were investigated.

RESULTS

8 patients (3 children, 5 adults) were investigated. The time between the start of deafness and the first appearance varied between 3 weeks to 9 years. Bilateral profound hearing loss was measured in all patients. In 6 cases, cochlear ossification was observed (4 patients bilateral). Cochlear implantation was conducted in 5 patients (4 bilateral, 1 unilateral). In 3 cases, implantation was impossible due to severe ossification. Hearing results showed good hearing levels with poor speech perception in all cases.

DISCUSSION

The rehabilitation of severe hearing loss caused by meningitis can present many challenges to clinicians. A critical point in the care is the urgent referral of patients to a cochlear implantation centre as soon as possible after the life-threatening condition has passed. The implementation of further diagnostic and the earliest possible implantation is the responsibility of the implantation centre itself.

CONCLUSION

It is recommended to develop a new protocol with the involvement of allied professions to clear patient pathways for an effective treatment strategy. Orv Hetil. 2023; 164(19): 729-738.

[ACOUSTIC CR®-NEUROMODULATION -- FIRST EXPERIENCIES IN HUNGARY WITH A NOVEL METHOD IN THE THERAPY OF CHRONIC SUBJECTIVE TINNITUS]

OBJECTIVE

Acoustic CR®-neuromodulation is a novel patented method for the therapy of chronic subjective tinnitus and has been tested in Hungary, as one of the first European countries introducing this procedure. It can be used for the treatment of monaural or binaural tonal tinnitus. Suitability of patients for this therapy was assessed by the help of an appropriate set of criteria. Aim of our study was to analyze 6-month therapy and related measurement data of patients first treated with this method in Hungary and evaluate the results.

METHOD

27 outpatients (20 males, seven females) with a minimum of 6-month long history of subjective tinnitus were assessed (four detected on the right side, six on the left side, 17 on both sides) who were treated for six months by Acoustic CR®-neuromodulation. On 44 treated ears (21 right, 23 left), changes of tinnitus frequency and loudness were measured and analysed, using Visual Analogue Scale (VAS) loudness/annoyance/pitch scores and Tinnitus Handicap Inventory tests, which were performed at defined intervals during the treatment period.

RESULTS

During this 6-month treatment period, significant decrease was detected in tinnitus frequency and loudness by tinnitometry (irrespective of the affected side), and an improvement in VAS annoyance/pitch scores and THI test results. VAS loudness did not show any significant changes.

CONCLUSION

Acoustic CR®-neuromodulation therapy may be a useful treatment of subjective chronic tinnitus, but its efficacy should be proved in controlled clinical trials.

Audiological outcomes after revision stapes surgeries: a systematic review

PURPOSE

Revision stapes surgery is a challenging procedure performed in relatively small numbers compared to other middle ear procedures. Despite numerous data on hearing results of different middle ear surgeries, the audiological standards for successful outcome of this procedure are still not clarified. On the basis of well-documented data, we wanted to determine what the expected audiological results and complications are after revision stapes surgery in order to set a realistic threshold for surgical success.

METHODS

After the protocol registration in the PROSPERO database, a systematic review was performed in multiple databases (PubMed, Cochrane, Web of Science, Scopus, ScienceOpen, ClinicalTrials.gov, Google Scholar) according to PRISMA guidelines. Twelve articles were reviewed according to the inclusion criteria. A total of 1032 cases were obtained for evaluation. A modified version of Newcastle-Ottawa Scale (NOS) was used to assess publication quality.

RESULTS

Average air-bone gap (ABG) gain was 17.3 dB, average air conduction (AC) gain was 17.5 dB. The average postoperative air-bone gap was 11.1 dB. The postoperative ABG distribution was the following 0-10 dB: 53.3%, > 10-20 dB: 28.2%, > 20 dB: 18.5%. SNHL as a surgical complication was described in a total of 17 cases (1.6%), no equilibrium disorder was reported.

CONCLUSION

The pooled data suggest that revision stapes surgery is an effective solution after failure of previous stapes surgery. However, the results are clearly inferior to those of primary stapedotomies. Hence, we need to apply different expectations and use different standards in the indication and evaluation of this type of surgery.