Stimulating auditory nerve with MEMS harvesters for fully implantable and self-powered cochlear implants

This paper presents a novel method for stimulating auditory nerve inside cochlea via a MEMS piezoelectric energy harvester (PEH) implanted on eardrum or ossicles 1 . In this method, the harvester composed of several cantilevers with varying resonance frequencies within the hearing band is utilized. The signals generated by each cantilever of the PEH are used to stimulate the corresponding section of the auditory nerve. The proposed method mimics the natural operation of cochlea, therefore eliminates the use of microphone, sound processor, battery, and transmitter that are currently used in conventional cochlear implants (CI's). In this framework, a single-cantilever MEMS PEH prototype is designed and fabricated. The prototype generates adequate signal to stimulate the auditory nerve at a typical eardrum vibration, proving the method's feasibility for the next generation fully implantable and self-powered CI's

Functional outcomes of Vibrant Soundbridge applied on the middle ear windows in comparison with conventional hearing aids

Conclusion: Vibrant Soundbridge (VSB) application to the middle ear windows yields better functional outcomes than conventional hearing aids. However, speech discrimination scores obtained with VSB and conventional hearing aids are similar. Objective: To assess audiological outcomes of round and oval window applications of VSB in comparison with conventional hearing aids. Methods: Nineteen adult patients were included in the study. The patients had mild to moderate, moderate or moderate to profound conductive or mixed hearing loss. During surgery the floating mass transducer (FMT) was placed on the round (n = 14) or oval (n = 5) window. After the surgery, audiometric evaluation and free field audiometric evaluation of both ears was carried out. Results: The hearing thresholds in the low frequencies were not significantly different between the conventional hearing aids and VSB. The functional gains obtained with oval and round window approaches were similar except for 500 Hz. The hearing thresholds in the mid and high frequencies were significantly better with VSB than the conventional hearing aids. The functional gain in the low frequencies was not significantly different between VSB and conventional hearing aids. The functional gain in the other frequencies was significantly better with VSB than conventional hearing aids

Expression of histamine receptors (H-1, H-2, and H-3) in the rabbit endolymphatic sac: an immunohistochemical study

WOS: 000251743600004PubMed: 18061827Objective: The endolymphatic sac (ES) is part of the membranous labyrinth of the inner ear. Its central role in immunologic activity within the inner ear has been confirmed by numerous studies. The aim of this study was to investigate the expression of histamine receptors (H-1, H-2, H-3) in the rabbit ES. Methods: A total of 10 healthy male New Zealand white rabbits weighing 2 to 3 kg were used in the experiments. For immunohistochemical studies, immunostaining was performed according to the avidin-biotin-peroxidase complex technique. Results: Serial sections of the ES of rabbits revealed the presence of H-1, H-2, and H-3 receptor immunoreactivity. Immunoreactive cells for all H-1, H-2, and H-3 were found in the epithelial and subepithelial layers of the duct and the proximal ES. In conclusion, this study showed the immunohistochemical localization of H-1, H-2, and H-3 receptors in the ES of rabbits. These receptors may be important in the homeostasis of the inner ear. In addition, they may be target receptors in the medical treatment of inner car disorders such as endolymphatic hydrops. (C) 2008 Published by Elsevier Inc

Visual and Postural Motion-Evoked Dizziness Symptoms Are Predominant in Vestibular Migraine Patients

Background. Vestibular migraine (VM) is one of the most common underdiagnosed disorders. We aimed to study the clinical characteristics of VM patients who were referred to a neurology-headache unit by otolaryngology after exclusion of peripheral causes of vertigo. Methods. One hundred and one patients diagnosed with VM in the headache unit were included. Description of vestibular symptoms, demographic and clinical features, trigger factors, accompanying diseases, and response to vestibular-suppressant medications and prophylactic migraine treatment were evaluated. Results. Vestibular symptoms were triggered by daily head and body movements and mainly consisted of brief attacks lasting seconds (60.4\% of patients) although the total duration of the vestibular episode lasted hours or days. Other aggravating factors were moving visual stimuli, passive motion, and visually busy environments. Visually induced vestibular symptoms were defined by 71.3\% of the patients, and positional motion-induced vestibular symptoms were described by 82.2\% of the patients. Vestibular symptoms were mainly defined as feeling the ground slipping from under their feet (40.6\%), feeling like there is an earthquake or swaying (27.7\%), sensation of rocking on a boat (26.7\%), and sensation as if stepping on empty space (24.8\%). The majority of the patients (83.2\%) previously used vestibular-suppressant drugs, and these drugs were effective temporarily only in 12.9\%. Conclusions. Chronic recurrent dizziness symptoms, rather than internal or external vertigo, are predominant in our VM patients. Recurrent brief dizziness attacks induced upon routine visual and/or postural motion, longstanding symptoms with limited response to vestibular suppressants, and precipitation by typical migraine triggers are suggestive of VM

Temporal bone paragangliomas: 15 years experience

Introduction: Temporal bone paragangliomas (TBPs) are benign tumors arising from neural crest cells located along the jugular bulbus and the tympanic plexus. In general surgical excision, radiotherapy and wait-and-scan protocols are the main management modalities for TBPs. Objective: In this paper we aim to present our clinical experience with TBPs and to review literature data. Methods: The patients who were operated for tympanomastoid paraganglioma (TMP) or tympanojugular paraganglioma (TJP) in our clinic in the last 15 years were enrolled in the study. A detailed patient's charts review was performed retrospectively. Results: There were 18 (52.9\%) cases with TMPs and 16 (47.1\%) cases with TJPs, a total of 34 patients operated for TBPs in this time period. The mean age was 50.3 11.7 (range 25-71 years). The most common presenting symptoms were tinnitus and hearing loss for both TMPs and TJPs. Gross total tumor resection was achieved in 17 (94.4\%) and 10 (62.5\%) cases for TMPs and TJPs, respectively. Five patients (31.2\%) with TJP experienced facial palsy following the operation. For all the patients the mean follow-up period was 25.8 months (range 4-108 months). Conclusion: In conclusion, based on our findings and literature review, total surgical excision alone or with preoperative embolization is the main treatment modality for TBPs. However radiotherapy, observation protocol and subtotal resection must be considered in cases of preoperative functioning cranial nerves, large tumors and advanced age. (C) 2016 Associacao Brasileira de Otorrinotaringologia e Cirurgia Cervico-Facial. Published by Elsevier Editora Ltda