Optogenetic stimulation of the cochlear nucleus using channelrhodopsin-2 evokes activity in the central auditory pathways

Optogenetics has become an important research tool and is being considered as the basis for several neural prostheses. However, few studies have applied optogenetics to the auditory brainstem. This study explored whether optical activation of the cochlear nucleus (CN) elicited responses in neurons in higher centers of the auditory pathway and whether it elicited an evoked response. Viral-mediated gene transfer was used to express channelrhodopsin-2 (ChR2) in the mouse CN. Blue light was delivered via an optical fiber placed near the surface of the infected CN and recordings were made in higher-level centers. Optical stimulation evoked excitatory multiunit spiking activity throughout the tonotopic axis of the central nucleus of the inferior colliculus (IC) and the auditory cortex (Actx). The pattern and magnitude of IC activity elicited by optical stimulation was comparable to that obtained with a 50 dB SPL acoustic click. This broad pattern of activity was consistent with histological confirmation of green fluorescent protein (GFP) label of cell bodies and axons throughout the CN. Increasing pulse rates up to 320 Hz did not significantly affect threshold or bandwidth of the IC responses, but rates higher than 50 Hz resulted in desynchronized activity. Optical stimulation also evoked an auditory brainstem response, which had a simpler waveform than the response to acoustic stimulation. Control cases showed no responses to optical stimulation. These data suggest that optogenetic control of central auditory neurons is feasible, but opsins with faster channel kinetics may be necessary to convey information at rates typical of many auditory signals

Review Essay: Andy Clark, Natural-Born Cyborgs: Minds, Technologies, and the Future of Human Intelligence.

Review Essay: Andy Clark, Natural-Born Cyborgs: Minds, Technologies, and the Future of Human Intelligence

Optoacoustically induced auditory brainstem responses in the mouse model enhanced through an absorbing film

Significance: Optoacoustic stimulation offers an alternative stimulation strategy for the hearing organ. To serve as the base for a novel auditory prosthesis, the optoacoustic stimulation must be biocompatible and energy-saving. Aim: Enhancing the efficiency of optoacoustic stimulation while reducing the energy input in a suited animal model. Approach: Optoacoustically induced auditory brainstem responses (oABRs) were recorded after the pulsed laser irradiation of the tympanic membrane (TM) in mice. The results were compared with the ABRs induced through acoustic click stimulation. In addition, self-adhesive absorbing films were applied on the TM before the optoacoustic stimulation to investigate their effect on the resulting ABRs. Results: Using an absorbing film on the TM during optical stimulation led to considerably enhanced oABR wave I amplitude values compared with the stimulation of the bare TM. When using our stimulation strategy, we induced oABR waves in the 50% to 60% range of the acoustical stimulation reached with 80-dB SPL click stimuli. Conclusions: The mouse model can be used for certain developmental work for an optoacoustic auditory prosthesis. Using absorbing films on the TM during optical stimulation considerably enhances oABR wave I amplitude. Optimization of the stimulation strategy could further enhance the efficiency within biocompatibility margins

Auditory system rehabilitation - available technologies

In this article some of the different technologies and its functioning as well as some technological aids for people with partial or total auditory deficiency will be presented. The objective of the auditory rehabilitation is to develop the capacity of auditory perception to the individual carrying auditory deficiency, with aid of devices that can amplify the sound. Between these devices, we cite: the Baha auditory prostheses, vibrant sound-bridge, the cochlear implantations, the auditory brainstem implants, the hearing prosthesis, the bone conduction prostheses and the intra-channels hearing. Some technological aiding devices not used in the ear are also presented such as the signal amplifier to phone, amplifier magnetic field to TV, sign language translator, phone with handset and light bell for home

Communication Deficiencies from Chimp to Child

Equating speech with language is a fallacy, declare these authors. They describe a plastic word non-speech response approach that opens a whole new vista for teaching the language-deficient child to communicate

Особенности неблагоприятных эффектов слухопротезирования

Department of Otorhinolaryngology, State University of Medicine and Pharmacy „Nicolae Testemitanu”, Chisinau, Republic of MoldovaWe distinguished the increased efficiency of prosthesis in cases of correct subjective and objective diagnosis of senzorineural hearing loss in determining the appropriate regime to adapt to hearing aids. We studied the disadvantages of prosthesis, evaluating tinnitus, headaches, irritability, rapid fatigue, and vertigo. Particularly, the instances of tinnitus, headache, and vertigo decreased significantly. In the study we developed a method to forecast the occurrence of nuisance auditory prosthesis, which can to increase the effectiveness of auditory prosthesis. The summary of the method lies in the selection of the decisive factors of forecasting the occurrence of nuisance auditory prosthesis in patients suffering from hearing loss. This conclusion is based on historical data and audiometric investigations, such as the patient’s age, the trigger, the evolution of hearing loss, the hearing threshold, and the articulation index.Увеличение эффективности слухопротезирования состоит как в субъективной и объективной диагностике тугоухости, так и в определении соответствующих мер для адаптации к слуховому аппарату. Мы провели исследование осложнений слухопротезирования таких как: шум в ушах, головная боль, раздражительность, быстрая утомляемость, головокружения. Было установлено, что преобладающие субъективные ощущения в начале слухопротезирования уменьшались во время дальнейшего использования слуховых аппаратов. В частности, значительно сократилось количество шума в ушах, головная боль, раздражительность, головокружения. В рамках исследования был разработан метод прогнозирования осложнений слухопротезирования, который предлагает увеличение эффективности электроакустической коррекции слуха. Сущность метода состоит в выборе решающих факторов возникновения осложнений слухопротезирования на основе анамнестических и аудиометрических данных: возраст пациента, этиологические факторы, эволюция тугоухости, слуховой порог и артикуляционный индекс

Aging: loss of hearing sensitivity of the elderly (presbycusis)

Aging, consensually assumed as a process that affects and alters significantly the cognitive and behavioral functions of the human being encompassing multiple effects on a number of clinically significant variables , the most important being those that directly relate to the movement, ability to balance the effectiveness of mental functioning and sensory functions such as taste, smell, sight and hearing. Hearing loss in the elderly, scientifically called presbiacusis arises quietly and is increased progressively with advancing age. This study had as its aim to contribute to the best quality of life for elderly individuals with hearing loss (presbycusis). Thus, the objectives targeted were: trying to understand the motivations of the elderly to the use of hearing aids; determine the degree of satisfaction of users of these prostheses; evaluate how Preabycusis affects the quality of life of the elderly. The method used was qualitative oriented once interviewed the elderly users of the home. The sample was composed of 30 participants, with presbycusis, 25 female and 5 male (institutionalized seniors) from the city of Braga/Portugal. The instrument used was the semi-structured interview and through informal procedures and in a climate of dialogue facilitator and promoter of a simple and open speech.info:eu-repo/semantics/publishedVersio

Simulating Speech Perception in Bilateral Cochlear Implant Users with Asymmetric Input

Understanding speech in noise is difficult for cochlear-implant (CI) users. One potential reason for this difficulty is asymmetrical hearing between the two ears; that is, when one ear can process sound more effectively and clearly than the other ear. Such asymmetry may impair some CI users’ ability to fuse speech signals from both ears into a single stream. One way to test this is with an alternating speech paradigm, which is an experimental simplification of speech moving from talker to talker in a rapid conversation between a group of people. Previous studies have shown CI users perform 40% worse on alternating speech listening than normal-hearing individuals. The present study aims to examine if reduced alternating speech perception is the result of asymmetrical hearing, which could cause a listener to only use their better ear when listening to alternating speech, and to miss out on much of the signal that is present in the poorer ear. Six young normal-hearing participants were tested using a CI simulation with varying levels of signal degradation to simulate both asymmetrical and symmetrical hearing. The hypothesis was that participants will show selective attention to the ear with the clearer, less degraded signal in asymmetrical hearing conditions, and will overall perform worse in this condition compared to the symmetrical hearing condition. The results comparing the “better ear” and the asymmetric condition suggest that there is no evidence of selective attention; therefore we can reject the hypothesis. Future directions include increasing asymmetry across ears by simulating more drastic degradation in the “poorer ear”. Speech perception in noise is one of the most common issues CI users face, and quantifying the contributions of asymmetrical hearing to this problem is important for resolving this issue.Maryland Summer Scholars Progra

Distal Renal Tubular Acidosis and Sensorineural Deafness with Mutation in the ATP6V1B1 Gene

A acidose tubular renal distal é uma doença rara, caracterizada pela incapacidade na acidificação da urina, condicionando acidose metabólica hiperclorémica, hipocaliémia, hipercalciúria e nefrocalcinose, o que poderá causar atraso de crescimento, alteração do metabolismo ósseo e insuficiência renal crónica. A acidose tubular renal distal associada a surdez neurossensorial é uma doença de herança autossómica recessiva, causada por mutações do gene que codifica a subunidade B1 da H+ -ATPase (ATP6V1B1). Os autores relatam os casos de duas irmãs que apresentaram má progressão ponderal, alterações iónicas, do equilíbrio ácido base e surdez neurossensorial. Foi detectada em ambas as crianças a mutação homozigótica no gene ATP6V1B1. Com estes dois casos pretende -se destacar a importância de um diagnóstico precoce nesta patologia rara