scholarly journals Magnetic Stimulation Allows Focal Activation of the Mouse Cochlea

2022 ◽  
Author(s):  
Jae-Ik Lee ◽  
Richard Seist ◽  
Stephen McInturff ◽  
Daniel J Lee ◽  
Christian Brown ◽  
...  
Keyword(s):  
Neural Coding ◽  
Magnetic Stimulation ◽  
Dynamic Range ◽  
Functional Performance ◽  
Electrode Array ◽  
Acoustic Stimulation ◽  
Profound Hearing Loss ◽  
Safety Testing ◽  
Spectral Channels ◽  
Additional Safety

Cochlear implants (CIs) strive to restore hearing to those with severe to profound hearing loss by artificially stimulating the auditory nerve. While most CI users can understand speech in a quiet environment, hearing that utilizes complex neural coding (e.g., appreciating music) has proved elusive, probably because of the inability of CIs to create narrow regions of spectral activation. Several novel approaches have recently shown promise for improving spatial selectivity, but substantial design differences from conventional CIs will necessitate much additional safety testing before clinical viability is established. Outside the cochlea, magnetic stimulation from small coils (micro-coils) has been shown to confine activation more narrowly than that from conventional micro-electrodes, raising the possibility that coil-based stimulation of the cochlea could improve the spectral resolution of CIs. To explore this, we delivered magnetic stimulation from micro-coils to multiple locations of the cochlea and measured the spread of activation utilizing a multi-electrode array inserted into the inferior colliculus; responses to magnetic stimulation were compared to analogous experiments with conventional micro-electrodes as well as to the responses to auditory monotones. Encouragingly, the extent of activation with micro-coils was ~60% narrower than that from electric stimulation and largely similar to the spread arising from acoustic stimulation. The dynamic range of coils was more than three times larger than that of electrodes, further supporting a smaller spread of activation. While much additional testing is required, these results support the notion that coil-based CIs can produce a larger number of independent spectral channels and may therefore improve functional performance. Further, because coil-based devices are structurally similar to existing CIs, fewer impediments to clinical translational are likely to arise.

Implantable hearing interfaces

2018 ◽  
Author(s):  
Torsten Lehmann ◽  
André van Schaik
Keyword(s):  
Cochlear Implants ◽  
Neural Activity ◽  
Dynamic Range ◽  
Systems Design ◽  
Fundamental Operation ◽  
Profound Hearing Loss ◽  
Biomedical Implant ◽  
Dynamic Range Compression ◽  
Hearing Function ◽  
Key Aspects

The chapter Implantable hearing interfaces describes the fundamental operation of a commonly available biohybrid system, the cochlear implant, or bionic ear. This neuro-stimulating biomedical implant is very successful in restoring hearing function to people with profound hearing loss. The fundamental operation of the biological cochlea is described and parallels are drawn between key aspects of the biological system and the biohybrid implementation: dynamic range compression, translation of sound to neural activity, and tonotopic mapping. Critical considerations are discussed for simultaneously meeting biological, surgical, and engineering restrictions in successful biohybrid systems design. Finally, challenges in present and future cochlear implants are outlined and directions of current research given.

scholarly journals Investigation of intracochlear dual actuator stimulation in a scaled test rig

2017 ◽  
Vol 3 (2) ◽  
pp. 119-122
Author(s):  
Wouter J. van Drunen ◽  
Sarra Kacha Lachheb ◽  
Anatoly Glukhovskoy ◽  
Jens Twiefel ◽  
Marc C. Wurz ◽  
...  
Keyword(s):  
Low Frequency ◽  
Acoustic Stimulation ◽  
Residual Hearing ◽  
Frequency Range ◽  
Test Rig ◽  
Profound Hearing Loss ◽  
Ongoing Research ◽  
Electric Acoustic Stimulation ◽  
Single Implant

AbstractFor patients suffering from profound hearing loss or deafness still having respectable residual hearing in the low frequency range, the combination of a hearing aid with a cochlear implant results in the best quality of hearing perception (EAS – electric acoustic stimulation). In order to optimize EAS, ongoing research focusses on the integration of these stimuli in a single implant device. Within this study, the performance of piezoelectric actuators, particularly the dual actuator stimulation, in a scaled uncoiled test rig was investigated.

scholarly journals Development of surface reconstruction algorithms for optical interferometric measurement

2020 ◽  
Author(s):  
Dongxu Wu ◽  
Fengzhou Fang
Keyword(s):  
Surface Topography ◽  
Dynamic Range ◽  
Functional Performance ◽  
Theoretical Background ◽  
Optical Interferometry ◽  
Reconstruction Algorithms ◽  
Fringe Analysis ◽  
Intelligent Sampling ◽  
On Line ◽  
Accuracy And Repeatability

AbstractOptical interferometry is a powerful tool for measuring and characterizing areal surface topography in precision manufacturing. A variety of instruments based on optical interferometry have been developed to meet the measurement needs in various applications, but the existing techniques are simply not enough to meet the ever-increasing requirements in terms of accuracy, speed, robustness, and dynamic range, especially in on-line or on-machine conditions. This paper provides an in-depth perspective of surface topography reconstruction for optical interferometric measurements. Principles, configurations, and applications of typical optical interferometers with different capabilities and limitations are presented. Theoretical background and recent advances of fringe analysis algorithms, including coherence peak sensing and phase-shifting algorithm, are summarized. The new developments in measurement accuracy and repeatability, noise resistance, self-calibration ability, and computational efficiency are discussed. This paper also presents the new challenges that optical interferometry techniques are facing in surface topography measurement. To address these challenges, advanced techniques in image stitching, on-machine measurement, intelligent sampling, parallel computing, and deep learning are explored to improve the functional performance of optical interferometry in future manufacturing metrology.

scholarly journals Neural activity related to volitional regulation of cortical excitability

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Kathy Ruddy ◽  
Joshua Balsters ◽  
Dante Mantini ◽  
Quanying Liu ◽  
Pegah Kassraian-Fard ◽  
...  
Keyword(s):  
Magnetic Stimulation ◽  
Dynamic Range ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Recovery Of Function ◽  
Brain State ◽  
Large Dynamic Range ◽  
Conditioning Paradigm ◽  
Alpha Oscillations ◽  
Human Motor

To date there exists no reliable method to non-invasively upregulate or downregulate the state of the resting human motor system over a large dynamic range. Here we show that an operant conditioning paradigm which provides neurofeedback of the size of motor evoked potentials (MEPs) in response to transcranial magnetic stimulation (TMS), enables participants to self-modulate their own brain state. Following training, participants were able to robustly increase (by 83.8%) and decrease (by 30.6%) their MEP amplitudes. This volitional up-versus down-regulation of corticomotor excitability caused an increase of late-cortical disinhibition (LCD), a TMS derived read-out of presynaptic GABAB disinhibition, which was accompanied by an increase of gamma and a decrease of alpha oscillations in the trained hemisphere. This approach paves the way for future investigations into how altered brain state influences motor neurophysiology and recovery of function in a neurorehabilitation context.

Pump Up the Volume: Could Excessive Neural Gain Explain Tinnitus and Hyperacusis?

2015 ◽  
Vol 20 (4) ◽  
pp. 273-282 ◽  
Author(s):  
Hannah Brotherton ◽  
Christopher J. Plack ◽  
Michael Maslin ◽  
Roland Schaette ◽  
Kevin J. Munro
Keyword(s):  
Auditory System ◽  
Dynamic Range ◽  
Sensory Deprivation ◽  
Acoustic Stimulation ◽  
Neural Firing ◽  
Slow Adaptation ◽  
Health And Disease ◽  
Adaptation Processes ◽  
Perceptual Changes ◽  
Neural Gain

Naturally occurring stimuli can vary over several orders of magnitude and may exceed the dynamic range of sensory neurons. As a result, sensory systems adapt their sensitivity by changing their responsiveness or ‘gain'. While many peripheral adaptation processes are rapid, slow adaptation processes have been observed in response to sensory deprivation or elevated stimulation. This adaptation process alters neural gain in order to adjust the basic operating point of sensory processing. In the auditory system, abnormally high neural gain may result in higher spontaneous and/or stimulus-evoked neural firing rates, and this may have the unintended consequence of presenting as tinnitus and/or sound intolerance, respectively. Therefore, a better understanding of neural gain, in health and disease, may lead to more effective treatments for these aberrant auditory perceptions. This review provides a concise summary of (i) evidence for changes in neural gain in the auditory system of animals, (ii) physiological and perceptual changes in adult human listeners following an acute period of enhanced acoustic stimulation and/or deprivation, (iii) physiological evidence of excessive neural gain in tinnitus and hyperacusis patients, and (iv) the relevance of neural gain in the clinical treatment of tinnitus and hyperacusis.

Application of electric-acoustic stimulation in patients with profound hearing loss—case study

2003 ◽  
Vol 1240 ◽  
pp. 291-295
Author(s):  
H Skarżyński ◽  
A Piotrowska ◽  
A Lorens ◽  
J Szuchnik ◽  
A Walkowiak ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Acoustic Stimulation ◽  
Profound Hearing Loss ◽  
Electric Acoustic Stimulation

scholarly journals The Benefits of Using RONDO and an In-the-Ear Hearing Aid in Patients Using a Combined Electric-Acoustic System

2015 ◽  
Vol 2015 ◽  
pp. 1-4 ◽  
Author(s):  
Dayse Távora-Vieira ◽  
Stuart Miller
Keyword(s):  
Single Unit ◽  
Hearing Aid ◽  
Control Unit ◽  
Acoustic Stimulation ◽  
Profound Hearing Loss ◽  
Low Frequencies ◽  
Speech Processor ◽  
High Frequencies ◽  
Acoustic Hearing ◽  
Electric Acoustic Stimulation

People with residual hearing in the low frequencies and profound hearing loss in the high frequencies often do not benefit from acoustic amplification. Focus on this group of patients led to the development of the combined electric-acoustic stimulation (EAS) systems which can provide users with greater speech perception than can cochlear implant (CI) alone or acoustic hearing alone. EAS users wear a combined speech processor that incorporates a behind-the-ear audio processor that sits with an ear hook on the user’s pinna and a hearing aid, which sits in the ear canal. However, with the introduction of single-unit processors, which combine the audio processor, coil, control unit, and battery pack into a single device that sits on the implant site, therefore off the ear, simultaneous electric (CI) and acoustic (hearing aid) stimulation is not currently possible with a combined processor. To achieve EAS with a single-unit processor, a CI user must also wear a hearing aid. This study seeks to determine if experienced users of combined EAS speech processors could also benefit from using a combination of a single-unit speech processor that sits off the ear and an in-the-ear hearing aid.

Analysis of Interspike Interval of Dorsal Horn Neurons Evoked by Different Needle Manipulations at St36

2014 ◽  
Vol 32 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Tao Zhou ◽  
Jiang Wang ◽  
Chun-Xiao Han ◽  
Ishida Torao ◽  
Yi Guo
Keyword(s):  
Firing Rate ◽  
Dorsal Horn ◽  
Neural Coding ◽  
Spinal Dorsal Horn ◽  
Interspike Interval ◽  
Dynamic Range ◽  
Stimulus Frequency ◽  
Electrical Signals ◽  
Spinal Dorsal ◽  
Wdr Neurons

Objectives Previous research has suggested that different manual acupuncture (MA) manipulations may have different physiological effects. Recent studies have demonstrated that neural electrical signals are generated or changed when acupuncture is administered. In order to explore the effects of different MA manipulations on the neural system, an experiment was designed to record the discharges of wide dynamic range (WDR) neurons in the spinal dorsal horn evoked by MA at different frequencies (0.5, 1, 2 and 3 Hz) at ST36. Methods Microelectrode extracellular recordings were used to record the discharges of WDR neurons evoked by different MA manipulations. Approximate firing rate and coefficient of variation of interspike interval (ISI) were used to extract the characteristic parameters of the neural electrical signals after spike sorting, and the neural coding of the evoked discharges by different MA manipulations was obtained. Results Our results indicated that the neuronal firing rate and time sequences of ISI showed distinct clustering properties for different MA manipulations, which could distinguish them effectively. Conclusions The combination of firing rate and ISI codes carries information about the acupuncture stimulus frequency. Different MA manipulations appear to change the neural coding of electrical signals in the spinal dorsal horn through WDR neurons.

Impact of Electric Stimulation on Residual Hearing

2015 ◽  
Vol 26 (08) ◽  
pp. 732-740 ◽  
Author(s):  
Margaret T. Dillon ◽  
Andrea L. Bucker ◽  
Marcia C. Adunka ◽  
English R. King ◽  
Oliver F. Adunka ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Electric Stimulation ◽  
Bone Conduction ◽  
Low Frequency ◽  
Electrode Array ◽  
Hearing Preservation ◽  
Acoustic Stimulation ◽  
First Year ◽  
Residual Hearing ◽  
Listening Experience

Background: Candidacy criteria for cochlear implantation are expanding to include patients with substantial low-to-mid frequency hearing sensitivity. Postoperative hearing preservation has been achieved in cochlear implant recipients, though with variable outcomes. Previous investigations on postoperative hearing preservation outcomes have evaluated intraoperative procedures. There has been limited review as to whether electric stimulation influences hearing preservation. Purpose: The purpose of this analysis was to evaluate whether charge levels associated with electric stimulation influence postoperative hearing preservation within the first year of listening experience. Research Design: Retrospective analysis of unaided residual hearing and charge levels. Study Sample: Twenty-eight cochlear implant recipients with postoperative residual hearing in the operative ear and at least 12 mo of listening experience with electric-acoustic stimulation (EAS). Data Collection and Analysis: Assessment intervals included initial cochlear implant activation, initial EAS activation, and 3-, 6-, and 12-mo postinitial EAS activation. A masked low-frequency bone-conduction (BC) pure-tone average (PTA) was calculated for all participants at each assessment interval. Charge levels for each electrode were determined using the most comfortable loudness level and pulse width values. Charge levels associated with different regions of the electrode array were compared to the change in the low-frequency BC PTA between two consecutive intervals. Results: Charge levels had little to no association with the postoperative change in low-frequency BC PTA within the first year of listening experience. Conclusions: Electric charge levels do not appear to be reliably related to the subsequent loss of residual low-frequency hearing in the implanted ear within the first year of EAS listening experience.

scholarly journals Improved alpha-beta power reduction via combined Electrical and Ultrasonic stimulation in a Parkinsonian Cortex-Basal Ganglia-Thalamus Computational Model

2021 ◽  
Author(s):  
Thomas Tarnaud ◽  
Wout Joseph ◽  
Ruben Schoeters ◽  
Luc Martens ◽  
Emmeric Tanghe
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Basal Ganglia ◽  
Neuronal Network ◽  
Continuous Wave ◽  
Dynamic Range ◽  
Cortical Cell ◽  
Acoustic Stimulation ◽  
Isolated Neurons ◽  
Beta Power

AbstractObjectiveTo investigate computationally the interaction of combined electrical and ultrasonic modulation of isolated neurons and of the Parkinsonian cortex-basal ganglia-thalamus loop.MethodsContinuous-wave or pulsed electrical and ultrasonic neuromodulation is applied to isolated Otsuka plateau-potential generating subthalamic nucleus (STN) and Pospischil regular, fast and low-threshold spiking cortical cells in a temporally-alternating or simultaneous manner. Similar combinations of electrical/ultrasonic waveforms are applied to a Parkinsonian biophysical cortex-basal ganglia-thalamus neuronal network. Ultrasound-neuron interaction is modelled respectively for isolated neurons and the neuronal network with the NICE and SONIC implementations of the bilayer sonophore underlying mechanism. Reduction in α—β spectral energy is used as a proxy to express improvement in Parkinson’s disease by insonication and electrostimulation.ResultsSimultaneous electro-acoustic stimulation achieves a given level of neuronal activity at lower intensities compared to the separate stimulation modalities. Conversely, temporally alternating stimulation with 50 Hz electrical and ultrasound pulses is capable of eliciting 100 Hz STN firing rates. Furthermore, combination of ultrasound with hyperpolarizing currents can alter cortical cell relative spiking regimes. In the Parkinsonian neuronal network, high-frequency pulsed separated electrical and ultrasonic deep brain stimulation (DBS) reduce pathological α — β power by entraining STN-neurons. In contrast, continuous-wave ultrasound reduces pathological oscillations by silencing the STN. Compared to the separated stimulation modalities, temporally simultaneous or alternating electro-acoustic stimulation can achieve higher reductions in α — β power for the same contraints on electrical/ultrasonic intensity.ConclusionContinuous-wave and pulsed ultrasound reduce pathological oscillations by different mechanisms. Electroacoustic stimulation further improves α— β power for given safety limits and is capable of altering cortical relative spiking regimes.Significancefocused ultrasound has the potential of becoming a non-invasive alternative of conventional DBS for the treatment of Parkinson’s disease. Here, we elaborate on proposed benefits of combined electro-acoustic stimulation in terms of improved dynamic range, efficiency, resolution, and neuronal selectivity.

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