Transcriptional response to mild therapeutic hypothermia in noise-induced cochlear injury.

Introduction: Prevention or treatment for acoustic injury has been met with many translational challenges, resulting in the absence of FDA-approved interventions. Localized hypothermia following noise exposure mitigates acute cochlear injury and may serve as a potential avenue for therapeutic approaches. However, the mechanisms by which hypothermia results in therapeutic improvements are poorly understood.

Targeted therapeutic hypothermia protects against noise induced hearing loss.

Introduction: Exposure to occupational or recreational loud noise activates multiple biological regulatory circuits and damages the cochlea, causing permanent changes in hearing sensitivity. Currently, no effective clinical therapy is available for the treatment or mitigation of noise-induced hearing loss (NIHL). Here, we describe an application of localized and non-invasive therapeutic hypothermia and targeted temperature management of the inner ear to prevent NIHL.

A reliable and reproducible protocol for sound-evoked vestibular myogenic potentials in rattus norvegicus.

Introduction: Cervical vestibular evoked myogenic potentials (cVEMPs) provide an objective measure of the integrity of the sacculo-collic pathway leading to their widespread use as a clinical tool in the diagnostic vestibular test battery. Though the application of cVEMPs in preclinical models to assess vestibular function, as performed in relevant clinical populations, remains limited. The present study aimed to establish a rodent model of cVEMP with standardized methods and protocols, examine the neural basis of the responses, and characterize and validate important features for interpretation and assessment of vestibular function.

Prevalence of Hearing Loss and Perceptions of Hearing Health and Protection among Florida Firefighters.

Firefighters are exposed to extensive hazardous noise while on the job, both during routine tasks at the station and when responding to calls. However, little is known about firefighters' occupational noise hazards. This study employed mixed methods, including focus groups, a survey, and audiometric testing, to identify sources of noise in the firefighters' work environment, determine hearing protective strategies, discern firefighters' perceptions of occupational noise exposure and impacts to their health, and quantify the prevalence of hearing loss among South Florida firefighters.

Monitoring Occupational Noise Exposure in Firefighters Using the Apple Watch.

Occupational noise exposure and hearing loss are prominent in the fire service. Firefighters are routinely exposed to hazardous levels of noise arising from the tools and equipment they use, from sirens and alarm tones to the emergency response vehicles they drive. The present study utilized the Apple Watch to continuously measure environmental noise levels for on-duty firefighters.

Mitochondrial responses to intracellular Ca release following infrared stimulation.

Many studies of Ca effects on mitochondrial respiration in intact cells have used electrical and/or chemical stimulation to elevate intracellular [Ca], and have reported increases in [NADH] and increased ADP/ATP ratios as dominant controllers of respiration. This study tested a different form of stimulation: brief temperature increases produced by pulses of infrared light (IR, 1,863 nm, 8-10°C for ∼5 s). Fluorescence imaging techniques applied to single PC-12 cells in low µM extracellular [Ca] revealed IR stimulation-induced increases in both cytosolic (fluo5F) and mitochondrial (rhod2) [Ca].

The effects of hearing protection devices on spatial awareness in complex listening environments.

Hearing protection devices (HPDs) remain the first line of defense against hazardous noise exposure and noise-induced hearing loss (NIHL). Despite the increased awareness of NIHL as a major occupational health hazard, implementation of effective hearing protection interventions remains challenging in at-risk occupational groups including those in public safety that provide fire, emergency medical, or law enforcement services. A reduction of situational awareness has been reported as a primary barrier to including HPDs as routine personal protective equipment.

Mild therapeutic hypothermia protects against inflammatory and proapoptotic processes in the rat model of cochlear implant trauma.

Objective: Mild therapeutic hypothermia (MTH) has been demonstrated to prevent residual hearing loss from surgical trauma associated with cochlear implant (CI) insertion. Here, we aimed to characterize the mechanisms of MTH-induced hearing preservation in CI in a well-established preclinical rodent model.

Approach: Rats were divided into four experimental conditions: MTH-treated and implanted cochleae, cochleae implanted under normothermic conditions, MTH only cochleae and un-operated cochleae (controls).

Subclinical Hearing Deficits in Noise-Exposed Firefighters.

Noise-induced hearing loss (NIHL) is the most prevalent occupational disease in the world and firefighters are at increased risk of NIHL due to their frequent exposure to hazardous levels of noise during service. Adverse effects of NIHL include acceleration of age-related hearing loss and an increased risk of cognitive decline. A critical challenge in addressing NIHL is the delayed clinical presentation of symptoms and lack of sensitive tools for early detection.

Risk-taking propensity as a risk factor for noise-induced hearing loss in the general population.

Objectives: To examine general risk propensity in relation to perceptions of noise, risk behaviour, and hearing loss in the general population.

Design: Participants completed an online survey using the Amazon Mechanical Turk crowdsourcing platform.

Study Sample: The sample comprised 1274 adults from the United States.

Pulsed Infrared Stimulation of Vertical Semicircular Canals Evokes Cardiovascular Changes in the Rat.

A variety of stimuli activating vestibular end organs, including sinusoidal galvanic vestibular stimulation, whole body rotation and tilt, and head flexion have been shown to evoke significant changes in blood pressure (BP) and heart rate (HR). While a role for the vertical semicircular canals in altering autonomic activity has been hypothesized, studies to-date attribute the evoked BP and HR responses to the otolith organs. The present study determined whether unilateral activation of the posterior (PC) or anterior (AC) semicircular canal is sufficient to elicit changes in BP and/or HR.

I-Corps@NCATS trains clinical and translational science teams to accelerate translation of research innovations into practice.

Introduction: A key barrier to translation of biomedical research discoveries is a lack of understanding among scientists regarding the complexity and process of implementation. To address this challenge, the National Science Foundation's Innovation Corps™ (I-Corps™) program trains researchers in entrepreneurship. We report results from the implementation of an I-Corps™ training program aimed at biomedical scientists from institutions funded by the National Center for Advancing Translational Sciences (NCATS).

Additive Protective Effects of Delayed Mild Therapeutic Hypothermia and Antioxidants on PC12 Cells Exposed to Oxidative Stress.

Mild therapeutic hypothermia is protective against several cellular stresses, but the mechanisms underlying this protection are not completely resolved. In the present study, we used an model to investigate whether therapeutic hypothermia at 33°C applied following a peroxide-induced oxidative stress would protect PC12 cells. A 1-hour exposure to tert-butyl peroxide increased cell death measured 24 hours later.

Therapeutic hypothermia reduces cortical inflammation associated with utah array implants.

Objective: Neuroprosthetics hold tremendous promise to restore function through brain-computer interfaced devices. However, clinical applications of implantable microelectrodes remain limited given the challenges of maintaining neuronal signals for extended periods of time and with multiple biological mechanisms negatively affecting electrode performance. Acute and chronic inflammation, oxidative stress, and blood brain barrier disruption contribute to inconsistent electrode performance.

Anatomical Correlates and Surgical Considerations for Localized Therapeutic Hypothermia Application in Cochlear Implantation Surgery.

Hypothesis: Application of localized, mild therapeutic hypothermia during cochlear implantation (CI) surgery is feasible for residual hearing preservation.

Background: CI surgery often results in a loss of residual hearing. In preclinical studies, local application of controlled, mild therapeutic hypothermia has shown promising results as a hearing preservation strategy.

Neuroinflammation, oxidative stress, and blood-brain barrier (BBB) disruption in acute Utah electrode array implants and the effect of deferoxamine as an iron chelator on acute foreign body response.

The use of intracortical microelectrode arrays has gained significant attention in being able to help restore function in paralysis patients and study the brain in various neurological disorders. Electrode implantation in the cortex causes vasculature or blood-brain barrier (BBB) disruption and thus elicits a foreign body response (FBR) that results in chronic inflammation and may lead to poor electrode performance. In this study, a comprehensive insight into the acute molecular mechanisms occurring at the Utah electrode array-tissue interface is provided to understand the oxidative stress, neuroinflammation, and neurovascular unit (astrocytes, pericytes, and endothelial cells) disruption that occurs following microelectrode implantation.

Eye Movements Evoked by Pulsed Infrared Radiation of the Rat Vestibular System.

Light at infrared wavelengths has been demonstrated to modulate the pattern of neural signals transmitted from the angular motion sensing semicircular canals of the vestibular system to the brain. In the present study, we have characterized physiological eye movements evoked by focused, pulsed infrared radiation (IR) stimuli directed at an individual semicircular canal in a mammalian model. Pulsed IR (1863 nm) trains were directed at the posterior semicircular canal in a rat using 200-400 µm optical fibers.

Pulsed infrared releases Ca from the endoplasmic reticulum of cultured spiral ganglion neurons.

Inner ear spiral ganglion neurons were cultured from day 4 postnatal mice and loaded with a fluorescent Ca indicator (fluo-4, -5F, or -5N). Pulses of infrared radiation (IR; 1,863 nm, 200 µs, 200-250 Hz for 2-5 s, delivered via an optical fiber) produced a rapid, transient temperature increase of 6-12°C (above a baseline of 24-30°C). These IR pulse trains evoked transient increases in both nuclear and cytosolic Ca concentration ([Ca]) of 0.

Blood brain barrier (BBB)-disruption in intracortical silicon microelectrode implants.

Chronically implanted microelectrodes in the neural tissue elicit inflammatory responses that are time varying and have been shown to depend on multiple factors. Among these factors, blood brain barrier (BBB)-disruption has been hypothesized as one of the dominant factors resulting in electrode failure. A series of events that includes BBB and cell-membrane disruption occurs during electrode implantation that triggers multiple biochemical cascades responsible for microglial and astroglial activation, hemorrhage, edema, and release of pro-inflammatory neurotoxic cytokines that causes neuronal degeneration and dysfunction.

Theoretical Evaluation and Experimental Validation of Localized Therapeutic Hypothermia Application to Preserve Residual Hearing After Cochlear Implantation.

Objectives: Cochlear implantation surgery has been shown to result in trauma to inner ear sensory structures, resulting in loss of residual hearing. Localized therapeutic hypothermia has been shown in clinical care to be a neuroprotective intervention. Previously, we have shown in an experimental model that localized hypothermia protects cochlear hair cells and residual hearing function against surgical and cochlear implantation trauma.

Effectiveness in Rehabilitation of Current Wireless CROS Technology in Experienced Bone-Anchored Implant Users.

Objective: To compare the effectiveness of current contralateral routing of signal technology (CROS) to bone-anchored implants in experienced bone-anchored implant users with unilateral severe-profound sensorineural hearing loss.

Design: Prospective, within-subject repeated-measures comparison study.

Setting: Tertiary referral center.

Neural Crest Stem Cells Can Differentiate to a Cardiomyogenic Lineage with an Ability to Contract in Response to Pulsed Infrared Stimulation.

Introduction: Cellular cardiomyoplasty has rapidly risen to prominence in the clinic following a myocardial infarction; however, low engraftment of transplanted cells limits the therapeutic benefit to these procedures. Recently, lineage-specific stem cells differentiated into cardiomyocytes have gained much attention to assist in the repair of an injured heart tissue; however, questions regarding the ideal cell source remain. In the present study, we have identified a source that is easy to extract stem cells from and show that the cells present have a high plasticity toward the cardiomyogenic lineage.

Comparison of Speech-in-Noise and Localization Benefits in Unilateral Hearing Loss Subjects Using Contralateral Routing of Signal Hearing Aids or Bone-Anchored Implants.

Objective: To compare the benefit of wireless contralateral routing of signal (CROS) technology to bone-anchored implant (BAI) technology in monaural listeners.

Study Design: Prospective, single-subject.

Setting: Tertiary academic referral center.

A cool approach to reducing electrode-induced trauma: Localized therapeutic hypothermia conserves residual hearing in cochlear implantation.

Objective: The trauma caused during cochlear implant insertion can lead to cell death and a loss of residual hair cells in the cochlea. Various therapeutic approaches have been studied to prevent cochlear implant-induced residual hearing loss with limited success. In the present study, we show the efficacy of mild to moderate therapeutic hypothermia of 4 to 6 °C applied to the cochlea in reducing residual hearing loss associated with the electrode insertion trauma.

Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling.

Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement.