Intracochlear pressure measurements during acoustic shock wave exposure

Greene, Nathaniel T.; Alhussaini, Mohamed A.; Easter, J.R.; Argo, Theodore F.; Walilko, Tim; Tollin, Daniel J.

doi:10.1016/j.heares.2018.05.014

Cited by 23 publications

(14 citation statements)

References 48 publications

(101 reference statements)

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“…A blast tube apparatus was used that has been described previously. [17][18][19] The air-driven shock tube (Applied Research Associates, Littleton, CO) was a 17-inch inner diameter tube with a 24-inch driver, an 8-foot long driven section, and a 4-foot expansion cone with a 7.5-degree angle of expansion. The diameter at the opening is *36 inches.…”

Section: Blast Injury Modelmentioning

confidence: 99%

A Mouse Model of Repetitive Blast Traumatic Brain Injury Reveals Post-Trauma Seizures and Increased Neuronal Excitability

Bugay¹,

Bozdemir²,

Vigil³

et al. 2020

Journal of Neurotrauma

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Repetitive blast traumatic brain injury (TBI) affects numerous soldiers on the battlefield. Mild TBI has been shown to have long-lasting effects with repeated injury. We have investigated effects on neuronal excitability after repetitive, mild TBI in a mouse model of blast-induced brain injury. We exposed mice to mild blast trauma of an average peak overpressure of 14.6 psi, repeated across three consecutive days. While a single exposure did not reveal trauma as indicated by the glial fibrillary acidic protein indicator, three repetitive blasts did show significant increases. As well, mice had an increased indicator of inflammation (Iba-1) and increased tau, tau phosphorylation, and altered cytokine levels in the spleen. Videoelectroencephalographic monitoring 48 h after the final blast exposure demonstrated seizures in 50% (12/24) of the mice, most of which were non-convulsive seizures. Long-term monitoring revealed that spontaneous seizures developed in at least 46% (6/13) of the mice. Patch clamp recording of dentate gyrus hippocampus neurons 48 h post-blast TBI demonstrated a shortened latency to the first spike and hyperpolarization of action potential threshold. We also found that evoked excitatory postsynaptic current amplitudes were significantly increased. These findings indicate that mild, repetitive blast exposures cause increases in neuronal excitability and seizures and eventual epilepsy development in some animals. The non-convulsive nature of the seizures suggests that subclinical seizures may occur in individuals experiencing even mild blast events, if repeated.

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Section: Blast Injury Modelmentioning

confidence: 99%

A Mouse Model of Repetitive Blast Traumatic Brain Injury Reveals Post-Trauma Seizures and Increased Neuronal Excitability

Bugay¹,

Bozdemir²,

Vigil³

et al. 2020

Journal of Neurotrauma

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“…These observations suggest that blast shock waves impact the vestibular end organs via the middle ear sound transduction pathway. Although the blast shock waves were delivered primarily into the ear canal and few damage was observed in the untreated ear, a role of bone transduction cannot be ruled out ( Greene et al., 2018 ). In addition to blast-induced structural damage to the middle ear, we also confirmed stereocilia bundle damage to the vestibular hair cells.…”

Section: Resultsmentioning

confidence: 99%

Exposure to blast shock waves via the ear canal induces deficits in vestibular afferent function in rats

Huang

Tang

et al. 2020

Journal of Otology

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The ears are air-filled structures that are directly impacted during blast exposure. In addition to hearing loss and tinnitus, blast victims often complain of vertigo, dizziness and unsteady posture, suggesting that blast exposure induces damage to the vestibular end organs in the inner ear. However, the underlying mechanisms remain to be elucidated. In this report, single vestibular afferent activity and the vestibulo-ocular reflex (VOR) were investigated before and after exposure to blast shock waves (∼20 PSI) delivered into the left external ear canals of anesthetized rats. Single vestibular afferent activity was recorded from the superior branch of the left vestibular nerves of the blast-treated and control rats one day after blast exposure. Blast exposure reduced the spontaneous discharge rates of the otolith and canal afferents. Blast exposure also reduced the sensitivity of irregular canal afferents to sinusoidal head rotation at 0.5–2Hz. Blast exposure, however, resulted in few changes in the VOR responses to sinusoidal head rotation and translation. To the best of our knowledge, this is the first study that reports blast exposure-induced damage to vestibular afferents in an animal model. These results provide insights that may be helpful in developing biomarkers for early diagnosis of blast-induced vestibular deficits in military and civilian populations.

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“…Similar measurements in living patients are difficult and ethically concerning. We have utilized comparable methods to provide quantitative estimates of resulting noise exposure from blast exposure, cochlear implant insertion, drill use, and laser use 9,10,14,28 . Our results reveal that P IC is significantly elevated during laser application and that pressures increase with increasing laser power.…”

Section: Discussionmentioning

confidence: 97%

“…Prior to insertion of the pressure sensors (FOP‐M260‐ENCAP; FISO Inc), baseline measurements of the stapes and round window were obtained with laser Doppler vibrometry (LDV) to ensure that specimens were representative of normal, healthy, living ears. These steps have been described in detail in prior reports 10‐15 . Cochleostomies were created under a droplet of water with a fine pick.…”

Section: Methodsmentioning

confidence: 99%

Effects of Varying Laser Parameters During Laser Stapedotomy on Intracochlear Pressures

Boscoe

Hartl

Gubbels

et al. 2022

Otolaryngol.--head neck surg.

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Objective Sensorineural hearing loss is a known complication of stapes surgery. We previously showed that laser stapedotomy can result in intracochlear pressures that are comparable to high sound pressure levels. Optimizing laser settings to those that correspond with the lowest pressure changes may mitigate risk for postoperative hearing loss. Here we quantify the effects of various laser parameters on intracochlear pressures and test the hypothesis that intracochlear pressure changes are proportional to the laser energy delivered. Study Design Basic and translational science. Setting Cadaveric dissection and basic science laboratory. Methods Cadaveric human heads underwent mastoidectomies. Intracochlear pressures were measured via fiber-optic pressure probes placed in scala vestibuli and tympani. Pulses of varied stimulus power and duration from a 980-nm diode laser were applied to the stapes footplate. Results Sustained high-intensity pressures were observed in the cochlea during all laser applications. Observed pressure magnitudes increased monotonically with laser energy and rose linearly for lower stimulus durations and powers, but there was increased variability for laser applications of longer duration (200-300 ms) and/or higher power (8 W). Conclusions Results confirm that significant pressure changes occur during laser stapedotomy, which we hypothesize may cause injury. Overall energy delivered depends predictably on duration and power, but surgeons should use caution at the highest stimulus levels and longest pulse durations due to the increasing variability in intracochlear pressure under these stimulus conditions. While the risk to hearing from increased intracochlear pressures from laser stapedotomy remains unclear, these results affirm the need to optimize laser settings to avoid unintended injury.

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Intracochlear pressure measurements during acoustic shock wave exposure

Cited by 23 publications

References 48 publications

A Mouse Model of Repetitive Blast Traumatic Brain Injury Reveals Post-Trauma Seizures and Increased Neuronal Excitability

A Mouse Model of Repetitive Blast Traumatic Brain Injury Reveals Post-Trauma Seizures and Increased Neuronal Excitability

Exposure to blast shock waves via the ear canal induces deficits in vestibular afferent function in rats

Effects of Varying Laser Parameters During Laser Stapedotomy on Intracochlear Pressures

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