Low-cost blast wave generator for studies of hearing loss and brain injury: Blast wave effects in closed spaces

Abstract

Background Military personnel and civilians living in areas of armed conflict have increased risk of exposure to blast overpressures that can cause significant hearing loss and/or brain injury. The equipment used to simulate comparable blast overpressures in animal models within laboratory settings is typically very large and prohibitively expensive. New Method To overcome the fiscal and space limitations introduced by previously reported blast wave generators, we developed a compact, low-cost blast wave generator to investigate the effects of blast exposures on the auditory system and brain. Results The blast wave generator was constructed largely from off the shelf components, and reliably produced blasts with peak sound pressures of up to 198 dB SPL (159.3 kPa) that were qualitatively similar to those produced from muzzle blasts or explosions. Exposure of adult rats to 3 blasts of 188 dB peak SPL (50.4 kPa) resulted in significant loss of cochlear hair cells, reduced outer hair cell function and a decrease in neurogenesis in the hippocampus. Comparison to existing methods Existing blast wave generators are typically large, expensive, and are not commercially available. The blast wave generator reported here provides a low-cost method of generating blast waves in a typical laboratory setting. Conclusions This compact blast wave generator provides scientists with a low cost device for investigating the biological mechanisms involved in blast wave injury to the rodent cochlea and brain that may model many of the damaging effects sustained by military personnel and civilians exposed to intense blasts.

Presbycusis Disrupts Spontaneous Activity Revealed by Resting-State Functional MRI

“…The increase in PTA thresholds are likely due to peripheral hearing loss and cochlear pathologies; however these change may contribute to central auditory disturbance that can contribute to presbycusis (Willott et al, 1993 ; Vasama and Mäkelä, 1997 ; Kraus et al, 2010 ; Newman et al, 2015 ). Impairments in peripheral hearing and central auditory processing have been linked to accelerated cognitive decline, incident cognitive impairment and AD (Gates and Mills, 2005 ; Panza et al, 2015 ).…”

Blast-Associated Shock Waves Result in Increased Brain Vascular Leakage and Elevated ROS Levels in a Rat Model of Traumatic Brain Injury

“…Compression-driven shock tube designs are also known to create longer pressure durations which are often not observed in realistic scenarios. Detonation-driven shock tube designs are usually associated with large overhead expenses, facilities and safety concerns which involve storage and use of explosives, thus often unsuitable to be utilized in a laboratory setting or for animal studies [ 21 , 34 ]. The shock tube design in the present study has been developed and optimized to assess the outcomes of blast exposures on rats.…”

Long-Term Functional and Structural Consequences of Primary Blast Overpressure to the Eye

“…1A,B) described in detail elsewhere. 17 Briefly, prior to blast exposure, rats were anesthetized (intramuscular [IM] injection) with a mixture of ketamine (75 mg/kg) and xylazine (15 mg/kg), and topical anesthetic (proparacaine hydrocholoride, 0.5% ophthalmic solution, Akorn, Inc.; 1-2 drops/eye) was instilled into each eye. Rats were then exposed to a single acoustic blast, with a sound pressure level of approximately 190 dB SPL (sound pressure *63 kilopascals [kPa]), using an 80-psi backpressure load of compressed nitrogen in the shock tube.…”

“…To determine the longitudinal progression of visual dysfunction after blast exposure, we used a relatively novel rat model of closedglobe ABO injury to the eye, employing a modified shock tube device originally developed by Newman and colleagues 17 to study blast injury to the auditory system. We characterized the changes in visual function and retinal structure in both the ipsilateral (proximal to the shock wave) and contralateral eyes, as well as changes in cognitive function and exploratory behavior following ABO exposure, in comparison with rats that had not been exposed to ABO.…”