Mechanisms and Mitigation of Hearing Loss from Blast Injury

Studies have been performed aimed at an improved biomechanical understanding of blast injury with the goal of creating new technologies for the mitigation of auditory injury from blast. Fiber-optic pressure sensors were used to measure and correlate external auditory canal (EAC) and intracranial pressure profiles during blast events. A compact programmable bench top simulator system was used to recreate recorded blast pressure profiles and deliver simulated blast wave forms at high intensity to human temporal bones. Intra-cochlear pressures were measured during harmonic and impulse stimuli using off-the-shelf fiber-optic pressure probes. Intra-cochlear pressures and ossicular displacements were recorded simultaneously and compared with those predicted by an existing auditory injury model. Stapedial displacements as measured both by scanning and single axis LDV were found to exceed predicted values for extremely high pressure sand long durations characteristic of blast events. An electromechanical transducer was used to counteract ossicular movement resulting from harmonic and impulse stimuli, demonstrating feasibility of active mitigation of auditory injury from blast exposure. Future activities will be directed to improved auditory hazard models and development of active systems protective against blast injury. The original document contains color images.