Exposure to Intense Noise Causes Vestibular Loss

• Published in: Military medicine Vol. 185; no. Supplement_1; pp. 454 - 461
• Main Authors: Stewart, Courtney E, Kanicki, Ariane C, Bauer, David S, Altschuler, Richard A, King, W Michael
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 07.01.2020
• Subjects: Animals; Bilateral Vestibulopathy - etiology; Bilateral Vestibulopathy - pathology; Disease Models, Animal; Environmental Exposure - adverse effects; Evoked Potentials, Auditory - physiology; Evoked Potentials, Auditory, Brain Stem; Hearing protection; Noise; Noise - adverse effects; Rats, Inbred LEC - injuries; Supplement
• ISSN: 0026-4075; 1930-613X; 1930-613X
• DOI: 10.1093/milmed/usz206

ABSTRACT Introduction The vestibular system is essential for normal postural control and balance. Because of their proximity to the cochlea, the otolith organs are vulnerable to noise. We previously showed that head jerks that evoke vestibular nerve activity were no longer capable of inducing a response after noise overstimulation. The present study adds a greater range of jerk intensities to determine if the response was abolished or required more intense stimulation (threshold shift). Materials and Methods Vestibular short-latency evoked potential (VsEP) measurements were taken before noise exposure and compared to repeated measurements taken at specific time points for 28 days after noise exposure. Calretinin was used to identify changes in calyx-only afferents in the sacculus. Results Results showed that more intense jerk stimuli could generate a VsEP, although it was severely attenuated relative to prenoise values. When the VsEP was evaluated 4 weeks after noise exposure, partial recovery was observed. Conclusion These data suggest that noise overstimulation, such as can occur in the military, could introduce an increased risk of imbalance that should be evaluated before returning a subject to situations that require normal agility and motion. Moreover, although there is recovery with time, some dysfunction persists for extended periods.