Effects of high intensity noise on the vestibular system in rats

Abstract

Some individuals with noise-induced hearing loss (NIHL) also report balance problems. These accompanying vestibular complaints are not well understood. The present study used a rat model to examine the effects of noise exposure on the vestibular system. Rats were exposed to continuous broadband white noise (0–24kHz) at an intensity of 116dB sound pressure level (SPL) via insert ear phones in one ear for three hours under isoflurane anesthesia. Seven days after the exposure, a significant increase in ABR threshold (43.3±1.9dB) was observed in the noise-exposed ears, indicating hearing loss. Effects of noise exposure on vestibular function were assessed by three approaches. First, fluorescein-conjugated phalloidin staining was used to assess vestibular stereocilia following noise exposure. This analysis revealed substantial sensory stereocilia bundle loss in the saccular and utricular maculae as well as in the anterior and horizontal semicircular canal cristae, but not in the posterior semicircular canal cristae. Second, single unit recording of vestibular afferent activity was performed under pentobarbital anesthesia. A total of 548 afferents were recorded from 10 noise-treated rats and 12 control rats. Noise exposure produced a moderate reduction in baseline firing rates of regular otolith afferents and anterior semicircular canal afferents. Also a moderate change was noted in the gain and phase of the horizontal and anterior semicircular canal afferent’s response to sinusoidal head rotation (1 and 2Hz, 45 degrees/s peak velocity). Third, noise exposure did not result in significant changes in gain or phase of the horizontal rotational and translational vestibular-ocular reflex (VOR). These results suggest that noise exposure not only causes hearing loss, but also causes substantial damage in the peripheral vestibular system in the absence of immediate clinically measurable vestibular signs. These peripheral deficits, however, may lead to vestibular disorders over time.

The Virtual Morris Water Task in 64 Patients With Bilateral Vestibulopathy and the Impact of Hearing Status

“…As the Morris Water Maze does not rely upon auditory function, authors hypothesize that the auditory input plays a maintenance role for hippocampal function and neurogenesis ( 37 ). However, it should be noted that exposing mice to noise trauma does not only result in hearing loss but might also induce peripheral vestibular damage ( 39 , 40 ). This has not been taken into account in the study.…”

Estradiol deficiency is a risk factor for idiopathic benign paroxysmal positional vertigo in postmenopausal female patients

“…The control group inclusion criteria were 1) postmenopausal women, 2) age of 50 to 80 years, and 3) no history of vertigo. The criteria for exclusion were noncooperation; presence of liver and kidney dysfunction; patients who had received vitamin D and calcium therapy or osteoporosis treatment; patients who were on hormone‐replacement therapy; and patients with posterior fossa tumor, a history of surgery or trauma of the head and/or neck, a particularly noisy living or working environment, high mental stress, a history of an ear disease (middle ear cholesteatoma, Meniere's disease) and migraine, and with an endocrine‐related disease.…”

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

“…Vestibular afferents activity was examined one day after blast exposure in the SD rats. Details of the surgeries were described previously ( Stewart et al., 2016 ; Zhu et al., 2011 , 2014 ). Briefly, a rat was anesthetized initially by injection of 50 mg/kg (i.p.)…”

“…Detailed data acquisition and analysis methods are described in earlier reports ( Stewart et al., 2016 ; Zhu et al., 2011 , 2014 ). Briefly, a CED Power 1401 system was used to sample single unit voltage signals at 20 kHz and head position signals at 1 kHz.…”