Input compensation of dolphin and sea lion auditory brainstem responses using frequency-modulated up-chirps.

Frequency-modulated "chirp" stimuli that offset cochlear dispersion (i.e., input compensation) have shown promise for increasing auditory brainstem response (ABR) amplitudes relative to traditional sound stimuli.

Output compensation of auditory brainstem responses in dolphins and sea lions.

Cochlear dispersion causes increasing delays between neural responses from high-frequency regions in the cochlear base and lower-frequency regions toward the apex. For broadband stimuli, this can lead to neural responses that are out-of-phase, decreasing the amplitude of farfield neural response measurements. In the present study, cochlear traveling-wave speed and effects of dispersion on farfield auditory brainstem responses (ABRs) were investigated by first deriving narrowband ABRs in bottlenose dolphins and California sea lions using the high-pass subtractive masking technique.

The offset auditory brainstem response in bottlenose dolphins (Tursiops truncatus): Evidence for multiple underlying processes.

The auditory brainstem response (ABR) to stimulus onset has been extensively used to investigate dolphin hearing. The mechanisms underlying this onset response have been thoroughly studied in mammals. In contrast, the ABR evoked by sound offset has received relatively little attention.

Analytical Evaluation of Signal-to-Noise Ratios for Avalanche- and Single-Photon Avalanche Diodes.

Performance of systems for optical detection depends on the choice of the right detector for the right application. Designers of optical systems for ranging applications can choose from a variety of highly sensitive photodetectors, of which the two most prominent ones are linear mode avalanche photodiodes (LM-APDs or APDs) and Geiger-mode APDs or single-photon avalanche diodes (SPADs). Both achieve high responsivity and fast optical response, while maintaining low noise characteristics, which is crucial in low-light applications such as fluorescence lifetime measurements or high intensity measurements, for example, Light Detection and Ranging (LiDAR), in outdoor scenarios.

Role of the temporal window in dolphin auditory brainstem response onset.

Auditory brainstem responses (ABRs) to linear-enveloped, broadband noisebursts were measured in six bottlenose dolphins to examine relationships between sound onset envelope properties and the ABR peak amplitude. Two stimulus manipulations were utilized: (1) stimulus onset envelope pressure rate-of-change was held constant while plateau pressure and risetime were varied and (2) plateau duration was varied while plateau pressure and risetime were held constant. When the stimulus onset envelope pressure rate-of-change was held constant, ABR amplitudes increased with risetime and were fit well with an exponential growth model.

Offset auditory brainstem response (ABR) amplitude in bottlenose dolphins.

Although commonly recorded as onset responses, the auditory brainstem response (ABR) can also be elicited at stimulus offset. The offset ABR has not been extensively investigated in marine mammals. Three normal hearing (NH) and three hearing impaired (HI) dolphins were assessed while fully submerged in sea water.

A novel intracochlear injection method for rapid drug delivery to vestibular end organs.

Background: Injection into the inner ear through the round window (RW) or a cochleostomy is a reliable method for delivering drugs or viruses to the cochlea. This method has been less effective for fast deliveries to vestibular end organs.

New Method: We describe a novel approach for rapid delivery of drugs to the vestibular end organ via the oval window (OW) and scala vestibuli in 1-3 month old C57BL/6 mice.

Auditory brainstem responses during aerial testing with bottlenose dolphins (Tursiops truncatus): Effects of electrode and jawphone locations.

Transmission of sound to dolphins during electrophysiological hearing screening is conducted out of water in certain cases (e.g., strandings).

Clinical Practice Guideline: Ménière's Disease Executive Summary.

Objective: Ménière's disease (MD) is a clinical condition defined by spontaneous vertigo attacks (each lasting 20 minutes to 12 hours) with documented low- to midfrequency sensorineural hearing loss in the affected ear before, during, or after one of the episodes of vertigo. It also presents with fluctuating aural symptoms (hearing loss, tinnitus, or ear fullness) in the affected ear. The underlying etiology of MD is not completely clear, yet it has been associated with inner ear fluid volume increases, culminating in episodic ear symptoms (vertigo, fluctuating hearing loss, tinnitus, and aural fullness).

Clinical Practice Guideline: Ménière's Disease.

Objective: Ménière's disease (MD) is a clinical condition defined by spontaneous vertigo attacks (each lasting 20 minutes to 12 hours) with documented low- to midfrequency sensorineural hearing loss in the affected ear before, during, or after one of the episodes of vertigo. It also presents with fluctuating aural symptoms (hearing loss, tinnitus, or ear fullness) in the affected ear. The underlying etiology of MD is not completely clear, yet it has been associated with inner ear fluid (endolymph) volume increases, culminating in episodic ear symptoms (vertigo, fluctuating hearing loss, tinnitus, and aural fullness).

Using Unidirectional Rotations to Improve Vestibular System Asymmetry in Patients with Vestibular Dysfunction.

The vestibular system provides information about head movement and mediates reflexes that contribute to balance control and gaze stabilization during daily activities. Vestibular sensors are located in the inner ear on both sides of the head and project to the vestibular nuclei in the brainstem. Vestibular dysfunction is often due to an asymmetry between input from the two sides.

Firefighter protective clothing and self contained breathing apparatus does not alter balance testing using a standard sensory organization test or motor control test in healthy, rested individuals.

Background: There is a high rate of injury associated with firefighting: in 2016, 21% of all fireground injuries were attributed to falls, jumps and slips. Examining factors related to balance, including experience in wearing firefighter gear, may assist in reducing injury related to falls.

Objectives: To assess the effects of wearing firefighter gear on postural balance in firefighters and non-firefighters in a rested condition.

Effects of stimulus cosine onset properties on bottlenose dolphin (Tursiops truncatus) auditory brainstem responses.

Although the auditory brainstem response (ABR) is known to be an onset response, the specific relationship between stimulus onset properties and the resulting ABR is not well understood. In this study, the effects of stimulus onset on dolphin ABR were examined by measuring ABRs in six bottlenose dolphins while systematically manipulating rise time and plateau sound pressure of cosine-enveloped noise bursts. Noise bursts were spectrally "pink" with frequency content from 10 to 160 kHz, rise times from 32 μs to 4 ms, and plateau sound pressure levels from 102 to 138 dB re 1 μPa.

The Effect of Recording Montage and Tone Burst Duration on Cervical and Ocular Vestibular Evoked Myogenic Potential Latency and Amplitude.

Objectives The objectives of this study were (a) to investigate the optimal tone burst duration when recording the cervical vestibular evoked myogenic potential (cVEMP) and the ocular vestibular evoked myogenic potential (oVEMP) and (b) to determine whether monopolar recording influences the latency or amplitude of the cVEMP or the oVEMP. Method Fifteen subjects ( M = 27.7 years, SD = 6.

Signal-to-noise ratio of auditory brainstem responses (ABRs) across click rate in the bottlenose dolphin (Tursiops truncatus).

Although the maximum length sequence (MLS) and iterative randomized stimulation and averaging (I-RSA) methods allow auditory brainstem response (ABR) measurements at high rates, it is not clear if high rates allow ABRs of a given quality to be measured in less time than conventional (CONV) averaging (i.e., fixed interstimulus intervals) at lower rates.

Stimulus bandwidth impact on auditory evoked potential thresholds and estimated upper-frequency limits of hearing in dolphins.

The frequency range of hearing is important for assessing the potential impact of anthropogenic noise on marine mammals. Auditory evoked potentials (AEPs) are commonly used to assess toothed whale hearing, but measurement methods vary across researchers and laboratories. In particular, estimates of the upper-frequency limit of hearing (UFL) can vary due to interactions between the unintended spread of spectral energy to frequencies below the desired test frequency and a sharp decline in hearing sensitivity at frequencies near the UFL.

Learning Effects and the Sensory Organization Test: Influence of a Unilateral Peripheral Vestibular Impairment.

Purpose: Healthy young controls exhibit a learning effect after undergoing repeated administrations of the sensory organization test (SOT). The primary objective of the present experiment was to determine if an SOT learning effect is present in individuals with a unilateral vestibular impairment (UVI), and if so, whether it is different from healthy controls. The secondary objective was to determine if the learning effect is dependent on the time frame of repeated SOT assessments.

Comparison of maximum length sequence and randomized stimulation and averaging methods on the bottlenose dolphin auditory brainstem response.

The purpose of the present study was to compare auditory brainstem responses (ABRs) using two approaches that allow the use of high stimulation rates, but with different temporal variability in the interstimulus interval: maximum length sequences (MLS) and iterative randomized stimulation and averaging (I-RSA). ABRs were obtained to click stimuli in six bottlenose dolphins (Tursiops truncatus). In experiment 1, click level was held constant and click rate varied from 25 to 1250 Hz.

The Influence of Caffeine on Rotary Chair and Oculomotor Testing.

Background: When patients are given instructions before vestibular function testing, they are often asked to refrain from ingesting caffeine 24 h before testing. However, research regarding the effects of caffeine on the outcome of vestibular function testing is limited.

Purpose: To evaluate whether the results from rotational chair tests are influenced by caffeine.

Effects of noise burst rise time and level on bottlenose dolphin (Tursiops truncatus) auditory brainstem responses.

Although the auditory brainstem response (ABR) is known to be an onset response, specific features of acoustic stimuli that affect the morphology of the ABR are not well understood. In this study, the effects of stimulus onset properties were investigated by measuring ABRs in seven bottlenose dolphins while systematically manipulating stimulus rise time and the amplitude of the sound pressure temporal envelope plateau. Stimuli consisted of spectrally pink (i.

Click reception in the harbor porpoise (Phocoena phocoena): Effects of electrode and contact transducer location on the auditory brainstem response.

Unlike terrestrial mammals that have unambiguous aerial sound transmission pathways via the outer ear and tympanum, sound reception pathways in most odontocetes are not well understood. Recent studies have used auditory brainstem response (ABR) measurements to examine sound reception pathways. This study sought to determine how sound source placements, recording electrode arrangements, and ABR peak analyses affect interpretations of sound reception in the harbor porpoise (Phocoena phocoena).

Vestibular evoked myogenic potential testing: Payment policy review for clinicians and payers.

Purpose Of Review: A recent American Academy of Neurology Evidence-Based Practice Guideline on vestibular myogenic evoked potential (VEMP) testing has described superior canal dehiscence syndrome (SCDS) and evaluated the merits of VEMP in its diagnosis. SCDS is an uncommon but now well-recognized cause of dizziness and auditory symptoms. This article familiarizes health care providers with this syndrome and the utility and shortcomings of VEMP as a diagnostic test and also explores payment policies for VEMP.