Visual Vestibular Conflict Mitigation in Virtual Reality Using Galvanic Vestibular Stimulation.

Virtual reality (VR) is an effective technique to reduce cost and increase fidelity in training programs. In VR, visual and vestibular cues are often in conflict, which may result in simulator-induced motion sickness. The purpose of this study is to investigate the integration of Galvanic Vestibular Stimulation (GVS) with a VR flight training simulator by assessing flight performance, secondary task performance, simulator sickness and presence.

Generating Flight Illusions Using Galvanic Vestibular Stimulation in Virtual Reality Flight Simulations.

Background: Vestibular flight illusions remain a significant source of concern for aviation training. Most fixed-based simulation training environments, including new virtual reality (VR) technology, lack the ability to recreate vestibular flight illusions as vestibular cues cannot be provided without stimulating the vestibular end organs. Galvanic vestibular stimulation (GVS) has long been used to create vestibular perception.

Oculometric Feature Changes During Acute Hypoxia in a Simulated High-Altitude Airdrop Scenario.

Severe acute hypoxia results in a rapid deterioration of cognitive functioning and thus poses a risk for human operations in high altitude environments. This study aimed at investigating the effects of oxygen system failure during a high-altitude high-opening (HAHO) parachute jump scenario from 30,000 ft (9144 m) on human physiology and cognitive performance using a noncontact eye-tracking task. Nine healthy male volunteers (ages 27-48) were recruited from the Norwegian Special Operations Commandos.

Supplemental CO improves oxygen saturation, oxygen tension and cerebral oxygenation in acutely hypoxic healthy subjects.

Oxygen is viewed in medicine as the sole determinant of tissue oxygenation, though carbon dioxide homeostasis is equally important and clinically often ignored. The aims of this study were as follows: (a) to examine the effects of different acute hypoxic conditions on partial pressure of arterial oxygen ( ), arterial oxygen saturation of hemoglobin ( ), and regional cerebral saturation of hemoglobin (rSO ); and (b) to evaluate supplemental CO as a tool to improve oxygenation in acutely hypoxic individuals. We hypothesized that exposure to gas mixtures with added CO would improve oxygenation in hypoxic human subjects.

Discovering Oculometric Patterns to Detect Cognitive Performance Changes in Healthy Youth Football Athletes.

In this paper, we focus on the application of oculometric patterns extracted from raw eye movements during a mental workload task to assess changes in cognitive performance in healthy youth athletes over the course of a typical sport season. Oculometric features pertaining to fixations and saccades were measured on 116 athletes in pre- and post-season testing. Participants were between 7 and 14 years of age at pre-season testing.

Correlating Multi-dimensional Oculometrics with Cognitive Performance in Healthy Youth Athletes.

There is a need for a practical measure to detect mild changes in cognitive performance as early signs of concussion in youth or other special populations. In this paper, we propose a novel correlation model that establishes the relationship between oculometrics extracted from raw eye movements during a mental workload task and cognitive performance. We assessed differences in cognitive performance in terms of age for youth athletes based on oculometrics pertaining to fixations and saccades.

Labyrinthine concussion following gunshot injury: A case report.

Objective: Labyrinthine concussion due to a postauricular gunshot wound has not been well reported.

Design: Retrospective chart review.

Study Sample: We describe an otherwise healthy 22-year-old male who received a gunshot wound to the left mastoid and subsequently reported hearing loss and rotational vertigo.

Acute hypoxic hypoxia and isocapnic hypoxia effects on oculometric features.

Introduction: Visual performance impairment after hypoxia is well recognized in military and civilian aviation. The aims of this study were: 1) to assess oculometric features such as blink metrics, pupillary dynamics, fixations, and saccades as cognitive indicators of early signs of hypoxia; and 2) to analyze the impact of different hypoxic conditions ["hypoxic hypoxia" (HH) and "isocapnic hypoxia" (IH)] on specified oculometrics during mental workloads.

Methods: Oculometric data were collected on 25 subjects under 3 conditions: normoxia, HH (8% O2 + balance N2), and IH (7% O2 + 5% CO2 + balance N2).

Electrogastrographic and autonomic responses during oculovestibular recoupling in flight simulation.

Introduction: Simulator sickness causes vestibulo-autonomic responses that increase sympathetic activity and decrease parasympathetic activity. The purpose of the study was to quantify these responses through electrogastrography and cardiac interbeat intervals during flight simulation.

Methods: There were 29 subjects that were randomly assigned to 2 parallel arms: (1) oculovestibular recoupling, where galvanic vestibular stimulation was synchronous with the visual field; and (2) control.

Early detection of hypoxia-lnduced cognitive impairment using the King-Devick test.

Introduction: Hypoxic incapacitation continues to be a significant threat to safety and operations at high altitude. Noninvasive neurocognitive performance testing is desirable to identify presymptomatic cognitive impairment, affording operators at altitude a tool to quantify their performance and safety.

Methods: There were 25 subjects enrolled in this study.

Pure-tone hearing asymmetry: a logistic approach modeling age, sex, and noise exposure history.

Background: Asymmetric hearing loss (AHL) can be an early sign of vestibular schwannoma (VS). However, recognizing VS-induced AHL is challenging. There is no universally accepted definition of a "medically significant pure-tone hearing asymmetry," in part because AHL is a common feature of medically benign forms of hearing loss (e.

Oculo-vestibular recoupling using galvanic vestibular stimulation to mitigate simulator sickness.

Introduction: Despite improvement in the computational capabilities of visual displays in flight simulators, intersensory visual-vestibular conflict remains the leading cause of simulator sickness (SS). By using galvanic vestibular stimulation (GVS), the vestibular system can be synchronized with a moving visual field in order to lessen the mismatch of sensory inputs thought to result in SS.

Methods: A multisite electrode array was used to deliver combinations of GVS in 21 normal subjects.

The effect of galvanic vestibular stimulation on distortion product otoacoustic emissions.

Galvanic stimulation has long been used as a nonmechanical means of activating the vestibular apparatus through direct action on the vestibular nerve endings. This stimulation has been reported to be safe, but no studies have examined the potential changes in the corresponding cochlear receptors. The aim of the present study was to evaluate the effect of galvanic vestibular stimulation (GVS) on distortion product otoacoustic emissions (DPOAEs).

Negative effect of deep cochlear implant electrode insertion on speech perception.

This case study details the evaluation, explantation, and subsequent reimplantation of a cochlear implant (CI) recipient with an unusually deep electrode array insertion. Although the positive value of sufficiently deep insertion and the effect of insertion variability have been researched, there are few data available that illustrate the detrimental effects on speech recognition when deep insertion corrupts optimal use of the CI. This unique case report challenges the assumption that deeper insertion will result in improved speech understanding and demonstrates the importance of fully evaluating recipients' complaints and recognizing the impact of frequency-to-place mismatch.

Superficial siderosis of the central nervous system: phenotype and implications for audiology and otology.

Objective: Superficial siderosis of the central nervous system (SSCN) results after chronic subarachnoid hemorrhage. Consequent demyelination, particularly of the cochleovestibular nerve and cerebellum, causes auditory-vestibular dysfunction. Predominant symptoms include progressive sensorineural hearing loss, imbalance, and ataxia.

Hypoxia-induced changes in standing balance.

Background: A few studies in the literature have reported postural changes with hypoxia, but none have quantified the magnitude of change. Further understanding of this condition could have implications for patients at risk for falls, individuals undergoing acute altitude exposure, and pilots and commercial passengers. The objective of this study was to evaluate the effect of different levels of hypoxia (oxygen nitrogen mixtures) on postural standing balance using the computerized dynamic posturography (CDP) system.

Phase 2 study examining magnesium-dependent tinnitus.

Background: Recent studies in noise-induced and idiopathic sensorineural hearing loss have suggested that magnesium supplementation may lessen both hearing loss and the severity of tinnitus in patients. Further epidemiological evidence indicates that all age groups of Americans fall short of the recommended daily allowance for magnesium by 100 mg daily.

Purpose: The purpose of this study was to examine any potential benefit in lessening the severity of tinnitus in patients taking supplemental magnesium.

Cochlear implant patients with superficial siderosis.

Background: Considered a rare disorder, superficial siderosis of the central nervous system (SSCN) has become more frequently diagnosed in recent years. As it is characterized by progressive sensorineural hearing loss, patients' needs may surpass the capability of hearing aid technology. Despite the retrocochlear nature of the disorder, patients have undergone cochlear implantation (CI) with varying success.

Magnesium and hearing.

The last several decades have revealed clinical and experimental data regarding the importance of magnesium (Mg) in hearing. Increased susceptibility to noise damage, ototoxicity, and auditory hyperexcitability are linked to states of Mg deficiency. Evidence for these processes has come slowly and direct effects have remained elusive because plasma Mg levels do not always correlate with its deficiency.