Effect of Sound Source Location and Spatial Hearing on the Vestibulo-Ocular Reflex.

Background: There have been conflicting results on the effect of auditory stimulation on the vestibulo-ocular reflex (VOR) with some studies indicating suppression, enhancement, or no effect. No studies to date have assessed the effect of sound source location on VOR gain or the relationship between spatial hearing ability and VOR gain.

Purpose: The purpose of the present study was to determine if VOR gain was affected by moving the location of the sound source within participants and to determine if these effects were related to spatial hearing ability.

Vestibular Evoked Myogenic Potentials and Postural Control in Adults with Age-Related Hearing Loss.

Background: Age-related changes to auditory function have been attributed to, through histopathological study, specific degradation of the sensory, supporting, and afferent structures of the cochlea. Similar to age-related hearing loss (ARHL), age-related changes to the vestibular sensory and supporting structures with specific degeneration of the saccule, utricle, otoconia, primary vestibular afferents have also been noted. Significant decreases in postural control with age are also well-documented in the literature attributed to multifactorial changes in function.

Mental tasking and rotary Chair-Induced vestibular nystagmus utilizing Video-Oculography.

To investigate whether the use of mental tasking, when compared to no mental task, affects measurement of nystagmus response with regard to gain, phase & symmetry, and artefact when utilising video-oculography (VOG) as the measurement technique in rotary chair testing (RCT). A within-subject repeated-measures design was utilised. Seventeen (17) healthy adults were evaluated (age 22-25 years).

Effect of Intensity Level and Speech Stimulus Type on the Vestibulo-Ocular Reflex.

Background: Accurate vestibulo-ocular reflex (VOR) measurement requires control of extravestibular suppressive factors such as visual fixation. Although visual fixation is the dominant suppressor and has been extensively studied, the mechanisms underlying suppression from nonvisual factors of attention and auditory stimulation are less clear. It has been postulated that the nonvisual suppression of the VOR is the result of one of two mechanisms: (1) activation of auditory reception areas excites efferent pathways to the vestibular nuclei, thus inhibiting the VOR or (2) cortical modulation of the VOR results from directed attention, which implies a nonmodality-specific process.

Oculomotor Assessment in Children.

Oculomotor evaluation as part of videonystagmography is an integral tool in the assessment of vestibular function providing a global assessment of the neurological pathways associated with oculomotor function. The value of an oculomotor evaluation for pediatric evaluation is well established; however, many questions can also arise with the application to the pediatric population. Oculomotor function is age dependent which can have a significant effect on the test results obtain in children.

Artifact in Pediatric Oculomotor Findings during Videonystagmography: A Retrospective Analysis.

Background: Accurate measurement of oculomotor function using videonystagmography (VNG) is imperative for diagnosis and management of patients with reported dizziness. The oculomotor evaluation during VNG utilizes video-oculography providing valuable information regarding the central structures and pathways that control eye movements. Artifact may have an effect on the overall validity and reliability of VNG oculomotor tracings and can result from patient and/or recording errors.

Mental Tasking and Caloric-Induced Vestibular Nystagmus Utilizing Videonystagmography.

Purpose: The purpose of this study was to quantify the effects of mental tasking on measures of the caloric vestibulo-ocular reflex utilizing videonystagmography as the measurement technique.

Method: A within-subjects repeated-measures design was utilized. Sixteen healthy adults were evaluated (13 women, 3 men; ages 19-31 years).

Pediatric Oculomotor Findings during Monocular Videonystagmography: A Developmental Study.

Background: The differential diagnosis of a dizzy patient >4 yrs old is often aided by videonystagmography (VNG) testing to provide a global assessment of peripheral and central vestibular function. Although the value of a VNG evaluation is well-established, it remains unclear if the VNG test battery is as applicable to the pediatric population as it is for adults. Oculomotor testing specifically, as opposed to spontaneous, positional, and caloric testing, is dependent upon neurologic function.

Treatment of objective and subjective benign paroxysmal positional vertigo.

Background: Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo in adults and is a result of otolithic particles or debris that become free floating within a semicircular canal or adhere to the cupula. Characteristics of BPPV include brief episodes of latent onset vertigo that occur with changes in head position, transient rotary nystagmus beating toward the dependent ear, and reversed nystagmus upon sitting up. Both the vertigo and nystagmus fatigue quickly while maintaining the same head position.