Background:Postural stability in humans is largely maintained by vestibular, visual, and somatosensory inputs to the central nervous system. Recent clinical advances in the assessment of otolith function (e.g., cervical and ocular vestibular evoked myogenic potentials [cVEMPs and oVEMPs], subjective visual vertical [SVV] during eccentric rotation) have enabled investigators to identify patients with unilateral otolith impairments. This research has suggested that patients with unilateral otolith impairments perform worse than normal healthy controls on measures of postural stability. It is not yet known if patients with unilateral impairments of the saccule and/or inferior vestibular nerve (i.e., unilaterally abnormal cVEMP) perform differently on measures of postural stability than patients with unilateral impairments of the horizontal SCC (semicircular canal) and/or superior vestibular nerve (i.e., unilateral caloric weakness). Further, it is not known what relationship exists, if any, between otolith system impairment and self-report dizziness handicap.Purpose:The purpose of this investigation was to determine the extent to which saccular impairments (defined by a unilaterally absent cVEMP) and impairments of the horizontal semicircular canal (as measured by the results of caloric testing) affect vestibulospinal function as measured through the Sensory Organization Test (SOT) of the computerized dynamic posturography (CDP). A secondary objective of this investigation was to measure the effects, if any, that saccular impairment has on a modality-specific measure of health-related quality of life.Research Design:A retrospective cohort study. Subjects were assigned to one of four groups based on results from balance function testing: Group 1 (abnormal cVEMP response only), Group 2 (abnormal caloric response only), Group 3 (abnormal cVEMP and abnormal caloric response), and Group 4 (normal control group).Study Sample:Subjects were 92 adult patients: 62 were seen for balance function testing due to complaints of dizziness, vertigo, or unsteadiness, and 30 served as controls.Intervention:All subjects underwent videonystagmography or electronystagmography (VNG/ENG), vestibular evoked myogenic potentials (VEMPs), self-report measures of self-perceived dizziness disability/handicap (Dizziness Handicap Inventory), and tests of postural control (Neurocom Equitest).Data Collection and Analysis:Subjects were categorized into one of four groups based on balance function test results. All variables were subjected to a multifactor analysis of variance (ANOVA). The Dizziness Handicap Inventory (DHI) total scores and equilibrium scores served as the dependent variables.Results:Results showed that patients with abnormal unilateral saccular or inferior vestibular nerve function (i.e., abnormal cVEMP) demonstrated significantly impaired postural control when compared to normal participants. However, this group demonstrated significantly better postural stability when compared to the group with abnormal caloric responses alone and the group with abnormal caloric responses and abnormal cVEMP results. Patients with an abnormal cVEMP did not differ significantly on the DHI compared to the other two impaired groups.Conclusions:We interpret these findings as evidence that a significantly asymmetrical cVEMP in isolation negatively impacts performance on measures of postural control compared to normal subjects but not compared to patients with significant caloric weaknesses. However, patients with a unilaterally abnormal cVEMP do not differ from patients with significant caloric weaknesses in regard to self-perceived dizziness handicap.

Falls are among the most injurious, costly, and feared conditions affecting older adults. Patients with diabetes have a significantly greater risk for falling due to complications affecting the sensory systems required for balance: vision, proprioception, and vestibular. The effects of diabetes mellitus on the vestibular system are perhaps the least understood of these systems. The vestibular system is complex, includes multiple structures, and is difficult and expensive to thoroughly assess. There is pathophysiologic evidence suggesting a direct effect of diabetes mellitus complications on the vestibular system, but there is limited clinical evidence regarding which specific vestibular structures are most adversely affected. Nevertheless, large population-based studies show that patients with diabetes are more likely to have vestibular loss, have a high prevalence of a specific vestibular disorder called benign paroxysmal positional vertigo, and are at a greater risk for falling. Based on the available evidence, a balance screening and an evaluation of benign paroxysmal positional vertigo, a common but easy to treat pathology, in patients with diabetes is recommended as well as counseling on falls risk and home modifications.

Objectives: The purpose of this study was to assess the effects of cochlear implantation on the functional integrity of the horizontal semicircular canal using multiple methodologies, and to discuss and highlight the limitations of using isolated vestibular tests to assess vestibular function in surgical ears.Methods: Ten cochlear implant patients were consented to undergo a preoperative and 3‐month postoperative vestibular assessment. The horizontal semicircular canal (SCC) was assessed using three different vestibular test measures that assess function using different stimuli and at different frequencies ranges: caloric testing, sinusoidal harmonic acceleration testing in the rotary chair, and video head impulse testing in the plane of the horizontal SCC. Data was analyzed using different methods: descriptive, statistical, and by an examination of individual case studies.Results: Each analysis method yielded a different interpretation. Statistical analysis showed no significant group mean differences between baseline pre‐op vestibular test results and 3‐month post‐op vestibular test results. Descriptive analysis showed 30% of individuals presented with postoperative abnormal vestibular testing findings. A case study examination showed that only one patient presented with a post‐op decrease in vestibular function in the implanted ear.Conclusions: There are several limitations of conventional vestibular testing in postsurgical cochlear implant patients. A test‐battery approach, including case history, and test interpretation made on a case‐by‐case basis is needed to determine whether the patient has undergone vestibular damage, is at risk for falling, or in need of further management.Level of Evidence: 2b individual cohort study.

Introduction: The absence of vertigo during the caloric test, despite a robust response, has been suggested to represent a central vestibular system phenomenon. The purpose of this investigation was to determine the prevalence of absent caloric-induced vertigo perception in an unselected group of patients and to assess possible predicting variables. Methods: Prospective investigation of 92 unselected patients who underwent caloric testing. Inclusion criteria were that each patient generate a maximum slow phase velocity (maxSPV) ≥ 15 deg/sec and a caloric asymmetry of ≤10%. Following the caloric, patients were asked, “Did you have any sensation of motion?” Results: Results showed 75% of patients reported motion with a mean age of 56.51 years compared to a mean age of 66.55 in the 25% of patients reporting an absence of motion. A logistic regression was performed and the overall model was statistically significant accounting for 29% of the variance in caloric perception. The significant predictor variables were patient age and maxSPV of the caloric response. The effect size for both variables was small with an odds ratio of .9 for maxSPV and 1.06 for age. Conclusions: The current investigation showed that both age and maxSPV of the caloric response were significant predictors of vertigo perception during the caloric exam. However, the association between age and caloric perception is not conclusive. Although there is evidence to suggest that these findings represent age-related changes in the central processing of vestibular system stimulation, there are additional unmeasured factors that influence the perception of caloric-induced vertigo.

Purpose: An increase in the 1000/500 Hz frequency amplitude ratio (FAR) of the cervical and ocular vestibular evoked myogenic potentials (cVEMP and oVEMP, respectively) may serve as a potential biomarker for diagnosing Meniere's disease (MD). However, the aging process can also result in an increased FAR for VEMPs. In older patients, distinguishing whether changes in VEMP FAR are due to MD or aging processes becomes difficult. We aimed to investigate the effects of age on VEMP FARs and establish a FAR-normative range for different age groups. Method: cVEMP and oVEMP were recorded from a total of 106 participants grouped as young, middle-aged, and older adults using air-conducted tone bursts at 500, 750, and 1000 Hz at 125 dB pSPL. The FAR was calculated for the cVEMP and oVEMP for the following frequencies: FAR1 = 1000/500, FAR2 = 1000/750, and FAR3 = 750/500. Results: A significant age-related effect was observed on the cVEMP FAR. Although the oVEMP FAR showed an increasing trend with age, it was not statistically significant. Age-based normative FAR values are provided. Conclusions: Drawing from the normative FAR from this study, there is evidence that the existing MD diagnostic criteria would misidentify a considerable number of older adults. Therefore, to reduce false positives, we recommend a more stringent cVEMP and oVEMP FAR criterion in older adults.