Age-Related Changes in Vestibular Evoked Myogenic Potentials

Vestibular mapping in Ramsay-Hunt syndrome and idiopathic sudden sensorineural hearing loss

PURPOSE

To observe vestibular impairment patterns in patients with Ramsay Hunt syndrome with dizziness (RHS_D) and sudden sensorineural hearing loss with dizziness (SSNHL_D) using hierarchical cluster analysis (HCA) to interpret results with possible mechanisms.

METHODS

The data of 30 RHS_D and 81 SSNHL_D patients from January 2017 to August 2022 in a single tertiary referral center were retrospectively analyzed. Video head impulse test (vHIT) and vestibular evoked myogenic potential (VEMP) were used for vestibular analysis of peripheral vestibular organs, and the results of vHIT and VEMP were analyzed. HCA was used to analyze vestibular impairment patterns.

RESULTS

In RHS_D patients, the lateral semicircular canal (LSCC) was the most impaired semicircular canal (SCC), followed by the anterior semicircular canal (ASCC) and the posterior semicircular canal (PSCC), and the utricle was more impaired than the saccule. In SSNHL_D patients, the PSCC was the most impaired SCC, followed by the LSCC and the ASCC, and the utricle was more impaired than the saccule. In HCA of RHS_D patients, the ASCC and utricle were initially clustered, followed by the LSCC, PSCC and saccule in order. In the HCA of SSNHL_D patients, the PSCC was solely merged and independently clustered.

CONCLUSION

There were different patterns of vestibular impairments between RHS_D and SSNHL_D patients. The vestibular analysis and HCA results of SSNHL_D showed tendency of skip lesion, which could be explained by vascular pathophysiology.

Peripheral vestibular loss in noise-exposed firefighters

Introduction

Occupational workers are increasingly aware of the risk of noise overexposure to the auditory system but lack awareness about potential risks to the vestibular system. The purpose of this study was to investigate changes in vestibular end organ function in a known at-risk noise-exposed population, firefighters compared to age- and sex-matched controls using electrophysiologic measures of cervical vestibular evoked myogenic potentials (cVEMP).

Methods

A cross-sectional observational study compared cVEMP response characteristics in 38 noise-exposed firefighters. Firefighters were grouped by years of exposure in the fire service. The cVEMP responses were compared within firefighter groups and between firefighters and age- and sex-matched controls. Dependent variables included the response characteristics of amplitude, latency and threshold.

Results

cVEMP response amplitudes were significantly decreased in firefighters compared to their age- and sex-matched controls. Threshold of the cVEMP responses were significantly higher in firefighters compared to controls and firefighters had a higher incidence of absent cVEMP responses compared to controls. Response amplitudes decreased with increasing years in the fire-service at an increased rate compared to their age- and sex-matched controls. Latency of the cVEMP response was not significantly different in firefighters compared to controls. These findings are consistent with both animal and human studies suggesting noise-induced changes in the sacculocollic pathway.

Discussion

In the absence of any reported vestibular symptoms or auditory indicators of noise-induced hearing loss, these early effects on the vestibular system point to a potential hidden vestibular loss.

Clinical characteristics of vestibular evoked myogenic potentials in children with recurrent vertigo of childhood

OBJECTIVE

To explore the possible pathogenesis of recurrent vertigo of childhood (RVC) and the clinical diagnosis value of vestibular-evoked myogenic potentials (VEMPs).

METHODS

The clinical data of 19 children (5.95 ± 0.38 years) diagnosed with RVC and 17 normal children (5.35 ± 0.31 years) enrolled in the control (NC) group from April 2017 to February 2021 was collected and analyzed. All subjects were tested for both cervical VEMP (cVEMP) and ocular VEMP (oVEMP). The elicit rate, thresholds, N1 latency, P1 latency, interval, amplitude, and amplitude asymmetry ratio (AAR) of VEMPs were compared and analyzed between the two groups.

RESULTS

(1) The elicit rates of cVEMP and oVEMP have no significant difference between the two groups (P > 0.05). (2) The thresholds of cVEMP and oVEMP in the RVC group were higher than that in the NC group (P < 0.05). (3) The N1 latency of cVEMP in the RVC group was longer than that in the NC group (P < 0.05). The P1 latency of cVEMP and latencies of oVEMP have no significant difference between the two groups (P > 0.05). (4) The interval of cVEMP in the RVC group was longer than that in the NC group (P < 0.05), while the interval of oVEMP has no significant difference between the two groups (P > 0.05). (5) The amplitude of cVEMP in the RVC group was higher than that in the NC group (P < 0.05), while the amplitude of oVEMP was similar in the two groups (P > 0.05). (6) The AAR values of oVEMP and cVEMP were similar in the two groups (P > 0.05).

CONCLUSIONS

The elicit rates of VEMPs in children with RVC did not differ from that of normal children, but the thresholds were all increased, suggesting reduced sensitivity of the otolith organ and vestibular nerve conduction pathways. The P1 latency of cVEMP was normal in children with RVC, but N1 latency and interval of cVEMP were increased, we finally reached a conclusion that there might be potential impairment in the inferior vestibular nerve and the subsequent nerve conduction pathway in RVC.

Effects of Age and Middle Ear on the Frequency Tuning of the cVEMP and oVEMP

BACKGROUND

Upward shift in the air conducted (AC) frequency tuning of vestibular evoked myogenic potentials (VEMPs) as an effect of aging is hypothesized to be due to the microstructural stiffening changes in the inner ear. However, with an AC stimulus, it may be possible that the shift in the frequency tuning of VEMPs as an effect of aging may also be due to contributions from the middle ear.

PURPOSE

The main aim of this study was to examine the effects of age on the frequency tuning of the cervical VEMP (cVEMP) and ocular VEMP (oVEMP) and determine the role of middle ear transmission characteristics in shaping these effects.

RESEARCH DESIGN

Standard group comparison.

STUDY SAMPLE

One-hundred seven participants divided in three groups: young adult, middle-age, and older adults with "normal" middle ear and negative history of neurological or vestibular complaints.

DATA COLLECTION AND ANALYSES

Middle ear measures included static admittance and middle ear resonant frequency. cVEMP and oVEMPs were elicited with AC tone bursts at 500, 750, and 1,000 Hz.

RESULTS

No significant effect of age was observed on any of the middle ear measures. There was a significant effect of age on the amplitude of the cVEMP, but this effect was frequency specific. The age-related reduction in cVEMP corrected amplitude was only observed when the eliciting stimulus was 500 or 750 Hz, with no significant effect observed with a 1,000 Hz stimulus. For the oVEMP, the effects of age were apparent at all stimulus frequencies. We also observed a general upward shift in the frequency tuning of both the cVEMP and oVEMP for middle-age and older adults, with 750 and 1,000 Hz yielding higher response rates and larger amplitudes among middle-aged and older adults. Measurements of middle ear did not significantly contribute to the observed findings.

CONCLUSIONS

The upward shift in frequency tuning of VEMPs among middle age and older adults could be due to the changes in the vestibular system and not from the middle ear. These results support the use of different frequency stimuli (i.e., 750 or 1,000 Hz) to elicit a VEMP if a response is absent using a 500 Hz stimulus, especially in patients over the age of 40.

The Influence of Motoric Maneuvers on Cervical Vestibular Evoked Myogenic Potentials (cVEMPs)

BACKGROUND

The cervical vestibular evoked myogenic potential (cVEMP) is a vestibular response that is produced by the saccule in response to intense, often low-frequency, short-duration auditory stimuli, and is typically recorded from a contracted sternocleidomastoid (SCM) muscle. Previous research has shown that the amplitude of the cVEMP is related to the amount of SCM electromyographic (EMG) activity.

PURPOSE

The aim of this study was to determine the influence of various remote motoric maneuvers on the amplitude of the cVEMP, as well as whether they influence the level of SCM EMG activity.

RESEARCH DESIGN

The cVEMP was recorded from the left SCM muscle to left ear stimulation, in response to the SCM condition, as well as three different motoric maneuvers (jaw clench, eye closure, and the Jendrassik maneuver). EMG activity was also varied between 50, 75, and 100% of maximal EMG activity.

STUDY SAMPLE

Data from 14 healthy subjects, with a mean age of 25.57 years (standard deviation = 5.93 years), was included in the present study.

DATA COLLECTION AND ANALYSIS

Mean latency and amplitude of the cVEMP were compared across the four conditions and varying magnitudes of EMG contraction. SPSS 26 was used to statistically analyze the results.

RESULTS

cVEMP latency did not vary across condition. cVEMP amplitude decreased with decreasing EMG magnitude. SCM contraction with jaw clench produced the largest increase in cVEMP amplitude; however, this condition was not significantly different from the SCM condition alone. SCM contraction with the Jendrassik maneuver produced a cVEMP amplitude that was similar and not statistically different from SCM contraction alone, and the addition of the eye closure maneuver to SCM contraction resulted in the lowest cVEMP amplitude, which was found to be statistically different from the standard SCM condition at 100 and 75% EMG activity. The amplitude relationship across the conditions was not found to vary with changes in EMG activity; however, a significant increase in EMG amplitude was found during the 50% muscle contraction condition when subjects performed the Jendrassik maneuver in addition to the standard SCM contraction.

CONCLUSIONS

The addition of the eye closure maneuver to SCM contraction resulted in a significant decrease in cVEMP amplitude, while the addition of the Jendrassik maneuver resulted in a significant increase in EMG activity at the lowest level of SCM activation (i.e., 50%). Additional research is necessary to determine how motoric maneuvers influence the cVEMP amplitude, and whether the results are also dependent on how SCM contraction is being produced (e.g., while supine vs. sitting).

Differentiating neurodegenerative parkinsonian syndromes using vestibular evoked myogenic potentials and balance assessment

OBJECTIVE

Vestibular evoked myogenic potentials (VEMP) were investigated to differentiate between parkinsonian syndromes. We correlated balance and VEMP parameters to investigate the VEMP brainstem circuits as possible origin for postural instability.

METHODS

We assessed clinical status, ocular and cervical VEMP (oVEMP, cVEMP) and conducted a balance assessment (posturography, Activities-specific Balance Confidence Scale, Berg Balance Scale, modified Barthel Index) in 76 subjects: 30 with Parkinson's disease (PD), 16 with atypical parkinsonism (AP) and 30 healthy controls. VEMP were elicited by using a mini-shaker on the forehead.

RESULTS

Patients with PD had a prolonged oVEMP n10 in comparison to controls and prolonged p15 compared to controls and AP. Patients with AP showed reduced oVEMP amplitudes compared to PD and controls. CVEMP did not differ between groups. Postural impairment was higher in AP compared to controls and PD, particularly in the rating scales. No correlations between VEMP and posturography were found. A support vector machine classifier was able to automatically classify controls and patient subgroups with moderate to good accuracy based on oVEMP latencies and balance questionnaires.

CONCLUSIONS

Both oVEMP and posturography, but not cVEMP, may be differentially affected in PD and AP. We did not find evidence that impairment of the cVEMP or oVEMP pathways is directly related to postural impairment.

SIGNIFICANCE

OVEMP and balance assessment could be implemented in the differential diagnostic work-up of parkinsonian syndromes.

Elevated ocular VEMP responses in the absence of a superior semicircular canal dehiscence

BACKGROUND

Vestibular evoked myogenic potentials (VEMPs) have an accepted role in the diagnosis of the superior semicircular canal dehiscence (SSCD) syndrome. The current impression is that ocular VEMPs (oVEMPs) are more sensitive than cervical VEMPs (cVEMPs) for detecting a SSCD and that oVEMP testing in response to air conducted sound provides an excellent screening test without risk of radiation exposure from computerized tomography (CT).

AIMS/OBJECTIVES

To report on patients with elevated oVEMP amplitudes but without evidence for a SSCD on multiplanar CT imaging.

MATERIAL AND METHODS

Retrospective chart review of all patients referred for vestibular function testing to our department. Patients with oVEMP peak-to-peak amplitudes ≥17 μν without evidence for a SSCD on imaging were evaluated.

RESULTS

26 patients had oVEMP peak-to-peak amplitudes ≥17 μν with no evidence of a SSCD on imaging. The most common diagnosis was Meniere's disease in those identified.

CONCLUSION AND SIGNIFICANCE

oVEMPs can provide false positive results for diagnosis of a SSCD and an elevated oVEMP amplitude in itself is insufficient for diagnosis of a SSCD.

Methodological aspects of testing vestibular evoked myogenic potentials in infants at universal hearing screening program

Motor development in infants is dependent upon the function of the inner ear balance organ (vestibular organ). Vestibular failure causes motor delays in early infancy and suboptimal motor skills later on. A vestibular test for newborns and infants that is applicable on a large scale, safe and cost effective is in demand in various contexts: in the differential diagnosis of early onset hearing loss to determine forms associated with vestibular failure; in early hearing habilitation with cochlear implant, indicating the vestibular predominant side; and in the habilitation of children affected by motor skill disorders, revealing the contribution of a vestibular failure. This work explored the feasibility of cervical vestibular evoked myogenic potentials (VEMP) in conjunction with newborn universal hearing screening program. VEMP was measured after the hearing tests and was evoked by bone-conducted stimuli. Moreover, stimulus delivery was regulated by neck muscle activity, with infants rested unconstrained in their parents´ arms and with the head supported by the operator´s hand. This VEMP protocol showed a high level of feasibility in terms of test viability and result reproducibility. VEMP integrated into the newborn hearing screening program may represent a practical method for large-scale assessment of balance function in infants.

The occlusion effect in bone conducted cVEMP

BACKGROUND

Vestibular evoked myogenic potentials (VEMP) are transient alteration in tonic activity of muscles elicited by auditory stimulation of the otolithic organs of the ear. VEMP can be triggered by auditory stimulation via air or bone conduction. Occlusion of the external auditory meatus has long been known to decrease thresholds for sound perception medicated by the cochlea.

OBJECTIVE

Proof that the occlusion effect is present for bone conducted (BC) cervical VEMPs (cVEMP).

METHODS

Measurement of the thresholds and raw amplitudes of BC-VEMPs in twenty healthy adults with the external auditory canal open and occluded.

RESULTS

Thresholds for BC-VEMPs were similar for the open vs. the occluded condition. However, amplitudes were statistically significantly higher in the occluded (average 76.34μV) vs. open group (average 69.9μV).

CONCLUSIONS

The occlusion effect is present in cVEMPs. This finding, described herein for the first time, has a number of clinical implications such as the surgically altered ear and the use of occluding hearing aids.

Presbyvestibulopathy: Diagnostic criteria Consensus document of the classification committee of the Bárány Society

This paper describes the diagnostic criteria for presbyvestibulopathy (PVP) by the Classification Committee of the Bárány Society. PVP is defined as a chronic vestibular syndrome characterized by unsteadiness, gait disturbance, and/or recurrent falls in the presence of mild bilateral vestibular deficits, with findings on laboratory tests that are between normal values and thresholds established for bilateral vestibulopathy.

The diagnosis of PVP is based on the patient history, bedside examination and laboratory evaluation. The diagnosis of PVP requires bilaterally reduced function of the vestibulo-ocular reflex (VOR). This can be diagnosed for the high frequency range of the VOR with the video-HIT (vHIT); for the middle frequency range with rotary chair testing; and for the low frequency range with caloric testing.

For the diagnosis of PVP, the horizontal angular VOR gain on both sides should be < 0.8 and > 0.6, and/or the sum of the maximal peak velocities of the slow phase caloric-induced nystagmus for stimulation with warm and cold water on each side should be < 25°/s and > 6°/s, and/or the horizontal angular VOR gain should be > 0.1 and < 0.3 upon sinusoidal stimulation on a rotatory chair.

PVP typically occurs along with other age-related deficits of vision, proprioception, and/or cortical, cerebellar and extrapyramidal function which also contribute and might even be required for the manifestation of the symptoms of unsteadiness, gait disturbance, and falls. These criteria simply consider the presence of these symptoms, along with documented impairment of vestibular function, in older adults.

Effect of vestibular rehabilitation on recovery rate and functioning improvement in patients with chronic unilateral vestibular hypofunction and bilateral vestibular hypofunction

BACKGROUND

The minimal number of studies have documented the impact of Vestibular rehabilitation (VR) on the recovery rate of patients with Chronic Unilateral Vestibular Hypofunction (CUVH) and Bilateral Vestibular Hypofunction (BVH).

OBJECTIVES

The goal of the study was to show and compare the impact of vestibular rehabilitation (VR) in patients with CUVH and BVH.

METHODS

We analysed the data of 30 patients with CUVH and 20 with BVH treated with VR. The patients with CUVH during their eight-week treatment were controlled every two weeks, while the patients with BVH were controlled every three months during their one-year treatment; they filled in the DHI and ABC questionnaires every time.

RESULTS

In both groups of patients, there was significantly less disablement between the initial and final DHI scores (from 59-20 in CUVH and 74-41 in BVH group). There was a significant increase in the balance confidence between the initial and final ABC Scale in both groups of patients (from 49.5-90% in CUVH and 42-73% in BVH group).

CONCLUSIONS

Well-planned and individually adjusted system of vestibular exercises leads to a significant decrease in clinical symptoms and improvement of functioning and confidence in activities in both the CUVH and the BVH patients.

Postural responses of galvanic vestibular stimulation: comparison between groups of older adults and young people

Abstract Objective: To evaluate the effect of vestibular manipulation on the postural sway and muscle activation of younger and older adults. Methods: The study analyzed the effects of three intensity levels of galvanic vestibular stimulation (GVS) (0.3; 0.6 and 1m) on the pattern of muscle activity and center of pressure (CP) displacements of 12 older adults (EG) and 12 young adults (CG) while maintaining their balance on a stable surface, with no vision. Results: The EG showed a positive correlation between CP displacement and muscle activity and GVS intensity. On the other hand, the magnitude of postural response in the EG was not modulated in accordance with GVS intensities. Additionally, during the highest GVS intensity level (1 mA) greater muscle activity was used to increase stiffness, decrease the amplitude of oscillation and ensure stability. This unusual response characterizes a pattern of co-activation and is perhaps a safety mechanism to ensure stability. Conclusion: The EG individuals were not able to select the appropriate motor strategy to efficiently compensate the effects of GVS. This unusual strategy reflects deficits in the vestibular system of older adults, a fact which negatively interferes with their ability to reevaluate sensory information.

Vestibular myogenic potentials evoked by air-conducted stimuli at safe acoustic intensity levels retain optimal diagnostic properties for superior canal dehiscence syndrome

BACKGROUND

Vestibular-evoked myogenic potential (VEMP) is commonly conducted with air-conducted (AC) stimuli whose intensity may exceed the prudential levels of acoustic exposure in susceptible subjects.

OBJECTIVES

To determine the diagnostic accuracy of AC VEMP for superior canal dehiscence syndrome (SCDS) at lowered acoustic stimulation levels.

MATERIAL AND METHODS

VEMP was tested in 10 SCDS patients and in 10 age/sex matched control subjects. VEMP were recorded on cervical muscles (cVEMP) and extraocular muscles (oVEMP) in response to short AC tone bursts at 500, 1000 and 2000 Hz delivered at 80 dB nHL (103 dB peSPL). Parameters of interest were the response amplitude and the frequency tuning.

RESULTS

VEMP evoked by AC stimuli at safe acoustic stimulation levels did effectively separate SCDS patients from healthy controls. The separation was optimal at all the frequencies tested, however 500 Hz resulted the best VEMP tuning frequency, especially at oVEMP.

CONCLUSIONS

Lowering the AC stimulation to the levels compatible with testing of patients susceptible to acoustic exposure didn't affect the VEMP diagnostic properties for SCDS.

SIGNIFICANCE

SCDS may be screened by VEMP even among subjects susceptible for acoustic exposure.

The Vestibular System and Ageing

The world's population is ageing due to increased hygiene and improved medical care. Dizziness and imbalance frequently affect the elderly and is most common among individuals over the age of 60. In this age group approximately 30% of the population experience these debilitating symptoms at some point. They contribute to falls and frailty, which often result in hospitalization causing tremendous cost for the health care systems, and increased mortality. To make the matters worse balance disorders are often complex. Physicians face the difficulty of diagnosing the patient with the exact disorder especially since each disorder may manifest differently in each patient. In addition, several treatment options exist, however, with a low level of evidence. This chapter summarizes the underlying degenerative processes of the peripheral as well as the central vestibular system, diagnostic tools, the most common balance disorders in the elderly, and possible treatment options of these disorders.

Aging and the peripheral vestibular system

Whereas much has been learned about age-related auditory changes in the inner ear, relatively little is known about the aging effects on the vestibular part of the inner ear-the peripheral vestibular system. Here we review relevant literature with regard to the prevalence of vestibular dysfunction, vestibular functional and structural changes in the elderly. The prevalence of vestibular dysfunction increases with age. Functionally, as age increases, VEMP amplitudes decrease, VEMP thresholds increase, VOR gain of HIT decreases. Due to the complexity of the vestibular system, variations in subject age and measurement techniques, findings in VEMP latency and caloric tests are conflicting. To address this, a direct measure of the peripheral vestibular system should be applied. Structurally, age-related loss in vestibular ganglion and otoconia have been noted; hair cell changes are not well defined; while subcellular changes remain to be explored. Defining how the onset of vestibular dysfunction correlates with structural degeneration will offer insights into the mechanisms underlying vestibular aging.

Aging

This chapter reviews studies that have examined age-related anatomic and functional changes in sensory, neuromuscular, and cognitive systems that impair the control of balance and gait. Specifically, we examine age-related changes in peripheral systems: lower-limb sensation, visual functions such as contrast sensitivity and depth perception, vestibular sense, strength, and power in the lower-limb muscle groups, as well as central factors including processing speed and executive functioning. Significant impairments in any one of the above systems can predispose older people to falls, with the risk of falling increasing substantially with the number of impairments present. There is increasing evidence that interventions aimed at addressing specific sensory and neuromuscular impairments can improve balance control and reduce fall risk. In particular, task-specific exercise can improve muscle strength, balance, gait and mobility and prevent falls in older people.

Cervical and Ocular VEMP Testing in Diagnosing Superior Semicircular Canal Dehiscence

Objective To determine the sensitivity and specificity of ocular and cervical vestibular evoked myogenic potentials (VEMPs) in the diagnosis of superior semicircular canal dehiscence (SCD) and to describe the VEMP response characteristics that are most sensitive to SCD and compare the findings to previous reports. Study Design Case series with chart review. Setting Two tertiary neurotologic referral centers. Subjects and Methods Cervical and ocular VEMP peak-to-peak amplitudes and thresholds from 39 adult patients older than 18 years with surgically confirmed SCD were compared with 84 age-matched controls. Results Using receiver operating characteristic (ROC) curves, cervical VEMP (cVEMP) amplitudes, cVEMP thresholds, and ocular VEMP (oVEMP) amplitudes had areas under the curve of 0.731, 0.912, and 0.856, respectively, all of which were statistically significant ( P < .0001). For cVEMP thresholds, at the clinical equivalent ≤85-dB normalized hearing level (nHL) threshold, the sensitivity and specificity were 97.3% and 31.3%, respectively. At the ≤70-dB nHL threshold, the sensitivity and specificity were 73.0% and 94.0%, respectively. For oVEMP amplitudes >12.0 µV, the sensitivity and specificity were 78.6% and 81.7%, respectively. Conclusion Data from this multicenter study suggest that both cVEMP thresholds and oVEMP amplitudes remain good diagnostic tests for identifying SCD, with each test dependent on a number of factors. The sensitivity and specificity of these individual tests may vary slightly between centers depending on testing parameters used.

Age-Related Vestibular Loss: Current Understanding and Future Research Directions

The vestibular system sub-serves a number of reflex and perceptual functions, comprising the peripheral apparatus, the vestibular nerve, the brainstem and cerebellar processing circuits, the thalamic relays, and the vestibular cerebral cortical network. This system provides signals of self-motion, important for gaze and postural control, and signals of traveled distance, for spatial orientation, especially in the dark. Current evidence suggests that certain aspects of this multi-faceted system may deteriorate with age and sometimes with severe consequences, such as falls. Often the deterioration in vestibular functioning relates to how the signal is processed by brain circuits rather than an impairment in the sensory transduction process. We review current data concerning age-related changes in the vestibular system, and how this may be important for clinicians dealing with balance disorders.

Vestibular-evoked myogenic potentials

The vestibular-evoked myogenic potential (VEMP) is a short-latency potential evoked through activation of vestibular receptors using sound or vibration. It is generated by modulated electromyographic signals either from the sternocleidomastoid muscle for the cervical VEMP (cVEMP) or the inferior oblique muscle for the ocular VEMP (oVEMP). These reflexes appear to originate from the otolith organs and thus complement existing methods of vestibular assessment, which are mainly based upon canal function. This review considers the basis, methodology, and current applications of the cVEMP and oVEMP in the assessment and diagnosis of vestibular disorders, both peripheral and central.

Association Between Visuospatial Ability and Vestibular Function in the Baltimore Longitudinal Study of Aging

OBJECTIVES

To investigate the relationship between vestibular loss associated with aging and age-related decline in visuospatial function.

DESIGN

Cross-sectional analysis within a prospective cohort study.

SETTING

Baltimore Longitudinal Study of Aging (BLSA).

PARTICIPANTS

Community-dwelling BLSA participants with a mean age of 72 (range 26-91) (N = 183).

MEASUREMENTS

Vestibular function was measured using vestibular-evoked myogenic potentials. Visuospatial cognitive tests included Card Rotations, Purdue Pegboard, Benton Visual Retention Test, and Trail-Making Test Parts A and B. Tests of executive function, memory, and attention were also considered.

RESULTS

Participants underwent vestibular and cognitive function testing. In multiple linear regression analyses, poorer vestibular function was associated with poorer performance on Card Rotations (P = .001), Purdue Pegboard (P = .005), Benton Visual Retention Test (P = 0.008), and Trail-Making Test Part B (P = .04). Performance on tests of executive function and verbal memory were not significantly associated with vestibular function. Exploratory factor analyses in a subgroup of participants who underwent all cognitive tests identified three latent cognitive abilities: visuospatial ability, verbal memory, and working memory and attention. Vestibular loss was significantly associated with lower visuospatial and working memory and attention factor scores.

CONCLUSION

Significant consistent associations between vestibular function and tests of visuospatial ability were observed in a sample of community-dwelling adults. Impairment in visuospatial skills is often one of the first signs of dementia and Alzheimer's disease. Further longitudinal studies are needed to evaluate whether the relationship between vestibular function and visuospatial ability is causal.

Association between saccular function and gait speed: data from the Baltimore Longitudinal Study of Aging

OBJECTIVE

To investigate whether otolith function (saccular and utricular) is associated with walking performance.

STUDY DESIGN

Cross-sectional analysis of observational data collected in the Baltimore Longitudinal Study of Aging.

SETTING

National Institute on Aging Intramural Research Program Clinical Research Unit at Harbor Hospital, Baltimore, Maryland.

PATIENTS

Community-dwelling participants.

INTERVENTION(S)

Cervical and ocular vestibular evoked myogenic potentials (VEMPs) were used to assess saccular and utricular function, respectively.

MAIN OUTCOME MEASURE(S)

Cervical and ocular VEMP latency and amplitude responses and usual, rapid, and narrow (20 cm) gait speed assessed over a 6-m course.

RESULTS

In 314 participants (mean age, 73.1 yr; range, 26-96 yr), cervical VEMP amplitude mediated the association between age and gait speed-particularly narrow walk speed-in both men and women. Cervical VEMP latency had an independent association with gait speed in age-, height-, and weight-adjusted analyses, although the direction of the association differed by sex. Greater cervical VEMP latency was associated with slower usual, rapid, and narrow gait speed in women but faster rapid gait speed in men. Neither the amplitude nor latency of ocular VEMP was associated with gait speed in men or women.

CONCLUSION

These findings suggest that age-related slowing of gait speed is in part mediated by the decreased magnitude of saccular response associated with age. The sex-related differential association between saccular response latency and gait speed requires further study.

Aging of the Human Vestibular System

Aging affects every sensory system in the body, including the vestibular system. Although its impact is often difficult to quantify, the deleterious impact of aging on the vestibular system is serious both medically and economically. The deterioration of the vestibular sensory end organs has been known since the 1970s; however, the measurable impact from these anatomical changes remains elusive. Tests of vestibular function either fall short in their ability to quantify such anatomical deterioration, or they are insensitive to the associated physiologic decline and/or central compensatory mechanisms that accompany the vestibular aging process. When compared with healthy younger individuals, a paucity of subtle differences in test results has been reported in the healthy older population, and those differences are often observed only in response to nontraditional and/or more robust stimuli. In addition, the reported differences are often clinically insignificant insomuch that the recorded physiologic responses from the elderly often fall within the wide normative response ranges identified for normal healthy adults. The damaging economic impact of such vestibular sensory decline manifests itself in an exponential increase in geriatric dizziness and a subsequent higher prevalence of injurious falls. An estimated $10 to $20 billion dollar annual cost has been reported to be associated with falls-related injuries and is the sixth leading cause of death in the elderly population, with a 20% mortality rate. With an estimated 115% increase in the geriatric population over 65 years of age by the year 2050, the number of balanced-disordered patients with a declining vestibular system is certain to reach near epidemic proportions. An understanding of the effects of age on the vestibular system is imperative if clinicians are to better manage elderly patients with balance disorders, dizziness, and vestibular disease.

Association Between Vestibular and Cognitive Function in U.S. Adults: Data From the National Health and Nutrition Examination Survey

BACKGROUND

Vestibular function declines with age, and emerging evidence suggests that vestibular loss is associated with cognitive impairment. Whether vestibular dysfunction is associated with age-related cognitive decline is unknown.

METHODS

We used data from the 1999-2002 National Health and Nutrition Examination Surveys to evaluate the influence of vestibular function on cognitive performance in a nationally representative sample of U.S. adults aged ≥60 years (n = 1,303). Vestibular function was measured with the modified Romberg test, and cognitive function was measured by the digit symbol substitution (DSS) score test. We also developed structural equation models (SEMs) to explore whether vestibular dysfunction and associated cognitive impairment mediate the effect of age on falls and activities of daily living (ADL) difficulty.

RESULTS

Vestibular dysfunction was present in 58% of the study population. In multivariate analyses, vestibular dysfunction was associated with a 3.4-point lower DSS score (95% confidence interval: -5.2, -1.6; p < .0001), equivalent to the effect of 5 years of age. Vestibular dysfunction was also associated with a significantly higher odds of ADL difficulty (p = .001), and with a 2.6-fold increase in the odds of falling (p = .017). SEMs suggested that vestibular function mediates 14.3% of the effect of age on cognitive performance. Further SEMs suggested that lower cognitive performance mediates the association between vestibular loss and ADL difficulty as well as falls.

CONCLUSIONS

This study suggests that vestibular dysfunction partially mediates the association between age and cognitive impairment. Moreover, the cognitive impairment that results from vestibular loss may contribute to ADL difficulty and falls in older individuals.

Epidemiology of vestibular evoked myogenic potentials: Data from the Baltimore Longitudinal Study of Aging

OBJECTIVE

To evaluate whether age-related changes in vestibular evoked myogenic potentials (VEMPs) differ by demographic and cardiovascular risk groups.

METHODS

Participants in the Baltimore Longitudinal Study of Aging underwent cervical and ocular VEMP testing. VEMP latency, amplitude, asymmetry ratios, and prevalence of absent responses were compared across demographic and cardiovascular risk groups.

RESULTS

In 257 participants (mean age 72.9, 57% female), ocular VEMP (oVEMP) n10 latency increased by 0.12ms/decade while amplitude decreased by 2.9μV/decade. Black participants had better oVEMP function (shorter latency, increased amplitude, and decreased odds of absent responses) relative to white participants. In 250 participants (mean age 72.6, 54% female), EMG-corrected cervical VEMP (cVEMP) amplitude decreased by 0.14μV/decade and p13 latency was 0.38ms longer in males. The odds of absent responses were significantly higher in individuals age ⩾80 for oVEMPs, and age ⩾70 for cVEMPs. Cardiovascular risk factors had no association with VEMP parameters.

CONCLUSIONS

We confirmed age-related declines in otolith function, and observed a protective effect of black race on oVEMP latency and amplitude.

SIGNIFICANCE

These results illustrate how measures of otolith function change with age in community-dwelling adults. Further investigations are needed to ascertain whether better otolith function in blacks might contribute to a lower risk of mobility disability and falls.

[Characteristics of dizziness in elderly]

Clinical features of the main diseases that may cause dizziness in elderly and approaches to its treatment are reviewed. The treatment plan and increase of its effectiveness as well as prevention of the complications and improvement of quality of life of patients should be based on these features.

Effects of age on the tuning of the cVEMP and oVEMP

OBJECTIVES

The purpose of the present investigation was to define for young, middle-aged, and older adults the optimal frequency (cies) to record both the cervical vestibular-evoked myogenic potential (cVEMP) and the ocular vestibular-evoked myogenic potential (oVEMP). Further, this study aimed to describe age-related changes in the tuning of these two vestibular-evoked myogenic potentials.

DESIGN

This was a prospective study. Participants were 39 healthy adults (mean age 46.3 ± 15.7 years; range = 22 to 78 years; 15 men) equally divided into 3 age groups of 13 participants each: young adult (18 to 39 years), middle age (40 to 59 years), and old adult (≥60 years). cVEMPs and oVEMPs were recorded using air-conduction tone bursts at stimulus frequencies of 125, 250, 500, 750, 1000, 1500, and 2000 Hz presented at 127 dB pSPL.

RESULTS

There was a significant main effect of age group and frequency on the amplitude of both the cVEMP and the oVEMP. Amplitudes were largest for the Young adult group for the cVEMP and for the young adult and Middle age group for the oVEMP. The largest average peak-to-peak amplitude occurred in response to a 750 Hz tone burst for both responses. No significant differences in mean amplitude of the cVEMP or oVEMP were observed for 500, 750, or 1000 Hz stimuli. There was a significant interaction of age group and frequency for the cVEMP, suggesting a loss of tuning for the old adult group. Compared with the young adult group, the tuning of the cVEMP and oVEMP for the older adjults appeared to shift to a higher frequency.

CONCLUSION

There is no sharp tuning in the saccule and utricle. Instead, there is a range of best frequencies that may be used to evoke the cVEMP and oVEMP responses. The results of the present investigation also demonstrate that the optimal stimulus frequency to elicit a VEMP may change with age. Accordingly, 500 Hz may not be the ideal frequency to elicit VEMPs for all age groups. For this reason, in cases where the VEMP response is absent at 500 Hz it is recommended that attempts be made to record the VEMP for tone-burst frequencies of 750 or 1000 Hz.

Clinical uses of cervical vestibular-evoked myogenic potential testing in pediatric patients

To demonstrate the feasibility and clinical significance of cervical vestibular-evoked myogenic potential (cVEMP) test in pediatric patients.Retrospective review study was conducted in a pediatric tertiary care facility. A total of 278 patients were identified with adequate data, including medical notes, results of cVEMP, and imaging studies.Among the total of 278 pediatric patients, only 3 children were not able to finish the cVEMP test successfully. In about 90% of the cases, the cVEMP test was requested to investigate a patient's hearing loss and/or vestibular complaints. Over 90% of the cVEMP tests were ordered by specialists such as pediatric otolaryngologists or otologists. Obtained cVEMP results provided useful information in clinical diagnosis and management in all cases.It is feasible to conduct cVEMP testing in children, including infants, and cVEMP testing can provide valuable information in the diagnosis and management of hearing loss and vestibular impairment. This simple and noninvasive test should be embraced by pediatric professionals.

Dizziness and Imbalance in the Elderly: Age-related Decline in the Vestibular System

Dizziness and imbalance are amongst the most common complaints in older people, and are a growing public health concern since they put older people at a significantly higher risk of falling. Although the causes of dizziness in older people are multifactorial, peripheral vestibular dysfunction is one of the most frequent causes. Benign paroxysmal positional vertigo is the most frequent form of vestibular dysfunction in the elderly, followed by Meniere's disease. Every factor associated with the maintenance of postural stability deteriorates during aging. Age-related deterioration of peripheral vestibular function has been demonstrated through quantitative measurements of the vestibulo-ocular reflex with rotational testing and of the vestibulo-collic reflex with testing of vestibular evoked myogenic potentials. Age-related decline of vestibular function has been shown to correlate with the age-related decrease in the number of vestibular hair cells and neurons. The mechanism of age-related cellular loss in the vestibular endorgan is unclear, but it is thought that genetic predisposition and cumulative effect of oxidative stress may both play an important role. Since the causes of dizziness in older people are multi-factorial, management of this disease should be customized according to the etiologies of each individual. Vestibular rehabilitation is found to be effective in treating both unilateral and bilateral vestibular dysfunction. Various prosthetic devices have also been developed to improve postural balance in older people. Although there have been no medical treatments improving age-related vestibular dysfunction, new medical treatments such as mitochondrial antioxidants or caloric restriction, which have been effective in preventing age-related hearing loss, should be ienvestigated in the future.

International guidelines for the clinical application of cervical vestibular evoked myogenic potentials: an expert consensus report

BACKGROUND

Cervical vestibular evoked myogenic potentials (cVEMPs) are electromyogram responses evoked by high-level acoustic stimuli recorded from the tonically contracting sternocleidomastoid (SCM) muscle, and have been accepted as a measure of saccular and inferior vestibular nerve function. As more laboratories are publishing cVEMP data, there is a wider range of recording methods and interpretation, which may be confusing and limit comparisons across laboratories.

OBJECTIVE

To recommend minimum requirements and guidelines for the recording and interpretation of cVEMPs in the clinic and for diagnostic purposes.

MATERIAL AND METHODS

We have avoided proposing a single methodology, as clinical use of cVEMPs is evolving and questions still exist about its underlying physiology and its measurement. The development of guidelines by a panel of international experts may provide direction for accurate recording and interpretation.

RESULTS

cVEMPs can be evoked using air-conducted (AC) sound or bone conducted (BC) vibration. The technical demands of galvanic stimulation have limited its application. For AC stimulation, the most effective frequencies are between 400 and 800 Hz below safe peak intensity levels (e.g. 140 dB peak SPL). The highpass filter should be between 5 and 30 Hz, the lowpass filter between 1000 and 3000 Hz, and the amplifier gain between 2500 and 5000. The number of sweeps averaged should be between 100 and 250 per run. Raw amplitude correction by the level of background SCM activity narrows the range of normal values. There are few publications in children with consistent results.

CONCLUSION

The present recommendations outline basic terminology and standard methods. Because research is ongoing, new methodologies may be included in future guidelines.

Air-conducted oVEMPs provide the best separation between intact and superior canal dehiscent labyrinths

OBJECTIVE

First, to define the best single-step suprathreshold screening test for superior canal dehiscence syndrome (SCDS); second, to obtain further insight into the relative sensitivity of vestibular afferents to sound vibration in the presence of a superior canal dehiscence.

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral center.

PATIENTS

Eleven patients with surgically confirmed SCDS (mean, 50 yr; range, 32-66 yr) and 11 age-matched, healthy subjects (right ear only) with no hearing or vestibular deficits (mean, 50 yr; range, 33-66 yr).

INTERVENTION

All subjects completed ocular and cervical vestibular evoked myogenic potential (o- and cVEMP) testing in response to air conduction (click and 500 Hz tone burst) and midline bone conduction (reflex hammer and Mini-shaker) stimulation.

MAIN OUTCOME MEASURES

OVEMP n10 amplitude and cVEMP corrected peak-to-peak amplitude.

RESULTS

OVEMP n10 amplitudes were significantly higher in SCDS when compared with healthy controls in response to all stimuli with the exception of reflex hammer. Likewise, cVEMP-corrected peak-to-peak amplitudes were significantly higher in SCDS when compared with healthy controls for air conduction stimulation (click and 500 Hz toneburst). However, there were no significant differences between groups for midline taps (reflex hammer or mini-shaker). Receiver operating characteristic curves demonstrated that oVEMPs in response to air conduction stimulation provided the best separation between SCDS and healthy controls.

CONCLUSION

OVEMPs in response to air conduction stimulation (click and 500 Hz toneburst) provide the best separation between SCDS and healthy controls and are therefore the best single-step screening test for SCDS.

Decline in semicircular canal and otolith function with age

OBJECTIVE

To characterize the physiologic nature of the vestibular dysfunction that occurs with the normative aging process.

STUDY DESIGN

Cross-sectional study.

SETTING

Tertiary care academic medical center.

PATIENTS

Fifty individuals age 70 years and above.

INTERVENTIONS

Head thrust dynamic visual acuity testing and cervical and ocular vestibular-evoked myogenic potential (VEMP) testing.

MAIN OUTCOME MEASURES

Semicircular canal function measured by head thrust dynamic visual acuity testing in each of the 3 semicircular canal planes, and saccular and utricular function measured by cervical VEMP and ocular VEMP testing, respectively.

RESULTS

We observed significant declines in semicircular canal function in each of the canal planes as well as otolith function associated with aging. We found that individuals with impaired horizontal and superior semicircular canal function also were likely to have concomitant deficits in utricular but not saccular function. Overall, we noted that the prevalence of semicircular canal dysfunction was highest followed by saccular then utricular impairment, although we did observe individuals with isolated otolith deficits.

CONCLUSION

These data suggest an overall decline in semicircular canal as well as otolith function associated with aging, although the magnitude of impairment was greater for the semicircular canals than the otoliths in this elderly population. A better understanding of the specific vestibular deficits that occur with aging can inform the development of rational screening, vestibular rehabilitation, and fall risk reduction strategies in older individuals.

[Recording cervical and ocular vestibular evoked myogenic potentials. Part 2: influencing factors, evaluation of findings and clinical significance]

VEMP measurements are subject to various influencing factors: patient age, threshold, sound intensity and frequency. Using air (AC) and bone conduction (BC) the vestibular receptors and afferents of the otolith organs can be activated to varying degrees. Recordings of cervical (cVEMP) and ocular VEMP (oVEMP) are clinically possible. AC-cVEMP are primarily an indicator of the sacculocollic reflex pathway. Together with findings on the vestibuloocular reflex (VOR) and complimentary otolith tests, VEMP enable otolith function analysis of each side separately. In addition, the distinction between combined or isolated canal and otolith dysfunction in terms of subtyping and patterns of damage in mono- and bilateral disorders, such as vestibular neuritis or bilateral vestibulopathy, is possible. Moreover, VEMP is relevant in terms of prognostic and therapeutic considerations as well as expert assessments.

Age-related changes in vestibular evoked myogenic potentials using a modified blood pressure manometer feedback method

PURPOSE

To collect age-specific vestibular evoked myogenic potential (VEMP) data and to characterize age-related differences in VEMP parameters using a modified blood pressure manometer (BPM) method of sternocleidomastoid (SCM) muscle monitoring.

METHODS

VEMPs were recorded on healthy adults ranging in age from 23 to 84 years with no history of dizziness, neuromuscular pathologies, or cervical complaints. Participants were assigned to 3 groups using a nonprobability static group assignment based on their age. VEMP P1 and N1 latency, threshold, peak-to-peak amplitude, and interamplitude difference (IAD) ratios were obtained at 130 dB SPL.

RESULTS

Statistical differences were detected in peak-to-peak mean amplitude and threshold measures among groups. Post hoc analysis revealed that differences shown were between the young group and both older groups. No significant differences were noted in P1 and N1 latencies or IAD ratios.

CONCLUSIONS

This study confirmed a significant decline in VEMP amplitude and increase in VEMP thresholds in healthy older persons. Normative age-related data may be necessary to properly interpret VEMP recordings in a clinical setting when evaluating aging populations. The BPM method utilized for controlling SCM muscle may be a valuable alternative to control SCM muscle contraction when electromyography equipment is not available.

Vestibular evoked myogenic potentials: review

Background:

Disorders of balance often pose a diagnostic conundrum for clinicians, and a multitude of investigations have emerged over the years. Vestibular evoked myogenic potential testing is a diagnostic tool which can be used to assess vestibular function. Over recent years, extensive study has begun to establish a broader clinical role for vestibular evoked myogenic potential testing.

Objectives:

To provide an overview of vestibular evoked myogenic potential testing, and to present the evidence for its clinical application.

Review type:

Structured literature search according to evidence-based medicine guidelines, performed between November 2008 and April 2009. No restrictions were applied to the dates searched.

Conclusion:

The benefits of vestibular evoked myogenic potential testing have already been established as regards the diagnosis and monitoring of several clinical conditions. Researchers continue to delve deeper into potential new clinical applications, with early results suggesting promising future developments.

The effect of age on the sinusoidal harmonic acceleration test, pseudorandom rotation test, velocity step test, caloric test, and vestibular-evoked myogenic potential test

OBJECTIVES

Age-related anatomical and morphologic vestibular deterioration has already been elaborated. Demonstrating a corresponding degradation in physiologic function, however, entails a much higher challenge. The objective of this study was to investigate age-related changes using rotational tests, caloric tests, and the vestibular-evoked myogenic potentials (VEMP) test.

DESIGN

Eighty healthy human subjects (38 men and 42 women) ranging in age from 18 to 80 yrs participated in this study and were subjected to an extensive vestibular test battery. Function tests included sinusoidal harmonic acceleration tests, a pseudorandom rotation test, velocity step tests, a caloric test, and a VEMP test.

RESULTS

No significant age trends were noted for the sinusoidal harmonic acceleration test and velocity step tests response parameters, in contrast to subtle decreasing gain values with advancing age for the pseudorandom rotation test. Increasing slow-component velocity values were measured with the caloric test, whereas the frequency parameter showed no relevant age changes. The largest age trends were detected with the VEMP, with decreasing amplitudes, increasing thresholds, and decreasing N1 latencies. All asymmetry parameters remained stable across the different age categories.

CONCLUSIONS

Only subtle age changes could be demonstrated with the rotational and caloric tests, in contrast to more pronounced age trends with the VEMP.