Aging Effect on Vestibular Evoked Myogenic Potential

The Top 100 Cited Articles in Otology and Neurotology and Analysis of Female Authorship

INTRODUCTION

Despite the increasing number of female trainees in otology and neurotology, women remain underreported in academic medicine. This gender disparity persists in high-impact research, where women are less represented as first and corresponding authors.

METHODS

The top 100 most-cited articles from Otology & Neurotology (1980-2024) were identified using total citation counts. First and corresponding author gender was determined, and trends in female authorship were analyzed over time.

RESULTS

A total of 7,485 Otology & Neurotology articles published between 1980 and 2024 were reviewed and the top 100 cited studies (1.3%) were identified. Women accounted for 29% of first authors and 23% of corresponding authors, with a significant increase in female authorship over time. However, overall representation remains disproportionately low.

DISCUSSION

Our study highlights the persistent underrepresentation of women in otology and neurotology research, despite their growing presence in medicine. Additional efforts are needed to promote greater inclusivity in academic literature of otology and neurotology.

Effects of Age on the Bone-Conduction Amplitude-Modulated cVEMP Temporal Modulation Transfer Function

OBJECTIVES

Cervical vestibular evoked myogenic potentials (cVEMPs) reflect saccular stimulation that results in an inhibitory muscle reflex recorded over the sternocleidomastoid muscle. These responses are utilized to study basic vestibular functions and are also applied clinically. Traditionally, cVEMPs have utilized transient stimuli such as clicks and tonebursts to evoke onset responses. Recently, amplitude-modulated tones have been used to elicit cVEMPs (AMcVEMPs). These AMcVEMP responses can provide information about the magnitude, phase synchrony, and nonlinearities from the vestibulo-collic reflexes that cannot be captured using other existing testing techniques. Although temporal modulation transfer functions (TMTFs) of AMcVEMPs for young, healthy adults have been established using different analysis techniques, there is currently no information regarding the effects of age on these responses. Thus, the current study aimed to examine the effects of age on AMcVEMPs across a broad range of modulation frequencies (MFs) using various AMcVEMP metrics including amplitude, signal to noise ratio (SNR), and phase coherence (PC).

DESIGN

The study included 16 (aged 20 to 39 years) young, 17 (aged 40 to 59 years) mid-age, and 16 (60 to 75 years) older adults with no history of neurological, vestibular, or middle-ear complaints. The stimuli consisted of amplitude-modulated tones with a carrier frequency of 500 Hz and 10 MFs ranging from 11 to 397 Hz. These stimuli were presented using a B81 transducer at 123 dB FL. AMcVEMPs were recorded from the sternocleidomastoid muscle (ipsilateral to the stimulating mastoid) using surface electrodes. Response analysis was performed using an FFT-based approach with analyses including amplitude, SNR, and PC.

RESULTS

AMcVEMP waveforms exhibited periodicity corresponding to the stimulus MF, consistent with previous observations. Furthermore, significant age-related degradation in AMcVEMP amplitude, SNR, and PC measures were observed across a broad range of MFs. While AMcVEMPs were elicited across a wide range of MFs (11 to 263 Hz) for young adults, in mid-age and older adults, these metrics were robust only across a narrower range of MFs, resulting in a reduced TMTF. In addition, the MF eliciting the most robust AMcVEMP varied across different AMcVEMP analysis metrics and age groups.

CONCLUSIONS

A significant decline in the AMcVEMP response is seen as an effect of aging; however, the effect of aging is not uniform across measures or across MFs. The TMTF of AMcVEMP gets flatter, and the overall range is reduced as an effect of aging. Results from this study enhance our understanding of age-related changes in the vestibular system. Expansion of AMcVEMP to clinical populations may lead to a deeper understanding of the pathophysiology of vestibular disorders.

Correlating Migrainous Features With Vestibular-Evoked Myogenic Potentials in Vestibular Migraine

OBJECTIVE

This study aimed to find biomarkers for assessing migrainous features, that is, migrainous headache, sensitivity to sound and light (phono- and photophobia) and visual aura in vestibular migraine (VM) patients.

DESIGN

A retrospective cohort study.

SETTING

University hospital.

PARTICIPANTS

A total of 400 definitive VM patients were classified into four groups based on the number of migrainous features. Group A (n = 45) had one migrainous feature (migrainous headache). Group B (n = 70) had migrainous headache along with phono- and photophobia, while Group C (n = 55) had migrainous headache and visual aura. Those with all three migrainous features were categorised in Group D (n = 230). Another 40 healthy subjects were also enrolled for comparison.

MAIN OUTCOMES MEASURE

All subjects underwent an inner ear test battery comprising audiometry, cervical, ocular vestibular-evoked myogenic potential (cVEMP, oVEMP) and caloric tests.

RESULTS

Significant difference in mean age was observed in Group A when compared to Groups B-D, indicating that younger age might not be associated with the manifestation of all three migrainous features. No significant difference was observed among the four groups irrespective of gender and inner ear test battery. Via multivariate logistic regression, the oVEMP test (adjusted odds ratio, aOR = 2.60) was superior to the cVEMP test as a stronger indicator for the presence of phono- and photophobia. Conversely, the cVEMP test (aOR = 2.59) served as a stronger indicator for the presence of visual aura than the oVEMP test.

CONCLUSION

The oVEMP test may act as a biomarker for phono- and photophobia, whereas the cVEMP test shows a strong capacity to predict visual aura.

[Modified neuronal processing of oVEMPs in patients with multiple sclerosis]

Multiple sclerosis (MS) is an disease of the central nervous system, which is reflected in impaired transmission of impulses due to damage to the myelin layer. In addition to the visual evoked potentials, the vestibular evoked myogenic potentials (VEMPs) are increasingly considered for diagnosis. Due to a low signal-to-noise ratio, several hundred stimulus responses are usually averaged in order to determine the amplitude and latencies from these curves. However, this averaging procedure also filters out information that, if taken into account, could provide further insights into the course of the disease.16 young patients with MS and an EDSS score of 1.4 ± 0.6 were compared with 92 healthy subjects of the same age. Amplitude, latency, AR and five new parameters from the analysis were used as parameters from the tactile evoked oVEMPs.The total n10 amplitude and the n10 amplitude on the left side showed relevant differences tough not reaching statistical significance. In contrast, the n10 amplitude on the right side and the LSD parameter were not significantly different. All n10 latencies and the AR as well as all parameters from the novelty analysis were significantly different.On the one hand, the present study confirms already known changes in the registration of oVEMPs in patients with MS compared to healthy subjects and, on the other hand, the new parameters have the potential to better describe the current state of the disease and to provide detailed information about the current state of myelination or the site of pathophysiological processes within the CNS.

Thirty years with cervical vestibular myogenic potentials: a critical review on its origin

Myogenic potentials generated by acoustic stimulation of the vestibular system have been reported since 1964. This examination became better known as cervical vestibular evoked myogenic potentials (cVEMPs) and gained increasing clinical application since the nineties. Since its discovery, the saccule has been conceived as the most likely vestibular end-organ driving these myogenic potentials of the neck. As findings from both animal and human studies for a long time uniformly provided evidence supporting this theory, cVEMP assessment has become synonymous with evaluation of saccular and inferior vestibular nerve function. This review of the basic evidence supporting this conclusion, questions if cVEMP may be considered as being predominantly or even exclusively driven by the activation of any single vestibular end-organ. We conclude that the results of this review show that contributions from the crista ampullaris of all three ipsilateral semicircular canals, as well as the ipsilateral utricle cannot be ruled out in clinically conducted cVEMP assessments.

Clinical usefulness of vestibular-evoked myogenic potential testing - A review

It has been three decades since the development of vestibular-evoked myogenic potential (VEMP) test. Now is an opportune moment to review clinical usefulness of the VEMP testing in audiovestibular disorders. This review was developed from peer-reviewed articles published in those journals listed on Journal Citation Reports. Initially, 2323 articles were retrieved from 1992 to 2023. Following the guidelines (PRISMA 2020 statement) for reporting reviews, 71 relevant papers were ultimately selected. In conclusion, the integration of acoustic, vibratory, and galvanic stimuli in eliciting cervical VEMP (cVEMP) and ocular VEMP (oVEMP) provides a more thorough identification of the lesion site. When combined with audiometry and caloric testing, the inner ear test battery is highly effective in precisely identifying the affected area, evaluating residual function, and predicting the outcomes of audiovestibular disorders. Furthermore, both cVEMP and oVEMP tests help elucidate the mechanism of audiovestibular disorders, indicating an evolving understanding in this field.

Decoding Age-Linked Masseter Vestibular Evoked Myogenic Potential Changes in Healthy, Aging Individuals

PURPOSE

The primary objective of this study was to assess how age influences masseter vestibular evoked myogenic potential (mVEMP) parameters by utilizing 500-Hz tone burst stimuli delivered through air conduction.

METHOD

The study involved 110 participants ranging from 15 to 60 years of age, grouped into five categories, all of whom had no previous issues related to their vestibular system. The participants were exposed to 500-Hz tone burst stimuli at 125 dB SPL through ER-3A inserts. These stimuli were presented to one ear at a time, with alternating polarity. A Tukey's honestly significant difference test was conducted to compare rectified and unrectified amplitude, along with latencies (P11 and N21) and the asymmetric ratio across all age groups. Additionally, a multivariate analysis of variance was performed to assess the impact of sex on the study variables.

RESULTS

All 110 participants (220 ears) in the study provided mVEMP responses, encompassing 100% of the subjects. The results revealed a significant reduction in both amplitude and latency extension for the P11 and N21 peaks. Interestingly, P11 latency was also prolonged in the youngest participants (Group 1), suggesting ongoing maturation of the system even beyond the age of 16 years. Moreover, a significant sex difference was observed in the P11 latencies. However, there were no substantial sex differences (p > .05) in N1 peak latency, peak-to-peak amplitude, rectified amplitude, and asymmetric ratio.

CONCLUSIONS

Changes in structure occur due to degeneration, and the quantity of vestibular sensory hair cells gradually diminishes with age. The rate of decline is faster in semicircular canals compared to end organs, as observed by Merchant et al. (2000). Following a linear degeneration starting at the age of 40 years, a continuous reduction in sensory cells and primary neurons takes place until approximately 40% of vestibular sensory cells are lost by the age of 75 years and insufficient maturation can lead to prolonged peaks and reduced amplitudes compared with those that are considered normal. Therefore, it is crucial to consider the age of the participants when making diagnoses and incorporate relevant correction factors based on age-related reference data.

High-Frequency Vestibular Function Is Vulnerable to Presbyvestibulopathy

INTRODUCTION

In 2019, mild vestibular function deficiency in elder populations was defined as presbyvestibulopathy (PVP) by the Classification Committee of the Bárány Society. The diagnostic criteria include tests for low-, mid-, and high-frequency vestibular function, represented by caloric testing, rotary chair testing, and head impulse testing, respectively. However, there is still a lack of large-scale reports supporting the relationship between vestibular function tests (VFTs) and aging. In this study, we evaluated whether each test is correlated with aging in the elderly population aged over 50.

METHODS

This study retrospectively enrolled 1043 subjects from a single university hospital database after excluding those with unilateral and bilateral vestibulopathy, central dizziness, and acute dizziness. Enrolled subjects had caloric canal paresis <20%, vHIT lateral canal gain >0.6, vHIT interaural difference <0.3, and age >50 years old.

RESULTS

Significant negative correlations with age were identified in the vHIT (p < 0.001) and rotary chair test (RCT) 1.0 Hz gain (p = 0.030). However, the caloric test (p = 0.739 and 0.745 on the left and right sides, respectively) and RCT 0.12 Hz gain (p = 0.298) did not show a significant correlation with age. A total of 4.83% of subjects aged 70 years or older showed sub-normal vHIT gain that met the criteria of PVP, whereas only 0.50% of subjects aged 60 to 69 did. The prevalence of sub-normal caloric test results, however, was not significantly different between the two age groups (21.55% in the 60-69 age group and 26.59% in the >70 age group).

CONCLUSIONS

The high-frequency range vestibular function seems vulnerable to aging, and this is more discernible at age >70 years. The weak correlation between age and low-frequency vestibular function tests, such as the caloric test and low-frequency rotary chair testing, suggests the need to revisit the diagnostic criteria for PVP.

Vestibular evoked myogenic potential (VEMP) test-retest reliability in adults

BACKGROUND

The technique of measuring ocular vestibular evoked myogenic potentials (oVEMP) in response to Mini-shaker vibration is relatively new, there is a limited normative data to define the presence or absence of a response in the literature.

OBJECTIVE

To determine the test-retest reliability of cervical and ocular VEMPs (cVEMP and oVEMP, respectively) to air-conducted sound (ACS) and bone-conducted vibration (BCV) stimulation and to determine normative ranges for the responses.

METHODS

Twenty normal-hearing individuals (40 ears) and 20 hearing impaired volunteers with normal balance function (40 ears) were examined in this study. ACS cVEMP and BCV oVEMP (using a Mini-shaker) were recorded from both groups to assess the test-retest reliability and to collect normative VEMP data for P1/N1 latencies and amplitudes from 20 normal hearing individuals. To test reliability, VEMP recordings were repeated within the same session.

RESULTS

The test-retest reliability for all the cVEMP parameters showed excellent reliability whereas oVEMP parameters showed between fair and excellent reliability depending on the parameter tested. Normative data for VEMP P1/N1 latencies and amplitudes were established.

CONCLUSIONS

Normative data and test-retest reliability for BCV oVEMP using the Mini-shaker at 100 Hz were established in our study for the first time in the literature. Responses appear reliable.

Vestibular Tests Related to Tumor Volume in 137 Patients With Small to Medium-Sized Vestibular Schwannoma

OBJECTIVE

The video head impulse test (vHIT) and cervical and ocular vestibular evoked myogenic potentials (cVEMP and oVEMP) are new methods for measuring peripheral vestibular function. The objectives of this study were to compare these tests and the traditionally used caloric test in patients with small and medium-sized untreated vestibular schwannoma (VS) and to measure the correlation between the tests' results and tumor volume.

STUDY DESIGN

National cross-sectional study.

SETTING

Tertiary university clinic.

METHODS

Prevalence of abnormal cVEMP, oVEMP, caloric test, and 6-canal vHIT results on the tumor side and the nontumor side were compared and related to tumor volume with regression analyses in 137 consecutive VS patients assigned to a wait-and-scan protocol in the period 2017 to 2019.

RESULTS

The sensitivity of 6-canal vHIT, caloric test, cVEMP, and oVEMP to detect vestibulopathy in VS patients was 51%, 47%, 39%, and 25%, respectively. Normal tests were found in 21% of the patients. The results of vHIT and caloric test were related to tumor volume, but this was not found for cVEMP and oVEMP.

CONCLUSION

The caloric test and 6-canal vHIT showed the highest sensitivity in detecting vestibulopathy in untreated VS patients. vHIT, and particularly the posterior canal, was limited with a high prevalence of abnormal results on the nontumor side. A combination of cVEMP and caloric test was favorable in terms of a relatively high sensitivity and low prevalence of abnormal results on the nontumor side. Larger tumors had a higher rate of pathology on caloric testing and vHIT.

Effectiveness of the aquatic physical therapy exercises to improve balance, gait, quality of life and reduce fall-related outcomes in healthy community-dwelling older adults: A systematic review and meta-analysis

BACKGROUND

Opting to use aquatic or land-based physical therapy exercises to improve balance, gait, quality of life and reduce fall-related outcomes in community-dwelling older adults (CDOAs) is still a questionable clinical decision for physiotherapists.

OBJECTIVE

Assess the quality of evidence from randomized or quasi-randomized controlled trials that used aquatic physical therapy exercises to improve balance, gait, quality of life and reduce fall-related outcomes in CDOAs.

METHODS

Articles were surveyed in the following databases: MEDLINE/PubMed, EMBASE, SCOPUS, LILACS, Web of Science, CENTRAL (Cochrane Central Register of Controlled Trials), PEDro, CINAHL, SciELO and Google Scholar, published in any language, up to July 31, 2023. Two independent reviewers extracted the data and assessed evidence quality. The risk of bias of the trials was evaluated by the Cochrane tool and evidence quality by GRADE approach. Review Manager software was used to conduct the meta-analyses.

RESULTS

3007 articles were identified in the searches, remaining 33 studies to be read in full, with 11 trials being eligible for this systematic review. The trials included presented low evidence quality for the balance, gait, quality of life and fear of falling. Land-based and aquatic physical therapy exercises improved the outcomes analyzed; however, aquatic physical therapy exercises were more effective in improving balance, gait, quality of life and reducing fear of falling in CDOAs. The meta-analysis showed that engaging in aquatic physical therapy exercises increases the functional reach, through of the anterior displacement of the center of pressure of CDOAs by 6.36cm, compared to land-based physical therapy exercises, assessed by the Functional Reach test: [CI:5.22 to 7.50], (p<0.00001), presenting low quality evidence.

CONCLUSIONS

Aquatic physical therapy exercises are more effective than their land-based counterparts in enhancing balance, gait, quality of life and reducing the fear of falling in CDOAs. However, due to methodological limitations of the trials, this clinical decision remains inconclusive. It is suggested that new trials be conducted with greater methodological rigor, in order to provide high-quality evidence on the use of the aquatic physical therapy exercises to improve the outcomes analyzed in CDOAs.

Establishing cervical vestibular evoked myogenic potential (cVEMP) normative data in Singapore school-aged children

OBJECTIVES

The Cervical Vestibular Evoked Myogenic Potential (cVEMP) is often employed in routine clinical practice as part of the vestibular test battery assessments. However, there is currently no well-established paediatric cVEMP normative data in Singapore. Additionally, limited literature has examined the relationship between neck length and cVEMP parameters. The main aims of this study are to 1) establish cVEMP normative data from Singaporean school-aged children aged 6-12 years old, and 2) examine if there is a significant correlation between neck length and cVEMP parameters.

METHODS

31 healthy children participated in this study. Every participant was screened to ensure that they had normal auditory and vestibular profiles before completing the cVEMP procedure, which involved 500 Hz tone burst through insertphones and head elevation from supine position as the method of neck contraction.

RESULTS

The response rate in 62 ears was 98.4% at 95 dBnHL and 100% at 100 dBnHL. The mean P1 and N1 latencies were 13.96 ± 1.17 m s and 21.50 ± 1.66 m s, with a mean corrected P1-N1 amplitude of 0.88 ± 0.34, and mean asymmetry ratio of 13 ± 10%. Median threshold was 80 dBnHL. Significant positive correlation between neck length and both P1, N1 latencies, and significant negative correlation between neck length and corrected P1-N1 amplitude were observed.

CONCLUSIONS

cVEMP paediatric normative data has been established for Singaporean school-aged children. The study also confirmed that neck length did have a significant influence on both latencies and corrected amplitude.

Comprehensive Normative Data for Objective Vestibular Tests

INTRODUCTION

 Vestibular dysfunction is a debilitating disorder frequently encountered in neurological and otological settings. The vestibular system is a complex network between peripheral and central mechanisms. This innate complexity of the vestibular system necessitates objective test procedures for evidence-based diagnostic formulations and intervention. Objective tests aid in the evaluation of both peripheral and central vestibular pathologies. Establishing and availability of comprehensive normative data for these objective tests is crucial for clinicians and researchers alike.

MATERIALS AND METHODS

This is a prospective study involving 120 participants (both males and females) aged between 18 and 55 years. All participants were right-handed individuals and had no significant medical history. On pre-set protocols, cVEMP (cervical vestibular evoked myogenic potential), oVEMP (ocular vestibular evoked myogenic potential), vHIT (video head impulse test), and VNG (videonystagmography) were done.

RESULTS

While all participants (n=120) underwent cVEMP, oVEMP, vHIT, saccade, smooth pursuit, and optokinetic tests, only 109 participants consented to the caloric test. Each test's mean, standard deviation, median, quartile, and third quartiles have been recorded. A right-left comparison yielded no significant difference on cVEMP, oVEMP, caloric test, smooth pursuit, and optokinetic test. However, few vHIT and saccade parameters did reveal significant differences.

DISCUSSION

This study presents comprehensive normative data for cVEMP, oVEMP, vHIT, caloric test on VNG, and oculomotor tests (smooth pursuit, saccade, optokinetic) on VNG. The test results were in concordance with previously published data. The significant difference between the right and left sides in vHIT may be because of the monocular goggles used for the testing.

CONCLUSION

This study brings out the normative data for various vestibular tests on individuals aged between 18-55 years. This information could aid both clinicians and researchers working in the field of vestibular science.

Normative and Pathological Ranges of Cervical Vestibular Evoked Myogenic Potentials in Normal Subjects and Patients with Complete Compensated Unilateral Vestibular Loss: A Cross Sectional Study

To know the normative ranges of VEMP response metrics in healthy young adults. To know the pathological cutoff of VEMP metrics in unilateral vestibular loss patients. To compare our VEMP metrics with the normative values of other studies from the western world. Prospective cross-sectional study. Tertiary care audiovestibular laboratory. 30 healthy subjects and 15 cases with a unilateral complete compensated loss. Various VEMP parameters-p1 latency, n1 latency, p1-n1 amplitude and Interaural asymmetry ratio (IAR) were entered into databases and analyzed. We compared our parameters with the most cited scientific data on VEMP available in the PubMed database, and we analyzed the results. 90% of controls and 80% of cases got VEMP responses at 95 dB HL threshold, 500 Hz with subject/patient placed in sitting upright with head turned to opposite side position. The normative data of VEMP response metrics in young adults for p1, n1 latencies, p1-n1 amplitude, and IAR are 13 ± 2 ms, 21 ± 2 ms, 91 ± 33 uV, and 9.25 ± 7.3, respectively. As the VEMP test has 100% sensitivity and 100% (95% CI 87-100%) negative predictive value in detecting the saccular dysfunction, we recommend the VEMP test as a mandatory tool in the vestibular test battery. There is no statistically significant difference in various VEMP parameters between the control and normal sides of the case group.

Cervical vestibular evoked myogenic potentials in 3-month-old infants: Comparative characteristics and feasibility for infant vestibular screening

Objective

We compared the characteristics of air-conducted sound cervical vestibular evoked myogenic potential (ACS-cVEMP) and bone-conducted vibration cVEMP (BCV-cVEMP) among 3-month-old infants with normal hearing and sensorineural hearing loss (SNHL), and healthy adults to explore the feasibility and optimal strategies for infant vestibular screening.

Methods

29 infants (58 ears) were divided into two groups according to hearing (group I: normal hearing ears; group II: SNHL ears), 20 healthy adults were defined as group III. The results of response rate, P13 and N23 latency, P13-N23 interval, amplitudes, and corrected interaural asymmetry ratio (IAR) were recorded and compared among three groups.

Results

The response rates of ACS-cVEMP in three groups were 88.89, 62.00, 100%, respectively. The P13 and N23 latencies, and P13-N23 interval did not differ significantly between group I and II (p = 0.866, p = 0.190, p = 0.252). A significant difference was found between group I and III (p = 0.016, p &lt; 0.001, p &lt; 0.001). No significant difference was observed in raw or corrected amplitude between group I and II (p = 0.741, p = 0.525), while raw and corrected amplitudes in group III were significantly larger than group I (p &lt; 0.001, p &lt; 0.001). For BCV-cVEMP, the response rates in three groups were 100, 86.36, 100%, respectively, No significant difference existed in the P13 and N23 latency, or P13-N23 interval between group I and II (p = 0.665, p = 0.925, p = 0.806), however, P13 and N23 latencies were significantly longer in group III than group I (p &lt; 0.001, p = 0.018), but not in P13-N23 interval (p = 0.110). There was no significant difference in raw or corrected amplitude between group I and II (p = 0.771, p = 0.155) or in raw amplitude between group I and III (p = 0.093), however, a significant difference existed in corrected amplitude between group I and III (p &lt; 0.001).

Conclusions

Compared with adults, 3-month-old infants with normal hearing presented with equivalent response rates, shorter P13 and N23 latencies, smaller corrected amplitudes, and a wider IAR range for both ACS and BCV-cVEMP. SNHL infants had equivalent response rates of BCV-cVEMP, lower response rates of ACS-cVEMP than normal hearing infants. When responses were present, characteristics of ACS and BCV-cVEMP in SNHL infants were similar with normal hearing infants. ACS combined with BCV-cVEMP are recommended to improve the accuracy of vestibular screening.

B81 Bone Vibrator-Induced Vestibular-Evoked Myogenic Potentials: Normal Values and the Effect of Age

Objective

To define the normal values and examine the influence of aging on B81 bone vibrator-induced cervical vestibular-evoked myogenic potentials (B81-cVEMPs) and ocular vestibular-evoked myogenic potentials (B81-oVEMPs).

Methods

Seventy healthy subjects, divided into seven groups according to their ages, were enrolled in this study. The 4–9-, 10–19-, 20–29-, 30–39-, 40–49-, 50–59-, and 60–70-year-old participants were divided into groups I–VII, respectively. B81-cVEMP and B81-oVEMP were recorded in each group.

Results

The B81-cVEMP response rates for groups I–VII were 100, 100, 100, 100, 95, 95, and 75%, respectively, with significant differences only between groups I–VI and group VII (p = 0.047, p &lt; 0.05). The B81-oVEMP response rates for groups I–VII were 100, 100, 100, 100, 70, 65, and 40%, respectively, with significant differences only between groups I–IV and groups V–VII (p = 0.020, p = 0.008, p = 0.000; p &lt; 0.05). The threshold, P13, and N23 latencies of B81-cVEMP positively correlated with age (r = 0.756, p = 0.000; r = 0.357, p = 0.003; r = 0.316, p = 0.009; p &lt; 0.05). The raw amplitudes and corrected amplitudes negatively correlated with age (r = −0.641, p = 0.000; r = −0.609, p = 0.000, p &lt; 0.05). For B81-oVEMP, the corrected amplitudes negatively correlated with age (r = −0.638, p = 0.000, p&lt;0.05), but the threshold and N10 latency positively correlated with age (r = 0.768, p = 0.000; r = 0.334, p = 0.009, p &lt; 0.05). Moreover, the interaural asymmetry ratio did not significantly correlate with age for B81-cVEMP and B81-oVEMP.

Conclusion

As age increased, the B81-cVEMP response rate decreased, the thresholds increased, P13 and N23 latencies were prolonged, and the raw amplitude and corrected amplitude decreased. The B81-oVEMP response rate and corrected amplitude decreased, the thresholds increased, and N10 latency was prolonged with age. These changes are probably due to the occurrence of morphological and functional changes in the vestibular system with aging. Therefore, we suggest establishing different reference values according to different age groups when evaluating the VEMP results in patients with vestibular diseases.

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.

Exploring Vestibular Assessment in Patients with Headache and Dizziness

Patients often report symptoms of headache and dizziness concomitantly. Symptoms of dizziness can be explored with a comprehensive vestibular assessment, allowing for the investigation of central and peripheral vestibular system contributions to symptoms of dizziness. Patients who report both symptoms of headache and dizziness demonstrate abnormalities of the vestibular system which can be measured quantitatively. Completion of comprehensive vestibular testing can help to guide diagnosis and strategies for intervention.

Age-related changes to vestibular heave and pitch perception and associations with postural control

Falls are a common cause of injury in older adults (OAs), and age-related declines across the sensory systems are associated with increased falls risk. The vestibular system is particularly important for maintaining balance and supporting safe mobility, and aging has been associated with declines in vestibular end-organ functioning. However, few studies have examined potential age-related differences in vestibular perceptual sensitivities or their association with postural stability. Here we used an adaptive-staircase procedure to measure detection and discrimination thresholds in 19 healthy OAs and 18 healthy younger adults (YAs), by presenting participants with passive heave (linear up-and-down translations) and pitch (forward-backward tilt rotations) movements on a motion-platform in the dark. We also examined participants' postural stability under various standing-balance conditions. Associations among these postural measures and vestibular perceptual thresholds were further examined. Ultimately, OAs showed larger heave and pitch detection thresholds compared to YAs, and larger perceptual thresholds were associated with greater postural sway, but only in OAs. Overall, these results suggest that vestibular perceptual sensitivity declines with older age and that such declines are associated with poorer postural stability. Future studies could consider the potential applicability of these results in the development of screening tools for falls prevention in OAs.

Vestibular Function in Pendred Syndrome: Intact High Frequency VOR and Saccular Hypersensitivity

OBJECTIVE

Although Pendred syndrome involves anatomical abnormalities in the vestibular system and patient-perceived dizziness, the literature on vestibular function is scarce. The objective was to evaluate objective vestibular function in patients with PS using the video head impulse test (VHIT) and the cervical vestibular evoked myogenic potential (cVEMP) test, assessing the high frequency vestibulo-ocular reflex (VOR) and the saccular function, respectively.

METHODS

Twenty-six subjects (52 ears) with Pendred Syndrome and severe-to-profound hearing loss (cochlear implant candidacy) were studied retrospectively. Main outcome measures were VHIT VOR gain, refixation saccades, cVEMP stimulus thresholds and amplitudes.

RESULTS

In total, 4 of 52 ears (8%) had pathological VHIT outcomes (2 ears with low VHIT gain and 2 ears with saccades). The mean VHIT gain value was 0.96 (range 0.63-2.02). No patients had complete VOR loss. CVEMP responses were present in 76% of tested ears and absent in 24%. The mean cVEMP amplitude value was 192 μV. Absence of cVEMP response was associated with the presence of VHIT saccades (p = 0.038) and advanced age (rs = -0.34; p < 0.05). cVEMP amplitude was correlated with VHIT gain (rs = 0.46; p < 0.001).

CONCLUSION

Despite dysmorphic vestibular anatomy and severe loss of hearing, the VHIT VOR function is normal in patients with Pendred Syndrome. However, saccular function appears to be abnormally sensitive, as documented by low cVEMP thresholds and high amplitudes, which agrees with a "third window" effect secondary to the large vestibular aqueduct.

Retro-labyrinthine Lesion Site Detected by Galvanic Vestibular Stimulation Elicited Vestibular-evoked Myogenic Potentials in Patients with Auditory Neuropathy

OBJECTIVE

Auditory neuropathy (AN) is a unique pattern of hearing loss with preservation of hair cell function. The condition is characterized by the presence of otoacoustic emissions (OAE) or cochlear microphonic (CM) responses with severe abnormalities of the auditory brainstem response (ABR). The vestibular branches of the VIII cranial nerve and the structures innervated by it can also be affected. However, the precise lesion sites in the vestibular system are not well characterized in patients with AN.

METHODS

The air-conducted sound (ACS) vestibular-evoked myogenic potentials (VEMPs) and galvanic vestibular stimuli (GVS)-VEMPs were examined in 14 patients with AN.

RESULTS

On examination of VEMPs (n=14, 28 ears), the absent rates of ACS-cervical VEMP (cVEMP), ACS-ocular VEMP (oVEMP), GVS-cVEMP, GVS-oVEMP and caloric test were 92.9% (26/28), 85.7% (24/28), 67.9% (19/28), 53.6% (15/28), and 61.5% (8/13), respectively. Impaired functions of the saccule, inferior vestibular nerve, utricle, superior vestibular nerve, and horizontal semicircular canal were found in 25.0% (7/28), 67.9% (19/28), 32.1% (9/28), 53.6% (15/28) and 61.5% (8/13) patients, respectively. On comparing the elicited VEMPs parameters of AN patients with those of normal controls, both ACS-VEMPs and GVS-VEMPs showed abnormal results in AN patients (such as, lower presence rates, elevated thresholds, prolonged latencies, and decreased amplitudes).

CONCLUSION

The study suggested that patients with AN often have concomitant vestibular disorders. Retro-labyrinthine lesions were more frequently observed in this study. GVS-VEMPs combined with ACS-VEMPs may help identify the lesion sites and facilitate detection of areas of vestibular dysfunction in these patients.

Effects on cervical vestibular-evoked myogenic potentials of four clinically used head and neck measurement positions in healthy subjects

BACKGROUND

The most reliable head and neck position for cervical vestibular-evoked myogenic potentials (cVEMPs) measurements yet to be determined.

AIMS/OBJECTIVES

To assess how four body positions used during clinical recordings of cVEMPs affect cVEMP parameters.

MATERIAL AND METHOD

cVEMPs of 10 healthy subjects (26-50 years old) were recorded in four body positions: A. sitting/head rotated; B. supine/head rotated; C. semi-recumbent/head rotated and elevated; D. supine/head elevated.

RESULTS

Mean background sternocleidomastoid muscle (SCM) electrical activity was significantly higher in positions C and D than in positions A and B. The latencies of p13 and n23 differed significantly among the four positions. Raw p13-n23 complex amplitude was significantly greater in positions C and D than in A and B. These differences were reduced when amplitudes were corrected by SCM activity. For positions A and B, one and two subjects, respectively, had an abnormal raw asymmetry ratio (AR). After correction, all subjects had normal ARs in all positions.

CONCLUSIONS AND SIGNIFICANCE

Body positions in which the head is elevated produce a quicker and larger cVEMP response compared to positions in which the head is not elevated. The difference in ARs among positions can be ignored as long as the correction is made.

Response characteristics of vestibular evoked myogenic potentials recorded over splenius capitis in young adults and adolescents

BACKGROUND AND OBJECTIVES

Examine vestibular evoked myogenic potential (VEMP) responses recorded from surface electrodes over Splenius Capitis (SPC) in a seated position.

SPECIFIC AIMS

(1) validate response characteristics of VEMP recordings from surface electrodes over Sternocleidomastoid (SCM) and over SCP and (2) assess age effects on responses in adolescents and young adults.

MATERIALS AND METHODS

Simultaneous surface VEMP was recorded bilaterally from electrodes placed over the dorsal neck musculature at a location known from previous work to record from SPC in 15 healthy participants during trials with head rotation toward and away from the stimulated ear. VEMP was also recorded from electrodes over SCM, ipsilateral to the stimulus ear, in the same participants in a supine, head lift/turn position.

RESULTS

Response amplitudes significantly increased with contraction strength and decreased with age. Participants were able to maintain sufficient contraction strength (amplitude) with head rotation to reliably measure over SPC. Normalized response amplitudes measured from electrodes over contralateral SPC were largest with head rotation contralateral to the stimulus ear. Normalized amplitudes and peak latencies were comparable to the same measures from SCM obtained in supine, head lift/turn position.

CONCLUSIONS

Otolith generated myogenic responses can be recorded seated from electrodes over the dorsal neck with head rotation contralateral to the stimulus ear. In this position, contralateral recordings are consistent with responses known from previous work to arise from SPC; ipsilateral recordings may include crosstalk from activated muscles nearby, including ipsilateral SCM. Overall, techniques targeting contralateral SPC during contralateral head turn may provide additional methods of recording VEMPs.

Normal values for cervical and ocular vestibular-evoked myogenic potentials using EMG scaling: effect of body position and electrode montage

BACKGROUND

The clinical utility of cervical and ocular vestibular-evoked myogenic potential (cVEMP and oVEMP) is limited by variability of testing protocols and a dearth of normative data using contemporary methods for amplitude scaling.

AIMS/OBJECTIVES

To investigate the effect of body position and electrode montage on VEMP responses and to establish normative values.

MATERIAL AND METHODS

This is a repeated measures study of 44 healthy young adult subjects (22 men and 22 women).

RESULTS

The highest response rate (99%) for cVEMP was achieved in the supine position with the head elevated and turned. For oVEMP, the highest response rate (90%) was achieved using nasal alar electrode montage with the subject in a sitting position. Scaled peak-to-peak amplitude was higher in males than in females for both cVEMP and oVEMP.

CONCLUSION

Normative data for 44 young healthy adults was successfully collected for two body positions for cVEMP and two head positions and two electrode montages for oVEMP.

SIGNIFICANCE

Our findings describe VEMP protocols that efficiently detect VEMP responses, and we provide normative VEMP response data for young healthy subjects. We describe a potential difference in response between males and females, which may be clinically important.

Angular vestibulo ocular reflex loss with preserved saccular function in Machado-Joseph disease

OBJECTIVE

To provide a comprehensive evaluation of the vestibular function in Machado-Joseph Disease (MJD).

METHODS

21 MJD patients and 19 healthy Controls underwent a detailed clinical neuro-otological evaluation including VOR gain of all six semicircular canals by video Head Impulse Test (vHIT), remaining horizontal VOR function by Suppression Head Impulse test (SHIMP), and saccular function by cervical Vestibular Evoked Myogenic Potentials (cVEMP).

RESULTS

All MJD had significantly lower VOR gain in all six semicircular canals (p < 0.001) with a mean ± SEM of horizontal gain of 0.52 ± 0.04 and vertical gain of 0.57 ± 0.03 versus Controls' gain of 0.95 ± 0.01 and 0.81 ± 0.02, respectively (p < 0.001). MJD showed also a significantly lower VOR gain on the SHIMP test with left gain of 0.51 ± 0.04 and right gain of 0.46 ± 0.03 versus Controls' gain of 0.79 ± 0.01 and 0.83 ± 0.03, respectively (p < 0.001). In contrast, MJD had normal saccular function reflected by the presence of cVEMP response in 18/20 patients and in 12/17 of Controls, with a non-significant difference between MJD and Controls of P13 and N23 peaks latency and normalized peak-to-peak amplitude. ROC analysis of horizontal VOR gain resulted in an area under the curve of 0.993 making the average lateral canals' VOR gain an excellent classifier of MJD vs Controls.

CONCLUSIONS

Horizontal and vertical VOR impairment with preserved sacculo-collic function seems to be a distinctive feature of MJD and could be explained by selective, mostly medial and superior vestibular nuclei degeneration. This study further supports the idea that horizontal VOR gain measured by vHIT could be a potential neurophysiological biomarker of MJD.

Vestibular Neuritis in Patients Among Different Age Groups: Clinical Features and Outcomes

BACKGROUND

Patients with vestibular neuritis (VN) displayed differential prognosis despite of the same treatment. Thus, identifying unique characteristics in different populations and creating individually customized treatments are necessary. However, studies about the clinical features according to different ages are scarce.

PURPOSE

This article compares the differences in VN patients among different age groups.

RESEARCH DESIGN

A prospective study.

STUDY SAMPLE

A total of 70 VN patients were enrolled in the present study.

INTERVENTION

All the patients started vestibular rehabilitation at the time of initial presentation to our clinic. They were followed up at 1-month intervals using the questionnaire until 4 months.

DATA COLLECTION AND ANALYSIS

Patients' clinical data including clinical presentation, vestibular testing results, treatment, and recovery was collected and analyzed with Duncan's multiple range test, the sign test, and the Kruskal-Wallis test using SPSS18.0.

RESULTS

The mean age of the 70 patients was 47.2 ± 17.1, ranging from 10 to 76 years old. The sex ratios (male:female) were 3.5 in the adolescent group, 0.643 in the young adult group, 1.375 in the middle-aged group, and 0.583 in the senior group. The prevalence of hypertension and diabetes mellitus showed a significantly increasing trend from young adults to the seniors (p < 0.05). The caloric response was statistically worse in the senior group than the other groups (p < 0.05). The abnormal rates for video head impulse test, vestibular-evoked myogenic potential, and vestibular autorotation test did not differ significantly in different age groups. A significant difference between prerehabilitation and postrehabilitation total Dizziness Handicap Inventory (DHI) scores was identified in all the groups (p < 0.05). The younger patients demonstrated a greater improvement than patients in the senior group, meanwhile adolescents improved the most (p < 0.05). Hospital Anxiety and Depression Scale (HADS) was the lowest in the adolescent group (p < 0.05). DHI score at acute stage was significantly correlated with HADS (r = 0.597, p < 0.05).

CONCLUSION

The canal response was statistically better for younger patients compared with the elderly. The younger patients demonstrated a greater improvement than patients in the senior group, among whom adolescents improved the most, meanwhile psychological factors played a minor role in adolescents. Self-perceived disability-handicap positively correlated with anxiety and depression in all patients.

Functional Integrity of the Inferior Vestibular Nerve and Posterior Canal BPPV

The functional integrity of the inferior vestibular nerve (IVN) may be evaluated by the cervical vestibular evoked myogenic potential (cVEMP) response, which requires signal transmission via the nerve. As functional integrity of the IVN innervating the posterior semicircular canal is required to produce the typical positioning vertigo and nystagmus characterizing posterior canal benign paroxysmal positional vertigo (PCBPPV), we hypothesized that normal cVEMPs would be found in most PCBPPV patients. Twenty-four PCBPPV patients participated in a prospective cohort study. All were treated by canal repositioning maneuver and had air-conduction cVEMP and videonystagmography (VNG). Follow-up evaluations including history and otoneurological bedside examination were carried out 1, 3, 6, and 12 months after the initial treatment. At the last follow-up, the patients filled the Dizziness Handicap Inventory (DHI) questionnaire. Normal cVEMPs were recorded in 19 (79%) and were absent in 5 (21%) of the subjects. The average DHI in the patients with normal cVEMP was 16.42 ± 17.99 vs. 0.4 ± 0.89 among those with pathological cVEMP (p < 0.04, Mann-Whitney test). Thirteen (54%) patients experienced recurrent PCBPPV (rPCBPPV). The average DHI score was significantly higher among patients having recurrence (22.15 ± 18.61) when compared to those with complete cure (2.36 ± 5.98; p < 0.003, Mann-Whitney test). Ten (77%) of the subjects with rPCBPPV had normal and 3 (23%) had pathological cVEMP as compared to 9 (82%) and 2 (18%) subjects in the non-recurrent (nrPCBPPV) group (Fisher's exact test-not significant). cVEMP p13 and n23 wave latencies and amplitudes, inter-aural differences in p13-n23 peak-to-peak amplitudes, and response thresholds did not differ between the groups. No differences were found between the rPCBBPV and nrPCBBPV groups in VNG caloric lateralization and directional preponderance values. We have found that in most cases, PCBPPV symptoms and signs are associated with normal cVEMP response supporting the role of IVN functional integrity. The absent cVEMPs in the minority of patients, although having similar clinical presentation, raise the possibility that the ipsilateral saccule is affected by the same pathology causing degeneration of the utricle macula. Alternatively, lacking inhibitory stimuli from the involved ipsilateral utricle or partial degeneration of the IVN and ganglion could explain the diminished cVEMP response. Clinical Trial Registration: The study was registered in ClinicalTrials.gov Internet site (study ID-NCT01004913; https://clinicaltrials.gov/ct2/show/NCT01004913?cond=BPPV&cntry=IL&draw=2&rank=3).

Ocular Vestibular-Evoked Myogenic Potential Amplitudes Elicited at 4 kHz Optimize Detection of Superior Semicircular Canal Dehiscence

Introduction: High-resolution temporal bone computed tomography (CT) is considered the gold standard for diagnosing superior semicircular canal dehiscence (SCD). However, CT has been shown over-detect SCD and provide results that may not align with patient-reported symptoms. Ocular vestibular-evoked myogenic potentials (oVEMPs)—most commonly conducted at 500 Hz stimulation—are increasingly used to support the diagnosis and management of SCD. Previous research reported that stimulation at higher frequencies such as 4 kHz can have near-perfect sensitivity and specificity in detecting radiographic SCD. With a larger cohort, we seek to understand the sensitivity and specificity of 4 kHz oVEMPs for detecting clinically significant SCD, as well as subgroups of radiographic, symptomatic, and surgical SCD. We also investigate whether assessing the 4 kHz oVEMP n10-p15 amplitude rather than the binary n10 response alone would optimize the detection of SCD.

Methods: We conducted a cross-sectional study of patients who have undergone oVEMP testing at 4 kHz. Using the diagnostic criteria proposed by Ward et al., patients were determined to have SCD if dehiscence was confirmed on temporal bone CT by two reviewers, patient-reported characteristic symptoms, and if they had at least one positive vestibular or audiometric test suggestive of SCD. Receiver operating characteristic (ROC) analysis was conducted to identify the optimal 4 kHz oVEMP amplitude cut-off. Comparison of 4 kHz oVEMP amplitude across radiographic, symptomatic, and surgical SCD subgroups was conducted using the Mann-Whitney U test.

Results: Nine hundred two patients (n, ears = 1,804) underwent 4 kHz oVEMP testing. After evaluating 150 temporal bone CTs, we identified 49 patients (n, ears = 61) who had radiographic SCD. Of those, 33 patients (n, ears = 37) were determined to have clinically significant SCD. For this study cohort, 4 kHz oVEMP responses had a sensitivity of 86.5% and a specificity of 87.8%. ROC analysis demonstrated that accounting for the inter-amplitude of 4 kHz oVEMP was more accurate in detecting SCD than the presence of n10 response alone (AUC 91 vs. 87%). Additionally, using an amplitude cut-off of 15uV reduces false positive results and improves specificity to 96.8%. Assessing 4 kHz oVEMP response across SCD subgroups demonstrated that surgical and symptomatic SCD cases had significantly higher amplitudes, while radiographic SCD cases without characteristic symptoms had similar amplitudes compared to cases without evidence of SCD.

Conclusion: Our results suggest that accounting for 4 kHz oVEMP amplitude can improve detection of SCD compared to the binary presence of n10 response. The 4 kHz oVEMP amplitude cut-off that maximizes sensitivity and specificity for our cohort is 15 uV. Our results also suggest that 4 kHz oVEMP amplitudes align better with symptomatic SCD cases compared to cases in which there is radiographic SCD but no characteristic symptoms.

Bone Conduction Vibration Vestibular Evoked Myogenic Potential (VEMP) Testing: Reliability in Children, Adolescents, and Young Adults

OBJECTIVES

Bone conduction vibration (BCV) vestibular evoked myogenic potentials (VEMP) are clinically desirable in children for multiple reasons. However, no accepted standard exists for stimulus type and the reliability of BCV devices has not been investigated in children. The objective of the current study was to determine which BCV VEMP method (B-71, impulse hammer, or Mini-shaker) yields the highest response rates and reliability in a group of adults, adolescents, and children. It was hypothesized that the Mini-shaker would yield the highest response rates and reliability because it provides frequency specificity, higher output levels without distortion, and the most consistent force output as compared to the impulse hammer and B-71.

DESIGN

Participants included 10 child (ages 5 to 10), 11 adolescent (ages 11 to 18), and 11 young adult (ages 23 to 39) normal controls. Cervical VEMP (cVEMP) and ocular VEMP (oVEMP) were measured in response to suprathreshold air-conducted, 500 Hz tone bursts and 3 types of BCV (B-71, impulse hammer, and Mini-shaker) across 2 test sessions to assess reliability.

RESULTS

For cVEMP, response rates were 100% for all methods in all groups with the exception of the adult group in response to the impulse hammer (95%). For oVEMP, response rates varied by group and BCV method. For cVEMP, reliability was highest in adults using the Mini-shaker, in adolescents using the impulse hammer, and in children using the B-71. For oVEMP, reliability was highest in adults using the Mini-shaker, in adolescents using the Mini-shaker or impulse hammer, and in children using the impulse hammer. Age positively correlated with air-conducted oVEMP amplitude, but not cVEMP amplitude or cVEMP corrected amplitude. Age negatively correlated with all BCV VEMP amplitudes with the exception of cVEMP corrected amplitude in response to the Mini-shaker.

CONCLUSIONS

All BCV methods resulted in consistent cVEMP responses (response rates 95 to 100%) with at least moderate reliability (intraclass correlation coefficient ≥ 0.5) for all groups. Similarly, all BCV methods resulted in consistent oVEMP responses (89 to 100%) with at least moderate reliability (intraclass correlation coefficient ≥ 0.5) except for the B-71 in adults.

Cervical Vestibular Evoked Myogenic Potentials in Benign Paroxysmal Positional Vertigo: A Systematic Review and Meta-Analysis

Objective: The objective of our study was to investigate the potential association between the occurrence of benign paroxysmal positional vertigo (BPPV) and saccular dysfunction using cervical vestibular evoked myogenic potentials (cVEMP) testing. Methods: The databases including Pubmed, Embase, and CENTRAL were systemically searched for case-control literatures investigating saccular dysfunction using cVEMP testing in BPPV patients compared with healthy controls. The literatures were published up to 16 April 2019 and were limited to the English language. All statistical processes were carried out using software Review Manager, version 5.3. Subgroup analysis and sensitive analysis were performed simultaneously. Results: Of the 12 case-control studies confirmed for meta-analysis, p13 latency of cVEMP was assessed in 8 studies, n23 latency in 6 studies, amplitude in 5 studies, asymmetry ratio (AR) in 3 studies, proportion of absent response in 9 studies, and abnormal cVEMP in 8 studies. Compared with healthy controls, the p13 mean latency of cVEMP was longer (MD = 0.88, 95% CI = 0.64-1.12, p < 0.00001), the mean amplitude was lower (SMD = -0.60, 95% CI = -0.80 to -0.41, p < 0.00001), and the proportions of absent response (OR = 8.76, 95% CI = 2.28-33.61, p = 0.002), and abnormal cVEMP (OR = 7.47, 95% CI = 4.65-12.01, p < 0.00001) were higher in BPPV patients. But there was no significant difference in the n23 mean latency (MD = 0.37, 95% CI = -0.23-0.98, p = 0.22) and the AR of cVEMP (MD = 3.95, 95% CI = -4.75-12.65, p = 0.37) between BPPV patients and healthy controls. In the sub-group analysis based on age, only the result of the proportion of absent response of cVEMP indicated a significant difference existed (p = 0.002) between the studies with age-matched controls (OR = 2.78, 95% CI = 1.09-7.10, p = 0.03) and the studies without age-matched controls (OR = 53.85, 95% CI = 10.09-287.13, p < 0.00001). In the sub-group analysis of the proportion of abnormal cVEMP according to the diagnostic criteria of abnormal cVEMP, the result indicated no significant difference existed between the four groups (p = 0.61, I ² = 0%). In the sensitivity analysis, we obtained the consistent results after removing each study sequentially. Conclusion: The meta-analysis reveals that saccular dysfunction may be associated with BPPV occurrence, and neural degeneration in the saccular macula may be a potential pathogenesis for BPPV.

Failure on the Foam Eyes Closed Test of Standing Balance Associated With Reduced Semicircular Canal Function in Healthy Older Adults

OBJECTIVES

Standing on foam with eyes closed (FOEC) has been characterized as a measure of vestibular function; however, the relative contribution of vestibular function and proprioceptive function to the FOEC test has not been well described. In this study, the authors investigate the relationship between peripheral sensory systems (vestibular and proprioception) and performance on the FOEC test in a cohort of healthy adults.

DESIGN

A total of 563 community-dwelling healthy adults (mean age, 72.7 [SD, 12.6] years; range, 27 to 93 years) participating in the Baltimore Longitudinal Study of Aging were tested. Proprioceptive threshold (PROP) was evaluated with passive motion detection at the right ankle. Vestibulo-ocular reflex (VOR) gain was measured using video head impulses. Otolith function was measured with cervical and ocular vestibular-evoked myogenic potentials. Participants stood on FOEC for 40 sec while wearing BalanSens (BioSensics, LLC, Watertown, MA) to quantify center of mass sway area. A mixed-model multiple logistic regression was used to examine the odds of passing the FOEC test based on PROP, VOR, cervical vestibular-evoked myogenic potential, and ocular vestibular-evoked myogenic potential function in a multisensory model while controlling for age and gender.

RESULTS

The odds of passing the FOEC test decreased by 15% (p < 0.001) for each year of increasing age and by 8% with every 0.1 reduction in VOR gain (p = 0.025). Neither PROP nor otolith function was significantly associated with passing the FOEC test.

CONCLUSIONS

Failure to maintain balance during FOEC may serve as a proxy for rotational vestibular contributions to postural control. Semicircular canals are more sensitive to low-frequency motion than otoliths that may explain these relationships because standing sway is dominated by lower frequencies. Lower VOR gain and increased age independently decreased the odds of passing the test.

Children with posterior semicircular canal dehiscence: A case series

Posterior semicircular canal dehiscence is a rare condition and can cause a variety of symptoms. We report three cases of children between 5 and 12 years of age with a PSCD. They all presented with different complaints as follows: Tullio phenomenon in the first case, conductive hearing loss in the second and, conductive hearing loss and pulsatile tinnitus in the third. Imaging showed in all cases a PSCD on the right side, caused by a prominent jugular bulb (high riding bulb). We describe the clinical, audiometric and radiological findings, and discuss the management and therapy. A conservative "wait and see" approach is recommended, especially with children, because of the possible complications of surgery and the possibility that the symptoms will lessen with the skull base osseous maturation.

Air-Conducted Vestibular Evoked Myogenic Potential Testing in Children, Adolescents, and Young Adults: Thresholds, Frequency Tuning, and Effects of Sound Exposure

OBJECTIVES

Pediatric vestibular evaluations incorporate cervical and ocular vestibular evoked myogenic potential (c- and oVEMP, respectively) testing; however, in children, c- and oVEMP thresholds have been minimally investigated and frequency tuning is unknown. Children are also at risk for unsafe sound exposure secondary to VEMP. While it is unknown if VEMP threshold testing leads to cochlear changes, it is possible that this risk increases due to the increased number of trials needed to obtain a threshold. Obtaining VEMP thresholds at various frequencies in children provides further information for pediatric normative VEMP data. Assessing for cochlear changes after VEMP threshold testing would provide information on the safety of threshold VEMP testing in children. The objectives of this study were to (1) characterize c- and oVEMP thresholds in children, adolescents, and young adults with normal hearing using 500 and 750 Hz tone burst (TB) stimuli, (2) compare frequency tuning of 500 and 750 Hz TB, and (3) assess whether cochlear changes exist after VEMP threshold testing. It is hypothesized that children, adolescents, and young adults would not show age-related changes to the vestibular system. Therefore, reliable VEMP thresholds would be seen below maximum acoustical stimulation levels (e.g., <125 dB SPL) and frequency tuning will be similar for 500 and 750 Hz TB stimuli.

DESIGN

Ten children (age 4-9), 10 adolescents (age 10-19), and 10 young adults (age 20-29) with normal hearing and tympanometry participated. All subjects received c- and oVEMP testing at maximum stimulation and threshold. To address frequency tuning, but not exceed recommended sound exposure allowance, subjects received a 500 Hz TB stimulus in one ear and a 750 Hz TB stimulus in the other ear. Subjects completed tympanometry pre-VEMP, and audiometric threshold testing, distortion product otoacoustic emission testing, and subjective questionnaire pre- and post-VEMP to study the effect of VEMP exposure on cochlear function for each stimulus frequency.

RESULTS

(1) cVEMP thresholds were determined for both stimulus frequencies for children (500 Hz = 106 dB SPL; 750 Hz = 106 dB SPL), adolescents (500 Hz = 107.5 dB SPL; 750 Hz = 109.5 dB SPL), and young adults (500 Hz = 111.5 dB SPL; 750 Hz = 112 dB SPL). oVEMP thresholds were also obtained in response to both stimulus frequencies for children (500 Hz = 111.1 dB SPL; 750 Hz = 112.2 dB SPL), adolescents (500 Hz = 112.5 dB SPL; 750 Hz = 114.5 dB SPL), and young adults (500 Hz = 116 dB SPL; 750 Hz = 117 dB SPL). Similar thresholds were found between groups except for children who had significantly lower thresholds compared with adults for cVEMP (500 Hz: p = 0.002; 750 Hz: p = 0.004) and oVEMP (500 Hz: p = 0.01; 750 Hz: p = 0.02). In addition, equivalent ear-canal volume and VEMP thresholds were linearly correlated. (2) There was no significant effect of stimulus frequency on VEMP response rates, latencies, peak to peak amplitudes, or thresholds, suggesting similar frequency tuning for 500 and 750 Hz. (3) There were no significant effects of VEMP threshold testing on cochlear function for either stimulus frequency.

CONCLUSIONS

Children, adolescents, and young adults show VEMP thresholds below high stimulation levels and had similar frequency tuning between 500 and 750 Hz. Use of 750 Hz could be regarded as the safer stimuli due to its shorter duration and thus reduced sound exposure. Children with smaller ear-canal volume had present responses at maximum stimulation and lower thresholds, suggesting that VEMP testing could be initiated at lower acoustic levels to minimize sound exposure and optimize testing.

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.

Effects of High Sound Exposure During Air-Conducted Vestibular Evoked Myogenic Potential Testing in Children and Young Adults

OBJECTIVES

Vestibular evoked myogenic potential (VEMP) testing is increasingly utilized in pediatric vestibular evaluations due to its diagnostic capability to identify otolith dysfunction and feasibility of testing. However, there is evidence demonstrating that the high-intensity stimulation level required to elicit a reliable VEMP response causes acoustic trauma in adults. Despite utility of VEMP testing in children, similar findings are unknown. It is hypothesized that increased sound exposure may exist in children because differences in ear-canal volume (ECV) compared with adults, and the effect of stimulus parameters (e.g., signal duration and intensity) will alter exposure levels delivered to a child's ear. The objectives of this study are to (1) measure peak to peak equivalent sound pressure levels (peSPL) in children with normal hearing (CNH) and young adults with normal hearing (ANH) using high-intensity VEMP stimuli, (2) determine the effect of ECV on peSPL and calculate a safe exposure level for VEMP, and (3) assess whether cochlear changes exist after VEMP exposure.

DESIGN

This was a 2-phase approach. Fifteen CNH and 12 ANH participated in phase I. Equivalent ECV was measured. In 1 ear, peSPL was recorded for 5 seconds at 105 to 125 dB SPL, in 5-dB increments for 500- and 750-Hz tone bursts. Recorded peSPL values (accounting for stimulus duration) were then used to calculate safe sound energy exposure values for VEMP testing using the 132-dB recommended energy allowance from the 2003 European Union Guidelines. Fifteen CNH and 10 ANH received cervical and ocular VEMP testing in 1 ear in phase II. Subjects completed tympanometry, pre- and postaudiometric threshold testing, distortion product otoacoustic emissions, and questionnaire addressing subjective otologic symptoms to study the effect of VEMP exposure on cochlear function.

RESULTS

(1) In response to high-intensity stimulation levels (e.g., 125 dB SPL), CNH had significantly higher peSPL measurements and smaller ECVs compared with ANH. (2) A significant linear relationship between equivalent ECV (as measured by diagnostic tympanometry) and peSPL exists and has an effect on total sound energy exposure level; based on data from phase I, 120 dB SPL was determined to be an acoustically safe stimulation level for testing in children. (3) Using calculated safe stimulation level for VEMP testing, there were no significant effect of VEMP exposure on cochlear function (as measured by audiometric thresholds, distortion product otoacoustic emission amplitude levels, or subjective symptoms) in CNH and ANH.

CONCLUSIONS

peSPL sound recordings in children's ears are significantly higher (~3 dB) than that in adults in response to high-intensity VEMP stimuli that are commonly practiced. Equivalent ECV contributes to peSPL delivered to the ear during VEMP testing and should be considered to determine safe acoustic VEMP stimulus parameters; children with smaller ECVs are at risk for unsafe sound exposure during routine VEMP testing, and stimuli should not exceed 120 dB SPL. Using 120 dB SPL stimulus level for children during VEMP testing yields no change to cochlear function and reliable VEMP responses.

Otolith dysfunction in recurrent benign paroxysmal positional vertigo after mild traumatic brain injury

BACKGROUND

The pathogenesis of recurrence of traumatic benign paroxysmal positional vertigo (BPPV) is poorly understood by far.

OBJECTIVES

To evaluate the value of secondary otolith dysfunction using vestibular evoked myogenic potential (VEMP) test in the pathogenesis of recurrence of BPPV after mild traumatic brain injury (mTBI).

MATERIAL AND METHODS

We reviewed 42 patients with BPPV after mTBI. According to recurrence, patients were divided into two groups. Both cervical VEMP (cVEMP) and ocular VEMP (oVEMP) tests were performed on all of them.

RESULTS

We detected abnormal cVEMP responses in four (26.7%) patients in the recurrent BPPV group after mTBI and five (18.5%) patients in the non-recurrent BPPV group after mTBI, and there was no significant difference between both groups. We detected abnormal oVMEP responses in nine (60.0%) patients in the recurrent BPPV group after mTBI and six (22.2%) patients in the non-recurrent BPPV group after mTBI, and there was a significant difference between both groups.

CONCLUSIONS AND SIGNIFICANCE

Our study shows that oVEMP abnormalities in recurrent BPPV group after mTBI are significantly higher than those in non-recurrent BPPV group after mTBI. Therefore, we can conclude that secondary utricular dysfunction may be a potential pathogenesis of recurrence of traumatic BPPV.

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.

Animal Models of Vestibular Evoked Myogenic Potentials: The Past, Present, and Future

Vestibular-evoked myogenic potentials (VEMPs) provide a simple and cost-effective means to assess the patency of vestibular reflexes. VEMP testing constitutes a core screening method in a clinical battery that probes vestibular function. The confidence one has in interpreting the results arising from VEMP testing is linked to a fundamental understanding of the underlying functional anatomy and physiology. In this review, we will summarize the key role that studies across a range of animal models have fulfilled in contributing to this understanding, covering key findings regarding the mechanisms of excitation in the sensory periphery, the processing of sensory information in central networks, and the distribution of reflexive output to the motor periphery. Although VEMPs are often touted for their simplicity, work in animals models have emphasized how vestibular reflexes operate within a broader behavioral and functional context, and as such vestibular reflexes are influenced by multisensory integration, governed by task demands, and follow principles of muscle recruitment. We will conclude with considerations of future questions, and the ways in which studies in current and emerging animal models can contribute to further use and refinement of this test for both basic and clinical research purposes.

Bilateral Vestibular Weakness

Bilateral vestibular weakness (BVW) is a rare cause of imbalance. Patients with BVW complain of oscillopsia. In approximately half of the patients with BVW, the cause remains undetermined; in the remainder, the most common etiology by far is gentamicin ototoxicity, followed by much rarer entities such as autoimmune inner ear disease, meningitis, bilateral Ménière’s disease, bilateral vestibular neuritis, and bilateral vestibular schwannomas. While a number of bedside tests may raise the suspicion of BVW, the diagnosis should be confirmed by rotatory chair testing. Treatment of BVW is largely supportive. Medications with the unintended effect of vestibular suppression should be avoided.

Effects of motion sickness severity on the vestibular-evoked myogenic potentials

BACKGROUND

Motion sickness is a common debilitating condition associated with both actual and perceived motion. Despite the commonality, little is known about the underlying physiological mechanisms. One theory proposes that motion sickness arises from a mismatch between reality and past experience in vertical motions. Physiological tests of the vestibular system, however, have been inconclusive regarding the underlying pathogenesis. Cervical vestibular-evoked myogenic potentials (cVEMPs) arise from the saccule, which responds to vertical motion. If vertical motion elicits motion sickness, the cVEMP should be affected.

PURPOSE

The purpose of this investigation was to determine if cVEMP characteristics differ among individuals with a range of motion sickness susceptibility from negligible to severe. The hypothesis was that individuals with high susceptibility would have larger cVEMP amplitudes and shorter cVEMP latencies relative to those who are resistant to motion sickness.

RESEARCH DESIGN

The study had two parts. The first was quasi-experimental in which participants comprised three groups based on susceptibility to motion sickness (low, mild-moderate, high) as identified on the short version of the Motion Sickness Susceptibility Questionnaire (MSSQ-S). The second part of the study was correlational and evaluated the specific relationships between the degree of motion sickness susceptibility and characteristics of the VEMPs.

STUDY SAMPLE

A total of 24 healthy young adults (ages 20-24 yr) were recruited from the university and the community without regard to motion sickness severity.

DATA COLLECTION AND ANALYSIS

Participants took the MSSQ-S, which quantifies susceptibility to motion sickness. The participants had a range of motion sickness susceptibility with MSSQ raw scores from 0.0-36.6, which correspond to percent susceptibility from 0.0-99.3%. VEMPs were elicited by 500 Hz tone-bursts monaurally in both ears at 120 dB pSPL. MSSQ-S percent scores were used to divide the participants into low, mild-moderate, and high susceptibility groups. A fixed general linear model with repeated-measures analysis of variance tested cVEMP characteristics for the susceptibility groups (between participants) and ears (within participants). A univariate analysis of variance tested the cVEMP interaural amplitudes across groups. The second analysis was a regression of the severity of motion sickness in percent on cVEMP characteristics. Significance was defined as p < 0.05.

RESULTS

Participants in the high susceptibility group had significantly higher cVEMP amplitudes than those in the low susceptibility group. cVEMP amplitudes did not differ between ears, and latencies did not differ between the two groups or between ears. Regression analysis on MSSQ-S percent susceptibility by VEMP amplitudes revealed a best-fit cubic function in both ears, with r(2) values of more than 42%. The interaural asymmetry ratio was negatively associated with motion sickness susceptibility (r(2) = 0.389).

CONCLUSIONS

The current study is the first to report that greater susceptibility to motion sickness is associated with larger cVEMP amplitudes and lower interaural cVEMP asymmetries. Larger interaural asymmetries in cVEMPs did not promote motion sickness susceptibility. The cVEMP findings implicate the saccule and its neural pathways in the production of motion sickness and are consistent with the theory that vertical motions elicit motion sickness. Motion sickness susceptibility may contribute to the variability in normative cVEMP amplitudes.

Effect of Electrode Montage and Head Position on Air-Conducted Ocular Vestibular Evoked Myogenic Potential

PURPOSE

The purpose of this investigation was to identify the optimal recording parameters for evoking the ocular vestibular evoked myogenic potential (oVEMP) using air-conduction stimuli.

METHOD

Subjects were 17 otologically and neurologically intact adults (age: M = 24.18 years, SD = 1.91 years). The oVEMP responses were elicited using a 500-Hz tone burst air-conduction stimulus presented at an intensity of 95 dB nHL. The setting was a balance function laboratory that was part of a large tertiary care otology clinic.

RESULTS

The oVEMP electrode montage and body position that yielded the largest oVEMP amplitude was the belly-tendon montage (Sandhu, George, & Rea, 2013), recorded with the subject in the sitting position. The N1 latency recorded with the belly-tendon montage was significantly shorter than that recorded for the infraorbital montage in both the sitting and supine positions.

CONCLUSION

The belly-tendon recording montage with the subject sitting yields significantly larger oVEMP amplitudes and shorter N1 latencies than do traditional bipolar infraorbital recordings.

Altered Cervical Vestibular-Evoked Myogenic Potential in Children with Attention Deficit and Hyperactivity Disorder

OBJECTIVE

Emerging evidence suggests that children with attention deficit and hyperactivity disorder (ADHD) present more difficulties in standing and walking balance than typically developing children. Most of previous studies have assessed these functions using postural and sensory organization tests showing differences in balance performance between control and ADHD children. However, to date, it is unknown whether these balance alterations are accompanied with vestibular dysfunction. The principal aim of this study is to evaluate vestibular otolith function in ADHD and matched control children.

METHODS

We assessed vestibular otolith function in children with ADHD and controls using the subjective visual vertical (SVV) bucket test and cervical vestibular-evoked myogenic potentials (cVEMPs). In addition, gait and balance were evaluated using the dynamic gait index (DGI) and computerized posturography.

RESULTS

Non-significant differences between groups were obtained in SVV evaluation. DGI results show lower scores for overall test performance in children with ADHD (p < 0.001), while computerized postural recordings showed significant differences for the limit of stability between groups (p = 0.02). cVEMPs in response to 500 Hz tone bursts presented at 100 dB were absent or reduced in children with ADHD, as revealed by differences in P1 and N1 peak-to-peak amplitudes between groups (p < 0.01).

CONCLUSION

These findings suggest that vestibular brainstem reflexes are altered in a subset of children with ADHD. We propose to include cVEMP reflexes in the clinical evaluation of ADHD patients.

Aging and wave-component latency delays in oVEMP and cVEMP: a systematic review with meta-analysis

INTRODUCTION

The natural aging process may result in morphological changes in the vestibular system and in the afferent neural pathway, including loss of hair cells, decreased numbers of vestibular nerve cells, and loss of neurons in the vestibular nucleus. Thus, with advancing age, there should be a decrease in amplitudes and an increase in latencies of the vestibular evoked myogenic potentials, especially the prolongation of p13 latency. Moreover, many investigations have found no significant differences in latencies with advancing age.

OBJECTIVE

To determine if there are significant differences in the latencies of cervical and ocular evoked myogenic potentials between elderly and adult patients.

METHODS

This is a systematic review with meta-analysis of observational studies, comparing the differences of these parameters between elderly and young adults, without language or date restrictions, in the following databases: Pubmed, ScienceDirect, SCOPUS, Web of Science, SciELO and LILACS, in addition to the gray literature databases: OpenGrey.eu and DissOnline, as well as Research Gate.

RESULTS

The n1 oVEMP latencies had a mean delay in the elderly of 2.32ms with 95% CI of 0.55-4.10ms. The overall effect test showed p=0.01, disclosing that such difference was significant. The heterogeneity found was I²=96% (p<0.001). Evaluation of p1 latency was not possible due to the low number of articles selected for this condition. cVEMP analysis was performed in 13 articles. For the p13 component, the mean latency delay in the elderly was 1.34ms with 95% CI of 0.56-2.11ms. The overall effect test showed a p<0.001, with heterogeneity value I²=92% (p<0.001). For the n23 component, the mean latency delay for the elderly was 2.82ms with 95% CI of 0.33-5.30ms. The overall effect test showed p=0.03. The heterogeneity found was I²=99% (p<0.001).

CONCLUSION

The latency of oVEMP n1 wave component and latencies of cVEMP p13 and n23 wave components are longer in the elderly aged >60 years than in young adults.

Further studies of the effects of aging on arginine metabolites in the rat vestibular nucleus and cerebellum

Some studies have demonstrated that aging is associated with impaired vestibular reflexes, especially otolithic reflexes, resulting in postural instability. However, the neurochemical basis of these age-related changes is still poorly understood. The l-arginine metabolic system has been implicated in changes in the brain associated with aging. In the current study, we examined the levels of l-arginine and its metabolizing enzymes and downstream metabolites in the vestibular nucleus complex (VNC) and cerebellum (CE) of rats with and without behavioral testing which were young (4months old), middle-aged (12months old) or aged (24months old). We found that aging was associated with lower nitric oxide synthase activity in the CE of animals with testing and increased arginase in the VNC and CE of animals with testing. l-citrulline and l-ornithine were lower in the VNC of aged animals irrespective of testing, while l-arginine and l-citrulline were lower in the CE with and without testing, respectively. In the VNC and CE, aging was associated with lower levels of glutamate in the VNC, irrespective of testing. In the VNC it was associated with higher levels of agmatine and putrescine, irrespective of testing. In the CE, aging was associated with higher levels of putrescine in animals without testing and with higher levels of spermine in animals with testing, and spermidine, irrespective of testing. Multivariate analyses indicated significant predictive relationships between the different variables, and there were correlations between some of the neurochemical variables and behavioral measurements. Cluster analyses revealed that aging altered the relationships between l-arginine and its metabolites. The results of this study demonstrate that there are major changes occurring in l-arginine metabolism in the VNC and CE as a result of age, as well as behavioral activity.