Band limited chirp stimulation in vestibular evoked myogenic potentials

The Narrowband CE-Chirp Stimulus Does Not Necessarily Produce More Robust Cervical Vestibular Evoked Myogenic Potential

OBJECTIVE

Various studies have been conducted to search for the most optimal stimulus for eliciting cervical vestibular evoked myogenic potential (cVEMP). More recently, there is a growing interest to study the usefulness of chirp stimuli in cVEMP recording. Nevertheless, contradictory outcomes have been reported across the studies, and further research with larger samples would be beneficial to provide better insight into this matter. As such, the present study was carried out to compare cVEMP results between narrowband (NB) CE-Chirp (centered at 500 Hz) and 500 Hz tone burst stimuli.

DESIGN

In this study that employed a comparative study design, 98 normally hearing adults aged between 19 and 24 years were enrolled. All of them underwent the cVEMP testing based on the recommended test protocol. The stimuli were a 500 Hz tone burst and a NB CE-Chirp (360-720 Hz) presented through insert earphones at an intensity level of 120.5 dB peSPL.

RESULTS

For each stimulus, cVEMP results did not differ significantly between the ears ( p > 0.05). Relative to the 500 Hz tone burst, the NB CE-Chirp stimulus produced statistically shorter P1 and N1 latencies ( p < 0.001). On the other hand, P1-N1 amplitude was found to be comparable between the two stimuli ( p > 0.05).

CONCLUSIONS

The present study did not find any supporting evidence that the NB CE-Chirp stimulus (centered at 500 Hz) outperformed the conventional 500 Hz tone burst in the cVEMP testing. Both stimuli are considered equally appropriate to record cVEMP responses in clinical settings.

Chirp-Evoked VEMPs: A Test-Retest Reliability Study

OBJECTIVES

To determine the test-retest reliability of cervical and ocular vestibular-evoked myogenic potentials (c&oVEMP) evoked by 500 Hz narrowband (NB) CE-Chirp and broadband (BB) CE-Chirp stimuli.

DESIGN

Twenty healthy participants (10 female) were tested twice on the same day to determine the within-session reliability and 1 week later to determine the between-session reliability. The latency, amplitude, and asymmetry ratio of c&oVEMPs elicited by 95 dB nHL air-conducted (AC) 500 Hz NB CE-Chirp and BB CE-Chirp were recorded bilaterally.

RESULTS

A moderate to good between-session reliability with intraclass correlation coefficient (ICC) values ranging from 0.52 to 0.82 was observed for cVEMP latency, amplitude, and asymmetry ratio evoked by 500 Hz NB CE-Chirp, as well as for the BB CE-Chirp cVEMP amplitude (ICC of 0.70 and 0.84). In contrast, an overall poor reliability ICC values between 0.30 and 0.42 for cVEMP latency and asymmetry ratio were observed for BB CE-Chirp. For the oVEMP, overall poor between-session reliability for all response parameters evoked by the 500 Hz NB CE-Chirp and the BB CE-Chirp was observed.

CONCLUSIONS

The 500 Hz NB CE-Chirp was more reliable than the BB CE-Chirp in terms of cVEMP latency, amplitude, and asymmetry ratio. Further investigation using the standard electrode montage is necessary to assess the test-retest reliability of the chirp-evoked oVEMP.

Cervical vestibular evoked myogenic potential (cVEMP) findings in adults with sensorineural hearing loss (SNHL): comparisons between 500 Hz tone burst and narrowband CE-Chirp stimuli

There has been a growing interest in studying the usefulness of chirp stimuli in recording cervical vestibular evoked myogenic potential (cVEMP) waveforms. Nevertheless, the study outcomes are debatable and require verification. In view of this, the aim of the present study was to compare cVEMP results when elicited by 500 Hz tone burst and narrowband (NB) CE-Chirp stimuli in adults with sensorineural hearing loss (SNHL). Fifty adults with bilateral SNHL (aged 20-65 years) underwent the cVEMP testing based on the established protocol. The 500 Hz tone burst and NB CE-Chirp (centred at 500 Hz) stimuli were presented to each ear at an intensity level of 120.5 dB peSPL. P1 latency, N1 latency, and P1-N1 amplitude values were analysed accordingly. The NB CE-Chirp stimulus produced significantly shorter P1 and N1 latencies (p < 0.001) with large effect sizes (d > 0.80). In contrast, both stimuli elicited cVEMP responses with P1-N1 amplitude values that were not statistically different from one another (p = 0.157, d = 0.15). Additionally, age and hearing level were found to be significantly correlated (r = 0.56, p < 0.001), as were age and cVEMP amplitude for each stimulus (p < 0.001). To conclude, since both stimuli were presented at an equivalent intensity level (in dB peSPL), the shorter P1 and N1 latencies of cVEMP produced by the NB CE-Chirp stimulus (centred at 500 Hz) were unlikely due to enhanced saccular stimulation. Another more sensible reason is the temporal adjustment of the chirp stimulus.

Vestibular Testing-New Physiological Results for the Optimization of Clinical VEMP Stimuli

Both auditory and vestibular primary afferent neurons can be activated by sound and vibration. This review relates the differences between them to the different receptor/synaptic mechanisms of the two systems, as shown by indicators of peripheral function-cochlear and vestibular compound action potentials (cCAPs and vCAPs)-to click stimulation as recorded in animal studies. Sound- and vibration-sensitive type 1 receptors at the striola of the utricular macula are enveloped by the unique calyx afferent ending, which has three modes of synaptic transmission. Glutamate is the transmitter for both cochlear and vestibular primary afferents; however, blocking glutamate transmission has very little effect on vCAPs but greatly reduces cCAPs. We suggest that the ultrafast non-quantal synaptic mechanism called resistive coupling is the cause of the short latency vestibular afferent responses and related results-failure of transmitter blockade, masking, and temporal precision. This "ultrafast" non-quantal transmission is effectively electrical coupling that is dependent on the membrane potentials of the calyx and the type 1 receptor. The major clinical implication is that decreasing stimulus rise time increases vCAP response, corresponding to the increased VEMP response in human subjects. Short rise times are optimal in human clinical VEMP testing, whereas long rise times are mandatory for audiometric threshold testing.

Using macular velocity measurements to relate parameters of bone conduction to vestibular compound action potential responses

To examine mechanisms responsible for vestibular afferent sensitivity to transient bone conducted vibration, we performed simultaneous measurements of stimulus-evoked vestibular compound action potentials (vCAPs), utricular macula velocity, and vestibular microphonics (VMs) in anaesthetized guinea pigs. Results provide new insights into the kinematic variables of transient motion responsible for triggering mammalian vCAPs, revealing synchronized vestibular afferent responses are not universally sensitive to linear jerk as previously thought. For short duration stimuli (< 1 ms), the vCAP increases magnitude in close proportion to macular velocity and temporal bone (linear) acceleration, rather than other kinematic elements. For longer duration stimuli, the vCAP magnitude switches from temporal bone acceleration sensitive to linear jerk sensitive while maintaining macular velocity sensitivity. Frequency tuning curves evoked by tone-burst stimuli show vCAPs increase in proportion to onset macular velocity, while VMs increase in proportion to macular displacement across the entire frequency bandwidth tested between 0.1 and 2 kHz. The subset of vestibular afferent neurons responsible for synchronized firing and vCAPs have been shown previously to make calyceal synaptic contacts with type I hair cells in the striolar region of the epithelium and have irregularly spaced inter-spike intervals at rest. Present results provide new insight into mechanical and neural mechanisms underlying synchronized action potentials in these sensitive afferents, with clinical relevance for understanding the activation and tuning of neurons responsible for driving rapid compensatory reflex responses.

Comparison of Chirp Versus Tone Burst- and Click-Evoked Masseteric Vestibular Evoked Myogenic Potentials in Normal-Hearing Adults

PURPOSE

This study aimed at comparing narrowband Claus Elberling level-specific chirp (NB CE-Chirp)-, click-, and tone burst-evoked masseteric vestibular evoked myogenic potentials (mVEMPs).

METHOD

Within-group study design and purposive sampling were performed. A total of 25 normal-hearing individuals participated in the study. The zygomatic electrode montage was used to elicit ipsilateral mVEMP responses using a 500-Hz NB CE-Chirp, a click of 100-μs duration, and a 500-Hz tone burst stimulus. Each of the responses was analyzed based on the absolute peak latency of P11 and N21, the electromyography-scaled peak-to-peak amplitude of the P11-N21 complex, and the interaural asymmetry ratio.

RESULTS

A total of 50 ears were tested and had 100% mVEMP responses. The latencies of click-evoked and 500-Hz NB CE-Chirp-evoked mVEMPs were significantly shorter than those of 500-Hz tone burst-evoked mVEMPs (p < .05) for both ears. It revealed a significantly superior P11-N21 amplitude of the 500-Hz NB CE-Chirp and tone burst than clicks for both ears. Intraclass correlation coefficient revealed moderate to excellent test-retest reliability for mVEMP parameters across three different stimulations.

CONCLUSION

The present study supports 500 Hz NB CE-Chirps as effective and reliable stimuli as tone bursts in eliciting mVEMP responses.

Multifrequency Narrowband Chirp Evoked Cervical Vestibular Myogenic Potentials: Evaluation of Responses in Normal-Hearing Young Adults

Purpose:

The study aimed to explore the various parameters of multifrequency narrowband Claus Elberling chirp (NB CE-chirp) evoked cervical vestibular evoked myogenic potentials (cVEMPs) in normal-hearing healthy young adults. The study also attempted to define the optimal frequency tuning characteristic of NB CE-chirp evoked cVEMPs.

Method:

cVEMP was performed on 26 young healthy adults using four different NB CE-chirps centered at 500, 1000, 2000, and 4000 Hz. The neck torsion method was applied for electrode placement. To have the acute recording, visual feedback of sternocleidomastoid muscle contraction was provided, and electromyography (EMG) scaling was done.

Results:

cVEMPs were present for 100% across all frequencies except at 4000 Hz. Amplitudes between each pair of frequencies were significantly different for EMG scaled and unscaled conditions. Frequency tuning was observed at 500 Hz regardless of scaling done. Positive peak 1 of cVEMP (P1) latencies showed no differences between frequencies while both negative peak 1 of cVEMP and the complex of positive peak 1 and negative peak 1 of cVEMP (P1N1) interpeak latency values decreased with increasing frequency. Interaural amplitude asymmetry ratio showed no difference between scaled and unscaled amplitudes. Intraclass correlation revealed a range of test–retest reliability across frequencies. EMG unscaled amplitude were having relatively lower test–retest reliability consistently across frequencies

Conclusions:

Differences in amplitudes between frequencies with a maximum at 500 Hz can be attributed to the low frequency centered saccular response. No differences in P1 were observed. Yet, N1 latency and P1N1 interpeak latency difference gradually shortened with the decrement in the stimulus duration as the stimulation frequency increased. The lower reliability of EMG unscaled amplitude across frequencies supports the need to use EMG scaling to avoid confounding variables related to muscle contraction.

Comparison of cervical and ocular vestibular-evoked myogenic potential responses between tone burst versus chirp stimulation

PURPOSE

To compare the effectiveness of chirp and tone burst stimuli in oVEMP and cVEMP testing for healthy adults METHODS: This study was conducted in 56 healthy volunteers (112 ears). Ocular and cervical VEMP (oVEMP, cVEMP) tests were performed for each participant using tone burst and chirp stimuli. VEMP response rates, latency of each peak (p1-n1, n1-p1), peak to peak amplitude (p1-n1 amplitude and n1-p1 amplitude), and rectified amplitudes were measured and compared between these two different stimuli.

RESULTS

VEMP response rates with chirp stimuli are higher than the tone burst stimuli for both cVEMP and oVEMP tests (The difference was statistically significant for oVEMP, p = 0.001). Chirp stimuli have higher p1n1 amplitude and rectified amplitude and shorter p1and n1 latency then tone burst stimuli for cVEMP (p = 0.015, p = 0.007, p < 0.001, p < 0.001, respectively). Chirp stimuli also have higher n1p1 amplitude and shorter n1and p1 latency then tone burst stimuli for oVEMP (p = 0.006, p < 0.001, p < 0.001, respectively).

CONCLUSION

The present findings show that the chirp stimulus triggers earlier VEMP responses with higher amplitudes than the tone burst stimulus during cVEMP and oVEMP testing. VEMP response rate with chirp stimulus is also higher than the tone burst. Therefore chirp stimulus can be used in VEMP testing as effectively as, if not more than, tone burst stimulus in clinical practice.

Cervical and ocular vestibular evoked myogenic potential: A comparison of narrowband chirp, broadband chirp, tone burst and click stimulation

OBJECTIVES

To compare the response rate and response parameters of cervical and ocular vestibular evoked myogenic potentials (c&oVEMP) elicited by narrowband (NB) and broadband (BB) CE-Chirp, with the more classical tone burst (TB) and click VEMPs.

DESIGN

The response rate, latency, amplitude and asymmetry ratio of c&oVEMPs elicited by 95 dB nHL air conducted (AC) 500 Hz NB CE-chirp, BB CE-chirp, 500 Hz TB and click stimuli were recorded bilaterally.

STUDY SAMPLE

20 male and 38 female participants (19-39 years).

RESULTS

For the cVEMP, the highest response rate was found for NB chirp (100%), followed by TB (91%), BB chirp (87%) and finally click (85%). A similar order was seen for oVEMP with percentages of 100%; 57%, 57%, and 43%. The 500 Hz NB CE-Chirp elicited significantly shorter cVEMP P1 and N1 latencies and significantly larger c&oVEMP amplitudes compared to all other stimuli. BB CE-Chirp elicited significantly shorter c&oVEMP P1 and N1 latencies with smaller amplitudes compared to TB. Asymmetry ratios were not statistically significant for all comparisons.

CONCLUSION

The 500 Hz NB CE-chirp provides the highest response rates, shorter latencies and larger amplitudes, and therefore seem a promising stimulus for reliably measuring c&oVEMPs in clinical practice.

Using Narrow Band CE-Chirps to Elicit Cervical Vestibular Evoked Myogenic Potentials

Objectives:

To compare the effects of Narrow band CE-Chirps (NB CE-Chirps) and tone bursts (TBs) at 500 Hz and 1000 Hz on the amplitudes and latencies in cervical vestibular evoked myogenic potentials (cVEMPs).

Design:

Thirty-one healthy adult volunteers of varying ages were tested by air conduction at 95 dB nHL. Recording conditions were randomized for each participant and each modality was tested twice.

Results:

NB CE-Chirps showed larger corrected amplitudes than TBs at 500 Hz (p < 0.001) which were themselves larger than NB CE-Chirps and TBs at 1000 Hz (p < 0.001). In older volunteers, NB CE-Chirps 500 and 1000 Hz had significantly higher response rates than TBs 500 Hz (p = 0.039). A negative correlation was observed between the corrected amplitudes and the age of the participants regardless of the stimulus and the frequency studied. The p13 and n23 latencies were not correlated with the age of the subjects.

Conclusions:

NB CE-Chirps at 500 Hz improved the corrected amplitudes of waveforms in cVEMPs as a result of a better frequency specificity compared with TBs. In the elderly, eliciting cVEMPs at a frequency of 1000 Hz might not be necessary to improve response rates with NB CE-Chirps. Additional studies including a higher number of healthy participants and patients with vestibular disorders are required to confirm these observations.

Optimizing Ocular Vestibular Evoked Myogenic Potentials With Narrow Band CE-Chirps

OBJECTIVES

To evaluate the effects of narrow band CE-Chirp (NB CE-Chirp) on the amplitudes and latencies in ocular vestibular evoked myogenic potentials (oVEMPs) at 500 and 1000 Hz in comparison with tone burst (TB).

DESIGN

Twenty-one healthy volunteers were included in the study and tested in air conduction with a "belly-tendon" montage. Recording conditions were randomized for each participant and each modality was tested twice to check the reproducibility of the procedure.

RESULTS

NB CE-Chirps at 500 Hz revealed larger n1-p1 amplitudes than 500 Hz TBs (p = .001), which were also larger than NB CE-Chirps and TBs at 1000 Hz (p = .022, p < .001, respectively). Besides, n1 and p1 latencies were shorter in NB CE-Chirp than in TB at 500 Hz (p < .001) and 1000 Hz (p < .001). The older the participants, the lower the amplitudes (p = .021, p = .031) and the longer the n1 (p = .030, p = .025) and p1 latencies (p < .001, p < .001) in 500 Hz NB CE-Chirps and 500 Hz TBs. Interaural asymmetry ratios were slightly higher in 500 Hz NB CE-Chirps as compared to 500 Hz TBs (p = .013).

CONCLUSIONS

NB CE-Chirps at 500 Hz improved the amplitudes of waveforms in oVEMPs. As for TBs with clicks before, enhancing oVEMPs amplitudes is an essential step to distinguish a healthy person from a patient with either utricular or its related pathways disorder and potentially minimize the risk of cochlear damages. Additional studies including a higher number of healthy participants and patients with vestibular disorders are required to confirm this hypothesis. The large interindividual variability of interaural asymmetry ratios in NB CE-Chirp and in TB at 500 Hz could be explained by the selected montage.

Can Narrow Band Chirp Stimulus Shake the Throne of 500 Hz Tone Burst Stimulus for Cervical Vestibular Myogenic Potentials?

Background and Objectives

The aim of the study was to compare effects of tone-burst (TB) and narrow-band (NB) Claus Elberling (CE)-chirp stimuli on amplitude, latency and interaural asymmetry ratio (IAR) of cervical vestibular evoked myogenic potentials (cVEMP) in healthy individuals.

Subjects and Methods

The study included 50 healthy volunteers. cVEMP procedure was carried out using 500 Hz TB and NB-CE-chirp stimulus (360-720 Hz, up-chirp) in random order. cVEMP were recorded at 100 dB nHL. For each ear and each stimulus, P1 latency, N1 latency and P1N1 amplitude were measured. IAR was also calculated.

Results

Mean age was 26.66±9.48 years. cVEMP’s in response to both TB and NB CE-chirp stimuli were obtained in all subjects. No statistically significant difference in P1 latency, N1 latency, and P1N1 amplitude was found between the right and left ears for both TB and NB CE-chirp stimuli (p>0.05). In both sides, P1 and N1 latencies were significantly shorter in NB CE-chirp stimulation compared to TB stimulation (p=0.000). In both sides, no statistically significant difference was found in P1N1 amplitude between two types of stimuli (p>0.05).

Conclusions

The chirp stimulus produces robust but earlier cVEMP than TB does. This largest series study on NB chirp cVEMP shows that NB chirp is a good and new reliable alternative.

Differences in bone conduction ocular vestibular evoked myogenic potentials to 500 Hz narrow band chirp stimulus and 500 Hz tone burst

OBJECTIVE

This study aims to investigate the differences of N1 latency, P1 latency and N1P1 amplitude in response to bone conducted 500 Hz tone burst and narrowband CE chirp stimulus in ocular vestibular evoked myogenic potentials (oVEMPs).

METHODS

Forty-two healthy volunteers were included in this prospective study. Subjects with abnormal otological examinations and otological diseases were excluded. oVEMPs were randomly recorded in response to BC 500 Hz narrowband (NB) chirp stimulus and BC 500 Hz tone burst. The stimulus intensity was 50 dB nHL for both 500 Hz tone burst and 500 Hz NB CE chirp stimulus. P1 latency, N1 latency, and N1P1 amplitude were measured, and these measurements were compared between these two types of stimuli.

RESULTS

Both types of stimuli elicited oVEMP in all subjects. N1 latency and P1 latency were significantly shorter (6.41 ms vs 10.84 ms; 10.64 ms vs 15.56 ms, respectively) for chirp stimulus (p < 0.05). N1P1 amplitude was significantly higher (11.64 vs 7.18 μV) for NB chirp stimulus (p < 0.05).

CONCLUSION

It is reasonable to conclude that the NB CE chirp stimulus is effective to elicit robust BC oVEMP in healthy subjects.

Normative Data of Ocular Vestibular Evoked Myogenic Potentials in Response to Chirp Stimulus

OBJECTIVES

This study aims at comparing the tone-burst (TB) and narrow-band (NB) CE-chirp stimuli in terms of amplitude, latency, and interaural asymmetry ratio (IAR) in ocular vestibular evoked myogenic potentials (oVEMP).

MATERIALS AND METHODS

In this prospective study, we enrolled 60 healthy subjects (27 men, 33 women) with a mean age of 25.83 (range, 18-48) years. Otological examination was normal in all the subjects. The subjects did not have any otological disease. All the subjects underwent oVEMP testing. We used 500 Hz TB stimulus and 500 Hz NB CE-chirp stimulus in random order. oVEMP test was performed at 100 dB normalized hearing level. P1 latency, N1 latency, and P1N1 amplitude were measured for each ear and stimulus, and IAR was calculated.

RESULTS

Ocular VEMPs were obtained from all the subjects for both the stimuli. P1 and N1 latencies were significantly shorter in chirp stimulus than in TB stimulus for both the sides (p<0.0001). P1 and N1 amplitudes were significantly higher for chirp stimulus than for TB stimulus for both the sides (p<0.0001). There was no significant difference between the ears in IAR between the 2 types of stimuli.

CONCLUSION

Narrow-band CE-chirp stimulus is an effective stimulus to evoke oVEMP with higher amplitudes and shortened latencies.

Cervical vestibular evoked myogenic potential with chirp sounds

BACKGROUND

There are only a few reports concerning cervical vestibular evoked myogenic potential (cVEMP) using chirp sound, and clinical indications/advantages of it are still unclear.

OBJECTIVE

To compare cVEMP using CE-chirp LS® with cVEMP using 500 Hz and 1000 Hz tone bursts (TB) and to investigate clinical indications/advantages of CE-chirp LS® for recording cVEMP.

METHODS

Sixteen patients with vestibular disorders (2men and 14 women) (18∼62, mean 42.9 years of age) were enrolled in this study. Participants underwent cVEMP testing using 500 Hz and 1000 Hz tone bursts (TB) and CE-chirp LS®. Response rate of P1-N1, corrected/normalized amplitude of P1-N1, latencies of P1 and N1, asymmetry ratio, and correlation of P1 latency to SLOPE in tuning property test (an index of endolymphatic hydrops) were compared.

RESULTS

Corrected/normalized amplitude of P1-N1 to CE-chirp LS® was smaller than corrected/normalized amplitude of P1-N1 to 500 Hz TB. Peak latencies to CE-chirp LS® were the shortest among the 3 types of stimulation. EH-positive ears according to the tuning property test had tendency of prolonged P1 latencies to CE-chirp LS®.

CONCLUSION

CE-chirp LS® is applicable for recording cVEMP with a similar diagnostic accuracy to TB. Prolongation of P1 latency in CE-chirp LS® might be an indicator of endolymphatic hydrops in the saccule.

Current diagnostic procedures for diagnosing vertigo and dizziness

Vertigo is a multisensory syndrome that otolaryngologists are confronted with every day. With regard to the complex functions of the sense of orientation, vertigo is considered today as a disorder of the sense of direction, a disturbed spatial perception of the body. Beside the frequent classical syndromes for which vertigo is the leading symptom (e.g. positional vertigo, vestibular neuritis, Menière’s disease), vertigo may occur as main or accompanying symptom of a multitude of ENT-related diseases involving the inner ear. It also concerns for example acute and chronic viral or bacterial infections of the ear with serous or bacterial labyrinthitis, disorders due to injury (e.g. barotrauma, fracture of the oto-base, contusion of the labyrinth), chronic-inflammatory bone processes as well as inner ear affections in the perioperative course. In the last years, diagnostics of vertigo have experienced a paradigm shift due to new diagnostic possibilities. In the diagnostics of emergency cases, peripheral and central disorders of vertigo (acute vestibular syndrome) may be differentiated with simple algorithms. The introduction of modern vestibular test procedures (video head impulse test, vestibular evoked myogenic potentials) in the clinical practice led to new diagnostic options that for the first time allow a complex objective assessment of all components of the vestibular organ with relatively low effort. Combined with established methods, a frequency-specific assessment of the function of vestibular reflexes is possible. New classifications allow a clinically better differentiation of vertigo syndromes. Modern radiological procedures such as for example intratympanic gadolinium application for Menière’s disease with visualization of an endolymphatic hydrops also influence current medical standards. Recent methodical developments significantly contributed to the possibilities that nowadays vertigo can be better and more quickly clarified in particular in otolaryngology.