Water irrigation versus air insufflation: A comparison of two caloric test protocols

Episodic Vestibular Symptoms in Children With a Congenital Cytomegalovirus Infection: A Case Series

OBJECTIVE

Congenital cytomegalovirus (cCMV) infection is the most common non-genetic cause of sensorineural hearing loss in children. Although cCMV-induced vestibular loss is demonstrated in several studies, the occurrence of vertigo has been described in only two cases to date. The aim of this paper is to discuss the underlying pathophysiology of recurrent vestibular symptoms in children with cCMV, based on five cases investigated in our center and an extensive research of the literature.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

PATIENTS

This case series describes five pediatric cCMV-patients (three boys, two girls). Four of them were symptomatic at birth, one was asymptomatic. Three patients underwent cochlear implantation. The age of onset of the vestibular symptoms varied from 2;0 to 7;3 years of age.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Details regarding the patient history and results of cranial imaging, audiological, vestibular, and neurological assessments were collected retrospectively.

RESULTS

The selected cases suffered from recurrent vestibular symptoms. All patients had delayed onset, fluctuating, and/or progressive hearing loss. In all cases, the attacks were accompanied with nausea and vomiting and occurred without clear-cut trigger. Migraine and epilepsy often were proposed as first diagnosis, although they could not be confirmed eventually. Four out of five patients were diagnosed with a peripheral vestibular deficit.

CONCLUSIONS

Diagnosis of vestibular symptoms in children with cCMV is complex, given the multiple morbidities than can occur. Peripheral vestibular causes should be considered in the diagnosis, as important vestibular deficits are demonstrated in this population.

Cognitive Function in Acquired Bilateral Vestibulopathy: A Cross-Sectional Study on Cognition, Hearing, and Vestibular Loss

BACKGROUND

Several studies have demonstrated cognitive deficits in patients with bilateral vestibulopathy (BVP). So far, little attention has been paid to the hearing status of vestibular patients when evaluating their cognition. Given the well-established link between sensorineural hearing loss (SNHL) and cognitive decline and the high prevalence of SNHL in BVP patients, it is therefore uncertain if the cognitive deficits in BVP patients are solely due to their vestibular loss or might be, partially, explained by a concomitant SNHL.

OBJECTIVE

To evaluate the link between cognition, hearing, and vestibular loss in BVP patients.

DESIGN

Prospective cross-sectional analysis of cognitive performance in patients with BVP and control participants without vestibular loss. Both groups included subjects with a variety of hearing (dys)function. Cognition was assessed by means of the Repeatable Battery for the Assessment of Neuropsychological Status for Hearing Impaired Individuals (RBANS-H).

RESULTS

Sixty-four BVP patients were evaluated and compared with 83 control participants. For each subscale and the totale RBANS-H scale a multiple linear regression model was fitted with the following variables: vestibular loss, hearing loss, age, gender, and education. Hearing loss seemed to be associated with worse outcome on the total RBANS-H scale and subscales immediate memory and language. Vestibular loss, on the other hand, was linked to worse performance on the attention subscale of the RBANS-H. Furthermore, we did not observe a correlation between saccular function and cognition.

CONCLUSION

This study has found general cognitive deficits in a large sample size of BVP patients. Multiple linear regression models revealed that both vestibular and hearing dysfunction were associated with different subscales of the cognitive test battery, the RBANS-H. Whereas hearing loss was associated with worse performance on total RBANS-H score, immediate memory and language, vestibular loss was observed to negatively affect attention performance.

Bilateral vestibulopathy: Diagnostic criteria Consensus document of the Classification Committee of the Bárány Society

This paper describes the diagnostic criteria for bilateral vestibulopathy (BVP) by the Classification Committee of the Bárány Society. The diagnosis of BVP is based on the patient history, bedside examination and laboratory evaluation. Bilateral vestibulopathy is a chronic vestibular syndrome which is characterized by unsteadiness when walking or standing, which worsen in darkness and/or on uneven ground, or during head motion. Additionally, patients may describe head or body movement-induced blurred vision or oscillopsia. There are typically no symptoms while sitting or lying down under static conditions.

The diagnosis of BVP requires bilaterally significantly impaired or absent function of the vestibulo-ocular reflex (VOR). This can be diagnosed for the high frequency range of the angular VOR by the head impulse test (HIT), the video-HIT (vHIT) and the scleral coil technique and for the low frequency range by caloric testing. The moderate range can be examined by the sinusoidal or step profile rotational chair test.

For the diagnosis of BVP, the horizontal angular VOR gain on both sides should be <0.6 (angular velocity 150–300°/s) and/or the sum of the maximal peak velocities of the slow phase caloric-induced nystagmus for stimulation with warm and cold water on each side <6°/s and/or the horizontal angular VOR gain <0.1 upon sinusoidal stimulation on a rotatory chair (0.1 Hz, Vmax = 50°/sec) and/or a phase lead >68 degrees (time constant of <5 seconds). For the diagnosis of probable BVP the above mentioned symptoms and a bilaterally pathological bedside HIT are required.

Complementary tests that may be used but are currently not included in the definition are: a) dynamic visual acuity (a decrease of ≥0.2 logMAR is considered pathological); b) Romberg (indicating a sensory deficit of the vestibular or somatosensory system and therefore not specific); and c) abnormal cervical and ocular vestibular-evoked myogenic potentials for otolith function.

At present the scientific basis for further subdivisions into subtypes of BVP is not sufficient to put forward reliable or clinically meaningful definitions. Depending on the affected anatomical structure and frequency range, different subtypes may be better identified in the future: impaired canal function in the low- or high-frequency VOR range only and/or impaired otolith function only; the latter is evidently very rare.

Bilateral vestibulopathy is a clinical syndrome and, if known, the etiology (e.g., due to ototoxicity, bilateral Menière’s disease, bilateral vestibular schwannoma) should be added to the diagnosis. Synonyms include bilateral vestibular failure, deficiency, areflexia, hypofunction and loss.

Sensitivity evaluation in air and water caloric stimulation of the vestibular organs using videonystagmography

INTRODUCTION

The aim of the study was to compare air and water caloric stimulation of the vestibular organs using videonystagmography (VNG).

MATERIAL AND METHODS

The study covered 18 women aged 21-63 and 11 men aged 21-74 years hospitalized at the ENT, without complaints for vertigo and/or balance disorders. The alternate binaural bithermal caloric test with cool 30°C and warm 44°C air or water irrigations (after 2h interval for the recordings) with the use of VNG was done.

RESULTS

All parameters of air and water vestibular caloric stimulations, assessed in the VNG, differed significantly but were within the normal range. The research showed a statistically significant difference between canal paresis but only for the left ear at 30°C and 44°C. Absolute directional preponderance, relative directional preponderance, vestibular excitability, slow component velocity, frequency were different statistically for both ears at both temperatures.

CONCLUSIONS

Our study showed that both air and water caloric stimulations were able to distinguish physiological and impaired vestibular function. The obtained results showed statistically higher response for water than air stimulation.

The human vestibular cortex revealed by coordinate-based activation likelihood estimation meta-analysis

The vestibular system contributes to the control of posture and eye movements and is also involved in various cognitive functions including spatial navigation and memory. These functions are subtended by projections to a vestibular cortex, whose exact location in the human brain is still a matter of debate (Lopez and Blanke, 2011). The vestibular cortex can be defined as the network of all cortical areas receiving inputs from the vestibular system, including areas where vestibular signals influence the processing of other sensory (e.g. somatosensory and visual) and motor signals. Previous neuroimaging studies used caloric vestibular stimulation (CVS), galvanic vestibular stimulation (GVS), and auditory stimulation (clicks and short-tone bursts) to activate the vestibular receptors and localize the vestibular cortex. However, these three methods differ regarding the receptors stimulated (otoliths, semicircular canals) and the concurrent activation of the tactile, thermal, nociceptive and auditory systems. To evaluate the convergence between these methods and provide a statistical analysis of the localization of the human vestibular cortex, we performed an activation likelihood estimation (ALE) meta-analysis of neuroimaging studies using CVS, GVS, and auditory stimuli. We analyzed a total of 352 activation foci reported in 16 studies carried out in a total of 192 healthy participants. The results reveal that the main regions activated by CVS, GVS, or auditory stimuli were located in the Sylvian fissure, insula, retroinsular cortex, fronto-parietal operculum, superior temporal gyrus, and cingulate cortex. Conjunction analysis indicated that regions showing convergence between two stimulation methods were located in the median (short gyrus III) and posterior (long gyrus IV) insula, parietal operculum and retroinsular cortex (Ri). The only area of convergence between all three methods of stimulation was located in Ri. The data indicate that Ri, parietal operculum and posterior insula are vestibular regions where afferents converge from otoliths and semicircular canals, and may thus be involved in the processing of signals informing about body rotations, translations and tilts. Results from the meta-analysis are in agreement with electrophysiological recordings in monkeys showing main vestibular projections in the transitional zone between Ri, the insular granular field (Ig), and SII.

Wet air as an alternative to traditional water irrigation during caloric vestibular testing

OBJECTIVES/HYPOTHESIS

To evaluate whether caloric vestibular testing by wet air (WAI) is better than by dry air (DAI) in comparison to the gold standard using water (WAT).

STUDY DESIGN

Prospective study, comparison with reference standard.

METHODS

Fifty volunteers with normal ear and balance function were enrolled in a prospective study. After side-specific warm and cold DAI, WAI, and WAT experimental nystagmuses were recorded using video-oculography. Peak slow nystagmus phase velocity (SPV) data at test culmination and the subjective tolerance of the methods were analyzed by visual analog scale.

RESULTS

The three methods differed significantly with respect to warm versus cold stimulation and stimulus side, with one exception. In the case of cold stimulation on the left side, SPV values did not differ between DAI and WAI. The intraclass correlation coefficients (ICCs) of WAT versus WAI were indicative of a medium to high agreement with the SPV data for all four individual irrigations. The ICCs of the WAT/DAI comparison were usually smaller. Generally, smaller individual differences were shown in Bland-Altman plots comparing WAI and WAT than plots comparing DAI and WAT. WAI had better subjective tolerability than WAT.

CONCLUSIONS

WAI is an alternative caloric test method for anxious subjects oversensitive to WAT and probably for patients with suspected pathological ear canal and tympanic membrane findings.

Clinical usefulness of the rotatory, caloric, and vestibular evoked myogenic potential test in unilateral peripheral vestibular pathologies

OBJECTIVE

The aim of this study was to investigate the diagnostic capacity of three different rotatory tests, and to investigate the clinical effectiveness of the caloric, rotatory, and vestibular evoked myogenic potential (VEMP) test.

DESIGN AND STUDY SAMPLE

Several rotatory tests--sinusoidal harmonic acceleration test (SHAT), pseudorandom rotation test (PRRT), velocity step test (VST)--and a caloric and a VEMP test, were given to 77 patients (mean age 52 years) with a unilateral peripheral vestibular pathology, and 80 control subjects (mean age 48 years).

RESULTS

For the rotatory test, the highest diagnostic capacity was obtained with the 0.01 Hz SHAT frequency, followed by 0.1 and 0.05 Hz. A higher diagnostic accuracy was reached for the caloric and VEMP test. The caloric test demonstrated high sensitivity and specificity values, but the 0.01 Hz SHAT rotation appeared more sensitive, and the VEMP more specific, than the caloric test.

CONCLUSION

A selection of the 0.01, 0.05, and 0.1 Hz SHAT rotations is suggested as the most ideal rotatory test protocol, and a combination of rotatory, caloric, and VEMP testing will result in a more complete examination of our vestibular system.

The dependency of air caloric stimulus effectiveness on delivery tip characteristics

This brief study investigates the extent and origin of the apparent dependency of air delivery speculum size on the effectiveness of air used as a stimulus in the bi-thermal caloric test, using water as a reference stimulus. Eleven normal volunteers served as subjects. Six caloric stimulus delivery conditions included air with two speculum sizes, speculum only and with a rubber tube extension, and water. The resulting nystagmus was used as an index of stimulus efficiency. The effectiveness of the air stimulus was found to be dependent on the diameter of the speculum used for air delivery. The narrower speculum generated nystagmus that was typically twice that generated by the wider speculum. Users of air caloric equipment whose design includes a speculum that influences the effectiveness of the stimulus should be aware of this dependency and ensure their clinical interpretation of results is made with reference to appropriate normative data.

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

OBJECTIVES

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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