Integrated clinical and laboratory vestibular evaluation:

A New Proposal for Severity Evaluation of Menière's Disease by Using the Evidence From a Comprehensive Battery of Auditory and Vestibular Tests

To date, no widely accepted criteria exist to quantify the severity of Menière's disease (MD) by using vestibular tests. This study aimed to compare association of hearing loss and vertigo severity with association of accurate assessments of vestibular function and the vertigo severity. The severity of vertigo was documented by a comprehensive medical history with number of vertigo attacks in the past 6 months and a Dizziness Handicap Inventory (DHI) questionnaire. The involvement of vestibular organs was verified by audio-vestibular tests in 80 definite MD patients. Correlations between DHI scores, number of vertigo attacks in the past 6 months, audio-vestibular function, and the number of involved vestibular end organs were evaluated. We show that there are no significant differences in either severity of vertigo or laboratory results across the degree of hearing loss. Furthermore, the number of involved vestibular end organs was significantly correlated with vestibulo-ocular reflex gain in anterior and posterior canal video head impulse test (vHIT), interaural asymmetry ratio in vestibular-evoked myogenic potentials (VEMPs), and number of vertigo attacks in the past 6 months and DHI score. The vestibulo-ocular reflex gain in the rotatory chair test (RCT) was significantly correlated with the DHI Physical scores and number of involved vestibular end organs at 0.08 Hz. These results indicate that hearing loss is a poor indicator of vertigo severity in MD whereas the number of involved vestibular end organs may serve as an objective measure for MD progress. A battery of vestibular tests targeting different sensor organs is a complementary method for evaluating inner ear deficits and may aid in "grading" the severity of MD.

Prevalence of hearing and vestibular loss in cystic fibrosis patients exposed to aminoglycosides

AIM

Cystic Fibrosis (CF) patients frequently use aminoglycosides (AGS) to treat CF exacerbation due to colonization with Pseudomonas aeruginosa. Although AGS can cause vestibular and auditory sensory losses that can negatively impact quality of life, little is known about the prevalence of vestibular loss in this population. The aim of this study was to determine the prevalence of hearing loss and/or vestibular dysfunction in CF patients treated with AGS.

METHODS

The relationship between hearing status and vestibular status was also investigated. Hearing was determined to be normal or abnormal based on pure tone air and bone conduction thresholds. Vestibular outcome was divided into four categories; normal, non-lateralized vestibular dysfunction, unilateral loss, and bilateral loss based on results of post head shaking testing, positional and positioning testing, bithermal calorics, sinusoidal, and rotational step testing.

RESULTS

Of our cohort of 71 patients, 56 (79%) patients have vestibular system dysfunction while only 15 (21%) have normal vestibular system function. Overall, 16 patients (23%) have hearing loss. In considering the relationship between auditory and vestibular function, 12 (17%) demonstrated both normal hearing and normal vestibular function and 13 (18%) have both hearing loss and abnormal vestibular function. Of the 55 (78%) patients with normal hearing, 43 (61%) have vestibular dysfunction, while 3 (4%) of patients with normal vestibular function have hearing loss.

CONCLUSION

These results suggest that monitoring hearing alone is insufficient to detect ototoxicity in CF patients being treated with systemic AGS.

Intranasal scopolamine affects the semicircular canals centrally and peripherally

Space motion sickness (SMS), a condition caused by an intravestibular conflict, remains an important obstacle that astronauts encounter during the first days in space. Promethazine is currently the standard treatment of SMS, but scopolamine is used by some astronauts to prevent SMS. However, the oral and transdermal routes of administration of scopolamine are known to have substantial drawbacks. Intranasal administration of scopolamine ensures a fast absorption and rapid onset of therapeutic effect, which might prove to be suitable for use during spaceflights. The aim of this study was to evaluate the effects of intranasally administered scopolamine (0.4 mg) on the semicircular canals (SCCs) and the otoliths. This double-blind, placebo-controlled study was performed on 19 healthy male subjects. The function of the horizontal SCC and the vestibulo-ocular reflex, as well as the saccular function and utricular function, were evaluated. Scopolamine turned out to affect mainly the SCCs centrally and peripherally but also the utricles to a lesser extent. Centrally, the most probable site of action is the medial vestibular nucleus, where the highest density of muscarinic receptors has been demonstrated and afferent fibers from the SCCs and utricles synapse. Furthermore, our results suggest the presence of muscarinic receptors in the peripheral vestibular system on which scopolamine has a suppressive effect. Given the depressant actions on the SCCs, it is suggested that the pharmacodynamic effect of scopolamine may be attributed to the obliteration of intravestibular conflict that arises during (S)MS.

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.

Diagnosis and management of dizziness and vertigo

Dizziness and vertigo present in patients of all ages. Particularly in older patients, dizziness is associated with a variety of cardiovascular, neurosensory, and psychiatric conditions and with the use of multiple medications. For the patient, the symptoms can be debilitating. In patients older than 60 years, 20% have experienced dizziness severe enough to affect their daily activities. Appropriate diagnosis and treatment can significantly improve quality of life. Most causes of dizziness are benign, but early recognition of serious or life-threatening disease is important. Management of these patients includes referral for neuroimaging and further evaluation in an emergency department.

Symptomatic high frequency/acceleration vestibular loss: consideration of a new clinical syndrome of vestibular dysfunction

CONCLUSION

Symptomatic high frequency/acceleration vestibular loss is a distinct clinical entity that can be missed on conventional ENG with caloric testing. Under certain circumstances, symptomatic patients with a high frequency/acceleration vestibular loss should undergo an MSSC study for confirmation, if required.

OBJECTIVE

To document that normal electronystagmography (ENG) with conventional bithermal caloric testing is inadequate for diagnosing clinically significant high frequency/acceleration vestibular loss.

MATERIAL AND METHODS

Patients with clinical symptoms and signs of persistent peripheral vestibular dysfunction despite normal conventional bithermal caloric testing on ENG underwent high frequency/acceleration horizontal magnetic scleral search coil (MSSC) eye movement studies. The clinical findings and results from audiometric tests, conventional ENG with bithermal caloric tests and MSSC tests were reviewed.

RESULTS

Eleven patients were identified as having an abnormal MSSC study, indicating a high frequency/acceleration vestibular loss consistent with their clinical history despite normal or equivocal bithermal caloric responses on conventional ENG. Although valuable, ENG caloric testing evaluates lateral semicircular canal function and should be considered a non-physiological test primarily of low frequency vestibular function. High frequency/acceleration head thrust testing clinically detected a "high frequency/acceleration vestibular loss" in 8/11(72.7%) cases.

Vestibular neuronitis in pilots: follow-up results and implications for flight safety

OBJECTIVES To report our experience over the past 12 years with the evaluation and follow-up of pilots with vestibular neuronitis and to discuss points relevant to flight safety and the resumption of flying duties. STUDY DESIGN A retrospective, consecutive case series.METHODS Eighteen military pilots with vestibular neuronitis were examined and followed up. A complete otoneurological workup was performed, including both physical examination and laboratory evaluation. The latter included electro-oculography (EOG) and a rotatory chair test using the smooth harmonic acceleration protocol. RESULTS The mean patient age was 35 +/- 6 years (range, 23 to 42 y), and the average follow-up period was 20.5 +/- 12.8 months (mean +/- standard deviation [SD]; (range, 11 to 48 mo). Electro-oculography caloric test on presentation documented significant unilateral hypofunction in all patients. Thirteen of the 18 patients (72%) had abnormal smooth harmonic acceleration test results. None of the pilots reported any symptoms on follow-up. However, five (28%) had positive otoneurological examination findings, and eight (44%) still had significant caloric lateralization (>25%). The average caloric hypofunction was reduced from 67.8% +/- 29.3% at onset to 40% +/- 16% (mean +/- SD, <.05, paired test). Seven of the patients (39%) had additional electro-oculography findings beyond caloric hypofunction. These included spontaneous, positional, and positioning nystagmus. Smooth harmonic acceleration disease on follow-up was documented in eight patients (44%), five of whom had canal paresis. Eleven patients (61%) demonstrated residual vestibular damage on follow-up. In 6 of these 11 cases (55%), the laboratory evaluation revealed vestibular deficits otherwise undiagnosed by the bedside test battery. CONCLUSIONS The vestibular system plays a central role in orientation awareness and is often challenged by flying conditions. The finding that approximately 60% of pilots who have had vestibular neuronitis continue to show signs of vestibular malfunction, despite apparent clinical recovery, emphasizes the need for a complete vestibular evaluation, including specific bedside testing and laboratory examinations, before flying duties can be resumed.

The assessment and management of the dizzy patient

A significant number of individuals are affected by symptoms of dizziness. It is the most common complaint among patients over 75 years of age. A large number of these patients seek counsel from their physicians. It is imperative for the evaluating physician to obtain a thorough history and perform a complete physical exam. The proper diagnostic studies must also be obtained to confirm or rule out particular diagnoses. The physician should never assume that the dizziness is the result of normal aging prior to ruling out pathologic conditions.