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Stapedectomy and vertigo.

The relationship between vestibular and cochlear function in stapedectomy was investigated in 722 patients (925 ears). There were no differences in hearing between patients with and without pre-operative complaints of vertigo. Post-operatively patients with long lasting vertigo obtained equally good hearing results as the others. The direction of spontaneous nystagmus post-operatively in relation to the operated ear was of no prognostic significance regarding short term hearing results. However, at follow-up an average of 15 years after the operation, hearing was somewhat poorer in those having spontaneous nystagmus towards the operated ear. At follow-up 17% had an abnormal caloric test.

Caloric Tests↗

Database for vertigo.

An interactive database has been developed to assist the diagnostic procedure for vertigo and to store the data. The database offers a possibility to split and reunite the collected information when needed. It contains detailed information about a patient's history, symptoms, and findings in otoneurologic, audiologic, and imaging tests. The symptoms are classified into sets of questions on vertigo (including postural instability), hearing loss and tinnitus, and provoking factors. Confounding disorders are screened. The otoneurologic tests involve saccades, smooth pursuit, posturography, and a caloric test. In addition, findings from specific antibody tests, clinical neurotologic tests, magnetic resonance imaging, brain stem audiometry, and electrocochleography are included. The input information can be applied to workups for vertigo in an expert system called ONE. The database assists its user in that the input of information is easy. If not only can be used for diagnostic purposes but is also beneficial for research, and in combination with the expert system, it provides a tutorial guide for medical students.

Anxiety↗

Screening for retrocochlear pathology.

In 1982, 135 patients were screened for possible retrocochlear pathology, by means of an investigation protocol consisting of caloric test, impedance audiometry and brainstem response audiometry (BRA). A combination of the first two of these procedures had an unacceptably low prognostic accuracy. BRA indicated retrocochlear pathology in 8 and was inconclusive in 4 cases. Enhanced computer tomography revealed an intracranial tumour in 4 of the former, while no space-occupying lesion could be demonstrated in the remainder nor in the 4 patients with inconclusive BRA. BRA is the best single test for screening of this patient category.

Acoustic Impedance Tests↗

[Familial deafness showing hearing pattern of low-tone losses].

Clinical and electrocochleographic studies of low tone familial deafness were carried out in 19 patients of 10 families. These hearing impairments were characterized by an upward-sloping pure tone audiogram with 50dB to 60dB hearing threshold below 2000Hz and with normal or near-normal hearing threshold above this frequency. The type of inheritance in these families showed autosomal dominant mode and no associated malformation. In 7 patients, hearing tests were repeated, it was observed that hearing threshold was not elevated. The short increment sensitivity index (SISI) tests were positive suggesting a hair cell lesion in tested 7 patients. The caloric tests were normal in tested 3 patients. No abnormal internal ear configuration was found in both X-ray and high-resolution computed tomography. Twelve patients with these familial low tone deafness (FLTD), 19 patients with Ménière's disease, and 9 patients with low tone sudden deafness (LTSD) were studied using the transtympanic electrode technique of electrocochleography. All patients of FLTD showed normal negative summating potential (-SP) amplitude, and the cochlear microphonics (CM) showed a nearly same detection threshold as hearing level of the pure tone audiogram at 1 kHz and 0.5 kHz. The evidence suggested that the hearing impairment resulted from a localized abnormality of the cochlear apex, and without endolymphatic hydrops. On the other hand, patients with Ménière's disease and LTSD showed a high -SP amplitude and a satisfactory detection threshold of CM compared with hearing level of the pure tone audiogram. These findings suggest that both Ménière's disease and LTSD relate to endolymphatic hydrops.

Adolescent↗

Unilateral examination of utricle and saccule function.

Attention is directed towards the recently developed unilateral tests of saccular and utricular function. Together with the now widely used head-thrust test and the standard caloric test for semicircular canal function, these provide for a more comprehensive unilateral examination of labyrinth function. The efficacy of vestibular evoked myogenic potentials (VEMP) as a direct unilateral test of saccular function is currently being demonstrated in an increasing number of reports. Furthermore, the relevant neuronal pathways have been delineated in animal studies, so that all evidence points to the validity of the VEMP as a saccule-mediated response. Concerning utricular function, considerable headway has been made using the unilateral centrifugation paradigm. Testing is performed with a variable radius rotary chair with constant velocity rotation about the earth-vertical axis. Displacing the head by 3.5-4 cm from the rotation axis, the eccentrically positioned utricle is stimulated unilaterally by the resultant centrifugal force. This paradigm can be employed to elicit a utriculo-ocular response (UOR) or to permit measurement of the subjective visual vertical (SVV). More recently, it has also been demonstrated that testing during normal, on-centre yaw axis rotation is often sufficient to localise peripheral otolith dysfunction by means of SVV estimation. This test mode can be easily integrated into routine clinical testing. To illustrate the efficacy of such differential testing, the findings from two patients are presented that demonstrate for the first time an isolated unilateral utricular dysfunction.

Animals↗

Audiovestibular results after surgery for cerebellopontine angle meningiomas.

Meningiomas are the second most common cerebellopontine angle (CPA) tumor. The reported rates of hearing preservation following surgical removal vary between 32% and 100%. There is only one recent report discussing vestibular function after CPA meningioma removal. In this series of 31 patients with CPA meningiomas, 16 patients had their tumors removed via the retrosigmoid approach. All 16 had audiovestibular assessment pre- and postsurgery and were the subjects of this study. Class A hearing is socially useful hearing and is defined as a pure tone average (PTA; average of 500 Hz and 1, 2 and 4 kHz) of < 30 dB and speech discrimination scores (SDS) of > 70%. Class B hearing is serviceable hearing, defined as PTA of < 50 dB and SDS of > 50%. Nine patients had class A hearing, and two had class B hearing presurgery. Socially useful hearing was preserved in six of nine (67%) patients in whom it was present before surgery, and serviceable or better hearing was preserved in eight of 11 (73%). Vestibular symptomatology and examination findings improved despite a decrease in the number of patients with intact caloric function postsurgery. Patients who retained vestibular function on caloric testing were symptomatically better than those who lost caloric function. These results confirm that excellent audiovestibular function is possible after CPA meningioma surgery.

Adult↗

[Clinical application of the visual suppression test].

200 cases of peripheral and central vestibular disorder patients were examined by caloric test and visual suppression test (VS) simultaneously. The results with ENG recording showed: (1) VS score > 50% indicates normal function. (2) VS score 50%-10% is function decreased. (3) VS score < 10% shows function failure. (4) Patients with negative VS score accompanies nystagmus strengthen with eye open when in the light also, the clinical application of the VS test for diagnosis of several kinds of vestibular disorder were discussed.

Acoustic Stimulation↗

Audio-vestibular disturbances in Behcet's patients: report of 62 cases.

UNLABELLED: This study was carried out to determine the characteristics and incidence of hearing loss and vestibular disturbance in Behcet's syndrome with a large number of patients. Sixty-two patients with Behcet's syndrome were included in this study, 34 men and 28 women whose mean age was 33.7 (15-60). Sixty-two healthy normal control subjects (38 male and 24 female) were included. Patient and control groups were questioned about any history of audio-vestibular disturbance and underwent physical and ENT examination and the following audiologic tests: pure tone audiometric test (0.25, 0.5, 1, 2, 4, and 6 kHz), tympanogram, speech discrimination, short increment sensitivity index, tone-decay test, auditory brainstem response. Vestibular system was evaluated by videonistagmogram and caloric test. Cranial and brainstem magnetic resonance imagine (MRI) of patients who have vestibular disturbances were practiced to examine the central nervous system. Both the patient and the control groups were tested with the HLA-B51 antigen. Pure tone audiogram showed sensory-neural hearing loss (25 dB hearing level in at least two frequencies) in 20 of the 62 (32%) Behcet's patients while the control group were normal. There was a hearing loss involving high frequencies in the audiograms of Behcet's patients with hearing disturbances. The recruitment investigation tests and auditory brain stem response confirmed cochlear involvement in all 20 patients. Caloric stimulation tests revealed a normal vestibular function in all patient and control group. In electronystagmography, 21 (34%) patients had hypometric or hypermetric saccades and smooth pursuit tests showing that 4 (6%) patients had pathological changes while the control group was normal. HLA-B51 antigen was found positive in 15 of 20 Behcet's patient with hearing loss. CONCLUSION: (1) The hearing and vestibular disturbances in Behcet's syndrome is more prevalent than previously recognized; (2) Hearing loss in high frequencies in Behcet's patients is an indicator of cochlear involvement in this disease; (3) There is a higher prevalence of central vestibular syndrome in Behcet's patients than it was thought before; (4) HLA-B51 antigen may be able to be a prognostic factor for sensorineural hearing loss in Behcet's patients.

Adolescent↗

Changes in the human vestibulo-ocular reflex after loss of peripheral sensitivity.

Quantitative rotational testing was used to study changes in the vestibulo-ocular reflex of patients with unilateral and bilateral peripheral vestibular lesions. Compared with normal subjects, the patients exhibited a characteristic pattern of decreased gain and increased phase lead at low frequencies of sinusoidal stimulation and decreased time constants on impulsive stimulation. By contrast, gain and phase measurements on high-frequency-low-amplitude sinusoidal stimulation were often normal. In the patients with bilateral lesions, the results of caloric testing correlated with the results of low-frequency rotational testing but not with the results of high-frequency testing. There are two main clinical implications of these findings. First, patients with absent response to caloric stimulation (unilateral or bilateral) may have a normal response to high-frequency sinusoidal rotation (i.e., the frequencies that constitute most natural head movements). This probably explains why such patients do not report oscillopsia. Second, low-frequency sinusoidal rotational testing and caloric testing are more sensitive than high-frequency sinusoidal or impulsive rotational testing for detecting early loss of vestibular sensitivity due, for example, to ototoxic drugs.

Adult↗

Vestibular diagnosis in Menière's disease.

Vestibular diagnosis of Menière's disease must be based on the results of an elaborate test battery. The latter should include a complete caloric test (stimulation with cold and warm water), carried out under nystagmographic control. Statistical analysis of caloric responses recorded in 100 normal test subjects by D.C. nystagmography show clearly that culmination frequency and culmination eye velocity are the most reliable parameters indicating an unilateral loss of function. With respect to the differential diagnosis - endorgan or neuronal lesion - only the galvanic test allows an unequivocal localisation of the site of the lesion. An analysis of 50 cases of Menière's disease reveals normal liminal and supraliminal galvanic responses without exception, thus indicating that the concomitant reduced caloric response is due to a lesion strictly confined to the vestibular endorgan. Hence the galvanic test may serve the same diagnostic purposes as supraliminal tests in pure tone audiometry.

Caloric Tests↗

Caloric nystagmus decay during parabolic flight.

In human subjects the caloric test was conducted during parabolic flight. The slow-phase velocity (SPV) of the caloric nystagmus increased proportionally to the value of the g-force. The nystagmus disappeared in microgravity, after an exponential SPV decay that showed a specific time constant (Tc). The average Tc value of this SPV decay is on a lower level than the one found after a sudden stop-test in the laboratory in a 1-g condition. Because of the exponential characteristics of the SPV decays and their Tc values, evoked in both conditions, a common working mechanism of cupular stimulation is likely. Most probably a fluid movement, caused either by a sudden stop in a 1-g condition or by weightlessness after a calorization, provokes a cupula flexion followed by a reflexion. The results support the Bárány convection theory with regard to the endolymph movement following the caloric test.

Caloric Tests↗

[Disability in patients with benign paroxysmal positional vertigo with posterior semicircular canal involvement].

OBJECTIVE: The aim of this work is to analyze the vestibular function and level of disability in two populations of patients with positional vertigo but with different results in the Dix-Hallpike test. MATERIAL AND METHODS: 114 patients were assessed. In 65 the Dix-Hallpike test was positive (DH+) and in 49 negative (DH). The caloric test was performed as well as the assessment of disability with the pertinent questionnaires for vestibular disability. RESULTS: Patients in the DH+ group showed a higher level of disability in the physical subscale of the DHI and a higher perception of a deteriorated quality of life. Patients in the DH- group showed a more severe disability in the emotional subscale of the DHI. CONCLUSIONS: Once the phenomenon of nystagmus fatigability is ruled out, patients with positional vertigo and DH- must not be considered a minor form of positional vertigo.

Adult↗

Body position and caloric nystagmus response.

The observation that the caloric nystagmus response is dependent on body position has been repeated in several studies during the course of this century. For many, this position-dependent modulation of the caloric response has been interpreted as evidence in favour of the thermoconvection theory as originally proposed by Bárány. However, the adequacy of this theory has been put into question by recent observations of caloric nystagmus during weightlessness in orbital flight. These zero-g findings clearly demonstrate that any hypothesis based on thermoconvection alone must prove insufficient as a description of the caloric nystagmus response. In the light of these recent findings, it has also become necessary to reconsider the influence of body position on caloric nystagmus intensity and the physiological mechanisms involved. Caloric testing was performed with a group of 30 healthy test subjects. Each person was tested in eight different body positions in the sagittal plane. Caloric nystagmus response was registered by means of horizontal and vertical EOG. The observed modification of the caloric response (SPV) by assumed body position is discussed with reference to associated reports in the literature.

Adult↗

Site of lesion vestibular function testing.

The results of conventional electronystagmography (ENG) sometimes are confusing. The Hallpike alternate binaural bithermal (ABB) caloric test is helpful diagnostically except for the group of "sick patients that have a normal test." Conventional ENG tests also fall short in the area of objective confirmation of patient progress. What does each test tell us regarding site of lesion? 1. Alternate binaural bithermal stimulation gives us information about the semicircular canals -- particularly the horizontal semicircular canal -- pickup head. 2. Simultaneous binaural bithermal stimulation gives information brain stem connections -- switching and relay. 3. Rotation testing gives information about the processing by the brain -- central control.

Adult↗