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PubMedDate not supplied

Evaluation of multiple-frequency rotatory testing in patients with peripheral labyrinthine weakness.

Multiple-frequency rotatory testing was performed in a series of 12 normal subjects and 27 patients who had significant labyrinthine paralysis. Fourteen of the patients had total loss of labyrinthine function. Phase leads of the responses were much greater in the lower-frequency measurements and measured gains of the responses to ampullopetal stimulation were qualitatively greater than those of the responses to ampullofugal stimulation. However, many patients' responses continued to fall within the normal range because of the large variability of the responses of normal subjects. The value of rotatory testing in clinical diagnosis is discussed.

Caloric Tests↗
PubMed1995

Evaluation of the human vestibulo-ocular reflex at high frequencies with a helmet, driven by reactive torque.

A new technique was developed to test the VOR in humans. A tightly but comfortably fitting helmet was provided with an electronically controlled torque motor that rotated a mass around a vertical axis. Acceleration of the motor caused reactive torque of the helmet in the opposite direction which was transmitted to the (freely movable) head. Sinusoidal head oscillations in the frequency range 2-20 Hz (peak-to-peak amplitudes about 10 degrees and 0.1 degrees respectively) were easily achieved, as well as step displacements of the head with accelerations on the order of 1000 degrees/s2. Limitation of the maximum torque and lack of any rigid attachment of the head to a fixed structure made the technique safe and comfortable. Eye and head rotations were recorded, independently of head translations, with eye and head search coils in a homogeneous a.c. magnetic field. In normal subjects, gain was near unity at 2 Hz: above 8 Hz, gain increased progressively toward 1.1-1.3 at 20 Hz. Phase lag increased from a few degrees at 2 Hz to about 45 degrees at 20 Hz. Above 2 Hz, these results were unaffected by visual conditions; lower gains and increased phase lags were found in subjects with bilateral or unilateral vestibular loss. For step displacements, gain (measured in the first 100 ms) was near unity for normals, near zero after bilateral vestibular loss and strongly asymmetrical after unilateral vestibular loss. Thus, the technique seems highly effective in testing vestibular function with minimal contamination by other systems.

Acceleration↗
PubMed1977

[Clinical comparison of perrotatory and postrotatory nystagmus characteristics (author's transl)].

Rotatory stimulation is a physiological stimulation of the vestibular canalicular organs. In every day's neurootological routine it is applied in sinusoidal, triangular and trapezoidal shape. The rotatory intensity damping test (RIDT) applies a perrotatory and postrotatory test combination of a trapezoidal stimulus pattern. Thus the perrotatory as well as the postrotatory nystagmus can be recorded during several phases of the after phenomena. In terms of acceleration/time plots the supraliminal perrotatory acceleration exhibits a rectangular or step-like stimulus characteristic. The supramaximal postrotatory stimulus however has a needle-like impulse pattern. The nystagmus reaction being recorded by the ENG is evaluated according to frequency or beat-rate distributions. The perrotatory nystagmus can be linearily optimalized in a linear to linear plot during its maximal reactional dynamics. The postrotatory nystagmus distribution can also be linearily graphed in a nomogram. However this nomogram is a log.log intensity/time-chart. This paper clinically compares per- and postrotatory reactions of the rotatory intensity damping test. It can be seen that this test adds important information to the clinical study of the dizzy patient.

Adult↗
PubMed2006

Study of vestibular evoked myogenic potentials in unilateral vestibulopathy: Otolithic versus canal function testing.

OBJECTIVE: The study provides a qualitative evaluation of unilateral vestibulopathy by comparing otolithic and canal function, to establish possible relationships between the type of dysfunction observed and the evolving clinical pictures associated with it. STUDY DESIGN: Retrospective study of a series of cases. SETTING: Department of Medical-Surgical Specialization, Otolaryngology and Cervicofacial Surgery Division, University of Perugia, Perugia, Italy. PATIENTS: Twenty patients whose medical history showed at least one episode corresponding to the clinical parameters of acute vestibulopathy. INTERVENTIONS: Study of vestibular function by recording VEMPs and repeating canal function testing at least 6 months after the first episode of vertigo. MAIN OUTCOME MEASURES: Relationship between the type of vestibulopathy (canal and otolithic) and the clinical pictures observed. RESULTS: Paroxysmal positional vertigo, observed in 4 patients, was correlated with the presence of vestibular evoked myogenic potentials (VEMPs) and the absence of an ipsilateral canal response in all cases (100%). Persistent dizziness was observed in nine patients, and VEMPs were absent in all of them (100%); three (33.3%) showed the recovery of previously absent canal function. Comparison of responses in six patients with recurrent acute vestibulopathy showed persistent and complete loss of canal function in five cases (83.3%), whereas impairment of otolithic response was less constant (40%). CONCLUSION: The combined VEMPs-canal test study shows predictive value regarding certain evolving clinical pictures of vestibulopathy. The absence of VEMPs confirms the role of otolithic dysfunction in the onset of dizziness. Likewise, it suggests that a vestibular origin of these disorders should be considered in cases that have shown aspecific symptoms since onset, without frank vertigo and with normal vestibular response to canal function testing.

Adult↗
PubMedDate not supplied

Hearing preservation in acoustic neurinoma surgery.

In a series of 120 patients with acoustic neurinoma, hearing preservation at removal of the tumour via the suboccipital approach was attempted in 30 ears. Hearing was preserved in 13 ears (43%), but in two, hearing was lost entirely in 3 to 4 years; thus the success rate was 36%. In 9 of the remaining 11 ears useful speech discrimination was present. Audiological tests showed increased retrocochlear loss after surgery. A surgical team should master the methods of both translabyrinthine and suboccipital surgery in order to choose the best approach for each patient.

Acoustic Impedance Tests↗
PubMedDate not supplied

[Correlation between audiometric and electronystagmographic results in Menière's disease].

Cochlear and vestibular functions of 30 patients suffering from Méniere's disease have been analyzed through audiometric and electronystagmographic studies. Auditive thresholds in low, medium and high frequencies have been correlated with the results of the caloric and pendular tests. Statistical analysis has demonstrated that there is no significant relationship between caloric and pendular reflectivity and hearing loss in the mentioned frequencies. In conclusion, in Méniere's disease hearing losses and vestibular alterations follow a different pathologic pattern.

Adult↗
PubMed1996

Classification of human rotation test results using parametric modeling and multivariate statistics.

The usefulness of vestibular testing is directly related to the accuracy of the test interpretations. Two factors, subjective analysis of large test data sets and failure to make appropriate age corrections, tend to reduce test accuracy. Correction of these problems can be accomplished by application of physiologically based models of vestibular function and multivariate classification techniques to the test data, thereby creating a more objective test interpretation procedure. Herein we report our results on the use of this strategy for analysis of sinusoidal harmonic acceleration (SHA) test interpretation. For each patient, models reduce the large set of SHA test variables to three key parameters: asymptotic gain, vestibulo-ocular reflex time constant, and bias. In addition, the new technique objectively adjusts these parameters for the patient's age. Finally, each patient's set of parameters are statistically classified as either normal or as unilateral peripheral deficit. Based on learning sets of 57 normals and 30 patients with a full unilateral peripheral deficit, this new technique resulted in a misclassification rate between the categories of normal and full unilateral loss of 3.4%, comparing favorably to the present method's misclassification rate between normal and abnormal of 13.8%. We also analyzed and classified a test group consisting of patients with possible partial unilateral deficits using the same classification function as the normal and full unilateral learning sets. Even though the classifier was not optimized for the partial group, results seemed favorable relative to the human interpreter. These results validate the accuracy and utility of physiological parametric models and multivariate statistical classification in SHA test interpretation.

Acceleration↗
PubMedDate not supplied

Vestibular investigations in Meniere's disease.

151 patients with unilateral Meniere's disease were investigated with a vestibular test battery in the interval between vertigo attacks, and the results were compared with those obtained in a control group. In 73.5% of the patients a caloric response reduction of the afflicted ear was observed. The mean caloric response reduction was 34.3%; a major response reduction or a total absence of the caloric response of the afflicted ear was rare. A correlation was found between the amount of caloric response reduction and the duration of the disease. Spontaneous nystagmus was found in 47% of the cases (mean value 3 degrees/sec) and a mainly direction fixed positional nystagmus in 78% (mean value 4.0 degrees/sec). No correlation was found between the mean hearing loss and the magnitude of caloric response reduction on the day of investigation.

Adolescent↗
PubMed2002

Evaluation of vestibular function in young children.

Together, these tests provide a full evaluation of vestibular function in infants and small children. If attention is paid to creating the appropriate testing environment, and interpretation of the tests takes into account the unique properties of the responses of infants and young children, this testing can provide a useful adjunct to audiometric evaluation in young children.

Caloric Tests↗
PubMed1988

Neurotological findings in Bell's palsy and Hunt's syndrome.

Neurotological findings were analysed in 23 patients with Bell's palsy and in 25 patients with Hunt's syndrome. The incidence and extent of the auditory and vestibular pathology was high in Hunt's syndrome. Although patients had no subjective symptoms related to the auditory and/or vestibular pathology in the Bell's palsy cases, about one-third of the patients showed abnormal findings upon neurotological examination. Differentiating these two diseases is therefore considered difficult by means of neurotological examination in the same way as by serological testing as has been reported by other investigators.

Audiometry, Pure-Tone↗
PubMed1991

Strategy for the diagnosis of small acoustic neuromas.

Twenty small (extra-meatal size less than 15 mm) acoustic neuromas have been diagnosed since high-resolution (HR) magnetic resonance imaging (MRI) became available in our clinic. Among these tumors, 18 had sensorineural hearing loss and 16 enlarged internal auditory meatus in X-ray photo, but only 8 tumors out of 18 tested showed diminished caloric response. Auditory brainstem responses (ABR) has been believed as the most reliable test for the diagnosis of acoustic neuroma despite several reports of false-negatives. In our series, 4 tumors out of 18 tested had normal ABR. The false-negative rate was 22%, which is much higher than expected. In CT, only 11 tumors were recognized. Although the total number is not large, present results clearly suggest the limits of these examinations. At present, HR-MRI is the most reliable diagnostic method for acoustic neuromas with no false-negative reported; ordinary MRI may have false-negatives. For the effective use of MRI, the results of audiometry, X-ray photo, ABR and other examinations must be evaluated properly.

Audiometry↗
PubMed1985

Assessment of intestinal and cardiorespiratory function in children with congenital heart disease on high-caloric formulas.

Fourteen infants with congenital heart disease were investigated for failure to thrive. Assessment of intestinal function revealed minor absorptive abnormalities (mild steatorrhea in three patients, bile salt loss in four patients), delayed gastric emptying, and abnormal triglyceride loading tests. Low caloric intake (88.3 +/- 19.3 kcal/kg/day) seemed the main reason for failure to gain weight. Weight accession and cardiorespiratory rates were monitored daily during voluntary intake, a high-caloric diet by mouth, and nasogastric tube feeding. Providing 169 +/- 29 kcal/kg/day by tube resulted in weight gain with mild and transient elevation of respiratory rate at the end of the meal and increased heart rate 90 min after the meal. This regimen is a metabolically inexpensive and efficient method of supporting weight gain in children with congenital heart disease.

Age Factors↗
PubMed1999

Central nervous system impairment in diabetic patients.

The aims of this study were to investigate the function of the central motor control system in interaction with the vestibular and auditory systems (measured by H-reflex changes in response to vestibular and acoustic stimulations) in diabetics without clinical data for CNS impairment, in order to establish whether the disease affects these CNS mechanisms; and to assess this approach in detecting subclinical CNS diabetic pathology. The results show the same mode of change of H-reflex amplitude in response to acoustic and vestibular stimulations in diabetics as in normal subjects. However the degree of facilitation and inhibition was significantly (p < 0.001) higher in diabetics which indicates subclinical CNS dysfunction. Therefore it was concluded that the test is useful in early diagnosis of the diabetic CNS impairment.

Acoustic Stimulation↗
PubMedDate not supplied

Testing of vestibular function: an adjunct in the assessment of chronic fatigue syndrome.

Patients with chronic fatigue syndrome (CFS) often complain of dysequilibrium that is nonspecific. The basis of this complaint is unknown but may be related to vestibular system abnormalities, in that an association between inner-ear deficits and infectious mononucleosis has been established in the medical literature. An overview of quantitative vestibular function testing is given, including vestibulo-ocular and vestibulospinal tests. The basic principles of caloric and rotational testing are provided, including the interaction between vision and the vestibular system. Moving-platform posturography is described. Preliminary results from quantitative vestibular function testing of a small group of individuals with CFS are provided.

Fatigue Syndrome, Chronic↗
PubMed1979

Some critical remarks on the interpretation of vestibular test results.

In the scope of the evaluation of vestibular function, the attention is drawn to the fact that results of tests are to be considered in a relative way. They do not express the absolute functional capacity, but in half of the cases it can be shown that the functional state is intensity dependent. This can be observed in claoric tests as well as in rotation tests. In these latter even the type of stimulation may give a different result. The experiences obtained in a number of cases by both stimulation types confirm this assessment that the functional result is always to be considered in this relative way. This implies some reserves as to the comparability of results of various authors, using different stimulation schemes. On the other hand, and this especially in rotation tests, application of more stimulation intensities allows to separate cases with stable from those with labile results.

Caloric Tests↗