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PubMed1984

A simple and time saving cold mini caloric test.

A simple and time-saving office procedure is presented. The test consists of placing a small piece of cotton-wool soaked in ice water against the tympanic membrane. We term this test the Cold mini caloric test. Our method has been compared quantitatively with the Bithermal caloric test in 20 normal controls, 50 unspecific dizzy patients with no vestibular or obvious neurological disorder, 22 Menière ears, 12 acoustic neuromas and 20 cases of vestibular neuronitis. The comparison between the two methods has shown the Cold mini caloric test to present consistently similar, though somewhat shorter, nystagmic reactions. There was no difference in the clinical information obtained by the two methods.

Caloric Tests↗
PubMed1977

[The diagnostic value of the Stepping Test of Unterberger (author's transl)].

Of the vestibulo-spinal reactions, the "stepping test" is considered to be the most important, especially for unilateral peripheral vestibular disturbances. Electronystagmography was performed on seven patients after transtemporal neurectomy of the vestibular nerve, 17 patients with a nearly compensated vesitbular defect after vestibular neuronitis, and seven patients after suboccipital removal of acoustic neuromas. These results were then compared to the spontaneous stepping test. The test could not be performed on six of the seven patients with the operated acoustic neuroma, and on three other patients. The test was positive in only ten of the other 22 patients. It was incorrect in five patients and equivocal in seven. A reliable spontaneous vestibulo-spinal reaction with nearly compensated peripheral vestibular defects could not be determined during the present study.

Adult↗
PubMed1981

Harmaline-induced tremor. II. Unit activity correlation in the interposito-rubral and oculomotor systems of cat.

Units were recorded extracellularly in the cat brainstem under the effect of tremogenic doses of harmaline. They were localized post mortem and the units discharging at the harmaline tremor frequency were mapped. Harmaline-sensitive neurons were found in the bulbo-pontine reticular formation, in particular, in the lateral reticular nucleus and the nucleus reticularis tegmenti pontis. The nucleus interpositus as well as the red nucleus also displayed numerous units discharging at the tremor frequency, indicating that the cerebello-interposito-rubro-spinal system controlling the flexor muscles participate in harmaline tremor. Participation of the oculomotor system in the harmaline-induced tremor was tested at the level of the vestibular neurons relaying the vestibulo-ocular reflex, the motoneurons, the eye muscles and the eye movements. No rhythmic discharge at the tremor frequency nor eye movements could be detected, indicating that harmalie tremor does not affect the oculomotor system.

Alkaloids↗
PubMed1993

Vestibular control of skeletal geometry in the guinea pig: a problem of good trim?

Motor control of different segments of the body with multiple degrees of freedom appears to be coordinated by utilizing preferred axes of motor activity. This hypothesis may also be applied to vestibular control of posture. To explore this question we studied the anatomical relationship between the head and the cervical vertebral column by taking radiographs of the head-neck region in unrestrained alert guinea pigs. We determined that biomechanical constraints contribute to the stereotypical skeletal geometry observed in the resting animal and to a functional segmentation of the head-neck movement apparatus. Subsequent lesion studies of vestibular end organs with quantification of the resulting postural syndromes suggest that the functional segmentation of the cervical vertebral column corresponds to a functional partitioning of vestibular afferents. Our findings also indicate that the sensorimotor transformation mechanisms necessary to convert a given head velocity signal into the appropriate neck motor frame are already embedded in the networks provided by second-order vestibular neurons. Good trim of postural control will be the end result of an appropriate internal representation of the objective vertical.

Afferent Pathways↗
PubMed1994

Polyamine changes in the vestibular nuclei of guinea pigs following labyrinthectomy.

Vestibular compensation is a process of behavioral recovery from ocular, motor and postural disorders following unilateral damage to the vestibular end-organ. Although restoration of the normal resting discharge rate in the ipsilateral vestibular nuclei is important in compensation, the biochemical and molecular mechanisms mediating recovery are largely unknown. The ornithine decarboxylase polyamine pathway is activated in the nervous system following axotomy or denervation. The authors postulate that changes in polyamines mediate vestibular compensation. Within 150-micron brain stem coronal section micropunches analyzed by high performance liquid chromatography techniques, the polyamine spermidine was significantly increased in the ipsilateral lateral vestibular nucleus 8 hours following labyrinthectomy in the guinea pig model. Because naturally occurring polyamines modulate excitatory amino acid receptors (N-methyl-D-aspartate [NMDA]) which in turn mediate neurotransmission between primary afferents and second order vestibular neurons, stimulation of polyamine pathways following neural injury may play a critical role in compensation.

Amino Acids↗
PubMed1989

The abducens motor and internuclear neurons in the rabbit: retrograde horseradish peroxidase and double fluorescent labeling.

Horseradish peroxidase and the fluorochromes Fast blue and propidium iodide were injected into the lateral rectus and retractor bulbi muscles and/or the oculomotor nucleus of the rabbit to determine the locations and basic morphology of motoneurons and internuclear neurons in the abducens nucleus. The 1000-1100 motoneurons found were distributed throughout the nucleus except in the rostral and caudal tips, but were most densely clustered in the dorsomedial area, especially in the middle third of the nucleus, where 60% of these cells were found. The rostral and caudal tips were composed of internuclear neurons, 25% of which lay in the rostral third of the nucleus, 35% in the middle third and 40% in the caudal third. In the middle third, interneurons occupied the ventral and lateral areas of the nucleus (where they mingled with motoneurons); in the rostral and caudal thirds they were more widely distributed. At the level of the caudal half of the nucleus it was impossible to distinguish clearly between the most lateral abducens interneurons and the most rostromedial labeled vestibular neurons. The abducens interneurons of the rabbit (320-380) thus differ in interesting respects from those described previously in either lateral eyed or frontal eyed mammals.

Abducens Nerve↗
PubMed1988

Recovery from unilateral labyrinthectomy in rhesus monkey.

1. We recorded eye movements in six rhesus monkeys before and after unilateral labyrinthectomy and quantified the compensation for both the static and the dynamic disturbances of the vestibuloocular reflex (VOR). 2. When first recorded after labyrinthectomy (18-20 h postlesion), all animals had a spontaneous nystagmus with mean slow-phase velocities ranging from 24 to 54 degrees/s measured in darkness and 0-4 degrees/s measured in the light. The level of nystagmus diminished quickly, and by postoperative day 25 mean values ranged from 4 to 22 degrees/s, measured in darkness. The waveform of individual slow phases was variable, but in the first postoperative week its trajectory usually showed an increasing, or an increasing then decreasing, velocity. This finding indicates that peripheral vestibular lesions can alter the function of the ocular motor eye-position integrator. 3. The VOR gain (eye velocity/head velocity, corrected for spontaneous nystagmus) during rotations (30-300 degrees/s) in the dark was diminished from nearly 1.0 preoperatively to approximately 0.5 when first measured after labyrinthectomy, except for rotations toward the lesioned side at high speeds for which the gain was even lower. Within the first few postoperative days, for rotations toward the intact side, the VOR gain increased rapidly, to approximately 0.8. For rotations toward the lesioned side similar behavior was noted for stimuli of 30-60 degrees/s, but at higher velocities compensation proceeded more slowly. By 3 mo postoperatively gains had reached values ranging from 0.77 to 1.03 for rotations toward the intact side and from 0.61 to 0.98 for rotations toward the lesioned side. Values were higher for lower-velocity stimuli. 4. Caloric testing with ice water in the unoperated ear elicited nystagmus with a mean value of maximum slow-phase velocity of 129 degrees/s preoperatively and 195 degrees/s 3 mo postoperatively. There was no caloric response on the lesioned side. From the increase in caloric responses from the intact ear we infer considerable restoration of spontaneous activity of vestibular neurons on the deafferented side. 5. The time constant of the VOR was a function of stimulus speed preoperatively with a maximum mean value of 35 s for a 60 degrees/s stimulus. After labyrinthectomy the VOR time constant was low (6.0-9.1 s) at all speeds. Subsequently, in three animals only, there was a small increase (2-3 s) in VOR time constant during the 3-mo period following labyrinthectomy. These results indicate that labyrinthectomy profoundly and persistently impairs the action of the vestibular velocity-storage mechanism.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗
PubMed1981

Surgery for vertigo (you don't have to live with it).

Surgery for vertigo is recommended where there is objective evidence of a unilateral inner ear disorder, when medical therapy fails, and when the patient demands definitive therapy. Common surgical procedures are the endolymphatic subarachnoid shunt, retrolabyrinthine vestibular neurectomy, cochleovestibular neurectomy, and the post ampullary nerve section (singular neurectomy). Vertiginous disorders which can be surgically cured are Ménière's disease, vestibular neuronitis, chronic labyrinthitis, and benign positional vertigo. Due to the recent advances in microsurgery and the development of new surgical procedures in the past 20 years, it is possible to help the vertiginous patient who has been told he must live forever with his problem.

Cochlear Nerve↗
PubMed1977

Brain stem afferents to the fastigial nucleus in the cat demonstrated by transport of horseradish peroxidase.

Although retrograde and anterograde degeneration studies have provided important information concerning brain stem afferents to the fastigal nucleus (FN), these data may be incomplete and should be confirmed by axonal transport methods. Attempts were made to inject horseradish peroxidase (HRP) unilaterally into the FN in a series of adult cats. Animals were perfused with dextran and a fixative solution of paraformaldehyde and glutaraldehyde in 0.1 M phospate buffer. Representative sections were treated by the Graham and Karnovsky ('66) method. Selective HRP injections in one FN resulted in retrograde transport of the marker to Purkinje cells of the ipsilateral vermis and distinctive appendages of the contralateral medial accessory olivary (MAO) nucleus (nucleus beta and the dorso-medial cell column). Retrograde transport of the label was found bilaterally in cells of the medial (MVN) and inferior (IVN) vestibular nuclei, in cell group x and in the nucleus prepositus (PP). Labeled vestibular neurons, most numerous in MVN, were identified in dorsal, caudal and lateral regions, with a slight ipsilateral preponderance. Only a few neurons in caudal, dorsal and lateral regions of the IVN were labeled and none of these included cells of group f. Labeled cells in the caudal third of PP were greatest ipsilaterally. Rostral and caudal injections of FN labeled smaller numbers of cells in MVN, IVN, cell group x and PP. HRP injections of FN and portions of lobules VIII and IX resulted in bilateral retrograde labeling of larger numbers of cells in MVN, IVN and cell group x, and ipsilateral labeling of cells in group y and the interstitial nucleus of the vestibular nerve. Injections of HRP into basal folia of lobules V and VI resulted in retrograde transport of the marker to cells of the medial and dorsal accessory olivary nuclei contralaterally, and to cells of the ipsilateral accessory cuneate nucleus. Transport of label injected into portions of the pyramis was detected in parts of the contralateral MAO and bilaterally in parts of the pontine and reticulotegmental nuclei. This study suggests that the principal afferents of the fastigial nucleus arise from: (1) Purkinje cells of the ipsilateral vermis, (2) restricted portions of the contralateral MAO (nucleus beta and dorsomedial cell column), (3) portions of the MVN and IVN (bilaterally) and (4) caudal parts of the PP. Secondary vestibular inputs to the fastigial nucleus probably are relayed mainly by Purkinje cells in the cerebellar cortex.

Afferent Pathways↗
PubMed1994

[Specifics of innervation of the cranio-cervical transition].

Innervation at the craniocervical transition differs from other regions of the body in certain respects. In particular, thick-calibre neck muscle afferents project directly to the external cuneate nucleus and to the vestibular nuclear complex. This projection is most prominent in segments C2 and 3 and is sparse or absent in more caudal segments. Thus, proprioceptive neck muscle afferents gain direct access to vestibulospinal, vestibulooculomotor and other secondary or even higher-order vestibular neurons. There is extensive convergence of proprioceptive neck and labyrinthine afferents on these neurons, which plays an important role in the control of balance, posture and movements. It can be assumed that dysfunction of this cervicovestibular network results in a variety of clinical problems, in particular, so-called cervical balance disorders.

Afferent Pathways↗
PubMed1998

A role for BDNF in early postnatal rat vestibular epithelia maturation: implication of supporting cells.

The early development of the inner ear is largely determined by two members of the neurotrophic family: brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3). Little information is available on the role of these neurotrophins during the late stages of vestibular development in the rat which take place during the first postnatal weeks. At this period where terminal synaptogenesis and maturation occur, we have investigated the expression and the activity of BDNF, the most important neurotrophin in the vestibular system. Using different experimental approaches, we show that BDNF is released by vestibular epithelia on postnatal day 3 (P3) and continues to have a trophic effect on vestibular neurones in vitro. Immunocytochemistry coupled to confocal microscopy revealed a remarkable evolution in BDNF localization during later stages of development. Whereas BDNF is present in both supporting cells and hair cells at P3, its distribution gradually changed and is highly compartmentalized within the upper part of supporting cells at P8 and P15. In parallel, we observed the presence of a truncated form of the BDNF receptor in sensory hair cells. These results suggest an original role for supporting cells, which could be involved in the release of BDNF during the late stages of synaptogenesis in mammalian vestibular epithelia. In particular, BDNF could participate to the set up of the calyx, a specific nerve structure surrounding type I vestibular hair cells.

Animals↗
PubMed1983

Otoneurological test results analyzed by means of a quantitative statistical method.

This report is a presentation of an approach to the prediction of cerebellar-pontine (C-P) angle tumors and four peripheral vestibular diseases from a mathematical statistical point of view. The present study was performed in an attempt to quantify multidimensional, quantitative data. The data analyzed were from a total of 143 patients with C-P angle tumors, Menière's disease, sudden deafness, vestibular neuronitis, and benign paroxysmal positional vertigo (BPPV). Tests were carried out mainly on otoneurological parameters. By means of discriminant analysis as employed in the quantification method, the patients were classified in the 4-dimensional space.

Adult↗
PubMed1994

Dizziness in aging: a retrospective study of 1194 cases.

In the Royal Victoria Hospital dizziness clinic, 1194 of 9767 (12.22%) patients were 70 years of age or older on the day of the first visit. There were 750 women and 444 men, with no difference in age distribution (p > 0.9). In 367 (27.04%) cases (percentages given as "cases" refer to the number of diagnoses [N = 1357], not the number of patients [N = 1194]), the symptoms were nonspecific, and the diagnosis was uncertain. In 530 (39.13%) patients, paroxysmal positional vertigo was either confirmed or strongly suspected. In the 241 of 254 (94.88%) confirmed cases, the observed paroxysmal nystagmus was compatible with excitation of the posterior semicircular canal. In 119 (8.77%) patients, the dizziness could not be attributed to neurologic or vestibular disease. Meniere's disease, vestibular neuronitis, vascular episodes, and tumors were next in prevalence. The following conclusions were reached: (1) although no difference was found in age distribution between women and men, dizziness was more prevalent among women, which may be because of the higher survival rate of women; (2) the prevalence of paroxysmal positional vertigo was high, with apparent involvement of the posterior semicircular canal in most cases (it is strongly suspected that paroxysmal positional vertigo is frequently misdiagnosed as vascular disease in advanced age); and (3) multisensory deficits, drugs, or systemic diseases, common in the elderly, may cause dizziness. Syndromes affecting the vestibular function, however, may be more prevalent in advanced age than is generally estimated.

Aged↗
PubMed1976

Effects of droperidol in management of vestibular disorders.

The chemo-therapy of vestibular disease has involved a wide spectrum of pharmacological agents insofar as their mode of action is concerned. In our experience, however, droperidol is one pharmaceutical agent which is remarkably effective in depressing vestibular disturbance regardless of etiology. This medication (also called Inapsine) belongs to a relatively new class of compounds known as butyrophenones and its pharmacological action can best be described as a dopa blocking agent. The activity of droperidol on the nervous system first became evident when it was used in combination with the potent analgesic fentanyl citrate in order to produce an anesthetic condition that has been termed neuroleptanalgesia. This mixture (also called Innovar) is rapid in action and results in complete suppression of vestibular activity of both normal subjects and those with Ménière's disease as described by Dowdy, et al., in a preliminary report. These impressive results have prompted us to evaluate the effectiveness of this medication in the treatment of different disorders of the labyrinth. The patients chosen for evaluation were referred for vestibular examination at the Toronto General and St. Michael's Hospitals. Electronystagmography was used to record objectively the effects of the drugs being tested while subjective symptoms including side effects were also noted. These studies involved 20 patients receiving Innovar while 12 patients were tested with Inapsine. Innovar administered in a single dose (droperidol 5 mg, fentanyl 0.1 mg) to patients undergoing acute episodes of vestibular disease (vestibular neuronitis and Ménière's disease) was found effective in the following symptoms and/or signs: nausea, vertigo, nystagmus, the positive past-pointing test and the Romberg test. Innovar appeared to be effective in the amelioration of vomiting although the population was too small to demonstrate statistical significance in this regard. The drug mixture appeared to have no effect on improving auditory acuity and had no significant effects on tinnitus. Adverse reactions to the drug combination were unusual, and, occurring in three patients, were mild as manifested by drowsiness. Since the above findings confirmed the marked effectiveness of the fentanyl-droperidol mixture in the management of vestibular disease, it was decided to determine the relative effectiveness of the droperidol component alone and this was determined by comparing the effectiveness of the drug with placebo in a double-blind study. Review of our findings involving this double-blind study indicates significant responses to Inapsine. This therapy clearly provided the statistically significant response (p less than 0.1, Fisher's Exact Test). This was particularly apparent at the 60-minute evaluation point. While some of the patients receiving Inapsine had recovered earlier, by 60 minutes none of the placebo patients but all of the Inapsine patients had recovered from the vestibular symptoms of Ménière's disease...

Acute Disease↗
PubMed1983

[Microsurgical neurolysis of the 8th cranial nerve in cochleo-vestibular disorders using an extended transtemporal approach].

A series of 17 patients suffering from progressive cochleovestibular disturbances (8), severe attacks of Menière's disease (5), progressive or sudden sensori-neural deafness (2), vestibular neuronitis (1) or unbearable tinnitus (1) is reported. The eighth cranial nerve was exposed from its root at the brainstem to its exit into the fundus of the internal auditory canal (CAI), by an extended middle fossa approach. The surgical technique and the intraoperative observations are described. All cases showed morphological abnormalities such as neuro-vascular compression of the nerve by arterial or venous vessels, either at the brainstem or laterally at the CAI. Horizontal or vertical dislocations of the nerve were also noticed. Traction, compression or even strangulation of the nerve fibres or of their accompanying vessels may be co-factors of the functional disturbances. Striking improvement of the vestibular disorders was recorded following neurolysis of the eighth nerve, showing that retrolabyrinthine abnormalities may be possible causes of Menière's disease and other supposedly labyrinthine disorders. The preliminary results regarding hearing and tinnitus were hitherto unsatisfactory. This fact may be explained by the, as yet, imperfect technique of neurolysis.

Humans↗
PubMedDate not supplied

Analysis of gait in patients with peripheral vestibular disorders.

Analysis of gait in patients with acute unilateral peripheral vestibular disorders was performed using foot switches and electromyography, with the aid of a telemetry system. Among the eight parameters set for the analysis, the occurrence rate of abnormality in the coefficient of variation (CV) was the highest (78%) for the time from heel strike to forefoot strike, followed by that of the location of maximum monophasic contraction of the gastrocnemius during stance, swing and stance. No significant laterality concerning the abnormally increased CV value in those parameters was found except for swing of the foot contralateral to the lesion side. The CV value of each parameter was significantly increased by removing visual cues, suggesting the importance of visual input for steady locomotion. No significant change in CV values of double support was obtained during the acute stage of vestibular neuronitis, indicating that weight transfer from one leg to the other could be smooth even though some difficulty was expected. Abnormal parameters at an acute stage returned to normal limits at recovery stage. The physiological background of the obtained results is discussed.

Acute Disease↗
PubMed1989

[Borderline cases of sudden deafness and so-called vestibular dysfunction].

Forty-seven patients (31 male, 16 female) have been treated at the ENT University Clinic of Marburg during the last 13 years for sudden sensorineural hearing loss combined with disorders of equilibrium. The epidemiological data, history, audiological and electronystagmographic findings of those patients with cochleovestibular lesions are reported. The results of follow-up examination are compared with those of the patients who suffered from sudden deafness and vestibular neuronitis. In patients with combined lesions, special attention was paid to any correlation between the hearing loss and the dysequilibrium, on the one hand, and the restitution of both functions, on the other. We discuss how these patients with cochleovestibular lesions may be distinguished from those with Menière's disease.

Audiometry, Pure-Tone↗
PubMed1999

Significance of head-shaking nystagmus in the evaluation of the dizzy patient.

In a series of studies, the phenomenon of head-shaking nystagmus (HSN) was assessed in 50 control subjects and 1364 consecutive dizzy patients who underwent formal electronystagmography (ENG) at the Toronto Hospital Center for Advanced Hearing and Balance Testing. HSN was compared in a series of 30 patients who underwent conventional electro-oculography (EOG) vs magnetic (scleral) coil eye movement recordings. Clinical correlation of HSN to other parameters of the ENG test battery was performed in another sub-series of 300 patients with known diagnoses. HSN was identified in 31.7% of dizzy patients vs 24% of control subjects. No significant difference in its manifestation was noted between active vs passive head-shaking tests or on EOG vs magnetic (scleral) coil eye movement recordings. When compared to other aspects of the ENG test battery, HSN was neither specific nor sensitive for vestibular dysfunction. It nevertheless correlated well with the presence of a caloric reduction and with increasing R/L excitability differences on ENG testing. When present, HSN was characteristically monophasic in 76.8%, biphasic in 22.7% and triphasic in 0.5% of subjects. The initial direction of HSN generally obeyed Ewald's second law, but the reverse was noted in 27% with monophasic and 17.6% of patients with biphasic HSN. In the subseries of 300 patients with known diagnoses, the presence of HSN was statistically significant (p < 0.05) in patients with peripheral vestibular dysfunction vs psychogenic dizziness. Its presence was also significant in well-documented peripheral vestibular disorders such as Meniere's disease (p < 0.01), vestibular neuronitis (p < 0.05) and acoustic neuroma (p < 0.05). Localization of the disease involvement based on the initial direction of HSN was especially unpredictable in patients with Meniere's disease. The significance and usefulness of the head-shake test in the otoneurological evaluation of the dizzy patient is further commented on.

Dizziness↗