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Congenital and probable developmental vestibular disease is reported in a litter of English cocker spaniel puppies. The syndrome was marked by loss of balance and ataxia initially, but subsequent compensation has left only one individual with "permanent" head tilt.
The signs observed in 6 cases of peripheral vestibular disease included incoordination, head tilt and nystagmus. The intensity of the signs varied greatly with duration of the disease, and in 3 cases facial paralysis was also present. Tympanosclerosis was demonstrable in all cases subject to radiology. Trauma was the causative factor in most cases. The causes of, and relationships between, vestibular dysfunction and concomitant facial paralysis are discussed. The exact etiology of the tympanosclerosis is unknown.
The aim of a documentation in electronystagmography, that is to record as complete and definite as possible the information of a nystagmus relative to all its distinctive marks, hitherto has been reached just as little as the attempt, to develop a fine-quantitative investigatory method suitable for standardization for medical practice. The sources of error caused by the equipment and of physiological nature within a recorded nystagmus trace are exposed and illustrated by respective examples. Outgoing from the theory of the rotatory nystagmus based on the rotation test of the human vestibular system the fundamentels are developed for a complete evaluation method of an electronystagmogram including the elimination of artefacts by the authors' own research work in this field. However the pointed out problems of the electronystagmography are not yet answered in the clinical diagnostic of vestibular diseases, the systematic examination of spontaneous nystagmus and provoked nystagmus still represents the most important, most profitable and well-grounded part of the vestibular investigation in the medical practice.
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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.
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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...
The vestibular aquaeduct was evaluated blindly in tomograms from patients with Meniere's disease or chronic otitis and from patients without ear disorders. The descending part of the aquaeduct was clearly visible in 95% of the patients without ear disease. In the two other groups, it was visible only in about 50%. It is suggested that a narrow or invisible vestibular aquaeduct is an unspecific radiological sign in a variety of ear diseases.
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Secondary nystagmus is frequently seen following cessation of prolonged unidirectional vestibular stimulation. It is explained on the basis of an adaptation during the application of the stimulus which leads to an apparent stimulus in the opposite direction when the stimulus is removed. The same phenomenon would be expected with vestibular disease when after a period of adaptation to the vestibular asymmetry, the affected ear recovers some or all of its function. The seondary nystagmus in this instance beats toward the affected ear and has been termed recovery nystagmus because it is generated by recovery of function. Two cases with recovery nystagmus following acute attacks of vertigo are presented.
Benign paroxysmal vertigo (BPV) is a clinical syndrome of vestibular origin although generally no evidence of vestibular dysfunction can be demonstrated with conventional tests. In a review of 1350 consecutive dizzy patients, there were 125 with BPV and of these, 33 underwent a quantitative rotational test of vestibular function. The rotational results showed reduces vestibular system gain for these BPV patients. In addition, they could be subdivided on the basis of a normal or shorter cupular time constant (Tc). Separation of patients into diagnostic categories revealed that those categorized as cupulolithiasis and viral labyrinthitis had a normal Tc range and those categorized as trauma and idiopathic had a short Tc. The reduced gain and short Tc in the latter group suggest hair cell and/or nerve damage since these same changes occur in patients with destructive peripheral vestibular disease.
Results of bithermal caloric testing in 83 patients with unilateral peripheral vestibular disease, cerebellopontine angle tumors and vertebrobasilar insufficiency were compared in order to find which response measurements identified the most abnormal responses in each disease category. A laboratory digital computer was used to quantitatively assess each caloric response and a large digital computer was used to statistically compare 110 measurements generated from each caloric test. Of the commonly used response parameters maximum slow component velocity (SVMx) and sum of slow amplitudes (SSA) were most sensitive in each category and duration of response (TDUR) was least sensitive. This order was maintained for the vestibular paresis (VP), directional preponderance (DP) and temperature effect (TE) formulas. The magnitude of DP was significantly correlated with the magnitude of spontaneous vestibular nystagmus and both occurred with approximately the same frequency in peripheral and central disorders. There was no reliable way of separating end-organ from VIII nerve or peripheral from central disorders on the basis of the caloric responses.
The usefulness of rotatory testing (impulsive and sinusoidal) as an indicator of impaired horizontal semicircular canal function was evaluated in 63 patients with unilateral and bilateral decreased caloric responses. The rotatory stimuli were precisely controlled over a large magnitude range and EOG recorded nystagmus responses were quantified using digital analysis techniques. Rotatory testing was consistently abnormal in patients with complete unilateral caloric paralyses but was normal in over one-half of the patients with significant but less than complete unilateral caloric paralyses. The difference in maximum slow component velocity (SVMX) of induced nystagmus after the largest rotatory stimuli was the best indicator of unilateral impaired function. The patients with bilateral decreased caloric responses demonstrated three categories of rotatory response: 1. normal at all magnitudes of stimulation, 2. decreased but present after large magnitude stimuli, and 3. absent responses. It is concluded that although rotatory testing cannot replace caloric testing it can provide useful clinical information particularly in patients suspected of having bilateral vestibular disease.
A patient seeking emergency treatment for a labyrinthine disorder is usually complaining of dizziness. The task at hand in the emergency room is, first, to rule out the truly life threatening emergent disorders, and then by means of a rapid but adequate history and physical examination to aid in the differentiation between central and peripheral etiologies. If the problem is central, and especially if there are signs of a true emergency, there should be no hesitation in sharing the responsibility for the care of this patient with a neurologist or neurosurgeon. If one is convinced that the problem is of a peripheral etiology, one most likely is dealing with Meniere's disease, vestibular neuronitis, benign paroxysmal positional vertigo, or true labyrinthitis. An acoustic tumor must always be considered. Appropriate laboratory and x-ray studies may be initiated and therapy begun. Although the emergency room evaluation can be inclusive and accurate, it is necessarily incomplete. There is no substitute for a more thorough history and physical examination under more relaxed conditions, complete audiometry, electronystagmography, polytomography, myelography, angiography, or whatever additional sophisticated studies are deemed necessary. If performed well, however, the emergency room encounter forms an invaluable foundation upon which further diagnostic and treatment decisions are based.
In a study of vestibular responses to caloric stimulation that controlled opportunity for fixation and state of alertness, we evaluated previous findings of diminished nystagmus in schizophrenia. We failed to replicate earlier reports in these respects: (1) None of the psychotic patient groups, when compared with normal controls, showed lower response intensity, latency, or culmination time of the nystagmic response. (2) The schizophrenic groups did not manifest a prevalence of clinically significant asymmetry. We did, however, observe that chronic deteriorated schizophrenics and recent schizophrenics have significantly greater dysrhythmic responses. This diminished orderliness of nystagmus may explain previous reports of absent or diminished nystagmus in the schizophrenics. The results are not compatible with peripheral vestibular disease in schizophrenia, but they may reflect state-related phenomena consistent with disturbances in alertness, which are not necessarily voluntary or motivational in origin.
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