Vestibular Disturbances Research Articles

Vestibular ototoxicity following intratympanic applications of chlorhexidine gluconate in the cat.

Our previous studies have shown that the disinfectant chlorhexidine gluconate (CH) has an ototoxic effect on the cochlea following its topical application in the middle ear space. The purpose of the present investigation was to demonstrate morphologically if CH also has the potential to injure the vestibular organs in the inner ear and, if so, what structures are most strongly damaged. Nine cats were used for the study. The drug dose of CH and the number of its applications to the middle ear were the same as used in our previous study to produce middle ear injuries. In the 2% CH group of cats pronounced degeneration was found in afferent nerve endings and both types of sensory cells. These nerve terminals showed edematous dilatations and contained degenerated mitochondria. Highly dark-stained degenerated mitochondria were distributed in the sensory cells and the afferent nerve terminals in the 0.05% CH group, but these degenerative changes were much less than in the 2% CH group. No otolithic crystals or synaptic vesicles could be seen in the 2% CH group. The results from this study showed that CH as a disinfectant has an ototoxic effect on the labyrinthine vestibule in which the sensory cell-nerve ending complex is affected as the main target. Even when used in dilute clinical concentrations, vestibular disturbances are a likely complication if the drug solution flows into the middle ear through a perforated eardrum.

Effects of lidocaine infusion in cats after unilateral labyrinthectomy.

In the auditory/vestibular system, intravenous lidocaine hydrochloride administration has been reported to provide transient relief from severe tinnitus, reduce dizziness and emesis accompanying Meniere's disease, and sometimes improve audiometric thresholds in sensorineural hearing loss. In this study, the labyrinth was destroyed unilaterally in a series of cats. Animals constantly fell and demonstrated prominent contralateral nystagmus and a rotary motion of the head. Within four hours of a 4-mg/kg intravenous lidocaine hydrochloride injection, the cats were able to ambulate freely without falling. The nystagmus was reduced, and there was virtual absence of the rotary head motion. In contrast, the controls had persistent signs of vestibular disturbance. These results demonstrate that lidocaine infusion ameliorates the effects of unilateral labyrinthectomy in cats and thus may be a potential antivertiginous agent.

良性発作性頭位げんうん症における患側と眼振方向の関係について

Thirty seven patients of benign paroxysmal positional vertigo (BPPV) secondary to ear disease, whose diseased side was definite, were investigated clinically.The age of the patients ranged from 37 to 77 years.In 21 patents vertigo occurred in the critical position and in 19 of these the position was the same side as the disease. In all those with acute auditory or vestibular disturbance, unilateral canal function disturbance or unilateral sensory hearing disturbance, the critical position was the same as the side of the disease.Thirty one paients had positional nystagmus and in 19 of these the nystagmus was toward the affected side. In all patients with unilateral sensory hearing disturbance the positional nystagmus was toward the side of the disease, but of those with acute auditory or vestibular disturbance or chronic otitis media, only half had nystagmus toward the diseased side.Twenty one patients had positioning nystagmus when they moved from a sitting to a head hanging position and only seven of these had nystagmus toward the side of the disease. All of those with unilateral sensory hearing disturbance had nystagmus toward the non-affected side.

Audiovestibular tests in the diagnosis of cerebellopontine angle tumours.

Symptoms and signs were recorded in a series of 78 patients with a cerebello-pontine-angle (CPA) tumour and in 92 patients with symptoms and signs suggestive of such a lesion but with a negative CT scan. Variable symptomatology was found in the tumour cases. A substantial proportion of the patients had experienced sudden phenomena such as rotatory vertigo and/or sudden hearing loss. A CPA tumour must therefore be considered in almost every case of unilateral auditory or vestibular disturbances. Unfortunately, conventional audiovestibular tests have a low sensitivity of around 50%, with the exception of stapedial reflex threshold elevation (89%). The specificity on the other hand is quite low for this test, whereas other test results, like a genuinely pathological stapedial reflex decay, carry a high specificity of 60%. However, brainstem response audiometry (BRA) exhibited a very high sensitivity (100%) coupled with a reasonable specificity (54%), making it a suitable single test for screening patients suspected of having a CPA tumour. A program for the diagnostic work-up is suggested.

Vestibular disturbances after neck muscle sectioning in rat.

The nystagmus response to rotatory acceleration was investigated in rats. The stimulus was exerted by a turntable accelerated 13.3%/sec2 for 9 seconds and after 1-2 minutes decelerated accordingly. Eye movements were recorded using the search coil technique. The duration of postrotatory nystagmus and speed of slow component velocity gain were recorded. After unilateral neck muscle sectioning no change appeared. After bilateral sectioning the nystagmus response was increased with a remaining high gain and prolonged response duration. The experiments show the influence by the muscles on the velocity storage mechanism.

Two types of head-shaking tests in vestibular examination.

In clinical vestibular examination, there are two types of head-shaking tests, in each of which the patient's head is shaken in a similar way. One is the head-shaking test for the detection of latent spontaneous vestibular nystagmus. In this test, the patient's eyes are observed for nystagmus immediately after a passive rapid head-shaking around a vertical axis, using Frenzel's glasses in a dark room. The nystagmus is induced frequently in patients with peripheral and central vestibular disturbances. In peripheral vestibular disturbances, the induced nystagmus can be classified into deficiency-type nystagmus, recovery-type nystagmus and biphasic nystagmus which is usually a mixture of the two. A second head-shaking test is the head-shaking test for the evaluation of jumbling. In this test binocular visual acuity is measured while the patient shakes his head two or three times per second, ten to twenty degrees horizontally or vertically, and compared with that when his head is still. A diagnosis of jumbling is made when the visual acuity during head-shaking is less than half the visual acuity when the head is motionless.

Body sway analysis by a feedback model and observation of patients with vestibular, central and peripheral equilibrium disturbances

Disturbances of standing posture regulation in patients with vestibular, cerebellar, spinal and peripheral disorders were studies by a time series analysis with a 5-dimension feedback model.Sways of the head, shoulder, hip, knee and foot during upright standing were recorded with a position sensor system and stored in a PDP-11 computer. With the use of a 5-dimension feedback model the stored data were processed by a specially designed program.1) In a patient with bilateral loss of labyrinthine excitability and a forward-backward (F-B) sway in the statokinesigram, the determinant was 0.43 in F-B sway. The power spectrum and the correlograms indicated periodic components of about 0.4 Hz in F-B sway. The impulse responses to head movements converged with periodic sways against external disturbances. The transfer functions calculated with shoulder movement as input and head and knee movements as output indicated increases of the gain. The relative power contribution showed that the pro-portion of head movement increased during sway of the shoulder, hip and knee.2) In a patient with unilateral loss of labyrinthine excitability and a right-left (R-L) sway, the power spectrum and the correlograms indicated periodic components of about 0.3 Hz in R-L sway. The relative power contribution showed that the proportion of shoulder movement increased during the sway of the head, hip and knee in low frequency.3) In a patient with spino-cerebellar degenera tion and a diffuse, large sway, the determinant wa: 0.025 in F-B sway. The power spectrum and the correlograms indicated periodic components of about 0.3 Hz. The impulse responses were divergent The transfer functions indicated disorders of coordination.4) In a patient with an infarction of a cerebellar hemisphere and a small R-L sway, the determinants were from 0.57 to 0.77. The power spectrum and the correlograms indicated poor periodicity. The impulse responses were slightly divergent. The transfer functions and relative power contribution were similar to those in normal subjects.5) In a patient with Caisson disease and a large F-B sway, the determinant was 0.007 in F-B sway. The impulse responses were divergent. The transfer functions calculated with hip movement as input and head and knee movement as output indicated in-creases of the gain.6) In a patient with Friedreich's ataxia and an enlarged sway with the eyes closed, the determinants were from 0.31 to 0.74. The power spectrum and the correlograms indicated no periodicity. The transfer functions were similar to those in normal subjects. The relative power contribution showed that the propotion of the hip movement increased during sway of the head and knee.7) In a patient with Charcot-Marie-Tooth disease and an enlarged sway with the eyes closed, the determinants were from 0.73 to 0.95. The impulse responses were convergent. The transfer functions and the relative power contribution were similar to those in normal subjects.

円周歩行検査による迷路機能不均衡の検出

円周歩行検査による迷路機能不均衡の検出

Retrolabyrinthine Vestibular Nerve Section: Limitations and Clinical Experience

Finding the correct surgical approach for the vertiginous patient continues to be a challenge. At the Western Section Meeting of the Triological Society, Carol A. Bowman, MD, and Charles A. Mangham, Jr, MD, of the Virginia Mason Clinic, Seattle, reviewed their experience with the retrolabyrinthine vestibular nerve section. It was pointed out that even though the control rate for vertigo is reportedly high with this procedure, many patients still have postsurgical vestibular symptoms. Bowman and Mangham reviewed 36 cases and reported control of the rotatory vertigo in 94% of the patients involved. In questioning their patients, they found that the majority continued to have symptoms of vestibular disturbance and balance disturbance even though the rotatory vertigo was controlled. In spite of the limitations of the procedure, the authors still feel that it is efficacious for the vertiginous patient.—James L. Parkin, MD, MS, Salt Lake City

Microsurgical treatment of patients with vestibular and cochlear symptoms

Eighteen patients with vertigo, tinnitus, and various hearing disturbances were treated by posterior fossa exploration and microvascular decompression of the eighth cranial nerve; they were followed for more than 3 years. After successful decompression of the eighth nerve from offending vessels, the attacks of vertigo disappeared in 11 patients, improved markedly in 3 patients, and improved mildly in 4 patients. The tinnitus vanished in three patients and decreased in nine. The hearing disturbance improved in only five patients and worsened in three. Because of the satisfactory improvement of the attacks of vertigo, which are the most distressing symptoms for patients, we recommend surgical exploration for patients with severe symptoms of vestibular disturbances.

Vestibular habituation training and posturography in benign paroxysmal positioning vertigo.

A number of cases with typical positioning vertigo (BPPV) show a unilateral vestibular hypofunction (UVH) by caloric testing. However, treatment by habituation exercises (VHT) improves vertigo independently of the presence of UVH. Moreover, VHT has no influence upon the results of caloric and rotation tests. These findings prove the independence of the pathogenetic mechanisms of the peripheral vestibular disturbances UVH and BPPV.

Clinical Significance of Biphasic Head-Shaking Nystagmus

Biphasic head-shaking nystagmus (b-HSN) is a rather uncommon phenomenon which was first reported by Kamei in 1975 (Arch. Otorhinolaryngol. 209: 59-67, 1975). He pointed out that b-HSN appeared in cases of peripheral vestibular disturbance especially in the cases of unilateral disturbance, and that the direction of the second phase indicated the damaged side. While investigating cases of b-HSN, the author encountered some cases which did not correspond to b-HSN reported by Kamei. Nineteen patients in whom b-HSN was recorded by electronystagmography were investigated. These patients visited our clinic in the last two years and showed no spontaneous nystagmus in the narrow sense. Of these, 16 were cases of unilateral peripheral vestibular disturbance. In 13 of these (81%), as Kamei had described, the first phase beat toward the healthy side and the second phase beat toward the damaged side, while in the remaining 3 cases (19%), the first phase beat toward the damaged side, and the second phase toward the healthy side. This is contrary to Kamei's report. This time the b-HSN was also observed in 3 cases of central vestibular disturbance, which indicates that b-HSN occurs not only in cases of peripheral vestibular disturbance but also in cases of central vestibular disturbance.

The relative selectivity of anticholinergic drugs for the M1 and M2 muscarinic receptor subtypes.

Anticholinergic drugs are used to treat a number of neurologic disorders, including parkinsonism, vestibular disturbances, and dystonia. Traditionally, these drugs have been thought to act in similar fashion, as competitive antagonists at a single class of muscarinic receptors, and not to differ significantly in their therapeutic efficacy. Recently, however, pharmacologic studies have shown that the novel antagonist pirenzepine is capable of recognizing heterogeneity among muscarinic receptors; high-affinity pirenzepine sites have been classified as M1 sites and low-affinity sites as M2. This study examined whether the anticholinergics currently available for treatment of neurologic symptoms have selectivity for these subtypes and whether they differ in their degree of selectivity; the study showed that these drugs do demonstrate selectivity. All had greater affinity for the M1 site, indicated by higher affinity for rat forebrain membranes, where M1 predominates, than hindbrain preparations, where M2 predominates. The degree of selectivity varied greatly; some compounds, such as ethopropazine, had little M1 selectivity, whereas others, such as scopolamine, trihexyphenidyl, and biperiden, were quite selective, like pirenzepine. It is unknown whether these differences in selectivity have any immediate therapeutic implications. However, these results support the emerging concept of muscarinic receptor subtypes and the prospect of developing more selective agents, with enhanced therapeutic efficacy.

鼓室形成術前後のＥＮＧ検査所見

In an attempt to clarify the effect of tympanoplasty on the vestibular systems, electronystagmograms (ENG) were recorded in 201 patients with chronic otitis media before and after tympanoplasty. ENG recordings were performed under four conditions : eyes closed and eyes open in darkness with or without mental calculation.Nystagmus was demonstrated in 61% of patients before tympanoplasty, a much higher incidence than in normal subjects. Both slow phase eye velocity and frequency of nystagmus were analyzed, and no significant difference was found before and 3 weeks or 6 months after tympanoplasty. These data suggest that vestibular disturbances in patients with chronic otitis media are irreversible and remain unstable even after tympanoplasty. On the other hand, it can be said that the surgical procedure which we used had no direct influence on the vestibular labyrinth.

Perspectives on the pharmacotherapy of vertigo.

Recent evidence from experiments in animals suggests a rationale for more effective pharmacologic and physical therapy in patients with vertigo. In particular, one must consider the possible effects of medications on the adaptive processes that naturally mediate recovery from vestibular lesions. The challenge now is for clinicians to devise medication and exercise regimens for patients with vestibular disturbances and critically (and quantitatively) evaluate their effects.

Small fenestra stapedectomy: technique and advantages.

We discuss the rationale and advantages of the small fenestra technique (SFT) of stapedectomy. When results from conventional stapedectomy techniques are compared with those of SFT, the small fenestra technique shows improved hearing in the high frequencies of 2,000, 4,000, and 8,000 Hz, improved speech discrimination, reduced vestibular disturbance, and reduced iatrogenic trauma to the cochlea.

Epidemiological Survey of Vestibular Disorders (Second report)

In 1980, the Vestibular Disorders Research Committee of Japan, which is supported by the Minitsry of Health and Welfare, was founded by 24 doctors, from several districts of Japan. First, the Committee drated the diagnostic criteria for several peripheral vestibular disorders, such as benign paroxysmal vertigo, vestibular neuronitis, bilateral loss of labyrinthine function, inner ear syphilis. In an epidemiological survey, 783, cases of vestibular disorders were collected by the Committee members.This second report describes a comparative survey of the monthly incidence of vertigo, equilibrium disturbance, and vestibular disorders (including pathological types and classification of symptoms) among outpatients visiting the same clinics for the first time in 1982 and 1983.There was no appraciable difference between the two surverys in terms of the total number of outpatients affected by vestibular disturbances, but these were some insignificant variations in some of the factors examined.When we have stabilized the incidense of the various pathological types of diseases by further surveys, we will perform an epidemiological survey which includes the contemporary incidence and compares it with the results of previous surveys.

直立時重心動揺の周波数分析 ＩＩ 末しょう性前庭障害と中枢障害について

Frequency analysis of the movement of the center of gravity during standing erect was investigated in this study. One hundred cases of both the peripheral vestibular disease and the central nervous system disturbance were examined. The following results were obtained.1. Effects of visual righting reflex. In the peripheral vestibular disturbance, increase of waves between 0.5 and 3Hz or 1 and 4Hz in both the X (right and left direction) and the Y (foreward and backward direction) and relative decrease of waves of less than 0.5Hz appeared when the patients were asked to close their eyes. However, in the cases of central disturbances in the Y such a difference between with eyes open and with eyes closed was not observed, though in the X the result was similar as one in the peripheral vestibular disease.2. Comparison between the ataxic patients and normal controls.In the peripheral vestibular disease, increase of waves of less than 1Hz in the X, increase of waves between 0.5 and 1Hz in the Y with eyes open and increase of waves between 1 and 2Hz in the X with eyes closed were statistically confirmed. In the cases of Meniere's disease a result of increase of waves between 0.5 and 1Hz with eyes closed in the X was added. In the cases of central disturbances, the results in the X with eyes open and with eyes closed were same as the results of peripheral vestibular disease. However, lack of increase of waves between 0.5 and 1Hz in the Y with eyes open was observed.Such a characteristic frequency wave form of the movement of the center of gravity in standing posture in the cases of different diseases may have the clinical diagnostic value.

Physiological and psychological correlates of motion sickness.

Motion sickness (MS)has been inconclusively associated with personality and physical vestibular functioning in both males and females. The present work consisted of six tests: test of field dependency; pure balance test; motion sickness questionnaire; body steadiness test; primary suggestibility test; resistance to disturbance test. In addition the EPI was completed by a proportion of subjects. Male and female data for the 15 male and 15 female subjects in an age range 20 to 30 years, obtained from within Bedford College, University of London, were factor analysed separately. The results show that, firstly, field dependence, as understood by Witkin, is not associated with any of the factor and correlated significantly (r = 0.83, P less than 0.001; two-tailed test). The same correlation in women was not significantly (r = 0.17). For females, MS and neuroticism appeared on the same factor and correlated significantly (r = 0.62, P less than 0.05; two tailed test). The same correlation in men was not significant (r = 0.06). This suggests that MS in females is associated primarily with neuroticism, whereas in males it is associated with vestibular disturbance thresholds.

Compensation of vestibular symptoms in hemilabyrinthectomized guinea pigs. Role of the sensorimotor activation

The effect of sensorimotor activation on compensatory rate of vestibular asymmetries after unilateral labyrinthectomy was analyzed in guinea pigs. An intensified sensorimotor activation was obtained by putting in water the animals immediately after the appearance of hemilabyrinthectomy (HL) symptoms. The water-maintained group exhibited a faster dampening of vestibular disturbances in comparison with control animals. Both ocular and postural asymmetries declined to about 50% of peak values after 2–3 h from HL, while in control group the same extent of recovery was achieved in 4–6 h from HL. It is concluded that the generalized activation of the ascending spinal pathways carrying exteroceptive and proprioceptive information to the vestibular nuclei represents a favourable condition for the regainment of ocular and postural balance impaired by HL.