The role of the Endolymphatic Duct and Sac is discussed from morphological and experimental evidence of its importance in inner ear fluid circulation. The morphological characteristics of the sac is discussed from animal studies and also in man. It is concluded that the sac acts as a reabsorbtive site for endolymph and that it can also remove high molecular debris from the endolymphatic compartment. It is also concluded that it exhibits immunological properties of great interest. Also a secretory capacity of proteoglycans can be of importance when discussing inner ear pathology and the Meniere's disease.
Primary and secondary nation-wide surveys were designed to estimate the prevalence of Meniere's disease. In the primary survey, questionnaires were sent to 4, 038 clinics in hospitals with more than 200 beds throughout Japan; 1, 049 otolaryngology, 1, 834 internal medicine, 685 brain surgery, 262 neurology, 138 psychosomatic medicine and 10 geriatric medicine clinics. The questionnaire simply requested the number of patients with Meniere's disease in each clinic. To clarify the epidemiological picture of Meniere's disease, the secondary survey was carried out in the clinics which responded to the primary survey. The secondary survey included the name, sex, birth date and other necessary items. The primary and secondary nation-wide surveys reported a total of 7, 073 cases of Meniere's disease in Japan. The prevalence rate 5.8 per 100, 000, 1.6 times higher in female than in male. It was highest in the 6th decade, followed by the 5th, 4th and 7th.
Long-term hearing changes were investigated in 63 patients with Meniere's disease (46 unilateral, 17 bilateral). In most patients with unilateral Meniere's disease, the hearing level noted on the initial visit remained unchanged for a long time. In young patients who had therapy at an early stage, hearing was improved or conserved at a good level. On the other hand, in most patients with bilateral disease, hearing on the initial visit was worse than in those with unilateral disease, and it became gradually worse. Those with late onset often had very poor hearing and early therapy was not possible. Hearing changes in unilateral and bilateral Meniere's disease appear to have different mechanism.
In 1974, the Meniere's Disease Research Commitee in Japan designated the criteria for the diagnosis of Meniere's disease. However, there was little consideration of the objective neuro-tological findings in this disease. During 1987, 451 patients with vertigo and/or dizziness, who visited the Neurotological Clinic of Toyama Medical & Pharmaceutical University Hospital, were tested neurotologically. There were 27 definte and 30 suspected cases of Meniere's disease diagnosed according to the Committee's criteria. However, seven patients with vertigo and cochlear symptoms, who had subjectiverly satisfied the cirteria, were excluded because of other CNS findings, such as abnormal hyperexcitatory caloric response, abnormal OKN findings and abnormal image findings (CT-scan, VAG). These clinical observations lead us to conclude that the criteria for the diagnosis of Meniere's disease should include objective findings, especially tests for endolymphatic hydrops, such as the glycerol test, electrocochleography (ECoG) and the furosemide VOR-test.
In patients with Meniere's disease, hearing has been thought to fluctuate, especially in the early stage. However, in some cases, hearing deteriorates suddenly and does not recover even in early stage. In other cases, hearing deteriorates gradally to some degree. We have attempted to establish prognostic criteria for hearing impairment. Pure-tone audiometry, the glycerol test, and electrocochleography performed in 136 patients with definite Meniere's disease were analyzed retrospectively. 1) Among 73 patients with an interval of less than 3 years between the first attack of vertigo and the first audiometry, the average hearing threshold was less than 30 dB in 28 patients (38%), and 60 dB or more in 14 patients (19%). On the other hand, among 37 patients with an interval of 3 or more years 6 (16%) had had hearing thresholds less than 30 dB and 16 (43%) had average hearing thresholds of 60 dB or more. Thus patients with a longer duration of Meniere's disease generally have more severe hearing loss. We also observed that in some patients hearing deteriorated rapidly even in the early stage as Stahle reported (1976). 2) In 29 patients, we could repeat pure-tone audio-metry one year after the first audiometry. Of the 19 patients with a history of less than 3 years, one patient had poorer hearing, 3 showed improvement, and in 15 there was no change in the average hearing threshold. Of the 10 patients with more than 3 years of symptoms none had improved hearing, 3 had worse hearing and in 7 there was no change. 3) Of the 9 patients with a positive glycerol test with a history of less than one year, one patient had deterioration, 3 improvement, one fluctuation and 4 no change in the average hearing threshold. How-ever, in 5 patients with a negative glycerol test, 4 had worsening and one no change, no improvement and fluctuation in hearing. These clinical observations suggest that the glycerol test may provide some vital information for predicting the prognosis in hearing impairment in Meniere's disease.
We investigated severe cases of Meniere's disease. The diagnosis was based on the criteria of diagnosis of severe cases of Meniere's disease by Watanabe (1978), Severe cases existed in 11 (7 males and 4 females) of 41 patients with Meniere's disease. In 10 of these cases, attacks of vertigo occured above once a month on an average for more than 3 months. In addition, their hearing level was more than 40 dB and they had 20% canal paresis. However, there was no significant difference in the results of electro-cochleography and glycerol test between patients with and without severe cases.
A prototype of a tension testing machine capable of measuring microloads (“the microtension tester”) was developed to examine the mechanical properties of fine bio-membranes. The mechanical properties of the human membranous labyrinth were studied in two temporal bones from one human being. The test was carried out at room temperature in physiolocical salt solution. The tension rate was 1mm/min. The measurement was done on formalin fixed specimens, but on the basis of our findings reported recently on the mechanical properties of the semicircular canals of fish, frogs and guinea pigs, the results were converted into figures representing those of fresh tissue. In comparisons of tensile strength, saccular membrane was the weakest, followed by Reissner's membrane and utricular membrane, and semicircular canal membrane was the strongest. There was a good correlation between the thickness and the strength of the membrane. These findings suggest that the increase in endolymph volume or pressure takes place throughout the entire labyrinth in Meniere's disease, and because of the differences in the mechanical properties of the membranous labyrinth, endolymphatic hydrops occurs only in the cochlea and the saccule.
Temporal bones of 17 aged cadavers were examined. In 12 cases there was a history of “vertigo”. Distension of Reissner's membrane was present in 17 out of 20 cochleae of those with “vertigo” and in 5 out of 9 cochleae of the controls. Pigmentation granules were observed in the stria vascularis and the epithelium of the saccules. Ultrastructurally, these pigmented granules were aggregates of round electron-dense granules located in the cytoplasm, and they were not decolorized by treatment with H2O2, suggesting that they were not melanin. The medulla oblongata of 6 SHR rats suffering from a kind of “vertigo” was also examined. In one rat, degenerating neurons which stain deeply with Luxol-Fast blue were observed in the reticular formation of medulla oblongata. Further study is needed to evaluate this pathological finding.
To examine drug penetration into vestibular organ, the distribution of kanamycin-sulfate (KM) in the peripheral organ was examined immuno-histologically. Intravenously administered KM easily reaches to the sensory epithelial layer of the crista ampullaris and macula statica in 3090min, although it has been said that the blood-laryrinth-barrier inhibits the penetration of drugs. The distribution of KM is similar to the pattern of degeneration of the vestibular organ induced by aminoglycosides. After 2448hr, KM is still present in the vestibular organ, not in the sensory epithelium but in the sub-epithelial tissue.
Complement is known to be related to many inflammatory reactions, and C4a, C3a and C5a, known as anaphylatoxins, cause strong inflammatory reaction although they are unrelated to anaphylaxis caused by immunoglobulin E. We made anaphylatoxins from guinea pig serum plus zymosan. Anaphylatoxins were inoculated into the carotid artery. We have already reported that the stria vascularis (S.V.) in the various cochlear turns, except the cochlear basal turns, was extremely atrophied after 72 hours. In this study, anaphylatoxins were inoculated into the carotid artery and after 7, 10 and 15 days, the S.V. was examined. It was extremely atrophied, similar to its appearance after 3 days. After 7 days, atrophy was observed in the third turn in 5 out of 12 S.V. (42%), in the fourth turn in 12 out of 12 S.V. (100%) and in the apical turn in 3 out of 3 S.V. (100%). After 10 days, atrophy was observed in the third turn in 2 out of 12 S.V. (17%), in the fourth turn in 9 out of 12 S.V. (75%) and in the apical turn in 3 out of 3 S.V. (100%). After 15 days, atrophy was observed in the third turn in 2 out of 12 S.V. (17%), in the fourth turn in 6 out of 12 S.V. (50%), and in the apical turn in 2 out of S.V. (67%). Thus atrophy in the S.V. due to anaphylatoxin improved with time.
The localization of trimetaphosphatase (TMPase) activity in the epithelium of the guinea pig cochlear duct was investigated cytochemically and compared with that of acid phosphatase (ACPase) activity and that of horseradish peroxidase (HRP) injected into the subarachnoid space. Cochlear from Hartley strain guinea pigs weighing 250300g, were fixed with 2% glutaraldehyde and decalcified with 10% EDTA. TMPase activity was detected by the methods of Doty et al. (J Histochem Cytochem 25 : 1381, 1977) and Kobayashi et al. (J Histochem Cytochem 36 : 959, 1988), and ACPase activity by the method of Robinson and Karnovsky (J Histochem Cytochem 31 : 1197, 1983). ACPase activity was observed in a small number of round lysosomes in the epithelial cells, and in short tubular lysosomes in the marginal cells of the stria vascularis and root cells. However, many round and tubular lysosomes showing TMPase activity were seen in the marginal cells of the stria vascularis, root cells and interdental cells. The re-action products of TMPase activity were electron-dense fine granules on the limiting membranes and in the lumens of the lysosomes. The localizing-pattern of TMPase activity in epithelium was very similar to that of HRP injected in the subarachnoid space. The lysosomal fraction was collected from guinea pig and rat kidney cortex, and TMPase was separated from ACPase by electrophoresis with 5% polyacrylamide gel and stained with 0.5% yellow ammonium sulfide after incubation in a cytochemical medium for enzyme localization. The present results show that TMPase is different from ACPase in its biochemical properties and its cytochemical localization in the lysosomal system. TMPase-positive lysosomes in the epithelium of guinea pig cochlear ducts seem to possess a function associated with pinocytosis, and might also be involved in the formation of endolymphatic hydrops.
At the end of this series of reports, further information has substantiated the existence of immunoglobuline (IgG, IgA, IgM) in the lateral wall of endolymphatic sacs, obtained during endolymphatic sac surgery in 20 patients with Meniere's disease and one pair of sacs from a cadavers. As an immunohistochemical procedure, the PAP method (peroxidase-anti-peroxidase method) was utilized and IgG was recognized in the epithelium and the subepithelial layer of the sacs of 13 of 20 (65%) patients with Meniere's disease, while IgA and IgM were absent in all of the patients. On the other hand, there were no immunoglobulin deposits in the same part of the sac of the cadaver. Summing up the findings of this series, it can be concluded that there are IgG deposits in the epithelium and the subepithelial layer of the endolymphatic sacs of patients with Meniere's disease, and it is probable that some immunological disorders exist in the endolymphatic space, including the sac, and that they might be closely relataed to one of the causes of endolymphatic hydrops.
Limax flavus agglutinin (LFA) and wheat germ agglutinin (WGA) were employed to determine the localization of N-acetylneuraminic acid (NANA=sialic acid) and N-acetylglucosamine (Glc-NAc) on thin sections of Lowicryl K4M embedded guinea pig striae vasculares, and the two lectins were revealed by means of fetuin-colloidal gold and ovomucoid-colloidal gold complexes, respectively. LFA labeling was found in many of the cytoplasmic vesicles located in the supranuclear region of the marginal cells, as well as in the basement membrane of the perivascular spaces. Intercellular spaces between marginal and intermediate cells, and those between marginal and basal cells were also positive. The plasma membrance, however, was completely unlabeled in all types of cells. WGA binding sites, on the other hand, were detected along the plasma membrane of all cells constituting the stria vascularis and in some of the supranuclear cytoplasmic vesicles in the marginal cells. Sugar inhibition experiments confirmed the specificity of LFA and WGA for NANA and Glc-NAc, respectively. The present results, together with the data previously obtained indicate that some of the cytoplasmic vesicles in the supranuclear region of the marginal cells play a role in the internalization mechanism and suggest their involvement in the selective uptake of ions.
The effects of adenosine 2'-diphosphate (ADP), which causes regional ischemia due to platelet micro-emboli, the inner ear oxygen tension (PO2) was studied in the guinea pigs. Two PO2-sensitive microelectrodes were inserted through a small hole into the endolymph of the cochlea and canal. The endolymph PO2 was simultaneously measured by a polarographic technique. The PO2 in the cochlea and canal during normal conditions was 60.3 (±12.2) and 61.3 (±14.7), respectively. When a small dose of ADP (0.1mg/kg) was injected into the carotid artery, endolymph PO2 decreased transiently. The decrease of cochlea PO2 tended to be larger than that of canal PO2. This finding indicats the higher vulnerability to emboli of the peripheral auditory organ.
The pressure difference between perilymph and endolymph in guinea pigs with endolymphatic hydrops was investigated one month after surgical obstruction of the endolymphatic sac and duct. Pressures were measured with a servo-nulling system (WPI micropressure system model 900). A glass micropipette was inserted into the perilymphatic space through the round window membrane to measure the perilymphatic pressure, then the micropipette was inserted more deeply through the basilar membrane to measure the endolymphatic pressure. There was no significant pressure difference between the perilymph and the endolymph in guinea pigs with endolymphatic hydrops. Reissner's membrane may be distended very easily when the endolymphatic volume is increased, and it is not stiff enough to maintain the pressure difference between the perilymph and the endolymph.
The effects of glycerol and mannitol on oxygen tension of the cochlear perilymph were studied with a polarographic technique in the guinea pig. Following a transient fall immediately after the intravenous administration of each drug, the oxygen tension increased to reach a peak 5 to 10minutes later, and then decreased gradually. The magnitude and duration of the oxygen tension increase were larger after the administration of glycerol than after that of mannitol. These results were in good agreement with the clinical experience that glycerol is more effective than mannitol in increasing hearing in Meniere's disease. The increase of oxygen tension in the cochlea, therefore, is considered to be one of the possible contributory factors in the improvement of hearing in patients with Meniere's disease after glycerol administration.
The elasticity of Reissner's membrane was investigated in guinea pigs with experimentally induced endolymphatic hydrops. Isosorbide, an osmotic diuretic, was administered to reduce the size of the endolymphatic space and thereby decrease pressure on the bulging Reissner's membrane. If elasticity is present, a consequent shortening of this membrane would be expected. Significant folding in the basal turn of the cochlea was observed, but careful measurement with a microscope, video camera, and computer arrangement revealed no contraction of Reissner's membrane in comparison with guinea pigs which had not received isosorbide. This indicates a lack of elasticity in the membrane following the occurrence of endolymphatic hydrops, suggesting irreversibility of the elongation process.
The effect of glycerol on the cochlear blood flow (CBF) and perilymphatic pressure (PP) was studied in guinea pigs. CBF and PP were measured simultaneously with a laser-doppler flowmeter and a servo-nulling system, respectively. Administration of 12 ml/kg of 50% glycerol or of physiological saline was carried out through a polyethylene feeding tube. Glycerol administration caused a marked increase of CBF and decrease of PP, while physiological saline produced no change. However, some time lag was noted between the changes of CBF and PP. That is, the change of CBF preceded that of PP, and CBF had returned to its normal value when PP reached its maximum Therefore, the increase of CBF seems to be unrelated to an increase in serum glycerol or a decrease of inner ear pressure.
To study the effects of hyperosmolar solutions, such as glycerol, mannitol, and urea, hydrogen (H2) clearance in the endolymphatic and perilymphatic systems was measured simultaneously with a bichannel hydrogen clearance monitor, The methods of this experiment were described in an early report as Chapter 1. H2 clearance was measured for 10 minutes before and for 10 minutes after the infusion of glycerol, mannitol, or urea. The half life times in the endolymph and perilymph decreased significantly after the infusion of glycerol. This shortening of half time was more marked in the perilymph than in the endolymph. Therefore, the difference in half life time between the endolymph and perilymph disappeared later. The half life time in the perilymph decreased significantly after the infusion of urea, but the half life time in the endolymph was not significantly different before and after the infusion of urea. The half life times before and after the infusion of mannitol were not significantly different in either the endolymph or the perilymph. A personal computer (NEC PC-9801) and soft ware made by ourselves were used to analyze these data. These results correspond closely to those observed when such hyperosmolar solutions are administred as treatment for Meniere's disease.
We induced experimental hydrops in guinea pigs after cauterizing the sac with silver nitrate and observed their inner ear vessels by scanning electron microscope using the casting method. Abnormal morphological changes were seen in the microvascular system of the cochlear lateral wall and the saccular macula on hydrops side, suggesting a circulatory disturbance in the inner ear.
This experiment employed the blood vessel casting method and stylene cracking method to study morphologically blood flow regulation in the vestibule. (I) The results indicate that (1) the arteries have a blood p. mping function, (2) coiled arterioles are involved in blood pressure regulation, (3) the veins function to increase blood pooling. (II) In the utricular macula, an arterio-venous (A-V) anastomosis is present below the capillary plexus. This A-V anastomosis appears to be very important in the regulation of local blood flow.
1. We evaluated the effects of ATP (adenosine triphosphate), dilazep dihydrochloride and vinpocetine by testing vertebral arterial blood flow with the ultrasonic doppler method. Each drug was administrered orally to patients with vertigo or dizziness for 4 to 8 weeks. 2. The rate of clinical efficacy of ATP was 88.9%, that of dilazep dihydrochloride was 87.5%, and that of vinpocetine was 73.7%. No adverse reaction was observed. 3. In the patients who received vinpocentine, there was a significant increase of vertebral arterial blood flow and a significant decrease of the right left difference in that flow. 4. In 10 patients whose vertebral arterial blood flow before administration was normal, the clinical efficacy rate was high, 100% and 78.3% in the decreased blood flow group, and 78.3% in the right-left difference blood flow group. 5. In the patients with abnormal vertebral arterial blood flow before treatment and after with normal flow, after treatment, the rate of efficacy was higher than in the patients with abnormal flow after treatment. 6. Administering ATP and dilazep dihydrochloride together had a good clinical effect and improved vertebral arterial blood flow.
Typing of Class I antigen of HLA-A, Aw, B, Bw, Cw and Class II antigen of HLA-DR, DRw, DQw was done in 44 Japanese patients with Meniere's disease (21 bilateral and 23 unilateral). None of them had a family history of Meniere's disease. HLA-Bw 52 antigen was found in 23% and HLA-DRw8 in 8% of the patients. The frequency of the former was higher and that of the latter was lower than in healthy control (N=120); however, the difference was not significant after corrections were done for the number of antigens tested. There was no significant difference in the frequency of the antigen in those with bilateral or unilateral involvement.
A clinical study of the patients with peripheral vestibular disorders and 25 normal subjects was conducted with the visual somatosensory body equilibrium test (EquiTest® system). This test system analyzes patients' responses to stimuli to various components of the body balance system. The two series of test conditions were calculated as follow. (1) Sensory organization test : The contributions of the three sensory inputs providing orientation information were evaluated : visual, vestibular, and somatosensory. The patients were forced to stand without visual or somatosensory information or with false stimuli. (2) Movement corrdination test : The patient's ability to make corrective movements to regain equilibrium was tested. The patients were exposed to brief backward and forward horizontal movements of the support surface, which was also tilted so the tose were up or down. (1) The balance system and righting reflex in patients with peripheral vestibular lesions and in normal subjects were evaluated with the EquiTest®. (2) Correct visual or somatosensory information was indispensable for patients with peripheral vestibular disorders to maintain stable standing. Somatosensory information was vitally important. (3) The activity of the stretch reflexes in the lower limbs of the patients was not much affected when the eyes were open.
Thirty three patients with sudden deafness were examined by pure-tone audiometry and the trapezoid rotation test (±2, 4, 6, 8 and 10°/sec2, 10″) using Contraves' computerized rotary chair system, at least 3 times in their clinical course. Of these patients, 17 (52%) complained of vertigo, and labyrinthine preponderance was noted in 28 cases (85%) in the trapezoid rotation test. Twenty patients (61%) showed a predominance on the impaired labyrinthine side (labyrinthine preponderance, ipsilateral; LPi) transiently during recovery from low tone hearing loss. Therefore, the transient LPi was thought to be a sort of recovery nystagmus.
Harmonic acceleration tests in the yaw plane with the head centered or in an eccentric position 90cm from the axis of rotation were performed in 41 patients with unilateral canal paresis due to vestibular neuronitis and sudden deafness, Meniere's disease and benign paroxysmal positional vertigo (BPPV). In the eccentric VOR at 0.32 and 0.6Hz, gain enhancement and phase lead were observed in the normal subjects. In the eccentric VOR, subjects were stimulated both by angular acceleration, as well as linear centrifugal and tangential acceleration, which act on the otolith organs. At 0.32 and 0.64Hz in this position, tangential acceleration showed a higher value than centrifugal acceleration. Therefore, we concluded that the gain enhancement and phase lead in the eccentric VOR were derived from tangential acceleration acting on the utriculus. The patients with vestibular disorders other than BPPV showed normal gain enhancement and phase lead at 0.32 and 0.64Hz. However, patients with BPPV, showed no gain enhancement or phase lead in 53.3% and 73.3% of the patients, respectively. It is suggested that BPPV results from incorrect response of the cupola in the posterior semicircular canal to gravitational changes due to otolithiasis. Therefore, the loss of gain enhancement and phase lead in the eccentric VOR in the patients with BPPV may be the result of utricular dysfunction.
To investigate the relationship between endolymphatic hydrops and otitis media, 34 patients with Meniere's disease and 26 patients with chronic otitis media received the glycerol test and electrocochleography. 1. It is desirable to examine mild endolymphatic hydrops not only with the glycerol test but also with electrocochleography. 2. Endolymphatic hydrops was found in 12% of the patients with chronic otitis media. Unlike Meniere's disease, this hydrops seems to be reversible in nature. 3. Active chronic otitis media, with auricular symptoms and pathological changes in the middle ear cavity, tended to be more frequently complicated by endolymphatic hydrops.
Schuknecht (1985) classified delayed endolymphatic hydrops (DEH) into three types, ipsilateral, contralateral and bilateral. The concept of DEH has been generally accepted; however, there is a problem that contralateral DEH might be unilateral Meniere's disease, accidentally appearing in on the ear opposite to that with severe deafness. In this paper the characteristics of contralateral DEH are compared with ipsilateral DEH and unilateral Meniere's disease. In the past 9 years 20 patients with DEH, 10 ipsilateral and 10 contralateral, were selected from among all the patients who had visited our clinic in the same period for a retrospective investigation of unilateral and bilateral severe deafness. Patients with unilateral Meniere's disease in the ear opposite to that with early onset of severe deafness, were included in the contralateral DEH. Three cases with contralateral DEH had no vertigo or dizziness with fluctuating hearing loss. Four patients with contralateral DEH had episodic vertigo; sensorineural hearing loss, which was of sudden onset in three, appeared from one to 10 years before the fluctuating hearing loss. Thus, in seven patients with contralateral DEH, cochlear disorders were the only symptom of DEH or preceded the onset of DEH. This tendency is different from the nature of the onset of Meniere's disease. In six of the nine patients with contralateral DEH (66%), endolymphatic hydrops was detected by the glycerol test, the ECochG and/or the furosemide VOR. Because not all patients were tested with all three examinations, the percentage of those with endolymphatic hydrops was lower than in those with Meniere's disease in our clinic (90%). In the four patients, who were tested with all three examinations, however, endolymphatic hydrops were demonstrated, There-fore we concluded that the number of findings pointing to endolymphatic hydrops in contralateral DEH was not very different from that in Meniere's disease. These results suggest that the characteristics of contralateral DEH may be different from those of Meniere's disease although both diseases have the same pathogenesis : endolymphatic hydrops.
Transdermal scopolamine (TTS-scopolamine) in the acute attack phase of Meniere's disease has been proved in our previous reports to be effective in alleviating vertigo and nausea. The effect of TTS-scopolamine on evoked nystagmus was evaluated in this study. Ten healthy adult volunteers, five male and five female, with a mean age 28.2 were examined. First, the following tests were performed : optokinetic nystagmus, rotatory induced nystagmus and caloric nystagmus. Optokinetic stimuli were given in 4°/sec2 in 30sec acceleration and deceleration each, without a pause. Rotatory induced nystagmus was provoked with acceleration and deceleration, first 60°/sec rotation in 0.5sec and deceleration in 30sec to standstill without a pause. Caloric stimulation was irrigation with 20°C for 20sec. Nystagmus was analyzed by counting the total number of beats, slow phase velocity and duration. After the application of two sheets of TTS-scopolamine over the mastoids the above procedures were repeated. TTS-scopolamine had no significant effect on any form of nystagmus, although the vertiginous sensation and nausea elicited with caloric stimmuli were decreased in most subjects. Although the present results did not clearly demonstrate an inhibitory effect on vestibular nuclei, TTS-scopolamine might partially block the pathway from the vestibular system to the central autonomic center.
Rehabilitation programs for patients with dizziness or dysequilibrium have been established empirically, so conventional rehabilitation programs have no theoretical support. In order to improve rehabilitation programs in the treatment of dizziness or dysequilibrium caused by various diseases, we studied an approach which is specifically selected to the cause of dizziness or dysequilibrium. A gait test was employed in our study, since walking is one of the fundamental activities of daily life. On a large floor with a dynamometer we tested the free gait of 125 healthy adults between 18 and 86 years of age. Multiple-step sampling was taken to find a tridirectional reaction force wave and a locus of bidirectional point of application force in order to analyze two factors; time-distance factor (velocity, stride, step width and cadence) and gaiting figure factor (symmetry, reappearance, smoothness and sway). The results indicated that the measured values of each parameter were inappropriate as a standard value due to great individual differences in eight parameters and statistically significant differences in sex and age. Nevertheless, this approach might be applicable to monitoring the process of gait development. Next we studied the correlation of these eight parameters, and found that certain combinations showed an absolute correlation, and other combinations showed no correlation regardless of sex or age. In particular, one parameter, cadence, correlated well with the other seven parameters and fulfilled the requirements of a standard. Therefore, cadence, which is deliberately controllable, was selected as the best parameter for practical use in rehabilitation programs.
To establish a reasonable, appropriate rehabilitation program to be used in the treatment of dizziness and/or dysequilibrium, the application of gait analysis to rehabilitation programs was studied. The previous study analyzed eight parameters in healthy adults : velocity, stride, step width, cadence, symmetry, reappearance, smoothness and sway. Cadence was found to be the most useful parameter. In the current study of 41 patients with confirmed Meniere's disease, the application of the cadence parameter was investigated further, in the gait test a patient is asked to walk in three different cadences; ordinary, faster and slower than the ordinary cadence. The relationship of cadence to the other seven parameters was studied. In patients with intermittent Meniere's disease without nystagmus, a gait pattern similar to that in healthy adulss was observed when cadence changed. On the other hand, in patients with Meniere's disease with nystagmus, the cadence tended to become faster than in healthy adults. It was also noted that cadence was associated with the figure of walking; the faster the cadence become, the worse was the figure. These results suggest that first patients should be trained to walk more slowly than usual, then as walking improves they should keep a constant stride, then change the speed in accordance with the cadence.
A rehabilitation schedule for patients with disequilibrium due to bilateral vestibular dysfunction is proposed and evaluated by the gravitational body sway test. Rehabilitation training includes : 1) Walk longer than 30 minutes daily; 2) Stand still with feet together and eyes closed for about 10 minutes in a room.Repeat 3 or 4 times daily. Body sway was recorded for 60 seconds with eyes open and 60 seconds with eyes and the bodily sway eight analysis with directional velocities was utilized. Two 70-year-old patients, 1 male and 1 female, were trained. The rehabilitation was contrnued for 40 month in the former and 35 months in the latter. After the training the two patients began to feel less unsteadiness and decreased velocity of gravitational body sway. However, when the rehabilitation was discontinued, the velocity of the body sway increased. Even with a simple program, rehabilitation can be expected. Its effectiveness must be determined quantitatively by stabilometry.