Three-dimensional analysis of morphological aspects of the human saccular macula.

The 3-dimensional shape of the human saccular macula and its orientation in the skull were quantitated in this study. The semicircular canals and saccular maculae were reconstructed 3-dimensionally on a computer from 3 human temporal bones. The 380 to 522 triangles in the entire area of the saccular macula were made by drawing lines between 2 adjacent points every 100-pm width of the saccular macula in each section. The angles between each triangle and each estimated standard axis in the skull obtained were calculated. This information will provide standard data regarding the 3-dimensional morphological aspects of the saccular macula for further investigations of the function of the sacculus. It was determined that the 3-dimensional shape of the saccular macula was not a plane, but was a curved surface like that of an ellipsoid. It is thought that this shape is necessary in order for the saccular macula to detect wide-range linear acceleration.

Basophilic deposits on the cupula: preliminary findings describing the problems involved in studies regarding the incidence of basophilic deposits on the cupula.

In this study, the possibility of whether basophilic deposits adhered to the cupulas in the semicircular canals was investigated histologically. Results indicated that basophilic deposits were present in all three cupulas of the semicircular canals. The overall incidence of basophilic deposits in the superior, lateral and posterior semicircular canal cupulas was 26%, 41% and 37%, respectively. The incidence of basophilic deposits bound to the cupulas increased with age. The possible origin of these basophilic deposits on the cupulas and the increased incidence of basophilic deposits with increasing age are discussed.

Influence of vestibular organ stimulation on stomach movement and respiration.

Some previous investigators have reported controversial results in the stomach movement in response to labyrinthine stimulation (1). The purpose of the present study was to investigate the influence of vestibular stimulation on the stomach movement and respiration in anesthetized cats, and to investigate the differences between increased and decreased responses of the stomach movement. This study used an electrophysiological technique: a bipolar stainless-steel stimulating electrode with a tip diameter of 20 microns introduced chronically into the anterior and/or lateral semicircular canal (2). The intragastric pressure was recorded by using a balloon-transducer system. Respiration was recorded by measurement of the thorax. When the peripheral labyrinth was stimulated, we found conflicting results in that the pressure in the stomach increased several times and sometimes decreased. Respiration usually became irregular or intensified. It seems that forced respiration may be involved in vestibular vomiting but we were unable to induce vomiting.

Vestibular training for acute unilateral vestibular disturbances: its efficacy in comparison with antivertigo drug.

We carried out a clinical trial on the treatment of acute unilateral vestibular disturbances (AUVD) without typical Meniere's disease and benign paroxysmal positional vertigo. Two therapy groups were selected: vestibular training (VT) with drug therapy and drug administration alone. After the experimental period of 8 weeks, all patients were classified into two groups depending on the methods of treatment, and the clinical courses of the patients were compared statistically. It was confirmed statistically by global judgments of symptoms and signs that improvement rates were higher in the group treated by VT with medication than the improvement rate in the group with medication alone. It is concluded that VT is effective for early relief from vestibular ataxia.

Optokinetic after-nystagmus in the human: a comparative study between normals and patients with peripheral vestibular and central disorders.

The purpose of this study was to classify various patterns of optokinetic after-nystagmus (OKAN) appearing in normal subjects, and to investigate the difference of OKAN between 147 normal subjects and 55 patients suffering from central nervous system (CNS) or peripheral vestibular disorders, in which 18 CNS disorders and 37 peripheral vestibular diseases were included. Data was divided into three categories by duration of the 1st phase of OKAN, i.e. hypo-response below 10 sec, middle response between 10 and 60 sec and hyper-response above 60 sec. The patterns of OKAN were then classified into six types with nine subtypes according to the following classification. All combinations of duration times of the 1st phase of OKAN toward both directions were then classified into six types, i.e. type 1, bilateral middle responses; type 2, bilateral hyper-responses; type 3, bilateral hypo-responses; type 4, unilateral hypo-response with contralateral middle response; type 5, unilateral hypo-response with contralateral hyper-response; and type 6, unilateral middle response with contralateral hyper-response. Moreover, subtypes "a" and "b" indicated symmetric and asymmetric in both types 1 and 2. Namely, if a relative value of the difference between bilateral responses against the sum of those was less than 20%, it was called "symmetric", otherwise, "asymmetric". Type 3 was divided into two subtypes: no response (3a) and hypo-response (3b). Results were summarized as follows. All combinations of horizontal OKAN toward both sides appeared in the 147 normal subjects. The incidence of each type, i.e. 1a, 1b, 2a, 2b, 3a plus 3b, 4, 5 and 6, was 10.9, 15.0, 2.7%, 1.4%, 25.2%, 31.3%, 4.1% and 9.5%, respectively. The incidence of type 3, type 3a in particular, was higher in patients than in the normals (p < 0.001). Also, the incidence of type 4 in normals was significantly higher than that of the patients (p < 0.01). Caloric tests revealed unilateral and bilateral canal pareses (CP) in 44 of 52 patients. The incidence of type 3 in the group of patients with CNS disorders was higher than those with peripheral vestibular disorders (p < 0.01). The 2nd phase of OKAN appeared in only nine of the 147 normals and in nine of the 55 patients. However, the 3rd phase of OKAN was observed in only one patient, the duration of which was 80 sec. The appearance rate of the 2nd phase of OKAN in patients was significantly higher than in the normal subjects (p < 0.05).

Initial symptoms and retrospective evaluation of prognosis in Menière's disease.

Clinical studies on an initial symptom and a long-term course of vertigo and hearing impairment and retrospective evaluation of the prognosis were performed in Menière's disease. One hundred and fifty-one patients (67 males and 84 females) with Meniere's disease were treated in the Neuro-otological clinic, Kitasato University Hospital from 1990 to 1995. Ages ranged from 17 to 77 years (mean 47.3 years) at the onset of the disease when the first vertigo attack occurred. There were 106 (70.1%) in their 30s, 40s and 50s, and 28 (18.5%) aged 60 years or over. Seventy-eight patients visited the clinic within one year of the onset of the disease, but the mean interval was 4 years and 5 months (the longest was 25 years). The mean duration time for the follow-up studies from the time of their first visit to the hospital was 2 years and 5 months. The bilateral ears were invaded in 19 patients (12.6%) and the mean length of their time course was 9 years and 10 months which is longer than the length in unilateral cases. Several important key points for diagnosis of Menière's disease were investigated in 28 of the 151 cases who had been followed up successfully over a relatively long time course (the mean follow-up time was 7 years and 3 months). Fluctuated or stational cochlear signs, such as tinnitus, hearing impairment and/or fullness in the ear, had started prior to the onset of the first vertigo attack in 17 (61%) of 28 cases. Vertigo without cochlear sign appearing at the onset and cochlear signs were combined later in six (21%) of the 28 cases. Only five (18%) of the 28 cases had vertigo combined with a cochlear sign simultaneously at the onset of the disease. The affected ear was on the left in 15 cases and on the right in seven of 22 unilateral cases. In six bilateral cases the left ear was the first to be invaded in four out of six cases. The interval between the first and second attacks was over 1 year in six of the 28 cases and over 6 months in 10 of the 28 cases. Nine out of the 28 patients had recurrence of vertigo attacks during the first month and five of the nine had a cluster of attacks in the first month. Our study of 28 patients over a long time course revealed eight patients (28.6%) free from the disease. These patients had no recurrence of vertigo for more than 2 years after their last attack, and sixteen (57.1%) of the 28 patients had no recurrence of vertigo for more than 1 year. However, a long period of relief time of more than 2 years in 11 of the 28 patients and a period of more than 1 year was noticed in 16 of the 28 patients. Hearing levels at the middle and low frequencies in the first hearing test were compared with the last test. The mean of hearing levels changed from 38.1 to 36.2 dB after 2 years and 1 month in six cases with the right ear affected and from 34.1 to 45.3 dB after 5 years and 3 months in 15 cases with the left ear affected, but in seven cases with bilateral diseased ears the hearing in both ears became worse, from 25.5 to 57.1 dB in the right ear and from 30.5 to 53.6 dB in the left ear during a period of more than 10 years. These clinical findings should be utilized for diagnosis at the onset of Menière's disease to determine the interval for observation in order to evaluate the efficacy of treatment.

Effectiveness of fibronectin in myringoplasty using temporal fascia.

A study of myringoplasty with temporal fascia homograft employing fibronectin was conducted in 14 ears in which the same myringoplasty procedure without fibronectin (1-5 times) had failed to afford closure of tympanic membrane perforation. Closure was obtained in eight ears. These results suggest that fibronectin is effective in myringoplasty using treated temporal fascia homograft.

Preliminary guidelines for reporting treatment results in Menière's disease conducted by the Committee of the Japanese Society for Equilibrium Research, 1993.

In order to draft guidelines for reporting treatment results in Menière's disease (MD) in Japan, 17 committee members elected from the Japanese Society for Equilibrium Research (JSER) have met for about two years. The preliminary guidelines obtained from their discussions are summarized as follows. i) Evaluations of symptoms: Only definitive vertiginous spells with spontaneous nystagmus should be evaluated (AAOO, 1972). The parameter for the assessment of hearing levels should be evaluated using four-frequency pure-tone averages (PTA) at 250 Hz, 500 Hz, 1 kHz and 2 kHz. ii) Evaluation period: Valid results for the evaluation should be based on observations at least six months before treatment and over at least 12 months after initiation of therapy. iii) Evaluation criteria The formula expressing the effects of treatment on vertiginous spells should adopt a numeric vertigo score, which is shown in the AAO-HNS (1985) guidelines. If the duration of pre-treatment evaluation period is less than 6 months, the divisor is replaced by the average of definitive spells per month for the period of observation. iv) Global judgment: For a global judgment, patients and doctors should jointly evaluate the treatment results from the standpoints of their subjective and objective symptoms respectively.