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In experimental autoimmune labyrinthitis, we found that the guinea pigs sensitized with bovine inner ear antigen (IEAg) developed cellular infiltration within the endolymphatic sac (E. sac). In this study, we investigated the distribution of immune mediated cells within bony vascular channels. The channels, which are normally found around the E. sac, are tiny and contain few immune-mediated cells. In contrast, in guinea pigs sensitized with IEAg bony vascular channels were large and contained immune-mediated cells. We hypothesize that immune-mediated cells in these channels are the result of the immune response directed against inner ear antigen, and that some immune-mediated cells seen in the E. sac during inner ear inflammatory events have migrated from the adjacent bone marrow.

We investigated the time course of hearing impairment and cellular infiltration into the inner ear after systemic sensitization of guinea Pigs with a single intradermal injection of bovine inner ear antigen (IEAg) in complete Freund's adjuvant (CFA). Lymphocytes and polymorphonucleocytes appeared mainly in the scala tympani on days 7 to 14, and in addition there was thickening and cellular infiltration of the round window membrane at day 14. These cellular infiltrations resolved after day 28. The auditory brain stem response thresholds from IEAg-sensitized animals were significantly elevated after day 7. Some sensitized animals (n = 5) had spontaneous remissions after day 28; however, the hearing thresholds did not completely recover. These results demonstrate that experimental autoimmune labyrinthitis can be induced by a single inoculation of IEAg-CFA and that remission, as evidenced by clearing of the cochlear cellular infiltration and improved hearing thresholds, can occur spontaneously.

• Three-component analysis of caloric nystagmus, focusing on the horizontal, vertical, and torsional, using a computerized eye movement analysis system, was carried out in 10 normal human subjects. The caloric response was induced by cold stimulation to the right ear of the subjects in the supine and prone positions. In the supine position, the three components of nystagmus were toward the left (10 subjects), upward (eight subjects) or downward (two subjects), and clockwise (10 subjects). In the prone position, on the other hand, the three components were directed toward the right (10 subjects), downward (five subjects), upward (three subjects), and counterclockwise (10 subjects); there was no vertical direction in two subjects. These findings indicate that caloric stimulation activates the three semicircular canals simultaneously. Also the changes in the nystagmus direction in the supine and prone positions could be explained, at least partially, by the nonconvective component of caloric stimulation. ( Arch Otolaryngol Head Neck Surg. 1992;118:1077-1080)

We examined the sera of patients with Meni-ere's disease or sudden deafness for inner ear autoantibodies using western blotting technique. The SDS soluble extract was prepared as the inner ear antigen from bovine inner ear tissues. Inner ear autoantibodies were found in 60% of the patients with Meniere's disease and in 59% of those with sudden deafness. Six patients had inner ear specific autoantibodies which reacted with 33-35kD determinants.Some patients wiht idiopathic sensorineural hearing loss, such as Meniere's disease and sudden deafness, may have autoimmune reactions directed against proteins derived from the inner ear. The presence of inner ear specific autoanti-bodies may enable the detection and treatment of autoimmune mediated inner ear disorders. It is now necessary to purify the inner ear specific antigens for the accurate diagnosis of autoimmune activity against the inner ear in patients with idiopathic inner ear disorders.

The sera of patients with idiopathic sensorineural hearing loss (SNHL) were examined, using qualitative immunoblotting (Western blotting), for the presence of inner ear (IE)-specific autoantibodies. The water-soluble extracts and the sodium dodecyl sulfate-soluble extracts were prepared as the antigens from bovine IE tissues and several other organs in order to determine the specificity of autoantibodies in their sera to the IE. Some patients (n = 46) tested had autoantibodies that reacted with 68-, 62-, 55-, 50-, or 47-kd antigenic determinants found in all tissues, while others (n = 13) showed IE-specific autoantibodies which reacted with 220-, 60-, 58-, 33–35-, or 32-kd determinants. The presence of these autoantibodies from patients with progressive SNHL may have important implications with regard to their etiology and possibly their sensitivity to therapeutic intervention. It is now necessary to purify these IE-specific antigens and determine their clinical usefulness.

The search for a diagnostic assay in patients with autoimmune inner ear disease has led to the preparation of antigens from the inner ear, a presumed target in this disorder. In order to standardize the antigen preparations currently being used in the Western blot immunoassay, we have examined several distinct extraction procedures that employ well-known solutions and detergents. Results of this investigation clearly show that antigens of interest (68 kd, 33 to 35 kd, and 32 kd) are optimally extracted with a detergent (0.5% sodium dodecyl sulfate) and that bovine serum albumin, a potential contaminant, can be removed in the water-soluble fractions. Purification of inner ear antigens by these methods will lead to more reproducible results in immunoblotting, as well as a greater opportunity to identify the mechanisms involved in autoimmune inner ear disease.

The relationship between the head size and the latency and amplitude of the auditory brainstem response (ABR) was investigated in 60 normal-hearing adults (30 males and 30 females). We found a strong positive correlation between the latency of ABR waves and the head size and a strong negative correlation surfaced between the ABR amplitude and head size. These results indicate that the head size is one of the most important factors influencing the waveform of the ABR.

• A new technique for an eye movement analysis system utilizing infrared video recording and a computerized image recognition method is presented. The system consists of an infrared lighting apparatus, a very small infrared video charge-coupled device camera, a video tape recorder, an analogue-digital converter, and microcomputers. This system makes it possible to simultaneously analyze the slow-phase velocity quantitatively not only of the horizontal and vertical but also of the rotatory components of the energy-induced nystagmus. The maximum slow-phase velocity of the rotatory component of energy-induced nystagmus was found to be 4.1° per second on an average in this study. ( Arch Otolaryngol Head Neck Surg . 1990;116:338-341)

In order to identify the inner ear autoantibodies, sera of 195 patients with sensorineural hearing loss and/or vertigo were reached with bovine inner ear antigen by western blotting method. Positive reaction was seen at several molecular weights, in which 33-35 kD, 42 kD and 68 kD were highly reactive. In moderate to severe hearing loss patients, positive reactions with 33-35 kD, 42 kD, 68 kD and others were 25.8%, 26.8%, 26.8% and 71.5% respectively. On the other hand, a positive rate did not clearly correlate with diagnostic entities. Further study to purify inner ear antigen may evaluate inner ear autoimmune disease.

In the previous report, we described the cause of the corneo-retinal potential increase after the optokinetic pattern test. We speculated that the rise of retinal activity in response to optokinetic stimulation leads to an increase of the potential. The present study is intended to confirm this speculation.Two optokinetic stimulus conditions were employed in this experiment. First, subjects fix their eyes on the stationary target during optokinetic stimulation without following black stripes. This induces mainly retinal stimulation (condition A). Next, subjects follow black moving stripes in the usual optokinetic test (condition B), which cause mainly foveal stimulation during low drum steed. Stimulus speeds of 30, 45, 60, and 90°/sec constant angular velocities were used.The corneo-retinal potential increased in condition A after all four stimulus speeds. In condition B, however, the potential did not increase after 30°/sec constant angular velocity stimulation.These data support the idea that the increase of corneoretinal potential after optokinetic stimulation is due to the rise of retinal cell activity.

The effect of band noise masking on persistent tinnitus was investigated in 191 patients. The effect of tinnitus masker was evaluated by the patient's complaints after two hours' masking. The causes of tinnitus in eluded pesbycusis, nose dnduced deafness, endlymphatic hydrops, sudden deafness sensorineural deafness of unknown etiology.The band noise masker was most effective on tinnitus due to presbycusis. Other influential factors in the effect of the tinnitus masker were age and hearing level at the tinnitus frequency. The suppression of tinnitus was more prominent in older patients and the patients whose hearing levels of the tinnitus frequencies were less than 30dBHL.