Spread of a tracer from the facial nerve to other cranial nerves was examined in eight rabbits. Sodium fluorescein solution was injected into the facial nerve trunk as tracer at the stylomastoid foramen and then localized by fluorescence microscopy. In the facial nerve, the fluorescence was consistently observed through the geniculate ganglion, but it was not observed in the proximal nerve root. The vestibular, trigeminal and glossopharyngeal ganglia also showed fluorescence in seven, two and two animals respectively. In these ganglia, fluorescence was seen in ganglion cells and intercellular connective tissue only on the injection side.
Ramsay Hunt syndrome consists of facial nerve paralysis and vestibulocochlear symptoms associated with vesicular eruption of the auricle and external auditory canal, and other cranial nerves such as trigeminal, glossopharyngeal and vagus nerves are occasionally involved. The mechanism of the spread of inflammation to these cranical nerves has not been sufficiently clarified. Although the spread of the tracer into the spiral ganglion could not recognized, the fluid pathway from the facial nerve to these cranial ganglia seems to be associated with a neural spread of infections.

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We investigated species difference in cochlear dysfunction associated with experimental perilymphatic fistula using guinea pigs and chinchillas. The tone-burst elicited compound action potential (CAP) was studied in order to compare cochlear damages caused by an identical experimental method for perilymphatic fistula between the two species. A significant elevation of CAP threshold following laceration of the round window membrane was restricted to the highest frequency (12 kHz) in both species. Subsequent perilymphaspiration caused further CAP threshold elevation throughout all tested frequencies (2, 4, 8 and 12kHz) in both species. However, chinchillas showed greater threshold changes than guinea pigs. Histological examination revealed a rapture of the Reissner's membrane in two chinchillas with substantial CAP threshold changes following perilymph aspiration. These results indicate that cochlear of guinea pigs are less susceptible to experimental perilymphatic fistula than those of chinchillas.

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Numerous papers have been published on otitis media with effusion (OME) in children, but few have concerned the aged. The clinical featuers and prognosis of OME in the aged were assessed in this study. We reviewed 74 patients over 50 years old with OME (96 ears).
Such findings as unilateral morbidity (68%) and serous effusion were common (86%) in this aged group. It was discovered that many aged patients had highly pneumatized mastoid air cells. Air conduction hearing levels had declined an average of about 27dB in the affected ears, but bone conduction was not affected by OME. The diminished air conduction recoverd after myringotomy or ventilation tube insertion.
Recurrence of OME was observed in 40% of the 85 ears treated. Recurrence was difinitely more frequent following myringotomy and a straight tube insertion than after bobin-shape tube insertion. The recurrence rate was significantly higher in patients with large mastoid air cell systems or chronic sinusitis, and lower in patients treated with a long-term ventilation tube.
It was concluded that long-term ventilation tubes are appropriate initial treatment, especially in the aged OME patients with well-developed mastoid cells or chronic sinusitis.

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76 operated cases of chronic otitis media were classified into three groups.
Group I: all of pre-operative diagnosis, diagnosis during surgery and histopathological diagnosis were aural cholesteatoma (37 cases).
Group II: one or two of the pre-operative diagnosis, the diagnosis during surgery and the histopathological diagnosis were cholesteatoma (12 cases).
Group III: all of the pre-operative diagnosis, the diagnosis during surgery and the histopathological diagnosis were chronic otitis media without cholesteatoma (27 cases).
Comparing several office examinations of these three groups, otoscopic examination was most useful for confirmation of cholesteatoma. Most cases of Group I had a posterior retraction poket or marginal perforation.
Possibility of misdiagnosis during surgery was that cholesteatoma was not found under a microscope because the size of cholesteatoma was too small or cholesteatoma was intermingled with granulation.
There was a possibility of histopathological misdiagnosis when a mixture of the middle ear tissue and the squamous epithel tissue, such as the outer layer of the tympanic membrane or the skin of the external auditory canal, were submitted for histopathological studies.
The important point was that not only the cases in Group I but also the cases in Group II needed sufficient post-operative observation.

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Case 1: A 37-year-old female with mental retardation presented with hearing loss and otalgia in the left ear for 2 months. Otoscopic examination revealed polypoid granulation tissue and otorrhea. The eardrum was not visualized due to severe swelling of the posterior meatal wall. CT of the temporal bone showed a diffuse soft tissue density extending from the bottom of the external auditory canal to the mastoid cavity with calcified tissue in the external auditory canal and the mesotympanum. Surgical exploration revealed foreign bodies most likely fragments of small stone in the external auditory canal accompanied by inflammatory granulation tisse.
Case 2: A 13-year-old boy complained of recurrent otorrhea and hearing impairment of 3 months' duration. Otoscopic examination revealed polypoid granulation tissue in the external auditory canal. The whole eardrum was not observed due to the narrow external auditory canal. CT of the temporal bone showed a diffuse soft tissue density from the mesotympanum to the mastoid cavity. Surgery of the ear revealed foreign bodies most likely white-yellowish beans in the mesotympanum, and hemorrhagic granulation tissue extending from the mesotympanum to the mastoid cavity.

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In 88 ears with adhesive otitis media, 46 men and 37 women aged six to 66 years, postoperative hearing results and the condition of tympanic membrane were analyzed. Follow-up examination was carried out six months to 17 years after operation. One stage tympanoplasty was performed in 70 ears and the planned staged tympanoplasty in 18 ears. Overall success rate in hearing was 55%. Regarding the postoperative condition of the tympanic membrane. 53 ears (60%) showed normal, 26 ears (30%) re-adhesion and nine ears (10%) perforation. The normal rates of post operative condition of the tympanic membrane in each operative procedure to avoid re-adhesin of tympanic membrane were 100% in transplantation of mastoid mucosa to the middle ear, 7.5% in the use of nasal cartilage to strengthen the atrophic membrane and 71% in the use of Gelfilm. Tympanoplasty Type I, with columella Type III and with columella Type IV were performed in 34, 25 and 15 ears and the success rates in hearing were 62%, 56% and 33% respectively.

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A 10-year-old boy developed ageusia of the left anterior portion of the tongue following head contusion induced in traffic accident. Gustatory function testing (electrogustatometry and filter-paper disk gustation test) revealed ageusia in the portion of the tongue innervated by the left chorda tympani nerve. However, the patient had neither middle ear disease nor facial nerve palsy. Movement and tactile sensation of the tongue were normal, and there was no other cranial nerve disorder. X-ray and CT scan examination of the left temporal bone disclosed no evidence of fracture. This patient was diagnosed as a rare case of isolated disorder of the chorda tympani nerve. Treatment with steroid hormone, B complex vitamins, zinc sulfate and theophylline resulted in a complete recovery of gustatory sensation in three months.

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A 25-year-old man complained of hearing loss and vertigo occurred just after injuring the left ear drum with an ear pick. Pure tone audiometry showed a mixed hearing loss of 70.0dB. Vestibular function tests showed positional nystagmus. Exploratory tympanotomy was performed on 19 days after the onset following conservative therapy. Incudo-stapedial joint was dislocated and perilymphatic leakage from the oval window was observed. The window membrane was repaired with temporal fascia and ossicular chain continuity was reconstructed. Postoperatively hearing and vestibular symptoms were improved. This case suggested that immediate operation should be carried out in case that inner ear symptoms caused by direct trauma do not respond to conservative therapy.

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This study was performed to evaluate the usefulness and limitations of three dimensional (3-D) imagings of stapes in the middle ear by high speed helical CT.
One dissected human temporal bone, ten normal and diseased ears were scanned with a slice of 1.0mm and reconstructed in a thickness of 0.2-0.5mm.
Every specimen of 3-D CT can be observed in any plane and from any direction. Ossicular imagings of the temporal bone in 3-D CT were reconstructed as if the malleus, incus and stapes were observed under microscope. The whole structure of stapes was impossible to be represented by two dimensional CT heretofore in use, but 3-D CT in our study showed the head, crus and foot plate of the stapes in detail.
Stapedial imagings of 3-D CT in normal ears showed the same findings as those recorded in temporal bone. Preoperative diagnostic findings of ossicles in the affected ears were very usefull. Especially in ossicular anomalies, 3-D CT was positive in diagnosis and its accuracies were confirmed with operative observation. For the postoperative evaluation concerning the ossicular reconstruction, i.e, TORP and PORP, 3-D CT was also important method. It could present an anatomical relation between those prosthesis and the oval window.
High speed helical CT can scan an object more quickly and clearly than formerly used CT, and its biological damage for human is less than that of the others. 3-D CT can be more clearly reconstructed with helical CT than former CT.

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A 55-year-old-male presented with a complaints of right otorrhea and hearing disturbance since his childhood. Otoscopic examination showed a cholesteatoma and granulation tissue in the attic retraction. CT scan revealed a high jugular bulb protruded to the tympanic cavity. Tympanoplastic surgery was done in his right ear. When the right ear drum adhered to the promontrium was dissected, profuse bleeding was encounterd from the postero-inferior portion of the tympanic cavity. Bleeding was so severe that was not able to controled by pressure. A piece of temporal muscle was packed into the bulb, and bleeding was controled.

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A 60-year-old male suffered from left temporalgia and developed mastoiditis. A jugular foramen syndrome (cranial nerve IX, X and XII deficit) that occurred in spite of mastoidectomy was improved by means of dissection of petrosal part.
One month later. at the contra-lateral side of the jugular foramen syndrome, Gradenigo syndrome originated from mastoiditis occurred. Mastoidectomy resulted in improvement of clinical symptoms.
Five months after the surgery, the patient developed left superior orbital fissure syndrome (cranial nerve II, III and V palsy) with thickening of the dura mater which was demonstrated by Gd-DTPA MRI.
Corticosteroid therapy was effective except for blindness.
These clinical findings of cranial nerve palsies were suspected to be associated with the migrating disseminated multiple cranial neuropathy.

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In most of tinnitus clinics in Japan, tinnitus freqency and tinnitus nature (tonal or noise) have been examined according to the method described in Standerdized Tinnitus Test in 1984 which proposed the rough pitch match test with an octave step between 125Hz and 8kHz using a pure-tone audiometer as a standard evaluating procedure. Although this method is simple and the repeatability of test results is excellent, tinnitus frequency and tinnitus nature can not be investigated precisely because of the limited number of tinnitus simulated tones in a pure-tone audiometer. Therefore, a tinnitus analyser (TH-10) was recently developed by RION Company to investigate tinnitus pitch and tinnitus nature more precisely. This tinnitus analyser can produce pure-tones and 3 kinds of band noise (BN) with various band widths (BN1, BN2 and BN3) at 11 frequencies between 125Hz and 12kHz as tinnitus simulated tones.
We conducted tinnitus tests (pitch match test, loudness balance test and masking test) by this tinnitus analyser in 70 tinnitus ears without hearing loss or associated with sensorineural hearing loss of various causes and obtained the following results.
1) The tinnitus simulated tone in pitch match test was BN1 or BN2 in 9 tinnitus ears out of 70 (12.9%), which could not be produced from a pure-tone audiometer.
2) The tinnitus frequency was found to be at 10kHz in 9 tinnitus ears out of 54 (16.7%) in which the tinnitus frequency was clearly identified.
3) The tinnitus loudness indicated by sensation level was distributed between 0dB and 20dB (mean: 3.9dB). There was no clear difference of loudness between this result obtained by TH-10 and the previously reported ones obtained by a pure-tone audiometer.
4) The masking level indicated by sensation level was distributed between 0dB and 35dB (mean: 12.9dB). There was no clear difference of masking levels between this result obtained by TH-10 and the previously reported ones obtained by a pure-tone audiometer.
5) When the results of pitch match test by TH-10 were compared between ipsilateral and contralateral evaluations in 34 unilateral tinnitus ears, the excellent correspondence of tinnitus frequency and tinnitus simulated tone was found between them in most of the subject ears.
6) When the results of pitch match test by a pure-tone audiometer were compared with those by TH-10 in 18 tinnitus ears, tinnitus frequency and tinnitus simulated tone were clearly identified by TH-10 in 3 tinnitus ears out of 7 (42.9%) in which the tinnitus could not be simulated by a pure-tone audiometer.
7) Based upon these results, it was concluded that the tinnitus pitch match test by a tinnitus analyser (TH10) enables us to investigate tinnitus frequency and tinnitus nature more precisely than by a pure-tone audiometer, and also this tinnitus analyser (TH-10) is suitable to evaluate tinnitus nature according to the method described in Standardized Tinnitus Test in 1993 which was recently proposed by Tinnitus Study Group of Japan Audiological Society.

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The relationship between click evoked otoacoustic emission (EOAE) and distortion product otoacoustic emission (DPOAE) was investigated. The subjects were 42 ears with cochlear deafness of various causes which showed the pure-tone hearing level of 35dB or more at one or more frequencies between 125Hz and 8kHz.
The EOAE was elicited by non-linear clicks of 82±1dBSPL produced from the Otodynamic Analyser ILO88D (Version 3.51) and the FFT analysis of the EOAE wave was conducted. Three parameters such as total echo power (TEP), highest peak power (HPP) and frequency area peak powers (FAPPs) in 6 frequency areas were analyzed.
The DPOAE was recorded by the Otodynamic Analyser ILO92 (Version 1.31). The F₂/F₁ratio was fixed between 1.18 and 1.20 and the DP level at 2F₁-F₂was investigated at 14 F₂points between 708Hz and 6299Hz. The stimulus intensity of primaries was fixed to 70dBSPL at F₁and 60dBSPL at F₂, respectively. Three parameters such as total DP level, highest DP level and DP levels at individual F₂points were analyzed.
The results obtained were as follows;
1) When the relationship between TEP in EOAE and total DP level in DPOAE was investigated, a significantly positive correlation was found between them (r=0.65).
2) The HPP in EOAE and highest DP level in DPOAE also showed the significantly positive correlation (r=0.63).
3) When the FAPPs in 6 frequency areas of EOAE and DP levels at 14 F₂points of DPOAE were compared, they showed the highestly positive correlations in corresponding frequency areas.
4) It was suggested that both EOAE and DPOAE could be derived largely from the similar generation mechanisms within the cochlea.
5) The simultaneous recordings of both EOAE and DPOAE could enable us to evaluate objectively the frequency-specific cochlear function in a wide frequency range in the ears with sensorineural hearing loss.

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Distortion product otoacoustic emission (DPOAE) was investigated in 10 persons with bilateral normalhearing and in 10 with unilateral cochlear deafness. DPOAE was recorded by an Otodynamic Analyser ILO92 (Version 1.31) which was recently developed by Kemp. The F₂/F₁ratio was fixed between 1.18 and 1.20 and the DP level at 2F₁-F₂was investigated at 14 points of F₁between 598Hz and 5273Hz and F₂between 708Hz and 6299Hz. The stimulus intensity of primaries was fixed to 70dBSPL at F₁and 60dBSPL at F₂, respectively. The distortion product-gram (DP-gram) was drawn from the DP levels at 14 individual F₂points.
The results obtained were as follows;
1) DPOAE with high level was obtained even in high frequency areas above 4kHz in all normal-hearing ears.
2) There was a relatively large intersubject variance in the DP level at 14 individual F₂points and also in the configuration of DP-gram in normal-hearing ears.
3) When the averaged DP-gram was drawn from the individual DP-grams in 20 normal-hearing ears, the mean DP level was the highest around 5kHz. The mean DP level below 1kHz was found to be low.
4) The interaural defference of DP levels at 14 individual F₂points and that of the configuration of DP-gram was found to be minimal in the persons with bilateral normal-hearing.
5) The short-term reproducibility of DP levels at 14 individual F₂points and that of the configuration of DP-gram in consecutive repeated tests was excellent in normal-hearing ears.
6) DPOAE could not be elicited in the frequency areas with 50dB or more of pure-tone hearing level in cochlear deafness.
7) When the relationship between pure-tone audiogram and DP-gram was analysed in cochlear deafness, the excellent correspondence with frequency specificity was found between them.
8) Based upon these results, it was concluded that DPOAE could be a very useful clinical tool for objective investigation of the frequency-specific cochlear function in the ears with sensorineural hearing loss.

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