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With the increasing long-term use of interferon (IFN), several new adverse effects have been recognized. Very little attention, however, has been paid to auditory acuity. We encountered 3 cases of sudden hearing loss associated with IFN. We then conducted a prospective study to assess the auditory function of 73 patients receiving IFN. Auditory disability (tinnitus and/or hearing loss) occurred in 32 patients (43.8%) during IFN therapy, among which audiometry documented sensorineural hearing loss in 27 cases (36.9%); 17 (48.6%) of the 35 patients receiving IFN-beta had auditory disability, including hearing loss in 13 cases (37.1%), and 15 (39.5%) of 38 patients receiving IFN-alpha suffered from auditory disability. There was not much difference between the influences of IFN-alpha and -beta. Auditory disability frequently developed in the later stages of treatment, and most patients recovered 7-14 days after the discontinuation of IFN. The results demonstrate that sudden hearing loss can occur as a side effect of treatment with IFN. This may reveal the association between autoimmunity and sudden hearing loss.

Laryngomalacia is usually a benign condition which occurs soon after birth, and is resolved by 2 years of age. A 12-year-old female, with a history of nasal allergy, had complained of inspiratory stridor and cough. Laryngoscopy revealed a flaccidity of all the supraglottic structures. The arytenoids and aryepiglottic folds were fluttering during inspiration. The stridor was improved after resecting the excess tissue with a CO2 laser. A barking cough appeared about 10 days after the operation and placebos were effected to it. We suggest that she had a tendency to inspiratory laryngeal collapse and that her symptoms might have been triggered by allergic and/or psychological factors.

Changes in vascular permeability to sodium fluorescein following experimentally induced nerve le- sions were examined in the rabbit facial nerve. Sodium flu- orescein was injected intravenously as a permeability tracer and then localized by fluorescence microscopy. In control nerves, endoneurium showed only slight fluorescence while intense fluorescence was observed in the epineurium and perineurium. In nerves demonstrating edema and Waller- ian degeneration, endoneurium was found to have an in- creased accumulation of tracer. This increased endoneur- ial vascular permeability in facial nerve lesions may ex- plain nerve enhancement seen in gadolinium-enhan ced magnetic resonance imaging in patients with facial nerve paralysis.

Recently, it has been reported that the facial nerve shows enhancement on gadolinium-enhanced magnetic resonance imaging (Gd-MRI) in patients with such conditions as Bell’s palsy or traumatic facial nerve paralysis. The site of involvement in Bell’s palsy remains unknown, and accurate lesion-site information is useful for surgical planning in cases of facial nerve paralysis. The importance of this technique in detecting the lesion site has been discussed, but the mechanism of facial nerve enhancement is unknown. In the present study, in order to elucidate the correlation between facial nerve enhancement and lesion site, Gd-MRI study was performed in the rabbit.

The alteration of motor neurons in the brainstem after recovery from experimental facial nerve paralysis was examined by the retrograde horseradish peroxidase (HRP) technique in the rabbit. Six months after nerve crush injury at the center of the vertical portion, HRP was injected into the zygomatic muscle on the recovered side. The distribution of labelled neurons in the brainstem was compared with that in the normal rabbit. In control animals, motor neurons in the facial nucleus were somatotopically organized, and there were no labelled neurons in other nuclei in the brainstem. In recovered animals, on the contrary, the somatotopic organization of the facial nucleus was obscure and multipolar neurons of varying size were labelled bilaterally in the reticular formation from the pons to the medulla.

Experimental positional nystagmus (EPN) similar to benign paroxysmal positional nystagmus (BPPN) was induced in 8 of 20 rabbits by argon laser irradiation to the footplate. The power of the argon beam used was 2.0 watts and irradiation time was 1 or 2 sec. EPN and BPPN showed the following similarities maintained (1) When the head was maintained in the affected ear down position and the head positioned from the sitting to the supine position nystagmus directed to the affected ear or vertical nystagmus corresponding to rotatory nystagmus in man were provoked. (2) Delayed onset for provocation of nystagmus. (3) Limited duration. (4) Fatigability. (5) The direction of nystagmus was reversed when the head returned to the initial position (in two rabbits). Histological examination of the temporal bones showed separation of otoconia from the otolithic membrane of the saccule and bleeding in the saccule in both conditions. No lesions in the utricle and semicircular canals were evident. It was assumed that ablation of otoconia of the saccule causes this experimental positional nystagmus.

• Auditory nerve action potential (AP), cochlear microphonics (CM), and summating potential (SP) were recorded from 32 patients with Meniere's disease. Patients were classified into three groups according to the degree of their hearing impairment. The group of patients that had a mild to moderate hearing loss and whose hearing was reversible showed notably satisfactory responses for AP, CM, and negative SP (-SP), and also showed a high incidence of positive SP (+SP). Low responses for AP and CM with an increase of detection thresholds and a high -SP/ AP ratio were obtained from patients with moderate hearing impairment, whose hearing fluctuated slightly. These electrocochleographic findings were suggestive of the pathophysiologic differences at the various stages of Meniere's disease. ( Arch Otolaryngol 1982;108:284-288)

Experimental vestibular disorders of the peripheral type were induced using transtympanic infusion of several drugs. Drugs with high specific gravity such as saturated sodium chroride and pottasium chroride, heavy water, ethylene glycol, glycerine, isosorbid and urea induced direction-changing, positional nystagmus. The nystagmus was directed upward when the head was held with the right or left side down, to the injected side with the nose-up, to the non-injected side with the nose-down position, respectively. Ethyl-alcohol and aceton which have low specific gravities also induced direction-changing, positional nystagmus, although the direction was opposite to that of those drugs with high gravities.Most of these positional nystagmus developed to paralytic nystagmus which directing toward the non-injected side in all head positions or disappeared in three hours. Some animals had a second phase of positional nystagmus before it disappeared. Only pottasium chroride produced irritative nystagmus which directing towared the injected side in all positions and changed to paralytic nystagmus.

Five patients with episodic vertigo, tinnitus and hearing loss were found to have compression of the eighth cranial nerve by small aneurysm or arterial loops.The characteristic symptoms in these patients were :1) Short term and sudden-onset vertigo occurring frequently and not responding to medical treatment.2) Patients became asymptomatic immediately when the attacks ended.3) Hearing loss fluctuated widely but briefly at low or wide frequency ranges.4) In some cases there were associated ipsilateral facial spasms and/or trigeminal neuralgia.5) Nausea and vomiting during the vertigo attacks were less prominent than with Meniere's syndrome.6) Severe and frequent attacks were observed even, in patients with severe semicircular canal palsy.7) Vertebral angiography showed elongation and enlargement and sharp angulation of the fourth segment of the vertebral artery on the affected side.

A patient with Tullio's phenomenon of the right ear was tested with infrasound through the auditory canal which was generated at 100115dB SPL of 1545Hz by an ear drum massager. Nystagmus towards the right was recorded on ENG when the infrasound was produced in the right ear and it shifted to the left when the infrasound was interrupted, but no nystagmus occurred when the left ear was exposed to infrasound. In stabilometry tests the area of the stabilogram was increased significantly when infrasound was produced in the right ear, but it was normal when the left ear was exposed to infrasound. These findings were believed to be elicited by the transmission of pressure from the ossicles to the membranous labyrinth which was speculated to be distended by endolymphatic hydrops. Probe tympanotomy was performed, and no abnormality of the middle ear was noted, but the symptoms of Tullio's phenomenon disappeared postoperatively.

The cases with low tone sensorineural deafness were studied using the transtympanic-electrode technique of electrocochleography.The results obtained were as follows:1) Low tone sensorineural deafness of sudden onset without vertigo:All the cases showed high AP and -SP amplitude and satisfactory CM response. These findings resembled the electrocochleographic findings of type I of Meniere's disease suggesting of the relationship with endolymphatic hydrops. The hearing returned to normal range in a half of the cases but remained hardly changed in the other half. The difference between these two groups could not be clarified electrocochleographically.2) Familial progressive deafness showed low tone sensorineural deafness:This case showed a high threshold and a low amplitude of CM at low frequency, and showed cochlear hair cell damage at low frequency range.3) Low tone sensorineural deafness due to retrolabyrinthine lesion:This case showed a normal CM but a low AP amplitude, and lacked a rapid increase of AP amplitude with increasing click intensity in the intensity region of AP input-output functions.

Two hundred and eight cases of benign paroxysmal positional vertigo (BPPV) were studied.The number of patients with BPPV has increased recently, especially those over 60 years of age.Head injury, hypertension, prolong bed rest and administration of streptomycin were significant causative factors.A neurotic tendency was more evident in BPPV patients than in normal subjects, but less than in those with Meniere's disease.The change in direction of positioning nystagmus between the sitting and the hanging position, which is supposed to indicate the pathology of the side, coincided with the side of semicircular canal palsy, critical position, hearing disturbance, etc. in 57%-74%.Vertigo disappeared in 40% of the case within the first week and in 40% more within the first month, but BPPV recurred in 30%.Physical exercise was very effective in the treatment of BPPV.

Decompression operation was performed on patients with Bell's palsy and facial nerve palsy due to temporal bone fracture or otitis media, and a study was made on the relation between the fluorescence findings of the nerve and prognosis. The fluorescence of nerve was visible in 4 cases of Bell's palsy but none of the patients was completely cured, though the degree of cure tended to be proportional to the intensity of fluorescence. On the other hand, cure was seen even in cases of facial nerve palsy due to temporal bone fracture or otitis media that showed no fluorescence or any response in the maximal stimulation test (MST). It is suggested that Bell's palsy and facial nerve palsy due to trauma or otitis media do not share the same pathophysiology.

Electrocochleography was performed on six patients with posterior cranial Fossa tumors which consist of three cases of acoustic neurinoma of grade II-III, a case of glioblastoma multiforme originating from cerebello-superior pons, a case of astrocytoma of grade III originating from medulla oblongata-inferior pons, and a case of meningioma originating from Meckel's cavity. Recording was made with the use of the transtympanic needle technique. AP input-output functions with acoustic neurinoma were very similar to those obtained in patients with sensorineural hearing loss showing the phenomenon of recruitment. In AP responses recorded from the patients with cerebello-superior pontine tumor and Meckel's cavity tumor, a loss of the positive portion of the potentials (P1) was characteristic. This phenomenon may be due to the compression on the auditory nerve by the growing tumor. The polarity of SP in all cases showed negative deflection without abnormal increment. CM responeses recorded from the patients were the same as in a normal subject. In the cases presented, although the abnormal changes in input-output functions as well as the changes in the wave form patterns of AP responses revealed a lesion of the portions corresponding to the sensory and/or to the neural structure, the presence of a well-developed CM may be explained by the fact that the hair cells remain unaffected. Therefore, it is thought that simultaneous recording of CM and AP gives great promise as a means of differential diagnosis between neural and cochlear pathology.

In the study on regional difference in susceptibility to damage of vestibulosemicircular canals upon causing labyrinthine lesion by four different procedures, namely, by intracranial approach, through the middle ear, through the facial nerve and by means of experimental endolymphatic hydrops, the following results were obtained. 1. The crista of posterior semicircular canal among the semicircular canals and the macula of the saccule within the vestibule were most susceptible to impairment. In other words, the most susceptible region was the so-called pars inferior. In regard to the impairment of the cupulas, the posterior semicircular canal was the most susceptible region. 2. 2. Recovery from markedly reduced caloric nystagmus within a short period so as to see provocation of caloric nystagmus may result from the reconstruction of the cupulas and the normalization of vacuole-like findings of the sensory epithelium.

The purpose of this paper is to demonstrate the variation of the direction of nystagmus which is elicited from the peripheral labyrinth. The direction of nystagmus depends, among other things, on the nature of the stimulus. Depending on the degree of pathophysiological conditions in the labyrinth, atypical nystagmus which does not comply with the rule is occasionally elicited even though the same stimulus is given. Hyperfunctional stimulation to the labyrinth, such as allergy, causes nystagmus which beats to the affected side and also shows hyperactivity of the whole nerve action potential and cochlear microphonics.

The authors observed eight cases of intermittent tinnitus which appeared during the course of recovery from peripheral facial nerve paralysis of various etiology. The tinnitus occurred whenever a certain mimic facial muscle contracted voluntarily or involuntarily.As the tinnitus in each case didn't dispaaeared by medical treatment or other conservative therapy, tympanotomy via extenal auditory meatus was made. Under the operating microscope, contraction of the stapedius muscle synchronous with contraction of the mimic facial muscle was observed. The tinnitus had disappeared completely immediately after the tendon of stapedius muscle was sectioned. Thus the existence of tinnitus due to abnormal contraction of stapedius muscle was confirmed.Further, tinnitus in each cases was considered to be an expression of abnormal associated movement involving the stapedius muscle during the course of the recovery from facicl nerve paralysis.Changes of the minimum audible. threshold (air conduction) were measured in each case during the stapedius muscle contracted without sound stimulation, and the results showed a good accordance to the results obtaind from the theoretical and experimental works which had been reported by several authors.In a conclusion, the authors stressed the importance of the stapedius muscle tinnitus in the study of pathogenesis of tinnitus, facial nerve paralysis, as well as in the study of middle ear function.

The authors observed eight cases of intermittent tinnitus which appeared during the course of recovery from peripheral facial nerve paralysis of various etiology. The tinnitus occurred whenever a cert

Barium sulfate was used to study foreign body reaction of the nasal sinus. This substance possesses strong foreign body effect and to the mucous membrane and produces remarkable swelling of the sinus mucosa after instillation into the antrum and the swelling of the sinus membrane can be demostrated roentgenologically.The observation was carried out on the chronic sinusitis patients. X-ray film was taken 24 hours after instillation of barium in the maxillary sinus in 77 cases, and also on the 8th day in 88 cases. All cases were operated after the roentgenological examination. The changes on X-ray films were com pared with that of obtained histological specimens. From this study the following results were obtained: The swelling of the membrane was most remarkable in mild cases of chronic sinusitis which showed minimal swelling of the mucosa on X-ray film. In the cases with extensive rnucosal changes, no reaction to barium was seen.On the other hand, swelling of the mucosa was remarkable in the cases with large sinuses, while it was not so severe in the cases with small sinuses.This reaction of the mucosa consists of edematous swelling and round celhnfiltration with increased eosinophils. Those findingsin the mucosa resembles to the picture of the edematous type of chronic sinusitis. Allergy test proved to be negative in the cases with marked mucosal reaction.The author has previously stated that this reaction of the mucosa could be ascribed to the foreign body effect of the Ba SO4, and not to its chemical stimulation. The mucosal change in chronic sinusitis might be the result of foreign body effect of the infected bacteria which have relatively weak toxisity. This study revealed that the mucous membrane of the sinus displayed different reactions against the same stimuli depending on its grade of pneumatization. The well-developed large sinuses reacts foreign body with edematous change, but this reaction is minimal in the under-developed small sinuses. This reaction against foreign body should be recognized as that of the sinus itself, because the foreign body was insilled in the sinus cavity and not in the mucosa.The author would like to emphasize that this results of the clinical study can serve as the valuable data to understand pathology of chronic sinusitis. Unfortunately our experiment of similar foreign body reaction in rabbits failed to find significant change to confirm these clinical findings.

Auditory nerve action potential (AP), cochlear microphonics (CM) and summating potential (SP) were recorded from 6 patients with low-tone hearing loss without vertigo. All these cases showed high AP and -SP amplitude and satisfactory CM response. These findings resembled the electrocochleographic findings of type 1, which is an early stage of Ménière's disease. Hearing returned to normal range in half of the cases but remained hardly changed in the other half. The difference between these two groups could not be clarified electrocochleographically. On the other hand, low-tone hearing loss due to retrolabyrinthine lesion and due to familial sensorineural deafness was shown to have a low AP amplitude.

• Electrocochleographies were performed on three patients with deafness resulting from cerebral vascular lesions. Recording was made by the transtympanic needle electrode technique. In a patient who had anterior-inferior cerebellar artery aneurysm that showed fluctuating hearing loss, auditory nerve action potential (AP), cochlear microphonics (CM), and summating potential fluctuate in amplitude in concert with episodes of ischemic hearing loss. This indicates the pathophysiology of reversible impairment of the cochlear nerve and of sensory epithelium of the inner ear caused by disturbance of blood flow into the inner ear. It was also conjectured that the cochlea is hardly impaired in the case with normal AP and CM responses despite the increased threshold in pure-tone audiometry and that the cochlea undergoes irreversible organic changes in the patient who has no AP or CM response in tests after a long period. ( Arch Otolaryngol 107:74-78, 1981)

In experiments using rabbits, the pupil on the side of irritative inner ear lesion showed dilatation, and that on the side of paretic lesion showed constriction. In the clinical observation of patients with unilateral inner ear diseases (134 cases), anisocoria was recognized in 54.5%. In 68.5% of these, anisocoria was induced after applying a drop of neosynephrine. The size of the pupil on the healthy side was smaller in 65.8% than the pupil on the healthy side. Anisocoria in inner ear lesions is believed to be due to vestibulo-sympathetic imbalance through the superior cervical sympathetic ganglion.

This study was conducted to elucidate the pattern of clinical recovery from partial facial palsy caused by injury to a branch of the facial nerve in rabbits. In the experiment, the state of recovery from palsy was investigated by observing the movement of the m. orbicularis oris of the rabbit at the time of food intake, as well as by observing the evoked wave and muscle contraction caused by nerve stimulation, and the muscle contraction caused by muscle stimulation. Recovery from peripheral facial nerve palsy is complete within 1 month after nerve impairment if over half of the nerve fibers of the impaired nerve are maintained intact without degeneration.

It has been observed through our clinical experience and experimental results that a com-plete recovery of muscle paralysis can not be expect after a severe damage to the innervating nerve, even after evidence of regeneration of the nerve fibers is ascertained. Why does such a condition occur? How much muscle impaired after a nerve was crushed or sectioned? The purpose of this study is to answer to these questions. After the third branch of the facial nerve of rabbits was sectioned to the depth of 1/4, 1/2, 3/4 and then 7/8 in diameter, the degree of muscle contraction induced by stimulating the nerve central to the lesion was evaluated by means of a UL-type strain gage. Moreover, 8 months after the third branch of the facial nerve of rabbits was crushed or sutured after sectioning, the muscle contractibility was estimated and the pattern of evoked waves obtained from the orbicularis oris muscle was observed. These experiments led to the conclusions as follows: 1) The muscle contractibility is kept within normal range if a half of the nerve fibers remain intact. 2) In the case of nerve crush, more than a half of total fibers regenerates and functions normally. Thus, the muscle function recovers completely. 3) In the case of nerve sectioning, more than a half of total fibers does not regenerat and the muscle function does not recover completely. In this case, paralysis never recovers compl-etely.

Facial nerve paralysis was produced by inoculating rabbits with herpes simplex virus. Inoculations were made through the stylomastoid foramen into the facial nerve canal, the subarachnoid space, and the common carotid artery. Subarachnoid and common carotid artery inoculation caused encephalomeningitis, but facial nerve paralysis failed to develop. Inoculation through the stylomastoid foramen produced facial nerve weakness on the third day and severe paralysis on the sixth day. No improvement was noticed after 223 days of follow-up. Regeneration was extremely poor and the nerve tissues were totally replaced by collagen fibers in some animals. Even if regeneration was present, markedly proliferated collagen fibers surrounded the regenerated nerve. In some cases, a typical labyrinthine disturbance resulted which could be ascribed to interneuron spread of the virus.