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Middle ear implants (MEIs) such as the Vibrant Soundbridge (VSB) are attractive and alternative treatments for patients with conductive, sensorineural, and mixed hearing loss who do not benefit from, or who choose not to wear, conventional hearing aids (HAs). Recent studies suggest that MEIs can provide better improvements in functional gain, speech perception, and quality of life than HAs, although there are certain risks associated with the surgery which should be taken into consideration, including facial nerve or chorda tympanic nerve damage, dysfunctions of the middle and inner ears, and future device failure/explantation. In Japan, a multi-center clinical trial of VSB was conducted between 2011-2014. A round window vibroplasty via the transmastoid approach was adopted in the protocol. The bony lip overhanging the round window membrane (RWM) was extensively but very carefully drilled to introduce the Floating Mass Transducer (FMT). Perichondrium sheets were used to stabilize the FMT onto the RWM. According to the audiological criteria, the upper limit of bone conduction should be 45 dB, 50 dB, and 65 dB from 500 Hz to 4, 000 Hz. Twenty-five patients underwent the surgery so far at 13 different medical centers. The age at the surgery was between 26-79 years old, and there were 15 males and 10 females. The cause of conductive or mixed hearing loss was middle ear diseases in 23 cases and congenital aural atresia in two cases. The data concerning on the effectiveness and safety of VSB was collected before the surgery and 20 weeks after the surgery. Significant improvements of free-field Pure Tone Audiogram (PTA) from 250 Hz to 8, 000 Hz were confirmed (p < 0.001). Hearing gain up to 40 dB was achieved in the 1, 000 Hz to 4, 000 Hz range. No deterioration in either air conduction or bone conduction at PTA was noted at 20 weeks after the surgery. Monosyllable speech perception in both quiet and noisy conditions improved significantly (p < 0.001). The speech discrimination score in both quiet and noisy conditions improved significantly too (p < 0.001). In the future, it is likely that there will be an increasing population even in Japan that will meet the criteria for MEIs such as VSB. However, the long-term efficacy and safety of these devices should be established.

The Vibrant Soundbridge (VSB) is an active middle ear implant with the Floating Mass Transducer (FMT). We performed a multicenter study to study the efficacy of the VSB by means of "the 10 Questionnaire on Hearing 2002" and "the APHAB questionnaire" at 13 hospitals between 2011 and 2013. In all, 23 patients with mixed or conductive hearing loss received VSB implantation by the round window placement technique. These individuals were generally unable to use, or gained little from conventional hearing aids or bone conduction hearing aids. Two questionnaires were administrated before the surgery and 20 weeks after the VSB implantation. Scores on every item of "the 10 Questionnaire on Hearing 2002" showed significant improvement under noise after VSB implantation. On the APHAB, the scores for Ease of Communication, Reverberation, and Background subscales improved significantly after the VSB implantation, while the score for the Aversiveness subscale alone failed to show a positive improvement from the inexperience to the new sound. Analysis of the responses to these subjective questionnaires revealed better results after VSB implantation as compared to the preoperative data. In conclusion, RW vibroplasty with the use of VSB provided subjective benefit in patients with conductive and mixed hearing loss.

We retrospectively analyzed the clinicopathological factors affecting survival in patients with previously untreated parotid carcinoma. The subjects were 50 patients treated in our department from 1987 through 2011. The T stage was T1, T2, T3, and T4 in 4 patients, 11 patients, 9 patients, and 26 patients, respectively. The N stage was N0, N1, and N2 in 36 patients, 3 patients, and 11 patients, respectively. The clinical stage was I, II, III, and IV in 4 patients, 10 patients, 7 patients, and 29 patients, respectively. Histopathologically, eleven tumor types were observed; mucoepidermoid carcinoma was the most common. The overall 5-year survival rate was 72.1%, and the disease-specific 5-year survival rate was 74.0% in 42 patients who received radical surgery. Twelve patients relapsed; the site of relapse was the primary site alone in 2, in the neck alone in 3 patients, in the neck with distant metastases in 2 patients, and in distant metastatic site (s) alone in 5 patients. Univariate analysis showed that significant prognostic factors for overall survival rates were the T stage, cervical lymph node metastasis, clinical stage, grade, facial nerve palsy, and tumor size. We concluded that patients at high risk of recurrence should receive adjuvant therapy to improve the therapeutic outcomes.

The effectiveness of bone anchored hearing aid (BAHA) for the patients with congenital aural atresia was evaluated by multicenter clinical study in Japan. Twenty patients (17 bilateral and 3 hemilateral) of congenital auricular atresia were registered for this study and finally, 18 of them (15 bilateral and 3 unilateral) were subjected to further evaluation. Primary endpoint of this study was free sound-field pure-tone audiometory and speech threshold hearing test in quiet and noisy circumstances. Secondary endpoint of this study was patient's satisfaction based upon APHAB (Abbreviated Profile of Hearing Aid Benefit) questionnaire survey. These results were compared between before and 12 weeks after BAHA surgery. Both hearing level of pure tone and speech threshold significantly improved after BAHA surgery. APHAB scores also suggested the improvement of the QOL after BAHA usage, except for the scores that concerned with unpleasantness of noisy sound. BAHA is one of the useful options for the treatment of congenital auricular atresia.

Background: Because of the lack of reproducible brainstem ischemia models in rodents, the temporal profile of ischemic lesions in the brainstem after transient brainstem ischemia has not been evaluated intensively. Previously, we produced a reproducible brainstem ischemia model of Mongolian gerbils. Here, we showed the temporal profile of ischemic lesions after transient brainstem ischemia., Results: Brainstem ischemia was produced by occlusion of the bilateral vertebral arteries just before their entry into the transverse foramina of the cervical vertebrae of Mongolian gerbils. Animals were subjected to brainstem ischemia for 15 min, and then reperfused for 0 d (just after ischemia), 1 d, 3 d and 7 d (n = 4 in each group). Sham-operated animals (n = 4) were used as control. After deep anesthesia, the gerbils were perfused with fixative for immunohistochemical investigation. Ischemic lesions were detected by immunostaining for microtubule-associated protein 2 (MAP2). Just after 15-min brainstem ischemia, ischemic lesions were detected in the lateral vestibular nucleus and the ventral part of the spinal trigeminal nucleus, and these ischemic lesions disappeared one day after reperfusion in all animals examined. However, 3 days and 7 days after reperfusion, ischemic lesions appeared again and clusters of ionized calcium-binding adapter molecule-1(IBA-1)-positive cells were detected in the same areas in all animals., Conclusion: These results suggest that delayed neuronal cell death took place in the brainstem after transient brainstem ischemia in gerbils.

Acoustic overstimulation is one of the major causes of hearing loss. Glutamate is the most likely candidate neurotransmitter for afferent synapses in the peripheral auditory system, so it was proposed that glutamate excitotoxicity may be involved in noise trauma. However, there has been no direct evidence that noise trauma is caused by excessive release of glutamate from the inner hair cells (IHCs) during sound exposure because studies have been hampered by powerful glutamate uptake systems in the cochlea. GLAST is a glutamate transporter highly expressed in the cochlea. Here we show that after acoustic overstimulation, GLAST-deficient mice show increased accumulation of glutamate in perilymphs, resulting in exacerbation of hearing loss. These results suggest that GLAST plays an important role in keeping the concentration of glutamate in the perilymph at a nontoxic level during acoustic overstimulation. These findings also provide further support for the hypothesis that IHCs use glutamate as a neurotransmitter.

Many current studies have suggested that herpes simplex virus is a probable cause of Bell's palsy, and that treatment with antiviral agents such as acyclovir might benefit the patients. In the present study, 69 patients with Bell's palsy were treated with oral administration of acyclovir (2000 mg/day) and prednisolone (60-40 mg/day) at Ehime University Hospital between Oct. 1995 and Dec. 1998. Patients enrolled in this study met the following criteria: 1) severe or complete paralysis with a score lower than 20 by the 40-point Japanese grading system, and 2) treatment started within 7 days of onset. The overall recovery rate was 95.7% (66/69). The rate in patients who started this treatment within 3 days after disease onset was 100%, and this early treatment was highly efficacious in the prevention of nerve degeneration and resulted in a significantly better recovery. By comparison, the recovery rate in patients whose treatment was started 4 days or more after onset was only 84.2%. All patients who were given a diagnosis of zoster sine herpete and treated with acyclovir-prednisolone had a good outcome. These results suggest that early treatment, within 3 days after palsy onset, is necessary for effective acyclovir-prednisolone therapy of Bell's palsy.

Results of surgery for middle ear cholesteatoma were investigated in 202 ears of 197 patients who had undergone surgery by the staged intact canal wall technique. Surgical procedures used in the second stage for prevention of a retraction pocket were classified into three types: Type S1, no scutumplasty; Type S2, scutumplasty; Type S3, scutumplasty plus mastoid obliteration. Recurrent cholesteatoma was found in 9 ears (4%) and retraction pocket in 47 ears (23%). They occurred between 2 and 120 months (average: 26 months) after the second stage, most frequently at 1 to 3 years. The incidence was higher after Type S3 surgery than after the other types, probably because the middle ear was severely involved in patients who were indicated Type S3 surgery. For prevention of a retraction pocket, bone putty and cartilage were proved to be appropriate materials for scutumplasty, and hydroxyapatite for mastoid obliteration. As the retraction pocket tended to recur in patients with the pocket at the second stage, these patients needed obliteration of the mastoid cavity to prevent a retraction pocket. Postoperative hearing was evaluated according to the criteria proposed by the Japan Society of Clinical Otology. Of 145 ears of the 142 patients who were followed for more than 1 year, 118 ears (81%) the surgery was judged successful. The success rate in hearing was in good accordance with the condition of the tympanic membrane.

Blood patch is a therapeutic procedure that uses a perilymphatic fistula to repair an inner ear window rupture by filling the tympanic cavity with autologous blood. The experimental study was conducted in 13 guinea pigs. Autologous blood or commercially available fibrin glue was poured into the otic bulla after artificial rupture of the round window. The animals were sacrificed immediately, or 1 to 7 days after the operation. The results showed that the blood or the fibrin glue successfully closed the window rupture by closing directly and by facilitating the formation of granulation at the margin of the rupture. Fibrin glue seemed to be preferable to autologous blood due to its non-toxic nature in the inner ear.

The incidence and prognosis of bone defects occurring in the mastoid cavity were investigated in 205 ears of 197 patients who underwent planned two-stage tympanoplasty by the intact canal wall technique. Bone defects found at the first stage had spontaneously closed by the second stage in 43 of 62 ears at the mastoid tegmen, in 13 of 15 ears at the posterior wall of the mastoid cavity and in 2 of 17 ears at the posterior wall of the external ear canal. Twenty two ears developed bone defects at the ear canal between the first and second operations, despite the canal wall having been primarily preserved. Of the 6 ears with closure of the labyrinthine fistula using temporalis fascia at the first stage, the defects were obliterated with regenerated bone in 5 ears at the second stage. Bone defects at the facial canal were recognized in 67 ears at the first stage, 21 of which were no longer seen at the second stage.

Surgical treatment of petrous cholesteatoma that involves the petrous pyramid and extends beyond the internal auditory canal is often difficult because of the site and extent of the cholesteatoma. Various problems pertaining to the operation are discussed from our experience with fourteen patients who underwent surgery in our hospital. When accompanied with otorrhea, the middle ear was eradicated by radical mastoidectomy before total removal of the cholesteatoma in order to avoid intracranial infection. Staging operation was conducted in 6 patients in which otorrhea could not be stopped by conservative treatment. The surgical approach was translabyrinthine in 10 patients, middle cranial fossa plus transmastoid in 2, and a combination of these methods in 2. The postoperative large cavity was totally exteriorized in 5 cases in which eradication of the cholesteatoma was deemed too risky, although the exposed internal auditory canal and the denuded dura were supplemented locally. In the other 9 cases, the cavity was obliterated with abdominal fat and/or muscle flap. Facial nerve palsy was present preoperatively in 11 patients. They were treated by decompression in 7 cases, nerve-anastomosis in 2 and nerve grafting in one. In one patient, atrophy of the nerve was too severe to perform nerve grafting. Plastic surgery, such as suspension of the eyelid and masseter muscle transfer, was additionally carried out in 6 of the above patients. Postoperative follow-up study with CT and MRI is very important. In 3 of our cases, the cholesteatoma recurred and the reoperation was needed.

Between June 1990 and May 1993, 17 acoustic tumors were removed by the middle cranial fossa approach with attempted hearing preservation. Measurable hearing was restored in 13 patients (76.5%) and useful hearing (PTA < 50 dB, SDS > 50%) in 10 patients (58.8%). In addition, significant hearing improvement, greater than 10 dB in pure-tone average, was noted in 6 patients (35.3%). In the hearing improvement group, useful hearing was restored after tumor resection in two patients with poor preoperative hearing. These six patients with hearing improvement exhibited several findings in common: smaller tumors, sudden deterioration of hearing, trough type of audiogram, inferior vestubular nerve origin and short duration of hearing loss before surgery. Such signs suggested favorable preoperative prognostic factors for potential postoperative hearing improvement. Because there was no significant difference between postoperative facial nerve outcome in the middle cranial fossa approach and the translabyrinithine approach in our series of small tumors, we recommend the use of the middle cranial fossa approach for hearing preservation in patients with small tumors, even when their hearing is poor preoperatively.

The patient was a 41-year-old man who lost his hearing on the left at 7 years of age and on the right at 34 years of age due to meningitis. At 35 years of age a single-channel cochlear implant, 3M/House design, was implanted. Five years after the initial operation, the single-channel prosthesis was replaced by a multichannel device (Cochlear Corp.) because of the patients earnest wish to obtain better hearing. Explanation of the short electrode of the single-channel device was easy, but reimplantation of the longer electrode of multichannel device was somewhat difficult, probably because of the presence of the peri-implant fibro-osseous cuff in the Scala tympani. Single-channel and those of the multichannel speech data were compared in relation to performance in the same individual. The reimplanted multichannel device was equivalent to or outperformed the original 3M prosthesis. The patient preferred the hearing afforded by the multichannel device.

Although radiotherapy has been generally accepted as the treatment of choice for nasopharyngeal carcinoma (NPC), NPC at the primary site is not always controlled by this therapy. We performed surgical treatment to eradicate such residual tumor through a transmandibular, transpterygoid approach, on four patients with local residual NPC after curative radiotherapy. Two patients survived with no evidence of disease for more than 6 years. The other two patients died of multiple metastases to the liver or bone at 4 years and at 6 months after treatment. However, the nasopharynx remained free of disease in these two patients. Although the number of patients in the present series is small, surgical treatment of local persistent tumor after radiotherapy was beneficial. The indication for this technique is tumor in the nasopharynx extending to the parapharyngeal space, not invading intracranially. The transmandibular, transpterygoid approach offers a wide operative field with minimal postoperative morbidity, making it possible to manage the internal carotid artery easily.

Cochlear input impedance was measured in 6 temporal bones taken from 3 dogs by use of a newly developed ceramic device. The device was composed of two ceramic bimorph elements, one for activation of the stapes and the other to pick-up vibration of the former element in the form of an electric output, which varies in accordance with the magnitude of cochlear impedance. Average impedance in the dogs was 2.3 Mohm at 2 kHz, 6.3 Mohm at 4 kHz and 17.8 Mohm at 6 kHz. Effect of closure of the round window was also investigated by placing dental cement on the window. In 3 ears, the impedance increased mainly below 4 kHz, while in the remaining 3 ears no such change occurred. This was probably because the closure was complete in the former but not in the latter.

A variety of solutions were tested in vitro to find a suitable solvent of cholesteatoma debris for use in clinical practice. The specimens were taken during surgery from the patients of otitis media with cholesteatoma. They were divided in pieces and put in test tubes. Each tube was then admixed with one of the test solutions and incubated at 37 degrees C for 48 hours. Hydrochloric acid (1N) and sodium hydroxide (1N) had no substantial effect to solve the debris. Urea (10N), acetylcysteine (20%) and chymotrypsin (1%) had a weak such effect. Proteolytic agents such as diiodosalitylic acid (0.1N), sodium dodecyl sulfate (0.1N) and cholic acid (0.1N) showed a stronger effect but not enough for clinical use. In contrast, a detergent which contains interfacial active agents and a proteolytic enzyme (alkaline cellulase), such as Attack and Hi-Top, proved to be more effective to solve the debris. However, biological effect of such detergent on the ear is not clear. Further study will be necessary before actual application in the patients.

Recurrence of the perilymphatic fistula is not rare and may be a tough problem for surgical treatment. This is because a graft is usually applied on the ruptured window(s) from the middle ear and therefore the perilymphatic pressure directly acts on the graft. The recurrence may be caused by a technical failure, use of an unsuitable graft material, poor postoperative bedrest, trauma, increased inner ear pressure, etc. In our clinic, the recurrence occurred in 7 of 48 cases surgically treated. Vertigo accompanied with spontaneous or positional nystagmus was seen in all 7 recurrent cases, while only 2 of them complained of worsening of the existing hearing loss. Re-operation was carried out in two patients. In the first case, closure of the round window by the previous operation was found incomplete, and the perilymph leaked through the gap around the graft. In the second case, closure of the round window was complete, but perilymph leaked from the oval window. In order to prevent the recurrence, the operation should be carefully performed by using strong and adhesive tissue as a graft material, applying a glue between the graft and the inner ear window(s), and keeping strict postoperative bedrest.

Speech discrimination scores under noise circumstances were studied by use of the middle ear implant (MEI) and the conventional hearing aid (HA, HA-33, RION, Co, Ltd). The studies were performed in 10 patients implanted with the MEI and in 12 adult volunteers with normal hearing as a control. The tests were carried out using Japanese monosyllabic lists from 57S-speech discrimination test list as a test sound and multi-talker noise as a noise source. A speaker was placed in front of a subject in one meter apart. Sound characteristics of HA were adjusted as far as possible to those of the MEI by use of a sound equalizer. The intensity of speech sound pressure was adjusted at 65dB SPL, while that of the noise was changed to 65, 70 and 75dB SPL in the position of patients. Audiological evaluation of the MEI, the HA and control obtained by percentages of correct answers to 50 words in speech discrimination test with and without noise (65, 70, 75dB SPL). When the test was performed without noise, speech discrimination scores by the MEI and the HA were either 96.8 +/- 3.6% and 94.8 +/- 4.1%. However, under noise circumstances (65dB SPL) that by both devices were either 81.6 +/- 9.1% and 66.8 +/- 10.6% (P less than 0.001). When the intensity of the noise increased to 70 and 75dB SPL, speech discrimination scores by both devices deprecated together with consistent difference (P less than 0.01). Moreover speech discrimination scores by the MEI were almost same as control.(ABSTRACT TRUNCATED AT 250 WORDS)

Temporal auditory acuities provided by the middle ear implant (MEI) and by the hearing aid (HA) were compared in ten patients implanted with the MEI. Test sounds used in the experiment were tone bursts [rise and fall time: 25 msec, duration (t): 982-1000 msec, interval (T): 1000 msec] of 500 Hz or 2000 Hz at 70 dBSPL. A speaker was placed in front of a subject one meter apart. At first, the subject adjusted the gain control of outer unit at the most comfortable loudness level. He heard totally fifty times of the test sounds, which varied in duration each 2 msec difference between 982 and 1000 msec and were provided in random manner. Therefore, sound of each duration was given 5 times. The notch [= (T-t) x 2] of the test sounds recognized by the patients was regarded as time gap. Fifty percent discrimination thresholds, which were indicated by the gap times of the test sounds half identified, were obtained as the index of the temporal auditory acuity. Following the above test, performance of the HA was investigated by use of the same procedure. The results indicated that the temporal auditory acuities of the MEI were superior to those of the HA at 500 Hz (P less than 0.01) and 2000 Hz (P less than 0.001). When the intensity of the test sound at 2000 Hz decreased from 70 dBSPL to 60 or 50 dBSPL, the temporal auditory acuities of the MEI and the HA were almost depreciated together with consistent difference in the test of 6 patients (P less than 0.01, 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Single channel cochlear implant of 3M/House design was implanted to the three patients with profound hearing loss. Before the implantation, use of hearing aid had not afforded serviceable hearing enough for speech recognition in these patients. Postoperative courses were uneventful. Speech rehabilitation was started at 3 weeks after the surgery. The speech tracking scores with the cochlear implant plus lipreading achieved 20-25 bunsetues (the minimum meaningful unit of the Japanese sentence) per minute at three or four months after the operation. All the patients could recognize speech of daily life with help of lipreading. However, speech recognition by the cochlear implant alone was not satisfactory.

Speech perception by single channel cochlear implant can be improved to some extent by modifying the encoding process of the speech signals. The principle of our encoding strategy is to present speech signals with appropriate delay time for lower frequency components of the speech sound, while without delay for higher frequency components. This is based on a cochlear physiology that higher frequency sounds are perceived earlier than lower frequency sounds, since the former is perceived at the basal turn and the latter at the apical turn. The following tests were performed without the aid of lip reading in the two patients implanted with a single channel cochlear implant of 3M-House design. Lower frequency components of the speech signals were digitally delayed with a Sony SDP-777 ES surround processor. The results indicated that the optimal delay time for identification of /i/, /e/ and /u/ needed longer delay time, while that of /a/ and /o/ need shorter delay time, corresponding to the difference between the first and second formant of each vowel. Comparison of vowel perception with and without delay coding showed that vowel identification with delay coding was superior to that without it; 30% vs. 16% in case 1, and 48% vs. 30% in case 2.

One hundreds and forty-nine patients (221 ears) suffering from tinnitus were treated by an intravenous administration of Xylocaine. Xylocaine, 1mg per kg, was administered once a week. The immediate effect of Xylocaine on tinnitus was evaluated subjectively for all the patients. The long term effect in 57 patients who received Xylocaine administration more than 12 times was also analyzed. The results can be summarized as follows. 1. Short and long term relief of tinnitus was obtained in 165 of 221 ears (74.7%) and in 35 of 57 cases (61.4%), respectively. 2. This therapy was more effective in old patients and in the patients with low pitch tinnitus, or with positive residual inhibition. 3. The numbers of the effective cases increased after the 8th time administration of Xylocaine. Thus we recommend the Xylocaine administration at least 8 times. 4. The results of the loudness balance test were not correlated with the change of the subjective improvements. 5. The suppressive effect of tinnitus by injecting saline solution intravenously was recognized in 24 of 73 cases. At present, repeated administration of Xylocaine would be one of the most significant therapies of tinnitus.

The study by Brenkman et al. [J. Acoust. Soc. Am. 82, 1646-1654 (1987)] of malleus umbo and anterior crus of stapes displacement in 14 human temporal bones shows a mean -7.3-dB/oct slope above 1.0 kHz for stapes displacement in response to a 80-dB SPL input at the eardrum. The slope they obtained for midfrequency (1.0-4.0 kHz) stapes displacement is significantly flatter than what was found previously [Gyo et al., Acta Otolaryngol. 103, 87-95 (1987); Gundersen, Prostheses in the Ossicular Chain (University Park, Baltimore, MD, 1971); Kringlebotn and Gundersen, J. Acoust. Soc. Am. 77, 159-164 (1985); Vlaming and Feenstra, Clin. Otolaryngol. 11, 353-363 (1986a)]; in these studies, stapes displacement rolled off at -12.0 to -14.9 dB/oct above 1.0 kHz. It appears that their mean midfrequency stapes displacement slope has been flattened by some unusual results in a small number of ears. Possible reasons for these results are discussed.