Subtonsillar placement of auditory brainstem implant.

A 26-year-old female with NF2 underwent removal of an acoustic schwannoma via extended retrosigmoid approach with subtonsillar placement of the auditory brainstem implant. The patient had already shown palsy of the lower cranial nerves on the opposite side due to previous surgery. Differing from conventional routes such as the translabyrinthine and the retrosigmoid, the subtonsillar approach enabled us to observe the entire cochlear nucleus and avoid injury to the 9th and 10th cranial nerves when applying the electrode. Hearing in pure tone average was maintained almost at the preoperative level. We present a new use of this approach in placing the electrode and discuss its advantages.

[Speech perception ability in a patient with a 8-channel auditory brainstem implant].

Auditory brainstem implant (ABI) is a central prosthesis that directly stimulates the cochlear nucleus in the brainstem for those who have interrupted auditory nerves and cannot benefit from the cochlear implantation. Speech perception in a recipient of the Nuclues 8 channel ABI, the first in Japan, is reported. A 25-year-old man with bilateral acoustic nerve tumors postlingually deafened due to tumor resection received auditory sensations with 5 channels. The correct answer using a coding strategy, SPEAK, was 35% for 5 vowels and 36% for 5 monosyllables. The use of ABI also improved his lip-reading ability on monosyllables and open-set words. This indicated that he benefited from ABI, although it was limited. Even after 1 year and 3 months of follow-up, he had no serious side effects such an infection or implant rejection.

Restoration of hearing with an auditory brainstem implant in a patient with neurofibromatosis type 2--case report.

A 25-year-old male with neurofibromatosis type 2 had hearing restored with an auditory brainstem implant (ABI) after removal of an acoustic schwannoma. The ABI allows the patient to discern many different environment sounds and is a significant adjunct to lip-reading, enabling conversation with people who have clear pronunciation without the necessity for writing.

[Significance of interferon alpha therapy for advanced renal cell carcinoma. Fukushima Renal Cancer Study Group].

We ranked prognostic factors to retrospectively evaluate the clinical significance of interferon alpha (IFN-alpha) therapy in patients with Robson stage IVB renal cell carcinoma. A total of 44 Robson stage IVB renal cancer patients were divided into 2 groups, one with more than 6 months administration of IFN-alpha (3-7 times a week: group A) and another without any IFN-alpha administration. The distribution of these 2 groups was not randomized. In addition to IFN-alpha therapy, survival was analyzed with respect to performance status (PS), mass reductive nephrectomy, concomitant use of other cytotoxic therapies, the number of metastatic organs, growth type, site of metastasis and the period of diagnosis, using a multivariate method with Cox proportional hazards regression. The multivariate analysis showed administration of IFN-alpha to be the most significant factor influencing a good prognosis. Improved survival was also significantly correlated with slow growing type and good PS. Among group A, a significant favorable prognosis was obtained in patients with the responses of no change (NC), partial response (PR) and complete remission (CR) 6 months after initiating administration of IFN-alpha, as well as with good PS and a slow growing type carcinoma. We conclude that IFN-alpha therapy might improve the prognosis of patients with Robson stage IVB renal cell carcinoma, especially, in cases when a greater than NC response is obtained after 6 months administration of IFN-alpha.

A rare case of acoustic neuroma extending from the cerebellopontine angle to the external auditory canal.

A 57-year-old woman presented with tinnitus and complete hearing loss in her right ear and a mild right-sided facial palsy. She was found to have an atypical acoustic neuroma involving the internal auditory canal, labyrinth, and middle ear, extending into both the cerebellopontine angle and the external auditory canal. The tumour was completely removed as a two-stage surgical procedure. The underlying mechanism for the atypical extension is discussed.

[Transurethral balloon laser thermotherapy for benign prostatic hyperplasia].

Between April 1994 and March 1995, transurethral balloon laser thermotherapy (TUBAL-T) using Prostalase was performed on 53 patients with benign prostatic hyperplasia. Clinical efficacy was evaluated at 3 months after TUBAL-T. The mean international prostate symptom score (I-PSS) decreased from 21.5 at baseline to 11.3 after 3 months (p < 0.0001). Irritative (the sum of items 1, 2, 4 and 7 of I-PSS) decreased by 55%, while obstructive symptoms (the sum of items 3, 5 and 6 of I-PSS) by 45%. However, other objective parameters such as maximum flow rate, voided volume, percent postvoid residual volume and prostate volume showed no significant change (7.8 to 7.2 ml/s, 130 to 147 ml, 33 to 28% and 39.7 to 41.0 ml, respectively). In conclusion, significant improvement after TUBAL-T was observed for subjective symptoms, especially irritative symptoms, but not for objective parameters.

[Sound lateralization testing based on interaural intensity difference discrimination and interaural time difference discrimination in acoustic neurinoma patients--comparison of ABRS].

Sound lateralization is considered useful in diagnosing retrocochlear lesions. Interaural time difference (ITD) discrimination has been considered more important than interaural intensity difference (IID) discrimination in diagnosing retrocochlear lesions. The purpose of this study was to determine whether testing sound lateralization by IID and ITD discrimination is useful in patients with acoustic neurinomas (AN). Twenty patients (15 to 74 years old) with unilateral AN were studied by testing IID and ITD discrimination using a self-recording device by delivering 500 Hz band noise through head-phones. Auditory brainstem response (ABR) testing and magnetic resonance imaging (MRI) were also performed in all patients. IID discrimination abnormalities were found in 25% of all patients, and ITD discrimination abnormalities in 85%. Five patients (25%) showed both IID and ITD discrimination abnormalities. One of the three patients with both normal IID and ITD discrimination showed waves I and V, and two of them showed waves I, III and V. One of the five patients with both IID and ITD discrimination abnormalities showed no response, two of them showed only wave I, the other two showed waves I, III and V. Two patients with latency prolongation between waves III and V had both IID and ITD discrimination abnormalities, and seven patients with latency prolongation between waves I and III had normal ITD discrimination or slightly abnormal ITD discrimination and normal IID discrimination. Three of the four patients with large tumors (> 3 cm) had both IID and ITD discrimination abnormalities, while two patients with small ear tumors (< 1 cm) had both normal IID discrimination and normal ITD discrimination. Normal ITD discrimination or slightly abnormal ITD discrimination was found in the majority of patients with wave III. Impairment of ITD discrimination was well correlated with wave III abnormalities. Patients with latency prolongation between waves III and V showed a high degree of ITD discrimination abnormality. Impairment of IID discrimination was related to a high degree of cochlear nerve damage or brainstem damage. We emphasize that IID discrimination is important in the neurological diagnosis of AN, in addition to ITD discrimination. Sound lateralization testing was a useful screening test for diagnosing AN, because tumor size influenced lateralization in every patient, and ITD discrimination was closely correlated with the ABR findings.

Aneurysm arising from the petrous portion of the internal carotid artery: case report.

A 21-year-old man with hearing loss and recurrent otorrhagia was shown angiographically to have an aneurysm arising from the intrapetrous internal carotid artery (ICA). Endovascular balloon occlusion of the aneurysm with preservation of the parent ICA was attempted twice, but each time the balloon deflated and the aneurysm reappeared two weeks and three months, respectively, following the endovascular procedures. The patient was then successfully treated with a surgical trapping procedure combined with superficial temporal artery-middle cerebral artery bypass.

[Image analysis of the inner ear with CT and MR imaging: pre-operative assessment for cochlear implant surgery].

Recent progress in magnetic resonance imaging (MRI) has made it possible to obtain detailed images of the inner ear by delineating the lymphatic fluid within the labyrinth. We analyzed CT scans and MR images in 70 ears manifesting profound deafness owing to inner ear lesions and compared their detective ability for inner ear lesions. The following results were obtained. 1) CT scan examination showed slight to extensive ossification of the labyrinth in six ears (9%), whereas MRI examination revealed low to absent signal intensity of the inner ear in nine ears (13%). Therefore, it was concluded that MRI is more sensitive in detecting abnormalities of the inner ear than CT scan. 2) MRI provided useful information as to whether the cochlear turn is filled with lymphatic fluid or obstructed. This point was one of the greatest advantages of MRI over CT scan. 3) Abnormal findings in either or both the CT scan and the MRI were detected in suppurative labyrinthitis occurring secondary to chronic otitis media, bacterial meningitis and in inner ear trauma. However, such abnormal findings were not detected in patients with idiopathic progressive sensorineural hearing loss, ototoxicity or sudden deafness. These findings should be taken into consideration in pre-operative assessment of cochlear implant candidates.

[Postoperative intravesical instillation of THP for superficial bladder tumor: clinical results of prophylactic effects on the recurrence. Fukushima THP Research Group].

Intravesical instillation of pirarubicin (THP) was performed on 66 patients with superficial bladder cancer after transurethral resection to evaluate the prophylactic effect against tumor recurrence. Intravesical chemotherapy was carried out at the concentration of 20mg/40ml. THP was initially instilled three times for one week, following instillation of every two weeks for ten times, and then every one month for seven times. Bladder irritability was demonstrated 21 of 66 cases (31.8%). Although there was a case of contracted bladder, generalized side effect was no case. Eligible cases for evaluation of efficacy were 43 out of 66 patients. The non-recurrence rate (by Kaplan-Meier's method) at one and two years were 90.4% and 77.8%, respectively. Intravesical THP instillation seems to be effective for the purpose of prophylaxis against the recurrence of superficial bladder tumor.

Factors contributing to phoneme recognition ability of users of the 22-channel cochlear implant system.

A study was carried out to determine which factors contributed to the vowel and consonant recognition ability of recipients of the 22-channel cochlear implant system. On the basis of the statistical analysis, no isolated factor showed a strong correlation with vowel recognition score. On the other hand, negative correlations were found between patients' consonant recognition scores and postoperative psychophysical percepts such as threshold levels and maximum comfortable loudness levels. However, multiple regression analysis also showed that the combination of lower threshold levels, a larger number of usable electrodes, and wider dynamic ranges contributed to higher consonant recognition scores.

[Effect of KT-611 (Naftopidil) on the contraction of human prostatic tissue and its use in benign prostatic obstruction].

A new alpha 1-adrenergic receptor antagonist, KT-611 (naftopidil) antagonized dose dependently the contraction induced by agonists, noradrenaline and phenylephrine in the human prostatic tissue. KT-611 at a dosage of once or twice a day was evaluated for its effects on 49 patients with benign prostatic hypertrophy. The drug improved subjective and objective symptoms significantly. The residual urine was reduced in volume and percentage significantly. The average and maximum flow rates increased significantly. The optimal dosage was presumed to be in the range of 25 to 75 mg once a day or 25 to 100 mg twice a day. Adverse reactions and abnormal laboratory findings were all slight. KT-611 was concluded to be useful in the treatment of patients with benign prostatic hypertrophy.

[Acoustic memory of the speech evoked by a 22-channel cochlear implant].

Immediate recall of serial 6 digits was examined in order to clarify whether the electrical information heard via a 22-channel cochlear implant can give rise to normal acoustic memory or not. Serial 6 digits were generated randomly using the digits 1 through 6. Following results were obtained in 2 patients with the implant prosthesis. 1) There was a normal primary effect, i.e., good performance of recall at the first or two digits, and also a normal recency effect, i.e., an increased probability of recall at the last one or two digits. 2) There was a normal suffix effect or attenuation of the recency effect when the digits were followed by an another irrelevant speech suffix, the "8". 3) The suffix effect, however, was not observed when the digits were followed by a non-speech noise suffix. Thus, in noise suffix mode, probability of recall was increased at the last one or two digits as similarly with in no suffix mode. The primary effect, the recency effect and the suffix effect are already regarded as the characteristic items of acoustic memory produced in subjects with normal hearing ability. Therefore, it was suggested that a speech perception with a 22-channel cochlear implant prosthesis can produce an normal acoustic memory, and that there is a similarity of neurophysiological functions between natural audition and electrical audition. Moreover, it was demonstrated that the patients with the cochlear implant can distinguish between speech and noise.

[Changes of the threshold level in patients with 22-channel cochlear implant].

Psychophysical responses of the patients to electrical stimulation were examined in order to clarify long-term effects of the cochlear implant in 9 patients who had received a 22-channel cochlear implant. Measured items were the minimal threshold level (T-level), the maximum comfortable level (C-level), and the dynamic range between T- and C-level. Measurements were repeated for each electrode every three months over more than 6 months. Following results were obtained. 1) The changes of the T-level were classified into four types as follows, a type with no change, a type with gradual decrease, a type with decrease in two to three months followed by gradual increasing threshold and a type with gradual increasing just after surgery. Even in a last type, the maximum increase in the T-level did not exceed 200 microA and, in most cases, these changes were stabilized within a few months after implantation. 2) The dynamic range gradually increased. It was obvious in both in the middle and apical electrodes, while such increased threshold was not observed in the basal electrodes. 3) In some cases, a few basal electrodes could not been used since they caused uncomfortable sensation or those dynamic ranges became below a certain extent. As a result, it was suggested that the electrical stimulation had not induced serious degeneration of the ganglion cells and the auditory nerve fibers. The reduction in the number of usable electrodes might be due to the surgical trauma to the intracochlear tissue. Therefore, exposing of the scala tympani should be minimal in order to avoid the damage of the cochlea.

[Diagnosis of conductive deafness by static compliance].

The diagnosis of the ossicular condition, fixation or interruption, is often not achieved by the tympanometry, because the overlap of the distribution of the static compliance (SC) is so great with the normal group in these two groups. Therefore, it has been said that SC, by itself, has little diagnostic value for differentiating the ossicular lesion. The overlap of the distribution of SC, however, was much smaller between the group with ossicular fixation and the one with ossicular discontinuity. So, apart from deviation from the normal range of SC, the limiting value of SC for discriminating the two groups was determined in ears with conductive hearing loss. The subjects were fifty-one ears with ossicular fixation and seventeen ears with ossicular discontinuity, in which ossicular lesions were surgically confirmed. All ears showed intact tympanic membrane. The limiting value of SC was 0.9 cc. The internal check using this discriminant value showed high ratio of discrimination, i.e. 94.1% in the fixation group and 64.7% in the discontinuity one were diagnosed correctly. Therefore the author proposed this value as the new criteria to differentiate type As ("s" mean sclerosis) tympanogram from type Ad ("d" means discontinuity) one. In addition, the comparison of SC with the normal side in twenty-five unilaterally affected ears showed smaller SC in 75% of the fixation group and larger SC in 92.3% of the discontinuity one than the normal side. Thus, it can be said that SC have useful value in separating ossicular fixation from ossicular discontinuity, if one compares ears with both the intact tympanic membrane and conductive hearing loss.

[Image analysis of the contour of paralyzed vocal cord during phonation].

The development of digital radiography (DR) has made it possible to analyze the contour of the laryngeal soft tissue structures in more detail than the conventional screen-film method. We analyzed the contour of the paralyzed vocal cord during phonation using motion subtraction technique. Forty four patients with unilateral recurrent nerve palsy were examined. The images were obtained by means of frontal tomography of the larynx during quiet inspiration and normal (expiratory) phonation. Tomography during inspiratory phonation was also examined in ten patients who can perform it. The thickness of the slices was 5.0 mm. The authors found that the free margin of the paralyzed vocal cord shifted by the aerodynamic power along the direction of the air flow, i.e. it shifted to the cranial direction during normal phonation and to the caudal during inspiratory phonation. The displacement phenomenon of the paralyzed vocal cord was significantly correlated with the degree of vocal cord atrophy (p less than 0.01). The result would indicate that the aerodynamic power during phonation is one of the factors eliciting the higher position of the paralyzed vocal cord during phonation, in addition to its anatomical displacement due to abduction of the paralyzed arytenoid. This notion should be taken into consideration in selecting the surgical approach for the treatment of unilateral recurrent nerve palsy.

High-resolution MR imaging of the inner ear.

The magnetic resonance (MR) images of the temporal bones have been analyzed, these MR images taken with head coils utilizing a 1.5-Tesla magnet whole-body imaging system. The MR images were acquired by means of spin-echo pulse sequences, and the thickness of the sections was 2.5 mm. By this modality, the T2-weighted images could clearly delineate the details of the liquid-containing labyrinthine structures and facial nerve. MR imaging can provide information that is unobtainable from a CT scan in the diagnosis of inner ear disorders, particularly as to whether the membranous labyrinth is filled with the lymph fluid or is fibrosed. This point is one of the greatest advantages of MR imaging over a high-resolution CT scan.

Tympanometry using a sweep-frequency probe tone and its clinical evaluation.

In this new tympanometric system, air pressure in the external meatus is kept constant at either -200 daPa or 0 daPa. The frequency of the probe tone is swept from 220 to 2,000 Hz (or 2,500 Hz, if necessary) in 4 s. During this frequency sweep, sound pressure in decibels and phase angle in degrees in the external meatus are sampled and the differences in sound pressure and phase angle measured at -200 and 0 daPa pressures are computed. These results are figured as a frequency-sound pressure curve and a frequency-phase angle curve. From the study on 8 fresh human cadaver temporal bones, four parameters in these curves are selected by discriminant analysis to provide diagnostic criteria: the minimum value and the 0-cross frequency of the frequency-sound pressure curve and the maximum value and its frequency of the frequency-phase angle curve. Normal parameters were determined in 50 normal ears. Evaluation of 40 patients with ossicular disorders revealed that 10 out of 12 cases of ossicular discontinuity and 5 out of 6 cases of malleus and/or incus fixation were correctly diagnosed. For stapes fixation, the diagnosis was correct in 12 out of 22 ears. This system is useful in the clinical diagnosis of ossicular disorders, producing a collection of curves and parameters that are distinctively different for the ossicular discontinuity and the ossicular fixation.