PubMed Health⌕ Search

Biomedical subjects

T O-Uchi

Publications and source records attributed to T O-Uchi.

At least 19 recordsLinked to original sources
PubMed1998

Age-related changes in transiently evoked otoacoustic emissions and distortion product otoacoustic emissions in normal-hearing ears.

Age-related changes in transiently evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) were evaluated in normal-hearing ears. The TEOAE was elicited by a non-linear click with a stimulus level of 82 +/- 1 dB SPL using ILO 88 in 251 normal-hearing ears. The DPOAE at the frequency of 2f1-f2 was measured with stimulus levels of 70 dB SPL (f1) and 60 dB SPL (f2) and with an f2/f1 ratio of 1.2 using ILO 92 in 64 normal-hearing ears. The results obtained showed that TEOAE and DPOAE were decreased with increasing age. Moreover, the same pattern of gradual decrease in TEOAE and in DPOAE suggests the possibility of the same generating mechanism associated with outer hair cells (OHCs).

Acoustic Stimulation↗
PubMed1997

Clinical application of transiently evoked otoacoustic emissions after glycerol administration for diagnosis of sensorineural hearing loss.

Pure-tone audiometry and transiently evoked otoacoustic emission (TEOAE) measurements were made before and after glycerol administration in the ears of sensorineural hearing loss with three different clinical entities, i.e. Meniere's disease, cochlear Meniere's disease and unilateral sensorineural hearing loss of unknown cause without hearing fluctuation (SNHLWF). TEOAE was evoked after glycerol administration in several ears of Meniere's disease and cochlear Meniere's disease, in which it was not evoked before glycerol administration. Especially in patients with cochlear Meniere's disease, TEOAE was altered without an accompanying significant change in mean hearing level. The change in TEOAE after glycerol administration indicates that the active motile property of outer hair cells may be affected by endolymphatic hydrops.

Adult↗
PubMed1994

Immunological findings of serological tests in steroid-responsive sensorineural hearing loss.

The following results were obtained after serological examination of 11 patients with steroid-responsive SNHL including a case with the aortitis syndrome (Takayasu disease) and sensorineural hearing loss, and 3 cases with positive syphilitic reaction. i) Abnormalities of serum immunoglobulins IgG or IgM level were found in 6 of 11 cases (54.5%), ii) Abnormalities in lymphocyte subsets were found in 7 of 14 cases (50.0%), iii) Immunologic abnormalities were thought to be present in patients with steroid-responsive SNHL and related diseases, but no findings specific to either group were observed.

Adult↗
PubMed1994

Age-related changes in evoked otoacoustic emission in normal-hearing ears.

The evoked otoacoustic emissions (e-OAEs) elicited by both tone-bursts and clicks were investigated in normal-hearing ears of three age groups: young age group (approximately 30 years), middle age group (31-50 years) and old age group (51 years approximately). The pseudothreshold of tone-burst e-OAE at stimulus frequencies between 500 Hz and 2 kHz was significantly elevated in the middle and old age groups compared with that in the young age group. When the relationship between averaged emission cochleograms drawn from the mean pseudothresholds of tone-burst e-OAEs at 6 stimulus frequencies between 500 Hz and 4 kHz and averaged pure-tone audiograms was analyzed, a clear difference was found among the three age groups in a frequency range between 500 Hz and 2 kHz. Total echo power, reproducibility, highest peak power and frequency area peak power up to 4 kHz in click e-OAE significantly decreased in the middle and old age groups compared with those in the young age group. These results indicate the possibility that the function of cochlear micromechanics deteriorates in all cochlear partitions with increasing age, even in normal-hearing ears.

Acoustic Stimulation↗
PubMed1994

Pathophysiology of hearing impairment in acoustic neuroma with profound deafness: analysis by evoked otoacoustic emission and promontory stimulation test.

Evoked otoacoustic emissions (e-OAEs) were examined and promontory stimulus test (PST) done prior to tumor removal in 15 cases of surgically proven unilateral acoustic neuroma (AN) with more than 80 dB in pure-tone hearing level. The e-OAEs were elicited by tone-bursts at 1 kHz and 2 kHz, and an interaural difference in pseudothreshold of more than 10 dB was defined as a significant impairment of the cochlear function. In PST, electrical stimulation was applied by a burst mode at 6 stimulus frequencies between 50 Hz and 1600 Hz. The number of stimulus frequencies with a positive response was defined as the PST score. The results obtained were as follows; i) Mean interaural difference in e-OAE pseudothreshold was 16.0 dB at 1 kHz and 8.0 dB at 2 kHz, ii) Positive PST was found in only 40% of the subjects and the mean PST score was 0.93, iii). When the pathophysiology of hearing impairment was inferred from the combination of the findings in e-OAEs and PST, it was found that 33.3% of the subjects had pure cochlear impairment, 13.3% pure retrocochlear impairment and 46.7% cochlear-retrocochlear impairment. It is concluded that analysis of both e-OAEs and PST could clarify the pathophysiology of hearing impairment in AN with profound deafness, which cannot be determined by conventional psychoacoustic tests.

Acoustic Stimulation↗
PubMed1993

Clinical analysis of steroid-responsive sensorineural hearing loss.

In order to clarify general clinical features, characteristics of hearing level fluctuation, and therapeutic strategy in steroid-responsive sensorineural hearing loss, we conducted clinical analysis in the cases which were registered based upon the diagnostic criteria proposed by Kanzaki in 1981. The results obtained were as follows: (1) Disregarding steroid-responsiveness, both ears were impaired in all cases. (2) Female predominance and middle aged onset were found. (3) The underlying immunological abnormality could exist even in the cases without systemic autoimmune disease. (4) The mean incidence in acute hearing change was about once a year in low-frequency area and once 2 years in mid- and high-frequency areas. (5) The mean value of maximum hearing level fluctuation during follow-up period was about 35 dB. (6) The final prognosis of hearing was relatively excellent. (7) By the supplemental administration of Sairei-to for more than 2 years, the maintenance dose of prednisolone was reduced in 80% of the subjects without any significant deterioration of hearing.

Adolescent↗
PubMed1991

Hearing preservation in acoustic neuroma surgery by the extended middle cranial fossa method.

The results of attempted hearing preservation were investigated in 160 cases of acoustic neuroma surgery carried out by a team of otologists and neurosurgeons at Keio University Hospital during a 14-year period from 1976 to 1989. Surgery was carried out by the middle cranial fossa (MCF) approach in the earlier cases and by the extended middle cranial fossa (EMCF) approach in the more recent cases. Measurable postoperative hearing was preserved in 20 of the 160 cases. Preoperatively, 22 cases had tumors of 20 mm or smaller in diameter, hearing levels (HL) of 50 dB or lower, and speech discrimination scores (SDS) of 50% or higher; 8 (36%) met these conditions postoperatively. Among those cases with hearing preserved postoperatively, hearing was unchanged from the preoperative level in 9 cases and changed in 11 cases. Total tumor removal was achieved in 19 cases. In one case, part of the tumor was left in order to preserve hearing, but MRI and CT have revealed no change in hearing or tumor enlargement to date, at 4 1/2 years after surgery. Hearing was preserved but progressively deteriorated postoperatively in one case in which the tumor was believed to have been totally removed but there was recurrence and in another case of total resection of neurofibromatosis II. Postoperatively, there were increased incidences of absence of the stapedius reflex, Type V by Békésy audiometry, and prolongation of the IT5, disappearance of Wave V, and no response in measurements of the ABR.

Adolescent↗
PubMed1991

Preoperative findings and hearing preservation in acoustic neuroma surgery.

For the purpose of clarifying whether or not the possibility of hearing preservation can be predicted preoperatively, we compared clinical characteristics and preoperative test results between hearing preserved and hearing unpreserved patients. Based on an analysis of this study, we conclude that duration of symptoms, ABR findings and caloric test results, in addition to hearing level, speech discrimination score and tumor size should be considered as prognostic signs of hearing preservation. Although all factors do not suggest a definite possibility of hearing preservation, candidates for hearing preservation surgery should be selected according to these prognostic factors.

Adult↗
PubMed1991

Preservation of facial nerve function in acoustic neuroma surgery by the extended middle cranial fossa approach.

The anatomical preservation rates of the facial nerve and postoperative facial nerve function were investigated in cases of initial operation for acoustic neuroma by the middle cranial fossa or extended middle cranial fossa approach. The cases were divided chronologically into three groups according to the date of surgery. The rate of anatomical preservation was 93% in the most recent period, compared to 82.4% for the entire series. This was attributable to higher preservation rates being achieved in cases with medium or large tumors with increased experience. Also regarding postoperative facial nerve function, the number of cases with no paralysis or only partial paralysis increased and the number of cases requiring sacrifice of the facial nerve decreased as experience was accumulated in the series. Even when the facial nerve was preserved anatomically, however, facial-hypoglossal anastomosis was carried out actively if facial nerve function did not recover satisfactorily one year after surgery. For this reason, as many as 33% of the patients underwent anastomosis. This high percentage, however, is attributable to anastomosis ultimately being carried out in 47.7% of the patients in the early period; 22.2% of the patients in the most recent period underwent anastomosis.

Adolescent↗
PubMed1991

Diagnostic procedure for acoustic neuroma.

The authors' diagnostic procedure for unilateral acoustic neuroma and the reasoning behind it are explained. The actual methods involved will change with advances in methodology. At the present time, however, pure tone audiometry and simple radiographic imaging of the internal auditory canal (transorbital and Stenvers View) are first carried out. Then, if the hearing level (average hearing at 4 kHz and 8 kHz) is 70 dB or lower, auditory brain stem response audiometry is carried out. If it is 71 dB or higher, the patient is examined by MRI or CT. Contrast-enhanced CT is carried out when MRI is not available. Air CT is not necessary if MRI is available, but, in cases where hearing preservation is indicated, it may provide valuable information for identifying the tumor site within the internal auditory canal.

Audiometry, Pure-Tone↗
PubMed1991

Audiological findings in acoustic neuroma.

Audiological examinations are vital in the diagnosis of acoustic neuroma. In interpreting their results, however, it is necessary to consider the patient's hearing level. The most sensitive audiological examination is auditory brain stem response (ABR) audiometry. Its most useful parameter is the IT5. A U-shaped audiometric configuration suggests AN, since it is seen in 10% of patients with small tumors. Psychological audiometric tests can be excluded from the battery of screening tests since they have low rates of positive diagnosis. The stapedius reflex (SR) test also has a low positive diagnostic rate in cases of small tumors. Even with the parameters of absence of reflex, elevated threshold, and decay combined, the overall SR test has a lower positive diagnostic rate than ABR audiometry. Nevertheless, the SR test can be employed as a screening device in cases in which the hearing level at 2 kHz and lower is 70 dB or lower, even if it is 71 dB or higher at 4 kHz and 8 kHz. At present, ABR audiometry is applicable in only about half of AN cases. Therefore, the need for early diagnosis must be further emphasized.

Audiometry↗
PubMed1991

Hypoglossal-facial nerve anastomosis. Clinical observation.

We have reviewed 35 cases of hypoglossal-facial nerve anastomosis performed during the past 15 years for irreversible peripheral facial paralysis caused by surgery for acoustic neuroma. Of 27 patients who were followed more than 1 year after anastomosis, recovery of serviceable facial function was obtained in 25 (92.6%). Neural deficits secondary to transection of the hypoglossal-facial nerve were minimal or acceptable in most cases. The overall results were better in patients who underwent this procedure within 3 months after surgery for acoustic neuroma as compared with those who did so after 1 year or more. The 2 patients who underwent intracranial facial nerve reconstruction during surgery for acoustic neuroma and showed poor facial recovery have presented a challenge to our strategy in the treatment of such patients.

Adolescent↗
PubMed1991

Intracranial reconstruction of the facial nerve. Clinical observation.

Nine cases of intracranial facial nerve reconstruction are reviewed in this paper. All patients underwent this procedure for severe injury or disruption of the facial nerve during surgery for acoustic neruroma through the modified extended middle cranial fossa approach (1). Satisfactory recovery of facial function was obtained in 4 patients. Three patients underwent hypoglossal-facial nerve anastomosis 1.3-1.5 years later for no or poor recovery of the facial function. One patient refused any further surgical treatment despite unsatisfactory recovery. The remaining 1 patient, during a telephone interview, stated that facial function had not returned at all 1 year and 5 months postoperatively. Although some degree of associated movement or mass movement was unavoidable, facial movement and mimetic facial expression were better in the patients with satisfactory recovery, as compared with those after hypoglossal-facial nerve anastomosis (2). Fibrin glue, which we used in the latest 3 cases instead of suture, seemed to possibly solve the technical difficulty in placing a suture. Facial function after intracranial reconstruction with fibrin glue was as good or better than that after repair by suturing.

Adult↗
PubMed1990

Steroid-responsive sensorineural hearing loss associated with aortitis syndrome.

Five cases of sensorineural hearing loss associated with aortitis syndrome are presented, and their clinical features are discussed in detail. All patients were middle-aged females. Pure-tone audiometry revealed a high-tone gradual-loss type of configuration, and the recruitment phenomenon was proved to be positive in most cases. The degree of hearing loss correlated well with the erythrocyte sedimentation rate. However, the most remarkable clinical feature was that the hearing loss showed steroid responsiveness in all cases. Based on these clinical features, it was suggested that the steroid-responsive sensorineural hearing loss associated with this syndrome might not be an incidental accompanying symptom but rather one of the local manifestations of the disease arising from similar mechanisms as the systemic inflammatory process. Associated conductive disturbance is also discussed.

Adult↗
PubMed1990

[Suppression of evoked otoacoustic emissions by contralateral noise exposure in humans].

The effects of contralateral noise exposure on evoked otoacoustic emission (e-OAE) were investigated in 10 normal hearing subjects and 3 cases with unilateral deafness. The e-OAE was recorded by ILO88 and weighting noise was given to the contralateral ear (impaired side in unilateral deafness cases). The air conducted noise exposure showed suppressive effect on e-OAE along with the increase of noise stimulus intensity in normal hearing subjects, but did not in unilateral deafness cases. The degree of suppression in e-OAE was most remarkable in highest peak power between 1 kHz and 2 kHz in FFT picture and the mean value of maximal suppression in 10 normal hearing subjects was 2.2 dB. The bone conducted noise exposure showed no effects on e-OAE in either normal hearing subjects or unilateral deafness cases. It was suggested that the contralateral noise exposure could suppress the function of cochlear micromechanics probably via crossed olivocochlear bundle.

Acoustic Impedance Tests↗
PubMed1988

Study of the so-called cochlear mechanical tinnitus.

Stimulated oto-acoustic emission (OAE) was investigated in 225 ears with normal hearing and c5 dip hearing loss. Continual OAE persisting longer than 6 ms against the sound stimulation of relatively low intensities was frequently found in ears affected by tinnitus but without hearing loss and in the tinnitus ears with c5 dip hearing loss. The results suggest that there is an abnormality of cochlear micromechanics in these ears which might be related to the 'cochlear mechanical tinnitus' described by Kemp & Wilson in 1981.

Acoustic Stimulation↗
PubMed1983

The progression of hearing loss in the early stages of sudden deafness.

The pathogenesis of sudden deafness is still not known. Therefore, to clarify its pathophysiology, it is important to know whether the progression of hearing loss occurs in the early stage of sudden deafness. The subjects were 11 patients with sudden deafness showing the progression of hearing loss by pure tone audiometry after the onset of the initial attack of hearing loss. The progression of hearing loss was mostly observed within 4-7 days after the onset of the initial attack. Average hearing loss in initial audiometry was severe and the recovery was poor in the majority of cases. An exploratory tympanotomy was performed in five cases and revealed one case of perilymphatic leak from the round window and another case of suspected round-window membrane rupture. As far as the causes of the progression of hearing loss in the early stage of sudden deafness are concerned, the following could be considered (1) aggravation of viral labyrinthitis, (2) aggravation of the vascular lesion of the inner ear, and (3) rupture of the membranous labyrinth of window(s).

Adolescent↗