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Biomedical subjects

Y Ushisako

Publications and source records attributed to Y Ushisako.

14 recordsLinked to original sources
PubMed1998

Cochlear implantation in a patient with profound hearing loss with the A1555G mitochondrial mutation.

OBJECTIVE: This study aimed to describe the performance of a cochlear implant in a patient with profound hearing loss with the A1555G mitochondrial mutation. SETTING: The study was conducted at two university hospitals. PATIENT: A 50-year-old Japanese man in whom bilateral profound hearing loss developed after administration of streptomycin at the age of 23 participated. The pedigree of the family showed exclusively maternal transmission of hearing impairment. INTERVENTION: Genetic study and auditory rehabilitation with a cochlear implant were performed. RESULTS: The A1555G point mutation was identified from the patient's mitochondrial DNA. Since activation of the implant, the patient has been using it successfully with a monosyllable recognition score of 78% using Japanese word lists for speech audiometry. CONCLUSIONS: The current case indicated that cochlear implantation may be a valuable choice of therapy for the patient with profound hearing loss with the A1555G mutation. The excellent auditory performance with a cochlear implant suggests that hearing loss associated with this mutation is primarily caused by insult to the cochlear tissue containing rich mitochondria (i.e., hair cells or stria vascularis or both), not to the cochlear nerve and its central connections.

Antibiotics, Antitubercular↗
PubMed1996

Cochlear implantation in an intralabyrinthine acoustic neuroma patient after resection of an intracanalicular tumour.

This case study describes a therapeutic strategy using a cochlear implant for a bilateral acoustic neuroma deafened patient. The cochlear nerve had previously been sacrificed on one side during tumour removal, but on the remaining side a functioning cochlear nerve was assessed by electric promontory stimulation in spite of a neuroma extending into the vestibular labyrinth. The patient was successfully stimulated with a Nucleus 22-channel implant after removal of the intracanalicular portion of the neuroma via a middle fossa approach.

Cochlear Implants↗
PubMed1996

[Tympanic electrocochleography with disposable electrode].

Extratympanic recording of electrocochleography (ECochG) has played an important role in the differential diagnosis of inner ear diseases. We used a special electrode, which was wrapped in a cotton ball at the tip and covered with a silicon sheath over the entire length, and recorded ECochG from the tympanic membrane (tympanic ECochG). Our method was found to be more convenient and less traumatic than recording with an ear canal electrode. Tympanic ECochG records from 10 normal volunteers showed no influence of iontophoretic anesthesia on the tympanic membrane. The effects on the conductive hearing mechanism were negligible. The input-output curve of the action potential (AP) by click stimuli was fairly stable and comparable to that obtained with transtympanic recording. We performed tympanic ECochG in patients with Meniere's disease or other sensory hearing loss, and compared the amplitude ratios of the summating potential (SP) and AP (SP/AP ratio) with those in normal hearing subjects. The SP/AP ratios in patients with Meniere's disease were significantly increased, an observation consistent with the results of other studies. The SP/AP ratio was also elevated in patients with autoimmune sensory hearing loss or perilymphatic fistula. Based on the results of the present study, we speculate that it is possible to diagnose an inner ear disorder by comparing the tympanic ECochG findings with not only records from normal subjects, but also the contralateral record of tympanic ECochG from the same subject. We conclude that tympanic ECochG using disposable electrodes can provide useful information on inner ear function, because of its convenience, non invasiveness and safety in clinical use. We found tympanic ECochG to be useful in the glycerol dehydration test and for monitoring inner ear function during acoustic neurinoma surgery.

Acoustic Stimulation↗
PubMed1995

[Hearing results after anterior tympanotomy in cholesteatoma surgery].

Between 1987 and 1993, 71 ears of attic type cholesteatoma and 20 ears of adhesive type were operated on using the intact canal wall technique combined with anterior tympanotomy. Pre- and postoperative pure tone hearing after the surgery were analyzed, especially to determine whether anterior tympanotomy is harmful to the inner ear. Mean values of 500, 1000 and 2000Hz of air conduction threshold immediately, before and about 1 year after the operation were compared. In attic cholesteatoma, type 1, type 3, and type 4 of ossiculoplasty revealed significant improvement of 8.4dB, 9.3dB, and 8.0dB respectively. In adhesive cholesteatoma, results obtained were 8.4dB, 0.8dB, and -3.0dB. Differences between pre- and postoperative bone conduction threshold at 4000Hz were 1.5dB in type 1, 1.3dB in type 3, and 5.0dB in type 4 in attic cholesteatoma. Those in adhesive cholesteatoma were -2.5dB, -0.2dB, and -10.0dB respectively. From the results obtained, we concluded that (1) our results were satisfactory with regards to hearing ability following all types of ossiculoplasty in attic cholesteatoma and in type 1 in adhesive cholesteatoma, (2) anterior tympanotomy itself is not a harmful procedure to the inner ear in both types of cholesteatoma, (3) an increase in bone threshold in adhesive cholesteatoma is due to the surgical procedure at the stapes and/or the oval window.

Adolescent↗
PubMed1995

Improvement of the surgical technique of anterior tympanoplasty in cholesteatoma.

Technical improvements in anterior tympanotomy with a transmastoid approach in cholesteatoma surgery are reported. Mastoidectomy must be extended to the root of the zygoma and the space anterior to the malleus head must be opened. For this purpose, the visual axis must coincide with the external meatal axis. In this head position, complete removal of the anterior attic bony plate becomes possible only through the transmastoid approach, without touching the ossicular chain. In the case of the pyramidal type bony plate with a normal ossicular chain, the incudo-malleal joint is temporary subluxated, as this is more convenient for access and removal of pathology than incudostapedial joint subluxation. Our clinical results on postoperative hearing showed no damage to the inner ear by the improved technique.

Cholesteatoma, Middle Ear↗
PubMed1994

Magnetic resonance imaging in patients with sudden deafness.

Although many theories on the etiology of sudden deafness have been proposed, the main pathological focus remains uncertain. In this study, MR examinations were performed on patients with unilateral sudden deafness to study the relationship between MRI findings and response to treatments, i.e. amidotrizoate, steroid, or both. In 7 out of 30 cases, the cochlea and/or the vestibule showed higher signal intensity on proton density and T2-weighted images on the diseased side (MRI positive cases). These findings suggest changes in the chemical composition of the perilymph and/or the endolymph, since proton density and T2-weighted images reflect water content. It appears that MRI positive sudden deafness is more difficult to cure even with the use of amidotrizoate or steroid than MRI negative sudden deafness. Amidotrizoate seems to be more effective in MRI negative sudden deafness. MRI would help us to further classify the etiology of sudden deafness.

Adolescent↗
PubMed1988

The significance of stapedial reflex test in facial nerve paralysis.

The stapedial reflex of 30 patients with peripheral facial nerve paralysis was compared with the results of facial paralysis scores. The stapedial reflex was measured with an oto-reflex analyser, RS-06A. The stimulation frequencies in the stapedial reflex test were 500, 1,000 and 2,000 Hz for both ipsilateral and contralateral stimulation. The stapedial reflex test at 500 Hz for contralateral stimulation seemed to be useful for evaluating the degree of facial paralysis. With 500 Hz or 1,000 Hz contralateral stimulation, the stapedial reflex test seemed to be useful for predicting the prognosis for facial nerve paralysis. In these stimulations, cases with a positive reflex within 2 weeks showed complete recovery within 12 weeks, and cases with positive reflex within 4 weeks showed recovery within 24 weeks.

Adolescent↗
PubMed1988

Studies on amidotrizoate therapy in sudden deafness (1978-1987).

The therapeutic effects of amidotrizoate in 47 sudden deafness patients from 1978 to 1987 were studied. The therapeutic results were investigated in terms of each of four variables: time from onset, degree of hearing loss, type of audiogram, and vertigo. Results showed that patients who had no vertigo, and were treated within 1 week of onset had satisfactory results. The degree of hearing loss did not influence recovery, although, all those with total loss type according to audiogram remained unchanged. Twenty-four of 34 cases (71%) treated within 2 weeks showed either complete or marked recovery; this proportion was not much different from the results in our previous investigations.

Adolescent↗
PubMedDate not supplied

A new test of Eustachian tube function with otoadmittance meter: tubotympanometry.

A new method for testing Eustachian tube function using an otoadmittance meter (Tubotympanometry) is reported. The otoadmittance meter is set for the aural reflex test, namely in the position of Y-T- recording. The patient is asked to carry out deep breathing. Valsalva's maneuvre, normal breathing, and swallowing in succession. In normal 40 ears, three types of the tubotympanogram were classified. In type A, observed in 32 ears, the graph shows no changes during deep breathing, a sudden downward deflection with Valsalva's maneuvre, a return to a level after the maneuvre and on repeated swallowing the graph returns to the initial level in stepwise. In type B, observed in 5 ears, the graph returns to the initial level directly after Valsalva's maneuvre without swallowing. This indicates a slightly patent tube, even though in the normal range. Type C was observed in 3 ears of patients who failed to perform Valsalva's maneuvre correctly. In the case of a patent tube, the graph shows a remarkable fluctuation synchronizing with inspiration and expiration. In the case of an occluded tube, the graph shows slower recovery after Valsalva's maneuvre and no complete return to the initial level even after repeated swallowing. In another case of occluded tube, the graph was deflected upward by Valsalva's maneuvre and showed no change on deglutition. The greatest advantage of this test is the simplicity of the equipment and of the test procedure.

Acoustic Impedance Tests↗