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Biomedical subjects

R T Miyamoto

Publications and source records attributed to R T Miyamoto.

At least 19 recordsLinked to original sources
PubMed1992

Longitudinal evaluation of communication skills of children with single- or multichannel cochlear implants.

Performance on speech perception, speech production, and language tests was measured over time in children who used the 3M/House or the Nucleus cochlear implant. The speech perception and production results demonstrated higher performance levels and faster rates of learning for the multichannel than for the single-channel users. The performance of the children with the single-channel implant on the speech perception and production measures reached a plateau by 1.5 years post implant, whereas the children using the multichannel device continued to show improvement after 2 or more years of implant use. Changes in language were limited over time with no obvious difference in performance as a function of type of implant.

Acoustic Stimulation↗
PubMed1991

Independent evaluation of the speech perception abilities of children with the Nucleus 22-channel cochlear implant system.

The performance of 28 children with the Nucleus multi-channel cochlear implant, who had used the device an average of 1.7 yr, was examined on a battery of speech perception measures. All children demonstrated better speech perception skills with the implant than they had in the preimplant condition with hearing aids. With the Nucleus implant, 61% of the children demonstrated some open-set speech recognition and another 14% demonstrated closed-set speech recognition. Scores on the tests were corrected for guessing and a hierarchy of test difficulty was developed. The results revealed systematic differences in performance as a function of perception task and test format. The results of regression analyses, which were performed to identify predictors of success, showed that communication mode made a significant unique contribution to the variance in performance among subjects on an open-set word recognition test. When the scores of the children who used oral or total communication were compared on the full battery of tests, however, there were few significant group differences.

Adolescent↗
PubMed1991

Contemporary management of neurofibromatosis.

The neurofibromatoses are two distinct entities with different genetic origins. The phenotypic expressions and required treatments are different. The devastating nature of neurofibromatosis-2 may be more effectively controlled through the application of advanced imaging techniques and contemporary neurotologic procedures. The most common manifestation of neurofibromatosis-2 is that of bilateral acoustic neuromas. The eventual total bilateral sensorineural deafness associated with this condition can be obviated in selected cases if the diagnosis is established early. Follow-up data are reported for three patients in whom hearing was preserved in at least one ear. When removal with hearing preservation is not possible, subtotal tumor removal with decompression of the internal auditory canals may delay progression of hearing loss. A new approach to tumors of the pterygomaxillary fossa that have extended to the middle cranial fossa has been successfully applied and is described.

Adolescent↗
PubMed1991

Effect of age at onset of deafness on children's speech perception abilities with a cochlear implant.

The speech perception abilities of 37 children with cochlear implants (single-channel or multichannel) were examined as a function of age at onset of deafness. There was no significant difference in the speech perception abilities of implanted children who were born deaf and those of implanted children who lost their hearing during the first 3 years of life. In contrast, the performance of children whose age at onset of deafness was 5 years or later was significantly better than that of the children with congenital or early-acquired deafness on tests of stress pattern categorization, closed-set word identification, open-set identification of common phrases, and lipreading enhancement.

Age Factors↗
PubMed1991

Comparison of speech perception abilities in deaf children with hearing aids or cochlear implants.

The speech perception abilities of deaf children with a single- or multi-channel cochlear implant are compared with those of deaf children who derive substantial benefit from conventional hearing aids. The children with hearing aids have unaided pure-tone thresholds ranging from 90- to 110-dB HL through at least 2000 Hz, and aided thresholds of 30- to 60-dB HL. The group data show that the speech perception scores of the subjects with hearing aids were significantly higher than those of the subjects with implants on a range of speech perception measures. Although a few subjects with implants achieved scores as high as those who used hearing aids, the majority did not. Even though the children with implants receive substantial benefit from their devices, they continue to have limited auditory perception abilities relative to their peers who derive benefit from conventional hearing aids. The data highlight the importance of establishing hearing aid benefit in potential candidates for implant.

Auditory Threshold↗
PubMed1991

Medical imaging in cochlear implant candidates.

A retrospective study of preoperative radiographic surveys obtained in 85 cochlear implant patients was performed. A total of 90 cochlear implant patients were seen at our institution during the last 10 years. In three, the implant was placed at another institution. In two otosclerosis patients, no preimplant radiographic examination was obtained. Meningitis was the cause of deafness in 45 of 90 patients (50 percent); 28 of 40 pediatric age group patients (70 percent), and in 17 of 50 adult patients (34 percent). Thirty-three of 45 postmeningitis patients (73 percent) showed characteristic radiographic signs of sclerosing labyrinthitis or labyrinthitis ossificans. These signs were present in only one other patient who was deaf with unknown cause. Deformity of the inner ear sufficient to explain congenital deafness was noted in three cases; one Mondini deformity and two obliterated base of the cochlea (modiolus). Three otosclerosis patients who had preimplant radiographs, and one congenital syphilis patient showed classic radiographic signs of their respective diseases. Obliteration or stenosis of the round and/or the oval windows were observed in 26 cases drawn from all major etiologic groups. State-of-the-art high resolution, thin-section CT can demonstrate subtle changes that may be the only clue to the cause of deafness. MRI promises to be a useful technique to follow meningitis patients with membraneous labyrinth changes progressing to sclerosing labyrinthitis.

Adolescent↗
PubMed1991

Speech perception abilities of children with cochlear implants, tactile aids, or hearing aids.

The purpose of this experiment was first, to compare the performance of three matched groups of experimental subjects who used either a single-channel cochlear implant, a multichannel cochlear implant, or a two-channel vibrotactile aid on a battery of speech perception measures, and second, to compare the performance of subjects with residual hearing who used hearing aids to that of the three groups of experimental subjects. The results revealed that the subjects using hearing aids achieved the highest scores on all measures. The performance of the group of multichannel implant users was significantly higher than that of the single-channel implant users on tests involving discrimination of speech features, categorization of stress patterns, closed-set identification of familiar words, and identification of common phrases with and without visual cues. The performance of the subjects using 3M/House and Tactaid II devices was similar on all tests except those requiring integration of auditory or tactile cues and visual cues, on which the 3M/House device users achieved significantly higher scores than did the Tactaid II device users.

Adolescent↗
PubMed1990

Speech perception with a single-channel cochlear implant: a comparison with a single-channel tactile device.

Suprasegmental and segmental speech perception tasks were administered to 8 patients with single-channel cochlear implants. Suprasegmental tasks included the recognition of syllable number, syllabic stress, and intonation. Segmental tasks included the recognition of vowels and consonants in three modalities: visual only, implant only, and visual + implant. Results were compared to those obtained from artificially deafened adults using a single-channel vibrotactile device. The patterns of responses for both suprasegmental and segmental tasks were highly similar for both groups of subjects, despite differences between the characteristics of the subject samples. These results suggest that single-channel sensory devices, whether they be cochlear implants or vibrotactile aids, produce similar patterns of speech perception errors, even when differences are observed in overall performance level.

Adult↗
PubMed1990

Sigmoid sinus thrombosis diagnosis by contrasted MRI scanning.

Septic thrombosis of the transverse-sigmoid sinuses and the jugular bulb is a highly lethal condition. The presenting signs and symptoms of this disease entity are subtle and not in proportion to the magnitude of the problem. Later in the disease course, sudden fulminant findings appear. A high index of suspicion, combined with scanning techniques of either enhanced MRI or CT, allows prompt diagnosis and treatment. MRI enhanced with gadolinium-DTPA (Gd) is a valuable adjunct that confirms the diagnosis and delineates the extent of suspected pathology.

Abscess↗
PubMed1990

Preservation of hearing in neurofibromatosis 2.

Preservation of hearing in the neurofibromatosis 2 (central neurofibromatosis) patient has been infrequently documented. This goal can be attained in selected patients and should be more frequently accomplished in the future with improved diagnostic capabilities and improved surgical techniques. We report three patients in whom this elusive goal has been accomplished.

Adolescent↗
PubMed1990

Performance of deaf children with cochlear implants and vibrotactile aids.

A longitudinal study is under way to examine the speech perception and production skills of deaf children who use a single- or multi-channel cochlear implant, or a two-channel tactile aid. The speech perception data showed that the majority of subjects who achieved the highest scores on a range of measures used the multi-channel cochlear implant. The production data showed that all three types of sensory aids were effective in promoting production skills, with the cochlear implant users showing the greatest gains in this area.

Child↗
PubMed1989

Comparison of sensory aids in deaf children.

A speech perception hierarchy has been developed and applied to assess the influence of cochlear implants and tactile aids on the acquisition of auditory, speech, and language skills in deaf children. Encouraging improvements were noted with both types of sensory aids at the detection level. The House 3M and Nucleus cochlear implant designs appear to offer advantages over the Tactaid II in providing ancillary speech perception cues to deaf children. Preliminary observations suggest that the multichannel cochlear implant design may be superior to the single-channel coding scheme.

Auditory Threshold↗
PubMed1989

Monitoring of intraoperative auditory brainstem responses.

Intraoperative ABR monitoring provides a measure of reassurance when a surgical procedure places the cochlear nerve or its blood supply in jeopardy. ABR monitoring has demonstrated its place in the operating room during retrolabyrinthine vestibular nerve section for vertigo, and in acoustic neuroma operations, when hearing preservation is a high priority in surgical outcome.

Brain Stem↗
PubMed1988

The role of cochlear implants in deaf children.

Advances in technology regarding cochlear implantation and electroacoustic stimulation of the inner ears of deaf children has created cautious enthusiasm. The safety of cochlear implantation is now reasonably well established and language performance measures made over time are encouraging. When coupled with an effective (re)habilitation program, the cochlear implant promises to favorably influence the potential of deafened children.

Adolescent↗
PubMed1987

Relationships among selected measures of single-channel cochlear implant performance.

Relationships among a number of pre- and postimplant variables measured in 20 adults implanted with a single-channel cochlear implant were examined through a variety of univariate and multivariate statistical techniques. A large number of variables were analyzed to yield information on the relationships between pre- and postimplant performance, and among a variety of postimplant measures. Variables included: age; etiology and nature of deafness; type of implant worn; pre- and postimplant warble tone and speech detection thresholds; postimplant performance on the Monosyllable-Trochee-Spondee (MTS) and Environmental Sounds tests; postimplant electrical thresholds, uncomfortable loudness levels, and dynamic range; I.Q. scores; and postimplant discourse tracking performance with and without the implant. The difference score on the discourse tracking task, representing the auditory advantage over performance with lipreading alone, related substantively to a combination of variables including type of unit worn (Sigma versus Alpha), nature of deafness (progressive versus sudden), and etiology (meningitis versus nonmeningitis). Additionally, MTS and Environmental Sounds test scores were found to relate to one another and to etiology and nature of deafness.

Adolescent↗
PubMed1987

Electrically evoked brainstem responses in cochlear implant recipients.

Electrical stimulation of the auditory nerve in the profoundly deaf population through implanted cochlear prostheses has increased the need for reliable electrophysiologic assessment tools. We have recorded electrically evoked brainstem responses (EABRs) in 21 subjects who have received a 3M/House cochlear implant. Recordings have been made, both intraoperatively and postoperatively, in the laboratory setting. The recording technique, methods of stimulus artifact suppression, and results of our measurements are described. Clinical applications of this technology are suggested.

Adolescent↗