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Biomedical subjects

Richard T Miyamoto

Publications and source records attributed to Richard T Miyamoto.

17 recordsLinked to original sources
PubMed2006

In vivo and in vitro characterization of bone marrow-derived stem cells in the cochlea.

OBJECTIVES/HYPOTHESIS: Stem cell replacement therapy has the potential to treat or cure an array of degenerative neurologic disorders, including sensorineural deafness. However, little is known about the potential for marrow-derived stem cells (MSCs) to take on properties of spiral ganglion neurons. The main purpose of this prospective animal study was to evaluate the survival of MSCs transplanted into the gerbil cochlea. METHODS: Eight 3- to 4-month-old Mongolian gerbils were used as recipients. The animals received an intraperilymphatic transplantation of 100,000 green fluorescent protein (GFP)-positive MSCs with scala tympani injection and modiolar injection. Seven days after transplantation, MSC survival was evaluated by microscopic examination of frozen sections cut through the cochleae of the recipient animals. RESULTS: MSCs isolated from the TgN (ACTbEGFP) mouse line used in this study exhibited bright green florescence after five to seven passages in vitro. Seven days after postoperatively, most transplanted MSCs were found in the scala tympani and scala vestibule and only a small number located in the scala media in animals that received both forms of injection. There were no GFP-positive MSCs in the modiolus in animals with scala tympani injection. In contrast, the mean profile count in animals with modiolar injection was 28, which was the highest in all regions. Although MSCs have the potential to migrate, the anatomic barrier between the perilymphatic space and the modiolus might account for the absence of GFP-positive MSCs in this region. CONCLUSION: These findings may have important clinical implications as a means of delivering MSCs in the cochlea for cell replacement therapy.

Animals↗
PubMed2006

Divergence of fine and gross motor skills in prelingually deaf children: implications for cochlear implantation.

OBJECTIVE: The objective of this study was to assess relations between fine and gross motor development and spoken language processing skills in pediatric cochlear implant users. STUDY DESIGN: The authors conducted a retrospective analysis of longitudinal data. METHODS: Prelingually deaf children who received a cochlear implant before age 5 and had no known developmental delay or cognitive impairment were included in the study. Fine and gross motor development were assessed before implantation using the Vineland Adaptive Behavioral Scales, a standardized parental report of adaptive behavior. Fine and gross motor scores reflected a given child's motor functioning with respect to a normative sample of typically developing, normal-hearing children. Relations between these preimplant scores and postimplant spoken language outcomes were assessed. RESULTS: In general, gross motor scores were found to be positively related to chronologic age, whereas the opposite trend was observed for fine motor scores. Fine motor scores were more strongly correlated with postimplant expressive and receptive language scores than gross motor scores. CONCLUSIONS: Our findings suggest a disassociation between fine and gross motor development in prelingually deaf children: fine motor skills, in contrast to gross motor skills, tend to be delayed as the prelingually deaf children get older. These findings provide new knowledge about the links between motor and spoken language development and suggest that auditory deprivation may lead to atypical development of certain motor and language skills that share common cortical processing resources.

Age Factors↗
PubMed2005

Behavioral assessment of prelingually deaf children before cochlear implantation.

OBJECTIVES/HYPOTHESIS: To determine whether scores from a behavioral assessment of prelingually deafened children who present for cochlear implant surgery are predictive of audiological outcomes. STUDY DESIGN: Retrospective review of longitudinal data collected from 42 children with prelingual hearing loss who presented for a cochlear implant before age 5 years. METHODS: The Vineland Adaptive Behavioral Scales (VABS) was administered during the preimplant workup. Standardized scores reflect daily living skills, socialization, and motor development compared with a normative sample. Regression analyses were conducted to determine whether any subject variables were related to VABS scores. Mixed-model analyses were computed to determine whether preimplant VABS scores were predictive of longitudinal spoken-language data obtained after cochlear implant surgery. RESULTS: Motor scores tended to be higher than nonmotor scores. Nonmotor scores were significantly lower than the normative mean and decreased with testing age. Children with acquired deafness demonstrated lower motor scores than children with congenital causes. Children with higher motor scores demonstrated significantly higher performance on language, vocabulary, and word recognition tests than children with lower motor scores. Nonmotor domains were not as robustly related to spoken-language measures, although similar trends were observed. CONCLUSION: Profound deafness and language delay may confound the assessment of daily living skills and socialization in the population studied. Motor development appears to proceed normally in prelingually deafened children and is a preimplant predictor of spoken-language outcome in young infants and children with cochlear implants, a finding consistent with the large body of work establishing links between perceptual-motor and language development.

Activities of Daily Living↗
PubMed2005

Cochlear implantation in deaf infants.

OBJECTIVES: With the application of universal newborn hearing screening programs, a large pool of newly identified deaf infants has been identified. The benefits of early intervention with cochlear implants (CI) is being explored. Mounting evidence suggests that age at implantation is a strong predictor of language outcomes. However, new behavioral procedures are needed to measure speech and language skills during infancy. Also, procedures are needed to analyze the speech input to young CI recipients. STUDY DESIGN: Cohort-sequential. METHODS: Thirteen infants with profound hearing loss who were implanted between the ages of 6 to 12 months of age participated in this study. Eight participated in two new behavioral methodologies: 1) the visual habituation procedure to assess their discrimination of speech sounds; 2) the preferential looking paradigm to assess their ability to learn associations between speech sounds and objects. Older implanted infants and normal-hearing infants were also tested for comparison. The pitch of mothers' speech to infants was analyzed. RESULTS: Patterns of looking times for the very early implanted infants were similar to those of normal hearing infants. Mothers' speech to infants with CIs was similar in pitch to normal-hearing infants who had the same duration of experience with sounds. CONCLUSIONS: No surgical or anesthetic complications occurred in this group of infants, and the pattern of listening skill development mirrors that seen in normal-hearing infants. Mothers adjust their speech to suit the listening experience of their infants.

Audiometry↗
PubMed2004

Communication abilities of children with aided residual hearing: comparison with cochlear implant users.

OBJECTIVE: To compare the communication outcomes between children with aided residual hearing and children with cochlear implants. DESIGN: Measures of speech recognition and language were administered to pediatric hearing aid users and cochlear implant users followed up longitudinally as part of an ongoing investigation on cochlear implant outcomes. The speech recognition measures included the Lexical Neighborhood Test, Phonetically Balanced-Kindergarten Word Lists, and the Hearing in Noise Test for Children presented in quiet and noise (+5 dB signal-to-noise ratio). Language measures included the Peabody Picture Vocabulary Test: Third Edition (PPVT-III), the Reynell Developmental Language Scales, and the Clinical Evaluation of Language Fundamentals-Revised. Subjects The experimental group was composed of 39 pediatric hearing aid users with a mean unaided pure-tone average threshold of 78.2 dB HL (hearing level). The comparison group was composed of 117 pediatric cochlear implant users with a mean unaided pure-tone average threshold of 110.2 dB HL. On average, both groups lost their hearing at younger than 1 year and were fitted with their respective sensory aids at 2 to 2.6 years of age. Not every child was administered every test for a variety of reasons. RESULTS: Between-group performance was equivalent on most speech recognition and language measures. The primary difference found between groups was on the PPVT-III, in which the hearing aid group had a significantly higher receptive vocabulary language quotient than the cochlear implant group. Notably, the cochlear implant group was substantially younger than the hearing aid group and had less experience with their sensory devices on this measure. CONCLUSION: Data obtained from children with aided residual hearing can be useful in determining cochlear implant candidacy.

Audiometry, Pure-Tone↗
PubMed2004

Cochlear implantation in adults with prelingual deafness. Part I. Clinical results.

OBJECTIVES/HYPOTHESIS: To examine the hypothesis that the newer generations of cochlear implants could provide considerable speech understanding to late-implanted, prelingually deaf adult patients. STUDY DESIGN: Retrospective review. METHODS: Speech perception scores of 103 patients with long-term prelingual deafness obtained from the recent clinical trials were compared with other previously published results. RESULTS: Unlike patients receiving implants in early childhood, the audiologic performance of most patients with long-term prelingual deafness rapidly approached asymptotic levels within 1 year after implantation. Beginning at 3 months postimplantation, statistically significant improvement was noted in their speech perception scores compared with their preimplant levels. However, the average performance plateau achieved by this group of patients was significantly below the levels published for postlingual patients. No statistically significant differences were observed between the test scores at any testing interval among patients with different devices. CONCLUSIONS: Most patients with long-term prelingual deafness achieve their performance plateau within 1 year after implantation. The results suggest that patient characteristics, rather than device properties, are likely to be the major contributing factor responsible for the observed audiologic outcomes.

Adolescent↗
PubMed2004

Cochlear implantation in adults with prelingual deafness. Part II. Underlying constraints that affect audiological outcomes.

OBJECTIVES/HYPOTHESIS: To discuss the underlying physiological and anatomical constraints on audiological performance of late-implanted prelingually deafened adult cochlear implant patients. STUDY DESIGN: Retrospective review. METHODS: Published literature on the topic of auditory pathway responses to prolonged congenital deafness was reviewed. In particular, the authors sought to identify the anatomical and physiological changes that take place in both the peripheral and central auditory pathways in response to prolonged deafness, as well as how they are altered by chronic electrical stimulation. RESULTS: The currently available evidence suggests that the colonization of the auditory cortex by other sensory modalities is the main limiting factor in postimplantation performance, not the pathological degenerative changes of the auditory nerve, cochlear nucleus, or auditory midbrain. CONCLUSION: The reviewed evidence, although circumstantial, suggests that emphasizing aurally based educational programs before (with hearing aids) and after cochlear implantation could reduce the cortical colonization phenomenon and potentially improve postimplantation audiological performance of patients with long-term prelingual deafness.

Adult↗
PubMed2003

Cochlear implantation for tinnitus suppression.

A high prevalence of tinnitus in cochlear implant users has been demonstrated, but fortunately a large percentage of patients do report some degree of tinnitus suppression postoperatively. Improvements in the duration and intensity and the annoyance level and loudness of the perceived tinnitus postimplant have been demonstrated. The risk of worsening of the tinnitus percept after cochlear implantation is small.

Cochlear Implantation↗
PubMed2003

Speech perception skills of deaf infants following cochlear implantation: a first report.

OBJECTIVE: We adapted a behavioral procedure that has been used extensively with normal-hearing (NH) infants, the visual habituation (VH) procedure, to assess deaf infants' discrimination and attention to speech. METHODS: Twenty-four NH 6-month-olds, 24 NH 9-month-olds, and 16 deaf infants at various ages before and following cochlear implantation (CI) were tested in a sound booth on their caregiver's lap in front of a TV monitor. During the habituation phase, each infant was presented with a repeating speech sound (e.g. 'hop hop hop') paired with a visual display of a checkerboard pattern on half of the trials ('sound trials') and only the visual display on the other half ('silent trials'). When the infant's looking time decreased and reached a habituation criterion, a test phase began. This consisted of two trials: an 'old trial' that was identical to the 'sound trials' and a 'novel trial' that consisted of a different repeating speech sound (e.g. 'ahhh') paired with the same checkerboard pattern. RESULTS: During the habituation phase, NH infants looked significantly longer during the sound trials than during the silent trials. However, deaf infants who had received cochlear implants (CIs) displayed a much weaker preference for the sound trials. On the other hand, both NH infants and deaf infants with CIs attended significantly longer to the visual display during the novel trial than during the old trial, suggesting that they were able to discriminate the speech patterns. Before receiving CIs, deaf infants did not show any preferences. CONCLUSIONS: Taken together, the findings suggest that deaf infants who receive CIs are able to detect and discriminate some speech patterns. However, their overall attention to speech sounds may be less than NH infants'. Attention to speech may impact other aspects of speech perception and spoken language development, such as segmenting words from fluent speech and learning novel words. Implications of the effects of early auditory deprivation and age at CI on speech perception and language development are discussed.

Attention↗
PubMed2003

Pediatric neurotology.

Pediatric neurotology is a subspecialty encompassing the medical and surgical treatment of conditions involving the middle ear, inner ear and lateral skull base. Multiple otologic and neurotologic diseases exist. In the pediatric patient the most common neurotologic conditions are vertigo, complications of otitis media, cholesteatoma, hearing loss and facial paralysis. Vertigo is differentiated into peripheral and central vestibular abnormalities. Peripheral vestibular causes include Meniere's disease, benign paroxysmal positional vertigo, vestibular neuronitis, otitis media and labyrinthitis. The predominant lesions in our field causing central vestibular disorders are brainstem and posterior fossa tumors. Mastoiditis, meningitis, petrositis, sigmoid sinus thrombosis, extradural abscess, brain abscess, otitic hydrocephalus, cholesteatoma and cholesterol granuloma are complications of otitis media and middle ear disease. Sensorineural hearing loss is now readily treated with cochlear implantation. Facial nerve paralysis may result from infectious and other etiologies.

Child↗
PubMed2003

Language development in deaf infants following cochlear implantation.

OBJECTIVE: To evaluate the benefits of cochlear implantation in infancy and compare them to those obtained in children implanted at a slightly older age. MATERIAL AND METHODS: Using standard language measurement tools, including the Grammatical Analysis of Elicited Language--Presentence Level (GAEL-P) and the Reynell Developmental Language Scales, progress was documented in a child who received a cochlear implant in infancy and compared to that achieved in children implanted at older ages. A new measurement tool, the Visual Habituation Procedure, was used to document early skills and the results were compared to those obtained in normal-hearing infants. RESULTS: By the age of 2 years the subject implanted in infancy achieved scores on the GAEL-P which were nearly equivalent to those achieved at the age of 5 1/2 years by children implanted at later ages. Age-equivalent scores on the Reynell Developmental Language Scales were achieved by the subject implanted in infancy and the ability to discriminate speech patterns was demonstrated using the Visual Habituation Procedure. CONCLUSION: This report demonstrates enhanced language development in an infant who received a cochlear implant at the age of 6 months.

Age Factors↗
PubMed2003

Modeling open-set spoken word recognition in postlingually deafened adults after cochlear implantation: some preliminary results with the neighborhood activation model.

HYPOTHESES: Do cochlear implants provide enough information to allow adult cochlear implant users to understand words in ways that are similar to listeners with acoustic hearing? Can we use a computational model to gain insight into the underlying mechanisms used by cochlear implant users to recognize spoken words? BACKGROUND: The Neighborhood Activation Model has been shown to be a reasonable model of word recognition for listeners with normal hearing. The Neighborhood Activation Model assumes that words are recognized in relation to other similar-sounding words in a listener's lexicon. The probability of correctly identifying a word is based on the phoneme perception probabilities from a listener's closed-set consonant and vowel confusion matrices modified by the relative frequency of occurrence of the target word compared with similar-sounding words (neighbors). Common words with few similar-sounding neighbors are more likely to be selected as responses than less common words with many similar-sounding neighbors. Recent studies have shown that several of the assumptions of the Neighborhood Activation Model also hold true for cochlear implant users. METHODS: Closed-set consonant and vowel confusion matrices were obtained from 26 postlingually deafened adults who use cochlear implants. Confusion matrices were used to represent input errors to the Neighborhood Activation Model. Responses to the different stimuli were then generated by the Neighborhood Activation Model after incorporating the frequency of occurrence counts of the stimuli and their neighbors. Model outputs were compared with obtained performance measures on the Consonant-Vowel Nucleus-Consonant word test. Information transmission analysis was used to assess whether the Neighborhood Activation Model was able to successfully generate and predict word and individual phoneme recognition by cochlear implant users. RESULTS: The Neighborhood Activation Model predicted Consonant-Vowel Nucleus-Consonant test words at levels similar to those correctly identified by the cochlear implant users. The Neighborhood Activation Model also predicted phoneme feature information well. CONCLUSION: The results obtained suggest that the Neighborhood Activation Model provides a reasonable explanation of word recognition by postlingually deafened adults after cochlear implantation. It appears that multichannel cochlear implants give cochlear implant users access to their mental lexicons in a manner that is similar to listeners with acoustic hearing. The lexical properties of the test stimuli used to assess performance are important to spoken-word recognition and should be included in further models of the word recognition process.

Adult↗
PubMed2002

PET imaging of differential cortical activation by monaural speech and nonspeech stimuli.

Positron emission tomography imaging was used to investigate the brain activation patterns of listeners presented monaurally (right ear) with speech and nonspeech stimuli. The major objectives were to identify regions involved with speech and nonspeech processing, and to develop a stimulus paradigm suitable for studies of cochlear-implant subjects. Scans were acquired under a silent condition and stimulus conditions that required listeners to press a response button to repeated words, sentences, time-reversed (TR) words, or TR sentences. Group-averaged data showed activated foci in the posterior superior temporal gyrus (STG) bilaterally and in or near the anterior insula/frontal operculum across all stimulus conditions compared to silence. The anterior STG was activated bilaterally for speech signals, but only on the right side for TR sentences. Only nonspeech conditions showed frontal-lobe activation in both the left inferior frontal gyrus [Brodmann's area (BA) 47] and ventromedial prefrontal areas (BA 10/11). An STG focus near the superior temporal sulcus was observed for sentence compared to word. The present findings show that both speech and nonspeech engaged a distributed network in temporal cortex for early acoustic and prelexical phonological analysis. Yet backward speech, though lacking semantic content, is perceived as speechlike by engaging prefrontal regions implicated in lexico-semantic processing.

Acoustic Stimulation↗
PubMed2002

Cochlear implantation with large vestibular aqueduct syndrome.

OBJECTIVES: In this investigation, we report the outcomes of 14 adults (age >18 y) and 9 children (age <18 y) with radiographically proven large vestibular aqueduct syndrome (LVAS) who received cochlear implants at Indiana University School of Medicine. STUDY DESIGN: This is a retrospective case-control study detailing the outcomes of 23 patients with LVAS and 46 control patients implanted with Nucleus (Cochlear Corp., Englewood, CO), Clarion (Advanced Bionics Corp., Sylmar, CA), or Med-El (MED-EL Corp., Innsbruck, Austria) cochlear implants. METHODS: Performance data on pure-tone averages, speech detection thresholds, and a variety of auditory and speech recognition tasks from these patients with LVAS were compared with performance data obtained from a matched group of 46 cochlear implant users who did not have LVAS. Specific patient characteristics used in matching included the age of the patient, the age at implant of the patient, and whether the patient was pre- or postlingually deafened. Data for the adult group was analyzed using the Student t test, and data for the pediatric patient group was compared using a chi2 test. RESULTS: The results indicated positive outcomes for both pediatric and adult groups. With both adult and pediatric groups, auditory and speech recognition performance did not differ significantly between those patients with LVAS and control subjects. CONCLUSIONS: This study adds further support for the use of cochlear implantation in patients with LVAS. Cochlear implantation is beneficial and can be offered as an eventual treatment of LVAS if hearing loss progresses to profound levels in these patients.

Audiometry↗
PubMed2002

Changes in quality of life and the cost-utility associated with cochlear implantation in patients with large vestibular aqueduct syndrome.

OBJECTIVE: A group of 20 patients with large vestibular aqueduct syndrome was identified at the Indiana University School of Medicine. The major objective of this study was to explore the improvements in quality of life associated with cochlear implantation in patients with large vestibular aqueduct syndrome, as well as the cost-utility of cochlear implantation in this group. SETTING: A total of 70 patients were identified with large vestibular aqueduct syndrome through analysis of thin-section computed tomography of the temporal bone over the past 6 years at this medical center. Data collected from the medical records for each patient included demographic data, hearing-related statistics, implantation data, and audiometric data. Sixteen children and adults with large vestibular aqueduct syndrome had undergone cochlear implantation before the beginning of this study, and the remaining 54 children and adults were identified as undergoing treatment of progressive or fluctuant sensorineural hearing loss. Health utility indexes used in this analysis were taken through the use of the Ontario Health Utility Index, Mark III. The range of costs used for cost-utility analysis was derived from the costs of cochlear implantation at this medical center, as well as from costs associated with implantation published in the medical literature. METHODS: Participants were selected from the total population of patients with large vestibular aqueduct syndrome at this center who were postlingually deafened and who currently had severe hearing loss. Two groups were formed. These groups comprised either cochlear implant patients with large vestibular aqueduct syndrome or patients with large vestibular aqueduct syndrome currently using hearing aids. Ten of the 16 cochlear implant patients and 10 of the remaining 54 patients with large vestibular aqueduct syndrome met these criteria. Mark III health utility indexes were distributed to patients in each group and scored. Those health utility indexes not completed by the patients were scored by proxy, using the audiologist at this center who was the most familiar with the patient. Changes in quality of life associated with cochlear implantation were derived by comparison of the health utility index results of the two groups. Cost-utility measures were then made using discounted costs per quality-of-life years (QALYs) (5%), and a sensitivity analysis was performed that evaluated changes in scoring done by proxy. The cost-utility results were then compared with the cost-utilities derived from similar studies and associated with other disease states. RESULTS: Although both groups of patients had significant hearing loss, the hearing aid group had a better mean pure-tone average. The mean pure-tone average for the hearing aid group was 70.8 dB (SD 24.4), and the mean pure-tone average for the cochlear implant group was 107.0 dB (SD 21.7). Seven of the 20 health utility indexes were scored by proxy. Results from the base case indicate a 0.20 gain in health utility from cochlear implantation (hearing aid = 0.62, cochlear implant = 0.82, p = 0.037), resulting in a discounted cost per QALY of $12,774. Sensitivity analysis of the proxy scoring indicated that decreasing the hearing score one level on the health utility index resulted in a gain in health utility with cochlear implantation of 0.15, resulting in a discounted cost per QALY of $17,832. A decrease of the hearing score by two levels on the health utility survey resulted in no significant gain in quality of life with cochlear implantation. CONCLUSION: This study found an improvement in quality of life associated with cochlear implantation in postlingually deafened patients with large vestibular aqueduct syndrome. By weighing this improvement in quality of life against the significant difference noted between the pure-tone averages of each group, further strength can be given to this conclusion. This gain in quality of life, as well as the results derived for the cost-utility of cochlear implantation, was similar to that in previous published studies of cochlear implantation in all types of patients. These results also indicate a favorable cost-utility when compared with published data about other disease states. As patients with large vestibular aqueduct syndrome progress to profound levels of hearing loss, these results indicate that cochlear implantation can be offered as a beneficial, life-improving therapy.

Adolescent↗
PubMed2002

Effects of age at implantation in young children.

This study examined the effects of age at implantation on the development of communication abilities in children with early implantation. The 73 participants were prelingually deafened, received a cochlear implant before 5 years of age, and used current cochlear implant technology. The children were administered a battery of speech and language outcome measures before implantation and again at successive 6-month postimplant intervals. A mixed model analysis was used to examine the rate of growth in word recognition and language skills as a function of age at time of implantation. The results revealed significant improvements in communication skills over time. Spoken word recognition improved at a faster rate in the oral children with early implantation. However, the children who underwent implantation before 3 years of age had significantly faster rates of language development than did the children with later implantation. The oral children demonstrated more rapid gains in communication abilities than did the children who used total communication.

Age Factors↗