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Biomedical subjects

R S Tyler

Publications and source records attributed to R S Tyler.

At least 37 records · Page 2Linked to original sources
PubMed1996

A within-subject comparison of adult patients using the Nucleus F0F1F2 and F0F1F2B3B4B5 speech processing strategies.

This study compares the Nucleus F0F1F2 and F0F1F2B3B4B5 (also known as "Multipeak") of "Mpeak") processing schemes in 17 patients wearing the Mini Speech Processor. All patients had at least 18 months implant experience using the F0F1F2 processing strategy. For this study, they were switched to the F0F1F2B3B4B5 processing strategy for 3 months. They then returned to using the F0F1F2 strategy for 3 months, then used the F0F1F2B3B4B5 strategy again for 3 months, and lastly used the F0F1F2 strategy for 3 months. Performance' was evaluated with both schemes after each interval, using speech recognition tests and subjective ratings. Overall, differences between the results for the two processing schemes were not large. Average performance was somewhat better for the F0F1F2B3B4B5 strategy for word and sentence identification, but not for any of the other speech measures. Superior performance was observed in 8 patients with the F0F1F2B3B4B5 strategy. However, 6 of the 8 individuals were significantly better on only one of the six speech measures in the test battery. The other 2 patients performed better on two of the speech measures. Superior performance was also observed in 3 patients with F0F1F2 strategy for consonant recognition. For the remaining patients, there was little difference in their performance with the two strategies. Information transmission analyses indicated that the F0F1F2B3B4B5 strategy transmitted consonant duration and frication cues more efficiently than F0F1F2. Experience with one strategy appeared to benefit performance with the other strategy.

Adult↗
PubMed1996

Initial independent results with the Clarion cochlear implant.

OBJECTIVE: This paper reports some preliminary findings from patients, implanted at the University of Iowa, using the Advanced Bionics Clarion cochlear implant (version 1.0). We compared the performance of patients using both simultaneous analog and nonsimultaneous pulsatile processing strategies. The performance of Clarion patients was also compared with a group of patients who were using either the feature-extraction Nucleus cochlear implant or the compressed-analog Ineraid cochlear implant. DESIGN: One aim was to compare the analog and pulsatile stimulation in 19 patients using the Clarion implant. This aim could be accomplished only partially because of difficulties encountered in adequately fitting patients with the analog strategy. A second aim was to compare the Clarion users' performance with feature-extraction Nucleus and compressed-analog Ineraid patients. Comparisons were made with all patients having 9 mo experience postimplantation. RESULTS: Subjects performed better using the pulsatile mode compared with the analog mode. All subjects chose to use the pulsatile strategy after the first 3 mo of the study. Results comparing performance at 9 mo with our compressed-analog Ineraid and feature-extraction Nucleus patients indicated, in general, better average performance for the Clarion users. CONCLUSIONS: We conclude that the pulsatile version of the Clarion cochlear implant typically produces superior performance to the analog version of that device at this stage in its development. After 9 mo of experience, users of the Clarion implant are performing better than are users of the feature-extraction Nucleus and compressed-analog Ineraid cochlear implants with comparable amounts of experience.

Adult↗
PubMed1996

Cochlear implantation: relationships with research on auditory deprivation and acclimatization.

This paper reviews research on cochlear implantation relevant to deprivation and acclimatization with acoustical hearing aids. The term "deprivation" is used in its everyday sense to refer to the bilateral absence of acoustic stimulation. Results are reviewed from several sources, with detailed evidence presented from three groups of postlingually deafened adult patients and one group of prelingually deafened child patients, all implanted at the University of Iowa. Outcomes from implantation reveal consistent effects of deprivation, evidenced by significant negative correlations between accuracy of speech perception and the duration of profound/total deafness before implantation. Outcomes also show acclimatization in the form of significant improvements in performance over time after implantation. For adult patients, the level of performance measured shortly after implantation on average is about half the level measured eventually. Individually, 80% of the adult patients implanted in Iowa show significant performance improvements with time. On average, performance reached asymptote after 30 to 40 mo of implant use, although individual differences in the rate and amount of improvement are large. Absolute accuracy of speech perception with implants by adults is believed to be related to preoperative measures in three domains: 1) the number and physiological responsiveness of auditory ganglion cells and nerve fibers, indexed by measures of hearing sensitivity, duration of deafness, and age; 2) the responsiveness of the central nervous system, indexed by measures of cognitive and linguistic ability, and possibly also by age and duration of deafness; and 3) the motivation to learn to use the implant. Preliminary analyses suggest that the measures in the first domain are more strongly associated with the immediate benefit from implantation than with the subsequent improvement in performance over time.

Adolescent↗
PubMed1996

Report of the Eriksholm Workshop on auditory deprivation and acclimatization.

The terminology used in studies documenting changes in auditory performance following fitting of hearing aids has been diverse. Definitions for the auditory deprivation effect and auditory acclimatization are offered as a first step in rationalization. Two statements summarize current knowledge concerning auditory deprivation effects and auditory acclimatization, as well as considering the potential implications for research, field trial and clinical practice applications. Potential areas for future research are identified.

Auditory Perception↗
PubMed1996

Advantages and disadvantages expected and realized by pediatric cochlear implant recipients as reported by their parents.

Studies documenting subjective changes in quality of life of pediatric cochlear implant recipients are limited. In this study, parents of cochlear implant recipients completed a questionnaire requesting them to list advantages and disadvantages associated with their children's cochlear implant use. Preimplantation, benefits expected by parents included awareness of environmental sounds (89% of parents), improved speech perception (50%), and improved speech production (36%). Disadvantages expected included equipment maintenance and repair (21% of parents), slow progression of auditory and speech skills (21%), and resistance to wearing the device (18%). One year postimplantation, benefits reported by parents included environmental sound perception (76% of parents), speech perception (64%), and speech production (52%). Two years postimplantation, benefits reported by parents included perception of environmental sounds (76% of parents), speech perception (67%), and speech production (57%). Three years postimplantation, benefits reported included perception of environmental sounds (61% of parents), speech perception (78%), and speech production (74%). Postimplantation, 36%, 24%, and 52% of the parents had no disadvantages to report at the 1, 2, and 3-year intervals, respectively. At all postimplant intervals, disadvantages associated with the size and maintenance of equipment were listed most frequently (36%, 48%, and 22% of parents, respectively). Open-ended questionnaires may be useful when evaluating a child before or after cochlear implantation.

Adolescent↗
PubMed1995

Longitudinal assessment of physiological and psychophysical measures in cochlear implant users.

OBJECTIVE: The purpose of this study was to evaluate the effects of long-term electrical stimulation on human cochlear implant users. DESIGN: Repeated measures of electrically evoked auditory brain steam response (EABR) threshold, slope of the EABR growth function, and behavioral measures of threshold and dynamic range were made for a group of 22 Ineraid cochlear implant users and 19 Nucleus cochlear implant users over a 3- to 5-yr period. RESULTS: Data from both Ineraid and Nucleus cochlear implant users suggest that EABR threshold, slope of the EABR growth function, and behavioral measures of threshold and dynamic range remain reasonably stable for periods up to 5 yr postimplant. CONCLUSIONS: The results of this study show little evidence that prolonged electrical stimulation through daily use of a cochlear implant has deleterious effects on the auditory system.

Cochlear Implants↗
PubMed1995

Preliminary results with the Clarion cochlear implant in postlingually deaf adults.

A clinical trial of three different multichannel cochlear implants is in progress at The University of Iowa. Fifty postlingually deaf adults participated in a prospective randomized study of the Nucleus implant and the Ineraid device. Subsequently, 23 consecutive postlingually deaf adults have been implanted with the Clarion system. The speech perception performance obtained after 9 months of implant use with all devices was compared. In addition, Clarion patient results at 9 months were compared with long-term (36 months) results from subjects using the other two multichannel implants. Preliminary speech perception scores on the Iowa sentence test (sound-only) and NU-6 words (sound-only) demonstrate that the Clarion subjects, as a group, perform at higher levels than subjects using the other two systems. A wide range of performance is observed with all devices. The continuous interleaved pulsatile strategy of the Clarion device appears to be advantageous for this group of subjects.

Adult↗
PubMed1995

Tinnitus in the profoundly hearing-impaired and the effects of cochlear implants.

Of the 82 adult patients implanted in the Department of Veterans Affairs Cooperative Studies Program 304, 22 patients (27%) reported a bothersome tinnitus preoperatively. The tinnitus handicap experienced preoperatively in this profoundly deaf population is greater than that reported by mildly to severely hearing-impaired patients. The magnitude of their handicap was not correlated with age or preoperative hearing loss. After 2 years of cochlear implant use, a reduction in the tinnitus handicap was reported in 9, and an increase was noted in 3 of the 22 patients. In addition, 3 patients experienced a "severe" tinnitus 2 years after receiving a cochlear implant, whereas they had not reported a "bothersome" tinnitus preoperatively. One patient reported a tinnitus immediately after the surgery, but it subsided within a few days.

Adult↗
PubMed1995

Change in the quality of life of adult cochlear implant patients.

Changes in the quality of life perceived by patients over a 24-month period were examined by means of three questionnaires: the Patient Quality of Life Form, the Index Relative Questionnaire Form, and the Performance Inventory for Profound Hearing Loss Answer Form. In addition, the relationships among the three questionnaires were examined as a function of age, length of deafness, and a battery of selected audiological tests. The results of the study indicate that a cochlear implant makes significant, positive changes in the quality of life of patients and in their ability to communicate. The patients and their relatives differ somewhat in their perceptions of these changes. The degree of improvement in quality of life perceived by a patient as the result of an implant is a function of the years of deafness. In general, the longer an individual has been deaf, the less improvement in quality of life that is perceived.

Adult↗
PubMed1994

Results of multichannel cochlear implants in congenital and acquired prelingual deafness in children: five-year follow-up.

Postlingually deafened children, using multichannel cochlear implants, have achieved substantial improvement in their speech perception abilities and, in many instances, the results are better than in postlingually deafened adults. It has been suggested that children with prelingually acquired and congenital deafness would not receive similar benefits, since they have not developed an auditory memory. The purpose of this study is to analyze the speech perception and production performance over time of prelingually deafened children who have been using a multichannel cochlear implant for 1-5 years. Preliminary results comparing the effects of age at implantation and etiology of deafness on performance are also examined.

Adolescent↗
PubMed1994

Advantages of disadvantages expected and reported by cochlear implant patients.

An open-ended questionnaire was administered to 20 patients using the Nucleus multichannel cochlear implant and 21 patients using the Ineraid multichannel cochlear implant. Before surgery, they were asked to list the advantages and disadvantages that they expected from their cochlear implant. Advantages were expected in the categories of: (1) speech perception when speechreading can be used (65%); (2) environmental sound perception (58%); (3) psychological effects (14%); (4) speech perception when speechreading cannot be used (49%); (5) lifestyle and social effects (42%); and (6) speech production (5%). Disadvantages were expected in: (1) equipment malfunction (42%); (2) environmental sound perception (28%); (3) speech perception when speechreading can be used (7%); (4) psychological effects (24%); (5) speech perception when speechreading is not used (7%); and (6) lifestyle and social effects (7%). Concerns were also raised about the risk of surgery (9%). After several months (4-60 mo) of using their implant, patients were asked to list the advantages and disadvantages that they actually experienced. Advantages were reported in the categories of: (1) speech perception when speechreading can be used (86%); (2) environmental sound perception (79%); (3) psychological effects (49%); (4) speech perception when speechreading cannot be used (56%); (5) lifestyle and social effects (40%); (6) speech production (14%); and (7) the reduction of tinnitus (7%). Disadvantages were reported in: (1) equipment malfunction (54%); (2) environmental sound perception (53%); (3) speech perception when speechreading can be used (26%); (4) psychological effects (12%); (5) speech perception when speechreading is not used (21%); and (6) lifestyle and social effects (9%). Concerns were also noted about the cost of surgery (14%). Thirty patients had tinnitus preoperatively. Without hearing sound through the implant, 70 percent of these indicated that the cochlear implant had a positive effect on their tinnitus. When listening to speech through the implant, 83 percent reported that their tinnitus was reduced.

Adult↗
PubMed1993

Multivariate predictors of audiological success with multichannel cochlear implants.

To predict the audiological outcomes of 2 multichannel cochlear implants, a preoperative battery of historical, audiological, electrophysiologic, and psychologic variables from 48 postlingually deafened adults was tested in a prospective randomized clinical trial. Multivariate analyses were used to select and combine these preoperative variables in a predictive index that was significantly related to audiological outcome at 9 months. The preoperative variables included in the predictive index were duration of profound deafness, speech reading ability, residual hearing, cognitive ability, measures of compliance and engagement with treatment, and use of nonverbal communication strategies. The preoperative predictive index had correlations of .81 with the Iowa Sentences Test, and .78 with the NU-6 word understanding scores, both obtained in a sound-only test. Probability and percentile curves generated from these data offer considerable optimism in forecasting the range of likely audiological outcomes that would be realized by postlingually deafened adult candidates for multichannel cochlear implants.

Adult↗
PubMed1993

Intracochlear electrical tinnitus reduction.

Several reports have indicated that some cochlear implant patients experience a reduction in their tinnitus while listening to noise or speech. In the present study, two patients reporting bilateral tinnitus were selected from a group of adults with the Nucleus cochlear implant. They rated their tinnitus loudness and severity and completed the Tinnitus Handicap Questionnaire. The stimuli for electrical stimulation were charge-balanced pulse trains of various repetition rates (frequencies) and inter-electrode distances. A range of electrodes was chosen in each subject, including basal, medial and apical electrodes. For each condition, the hearing threshold level and the uncomfortable loudness level were determined. A range of stimulus levels between these two values were presented randomly. After each presentation, the patients rated the stimulus loudness and the tinnitus loudness on a 0 to 100 scale. These judgements were used to carefully determine the psychometric function between stimulus level and stimulus loudness, and between stimulus level and tinnitus loudness. All the parameters explored were important for maximizing the relationship between tinnitus reduction and stimulus loudness. First, the effectiveness of electrical stimulation in tinnitus reduction depended on the place along the cochlear partition. Second, a pulse rate of 125 Hz showed the greatest efficiency in terms of the current level needed to suppress tinnitus. Third, these two subjects showed rather poor performances in speech perception when using their speech processor in the usual condition and the hypothesis of an influence from tinnitus annoyance is suggested in addition to some more classical predicting factors of speech recognition in cochlear implant users.

Acoustic Stimulation↗
PubMed1992

Performance over time of congenitally deaf and postlingually deafened children using a multichannel cochlear implant.

The speech perception performance of 10 congenitally deaf and 3 postlingually deafened children who received the Cochlear Corporation multichannel cochlear implant was examined and compared. The children were tested preimplant and at 6-month intervals up to 2 years using the Monosyllable-Trochee-Spondee test (MTS), the Word Intelligibility by Picture Identification test (WIPI), and Phonetically Balanced Kindergarten (PB-K) or Northwestern University List 6 (NU-6) word lists. The postlingually deafened children exhibited significantly improved performance on open- and closed-set tests of word recognition after 6 months of implant use, a pattern similar to that of postlingually deafened adult implant users. In contrast, the congenitally deaf children did not exhibit measurably improved performance on speech perception tests until after 12 months or more of implant use. With as much as 18-24 months of use, however, some congenitally deaf children demonstrated limited open-set word recognition.

Acoustic Stimulation↗
PubMed1992

Performance over time with a nucleus or Ineraid cochlear implant.

This investigation determined whether the audiological performance of cochlear implant users varied with experience. Thirteen Nucleus and 14 Ineraid subjects were evaluated at 1, 9, and 18 mo after cochlear implant connection. Ten Nucleus and five Ineraid subjects were tested at 30 mo. On average, the ability of the subjects to recognize words and phonemes in an audition-only condition improved during the first 9 mo, as did their ability to recognize spondees in noise. The phoneme scores continued to improve during the next 9 mo. Environmental sound recognition improved gradually; significant improvement from the 1 mo scores was not noted until 18 mo. About half of the subjects who demonstrated poor word recognition at 1 mo showed significantly improved percent word correct scores by 18 mo. The Nucleus and Ineraid subjects did not differ in their patterns of change over time. An information transmission analysis performed on the subjects' consonant confusion matrices showed relatively little change for the nasality and place features during the first 18 mo, and relatively large change for the voice, duration, and frication features. Most improvement in the feature scores occurred during the first 9 mo.

Cochlear Implants↗