Biomedical subjects

R S Tyler

Publications and source records attributed to R S Tyler.

At least 19 recordsLinked to original sources

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↗

PubMed1992

Consonant recognition by some of the better cochlear-implant patients.

Fifty-four of the better cochlear-implant patients from Europe and the United States were tested on two consonant recognition tests using nonsense syllables. One was produced in an accent appropriate for their own language by a male and a female talker. Recorded tokens of /ibi, idi, igi, ipi, iti, iki, ifi, ivi, ifi, isi, izi, imi, ini/ were presented. With the French syllables, six patients with the Chorimac device averaged 18% correct (6%-29%). With the German syllables, nine patients with the 3M/Vienna device averaged 34% correct (17%-44%), ten patients with the Nucleus device (tested in Hannover) averaged 31% correct (19%-42%), and ten patients with the Duren/Cologne device averaged 27% correct (10%-56%). With the English syllables, ten patients with the Nucleus device (tested in the United States) averaged 42% correct (29%-62%), and nine patients with the Symbion device averaged 46% correct (31%-69%). An information-transmission analysis and sequential information-transfer analysis of the confusions suggested that different implants provided differing amounts of feature information. The place of articulation feature was typically the most difficult to code for all implants. In the second test a male and a female talker recorded the stimuli /ibi, idi, igi, imi, ini, ifi, isi, izi/ in a single manner that was appropriate for all three languages. Six patients with the Chorimac device averaged 27% (13%-48%), ten patients with the Duren/Cologne implant averaged 29% (15%-75%), ten patients with the Nucleus device (tested in Hannover) averaged 40% (25%-58%), ten patients with the Nucleus device (tested in the United States) averaged 49% (40%-60%), nine patients with the Symbion device averaged 61% (40%-75%), and nine patients with the 3M/Vienna device averaged 41% (29%-52%) correct.

Cochlear Implants↗

PubMed1992

Natural vowel perception by patients with the ineraid cochlear implant.

Vowel recognition was tested in 10 patients using the Ineraid cochlear implant. The vowels were produced by a male speaker in the context 'heed, hid, head, had, hawed, hood, who'd, hud' and 'heard'. Performance varied from 34 to 93% correct. A descriptive feature system for the vowels was determined from an acoustic analysis. An information transfer analysis of these features suggested that information about the first formant frequency, vowel duration and fundamental frequency was transmitted. Information about the second and third formant frequency was transmitted less well. A sequential information transmission analysis suggested that the features of the first formant and duration accounted for nearly 80% of the information transmitted. The fundamental frequency and second formant frequency information accounted for an additional 8%. Information provided by the third formant frequency was largely redundant.

Adult↗

PubMed1992

Review of pharmacologic treatment of tinnitus.

Recent research on the pharmacologic treatment of tinnitus is reviewed, emphasizing studies in which controls have been used. Several double-blind cross-over studies have found that lidocaine can reduce tinnitus in about 50 to 75 percent of subjects. Unfortunately, it cannot be used clinically because it must be administered intravenously and its effects are very brief. Other drugs have been much less successful. A few controlled studies have found success rates between 33 and 56 percent using oxazepam, clonazepam, sodium amylobarbitone, flunarizine, and eperisone hydrochloride. None of these studies have been replicated, however. Closely controlled studies using specified etiologic subgroups with subjective and objective psychophysical measurements are needed.

Antidepressive Agents↗

PubMed1992

Audiological management and performance of adult cochlear-implant patients.

We review the signal-processing strategies of three of the most common cochlear implants in use today, the single-channel House, the multichannel Nucleus, and the Ineraid devices. The results of 65 postlinguistically-deafened patients tested at The University of Iowa are reviewed. The tests include everyday sound, accent, word and sentence recognition, as well as noise/voice differentiation. For all tests, patients with the Nucleus and Ineraid cochlear implants outperformed those with the House implant. In general, selection criteria should focus on comparing the performance of Patients who have already received an implant. Prelinguistically-deafened adults are typically not good cochlear-impact candidates. Cochlear-implant teams should be aware of the enormous time commitment for testing and rehabilitation of these patients, and be prepared to handle frequent implant breakdowns. Nevertheless, cochlear-implant patients have been helped significantly be these devices.

Audiology↗

PubMed1991

What can we learn about hearing aids from cochlear implants?

Cochlear implants have changed the rehabilitation of profoundly hearing-impaired patients. A wide range of performance is reported for postlingually deaf adult patients using multichannel (Nucleus and Inerad) cochlear implants. For the 63 patients described here, performance ranges from 0 to 62% correct word recognition, from 0 to 98% lipreading enhancement measured as a percentage of the possible enhancement, and from 0 to 98% on understanding words in sentences. Prelingually deaf children also show benefit from their cochlear implants, but they require more time to obtain benefit than postlingually deaf children and adults. Experience with cochlear implants has suggested a few observations that could be useful to hearing aid development, including: (1) field trials are essential; (2) signal processing should preserve and enhance frequency resolution; (3) the fitting process for a sophisticated hearing aid may require several days to adjust properly; (4) fitting algorithms should focus on individuals rather than averages; (5) patients will wear a larger device if their handicap is great enough and if the improvement is sufficient; and (6) patients should and will accept expensive hearing aids.

Adult↗

PubMed1991

Psychological predictors of audiological outcomes of multichannel cochlear implants: preliminary findings.

The purpose of this research was to determine whether psychological variables were associated with the variability that characterizes the audiological performance of recipients of multichannel cochlear implants. Twenty-nine consecutive recipients of multichannel implants participated in a preoperative psychological assessment and audiological follow-up assessments after 18 months of implant use. Experimental cognitive measures that assess an ability to rapidly detect and respond to features imbedded in sequentially arrayed information accounted for up to 30% of the variance in implant outcome, suggesting the importance of cognitive abilities in implant outcome. Standardized measures of intellectual ability, however, were not predictive of outcome. The Health Opinion Survey, a measure of participatory engagement, was also a significant predictor of audiological outcome. Overall, the results implicated the importance of several specific psychological factors in the audiological outcome of cochlear implants in postlingually deafened adult recipients.

Adult↗

PubMed1991

Psychological change following 18 months of cochlear implant use.

Consecutive recipients of multichannel cochlear implants participated in preimplant as well as 9-month and 18-month psychological evaluations. Before receiving a cochlear implant, psychological tests indicated that the implant recipients were more depressed, suspicious, socially isolated, lonely, and socially anxious than was the general population. After 18 months of implant use, there was a significant reduction in depression, loneliness, social anxiety, social isolation, and suspiciousness. These changes in psychological state did not correlate with improved performance on audiological measures. The data suggest that although cochlear implants can have a positive effect on the emotional and behavioral status of persons with acquired postlingual profound deafness, the psychological outcome of implants is not simply a function of the audiological benefit assessed with standardized speech-based audiological tests.

Cochlear Implants↗

PubMed1991

Aural rehabilitation.

Aural rehabilitation involves a complete evaluation of the communication deficits and needs of the hearing-impaired patient as well as the provision of counselling and therapy. This article describes listening-assistive devices, speech production, and audiovisual training. Issues related to educational placement and tinnitus also are reviewed.

Cochlear Implants↗

PubMed1991

Tinnitus as a function of duration and etiology: counselling implications.

Based on the data of 528 tinnitus patients, information is presented concerning: (a) conditions and/or activities that affect tinnitus severity, (b) tinnitus symptoms as a function of etiology, and (c) changes in tinnitus symptoms as a function of time since onset. The four most common conditions and/or activities that reduce tinnitus severity were sleep, listening to TV/radio, being in noise, or being in quiet. Many conditions and/or activities increased tinnitus severity. The most common detrimental activities and/or conditions were noise exposure, being in a quiet place, emotional stress, loss of sleep, and physical exhaustion. Results also revealed that tinnitus loudness and severity increased as a function of years since onset. However, tinnitus pitch tended to remain stable. Meniere's patients experienced more annoyance, depression, and interference with sleep and also reported louder tinnitus than other etiologies. Tinnitus counselling should include: (a) informing patients that it is unlikely tinnitus annoyance will change dramatically, (b) alerting patients to the usefulness of tinnitus self-help groups, (c) helping patients to minimize time spent in activities and/or conditions where tinnitus severity is increased and to maximize time in activities and/or conditions where tinnitus severity is decreased, and (d) stressing the avoidance of noise exposure because of the relationship between noise-induced hearing loss and tinnitus.

Adolescent↗

PubMed1990

Relationships among loudness indexes in cochlear-implant patients.

The purpose of the experiment was to determine if the most-confortable-listening (MCL) levels and loudness-discomfort levels (LDLs) can be predicted from threshold measurements obtained from patients with cochlear implants using direct electrical stimulation. Psychophysical measurements of thresholds, MCLs, and LDLs with 125-Hz and 2000-Hz sinusoids were obtained from 16 patients with cochlear-implants 1 month after the connection of their ineraid processor (an auditory prosthesis). In general, the correlation coefficients among the loudness indexes obtained with a 125-Hz stimulus were similar to those for a 2000-Hz stimulus. Correlations between thresholds and MCLs were moderate, whereas correlations for thresholds and LDLs were fair. Correlations between MCLs and LDLs were high. This suggests that LDLs cannot be predicted from thresholds. On the other hand, these preliminary data suggest that MCLs may be reliably predicted from thresholds or LDLs to set the gain on a cochlear-implant processor.

Adult↗

PubMed1990

Characterization of tinnitus by tinnitus patients.

A questionnaire was administered to 528 tinnitus patients to obtain data on their reactions to tinnitus. Results include a discussion of: (a) population characteristics, (b) perceptual characteristics, (c) the impact of tinnitus on daily life, and (d) etiology. Significant gender differences are also discussed. Tinnitus was not an occasional phenomenon, but was present for more than 26 days per month in 74% of the patients. Other important findings about tinnitus include: (a) Hearing levels at 1000 and 4000 Hz were less than or equal to 25 dB HL for 18% of the tinnitus patients, which suggests that some patients had normal hearing or mild hearing losses; (b) the prevalence of tinnitus in patients with noise-induced hearing loss (NIHL) was 30% for males and only 3% for females; (c) about 25% of the patients reported tinnitus severity had increased since tinnitus onset; (d) the effects of tinnitus were more severe in patients who reported tinnitus as their primary complaint and in patients diagnosed as having Ménière's syndrome tinnitus; and (e) some patients reported that noise exacerbated their tinnitus, whereas others reported that a quiet background exacerbated their tinnitus.

Adolescent↗

PubMed1990

Effects of repair strategies on visual identification of sentences.

This investigation determined whether information elicited by repair strategies enhances an individual's ability to lipread a misperceived sentence. Five groups of subjects were each assigned one of five repair strategies: (a) asking the talker to repeat a sentence, (b) simplify it, (c) rephrase it, (d) say an important keyword, and (e) speak two sentences. Subjects viewed sentences spoken by six different talkers. When a subject did not recite a sentence verbatim, the talker performed the assigned repair strategy and then repeated the original sentence. A control group of subjects saw only the original sentence repeated twice. All five test groups demonstrated a significantly greater improvement for the second presentation score (referenced to the first presentation score) than the control group. The benefits provided by the repair strategies were independent of the talker, and benefits did not differ significantly among the groups.

Adult↗

PubMed1990

Comparison of the F0F2 and F0F1F2 processing strategies for the Cochlear Corporation cochlear implant.

In April 1985, an updated processing strategy became available for the Cochlear Corporation Nucleus cochlear implant. Whereas the original strategy codes only fundamental frequency, amplitude, and information in the second formant region, the newer strategy also codes frequencies in the first formant region. This investigation evaluated the speech recognition skills of five subjects who were experienced with both designs. On average, the addition of first formant information improved word identification in an audition-only condition and improved spondee recognition in noise. Scores for the NU 6 Monosyllabic Word Test and the Sentence Test Without Context improved from 8% (2-12%) to 28% words correct (10-42%), and from 31% (10-45%) to 64% words correct (39-84%), respectively. Scores for the Four-Choice Spondee Test in noise improved from 37% (25-50%) to 75% (45-90%). The percent correct scores for the Iowa 14-Item Consonant Confusion Test in an audition-only and vision-plus-audition condition did not vary with the change in processing strategy. However, an information transfer analysis performed on the responses to the consonant test in a vision-only and a vision-plus-audition condition suggested that the newer strategy enhances the transmission of the voicing, duration, and envelope features.

Adult↗

PubMed1990

The psychometric properties of a tinnitus handicap questionnaire.

The psychometric properties of a tinnitus handicap questionnaire are reported. There were two phases in this study. In Phase I, 87 questions were administered to 100 tinnitus patients. From their responses, 59 items that were either redundant, insensitive, or had low item-total correlations were eliminated. In Phase II, the resulting 27-item questionnaire was administered to 319 patients. Fifty-three of these patients also completed psychological and psychophysical measures that were used to validate the questionnaire. A factor analysis of patients' responses revealed a three-factor structure. These three factors appeared to reflect the physical, emotional, and social consequences of tinnitus (Factor 1), hearing ability of the patient (Factor 2), and the patients' view of tinnitus (Factor 3). Although the 27-item questionnaire had high internal consistency reliability and validity as reflected by correlations with life satisfaction and depression scales, it is recommended that only the items on the Factor 1 and the Factor 2 subscales be scored because of the low internal consistency reliability of the Factor 3 subscale. This questionnaire can be used to compare a patient's tinnitus handicap with the norm, identify specific areas of handicaps, and to monitor a patient's progress with particular treatment programs.

Female↗

PubMed1990

Intensity operating range measures as predictors of word-recognition ability in cochlear implant subjects.

The purposes of the experiment were to examine the appropriateness of pre- and post-implant intensity measures (thresholds, most comfortable listening level, and loudness discomfort level) as predictors of post-implant phoneme-recognition ability and to study the relationship between pre- and post-implant intensity measures. Pre-implant intensity measures were obtained on 16 subjects who were eventually implanted with either a Nucleus device (n = 8) or a Symbion device (n = 8). Phoneme scores on a NU-6 word list were obtained on these 16 subjects at 1 month post-implant. Post-implant intensity measures were also made on the 8 Symbion subjects at 1 month post-implant. The results showed that none of the pre-implant intensity measures correlated significantly with post-implant phoneme scores. In addition, pre-implant intensity measures did not correlate with the same post-implant intensity measures. However, post-implant MCLs and LDLs correlated significantly with phoneme scores as reflected by correlation coefficients that were larger than 0.8. These preliminary results suggest that although intensity measures may relate to phoneme-recognition ability, their use as predictive measures (as in pre-implant measures) for post-implant ability is questionable.

Acoustics↗

PubMed1990

Subjective ratings of noise-reduction hearing aids.

The effectiveness of seven commercially available noise-reduction hearing aids was evaluated using subjective ratings of continuous discourse. Subjective scales of listening comfort, speech quality, speech understanding, noise interference, and overall liking were used. Fifteen experienced hearing-aid users participated. Two hearing aids that used amplitude compression (Audiotone A-54 and Telex 363C), two hearing aids that used the Zeta Noise Blocker (two versions of a Maico SP147), and three hearing aids that proportionally attenuated the low-frequencies (Rion HB-69AS, Richards ASE-B, and Siemens 283 ASP) were evaluated. None of the noise-reduction hearing aids significantly altered group performance on any subjective scale. Individually, however, subjects responded differently to different noise-reduction hearing aids, indicating that some noise-reduction hearing aids may help some hearing-impaired individuals.

Acoustic Stimulation↗