Biomedical subjects

Richard S Tyler

Publications and source records attributed to Richard S Tyler.

14 recordsLinked to original sources

PubMed2006

Tinnitus: standard of care, personality differences, genetic factors.

We comment on three areas related to tinnitus. The standard of care should include counseling that is collaborative and that addresses the overall emotional well-being of the patient. Utilizing management and coping strategies is desirable. Our new tinnitus activities treatment is an example of such a protocol. We believe that the notions of fearfulness and acceptance have the potential to be integrated into tinnitus treatment. Some patients reject, control or accept their tinnitus. We believe in some instances there may be a common genetic cause of tinnitus and depression. A potential candidate is the serotonin transporter gene SLC6A4.

Adaptation, Psychological↗

PubMed2006

Considerations for the design of clinical trials for tinnitus.

CONCLUSION: There are many possible control conditions to consider in designing research on tinnitus treatments. Some of the counseling procedures involve more than simply 'talking' or providing information, and it is important to make this distinction. Several good handicap scales are available, but we believe that 100-point interval scales have some superior attributes. Both primary and secondary measures of benefit should be used. Open trials have some merit, but should only be used cautiously. Several recent guidelines have been suggested for improving the design and reporting of clinical trials. OBJECTIVES: This paper reviews some basic considerations in the design of research to evaluate tinnitus treatments, particularly counseling and sound therapies. METHODS: We have reviewed some of the basic issues, referenced some relevant work, and provided some data supporting some of our assertions. RESULTS: We provide some recommendations for consideration for the design of clinical trials.

Clinical Trials as Topic↗

PubMed2006

Some benefits and limitations of binaural cochlear implants and our ability to measure them.

We review new recognition and localization skills in patients using one or two cochlear implant(s). We observed one unilateral patient who showed localization performance above chance. We also provide evidence for binaural processing in bilateral cochlear implant patients, even when tested with speech from the front without noise. We unsuccessfully attempted to find correlations between localization and squelch, between these variables and pre-implant threshold differences, or these variables and post-implant recognition differences. We strongly believe that new tests are needed to examine the potential benefit of two implants. We describe three tests that we use to show a binaural advantage: cued recognition, movement direction, and recognition with multiple jammers.

Auditory Threshold↗

PubMed2006

Effects of converting bilateral cochlear implant subjects to a strategy with increased rate and number of channels.

OBJECTIVES: Three different Advanced Bionics processing strategies were evaluated: 1) 8-channel, 813 pulses per second (pps), Continuous Interleaved Sampling (CIS); 2) 16-channel, 5,100 pps, HiResolution Paired (HiRes P); and 3) 16-channel, 2,900 pps, HiResolution Sequential (HiRes S). METHODS: Seven adult bilateral Clarion CII cochlear implant recipients who had been using a CIS processing strategy for at least 18 months participated in this study. Sentence recognition in multitalker babble from the front was collected on subjects using their CIS strategy and after subjects were programmed for the first time with HiRes P and HiRes S strategies. An ABAB design was implemented for 1 month whereby subjects used each HiResolution strategy every other day. Sentence recognition testing was repeated at the 1- and 3-month post-HiResolution test intervals. RESULTS: Comparisons between the CIS and HiResolution strategies showed immediate improvements for 5 subjects in favor of the HiResolution strategies. After 1 month of alternating between the HiRes P and HiRes S strategies, remarkably, 2 subjects showed improvements of 60%, 2 subjects showed improvements of 40%, and 2 subjects showed improvements of 30% over the CIS strategy that they had previously used for at least 18 months. The results after 3 months of use were consistent with those obtained at 1 month. CONCLUSIONS: The HiRes S and HiRes P strategies resulted in dramatic improvements in speech perception in noise for a subset of subjects who had been using the CIS strategy bilaterally. This finding demonstrates that these subjects were able to tolerate a more difficult signal-to-noise ratio. Further work is needed to determine the independent effects of rate versus number of channels.

Adult↗

PubMed2005

Benefit of wearing a hearing aid on the unimplanted ear in adult users of a cochlear implant.

The purpose of this investigation was to document performance of participants wearing a cochlear implant and hearing aid in opposite ears on speech-perception and localization tests. Twelve individuals who wore a cochlear implant and a hearing aid on contralateral ears were tested on their abilities to understand words in quiet and sentences in noise, and to localize everyday sounds. All speech stimuli were presented from the front, with the noise stimuli presented from the front, the right, or the left at a 90 degrees angle. Binaural summation in quiet and in noise, binaural squelch effects, and localization were studied to determine bilateral advantages. The magnitude of the monaural head shadow effect (the difference in unilateral performance when noise was facing the unilateral device vs. when the noise was opposite the unilateral device) also was studied. The test setup for localization was composed of an 8-speaker array spanning an arc of approximately 108 degrees in front of each participant. Group results yielded a statistically significant combined benefit of wearing a hearing aid in conjunction with a cochlear implant on opposite ears in noise conditions. Those participants who received a binaural advantage in 1 condition did not necessarily show a binaural advantage in another. Only 2 participants out of 12 were able to localize when wearing 2 devices. Further efforts are required to improve the integration of information from combined use of cochlear implant and hearing aid devices for enhancement of speech perception in noise and localization.

Aged↗

PubMed2004

Trade-offs between better hearing and better cosmetics.

A case study is reported of an adult bilateral cochlear implant patient who owns both a pair of ear-level and body-worn speech processors and chooses to wear them in unique configurations, knowingly compromising his auditory performance. The aim was to determine if differences in hearing could be quantified between these devices and to examine the size of these effects that would lend themselves to trading between performance and cosmetics. The patient reported wearing bilateral ear-level speech processors (programmed with the Cochlear Corporation spectral PEAK [SPEAK] coding strategy) 75% of the time for cosmetic and convenience reasons even though he "heard the best" with bilateral body-worn speech processors (programmed with the Cochlear Corporation advanced combination encoder strategy [ACE]). Speech perception and localization tests confirmed that this patient performed significantly better on monosyllabic phonemes in quiet (a difference from 60% to 75%) and localization (a total root-mean-squared-error difference from 22 degrees to 12degrees ) with bilateral body-worn speech processors and consistently rated various speech sounds as more clear than with bilateral ear-level units. There was a 2-dB difference in sentence reception threshold in noise, which was not statistically significant. These results suggest that clinicians should consider and provide options to patients when there are trade-offs to be made regarding understanding performance and cosmetics. Some individuals may choose better speech perception over cosmetics, and the ability to choose might result in greater compliance. The observations made here are relevant to hearing aid users as well.

Adult↗

PubMed2003

Cochlear implants: some likely next steps.

The history of cochlear implants is marked by large improvements in performance, especially over the past two decades and especially due to the development of ever-better processing strategies. Although the progress to date has been substantial, present devices still do not restore normal speech reception, even for top performers and particularly for listening to speech in competition with noise or other talkers. In addition, a wide range of outcomes persists, with some patients receiving little benefit using the same devices that support high levels of speech reception for others. The purpose of this review is to describe some likely possibilities for further improvement, including (a) combined electric and acoustic stimulation of the auditory system for patients with significant residual hearing, (b) use of bilateral implants, (c) a closer replication with implants of the processing steps in the normal cochlea, and (d) applications of knowledge about factors that are correlated with outcomes to help patients presently at the low end of the performance scale.

Acoustic Stimulation↗

PubMed2003

Update on bilateral cochlear implantation.

PURPOSE OF REVIEW: Providing a unilateral cochlear implant in a patient with a profound bilateral hearing loss has now been a standard clinical practice for more than a decade. Although results are often very good, normal hearing has not been restored. One exciting opportunity to improve hearing in this population is to provide a second implant. However, it is not obvious that bilateral electrical stimulation can be integrated by the central nervous system. This article describes binaural hearing and reviews currently published articles on binaural cochlear implants. RECENT FINDINGS: Controlled laboratory trials have focused on distinguishing different categories of potential binaural advantages. A potential summation effect occurs when the same stimulus is available at two ears. Listening in noise with two ears should be better than listening with one ear when the additional ear is away from the noise. This head shadow benefit results from acoustic effects, not physiologic ones. When the second ear is added near the noise source, a binaural squelch benefit can occur, requiring neural integration from both sides. Finally, two ears may improve sound localization. Binaural implantees generally benefit from head shadow effects. Only some benefit from summation and squelch effects. Most, but not all, show improved horizontal plane localization. SUMMARY: It is now appropriate to begin experimental studies of binaural cochlear implants. Preliminary results show promise to improve head shadow, a physical advantage, and sound localization. Some benefits have been observed for improved summation and squelch. These findings have demonstrated that the brain can integrate electrical stimulation from the two ears. Future studies will be required to maximize this binaural hearing.

Cochlear Implantation↗

PubMed2003

Electrical suppression of tinnitus with high-rate pulse trains.

HYPOTHESIS: Application of high-rate pulse trains (e.g., 4800 pps) to the cochlea may represent an effective treatment of tinnitus. BACKGROUND: Tinnitus is a widespread clinical problem with multiple treatments but no cure. A cure for tinnitus would restore the perception of silence. One plausible hypothesis for the origin of tinnitus associated with sensorineural hearing loss is that it is due to loss or alteration of the normal spontaneous activity in the deafferented regions of the cochlea. Electrical stimulation of the cochlea with 5000-pps pulse trains can produce spontaneous-like patterns of spike activity in the auditory nerve. METHODS: Eleven volunteer human subjects with bothersome tinnitus and high-frequency sensorineural hearing loss underwent myringotomy and temporary placement of a round window electrode. High-rate pulse train stimuli were presented at various stimulus intensities and tinnitus, and stimulus perception were scaled by the subject. Three cochlear implant recipients with tinnitus in the implanted ear underwent similar stimulation. RESULTS: Five of 11 (45%) of transtympanic subjects showed substantial or complete tinnitus suppression with either no perception or only a transient perception of the stimulus. Three showed tinnitus suppression only in association with the perception of the stimulus. Three showed no effects on tinnitus. A similar pattern of responses was seen in the cochlear implant subjects. CONCLUSIONS: Although the study lacked an ideal placebo control, the results are promising and support further research to develop a clinically useful intervention for this troubling disorder.

Adult↗

PubMed2003

Residual speech perception and cochlear implant performance in postlingually deafened adults.

OBJECTIVE: This study aimed at testing the post-hoc validity of the previously reported predictive index for postoperative cochlear implant performance, based on preoperative duration of deafness, and speech reception. STUDY DESIGN: Adult patients with postlingual severe to profound hearing loss, who were implanted with Cochlear Corporation CI-22 and CI-24 devices were included in this study. We studied the relationship between their postoperative word recognition scores and preoperative factors, namely, duration of deafness, and sentence recognition. We used the same predictive index reported in the previous study to predict their postoperative scores and test the model's agreement with the actual performance. RESULTS: We found that postoperative performance as measured by CNC word scores had an inverse relationship with the duration of deafness, and a direct correlation with the preoperative performance on CID sentence recognition tests. A nonlinear term [Duration / (1+CID)] was shown to improve the correlation coefficient of our predictive index. CONCLUSION: Some predictability of cochlear implant outcome is possible depending on the preoperative duration of deafness and speech recognition abilities. Preoperative residual speech recognition acts as a "trophic factor" that protects the spiral ganglion and/ or the central auditory pathways from degeneration. In other words, it improves the expected postoperative word scores.

Cochlear Implantation↗

PubMed2003

Speech perception, localization, and lateralization with bilateral cochlear implants.

Five bilateral cochlear implant users were tested for their localization abilities and speech understanding in noise, for both monaural and binaural listening conditions. They also participated in lateralization tasks to assess the impact of variations in interaural time delays (ITDs) and interaural level differences (ILDs) for electrical pulse trains under direct computer control. The localization task used pink noise bursts presented from an eight-loudspeaker array spanning an arc of approximately 108 degrees in front of the listeners at ear level (0-degree elevation). Subjects showed large benefits from bilateral device use compared to either side alone. Typical root-mean-square (rms) averaged errors across all eight loudspeakers in the array were about 10 degrees for bilateral device use and ranged from 20 degrees to 60 degrees using either ear alone. Speech reception thresholds (SRTs) were measured for sentences presented from directly in front of the listeners (0 degrees) in spectrally matching speech-weighted noise at either 0 degrees, +90 degrees or -90 degrees for four subjects out of five tested who could perform the task. For noise to either side, bilateral device use showed a substantial benefit over unilateral device use when noise was ipsilateral to the unilateral device. This was primarily because of monaural head-shadow effects, which resulted in robust SRT improvements (P<0.001) of about 4 to 5 dB when ipsilateral and contralateral noise positions were compared. The additional benefit of using both ears compared to the shadowed ear (i.e., binaural unmasking) was only 1 or 2 dB and less robust (P = 0.04). Results from the lateralization studies showed consistently good sensitivity to ILDs; better than the smallest level adjustment available in the implants (0.17 dB) for some subjects. Sensitivity to ITDs was moderate on the other hand, typically of the order of 100 micros. ITD sensitivity deteriorated rapidly when stimulation rates for unmodulated pulse-trains increased above a few hundred Hz but at 800 pps showed sensitivity comparable to 50-pps pulse-trains when a 50-Hz modulation was applied. In our opinion, these results clearly demonstrate important benefits are available from bilateral implantation, both for localizing sounds (in quiet) and for listening in noise when signal and noise sources are spatially separated. The data do indicate, however, that effects of interaural timing cues are weaker than those from interaural level cues and according to our psychophysical findings rely on the availability of low-rate information below a few hundred Hz.

Adult↗

PubMed2002

Three-month results with bilateral cochlear implants.

OBJECTIVES: To evaluate possible binaural listening advantages for speech in quiet, speech in noise, and for localization in a group of postlingually deafened adults with two cochlear implants functioning independently after 3 mo experience. DESIGN: Nine postlingually deafened subjects who had received a Cochlear Corporation CI24M implant in each ear were evaluated on a number of tasks. The subjects all had audiometric or biographical (e.g., duration of deafness) differences between the ears. Word and sentence materials were presented to the subjects in quiet and in noise with the signal always in the front and the noise from the front or either side. Results are reported for each ear and for both ears with the noise on either side. This allowed evaluation of head shadow and squelch effects. Additionally, localization ability was assessed for broadband noise presented either to the right or left of center at 45 degrees azimuth. Localization was assessed for each ear and for both ears. RESULTS: Results of speech testing in quiet showed a significant advantage for the binaural condition over the better ear in four subjects. In noise, with both signal and noise in front of the subject, a significant advantage of two ears over the better ear was found for four subjects. For noise to one side of the head, when the ear opposite the noise source was added to the ear ipsilateral to the noise, a significant advantage was demonstrated for seven of seven tested subjects. When the ear ipsilateral to the noise was added to the ear contralateral to the noise, a significant advantage was shown for only one of seven (noise on right) and three of seven (noise on left) tested subjects. The localization task showed that all seven tested subjects could discriminate 45 degrees left from 45 degrees right above chance with bilateral stimulation. Three subjects could perform the discrimination above chance with only one ear. However, performance with both ears was significantly better than performance with one ear for two of these latter subjects. CONCLUSIONS: We conclude that bilateral cochlear implants can provide real advantages, particularly when it is possible to utilize the ear that is away from a noise source, thus taking advantage of the head shadow effect. In addition, localization ability was generally better with two implants than with one.

Acoustic Stimulation↗

PubMed2002

Patients utilizing a hearing aid and a cochlear implant: speech perception and localization.

OBJECTIVE: The purpose of this pilot study was to document speech perception and localization abilities in patients who use a cochlear implant in one ear and a hearing aid in the other ear. DESIGN: We surveyed a group of 111 cochlear implant patients and asked them whether they used a hearing aid on their unimplanted ear. The first three patients who were available were tested on word and sentence recognition and localization tasks. Speech stimuli were presented from the front in quiet and in noise. In the latter conditions, noise was either from the front, the right, or the left. Localization was tested with noise bursts presented at 45 degrees from the right or left. In addition we asked the patients about their abilities to integrate the information from both devices. RESULTS: Speech perception tests in quiet showed a binaural advantage for only one of the three patients for words and none for sentences. With speech and noise both in front of the patient, two patients performed better with both devices than with either device alone. With speech in front and noise on the hearing aid side, no binaural advantage was seen, but with noise on the cochlear implant side, one patient showed a binaural advantage. Localization ability improved with both devices for two patients. The third patient had above-chance localization ability with his implant alone. CONCLUSIONS: A cochlear implant in one ear and a hearing aid in the other ear can provide binaural advantages. The patient who did not show a clear binaural advantage had the poorest hearing aid alone performance. The absolute and relative levels of performance at each ear are likely to influence the potential for binaural integration.

Cochlear Implants↗

PubMed2002

Binaural cochlear implants placed during the same operation.

OBJECTIVE: To evaluate the binaural listening advantages for speech in quiet and in noise and to localize sound when independently programmed binaural cochlear implants are used, and to determine whether ears with different hearing ability and duration of profound deafness perform differently with cochlear implants as well as to what extent preimplant psychophysical and physiologic assessment could be predictive of performance. STUDY DESIGN: Prospective study in which patients were prospectively selected to undergo bilateral implantation during a single surgical procedure at a tertiary referral center. All testing was performed with patients using their right, left, or both cochlear implants. Preimplant and intraoperative measures used electrical stimulation at the round window and stimulation through the cochlear implant. RESULTS: Bilateral implantation during the same operation did not cause any postoperative problems such as severe vertigo or ataxia. At 1 year, results of speech testing in quiet demonstrated a binaural advantage for 2 of 10 subjects. Speech-in-noise testing demonstrated that two implants were beneficial for two individuals. All subjects benefited from a head shadow effect when an ear with a better signal-to-noise ratio was available. The ability to localize sound was improved with binaural implants in all subjects. Preimplant psychophysical or physiologic measures were not predictive of eventual speech perception performance. CONCLUSION: Binaural cochlear implants can assist in the localization of sounds and have the potential in some individuals to improve speech understanding in quiet and in noise.

Adult↗