Shelley Witt

Recognition of familiar melodies by adult cochlear implant recipients and normal‐hearing adults

Abstract The purpose of this study was to compare melody recognition and pitch perception of adult cochlear implant recipients and normal-hearing adults and to identify factors that influence the ability of implant users to recognize familiar melodies. Forty-nine experienced cochlear implant recipients and 18 normal-hearing adults were tested on familiar melody recognition. The normal-hearing adults were significantly (p < 0.0001) more accurate than implant recipients. Implant recipients showed considerable variability in perception of complex tones and pure tones. There were significant negative correlations between melody recognition, age at the time of testing, length of profound deafness and complex-tone perception, and significant positive relations between melody recognition and speech recognition scores.

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° 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.

Effects of Frequency, Instrumental Family, and Cochlear Implant Type on Timbre Recognition and Appraisal:

The purpose of this study was to compare postlingually deafened cochlear implant recipients and normal-hearing adults on timbre (tone quality) recognition and appraisal of 8 musical instruments representing 3 frequency ranges and 4 instrumental families. The implant recipients were significantly less accurate than the normal-hearing adults on timbre recognition. The implant recipients gave significantly poorer ratings than did the normal-hearing adults to those instruments played in the higher frequency range and to those from the string family. The timbre measures were weakly correlated with speech perception measures, but were significantly correlated with 3 cognitive measures of sequential processing.

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° 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° left from 45° 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.

Perception of rhythmic and sequential pitch patterns by normally hearing adults and adult cochlear implant users

Objective: This study compares the musical perception of 17 adult recipients of the Nucleus cochlear implant using two different format extraction processing strategies (F0F1F2 and MPEAK). Design: Over a 12 mo period, participants were alternately switched between two strategies every 3 mo. Performance was evaluated using three measures of rhythmic and sequential pitch perception. Results: Three individuals performed significantly better with the MPEAK strategy on one particular rhythm task, 11 participants performed better with the MPEAK strategy on another rhythm task, and no significant differences were found between the two strategies on a sequential pitch pattern task. Conclusions: Neither strategy seems clearly superior for perception of either sequential pitch or rhythmic patterns.

Recognition of "real-world" musical excerpts by cochlear implant recipients and normal-hearing adults.

Objective: The purposes of this study were (a) to compare recognition of “real-world” music excerpts by postlingually deafened adults using cochlear implants and normal-hearing adults; (b) to compare the performance of cochlear implant recipients using different devices and processing strategies; and (c) to examine the variability among implant recipients in recognition of musical selections in relation to performance on speech perception tests, performance on cognitive tests, and demographic variables. Design: Seventy-nine cochlear implant users and 30 normal-hearing adults were tested on open-set recognition of systematically selected excerpts from musical recordings heard in real life. The recognition accuracy of the two groups was compared for three musical genre: classical, country, and pop. Recognition accuracy was correlated with speech recognition scores, cognitive measures, and demographic measures, including musical background. Results: Cochlear implant recipients were significantly less accurate in recognition of previously familiar (known before hearing loss) musical excerpts than normal-hearing adults (p < 0.001) for all three genre. Implant recipients were most accurate in the recognition of country items and least accurate in the recognition of classical items. There were no significant differences among implant recipients due to implant type (Nucleus, Clarion, or Ineraid), or programming strategy (SPEAK, CIS, or ACE). For cochlear implant recipients, correlations between melody recognition and other measures were moderate to weak in strength; those with statistically significant correlations included age at time of testing (negatively correlated), performance on selected speech perception tests, and the amount of focused music listening following implantation. Conclusions: Current-day cochlear implants are not effective in transmitting several key structural features (i.e., pitch, harmony, timbral blends) of music essential to open-set recognition of well-known musical selections. Consequently, implant recipients must rely on extracting those musical features most accessible through the implant, such as song lyrics or a characteristic rhythm pattern, to identify the sorts of musical selections heard in everyday life.

Update on bilateral cochlear implantation.

Purpose of reviewProviding 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 findingsControlled 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. SummaryIt 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.

Speech Perception and Localization With Adults With Bilateral Sequential Cochlear Implants

This investigation reports measures of binaural hearing of all of our seven adults who have received sequential bilateral cochlear implants (range of time between implantation of 6 yr/8 mo and 17 yr). All subjects used both devices in everyday life. The internal array, number of channels, rate, and signal processing strategies were usually quite different between devices. Speech recognition was tested by using words in quiet and sentences in noise with the sentence stimuli presented from the front and the noise presented from the front, the right, or the left at a 90° angle. Bilateral localization was tested by using an everyday sounds test with stimuli presented from one of eight loudspeakers. Results showed that all subjects received a significant bilateral improvement on at least one speech perception test compared to either implant alone. Four of seven subjects with bilateral devices demonstrated some (root-mean-square error below 30°) localization abilities. The two subjects tested unilaterally before receiving a second implant showed a bilateral improvement on localization after implantation of the second side. We conclude that sequential implants can be beneficial even after many years of monaural use and even with very different cochlear implants.

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.

Long-Term Performance of Clarion 1.0 Cochlear Implant Users†

Objective/Hypothesis: To evaluate the long‐term performance of adult Clarion 1.0 cochlear implant users.