Kate Gfeller

Preservation of Hearing in Cochlear Implant Surgery: Advantages of Combined Electrical and Acoustical Speech Processing†

Objectives/Hypothesis: This study documents the importance of preserving residual low‐frequency acoustic hearing as those with more residual hearing are selected for cochlear implantation. Surgical strategies used for hearing preservation with a short hybrid cochlear implant are outlined. The benefits of preserved residual low‐frequency hearing, improved word understanding in noise, and music appreciation are described.

Accuracy of cochlear implant recipients on pitch perception, melody recognition, and speech reception in noise.

Objective: The purposes of this study were to (a) examine the accuracy of cochlear implant recipients who use different types of devices and signal processing strategies on pitch ranking as a function of size of interval and frequency range and (b) to examine the relations between this pitch perception measure and demographic variables, melody recognition, and speech reception in background noise. Design: One hundred fourteen cochlear implant users and 21 normal-hearing adults were tested on a pitch discrimination task (pitch ranking) that required them to determine direction of pitch change as a function of base frequency and interval size. Three groups were tested: (a) long electrode cochlear implant users (N = 101); (b) short electrode users that received acoustic plus electrical stimulation (A+E) (N = 13); and (c) a normal-hearing (NH) comparison group (N = 21). Pitch ranking was tested at standard frequencies of 131 to 1048 Hz, and the size of the pitch-change intervals ranged from 1 to 4 semitones. A generalized linear mixed model (GLMM) was fit to predict pitch ranking and to determine if group differences exist as a function of base frequency and interval size. Overall significance effects were measured with Chi-square tests and individual effects were measured with t-tests. Pitch ranking accuracy was correlated with demographic measures (age at time of testing, length of profound deafness, months of implant use), frequency difference limens, familiar melody recognition, and two measures of speech reception in noise. Results: The long electrode recipients performed significantly poorer on pitch discrimination than the NH and A+E group. The A+E users performed similarly to the NH listeners as a function of interval size in the lower base frequency range, but their pitch discrimination scores deteriorated slightly in the higher frequency range. The long electrode recipients, although less accurate than participants in the NH and A+E groups, tended to perform with greater accuracy within the higher frequency range. There were statistically significant correlations between pitch ranking and familiar melody recognition as well as with pure-tone frequency difference limens at 200 and 400 Hz. Conclusions: Low-frequency acoustic hearing improves pitch discrimination as compared with traditional, electric-only cochlear implants. These findings have implications for musical tasks such as familiar melody recognition.

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.

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.

Acoustic plus electric speech processing: preliminary results of a multicenter clinical trial of the Iowa/Nucleus Hybrid implant.

Aim: This communication details the latest preliminary results from an ongoing multicenter single-subject design clinical trial of the Iowa/Nucleus Hybrid 10-mm cochlear implant. Selection criteria, surgical strategies used for hearing preservation, and the benefits of preserved residual low-frequency hearing, improved word understanding in noise, and music appreciation are described. Patients and Methods: The device has been implanted in 48 individuals with residual low-frequency hearing. Results:Hearing preservation has been accomplished in 46/48 subjects. Acoustic speech perception has also been preserved. Combined acoustic plus electric speech processing has enabled most of this group of volunteers to gain improved word understanding as compared to their preoperative hearing with bilateral hearing aids. A subset of subjects with 12 months or more experience demonstrates CNC word understanding continues to improve more than 24 months after implantation. Improved word understanding in noise is also a benefit of acoustic plus electric speech processing. Conclusions:The improvement of speech in noise and melody recognition is linked to the ability to distinguish fine pitch differences as the result of preserved residual low-frequency acoustic hearing. Both of these measures are very important in real life to the hearing impaired. Preservation of residual low-frequency hearing should be considered when expanding candidate selection criteria for standard cochlear implants.

Music Perception with Cochlear Implants and Residual Hearing

Aim: The aims of this study were to examine the music perception abilities of Cochlear Nucleus Hybrid (acoustic plus electric stimulation) cochlear implant (CI) recipients and to compare their performance with that of normal-hearing (NH) adults and CI recipients using conventional long-electrode (LE) devices (Advanced Bionics: 90K, Clarion, CIIHF; Cochlear Corporation: CI24M, CI22, Contour; Ineraid). Hybrid CI recipients were compared with NH adults and LE CI recipients on recognition of (a) real-world melodies and (b) musical instruments. Patients and Methods: We tested 4 Hybrid CI recipients, 17 NH adults, and 39 LE CI recipients on open-set recognition of real-world songs presented with and without lyrics. We also tested 14 Hybrid CI recipients, 21 NH adults, and 174 LE CI recipients on closed-set recognition of 8 musical instruments playing a 7-note phrase. Results: On recognition of real-world songs, both the Hybrid recipients and NH listeners were significantly more accurate (p < 0.0001) than the LE CI recipients in the no lyrics condition, which required reliance on musical cues only. The LE group was significantly less accurate than either the Hybrid or NH group (p < 0.0001) on instrument recognition for low and high frequency ranges. Conclusions: These results, while preliminary in nature, suggest that preservation of low-frequency acoustic hearing is important for perception of real-world musical stimuli.

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.

Perceived Effectiveness of Mainstreaming in Iowa and Kansas Schools

The purpose of this study was to examine the perceived status of mainstreaming among music educators in Iowa and Kansas. A questionnaire was developed with items concerning years and type of teaching experience; area of music instruction; amount of educational preparation in special education; extent of instructional support in main-streaming students into regular music classes; the extent to which musical and nonmusical goals are primary concerns of music educators; the degree of difficulty in mainstreaming students with various handicapping conditions; and the perceived success of mainstreaming. Results of the study revealed the following: (1) slight differences among general, choral, and instrumental music specialists in their perceptions regarding mainstreaming; (2) no significant difference in responses among music educators with varied experience in working with mainstreamed students; (3) a low level of educational preparation for most music educators working with mainstreamed students; (4) a positive correlation between perceived success in mainstreaming and extent of instructional support; (5) consensus that students with certain types of handicapping conditions are more difficult to integrate into the music classroom; and (6) lack of consensus in primary instructional objectives for handicapped students.

Familiar melody recognition by children and adults using cochlear implants and normal hearing children

Abstract This study investigated the effects of age at time of testing, hearing history (age at hearing loss) and hearing status on melody recognition. Four groups were compared: children with normal hearing thresholds, and three groups of cochlear implant recipients (children with prelingual deafness, children with postlingual deafness, adults with postlingual deafness). Participants were tested for recognition of familiar melodies (no lyrics) in a closed-set task. Groups differed in accuracy in the following rank order (most to least accurate): children with normal hearing thresholds, adult cochlear implant recipients, children with postlingual deafness, children with prelingual deafness. Melody recognition scores were correlated with age, variables regarding hearing history, musical background/experience and speech perception scores. Copyright