Results with cochlear implantation in adults with speech recognition scores exceeding current criteria.

OBJECTIVES: The primary purpose of this study was to evaluate a group of postlingually deafened adults, whose aided speech recognition exceeded commonly accepted candidacy criteria for implantation. The study aimed to define performance and qualitative outcomes of cochlear implants in these individuals compared with their optimally fitted hearing aid(s). STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: All postlingually deafened subjects (N = 27), who were unsuccessful hearing aid users implanted between 2000 and 2010 with a preimplantation Hearing in Noise Test (HINT) score of 60% or more were included. INTERVENTION: We compared patients' preoperative performance (HINT score) with hearing aids to postoperative performance with the cochlear implant after 12 months of device use. In addition, the Hearing Handicap Inventory questionnaire was used to quantify the hearing-related handicap change perceived after the implantation. RESULTS: The study group demonstrated significant postoperative improvement on all outcome measures; most notably, the mean HINT score improved from 68.4% (standard deviation, 8.3) to 91.9% (standard deviation, 9.7). Additionally, there was a significant improvement in hearing-related handicap perceived by all patients. CONCLUSION: The envelope of implantation candidacy criteria continues to expand as shown by this study's cohort. Patient satisfaction and speech recognition results are very encouraging in support of treating those who currently perform at a level above the conventional candidacy threshold but struggle with optimally fitted hearing aids.

Telephone use and the factors influencing it among cochlear implant patients.

OBJECTIVE: To investigate telephone use in cochlear implant patients and to determine factors most likely to influence telephone use. METHODS: Surveys were mailed to 504 cochlear implant patients treated at Sunnybrook Health Sciences Hospital. RESULTS: Two hundred four patients returned surveys (49%), 87% were classified as telephone users. No differences were found in age, pre-implant hearing characteristics, and the majority of post-implant behaviors. Education and post-implant sound perception scores were found to be significantly different (P < 0.05) between telephone users and non-users. DISCUSSION: Telephone use among cochlear implant patients shows a positive increase compared to previous studies. In addition, we find that higher attained education and post-implant hearing scores to be independently correlated to telephone use.

Qualitative case studies of five cochlear implant recipients' experience with music.

Cochlear implantation has revolutionized the management of those who suffer from severe-to-profound hearing loss because many patients now achieve excellent speech understanding with objective testing. Nevertheless, speech understanding in noisy conditions and music appreciation remain significant challenges to cochlear implant (CI) users. Music appreciation is an extremely complex experience that is difficult to quantify through a conventional outcome study. This paper aims at documenting the experience of five CI patients with regard to music appreciation using qualitative techniques. This information was obtained through a semi-structured interview process. The interviews were then transcribed and analysed using a constant comparative method of qualitative description. The results together with medical case records were used to identify emerging themes. The common themes that evolved were: musical background, the experience of receiving the implant, current experience with music, attention, musical prediction ability, internal hearing, hedonic vs. critical listening, determination, and timbre perception. By documenting their experiences in this manner, novel insights into the patient perspective are provided that are unique to the literature. These descriptions will aid clinicians and researchers who work in the area of cochlear implantation to better understand the needs of their patients.

The effects of unilateral cochlear implantation on the tinnitus handicap inventory and the influence on quality of life.

OBJECTIVES/HYPOTHESIS: Cochlear implantation is now the standard of care in patients with significant sensorineural hearing loss. It is well known that patients with severe hearing loss also experience disabling tinnitus. The purpose of this study was to assess the effects of cochlear implants on the perception of tinnitus using the Tinnitus Handicap Inventory (THI). STUDY DESIGN: Prospective, longitudinal study of 142 cochlear implant patients. METHODS: The THI was administered to 142 patients pre- and postimplantation. Outcome measures were obtained 12 months after the implantation. Secondary analyses to examine the correlation between changes in THI scores and outcome measures such as Hearing Handicap Inventory, Hearing in Noise Test (HINT), and short-form 36 (SF-36) quality-of-life scores were performed. RESULTS: Patients demonstrated statistically significant reduction of the THI scores including its subscales (P < .001). Prior to implantation, 37% of patients described their tinnitus as moderate to severe. Postoperatively, this percentage decreased to 10%. Cochlear implantation resulted in complete tinnitus suppression in 37% and tinnitus reduction in another 29% of patients. THI scores significantly correlated with three domains of the SF-36 quality-of-life questionnaire, namely social, emotional, and general health domains. CONCLUSIONS: Cochlear implants have a significant suppressive effect on tinnitus in 66% of implant users. Although the reduction in the subjectively perceived tinnitus was statistically significant, it did not correlate with HINT; however, it did correlate with three quality-of-life domains, more significantly for those whose pretreatment conditions were moderate or worse.

A method for removing cochlear implant artifact.

When cortical auditory evoked potentials (CAEPs) are recorded in individuals with a cochlear implant (CI), electrical artifact can make the CAEP difficult or impossible to measure. Since increasing the interstimulus interval (ISI) increases the amplitude of physiological responses without changing the artifact, subtracting CAEPs recorded with a short ISI from those recorded with a longer ISI should show the physiological response without any artifact. In the first experiment, N1-P2 responses were recorded using a speech syllable and tone, paired with ISIs that changed randomly between 0.5 and 4s. In the second experiment, the same stimuli, at ISIs of either 500 or 3000ms, were presented in blocks that were homogeneous or random with respect to the ISI or stimulus. In the third experiment, N1-P2 responses were recorded using pulse trains with 500 and 3000ms ISIs in 4 CI listeners. The results demonstrated: (1) N1-P2 response amplitudes generally increased with increasing ISI. (2) Difference waveforms were largest for the homogeneous and random-stimulus blocks than for the random-ISI block. (3) The subtraction technique almost completely eliminated the electrical artifact in individuals with cochlear implants. Therefore, the subtraction technique is a feasible method of removing from the N1-P2 response the electrical artifact generated by the cochlear implant.

Acoustic change complexes recorded in adult cochlear implant listeners.

OBJECTIVES: The objectives of this study were to determine: 1) whether the acoustic change complex (ACC) could be reliably recorded in cochlear implant listeners and, 2) whether different speech sounds evoke distinct ACC patterns. DESIGN: Eight adults wearing the Nucleus-24 cochlear implant (CI) were tested using naturally produced speech tokens /si/ and /i/. Stimuli were tokens from the standardized UCLA version of the Nonsense Syllable Test. Using a repeated-measures design, participants were tested and retested within a 3-wk period. RESULTS: Intraclass correlation coefficients for grand mean and individual-response waveforms recorded from the syllables /si/ and /i/ ranged from 0.63 to 0.89 from test to retest. Also, ACC latencies signaling the onset of a vowel in /i/ were significantly earlier than those evoked by /si/. CONCLUSIONS: The ACC can be reliably recorded in individuals wearing CI. Furthermore, the naturally produced speech syllables /si/ and /i/ evoke distinct ACC patterns. Because of its good stability and the ease with which it can be recorded in individual CI listeners, the ACC can be evoked using complex signals (such as naturally produced speech syllables) when studying central auditory function in CI listeners.

Neural representation of amplified speech sounds.

OBJECTIVE: To determine if (1) evoked potentials elicited by amplified speech sounds (/si/ and /[symbol: see text]/) can be recorded reliably in individuals, (2) amplification alters neural response patterns, and (3) different amplified speech sounds evoke different neural patterns. DESIGN: Cortical evoked potentials were recorded in sound field from seven normal-hearing young adults in response to naturally produced speech tokens /si/ and /[symbol: see text]/ from the Nonsense Syllable Test. With the use of a repeated-measures design, subjects were tested and then retested within an 8-day period in both aided and unaided conditions. RESULTS: (1) Speech-evoked cortical potentials can be recorded reliably in individuals in both aided and unaided conditions. (2) Hearing aids that provide a mild high-frequency gain only subtly enhance peak amplitudes relative to unaided cortical recordings. (3) If the consonant-vowel boundary is preserved by the hearing aid, it can also be detected neurally, resulting in different neural response patterns for /si/ and /[symbol: see text]/. CONCLUSIONS: Speech-evoked cortical potentials can be recorded reliably in individuals during hearing aid use. A better understanding of how amplification (and device settings) affects neural response patterns is still needed.

Effects of stimulation rate on speech recognition with cochlear implants.

Phoneme and speech recognition were measured as a function of stimulation pulse rate in 12 listeners with three types of cochlear implants. Identification of consonants and vowels and recognition of words and sentences were measured in 5 Clarion C1 subjects fit with continuous interleaved sampling (CIS) processors having 4 or 8 electrodes, 4 Nucleus 24 subjects fit with CIS processors having 4, 8, 12 or 16 electrodes and 3 Clarion C2 subjects fit with CIS processors with 4, 8, 12 and 16 electrodes. Stimulation rates ranged from 200 to more than 5000 Hz per electrode, depending on the device, number of electrodes used and stimulation strategy. Listeners were also tested on the same materials with their original processor prior to receiving the experimental processors. All testing was done in quiet listening conditions with essentially no practice with the experimental processor prior to data collection. Listeners scored the highest with their original processor. Little difference in speech understanding was observed for listener scores with processors using different stimulation rates. Speech recognition was significantly poorer only at the lowest stimulation rate and at high rates that used noninterleaved pulses. Speech recognition was similar for processors using 8, 12 or 16 electrodes. Only 4-electrode processors produced a significantly poorer performance. These results suggest that patients with present commercial implants are not able to make full use of the number of channels of spectral information delivered by the present speech processors. In addition, the results show no significant change in performance as a function of stimulation rate, suggesting that high stimulation rates do not result in improved access to temporal cues in speech, at least under quiet listening conditions.