Angelika Illg

Auditory brainstem implant: Part I. auditory performance and its evolution over time

Objective Evaluation of auditory performance and its evolution over time in patients with the auditory brainstem implant. Study Design Prospective study. Setting Tertiary referral center. Patients and Methods Between May 1996 and April 2000, 14 patients with neurofibromatosis type 2 underwent implantation with a multichannel auditory brainstem implant. Auditory performance data were obtained in 13 patients who had used their device on a regular daily basis for 1 to 41 months (average 19 months). Hearing evaluation was based on the results of four tests (vowel confusion, consonant confusion, Freiburger numbers, and speech-tracking test), which were performed with and without lip-reading at regular intervals after device activation. Results 12 patients received auditory sensation through the auditory brainstem implant immediately after device activation. In one patient, because of postoperative electrode migration, device activation was not successful. In this case, after the electrode array was repositioned, activation was successful. The results of the audiovisual mode 2 weeks after device activation revealed a lip-reading enhancement above the chance level in about 50% of the patients in the vowel confusion and speech-tracking tests and in 70% of the patients in the consonant confusion test. Lip-reading enhancement improved within the first 6 months and then entered a plateau phase, which was more prominent in the monosyllabic vowel and consonant tests. In the auditory alone mode, more than half of the patients showed their first positive result in the vowel test 3 months after device activation, but it took about 6 months until half of the patients revealed a result above the chance level in the consonant and Freiburger numbers tests. Open set speech recognition in the auditory alone mode (in the speech-tracking test) was not common and happened relatively late (within 1 year or later). Discussion and Conclusion Although auditory sensation appeared immediately after device activation, a period of 6 months was necessary for relearning and adaptation of the central auditory system to the altered form of auditory information presented by the auditory brainstem implant.

Cochlear Implantation in Children under the Age of Two: The MHH Experience with the Clarion® Cochlear Implant

This paper examines reports on the selection criteria, the surgical procedure, and the postoperative performance for children under the age of 2 implanted with the CLARION® Multi-Strategy™ Cochlear Implant (1.2 device). Eighteen children have been implanted since 1996 with a mean age at implantation of 18 months (range 11 to 23 months). All children were selected by means of a standardized preoperative diagnostic protocol. The surgical procedure used in older children was modified depending on the head and mastoid size, skull thickness, and recurrent otitis media. Auditory perception was tested prior to as well as 3, 6, 12, and 18 months following implantation by means of a standardized age-adapted test protocol. The electrode array was inserted without difficulty in all cases, with no complications to date. On average, auditory performance improved over time up to 18 months after implantation. Closed-set test scores increased by 25% to 55% in 18 months. Open-set test scores began to show improvement between 6 and 12 months postoperatively. Overall, our experience indicates that cochlear implantation in children under the age of 2 is relatively safe and reliable. The Clarion 1.2 device surgery can be performed without complications. Auditory performance results support the effectiveness of early implantation.

Speech comprehension in children and adolescents after sequential bilateral cochlear implantation with long interimplant interval.

Objective Identify likely predictors for the outcome after contralateral cochlear implantation with a long interimplant delay. Study Design Retrospective case reviews. Setting Outpatient cochlear implant (CI) center. Patients Seventy-three children and adolescents who underwent sequential bilateral cochlear implantation with an interval between both implantations of 5 years or longer. The mean age of the patients at the first and second cochlear implantations was 2.72 ± 1.52 and 11.57 ± 2.9 years, respectively. The mean duration of experience with both implants was 4.01 ± 1.57 years. Intervention Rehabilitative. Main Outcome Measures All 73 patients underwent periodic speech perception testing in quiet and noise. The most recent unilateral data for each side were statistically analyzed. The speech test results were evaluated by the age at first implantation, the interval between both implantations, the duration of hearing aid use in the second side, and the duration of the bilateral CI use. Results A statistically significant difference for speech test results was obtained between the early-implanted ears and the late-implanted ears for all children. These results were dependent on the interimplant interval. All age groups demonstrated significant differences (p > 0.05) for the second side between the speech test results and the interval between both cochlear implantations. In addition, statistically significant differences influenced by the duration of hearing aid use were found for speech test results for the second side. Experience was also a factor for the second CI, yielding significantly higher speech test scores with longer use. Conclusion The development of hearing abilities in a second-implanted side depends on the interimplant interval, the hearing aid use, and the duration of the second CI use.

Evaluation of the Bimodal Benefit in a Large Cohort of Cochlear Implant Subjects Using a Contralateral Hearing Aid

Objective To investigate the benefit of contralateral residual hearing in a large group of cochlear implant recipients with different degrees of residual hearing. Patients One hundred and forty-one adult patients (age in years: mean 58.82, min 16.27, max 88.20) wearing a cochlear implant and a contralateral hearing aid, bimodal. Intervention Rehabilitative. Main Outcome Measures All 141 patients underwent speech perception testing in quiet and noise with cochlear implant (CI) alone, and with CI and hearing aid (HA). Additionally, pure-tone air conduction threshold levels were measured in all subjects. The bimodal benefit was analyzed and correlations to the hearing threshold for different audiometric frequencies were calculated. Results Comparison between the scores for CI alone and CI + HA showed statistically significant advantages (p < 0.0001) in all four tests. The benefit for sentences in noise to each individual patient showed a negative correlation with the hearing threshold level of 125 Hz and 250 Hz, using a linear regression analysis applying the Spearman’s rho correlation coefficient (r = −0.32, −0.232), and a significant difference at p = 0.006, p = 0.007. The correlations involving speech understanding in sentences in noise, and the hearing level of 500 Hz and above, are not significant for the benefit obtained with a contralateral hearing aid. Conclusion The benefit of combined electric and acoustic hearing in bimodally fitted subjects depends mainly on residual hearing in the low-frequency range below 500 Hz. For bimodal fitting to yield significant benefits, hearing loss in the contralateral ear should not exceed 80 dB HL in the low frequencies.

Investigation of the effect of cochlear implant electrode length on speech comprehension in quiet and noise compared with the results with users of electro-acoustic-stimulation, a retrospective analysis

Objectives This investigation evaluated the effect of cochlear implant (CI) electrode length on speech comprehension in quiet and noise and compare the results with those of EAS users. Methodes 91 adults with some degree of residual hearing were implanted with a FLEX20, FLEX24, or FLEX28 electrode. Some subjects were postoperative electric-acoustic-stimulation (EAS) users; the other subjects were in the groups of electric stimulation-only (ES-only). Speech perception was tested in quiet and noise at 3 and 6 months of ES or EAS use. Speech comprehension results were analyzed and correlated to electrode length. Results While the FLEX20 ES and FLEX24 ES groups were still in their learning phase between the 3 to 6 months interval, the FLEX28 ES group was already reaching a performance plateau at the three months appointment yielding remarkably high test scores. EAS subjects using FLEX20 or FLEX24 electrodes outscored ES-only subjects with the same short electrodes on all 3 tests at each interval, reaching significance with FLEX20 ES and FLEX24 ES subjects on all 3 tests at the 3-months interval and on 2 tests at the 6- months interval. Amongst ES-only subjects at the 3- months interval, FLEX28 ES subjects significantly outscored FLEX20 ES subjects on all 3 tests and the FLEX24 ES subjects on 2 tests. At the-6 months interval, FLEX28 ES subjects still exceeded the other ES-only subjects although the difference did not reach significance. Conclusions Among ES-only users, the FLEX28 ES users had the best speech comprehension scores, at the 3- months appointment and tendentially at the 6 months appointment. EAS users showed significantly better speech comprehension results compared to ES-only users with the same short electrodes.

Long-Term Outcomes, Education, and Occupational Level in Cochlear Implant Recipients Who Were Implanted in Childhood

Objectives: To document the long-term outcomes of auditory performance, educational status, vocational training, and occupational situation in users of cochlear implants (CIs) who were implanted in childhood. Design: This retrospective cross-sectional study of 933 recipients of CIs examined auditory performance, education and vocational training, and occupational outcomes. All participants received their first CI during their childhood between 1986 and 2000. Speech comprehension results were categorized using the categories of auditory performance (CAP) arranged in order of increasing difficulty ranging from 0 to 8. 174 of the 933 pediatric recipients of CIs completed a self-assessment questionnaire regarding their education and occupational outcomes. To measure and compare school education, qualifications were converted into International Standard Classification of Education levels (ISCED-97). Occupations were converted into International Standard Classification of Occupation-88 skill levels. Data from the German General Social Survey (Allgemeine Bevölkerungsumfrage der Sozialwissenschaften/ALLBUS) for 2012 were used as a basis for comparing some of the collected data with the general population in Germany. Results: The results showed that 86.8% of the 174 participants who completed the survey used their devices more than 11 hr per day. Only 2% of the surveyed individuals were nonusers. Median CAP was 4.00 (0 to 8). Age at implantation was significantly correlated with CAP level (r = −0.472; p < 0.001). The mean ISCED level of the 174 surveyed recipients was 2.24 (SD = 0.59; range: 1 to 3). A significant difference (p = 0.001) between users’ ISCED levels and those of ALLBUS 2012 respondents was found. Participants’ ISCED levels and maternal educational levels were significantly correlated (r = 0.271; p = 0.008). The International Standard Classification of Occupation-88 skill levels were as follows: 5% achieved skill level 1; 77% skill level 2; 16% skill level 3; and 5% skill level 4. The average skill level achieved was 2.24 (range 1 to 4; SD = 0.57) which was significantly poorer (t(127) = 4.886; p = 0.001) than the mean skill level of the ALLBUS 2012 respondents (mean = 2.54; SD = 0.85). Conclusions: Data collection up to 17.75 (SD = 3.08; range 13 to 28) years post implant demonstrated that the majority of participants who underwent implantation at an early age achieved discrimination of speech sounds without lipreading (CAP category 4.00). Educational, vocational, and occupational level achieved by this cohort were significantly poorer compared with the German and worldwide population average. Children implanted today who are younger at implantation, and with whom more advanced up-to-date CIs are used, are expected to exhibit better auditory performance and have enhanced educational and occupational opportunities. Compared with the circumstances immediately after World War II in the 20th century, children with hearing impairment who use these implants have improved prospects in this regard.