Potential Benefits of an Integrated Electric-Acoustic Sound Processor with Children: A Preliminary Report.

BACKGROUND: A number of published studies have demonstrated the benefits of electric-acoustic stimulation (EAS) over conventional electric stimulation for adults with functional low-frequency acoustic hearing and severe-to-profound high-frequency hearing loss. These benefits potentially include better speech recognition in quiet and in noise, better localization, improvements in sound quality, better music appreciation and aptitude, and better pitch recognition. There is, however, a paucity of published reports describing the potential benefits and limitations of EAS for children with functional low-frequency acoustic hearing and severe-to-profound high-frequency hearing loss. PURPOSE: The objective of this study was to explore the potential benefits of EAS for children. RESEARCH DESIGN: A repeated measures design was used to evaluate performance differences obtained with EAS stimulation versus acoustic- and electric-only stimulation. STUDY SAMPLE: Seven users of Cochlear Nucleus Hybrid, Nucleus 24 Freedom, CI512, and CI422 implants were included in the study. DATA COLLECTION AND ANALYSIS: Sentence recognition (assayed using the pediatric version of the AzBio sentence recognition test) was evaluated in quiet and at three fixed signal-to-noise ratios (SNR) (0, +5, and +10 dB). Functional hearing performance was also evaluated with the use of questionnaires, including the comparative version of the Speech, Spatial, and Qualities, the Listening Inventory for Education Revised, and the Children's Home Inventory for Listening Difficulties. RESULTS: Speech recognition in noise was typically better with EAS compared to participants' performance with acoustic- and electric-only stimulation, particularly when evaluated at the less favorable SNR. Additionally, in real-world situations, children generally preferred to use EAS compared to electric-only stimulation. Also, the participants' classroom teachers observed better hearing performance in the classroom with the use of EAS. CONCLUSIONS: Use of EAS provided better speech recognition in quiet and in noise when compared to performance obtained with use of acoustic- and electric-only stimulation, and children responded favorably to the use of EAS implemented in an integrated sound processor for real-world use.

Clinical case study review: steroid-responsive change in electrode impedance.

OBJECTIVE: This manuscript describes a case in which, based on clinical observations, we hypothesize that a change in a cochlear implant recipient's electrode impedance and performance was attributed to a change in the recipient's physiology rather than a device failure. Of particular note was the finding that electrode impedances decreased after a period of nonuse of the implant as well as after steroid treatment. STUDY DESIGN: Retrospective single-subject case study review. SETTING: Outpatient clinic. PATIENTS: This paper describes outcomes for a 75-year-old male cochlear implant user. INTERVENTION(S): A change in electrode impedance and a decrease in speech recognition were addressed through cochlear implant programming, periods of nonuse of the implant, provision of steroids, and bilateral cochlear implantation. MAIN OUTCOME MEASURE(S): The primary measures of interest were serial assessment of electrode impedance and speech recognition. Secondary measures included assessment of implant stimulation levels and electrophysiologic responses. RESULTS: Electrode impedances decreased (improved) after a period of nonuse of the implant as well as after provision of steroid treatment. Recipient performance also improved but did not return to baseline levels. CONCLUSION: Atypical fluctuations in electrode impedance were observed with periods of CI use and nonuse. Additionally, after a 10-month period of constant fluctuation of electrode impedances with atypical morphology, electrode impedances stabilized to normal levels with a typical morphology within 3 days of steroid treatment. Given these observations, we hypothesized that the change in this recipient's electrode impedance as well as the decrease in this implant recipient's performance may be attributed to his physiology rather than to the device failure. Changes in electrode impedance accompanied by a decrease in this patient's performance were successfully addressed by a period of nonuse of the implant, provision of steroids, and an increase in the pulse width of the biphasic pulsatile signal used for stimulation. It should be noted that the results of this case are anecdotal in nature and may not apply to all cochlear implant recipients experiencing electrode impedance changes and/or deterioration in performance.

Amplitude effects on electrocochleography outcomes.

OBJECTIVE: Electrocochleography measures in humans were examined to determine factors affecting results. STUDY DESIGN: Retrospective study. METHODS: Analysis was performed on data from 479 patients seen from 1998 to 2002 who underwent electrocochleography with a tympanic membrane electrode. Measures from click evoked electrocochleography (the summating potential to action potential ratio [SP/AP]) were compared with tone evoked electrocochleography (the SP amplitude). RESULTS: Findings indicate a strong correlation between click and tone measures if the AP from click measures was over 1 microV (P <.001), but no significant correlation between these measures if the AP was under 1 microV. Results were also analyzed with respect to patient hearing sensitivity and final diagnosis. CONCLUSION: Tympanic membrane electrocochleography is more efficacious when the AP from click stimulation is over 1 microV.

Phase III clinical trial results with the Vibrant Soundbridge implantable middle ear hearing device: a prospective controlled multicenter study.

OBJECTIVES: The goal of the study was to evaluate the performance of a semi-implantable middle ear hearing device (Vibrant Soundbridge System [VSB]; Symphonix Devices, Inc). STUDY DESIGN: A prospective, single-subject, repeated-measures multicenter study was conducted to determine the safety and efficacy of the VSB using analog and digital external processors. Measures included residual hearing, functional gain, speech recognition, acoustic feedback, occlusion, and patient self-assessment to determine satisfaction, perceived performance, and device preference compared with an appropriately fit acoustic hearing aid. Fifty-three adult subjects with moderate to severe sensorineural hearing loss were evaluated at 4 or more intervals after implantation. RESULTS: Improvements in satisfaction, performance, and preference were statistically significant with the VSB, as was functional gain across all test frequencies (P < 0.001). Occlusion and feedback were virtually eliminated. Aided speech recognition was comparable between VSB and the hearing aid. Residual hearing was unchanged. CONCLUSION: The VSB is a safe and effective treatment option for adults with moderate to severe sensorineural hearing loss.