BACKGROUND AND OBJECTIVES: The purpose of the study was to evaluate the changes in electrical stimulation levels, i.e. threshold (T) levels, comfortable (C) levels, dynamic range (DR), and electrode impedance values (EIVs) during the first year in cochlear implant users. SUBJECTS AND METHOD: The maps of 49 cochlear implant users (at least 1 year mapping), using the Nucleus device, were examined at the time of initial connection, and at 6 and 12 months post-initial stimulation. T levels, C levels, DR and EIVs were analyzed according to three frequency levels. RESULTS: During the first 6 months of implant use, C levels and DR increased significantly whereas T levels were stable. EIVs of current carrying electrodes decreased significantly from the connection to the 12-month visit. The changes of electrical stimulation levels did not differ among three frequency levels during the entire follow-up. CONCLUSION: During the first 6 months of implant use, C levels and DR increased significantly. Thus, an appropriate mapping in the first 6 month is critical to setup hearing capacity in implant users. The mapping should be performed under the best communication environment between the audiologist and the patient, and it makes correct setting of T levels from the initial connection period.
Auditory Threshold ; Cochlear Implants ; Electric Impedance ; Electric Stimulation ; Electrodes ; Hearing ; Humans ; Lifting ; Longitudinal Studies

BACKGROUND AND OBJECTIVES: Although popular as a method for aural rehabilitation with hearing impairment, hearing aids are susceptible to inflow of foreign materials such as water, sweat, and dust, causing corrosion of the circuit board and eventual device failure. Performance of hearing aids is evaluated by assessing the applicability of hydrophobic nano-coating technique using waterproof hearing aids electronic devices. SUBJECTS AND METHOD: Performance was evaluated using a Fonix 7000 for the maximum output sound pressure level (Max OSPL 90), high frequency average full on gain (HFA FOG), total harmonic distortion and input noise level for 13 hearing aids. Nine of the 13 hearing aids were tested after nano-coating was applied to 2.5 µm of thickness. Fro the immersion test, hearing aids were subjected to 1 m of depth of water and performance was immediately measured; they were also measured after a day and also after a month. RESULTS: In the coated group, Max OSPL 90, HFA FOG were significantly reduced but the corrosion of the circuit board was not observed. The four hearing aids without nano-coating failed to work immediately after the immersion test. However, there were no changes in performance after a month of immersion in any of the aids. For the non-coated group, corrosion of the circuit board was observed after 1 month. CONCLUSION: Nano-coating is a competitive technology and an advangtage to have to ensure waterproof effect and corrosion prevention. Thus it should be recognized as essential technology to enhance performance of hearing aids.
Correction of Hearing Impairment ; Corrosion ; Dust ; Equipment Failure ; Hearing Aids* ; Hearing Loss ; Hearing Tests ; Hearing* ; Immersion ; Noise ; Pilot Projects* ; Rehabilitation ; Sweat ; Water ; Weather

Background and Objectives: To analyze mapping changes in dynamic range (DR) and neural response threshold (NRT) as prognostic factors for cochlear implant (CI). To analyze whether postoperative speech perception performance could be predicted using DR change and initial NRT. Subjects and Methods: The speech comprehension data of 33 patients with CI were retrospectively analyzed after 1, 3, 6, and 12 months of device use. All subjects were adult, postlingually hearing-impaired, and Cochlear Nucleus CI users. Speech perception performance was evaluated using aided pure tone audiometry, consonant, vowel, one-word, two-word, and sentence tests. Results: The averages of initial NRT and DR changes were 197.8±25.9 CU (104–236) and 22.2±18.4 CU (-15–79), respectively. The initial DR was 40.8±16.6 CU. The postoperative DR was 50.3±16.4 CU at 3 months, 58±12.3 CU at 6 months, and 62.9±10.4 CU at 12 months. A gradual increase of DR was observed during the first year of CI. Compared with the initial DR, significant increases in DR were observed at 3 (p<0.05), 6 (p<0.001), and 12 (p<0.001) months. Compared with initial speech performance outcomes, a significant gain in all performance outcomes was achieved at 12 months (p<0.001). Conclusions Patients with low NRT after CI surgery could initially set DR to a wider range and had better final speech perception outcomes. Conversely, patients with high NRT after CI surgery had to set up a gradual increase in DR while adjusting the T-C level, and the final speech perception outcomes were worse. DR and NRT, the main CI mapping variables, can help predict prognosis related to speech perception outcomes after CI surgery. In conclusion, the post-CI speech perception is better with a lower initial NRT, wider final DR, or younger age.