The Med-El EAS (Electric Acoustic system) using the Pulsar ci 100 FLEX eas or SONATA ti 100 FLEX eas and the DUET Speech Processor
Subjects will be placed into one of two study arms based on the residual hearing (pre-EAS) measured in their to-be-implanted ear. Arm 1 will include all subjects who meet the inclusion criteria set forth in the arm 1 section of this protocol. Arm 2 will include subjects who meet the inclusion criteria set forth in the arm 1 section with the exception that: in the ear to be implanted, the pure-tone air conduction thresholds at 250, 500, and/or 750 HZ will be greater than or equal to 0dB HL and less than 10 dB HL, and or, in the ear to be implanted, the pure-tone air conduction thresholds at 1000 and/or 1500 Hz will be greater than or equal to 0 dB HL and less than 60 dB HL, and/or in their best aided condition, they score 51-60% on monosyllabic word scores.
Both study arms will receive the same treatment throughout the study. Each subject will be assessed preoperatively and at designated intervals postoperatively to measure changes in hearing sensitivity and speech perception as a function of their acoustic alone, electric alone and EAS (electric + acoustic) conditions. Overall subject benefit will be measured as a function of the preoperative scores as compared to the 6 and 12-month post- EAS stimulation intervals, respectively the primary and secondary study endpoints.
Each subject will be intensively involved with the investigation for approximately fifteen (15) months. This time will be divided into the following four sequential sections:
Phase 1: 1 or more weeks of candidacy evaluation and preoperative testing
Phase 2: 3--4 weeks postoperative healing followed by initial cochlear implant (CI) stimulation.
Phase 3: EAS initial stimulation at 5--6 weeks post initial CI stimulation
Phase 4: 3, 6 and 12-month post -EAS stimulation evaluation and testing. Each subject[Right Quote]s involvement will transition to an optional long -term, semi-annual (every six months) follow -up for the remainder of the study. Note: This semi-annual follow up is not required by protocol, but is recommended if the site and subject have the time and willingness to do so.
The subject selection criteria and evaluation procedures specified below will be consistently applied to all prospective subjects, and uniform standards of subject selection will be maintained among all Investigators. Subjects that fall outside the candidacy criteria will not be enrolled.
Candidates for Study Arm 1 must meet the following requirements:
1. Audiologic tests suggest a normal to moderate hearing loss in the low to mid frequencies and sloping severe/profound hearing loss in the mid to high frequencies.. The non -implanted ear may fall outside of these criteria; however, threshold levels cannot be better than the indication criteria (for example, the non- implanted ear must be 60 dB or poorer at 1000 Hz, 70 dB or poorer at 2000--8000 Hz).
2. Pure-tone air -conduction threshold levels shall fall at or within the levels listed in the following chart
Frequency (Hz): 250 500 750 1000 1500 2000 4000 8000
Lower Limit: 10 10 10 60 60 70 70 70
Upper Limit: 65 65 75 *110+ *110+ *110+ *110+ *90+
*upper limit of audiometer
3. Pure-tone air -conduction thresholds for both ears are within 20 dB of each other at 250, 500 and 1000 Hz.
4.. Air/-bone gap at 500, 1000, 2000 and 4000 Hz should be <10 dB at two or more of these frequencies.
5. Minimal benefit from optimally fit hearing aid/s, preferably bilateral, with monosyllabic word scores in quiet of <=50% in the best -aided condition.
6. Normal middle ear anatomy and function (based on clinical assessment of tympanometry and acoustic reflex results). No prior middle ear surgery or history of post adolescent, chronic middle ear infections or inner ear disorders (i.e. vertigo or Meniere[Single Quote]s syndrome).
7. No evidence that hearing loss origin is retrocochlear.
8. Current user of bilateral acoustic hearing aids for at least 3 months. Note: If the subject has not been a successful hearing aid user (i.e. improper fit, feedback and/or discomfort from high frequency amplification), he/she must complete a hearing aid trial in the ear to be implanted for at least 1 month. If the ear to be implanted is poorer than the contralateral ear, then the subject must complete a hearing aid trial in both ears for at least 1 month to ensure that he/she is tested in the best -aided condition.
9. Adults 18--70 years of age at time of implantation.
10. Persons who currently exhibit sufficient understanding and communicative skills to comprehend general conversation in an
* oral/aural mode
* through normal conversation channels.
11. English as primary language.
12. Appropriate motivation and expectation levels.
Study Arm 2 candidates are those who meet the inclusion criteria listed above with the exception that in the ear to be implanted, the pure-tone air conduction thresholds at 250, 500, and/or 750 HZ will be greater than or equal to 0dB HL and less than 10 dB HL, and or, in the ear to be implanted, the pure-tone air conduction thresholds at 1000 and/or 1500 Hz will be greater than or equal to 0 dB HL and less than 60 dB HL, and/or in their best aided condition, they score 51-60% on monosyllabic word scores.