To evaluate the safety and efficacy of the Esteem Totally Implantable Hearing System in subjects suffering from mild to severe hearing loss.

Title: Esteem® Totally Implantable Hearing System Clinical Trial

Purpose: To evaluate the safety and efficacy of the Esteem® Totally Implantable Hearing System (hereafter called the Esteem® System) in subjects suffering from mild to severe hearing loss.

Trial Design: This pivotal trial is designed as a prospective, multi-center, non-randomized, clinical trial to evaluate the safety and efficacy of the Esteem® System. For this trial the subject will act as his or her own control.

This trial has been designed to meet the United States' regulatory requirements.

Enrollment Size: It is currently estimated that 50-60 subjects will be enrolled in this trial.

Subject Population: Adult subjects who have mild to severe sensorineural hearing loss, have a healthy middle ear, have a speech discrimination score of equal to or better than 40%, and have previously worn a hearing aid for a minimum of 3 months with an average daily use rate of at least 4 hours are eligible for inclusion in the trial. See detailed inclusion/exclusion criteria for specifics.

Primary Objectives:

1. To demonstrate that the Esteem® System improves the speech threshold of sensitivity for hearing and identifying speech signals as well as or better than the pre-implant hearing aid (aided condition).

   Endpoint: Comparison of the speech reception threshold (SRT) using the Esteem® System (4 months post activation) as compared to the pre-implant aided condition.

2. To demonstrate that the Esteem® System at the 4 months post- activation visit is as effective as or better than the hearing aid for improving speech discrimination (intelligibility) as shown by the word recognition score at 50 dB.

   Endpoint: Comparison of the word recognition score using the Esteem® at 4 months post-activation compared to the pre-implant aided condition.

3. To determine the incidence of Serious Adverse Device Effects (SADE) and the incidence rate of device failures and replacements.

   Endpoint: The analysis of the incidence of SADEs and device failures and replacements at each follow-up.

4. To demonstrate that the subjects' cochlear function remains unchanged with the Esteem® System as shown by comparison of the subjects' pre-implant baseline bone conduction threshold versus the subjects' 4 month post-activation visit bone conduction threshold.

Endpoint: Comparison of bone conduction threshold (BC) using forehead placement at 4 months post activation compared to the pre-implant BC threshold.

Secondary Objectives:

1. To demonstrate that the Esteem® System at the 4 months post activation visit improves the 3-frequency (500, 1000, and 2000 Hz) pure tone average (PTA) when compared to the baseline unaided condition.
2. To demonstrate that the Esteem® System at the 4 months post-activation visit is as effective as or better than the hearing aid for improving speech discrimination (intelligibility) as shown by the QuickSIN (speech in noise) test results.
3. To show that the Esteem® System improves Quality-of-Life when compared to the baseline aided condition as shown by APHAB results.
4. To gather subject feedback and comments on the use of the Esteem® System relative to the pre-implant hearing aid (aided condition) as shown by the Esteem® Questionnaire.

Inclusion Criteria:

• Subject is 18 years old
• Subject understands the nature of the procedure and has signed the Subject Informed Consent Form prior to the procedure
• Subject is willing and able to comply with specified follow-up evaluations and understands the audiological test procedures and use of the Esteem System.
• Subject has mild to severe sensorineural hearing loss between 500 and 4000 Hz in the ear to be implanted with pure tone air-conduction threshold levels within the limits of a Hearing Aid (HA) as follow:

Freq (Hz) 500 1000 2000 3000 4000 LL* (dB HL) 30 35 35 35 35 UL* (dB HL) 100 100 100 100 100

*LL = Lower Level; UL = Upper Level

• Subject's air-bone gap is no greater than 10 dB at 4 of the 5 following frequencies: 500, 1000, 2000, 3000 and 4000 Hz.
• Subject has an unaided maximum word recognition score of greater than or equal to 60% with recorded delivery using a phonetically balanced word list at SRT + 40 dB or at maximum tolerable presentation level.
• Subject is a current user of a properly functioning and appropriately fit hearing aid. This is defined as the subject has used this aid for at least four (4) hours (average) per day (in the ear to be implanted) for at least three (3) months for a new aid or one (1) month for an adjusted aid.
• Subject's hearing aid, in the ear to be implanted, shall appropriately fit optimally.
• Subject has normally functioning eustachian tube
• Subject has normal tympanic membrane
• Subject has a normal middle ear anatomy
• Subject has adequate space for Esteem System implant determined via fine cut temporal bone CT scan
• Subject is a native speaker of the English language.
• Subject is a hearing aid user in the ear to be implanted.

Exclusion Criteria:

• Subject has a history of post-adolescent chronic middle ear infections, inner ear disorders or recurring vertigo requiring treatment, disorders such as mastoiditis, Hydrops or Meniere's syndrome or disease
• Subject has a history of otitis externa or eczema for the outer ear canal and the investigator believes this will affect the Esteem System implantation
• Subject has cholesteatoma or destructive middle ear disease
• Subject has life expectancy of two (2) years due to other medical conditions
• Subject has retrocochlear or central auditory disorders
• Subject is known to be suffering from any psychological, developmental, physical, or emotional disorder that the investigator feels would interfere with the surgery or follow-up testing
• Subject has a known history of fluctuating air conduction and/or bone conduction hearing loss over a one-year period of 15 dB in either direction at 2 or more frequencies (from 500 - 4000 Hz)
• Subject has sudden hearing loss due to unknown cause
• Subject has a history of disabling tinnitus, defined as tinnitus which required treatment.
• Subject is unable to adequately perform audiological testing
• Subject has a medical condition or undergoing a treatment that may affect healing and the investigator does not believe the subject is a good candidate for the trial.
• Subject has diabetes that is not well controlled with medication or diet and the investigator does not believe in his best medical judgment that the subject would be a good candidate for the trial
• Subject is pregnant at the time of device implant
• Subject has a history of keloid formation
• Subject has known hypersensitivity to silicone rubber, polyurethane, stainless steel, titanium and/or gold

Cumulative through 10 Month Post-Activation