Middle-Ear Implant With MET V Transducer (Aka MET V System)

Inclusion Criteria: * Adult men or women, 18 years of age or older * Moderate to severe mixed hearing loss, as a result of a combination of sensorineural hearing loss and chronic ear disease, prior failed tympanoplasties, severe otosclerosis, radical mastoidectomy, or congenital abnormality as evidenced by the following in the ear to be implanted: * Bone conduction thresholds are measurable at 0.5,1,2,3 and 4 kHz * Bone conduction thresholds are 20 dB or poorer at greater than 2 kHz * Air conduction thresholds are 35 dB or poorer at 0.5,1,2,3 and 4 kHz * Air-bone gap in ear to be implanted is greater than 15 dB at three or more frequencies from 0.5 - 4 kHz * Word recognition appropriate for sensorineural component of loss * Non-fluctuating and stable hearing status a. as defined as by no significant change or progression in the bone conduction thresholds \>15dB at two consecutive octaves for at least 12 months. * English Speaking (fluent) * Realistic expectations for the device * Willingness to sign the informed consent and participate in the study Exclusion Criteria: * Vestibular disorder, including Meniere's Syndrome * Recurring otitis media over the past year (\>2/year) * Non-organic hearing loss * Retrocochlear hearing loss * Central auditory nervous system disorder * Medical contraindications to surgery or use of the device * Women who are pregnant or at risk of becoming pregnant * Developmentally delayed or manifesting organic brain dysfunction * Persons with physical or geographic limitations that may render them incapable of completing scheduled study visits