• Sixty-five years of age or older at the time of the study and CMS-eligible as primary source of medical insurance coverage.
• Bilateral moderate to profound hearing loss in the low frequencies (up to 1000 Hz) and profound sensorineural hearing loss in the high frequencies (3000 Hz and above).
• Preoperative aided sentence score in quiet greater than or equal to 40% correct but less than or equal to 60% correct in the best aided condition on recorded AzBio sentences.
• English spoken as the primary language.
• Congenital hearing loss (for the purpose of this study, onset pror to 2 years-of-age).
• Preoperative aided sentence score less than 40% or greater than 60% correct in the best aided condition on AzBio sentences in quiet
• Ossification, absence of cochlear development or any other cochlear anomaly that might prevent complete insertion of the electrode array.
• Hearing loss of neural or central origin (e.g., deafness due to lesions on the acoustic nerve or central auditory pathway).
• Active middle-ear infection.
• The audiologist and/or surgeon will review the study protocol with the patient prior to having him/her sign the consent form. If the patient indicates he/she is unwilling or unable to comply with all investigational requirements, he/she will not be enrolled in the study.
• Using best clinical judgment based on professional interaction with the patient and his/her family, the managing audiologist and surgeon will determine if there are any disabling cognitive limitations that would prevent the patient from providing reliable data for this study.

• Adult male and female patients, 18-75 years of age at the time of enrollment.
• Diagnosis of probable or definitive Meniere's disease by AAOHNS 1995 criteria.
• Two of three active symptoms including vertigo or disequilibrium, fluctuating hearing loss, or tinnitus within the 3 months prior to study enrollment.
• Hearing loss of ≥ 30 dBHL at either 250, 500 or 1000 Hz.
• Voluntary consent to participate in the study.
• Male subjects that are willing to use condoms throughout the study period and 90-days following study completion even if not fertile.
• Females of childbearing potential should either be sexually inactive (abstinent) for 14 days prior to screening and throughout the study or be using one of the following acceptable birth control methods:
• IUD in place for at least 3 months prior to study; or
• Barrier method (condom or diaphragm) with spermicide for at least 14 days prior to screening through study completion; or
• Stable hormonal contraceptive for at least 3 months prior to study and through study completion; or
• Surgical sterilization (vasectomy) of partner at least 6 months prior to study enrollment.
• Females of non-childbearing potential should be surgically sterile (bilateral tubal ligation with surgery at least 6 months prior to study enrollment, hysterectomy, or bilateral oophorectomy at least 2 months prior to study) or be at least 1 year since last menses.
• Current use of or within 60 days prior to study IV ototoxic medications such as chemotherapy including cisplatin, carboplatinum, or oxaliplatin; aminoglycoside antibiotics including gentamicin, amikacin, tobramycin, kanamycin, or streptomycin; or loop diuretics including furosemide.
• History of otosclerosis or vestibular schwannoma.
• History of significant middle ear or inner ear surgery.
• Current conductive hearing loss, otitis media, or mixed hearing loss.
• Significant cardiovascular, pulmonary, hepatic, renal, hematologic, gastrointestinal, endocrine, immunologic, or psychiatric disease.
• Current use or within 30 days prior to study enrollment systemic steroids or drugs known to be strong inhibitors or inducers of cytochrome P450 enzymes.
• Hypersensitivity or idiosyncratic reaction to compounds related to ebselen or selenium.
• Female patients who are pregnant or breastfeeding.
• Participation in another interventional drug or device study within 30 days prior to study consent.

• Cystic fibrosis patients about to receive IV tobramycin for acute pulmonary exacerbation.
• Voluntarily consent to participate in the study.
• Females of childbearing potential should be using and committed to continue using one of the following acceptable birth control methods:
• Sexual abstinence (inactivity) for 14 days prior to screening through study completion; or IUD in place for at least 3 months prior to study through study completion; or Barrier method (condom or diaphragm) with spermicide for at least 14 days prior to screening through study completion; or Stable hormonal contraceptive for at least 3 months prior to study through study completion.
• Ability to perform all behavioral tests as indicated.
• Current use or within 60 days prior to study enrollment the following IV ototoxic medications: aminoglycoside antibiotics (gentamicin, tobramycin, amikacin, streptomycin); platinum-containing chemotherapies (cisplatin, carboplatin, oxaliplatin); or loop diuretic (furosemide).
• History of idiopathic sensorineural hearing loss, otosclerosis, or vestibular schwannoma.
• History of middle ear or inner ear surgery.
• Current conductive hearing loss or middle ear effusion.
• Significant cardiovascular, hepatic, renal, hematologic, endocrine, immunologic, or psychiatric disease.
• History of hypersensitivity or idiosyncratic reaction to compounds related to ebselen.
• Participation in another investigational drug or device study within 30 days prior to study enrollment.
• Female patients who are pregnant or breastfeeding.