SPI-1005 in Adults Receiving Cochlear Implant

Inclusion Criteria: * Adults who are ≥18 years of age at time of consent. * Post-lingual, bilateral, severe to profound sensorineural hearing loss scheduled to receive a long electrode array (FLEX26 or greater) from MED-EL Cochlear Implant Systems into one ear. * Air conduction thresholds (decibel hearing loss, dB HL) at baseline in the ear scheduled to receive the cochlear implant: * ≥40 and ≤70 dB HL at 125, 250, and 500 Hz; AND * ≥80 dB HL at 2000 through 8000 Hz. * Willing and able to provide informed consent and to perform all behavioral tests as specified per-protocol, including pre-specified reproductive requirements. Exclusion Criteria: * Current, or within 60 days prior to study enrollment, use of IV ototoxic medications such as chemotherapy including cisplatin, carboplatin, or oxaliplatin; aminoglycoside antibiotics including gentamicin, amikacin, tobramycin, kanamycin, or streptomycin; or loop diuretics including furosemide. * Participation in another investigational drug or device study within 90 days prior to study enrollment. * Female patients who are pregnant or breastfeeding. * Air conduction thresholds at baseline in the ear scheduled to receive the cochlear implant with any No Response at 125 through 8000 Hz.