Cochlear Implant Speech in Noise Processing

Cochlear Implant subjects (enrollment is planned at N=120) - Inclusion criteria:

1. Between 18 and 99 years of age.
2. Have a cochlear implant activated for more than one year.
3. Eligible for research under the Iowa Cochlear Implant Project VIII.
4. Ability to understand and willingness to sign a written informed consent document.
5. Severe hearing loss after age 16.

Normal Hearing subjects (enrollment is planned at N=30) - Inclusion criteria:

1. Between 18 and 99 years of age.
2. Have age typical hearing.
3. Eligible for research under the Iowa Cochlear Implant Project VIII.
4. Ability to understand and willingness to sign a written informed consent document.

Exclusion criteria (all groups):

1. Medical history includes seizure disorder, head injury, neurologic, metabolic, cardiovascular disease, or previous cerebrovascular event (unless approved by PI).
2. Female self-reporting pregnancy. A urine pregnancy test will be performed prior to injection of the radiopharmaceutical.
3. Currently taking medications which may affect cerebral blood flow (e.g., papaverine, ginkgo biloba, acetazolamide).
4. Uncontrolled intercurrent illness that would limit compliance with study requirements per investigator.