Inclusion Criteria:
1. Evidence of a sensorineural hearing loss
* Unilateral or bilateral in configuration
* Symmetrical or asymmetrical configuration
* Sudden or progressive in presentation
* Moderate to profound in degree (40-90 Decibels (dB) in at least one ear
2. Normally shaped cochlea, as determined by MRI
3. The loss must be considered:
* Acquired
* Unknown with a negative genetic test.
4. Fitted for hearing aids no later than six months post detection of loss.
5. Enrollment in a parent/child intervention program
6. Age 6 weeks - 6 years old at time of infusion with less than 18 months of hearing loss at the time of cord blood infusion.
7. Ability of the child and caregiver to travel to Orlando, and stay for at least 4 days, and to return for all follow-up visits.
Exclusion Criteria
1. Inability to obtain all pertinent medical records:
* (pertinent physician notes, speech language pathology notes, laboratory findings, test results and imaging studies-must be sent to the research team at least prior to the subject arriving at the study location for preliminary screening and eligibility assessment, preferably14 days before the scheduled hUBC treatment.)
2. Known history of:
* Recently treated infection less than 2 weeks before infusion.
* Renal disease of altered renal function as defined by serum creatinine \> 1.5 mg/dl at admission.
* Hepatic disease or altered liver function as defined by SGPT \> 150 U/L, and or T. Bilirubin \> 1.3 mg/dL
* Malignancy
* Immunosuppression as defined by WBC \< 3,000 at admission
* Human Immunodeficiency Virus (HIV)
* Hepatitis B
* Hepatitis C
* Evidence of an extensive stroke (\> 100ml lesion)
* Pneumonia, or chronic lung disease requiring oxygen
* Genetic syndromic sensorineural hearing loss
3. hUBC sample contamination
4. Banked cord cells totaling less than 6x106 mononuclear cells/kilogram body weight.
5. Evidence of the following maternal infections during the pregnancy (Hepatitis A, Hepatitis B, Hepatitis C, HIV 1, HIV 2, Human T-lymphotropic Virus (HTLV) 1, HTLV 2 (CMV and Syphilis can be included in the study)
6. participation in a concurrent intervention study
7. Unwillingness or inability to stay for 4 days following hUBC infusion (should problems arise following the infusion) and to return for the one month, six month and one year follow-up visits.
8. Presence of a cochlear implantation device
9. Evidence of a genetic syndrome
10. Evidence of conductive hearing loss
11. Documented recurrent middle ear infections which are frequent (\>5 per year)
12. Otitis media at the time of examination
13. Sensorineural loss is mild
14. Over 18 months from identification of hearing loss at time of infusion
