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Study of Nucleus 24 Auditory Brainstem Implant (ABI) in Adult Non-Neurofibromatosis Type 2 Subjects

Phase 4
18 Years
Open (Enrolling)
Bilateral Hearing Loss for Causes Other Than Tumors

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Trial Information

Study of Nucleus 24 Auditory Brainstem Implant (ABI) in Adult Non-Neurofibromatosis Type 2 Subjects

The goal of this MEEI Auditory Brainstem Implant (ABI) research study is to find new ways to
improve hearing in patients who are deaf and cannot receive a cochlear implant. The ABI is
a surgically placed bionic implant that converts sounds into electrical signals that are
directly transmitted to the cochlear nucleus, the first auditory center of the brain. For
many years, ABIs have improved the hearing of patients who are deaf due to brain tumors
associated with a genetic syndrome called Neurofibromatosis Type 2 (NF2). However, a number
of recent studies suggest that deaf patients who do not have NF2 and are not eligible for a
cochlear implant may also benefit from placement of an ABI. These preliminary studies
suggest that these non-NF2 or "nontumor" patients may actually have better outcomes after
ABI surgery than patients suffering from NF2. Patients who do not have NF2 and are deaf due
to damage to the hearing nerves or inner ears from infection, disease or injury are not
cochlear implant candidates and there are no other options to improve hearing in these cases
except for the ABI. Thus, the purpose of our study is to carefully analyze whether ABI
surgery improves the hearing and quality of life of non-NF2 patients based on subjective and
objective measures of their hearing before and after ABI surgery. In particular, we plan to
study ABI outcomes in non-NF2 patients, characterize the parameters used on their devices,
and determine the safety profile of ABIs in these patients.

Inclusion Criteria:

- 18 years of age or older

- English as the primary language

- Medically and psychologically suitable

- Willing to receive/have received meningitis / pneumoccal vaccinations

- Able to comply with study requirements, including travel to the investigational site

- Cochlear or retrocochlear anomaly/pathology that interferes with transmission of
auditory information from the cochleae to the brainstem, resulting in severe to
profound bilateral deafness (thresholds of 90 dB or worse in both ears on pure tone
audiometry ranging from 250 to 2,000 Hz and speech recognition scores ≤ 30% in both
ears). All subjects will undergo bone conduction audiometry and tympanometry to
confirm sensorineural hearing loss and rule out potential middle ear disorders.

- Conditions that cannot be otherwise treated, with conventional hearing aids or
cochlear implants. If CI were previously used, subjects will have had a failed
response, defined as ≤ 30% speech recognition and patient perception of
inadequate benefit to continue using the device.

- Expected subjects include those with these diagnoses:

- Bilaterally severe/completely ossified cochleae

- Bilateral cochlear malformations leading to poor CI outcomes

- Bilateral temporal bone fractures, where the VIIIth cranial nerves have
been disrupted

- Bilateral cochlear nerve agenesis

- Not a CI candidate based on above listed pathology, intolerable adverse
effects with CI (e.g. stimulation of the facial nerve), or Evoked Auditory
Potential testing predictive of a poor response

Exclusion Criteria:

- Anomalies/pathology involving the brainstem or cortex

- Retrocochlear pathology resulting from NF2 or other types of cranial nerve or
brainstem neoplasm

- Co-existing medical conditions that require irradiation of the brainstem or auditory

- Medical or psychological conditions that serve as contraindication to surgery

- Additional handicaps that would prevent or limit participation in evaluations

- Unrealistic patient or family expectations regarding the benefits, risks, and
limitations inherent to the procedure and the prosthetic device

- Pregnant women

Type of Study:


Study Design:

Endpoint Classification: Safety Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment

Outcome Measure:

Peri-operative and post-operative complications

Outcome Description:

We will track any major and minor complications intra-operatively and post-operatively in all study participants.

Outcome Time Frame:

5 years from date of surgery

Safety Issue:


Principal Investigator

Daniel J Lee, MD, FACS

Investigator Role:

Principal Investigator

Investigator Affiliation:



United States: Food and Drug Administration

Study ID:

MEEI HSC 12-061



Start Date:

November 2012

Completion Date:

November 2022

Related Keywords:

  • Bilateral Hearing Loss for Causes Other Than Tumors
  • Auditory Brainstem Implant
  • ABI
  • Nucleus 24
  • Deafness
  • Hearing loss
  • Non-tumor
  • Non-NF2
  • Hearing Loss
  • Deafness
  • Hearing Loss, Bilateral



Massachusetts Eye and Ear InfirmaryBoston, Massachusetts  02114-3096