2011 — 2012 |
Cheung, Steven Wan |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Auditory Thalamic Implant @ University of California, San Francisco
DESCRIPTION (provided by applicant): Deaf neurofibromatosis type 2 (NF2) patients have limited rehabilitation choices. Extracranial cochlear implants are inappropriate for NF2 patients without intact auditory nerves, a consequence of bilateral vestibular schwannomas. Intracranial cochlear nucleus brainstem and inferior colliculus midbrain implants are two possible treatment options. Those devices provide encouraging but relatively modest benefits compared to cochlear implant hearing outcomes in non-NF2 patients. The current conceptual framework for deafness rehabilitation in NF2 patients is implantation of intracranial devices to auditory structures accessible via infratentorial posterior fossa craniotomy under general anesthesia. Direct visual identification of the target auditory nucleus for implant placement is the dominant surgical technique. However, reliable placement and stable positioning of electrodes have been major challenges. An alternate strategy to possibly improve therapeutic outcomes is device implantation of the ventral medial geniculate body via supratentorial burr hole craniotomy under local anesthesia. Adaptation of established deep brain stimulation and computer assisted surgical navigation technologies to target the auditory thalamus would supplant current surgical practices. This project proposes taking initial step towards the development of a clinically deployable auditory thalamic implant. Animal studies are planned to measure electrically driven ventral medial geniculate body thalamocortical transformations that would serve as design parameters to engineer a suitable brain probe and speech processor. PUBLIC HEALTH RELEVANCE: Deaf patients without intact auditory nerves, such as those afflicted by neurofibromatosis type 2, have very limited rehabilitation options. Research to develop a better hearing device is necessary to meet communication needs of this underserved population. Knowledge derived from this project may also help many other hearing impaired individuals.
|
0.958 |
2021 |
Cheung, Steven Wan Nagarajan, Srikantan S. (co-PI) [⬀] |
R56Activity Code Description: To provide limited interim research support based on the merit of a pending R01 application while applicant gathers additional data to revise a new or competing renewal application. This grant will underwrite highly meritorious applications that if given the opportunity to revise their application could meet IC recommended standards and would be missed opportunities if not funded. Interim funded ends when the applicant succeeds in obtaining an R01 or other competing award built on the R56 grant. These awards are not renewable. |
Brain Plasticity and Clinical Consequences of Adult-Onset Asymmetric Hearing Loss @ University of California, San Francisco
PROJECT SUMMARY Permanent sensorineural asymmetric hearing loss (AHL) disrupts extraction of interaural information for binaural processing. Using a cutoff of at least 15 dB interaural difference as definition of AHL, prevalence estimates vary widely, from 1% to 50%. Among cohorts with occupational noise exposure, AHL prevalence ranges from 15%- 49%. Critical clinical consequences include difficulty with sound target identification in noisy environments and degradation of spatial hearing. Beyond those impairments, the aidable poorer ear in AHL is at risk for accelerated decline and often burdened by tinnitus. There is a wide gap in our understanding of the relationship between central nervous system changes along the continuum of AHL magnitudes, audiological and psychoacoustical outcomes, and tinnitus perception. Closing this knowledge gap would be the first step to advance diagnostic tools and inspire innovative treatments for AHL. Informed by anchoring neuroimaging and audiological data from normal hearing and single-sided deafness, the most extreme form of AHL, we propose to close this knowledge gap. A comprehensive study on the clinical consequences of AHL should address hearing performance under adverse conditions, spatial hearing, and tinnitus outcomes, and their central neural correlates. We propose a longitudinal within-subject neuroimaging features and clinical assessments study of AHL before and after treatment by amplification. We will use resting-state magnetoencephalographic imaging (RS-MEGI) and functional magnetic resonance imaging (RS-fMRI), task-based MEGI, and diffusion MRI to examine temporal, functional and structural features, and audiological and psychoacoustical tests to evaluate hearing performance and tinnitus outcomes. This observational study will collect data from participants who will be treated by routine amplification with individualized tinnitus sound therapies, as required, for AHL. We will evaluate test-retest reliability of neuroimaging features, and assess neuroimaging features, hearing performance, and tinnitus outcomes at baseline and at months 3, 6 and 12 following treatment. The specific aims of this research are to examine: 1) AHL clinical outcomes, 2) AHL auditory interhemispheric temporal organization using MEGI, and 3) AHL whole brain functional and structural neuroimaging features using resting-state MEGI and fMRI (functional), task-based MEGI (functional), and diffusion MRI (structural).
|
0.958 |