Document Detail


Evaluation of round window stimulation using the floating mass transducer by intracochlear sound pressure measurements in human temporal bones.
MedLine Citation:
PMID:  19841600     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
HYPOTHESIS: Round window (RW) stimulation with a floating mass transducer (FMT) can be studied experimentally and optimized to enhance auditory transduction.
BACKGROUND: The FMT (MED-EL Vibrant Soundbridge) has been recently implanted in patients with refractory conductive or mixed hearing loss to stimulate the RW with varying degrees of success. The mechanics of RW stimulation with the FMT have not been studied in a systematic manner.
METHODS: In cadaveric human temporal bones, measurements of stapes velocity with laser vibrometry in response to FMT-RW stimulation were used to optimize FMT insertion. The effect of RW stimulation on hearing was estimated using simultaneous measurements of intracochlear pressures in both perilymphatic scalae with micro-optical pressure transducers. This enabled calculation of the differential pressure across the cochlear partition, which is directly tied to auditory transduction.
RESULTS: The best coupling between the FMT and RW was achieved with a piece of fascia placed between the RW and the FMT, and by "bracing" the free end of the FMT against the hypotympanic wall with dental impression material. FMT-RW stimulation provided differential pressures comparable with sound-induced oval window stimulation greater than 1 kHz. However, less than 1 kHz, the FMT was less capable.
CONCLUSION: Measurements of stapes velocity and intracochlear sound pressures in scala vestibuli and scala tympani enabled experimental evaluation of FMT stimulation of the RW. The efficacy of FMT-RW coupling was influenced significantly by technical and surgical factors, which can be optimized. This temporal bone preparation also lays the foundation for future studies to investigate multiple issues of relevance to both basic and clinical science such as RW stimulation in stapes fixation, nonaerated middle ears, and third-window lesions, and to answer basic questions regarding bone conduction.
Authors:
Hideko Heidi Nakajima; Wei Dong; Elizabeth S Olson; John J Rosowski; Michael E Ravicz; Saumil N Merchant
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology     Volume:  31     ISSN:  1537-4505     ISO Abbreviation:  Otol. Neurotol.     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-04-14     Completed Date:  2010-07-09     Revised Date:  2014-09-13    
Medline Journal Info:
Nlm Unique ID:  100961504     Medline TA:  Otol Neurotol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  506-11     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Acoustic Stimulation
Bone Conduction / physiology
Ear, Middle / physiology*,  surgery
Humans
Round Window, Ear / physiology*,  surgery
Temporal Bone / surgery*
Transducers
Grant Support
ID/Acronym/Agency:
R01 DC003130/DC/NIDCD NIH HHS; R01 DC004798/DC/NIDCD NIH HHS; R01 DC004798-09/DC/NIDCD NIH HHS; R01 DC004798-09S1/DC/NIDCD NIH HHS; R01 DC04798/DC/NIDCD NIH HHS; T32 DC00020/DC/NIDCD NIH HHS
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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