Document Detail

Intraoperative round window recordings to acoustic stimuli from cochlear implant patients.
MedLine Citation:
PMID:  23047261     Owner:  NLM     Status:  MEDLINE    
HYPOTHESIS: Acoustically evoked neural and hair cell potentials can be measured from the round window (RW) intraoperatively in the general population of cochlear implant recipients.
BACKGROUND: Cochlear implant performance varies greatly among patients. Improved methods to assess and monitor functional hair cell and neural substrate before and during implantation could potentially aid in enhanced nontraumatic intracochlear electrode placement and subsequent improved outcomes.
METHODS: Subjects (1-80 yr) undergoing cochlear implantation were included. A monopolar probe was placed at the RW after surgical access was obtained. The cochlear microphonic (CM), summating potential (SP), compound action potential (CAP), and auditory nerve neurophonic (ANN) were recorded in response to tone bursts at frequencies of 0.25 to 4 kHz at various levels.
RESULTS: Measurable hair cell/neural potentials were detected to 1 or more frequencies in 23 of 25 subjects. The greatest proportion and magnitude of cochlear responses were to low frequencies (<1,000 Hz). At these low frequencies, the ANN, when present, contributed to the ongoing response at the stimulus frequency. In many subjects, the ANN was small or absent, whereas hair cell responses remained.
CONCLUSION: In cochlear implant recipients, acoustically evoked cochlear potentials are detectable even if hearing is extremely limited. Sensitive measures of cochlear and neural status can characterize the state of hair cell and neural function before implantation. Whether this information correlates with speech performance outcomes or can help in tailoring electrode type, placement or audiometric fitting, can be determined in future studies.
Baishakhi Choudhury; Douglas C Fitzpatrick; Craig A Buchman; Benjamin P Wei; Margaret T Dillon; Shuman He; Oliver F Adunka
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology     Volume:  33     ISSN:  1537-4505     ISO Abbreviation:  Otol. Neurotol.     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-11-15     Completed Date:  2013-04-29     Revised Date:  2013-12-04    
Medline Journal Info:
Nlm Unique ID:  100961504     Medline TA:  Otol Neurotol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1507-15     Citation Subset:  IM    
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MeSH Terms
Acoustic Stimulation / methods*
Action Potentials / physiology
Aged, 80 and over
Audiometry, Evoked Response / methods*
Auditory Threshold / physiology
Child, Preschool
Cochlear Implantation*
Cochlear Microphonic Potentials
Cochlear Nerve / physiology
Data Interpretation, Statistical
Evoked Potentials, Auditory / physiology
Hair Cells, Auditory / physiology
Hearing Loss / etiology,  surgery,  therapy
Middle Aged
Monitoring, Intraoperative / methods*
Neurons / physiology
Round Window, Ear / physiology*
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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