Document Detail


Auditory steady-state responses to exponential modulation envelopes.
MedLine Citation:
PMID:  11951847     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: This study examined the steady-state responses evoked by tones modulated with exponential envelopes. The hypothesis was that stimuli with envelopes containing more rapid changes would evoke larger responses. DESIGN: Multiple auditory steady-state responses were recorded simultaneously to eight tonal stimuli, four in each ear. The carrier frequencies of the stimuli ranged from 500 to 6000 Hz and the modulation rates were between 75 and 95 Hz. The modulation envelopes were based on functions using sin' where N was 1, 2, 3, or 4. Setting N to 1 produced the traditional sinusoidal modulation. RESULTS: Exponential envelopes with N greater than 1 produced larger steady-state responses than a sinusoidal envelope. For amplitude-modulation (AM), exponential envelopes increased response amplitudes by 21% at 55 dB pSPL, and by 29% at 35 dB pSPL. The increases were smaller for carrier frequencies of 1500 to 2000 Hz than for lower and higher carrier frequencies. Latencies calculated from phase data increased significantly with increasing N. This was likely caused by the point of maximal envelope-slope shifting later in time as N increased. For frequency modulation (FM), the steady-state responses did not significantly change with changes in the power of the exponential envelopes. CONCLUSIONS: When tones are amplitude-modulated with exponential envelopes based on sin(N), the amplitude and latency of the steady-state response increased significantly with increasing N. Using exponential envelopes with N greater than 1 should considerably shorten the time needed for responses to become significant when using steady-state responses in objective audiometry.
Authors:
M Sasha John; Andrew Dimitrijevic; Terence W Picton
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Ear and hearing     Volume:  23     ISSN:  0196-0202     ISO Abbreviation:  Ear Hear     Publication Date:  2002 Apr 
Date Detail:
Created Date:  2002-04-15     Completed Date:  2002-10-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8005585     Medline TA:  Ear Hear     Country:  United States    
Other Details:
Languages:  eng     Pagination:  106-17     Citation Subset:  IM    
Affiliation:
Rotman Research Institute, Baycrest Centre for Geriatric Care, University of Toronto, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Adult
Auditory Perception / physiology*
Evoked Potentials, Auditory, Brain Stem / physiology*
Female
Humans
Male
Models, Biological

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


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