Vijayalakshmi Easwar1,2, Jen Birstler3, Adrienne Harrison2,4, Susan Scollie2,5, David Purcell2,5. 1. Department of Communication Sciences and Disorders & Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA. 2. National Centre for Audiology, Western University, London, Ontario, Canada. 3. Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin, USA. 4. Health and Rehabilitation Sciences, Western University, London, Ontario, Canada. 5. School of Communication Sciences and Disorders, Western University, London, Ontario, Canada.
Abstract
OBJECTIVES: To evaluate sensation level (SL)-dependent characteristics of envelope following responses (EFRs) elicited by band-limited speech dominant in low, mid, and high frequencies. DESIGN: In 21 young normal hearing adults, EFRs were elicited by 8 male-spoken speech stimuli-the first formant, and second and higher formants of /u/, /a/ and /i/, and modulated fricatives, /∫/ and /s/. Stimulus SL was computed from behaviorally measured thresholds. RESULTS: At 30 dB SL, the amplitude and phase coherence of fricative-elicited EFRs were ~1.5 to 2 times higher than all vowel-elicited EFRs, whereas fewer and smaller differences were found among vowel-elicited EFRs. For all stimuli, EFR amplitude and phase coherence increased by roughly 50% for every 10 dB increase in SL between ~0 and 50 dB. CONCLUSIONS: Stimulus and frequency dependency in EFRs exist despite accounting for differences in audibility of speech sounds. The growth rate of EFR characteristics with SL is independent of stimulus and its frequency.
OBJECTIVES: To evaluate sensation level (SL)-dependent characteristics of envelope following responses (EFRs) elicited by band-limited speech dominant in low, mid, and high frequencies. DESIGN: In 21 young normal hearing adults, EFRs were elicited by 8 male-spoken speech stimuli-the first formant, and second and higher formants of /u/, /a/ and /i/, and modulated fricatives, /∫/ and /s/. Stimulus SL was computed from behaviorally measured thresholds. RESULTS: At 30 dB SL, the amplitude and phase coherence of fricative-elicited EFRs were ~1.5 to 2 times higher than all vowel-elicited EFRs, whereas fewer and smaller differences were found among vowel-elicited EFRs. For all stimuli, EFR amplitude and phase coherence increased by roughly 50% for every 10 dB increase in SL between ~0 and 50 dB. CONCLUSIONS: Stimulus and frequency dependency in EFRs exist despite accounting for differences in audibility of speech sounds. The growth rate of EFR characteristics with SL is independent of stimulus and its frequency.
Authors: Andrew Dimitrijevic; M Sasha John; Patricia Van Roon; David W Purcell; Julija Adamonis; Jodi Ostroff; Julian M Nedzelski; Terence W Picton Journal: J Am Acad Audiol Date: 2002-04 Impact factor: 1.664