TY - JOUR
T1 - Vowel identification by amplitude and phase contrast
AU - Molis, Michelle R.
AU - Diedesch, Anna
AU - Gallun, Frederick
AU - Leek, Marjorie R.
N1 - Funding Information:
This research was supported by grant no. R01 DC 00626 [PI: Leek] from the NIDCD. Diedesch was supported by T35 DC008764 [PI: Leek], also from the NIDCD. Support was also provided by the Department of Veterans Affairs Rehabilitation Research &Development Service [Career Development grants C6116W (Molis) and C4963W (Gallun), and Senior Research Career Scientist award C4042L (Leek)]. The work was supported with resources and the use of facilities at the Portland VA Medical Center. The contents of this article do not represent the views of the Department of Veterans Affairs or the United States Government.
PY - 2013/2
Y1 - 2013/2
N2 - Vowel identification is largely dependent on listeners' access to the frequency of two or three peaks in the amplitude spectrum. Earlier work has demonstrated that, whereas normal-hearing listeners can identify harmonic complexes with vowel-like spectral shapes even with very little amplitude contrast between "formant" components and remaining harmonic components, listeners with hearing loss require greater amplitude differences. This is likely the result of the poor frequency resolution that often accompanies hearing loss. Here, we describe an additional acoustic dimension for emphasizing formant versus non-formant harmonics that may supplement amplitude contrast information. The purpose of this study was to determine whether listeners were able to identify "vowel-like" sounds using temporal (component phase) contrast, which may be less affected by cochlear loss than spectral cues, and whether overall identification improves when congruent temporal and spectral information are provided together. Five normal-hearing and five hearing-impaired listeners identified three vowels over many presentations. Harmonics representing formant peaks were varied in amplitude, phase, or a combination of both. In addition to requiring less amplitude contrast, normal-hearing listeners could accurately identify the sounds with less phase contrast than required by people with hearing loss. However, both normal-hearing and hearing-impaired groups demonstrated the ability to identify vowel-like sounds based solely on component phase shifts, with no amplitude contrast information, and they also showed improved performance when congruent phase and amplitude cues were combined. For nearly all listeners, the combination of spectral and temporal information improved identification in comparison to either dimension alone.
AB - Vowel identification is largely dependent on listeners' access to the frequency of two or three peaks in the amplitude spectrum. Earlier work has demonstrated that, whereas normal-hearing listeners can identify harmonic complexes with vowel-like spectral shapes even with very little amplitude contrast between "formant" components and remaining harmonic components, listeners with hearing loss require greater amplitude differences. This is likely the result of the poor frequency resolution that often accompanies hearing loss. Here, we describe an additional acoustic dimension for emphasizing formant versus non-formant harmonics that may supplement amplitude contrast information. The purpose of this study was to determine whether listeners were able to identify "vowel-like" sounds using temporal (component phase) contrast, which may be less affected by cochlear loss than spectral cues, and whether overall identification improves when congruent temporal and spectral information are provided together. Five normal-hearing and five hearing-impaired listeners identified three vowels over many presentations. Harmonics representing formant peaks were varied in amplitude, phase, or a combination of both. In addition to requiring less amplitude contrast, normal-hearing listeners could accurately identify the sounds with less phase contrast than required by people with hearing loss. However, both normal-hearing and hearing-impaired groups demonstrated the ability to identify vowel-like sounds based solely on component phase shifts, with no amplitude contrast information, and they also showed improved performance when congruent phase and amplitude cues were combined. For nearly all listeners, the combination of spectral and temporal information improved identification in comparison to either dimension alone.
KW - formants
KW - frequency selectivity
KW - hearing impairment
KW - phase
KW - spectral contrast
KW - vowel identification
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U2 - 10.1007/s10162-012-0352-1
DO - 10.1007/s10162-012-0352-1
M3 - Article
C2 - 23007720
AN - SCOPUS:84872421257
SN - 1525-3961
VL - 14
SP - 125
EP - 137
JO - JARO - Journal of the Association for Research in Otolaryngology
JF - JARO - Journal of the Association for Research in Otolaryngology
IS - 1
ER -