Influence of Relative Amplitude and Presentation Level on Perception of the /p/ – /t/ Stop Consonant Contrast by Normal and Impaired Listeners

2019 ◽  
pp. 475-486
Author(s):  
Mark S. Hedrick ◽  
Walt Jesteadt
2001 ◽  
Vol 44 (5) ◽  
pp. 964-974 ◽  
Author(s):  
Mark Hedrick ◽  
Mary Sue Younger

The current study explored the changes in weighting of relative amplitude and formant transition cues that may be caused by a K-amp circuit. Twelve listeners with normal hearing and 3 listeners with sensorineural hearing loss labeled the stop consonant place of articulation of synthetic consonant-vowel stimuli. Within the stimuli, two acoustic cues were varied: the frequency of the onset of the second and third formant (F2/F3) transitions and the relative amplitude between the consonant burst and the following vowel in the fourth and fifth formant (F4/ F5) frequency region. The variation in the two cues ranged from values appropriate for a voiceless labial stop consonant to a voiceless alveolar stop consonant. The listeners labeled both the unaided stimuli and the stimuli recorded through a hearing aid with a K-amp circuit. An analysis of variance (ANOVA) model was used to calculate the perceptual weight given each cue. Data from listeners with normal hearing show a change in relative weighting of cues between aided and unaided stimuli. Pilot data from the listeners with hearing loss show a more varied pattern, with more weight placed on relative amplitude. These results suggest that calculation of perceptual weights using an ANOVA model may be worthwhile in future studies examining the relationship between acoustic information presented by a hearing aid and the subsequent perception by the listener with hearing loss.


1997 ◽  
Vol 40 (6) ◽  
pp. 1445-1457 ◽  
Author(s):  
Mark S. Hedrick ◽  
Arlene Earley Carney

Previous studies have shown that manipulation of a particular frequency region of the consonantal portion of a syllable relative to the amplitude of the same frequency region in an adjacent vowel influences the perception of place of articulation. This manipulation has been called the relative amplitude cue. Earlier studies have examined the effect of relative amplitude and formant transition manipulations upon labeling place of articulation for fricatives and stop consonants in listeners with normal hearing. The current study sought to determine if (a) the relative amplitude cue is used by adult listeners wearing a cochlear implant to label place of articulation, and (b) adult listeners wearing a cochlear implant integrated the relative amplitude and formant transition information differently than listeners with normal hearing. Sixteen listeners participated in the study, 12 with normal hearing and 4 postlingually deafened adults wearing the Nucleus 22 electrode Mini Speech Processor implant with the multipeak processing strategy. The stimuli used were synthetic consonant-vowel (CV) syllables in which relative amplitude and formant transitions were manipulated. The two speech contrasts examined were the voiceless fricative contrast /s/-/∫/and the voiceless stop consonant contrast /p/-/t/. For each contrast, listeners were asked to label the consonant sound in the syllable from the two response alternatives. Results showed that (a) listeners wearing this implant could use relative amplitude to consistently label place of articulation, and (b) listeners with normal hearing integrated the relative amplitude and formant transition information more than listeners wearing a cochlear implant, who weighted the relative amplitude information as much as 13 times that of the transition information.


1997 ◽  
Vol 40 (4) ◽  
pp. 925-938 ◽  
Author(s):  
Mark Hedrick

Previous studies have shown that manipulation of frication amplitude relative to vowel amplitude in the third formant frequency region affects labeling of place of articulation for the fricative contrast /s/- /∫/(Hedrick & Ohde, 1993; Stevens, 1985). The current study examined the influence of this relative amplitude manipulation in conjunction with presentation level, frication duration, and formant transition cues for labeling fricative place of articulation by listeners with normal hearing and listeners with sensorineural hearing loss. Synthetic consonant-vowel (CV) stimuli were used in which the amplitude of the frication relative to vowel onset amplitude in the third formant frequency region was manipulated across a 20 dB range. The listeners with hearing loss appeared to have more difficulty using the formant transition component than the relative amplitude component for the labeling task than most listeners with normal hearing. A second experiment was performed with the same stimuli in which the listeners were given one additional labeling response alternative, the affricate /t∫/. Results from this experiment showed that listeners with normal hearing gave more /t∫/labels as relative amplitude and presentation level increased and frication duration decreased. There was a significant difference between the two groups in the number of affricate responses, as listeners with hearing loss gave fewer /t∫/labels.


2002 ◽  
Vol 13 (03) ◽  
pp. 154-159 ◽  
Author(s):  
Patrick N. Plyler ◽  
Mark S. Hedrick

The purpose of the present study was to determine whether varying the presentation level of stop consonant stimuli resulted in similar phonetic boundary shifts for listeners with normal and impaired hearing. Sixteen normal-hearing and 16 hearing-impaired listeners categorized synthetic speech stimuli as /b/, /d/, or /g/. The onset frequency of F2 varied from 900 to 2300 Hz (100-Hz steps), and the presentation level varied from 92 to 62 dB SPL (10-dB steps) for each stimulus presentation. Hearing-impaired listeners had significantly more missing boundary values than normal-hearing listeners; however, the correlation between the number of missing boundary values and hearing sensitivity was not significant. Comparison of boundary shift with level demonstrated that hearing-impaired listeners had a smaller boundary shift with increasing level than normal-hearing listeners. The amount of boundary shift was not correlated with audibility. The results of the current study suggest that increasing the presentation level of a signal does not result in performance similar to that of listeners with normal hearing.


1990 ◽  
Vol 71 (1) ◽  
pp. 275-280
Author(s):  
Linda I. Shuster

The two experiments described in this paper were designed to investigate further the phenomenon called motor-motor adaptation. In the first investigation, subjects were adapted while noise was presented through headphones, which prevented them from hearing themselves. In the second experiment, subjects repeated an isolated vowel, as well as a consonant-vowel syllable which contained a stop consonant. The findings indicated that motor-motor adaptation is not a product of perceptual adaptation, and it is not a result of subjects producing longer voice onset times after adaptation to a voiced consonant rather than shorter voice onset times after adaptation to a voiceless consonant.


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