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Effect of stimuli, transducers and gender on acoustic change complex.

Shetty HN, Puttabasappa M - Audiol Res (2012)

Bottom Line: There was no significant difference in amplitude of ACC between the stimuli.Among the transducers, there was no significant difference in latency and amplitude of ACC, for both /sa/ and /si/ stimuli.Female participants showed earlier latency for 2N1 and larger amplitude of N1 and 2P2 than male participants, which was significant.

View Article: PubMed Central - PubMed

Affiliation: All India Institute of Speech and Hearing, India.

ABSTRACT
The objective of this study was to investigate the effect of stimuli, transducers and gender on the latency and amplitude of acoustic change complex (ACC). ACC is a multiple overlapping P1-N1-P2 complex reflecting acoustic changes across the entire stimulus. Fifteen males and 15 females, in the age range of 18 to 25 (mean=21.67) years, having normal hearing participated in the study. The ACC was recorded using the vertical montage. The naturally produced stimuli /sa/ and /si/ were presented through the insert earphone/loud speaker to record the ACC. The ACC obtained from different stimuli presented through different transducers from male/female participants were analyzed using mixed analysis of variance. Dependent t-test and independent t-test were performed when indicated. There was a significant difference in latency of 2N1 at the transition, with latency for /sa/ being earlier; but not at the onset portions of ACC. There was no significant difference in amplitude of ACC between the stimuli. Among the transducers, there was no significant difference in latency and amplitude of ACC, for both /sa/ and /si/ stimuli. Female participants showed earlier latency for 2N1 and larger amplitude of N1 and 2P2 than male participants, which was significant. ACC provides important insight in detecting the subtle spectral changes in each stimulus. Among the transducers, no difference in ACC was noted as the spectra of stimuli delivered were within the frequency response of the transducers. The earlier 2N1 latency and larger N1 and 2P2 amplitudes noticed in female participants could be due to smaller head circumference. The findings of this study will be useful in determining the capacity of the auditory pathway in detecting subtle spectral changes in the stimulus at the level of the auditory cortex.

No MeSH data available.


The latency and amplitude of acoustic change complex (ACC) for /sa/ and /si/ presented through insert earphone and loudspeaker. The latency of onset and transition of ACC were earlier for insert earphone than loudspeaker for each stimulus. Amplitude of transition portion of ACC was larger for loudspeaker than insert earphone for each stimulus. In onset portion of ACC, the N1 mean amplitude was larger for /sa/ stimulus presented through insert earphone than loudspeaker.
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Figure 6: The latency and amplitude of acoustic change complex (ACC) for /sa/ and /si/ presented through insert earphone and loudspeaker. The latency of onset and transition of ACC were earlier for insert earphone than loudspeaker for each stimulus. Amplitude of transition portion of ACC was larger for loudspeaker than insert earphone for each stimulus. In onset portion of ACC, the N1 mean amplitude was larger for /sa/ stimulus presented through insert earphone than loudspeaker.

Mentions: The grand average of ACC waveforms obtained for /sa/ and /si/ stimulus when presented through insert earphone and loudspeaker are depicted in Figures 5 and 6. From Table 1, it was found that the mean latencies of onset of consonant (N1-P2) and transition from frication to onset of vowel (2N1-2P2) were shorter for /sa/ than /si/ stimulus, presented through either transducer. Further, the mean latencies of N1-P2 and 2N1- 2P2 were shorter for insert earphone than loudspeaker for both the stimuli. A two-way mixed ANOVA was performed to determine the effect of stimuli and transducers on the latency of different components of ACC. The interaction and main effects of mixed ANOVAs conducted on latency of each component of ACC was reported in Table 3. The result revealed no significant interaction effects in any of the components of ACC. However, it was found that there was a significant main effect of the stimuli on the latency of 2N1 [F (1, 26)=36.08, P<0.00] and not in other components of ACC. Further, on dependent t-test revealed that the latency of 2N1 was significantly shorter for /sa/ compared to /si/ for insert earphone for both male [t (14)=4.92, P<0.00] and female participants [t (14)=3.46, P<0.00]. A similar trend was noticed for loudspeaker in both male [t (14)=3.92, P<0.00] and female [t (14)=4.17, P<0.00] participants.


Effect of stimuli, transducers and gender on acoustic change complex.

Shetty HN, Puttabasappa M - Audiol Res (2012)

The latency and amplitude of acoustic change complex (ACC) for /sa/ and /si/ presented through insert earphone and loudspeaker. The latency of onset and transition of ACC were earlier for insert earphone than loudspeaker for each stimulus. Amplitude of transition portion of ACC was larger for loudspeaker than insert earphone for each stimulus. In onset portion of ACC, the N1 mean amplitude was larger for /sa/ stimulus presented through insert earphone than loudspeaker.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 6: The latency and amplitude of acoustic change complex (ACC) for /sa/ and /si/ presented through insert earphone and loudspeaker. The latency of onset and transition of ACC were earlier for insert earphone than loudspeaker for each stimulus. Amplitude of transition portion of ACC was larger for loudspeaker than insert earphone for each stimulus. In onset portion of ACC, the N1 mean amplitude was larger for /sa/ stimulus presented through insert earphone than loudspeaker.
Mentions: The grand average of ACC waveforms obtained for /sa/ and /si/ stimulus when presented through insert earphone and loudspeaker are depicted in Figures 5 and 6. From Table 1, it was found that the mean latencies of onset of consonant (N1-P2) and transition from frication to onset of vowel (2N1-2P2) were shorter for /sa/ than /si/ stimulus, presented through either transducer. Further, the mean latencies of N1-P2 and 2N1- 2P2 were shorter for insert earphone than loudspeaker for both the stimuli. A two-way mixed ANOVA was performed to determine the effect of stimuli and transducers on the latency of different components of ACC. The interaction and main effects of mixed ANOVAs conducted on latency of each component of ACC was reported in Table 3. The result revealed no significant interaction effects in any of the components of ACC. However, it was found that there was a significant main effect of the stimuli on the latency of 2N1 [F (1, 26)=36.08, P<0.00] and not in other components of ACC. Further, on dependent t-test revealed that the latency of 2N1 was significantly shorter for /sa/ compared to /si/ for insert earphone for both male [t (14)=4.92, P<0.00] and female participants [t (14)=3.46, P<0.00]. A similar trend was noticed for loudspeaker in both male [t (14)=3.92, P<0.00] and female [t (14)=4.17, P<0.00] participants.

Bottom Line: There was no significant difference in amplitude of ACC between the stimuli.Among the transducers, there was no significant difference in latency and amplitude of ACC, for both /sa/ and /si/ stimuli.Female participants showed earlier latency for 2N1 and larger amplitude of N1 and 2P2 than male participants, which was significant.

View Article: PubMed Central - PubMed

Affiliation: All India Institute of Speech and Hearing, India.

ABSTRACT
The objective of this study was to investigate the effect of stimuli, transducers and gender on the latency and amplitude of acoustic change complex (ACC). ACC is a multiple overlapping P1-N1-P2 complex reflecting acoustic changes across the entire stimulus. Fifteen males and 15 females, in the age range of 18 to 25 (mean=21.67) years, having normal hearing participated in the study. The ACC was recorded using the vertical montage. The naturally produced stimuli /sa/ and /si/ were presented through the insert earphone/loud speaker to record the ACC. The ACC obtained from different stimuli presented through different transducers from male/female participants were analyzed using mixed analysis of variance. Dependent t-test and independent t-test were performed when indicated. There was a significant difference in latency of 2N1 at the transition, with latency for /sa/ being earlier; but not at the onset portions of ACC. There was no significant difference in amplitude of ACC between the stimuli. Among the transducers, there was no significant difference in latency and amplitude of ACC, for both /sa/ and /si/ stimuli. Female participants showed earlier latency for 2N1 and larger amplitude of N1 and 2P2 than male participants, which was significant. ACC provides important insight in detecting the subtle spectral changes in each stimulus. Among the transducers, no difference in ACC was noted as the spectra of stimuli delivered were within the frequency response of the transducers. The earlier 2N1 latency and larger N1 and 2P2 amplitudes noticed in female participants could be due to smaller head circumference. The findings of this study will be useful in determining the capacity of the auditory pathway in detecting subtle spectral changes in the stimulus at the level of the auditory cortex.

No MeSH data available.