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The mechanism of speech processing in congenital amusia: evidence from Mandarin speakers.

Liu F, Jiang C, Thompson WF, Xu Y, Yang Y, Stewart L - PLoS ONE (2012)

Bottom Line: However, they performed as well as controls on word identification, and on statement-question identification and discrimination in natural speech.Only when the tasks relied mainly on pitch sensitivity did amusics show impaired performance compared to controls.Further studies on a larger sample of Mandarin amusics and on amusics of other language backgrounds are needed to consolidate these results.

View Article: PubMed Central - PubMed

Affiliation: Center for the Study of Language and Information, Stanford University, Stanford, California, United States of America. liufang@uchicago.edu

ABSTRACT
Congenital amusia is a neuro-developmental disorder of pitch perception that causes severe problems with music processing but only subtle difficulties in speech processing. This study investigated speech processing in a group of Mandarin speakers with congenital amusia. Thirteen Mandarin amusics and thirteen matched controls participated in a set of tone and intonation perception tasks and two pitch threshold tasks. Compared with controls, amusics showed impaired performance on word discrimination in natural speech and their gliding tone analogs. They also performed worse than controls on discriminating gliding tone sequences derived from statements and questions, and showed elevated thresholds for pitch change detection and pitch direction discrimination. However, they performed as well as controls on word identification, and on statement-question identification and discrimination in natural speech. Overall, tasks that involved multiple acoustic cues to communicative meaning were not impacted by amusia. Only when the tasks relied mainly on pitch sensitivity did amusics show impaired performance compared to controls. These findings help explain why amusia only affects speech processing in subtle ways. Further studies on a larger sample of Mandarin amusics and on amusics of other language backgrounds are needed to consolidate these results.

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Related in: MedlinePlus

Boxplots of amusics and controls' scores on the four word discrimination tasks (in ‘percentage of hits – percentage of false alarms’; %H – %FA).(A) pre-focus word discrimination, (B) pre-focus glide discrimination, (C) post-focus word discrimination, and (D) post-focus glide discrimination. Individual scores are represented by black dots, with those at the same horizontal level having identical values, and those lying beyond the whiskers being outliers (which are further indicated by open circles in the middle).
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pone-0030374-g003: Boxplots of amusics and controls' scores on the four word discrimination tasks (in ‘percentage of hits – percentage of false alarms’; %H – %FA).(A) pre-focus word discrimination, (B) pre-focus glide discrimination, (C) post-focus word discrimination, and (D) post-focus glide discrimination. Individual scores are represented by black dots, with those at the same horizontal level having identical values, and those lying beyond the whiskers being outliers (which are further indicated by open circles in the middle).

Mentions: Figure 3 shows the results of the word/glide discrimination tasks (see Tables S4 and S5 for individual scores and reaction times). Mixed-effects ANOVA with Subject (individual participants) as the random effect, Group (amusic versus control) the between-subject factor, and Stimulus (word versus glide) and Focus (pre versus post) the within-subject factors revealed significant main effects of Group [F(1,24) = 13.71, p = 0.001], Stimulus [F(1,72) = 81.56, p<0.0001], and Focus [F(1,72) = 16.37, p = 0.0001]. No significant interactions were found. This indicates that, regardless of focus condition, amusics performed significantly worse than controls on both word discrimination and glide discrimination. Both groups performed significantly better on glide discrimination than word discrimination [amusics: F(1,36) = 32.60, p<0.0001; controls: F(1,36) = 56.53, p<0.0001]. While controls achieved significantly better performance under the pre-focus condition than the post-focus condition [F(1,36) = 20.83, p<0.0001], the effect of focus on amusics' performance was only marginally significant [F(1,36) = 2.87, p = 0.099].


The mechanism of speech processing in congenital amusia: evidence from Mandarin speakers.

Liu F, Jiang C, Thompson WF, Xu Y, Yang Y, Stewart L - PLoS ONE (2012)

Boxplots of amusics and controls' scores on the four word discrimination tasks (in ‘percentage of hits – percentage of false alarms’; %H – %FA).(A) pre-focus word discrimination, (B) pre-focus glide discrimination, (C) post-focus word discrimination, and (D) post-focus glide discrimination. Individual scores are represented by black dots, with those at the same horizontal level having identical values, and those lying beyond the whiskers being outliers (which are further indicated by open circles in the middle).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3275596&req=5

pone-0030374-g003: Boxplots of amusics and controls' scores on the four word discrimination tasks (in ‘percentage of hits – percentage of false alarms’; %H – %FA).(A) pre-focus word discrimination, (B) pre-focus glide discrimination, (C) post-focus word discrimination, and (D) post-focus glide discrimination. Individual scores are represented by black dots, with those at the same horizontal level having identical values, and those lying beyond the whiskers being outliers (which are further indicated by open circles in the middle).
Mentions: Figure 3 shows the results of the word/glide discrimination tasks (see Tables S4 and S5 for individual scores and reaction times). Mixed-effects ANOVA with Subject (individual participants) as the random effect, Group (amusic versus control) the between-subject factor, and Stimulus (word versus glide) and Focus (pre versus post) the within-subject factors revealed significant main effects of Group [F(1,24) = 13.71, p = 0.001], Stimulus [F(1,72) = 81.56, p<0.0001], and Focus [F(1,72) = 16.37, p = 0.0001]. No significant interactions were found. This indicates that, regardless of focus condition, amusics performed significantly worse than controls on both word discrimination and glide discrimination. Both groups performed significantly better on glide discrimination than word discrimination [amusics: F(1,36) = 32.60, p<0.0001; controls: F(1,36) = 56.53, p<0.0001]. While controls achieved significantly better performance under the pre-focus condition than the post-focus condition [F(1,36) = 20.83, p<0.0001], the effect of focus on amusics' performance was only marginally significant [F(1,36) = 2.87, p = 0.099].

Bottom Line: However, they performed as well as controls on word identification, and on statement-question identification and discrimination in natural speech.Only when the tasks relied mainly on pitch sensitivity did amusics show impaired performance compared to controls.Further studies on a larger sample of Mandarin amusics and on amusics of other language backgrounds are needed to consolidate these results.

View Article: PubMed Central - PubMed

Affiliation: Center for the Study of Language and Information, Stanford University, Stanford, California, United States of America. liufang@uchicago.edu

ABSTRACT
Congenital amusia is a neuro-developmental disorder of pitch perception that causes severe problems with music processing but only subtle difficulties in speech processing. This study investigated speech processing in a group of Mandarin speakers with congenital amusia. Thirteen Mandarin amusics and thirteen matched controls participated in a set of tone and intonation perception tasks and two pitch threshold tasks. Compared with controls, amusics showed impaired performance on word discrimination in natural speech and their gliding tone analogs. They also performed worse than controls on discriminating gliding tone sequences derived from statements and questions, and showed elevated thresholds for pitch change detection and pitch direction discrimination. However, they performed as well as controls on word identification, and on statement-question identification and discrimination in natural speech. Overall, tasks that involved multiple acoustic cues to communicative meaning were not impacted by amusia. Only when the tasks relied mainly on pitch sensitivity did amusics show impaired performance compared to controls. These findings help explain why amusia only affects speech processing in subtle ways. Further studies on a larger sample of Mandarin amusics and on amusics of other language backgrounds are needed to consolidate these results.

Show MeSH
Related in: MedlinePlus