Brooks & Ploog (2013)

SOURCE: Brooks, P. J., & Ploog, B. O. (2013). Attention to emotional tone of voice in speech perception in children with autism. Research in Autism Spectrum Disorders, 7, 845-857.




DATE: May 21, 2014


ASSIGNED GRADE FOR OVERALL QUALITY: B(The highest possible grade for this design is B+.)


POPULATION: Autism Spectrum Disorder; Child, Adolescent



  • To replicate and expand previous research (Ploog et al., 2009) using video-game methodology and to explore the perception of changes in prosody.



• NOTE: The experimental tasks were concerned with the perception of prosodic change but were not concerned with the linkage of meaning and prosodic change.

• Overall, Ps with Autism Spectrum Disorder (ASD) did not show evidence of a problem perceiving differences between representative of 2 emotions: grouchy and enthusiastic.

• However, Ps with ASD required approximately two times the number of trials to advance out of the training phase of the experiment than typically developing children (TYP).

• Nevertheless, the Ps with ASD were able to reach criterion.

• In the testing phase, the experimenters also included some training tasks. Ps with ASD underperformed TYP peers but they did evidence the ability to discriminate.

• During the testing phase, TYP peers preferred the enthusiastic prosody to the grouchy prosody. Ps with ASD did not have a preference. (To me this could suggest a problem/difference with linking perception of prosody to meaning.)

• The video game used in this game has potential for testing Ps with ASD who are functioning at a variety of skill levels.



1. What type of evidence was identified? Prospective, Nonrandomized Group Comparison Design



2. Group membership determination:

a. If there were groups of participants were members of groups matched? Yes

b. Describe the matching strategy:

• Ps with ASD and TYP peers were matched by age only.


3. Was participants’ communication status concealed?

a. from participants? No

b. from assessment administrators? No

c. from data analyzers? No



4. Were the groups adequately described? No

a. How many participants were involved in the study?

• total # of participant: 28 originally

• was group membership maintained throughout the experiment? No, the group of Ps with ASD originally numbered 15 but 2 Ps withdrew.

• # of groups: 2

• List names of groups:

Ps with ASD (ASD)

– Typically developing (TYP) peers

• # of participants in each group:

– ASD = 13

– TYP = 13



The following variables were controlled:

• hearing: hearing loss was an exclusionary criterion.

• diagnosis: ASD or TYP

– The following variables were described:

• age:   mean 9 years (ASD, TYP); range 5 years, 0 months to 17 years, 6 months (ASD), range 5 years, 4 months to 16 years (TYP)

• gender: 10 m, 3 f (ASD); 6 m, 7 f (TYP):

• language: reported Ps with ASD had a variety of language skills including being no verbal. No documentation was provided.


c. Were the communication problems adequately described? No, the investigators reported Ps with ASD had a variety of language skills including being non verbal but they provided no documentation.



5. What were the different conditions for this research?

a. Subject (Classification) Groups?



b. Experimental Conditions?      

• Prosody: enthusiastic for statement; grouchy for statement

• Content: simple sentence pair with similar grammatical structures but different lexical items

• Test: statement (S+); question (S-)—used for training only



6. Were the groups controlled acceptably? No



7. Were dependent measures appropriate and meaningful? Yes

a. Dependent measure:

  • Dependent Measure #1: percentage of choices indicating preference for one of two sentences during a video game task.

b. The dependent measures is not subjective.

c. The dependent measure is objective.



8. Were reliability measures provided?                                   

a. Interobserver for analyzers? No

b. Intraobserver for analyzers? No

c. Treatment fidelity for investigators? Not Applicable


9. Description of design:

• mixed design—between subjects (Group—ASD, TYP) and within subjects (Prosody—grouchy, enthusiastic)


10. What were the results of the inferential statistical testing


a. Comparisons that are significant ( p ≤ 0.05):

Dependent Measure #1: percentage of choices indicating preference for one of two sentences during a video game task.

• only noting prosodic comparisons!

• number of training sessions needed to reach criterion: Ps with ASD needed 2 times the number sessions

• Although both subject groups performance was above chance, TYP peers performance was significantly better on training tasks within testing sessions.

• The significant interaction between Prosody and Groups on preference trials indicates that ASD and TYP attend differently to prosody.


b. What were the statistical tests used to determine significance?


• t-tests


c. Were effect sizes provided? No

d. Were confidence interval (CI) provided? No



11. What were the results of the correlational statistical testing? No correlations/



12. What were the results of the descriptive analysis? There were no descriptive analyses beyond those which accompanied inferential statistical analysis.




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