Nadig & Shaw (2011)

ANALYSIS

Comparison Research

 

 

KEY:   

 

ADOS = Autism Diagnostic Observation Schedule

ASD = autism spectrum disorder

CELF-4 = Clinical Evaluation of Language Fundamental, 4th edition

HFA = High Functioning Autism

P = participant

pmh = Patricia Hargrove, blog developer

SCQ = Social Communication Questionnaire

TYP = typical peer

 

 

SOURCE: Nadig, A., & Shaw, H. (2011). Acoustic and perceptual measurement of expressive prosody in High-Functioning Autism: Increased pitch range and what it means to listeners. Journal of Autism and Developmental Disorders, 42, 499-511.

REVIEWER(S): pmh

DATE: March 31, 2015

ASSIGNED GRADE FOR OVERALL QUALITY: B (The highest possible grade, based on the design of the investigation was B+.)

TAKE AWAY: Findings support the contention that Ps with High Functioning Autism (HFA) produced larger than typical pitch ranges in speech of Ps with although group data revealed that listeners did not perceive the pitch variability of speakers with HFA and their typically developing peers to be significantly different. Other measures (mean pitch and rate) were not significantly different in HFA children/adolescents and their typically developing peers (TYP.) Although there were moderate correlations between perceptual and acoustic measures of mean pitch and speaking rate, the correlation between the acoustic and perceptual measure of pitch change/variability was not significant.

 

  1. What type of evidence was identified?
  • What was the type of evidence? Prospective, Nonrandomized Group Design with Controls
  • What was the focus of the research? Clinically Related
  • What was the level of support associated with the type of evidence? Level = B+

                                                                                                           

 

  1. Group membership determination:
  • If there were groups, were participants randomly assigned to groups? No
  • If there were groups and participants were not randomly assigned to groups, were members of groups carefully matched? Yes

                                                                    

  1. Were experimental conditions concealed?
  • from participants? No
  • from administrators of experimental conditions? No
  • from analyzers/judges? Yes

                                                                    

 

  1. Were the groups adequately described? Yes
  • How many participants were involved in the study? There were 3 experiments. The numbers for each experiment are listed. In addition, judges were used to rate the speech samples from Experiment 2. These judges will be described below as “raters.”

 

EXPERIMENT 1 AND 2 (the data from the same participants, Ps, were analyzed in Experiments 1 and 2)

  • total # of participant: 28
  • # of groups: 2
  • # of participants in each group: 15, 13
  • List names of groups: High Functioning Autism (HFA) = 15; Typically Developing (TYP) = 13
  • Did all groups maintain membership? Yes

 

EXPERIMENT 3 (Five of the participants, from the High-Functioning Autism group and 10 of the typically developing, TYP, group also participated in Experiments 1 and 2.)

  • total # of participant: 26
  • # of groups:  2
  • # of participants in each group: 15, 11
  • List names of groups: HFA = 15; TYP = 11
  • Did all groups maintain membership? Yes

 

RATERS

  • total # of participant: 32
  • # of groups: 1
  • # of participants in the group: 32
  • List names of group: raters
  • Did all groups maintain membership? Yes
  • The following variables were described:

EXPERIMENT 1 AND 2

  • age: mean age HFA = 11-0 years; TYP = 11-0 years
  • gender: HFA 13m, 2f; TYP 11m, 2f
  • cognitive skills: mean IQ HFA = 105; TYP = 111
  • language: Clinical Evaluation of Language Fundamental, 4th edition (CELF-4) mean HFA = 109; TYP = 115
  • Measures of Autistic Symptoms

– HFA

  • Social Communication Questionnaire (SCQ, parental report) — mean = 26
  • Autism Diagnostic Observation Schedule (ADOS) algorithm score–13
  • ADOS total score (sum of all items) –26

– TYP

  • SCQ (parental report)—2
  • ADOS algorithm score—not applicable (NA)
  • ADOS total score (sum of all items)–NA

EXPERIMENT 3

  • age: mean age HFA = 10-6 years; TYP = 10-08 years
  • gender: HFA 12m, 3f; TYP 9m, 2f
  • cognitive skills: mean IQ HFA = 111; TYP = 116
  • language: CELF-4 mean HFA = 108; TYP = 117

– HFA

  • Social Communication Questionnaire (SCQ, parental report) — mean = 26
  • Autism Diagnostic Observation Score (ADOS) algorithm score–15
  • ADOS total score (sum of all items) –25

– TYP

  • SCQ (parental report)—2
  • ADOS algorithm score—not applicable (NA)
  • ADOS total score (sum of all items)–NA

 

RATERS (from Experiment 2)

  • educational level of rater: Applied Masters students in Communication Sciences and Disorders
  • Were the groups similar before intervention began? Yes. With the exception of the SCQ, the TYP and HFA groups were similar                                                      
  • Were the communication problems adequately described? No
  • disorder type: HFA
  • functional level: performance of HFA group was within normal limits (WNL) on the CELF-4 but the Ps with HFA evidenced social communication problems as noted by their score on the SCQ. All Ps in the HFA group preformed above the 15 on the SCQ which is consistent with the diagnosis of autism spectrum disorder (ASD.) None of the TYP group scored 15 or higher on the SCQ.

 

 

  1. What were the different conditions for this research?
  • Subject (Classification) Groups? Yes–diagnostic classification (HFA; TYP)
  • Experimental Conditions? No
  • Criterion/Descriptive Conditions? Yes

– Experiments 1 and 2: face-to-face conversational speech

– Experiment 3: referential communication task

 

  1. Were the groups controlled acceptably? Yes

 

 

  1. Were dependent measures appropriate and meaningful? Yes

The dependent measures were

EXPERIMENT #1: conversational speech

  • Measure 1: Pitch range
  • Measure 2: Mean Pitch
  • Measure 3: Speech Rate
  • Measure 4: Relationship between acoustic measures and P characteristics such as IQ, language level, severity of autism, etc.

EXPERIENT #2: conversational speech

  • Measure 5: Pitch range—used the same data as Experiment 1
  • Measure 6: Mean pitch– used the same data as Experiment 1
  • Measure 7: Speech rate– used the same data as Experiment 1
  • Measure 8: Overall perceptual impression of normalcy
  • Measure 9: Perceptual rating of pitch change
  • Measure 10: Perceptual rating of mean pitch
  • Measure 11: Perceptual rating of speaking rate
  • Measure 12: Relationship between acoustic and perfection of measures
  • Measure 13: Relationship between acoustic measures and P characteristics such as IQ, language level, severity of autism, etc.

EXPERIMENT #3: referential communication task

  • Measure 14: Pitch range
  • Measure 15: Mean pitch
  • Measure 16: Speech rate
  • Measure 17: Relationship between acoustic measures and P characteristics such as IQ, language level, severity of autism, etc.

The dependent measures that are subjective are

EXPERIMENT #1: conversational speech

  • Measure 4: Relationship between acoustic measures and P characteristics such as IQ, language level, severity of autism, etc.

EXPERIENT #2: conversational speech

  • Measure 9: Perceptual rating of pitch change—same data as Experiment #1
  • Measure 10: Perceptual rating of mean pitch—same data as Experiment #1
  • Measure 11: Perceptual rating of speaking rate—same data as Experiment #1
  • Measure 12: Relationship between acoustic and perfection of measures
  • Measure 13: Relationship between acoustic measures and P characteristics such as IQ, language level, severity of autism, etc.

EXPERIMENT #3: referential communication task

  • Measure 17: Relationship between acoustic measures and P characteristics such as IQ, language level, severity of autism, etc.

 

– The dependent measures that are objective are

EXPERIMENT #1: conversational speech

  • Measure 1: Pitch range
  • Measure 2: Mean Pitch
  • Measure 3: Speech Rate

EXPERIENT #2: conversational speech

  • Measure 5: Pitch range—same data as Experiment #1
  • Measure 6: Mean pitch—same data as Experiment #1
  • Measure 7: Speech rate—same data as Experiment #1

EXPERIMENT #3: referential communication task

  • Measure 14: Pitch range
  • Measure 15: Mean pitch
  • Measure 16: Speech rate

                                         

 

  1. Were reliability measures provided?

– Interobserver for analyzers? No

Intraobserver for analyzers? No

Treatment fidelity for investigators? No

 

 

  1. Description of design:
  • This investigation involved 3 experiments:

— Experiment 1: The acoustical analysis of selected aspects of prosody from brief samples of conversation

— Experiment 2: The perceptual rating of selected aspects of prosody from brief samples of conversation

— Experiment 3: The acoustical analysis of selected aspects of prosody from a referential communication task

  • Participants for each of the investigations were school-age children (8 to 14 years old) who had been diagnosed as HFA and their typically developing peers.
  • The investigators elicited the samples from the Ps and then analyzed them acoustically or perceptually to extract the measures under consideration.

 

 

  1. What were the results of the statistical (inferential) testing?

 

– The comparisons that are significant (p ≤ 0.05) are

EXPERIMENT #1: conversational speech

  • Measure 1: Pitch range—HFA significantly wider than TYP

EXPERIENT #2: conversational speech

  • Measure 5: Pitch range — HFA significantly wider than TYP (used same data as Experiment 1)
  • Measure 8: Overall perceptual impression of normalcy—TYP was significantly higher than HFA

EXPERIMENT #3: referential communication task

  • Measure 14: Pitch range— HFA significantly wider than TYP

– The statistical tests that were used to determine significance were

  • t-test:
  • Mann-Whitney U

– Were effect sizes provided? Yes

EXPERIMENT #1: conversational speech

  • Measure 1: Pitch range – r = 0.67 (moderate effect)
  • Measure 2: Mean Pitch – r = 0.30 (small effect)
  • Measure 3: Speech Rate – r = 0.25 (small effect)

EXPERIENT #2: conversational speech

  • Measure 5: Pitch range – r = 0.67 (moderate effect) same data as Experiment 1
  • Measure 6: Mean pitch – r = 0.30 (small effect) same data as Experiment 1
  • Measure 7: Speech rate – r = 0.25 (small effect) same data as Experiment 1
  • Measure 8: Overall perceptual impression of normalcy – r = 0.48 (small effect)
  • Measure 9: Perceptual rating of pitch change – r = 0.17 (no effect)
  • Measure 10: Perceptual rating of mean pitch – r 0.09 (no effect)
  • Measure 11: Perceptual rating of speaking rate — r 0.22 (small effect)

EXPERIMENT #3: referential communication task

  • Measure 14: Pitch range –r = 0.40 (small effect)
  • Measure 15: Mean pitch –r = 0.22 (small effect)
  • Measure 16: Speech rate — r = 0.03 (no effect)

Were confidence interval (CI) provided? No

Were correlational statistics provided: Yes

– The results of correlational analyses are

EXPERIMENT #1: conversational speech

  • Measure 4: Relationship between acoustic measures and P characteristics such as IQ, language level, severity of autism, etc.

— pitch range: none of the correlations were significant for either group (HFA, TYP)

— mean pitch and rate: not reported

EXPERIENT #2: conversational speech

  • Measure 12: Relationship between acoustic and perfection of measures

HFA:

  • pitch change—acoustic and perceptual measures –not significantly correlated (NOTE: both HFA and TYP were not significantly correlated despite the finding that acoustic measures of pitch change were significantly higher for HFA. Visual inspection of the scatterplots suggested that the relationship between acoustic and perceptual measures was more linear in TYP and HFA was flat suggesting different patterns.)
  • mean pitch– acoustic and perceptual measures: significant correlation (r = 0.53, moderate correlation)
  • mean rate — acoustic and perceptual measures: significant correlation (r = 0.65, strong correlation)

 

     – TYP:

  • pitch change—acoustic and perceptual measures –not significantly correlated (NOTE: both HFA and TYP were not significantly correlated despite the finding that acoustic measures of pitch change were significantly higher for HFA. Visual inspection of the scatterplots suggested that the relationship between acoustic and perceptual measures was more linear in TYP and HFA was flat suggesting different patterns.)
  • mean pitch– acoustic and perceptual measures—correlation not significant
  • mean rate — acoustic and perceptual measures: significant correlation (r = 0.87, strong correlation
  • Measure 13: Relationship between acoustic measures and P characteristics such as IQ, language level, severity of autism, etc.

no significant correlations for either group

EXPERIMENT #3: referential communication task

  • Measure 17: Relationship between acoustic measures and P characteristics such as IQ, language level, severity of autism, etc.

     – HFA

  • pitch range not significantly correlated with any of the P characteristics
  • correlations with the other acoustic measures were not reported

     – TYP

  • pitch range not significantly correlated with any of the P characteristics

 

  1. Brief summary of clinically relevant results:
  • Using conversational speech and speech during a referential communication task, the investigators determined that Ps with HFA produced speech with larger pitch ranges than typically developing peers. Thus, clinicians (Cs) = should expect a broader pitch range in speech of Ps with HFA rather than a smaller one (which one might expect from the extant clinical literature) using acoustic measures.
  • Using conversational, the investigators determined that raters did not perceive differences between in pitch variability of Ps with HFA and their typically developing peers to be significantly different. Therefore, Cs should not expect that they will perceive the pitch variability to be larger than typically developing peers. If Cs do perceive the P to be monotonal, acoustic measurements may be in order to clarify pitch variability. Despite the fact that there were no significant differences in overall performance, analysis of individual performances suggested that raters judged Ps with HFA to have more extreme (broad and narrow) pitch ranges.
  • The raters judged the speech of Ps with HFA to be significantly more atypical than the TYP group. There is, therefore, evidence for perceived differences between Ps with HFA and their typically developing peers. The cause of this difference is beyond the scope of this paper.

 

ASSIGNED GRADE FOR QUALITY OF EXTERNAL EVIDENCE: B

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