Gravelin & Whitfield (2019)

ANALYSIS GUIDELINES

Comparison/Nonintervention Research

KEY:

eta =   partial eta squared

f = female

m = male

MLU = mean length of utterance

NA = Not Applicable

P = participant or patient

PD = Parkinson disease

pmh = Patricia Hargrove, blog developer

SLP = speech-language pathologist

sps syllables per second

WNL = within normal limits

 

SOURCE: Gravlin, A. C., & Whitfield, J. A. (2019). Effect of Clear Speech on the duration of silent intervals at syntactic and phonemic boundaries in the speech of individuals with Parkinson disease. American Journal of Speech-Language Pathology, 28, 793-806.

 

REVIEWER(S): pmh

 

DATE:  August 10, 2020

 

ASSIGNED GRADE FOR OVERALL QUALITY: no grade assigned; this is not an intervention investigation

 

TAKE AWAY: Comparisons of silent durations in speakers with Parkinson disease (PD) and neurotypical controls in habitual and Clear Speech speaking conditions revealed some similarities. The findings suggest that PD speakers do change their speech production patterns when attempting to use Clear Speech. This may provide guidance to clinicians considering targeting Clear Speech when working with individuals with PD.

 

  1. What type of evidence was identified?

What was the type of design? Comparison Research; 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? B+

                                                                                                           

  1. Group membership determination:

– If there were groups, were participants randomly assigned to groups? No

– If there were groups and Ps were not randomly assigned to groups, were members of groups carefully matched? No

                                                                    

  1. Were experimental conditions concealed?

– from participants? No                                                                     

– from administrators of experimental conditions? No

– from analyzers/judges? No

 

  1. Were the groups adequately described? Yes

– How many participants were involved in the study?

  • total # of participants (Ps): 20
  • # of groups: 2
  • List names of groups and the number of Ps in each group:

     – speakers with PD (PD group) = 10

– control group (C group) = 10

  • Did all groups maintain membership throughout the investigation? Yes

CONTROLLED CHARACTERISTICS                                                     

  • gender: each group m = 5; f = 5
  • cognitive skills: “all” Ps within normal limits (WNL) on dementia screener (unclear whether is all PD and C Ps or just PD)
  • first language language: English
  • residence: USA Midwest
  • Hearing: all Ps WNL

DESCRIBED CHARACTERISTICS

  • age:

     PD = average 67 years (64-77 years)

     C = average 69 years (64-76 years)

  • educational level of clients:
  • medications: 9 of 10 Ps in PD group were taking carbidopa levodopa; 1 P in the PD group was taking Requipt; Ps in PD group were also taking other medications; all Ps from the PD groups were on medications at the time of testing
  • Diagnosis:

PD = idiopathic PD

     C = neurotypical

  • previous speech therapy: No P had received speech or voice therapy for 2 years
  • time since diagnosis: timing of PD diagnosis ranged from 2 to 11 years prior 

–  Were the groups similar? Unclear

  Were the communication problems adequately described? Yes

  • disorder type: hypokinetic dysarthria all 12 PD group 3 Ps also were hyperkinetic
  • functional level: severity of dysarthria ranged from mild to severe

 

  1. What were the different conditions for this research?
  • Subject (Classification) Groups? Yes

     – Parkinsons disease (P)

     – Control (C)

  • Experimental Conditions? Yes

     – Reading aloud using comfortable rate and loudness (habitual)

     – Reading aloud as clearly as possible (Clear Speech)

  • Criterion/Descriptive Conditions? No

 

  1. Were the groups controlled acceptably? Yes

 

  1. Were dependent measures appropriate and meaningful? Yes
  • OUTCOME #1: mean speaking rate in syllables per second (sps)
  • OUTCOME #2: inter-sentence silent duration
  • OUTCOME #3: intra-sentence silent duration
  • OUTCOME #4: between-word silent duration
  • OUTCOME #5: within-word silent duration
  • OUTCOME #6: combined between- and within-word silent durations preceded by fricatives
  • OUTCOME #7: combined between- and within-word silent durations preceded by sonorants
  • OUTCOME #8: combined between- and within-word silent durations preceded by stops

 

– The dependent measures were subjective were

  • OUTCOME #2: inter-sentence silent duration
  • OUTCOME #3: intra-sentence silent duration
  • OUTCOME #4: between-word silent duration
  • OUTCOME #5: within-word silent duration
  • OUTCOME #6: combined between- and within- word silent durations preceded by fricatives
  • OUTCOME #7: combined between- and within- word silent durations preceded by sonorants
  • OUTCOME #8: combined between- and within- word silent durations preceded by stops

–  The dependent/ outcome measure that was objective was

  • OUTCOME #1: mean speaking rate in sps

 

  1. Were reliability measures provided?
  • Interobserver for analyzers? Yes. For overall syntactic boundary judgments inter-observer reliability was 90%.
  • Intraobserver for analyzers? Yes. For overall syntactic boundary judgments intra-observer reliability was 93%.
  • Treatment or test administration fidelity for investigators? No

 

  1. Description of design:

– Ten Ps with PD and 10 neurotypical age-matched peers  \(C) participated in the investigation.

– The Ps read aloud a passage in 2 conditions:

∞ habitual speech and

∞ Clear Speech

– The investigators measured overall speech rate and silent durations. The silent durations were measured in several contexts:

∞ between sentence boundaries,

∞ within sentence boundaries,

∞ between words, and

∞ within words.

– The investigators also analyzed the silent duration with respect to the manner of articulation of the speech sound that followed the silence:

∞ stop,

∞ fricative, and

∞ sonorant.

– The investigators compared performance in the Habitual and Clear Speech conditions as well as the performance of the PD and C groups.

 

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

Only the comparisons that are significant  (e.g.,  p ≤ 0.05) are listed

RATE

  • OUTCOME #1: mean speaking rate in syllables per second (sps)

– No significant difference overall speaking rate for PD versus C groups.

– C Ps reduce speaking rate significantly between habitual and Clear Speech (Clear Speech was slower) but PD Ps rate for the 2 contexts was not significantly different.

LINGUISTIC BOUNDARIES

  • OUTCOME #2: inter-sentence silent duration

     – For Control Ps

∞ in the habitual condition duration of inter-sentence silences was significantly longer than

  • intra-sentence silences,
  • between word silences, and
  • within word silences.

– For PD Ps, although the pattern for habitual condition was similar to the Control Ps, none of the differences were significant.

– For C Ps, the comparison of habitual to Clear Speech silences revealed

∞ there was a significant increase in duration of silences at the inter-sentence boundary.

∞ the silent duration increases for all other boundaries (intra-sentence, word, intra-word) were significantly smaller than the increase for the inter-sentence boundary,

– The comparison of PD versus C speakers in the habitual and Clear Speech conditions indicated

∞ the PD speakers produced significantly smaller increases at the inter-sentence boundary than the Cs when comparing habitual and Clear Speech conditions.

– For PD Ps, the comparison of habitual to Clear Speech silences revealed

∞ there was a significant increase in duration of silences at the inter-sentence boundary.

∞ PD speakers’ increase in silence duration related to the habitual versus Clear Speech condition was significantly smaller for the inter-sentence boundaries.

 

  • OUTCOME #3: intra-sentence silent duration

– For C Ps, the comparison of habitual to Clear Speech silences revealed

∞ there was a significant increase in duration of silences at the intra-sentence boundary for Clear Speech.

– For PD Ps, the comparison of habitual to Clear Speech silences revealed

∞ there was a significant increase in duration of silences at the intra-sentence boundary.

 

  • OUTCOME #4: between-word silent duration

– For C Ps, the comparison of habitual to Clear Speech silences revealed

∞ there was a significant increase in duration of silences at the between-word boundary for Clear Speech.

– For PD Ps, the comparison of habitual to Clear Speech silences revealed

∞ there was a not significant increase in duration of silences at the between-word boundary.

– The comparison of PD versus C speakers in the habitual and Clear Speech conditions indicated

∞ PD speakers’ increase in silence duration related to the habitual versus Clear Speech condition was significantly smaller than the C speakers..

 

  • OUTCOME #5: within-word silent duration

– For C Ps, the comparison of habitual to Clear Speech silences revealed

∞ there was a significant increase in duration of silences at the within-word boundary for Clear Speech.

– For PD Ps, the comparison of habitual to Clear Speech silences revealed

∞ there was a significant increase in duration of silences at the within-word boundary.

      – The comparison of PD versus C speakers in the habitual and Clear Speech conditions indicated

∞ PD speakers’ increase in silence duration related to the habitual versus Clear Speech condition was significantly smaller than the C speakers.

 

PHONEMIC BOUNDARIES

  • OUTCOME #6: combined between and within words silent durations preceded by fricatives

∞ For both groups (PD and C), in the habitual condition when a stop consonant preceded a silence associated with between or within word pauses, it was significantly long than if the pause was preceded by a fricative or a sonorant.

∞ Overall, C Ps produced significantly longer silences in the Clear Speech condition compared to the habitual condition. For the comparison of Clear Speech productions,

  • silences preceded by stops were significantly longer than silences preceded by fricatives or sonorants.

 

  • OUTCOME #7: combined between and within words silent durations preceded by sonorants

∞ For both groups (PD and C), in the habitual condition when a stop consonant preceded a silence associated with between or within word pauses, it was significantly long than if the pause was preceded by a fricative or a sonorant.

∞ Overall, C Ps produced significantly longer silences in the Clear Speech condition compared to the habitual condition. For the comparison of Clear Speech productions,

  • silences preceded by stops were significantly longer than silences preceded by fricatives or sonorants.

∞ PD Ps produced significantly larger increases in silences from habitual to Clear Speech conditions for pauses that were preceded by sonorants compared to stops or fricatives.

 

  • OUTCOME #8: combined between and within words silent durations preceded by stops

∞ For both groups (PD and C), in the habitual condition when a stop consonant preceded a silence associated with between or within word pauses, it was significantly long than if the pause was preceded by a fricative or a sonorant.

∞ Overall, C Ps produced significantly longer silences in the Clear Speech condition compared to the habitual condition but

  • silences preceded by stops were significantly longer than silences preceded by fricatives or sonorants.

∞ Comparing C and PD groups, PD Ps produced significantly shorter silences for pauses preceded by stops in the Clear Speech condition.

– What were the statistical tests used to determine significance? t-test, ANOVA, Linear-mixed model analysis

– Were effect sizes provided? No 

– Were confidence interval (CI) provided? No

 

  1. Summary of correlational results: NA

 

  1. Summary of descriptive results: Qualitative research. —NA

 

  1. Brief summary of clinically relevant results:
  • The purpose of this investigation was to explore the duration of silences at selected linguistic and phonemic boundaries of participants (Ps) with PD and their neurotypical controls (C) when speaking in habitual and Clear Speech conditions.
  • Both groups of speakers increased the duration of silences at linguistic boundaries in the Clear Speech condition compared to the habitual condition.
  • There were differences between the PD and C groups with respect to the changes at the linguistic boundaries with the PD group tending to produce fewer and shorter increases than the C group.
  • While the C group routinely showed changes at the phonemic boundaries, PD speakers’ changes were less robust.
  • Clinicians may consider using Clear Speech to facilitate the use of pauses (particularly inter-sentence pauses) in the speech of speakers with P.
  • When measuring progress or change in speakers with PD, clinicians should temper the use of metrics such as speaking rate because

– there was not a significant difference between PD and C speakers overall speaking rate and

– PD speakers did not regularly modulate rate in the habitual as opposed to Clear Speech conditions.

 

ASSIGNED GRADE FOR QUALITY OF EXTERNAL EVIDENCE: B+

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: