Yorkston et al. (2007)

SECONDARY REVIEW (SNR) CRITIQUE

Source:  Yorkston, K. M., Hakel, M., Beulelman, D. R., & Fager, S. (2007). Evidence for effectiveness of treatment of loudness, rate, or prosody in dysarthria: A systematic review. Journal of Medical Speech-Language Pathology, 15 (2), xi – xxxvi.

 

Reviewer(s):  pmh

 

Date:   September 5, 2013

 

Overall Assigned Grade:  A-

 

Level of Evidence:  A+

 

Take Away:  This well-executed Systematic Review is limited by the small number of sources. Loudness targets had the strongest evidence supporting the LSVT approach. Rate and prosody interventions as well as clarity/intelligibility also were reviewed.  

 

What type of secondary review?  Narrative Systematic Review

 

1.  Were the results valid? Yes

a.  Was the review based on a clinically sound clinical question?  Yes

b.  Did the reviewers clearly describe reasonable criteria for inclusion and exclusion of literature in the review (i.e., sources)?  Yes

c.  The authors noted that they reviewed the following resources:

•  hand searches

•  internet based databases 

•  references from identified literature x

d.  Did the sources involve only English language publications?  Yes

e.  Did the sources include unpublished studies?  No

f.  Was the time frame for the publication of the sources sufficient?  Yes

g.  Did the reviewers identify the level of evidence of the sources?  Yes. The reviewers noted the type (phase) of research of each of the sources.

h.  Did the reviewers describe procedures used to evaluate the validity of each of the sources?  Yes

i.  Was there evidence that a specific, predetermined strategy was used to evaluate the sources?  Yes

j.  Did the reviewers or review teams rate the sources independently?  Yes

k.  Were interrater reliability data provided?  No

l.  If the reviewers provided interrater reliability data, list them:   NA

m.  If there were no interrater reliability data, was an alternate means to insure reliability described?  No

n.  Were assessments of sources sufficiently reliable?  Not applicable

o.  Was the information provided sufficient for the reader to undertake a replication?  Yes

p.  Did the sources that were evaluated involve a sufficient number of participants?  Yes

q.  Were there a sufficient number of sources?  Yes

2.  Description of outcome measures:

•  Outcome #1:  Improved (usually increased) loudness

•  Outcome #2:  Improved (usually decreased) rate of speech

•  Outcome #3:  Improved acoustic (e.g., fo contours, relative intensity, duration) and/or perceptual (e.g., stress patterns, pauses, naturalness)

•  Outcome #4:  Improved clarity or overall intelligibility of speech

 

3.  Description of results:

a.  What evidence-based practice (EBP) measures were used to represent the magnitude of the treatment/effect size?  None

b.  Summarize overall findings of the secondary review:

Outcome #1:  Improved (usually increased) loudness

•  Strong support for the use of LSVT to increase loudness

 

Outcome #2:  Improved (usually decreased) rate of speech

•  Good evidence supporting the ability of a variety of treatment techniques to improve rate of speech.  In addition, several sources provided evidence between improvement in speaking rate and intelligibility.

 

Outcome #3:  Improved acoustic (e.g., fo contours, relative intensity, duration) and/or perceptual (e.g., stress patterns, pauses, naturalness)]

•  It is hard to state conclusions about the effectiveness of interventions for prosody for speakers with dysarthria because of the diversity of prosodic problems associated with dysarthria. Nevertheless, overall the reviewed sources yielded improved acoustic and/or perceptual rating of prosody, although Ps were not within normal limits.

 

Outcome #4:  Improved clarity or overall intelligibility of speech

     •  The investigators did not present a finding for this outcome due, in part, to the small number of investigations.

 

c.  Were the results precise?  Unclear/Variable

d.  If confidence intervals were provided in the sources, did the reviewers consider whether evaluations would have varied if the “true” value of metrics were at the upper or lower boundary of the confidence interval?  Not Applicable

e.  Were the results of individual studies clearly displayed/presented?  Yes

f.  For the most part, were the results similar from source to source?  Yes

g.  Were the results in the same direction?  Yes

h.  Did a forest plot indicate homogeneity?  Not Applicable

i.  Was heterogeneity of results explored?  Yes. Reviewers tried to identify P characteristics associated with positive outcome.

j.  Were the findings reasonable in view of the current literature?  Yes

k.  Were negative outcomes noted?  Yes  

                                                                                                                   

4.  Were maintenance data reported?  Yes. Reviewers summarized follow-up data when it was reported in the source. Generally, maintenance was limited.

 

 

SUMMARY OF INTERVENTION

 

Prosodic Targets: 

•  Loudness

•  Rate

•  Prosody (fo contours, relative intensity, duration, stress patterns, pauses, naturalness)

Nonprosodic Targets:

•  Clarity/Intelligibility

 

For each procedure detailed in the review, provide the following information:

Description of Procedure for Outcome #1:  Loudness

•  LSVT is the most frequently represented technique.

•  Procedures were not clearly described  but they include intensive, high effort intervention focusing on healthy increased phonatory effort, vocal fold adduction, and respiration.

Evidence Supporting Procedure for Outcome #1—Loudness

•  Improvements in loudness and other aspects of communication were reported consistently. There were some reports of limited maintenance.

Evidence Contraindicating Procedure for Outcome #1—Loudness

•  There were some reports of limited maintenance.

•  Procedures were not clearly described.

Description of Procedures for Outcome #2– Rate

•  There were 3 classes of rate intervention techniques: pacing, computer-based, and biofeedback.

•  Many of the investigation treated rate to improve intelligibility.

Evidence Supporting Procedure for Outcome #2—Rate

•  Rate (and intelligibility) improved with administration of each of the rate techniques.

Evidence Contraindicating Procedure for Outcome #2—Rate

•  Unclear how C selects target rate.

•  Need information about maintenance.

Description of Procedures for Outcome #3—Prosody  (fo contours, relative intensity, duration, stress patterns, pauses, naturalness)

•  There major 2 classes of prosodic intervention techniques: behavioral instruction and biofeedback.

•  However, the targets varied due to individual differences.

Evidence Supporting Procedure for Outcome #3—Prosody

•  Reviewed sources reported improvement in targets.

Evidence Contraindicating Procedure for Outcome #3—Prosody

•  Heterogeneous nature of prosodic impairment and the small number of sources it is difficult to make general statements.

Description of Procedures for Outcome #4—Intelligibility/Clarity 

•  Most of the interventions provided feedback and/or instructions about improving the clearness of speech. Only one of the six interventions used prosody; in this case the technique involved contrastive stress.

Evidence Supporting Procedures for Outcome #4—Intelligibility/Clarity

•  The interventions involving feedback were more successful than those with instruction. However, this conclusion should be considered in light of the small number of studies.

Evidence Contraindicating Procedures for Outcome #4 Intelligibility/Clarity

•  Small number of studies prevent making of recommendations.

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3 Responses to Yorkston et al. (2007)

  1. SEO says:

    Howdy! Would you mind if I share your blog with my zynga group?
    There’s a lot of folks that I think would really appreciate your
    content. Please let me know. Cheers

    • Please feel free to share this blog with your group! In the future we will be adding a page that indexes the reviews by area of impairment and we will be starting to review research pertaining to the nature of prosodic disorders.

    • Please feel free to share the blog with your group. We will be adding an index based on impairment time and reviews concerned with prosodic disorders shortly.

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