Pennington et al. (2006)


Single Subject Designs


SOURCE:  Pennington, L., Smallman, C., & Farrier, F. (2006). Intensive dysarthria therapy for older children with cerebral palsy:  Findings from six cases.  Child Language Teaching and Therapy, 22, 255-273.




DATE:  7.13.13

ASSIGNED OVERALL GRADE:  D- (Due to level of evidence, the highest possible grade was D+.)


TAKE AWAY:  These 6 case studies indicate that a systems approach to improving the speech of 10-18 year olds with cerebral palsy may have potential to improve intelligibility of single words but not connected speech. The investigators described the procedures in only general terms.


1.  What was the focus of the researchClinical Research


2.  What type of evidence was identified?                              

a.  What  type of single subject design was used?  Case StudiesDescription with Pre and Post Test Results

b.  What was the level of support associated with the type of evidence?  Level =   D+    


3.  Was phase of treatment concealed?                                             

a.  from participants?  No                             

b.  from clinicians?  No                                 

c.  from data analyzers?  Yes


4.  Were the participants adequately described?  Yes

a.  How many participants were involved in the study?  6      

4b.  Were the following characteristics/variables actively controlled or described?


•  age: 10 years or older (10-18 years, mean = 15 years)

•  diagnosis:  mild to severe dysarthria associated with cerebral palsy

•  education of participant:  in a single special school in the UK


•  gender:  4f, 2m

•  cognitive skills:  4 WNL, 2 moderate learning difficulty

•  description of cerebral palsy:  5 quadriplegia, 1 hemiplegia

•  expressive language:  all spoke in sentence; usually simple sentence structures

•  receptive language:  at least 8.5 years on the Test of Receptive Grammar


c.  Were the communication problems adequately described?  Yes

•  The disorder type: dysarthria

•  Other aspects of communication that were described:

–  intelligibility:  impaired

–  type of dysarthria:    3 spastic, 3 mixed

–  severity of dysarthria:  1 mild, 3 moderate, 2 severe

–  presence of apraxia:  1 yes, 5 no

–  prosodic characteristics:  3 slow speech, 6 low pitch, 2 reduced volume, 3  monotone, 1 variable volume, 2 narrow pitch range


5.  Was membership in treatment maintained throughout the study?  Yes. Initially a seventh participant was identified but was excluded from this report due to severe hearing loss and presence of a cochlear implant.

a.  If there was more than one participant, did at least 80% of the participants remain in the study?  Yes

b.  Were any data removed from the study?  No 


6.  Did the design include appropriate controls? No, these were case studies, 

a.  Were preintervention data collected on all behaviors?  No. Participant satisfaction (Outcome #3) was not pretested but Outcomes #1 and 2 were pretested.

b.  Did probes/intervention data include untrained data?  Yes

c.  Did probes/intervention data include trained data?  No

d.  Was the data collection continuous?  No

e.  Were different treatment counterbalanced or randomized?  Not Applicable


7.  Were the outcomes measure appropriate and meaningful?  Yes

a.  The outcomes were:


  OUTCOME #1:  Improved single word intelligibility on the Children’s Speech Intelligibility Measure (CSIM)

  OUTCOME #2:  Improved intelligibility of connected speech describing pictures of Renfrew’s Bus Story


  OUTCOME #3:  Positive participant perception of intervention

  OUCOME #4:  Improve breath control for speech.  (Specific data were not provided for this outcome. Therefore, it will not be discussed further.)

b.  All the outcomes were subjective.

c.  None of the outcomes were objective.

d.  None of the outcome measures were supported with reliability data. Investigators noted that there was not good agreement among judges but did not provide supporting data.


8.  Results:

a.  Did the target behavior improve when it was treated?  Inconsistent, but even when there were notable difference, none of them were statistically different.

b.   The overall quality of improvement was

•  NOTE: Comparisons were for preintervention (Pre; 3 days of data collection, 3 judges), 1 week post intervention preintervention (Post1; 3 days of data collection, 3 judges), 7 weeks post intervention preintervention (Post7) 3 days of data collection, 3 judges)*


OUTCOME #1:  Improved single word intelligibility on the Children’s Speech Intelligibility Measure (CSIM)

•  Pre vs Post1:  1P (slight); 3P (moderate);  1P (strong); 1P (contraindicated)

 Pre vs. Post7:  3P (slight); 1P  (strong); 2P (ineffective)  

OUTCOME #2:  Improved intelligibility of connected speech describing pictures of Renfrew’s Bus Story

•  Pre vs Post1:  3P (moderate); 2P (ineffective); 1P (contraindicated)

 Pre vs. Post7:  1P (slight); 4P (ineffective); 1P (contraindicated)


OUTCOME #3:  Positive participant perception of intervention–  Investigators only provided descriptions of Ps’ responses following intervention.   Overall, Ps’ claimed that they thought the intervention was useful and indicated they would participate again.  The Ps offered concerns about dosage.

9.  Description of baseline:

a.  Were baseline data provided?  No


10.  What was the magnitude of the treatment effect?  NA


11.  Was information about treatment fidelity adequate?  No


12.  Were maintenance data reported?  Yes. The investigators administered post testing 1 week after treatment and 7 weeks after treatment. No significant differences were noted compared to pretesting. Descriptively, 4 Ps were notably better at the 7 week follow up for single words (Outcome #1) and one P appeared to be notably better in the 7 week follow up for connected speech (Outcome #2).


13.  Were generalization data reported?  No






PURPOSE:  To provide initial support for a systems approach for improving the intelligibility of children with cerebral palsy.

POPULATION:  dysarthria associated with cerebral palsy






OTHER ASPECTS OF LANGUAGE/COMMUNICATION TARGETED:  intelligibility, breath control for speech

DOSAGE:  5 days a week, 5 weeks, 20-30 minute sessions  (for students the number of sessions attended ranged from 15-22)


ADMINISTRATOR:  2 SLP students trained to administer the systems approach.  SLP students alternated in serving as Clinician or Assistant in sessions.




TECHNIQUES:  modeling, reinforcement, specific exercises (practiced 10 times in a block, criterion 9 correct in 3 successive blocks), explanation


1.  C described and discussed with P the importance of optimal breathing and posture/seating.

2.  Using 2 types of simple sentences, C instructed P to being exhaling as he/she initially vocalized at the beginning of the sentence. (There were 5 activities with the purpose of using breath control to modify loudness and mark stress in phrases.)

3. Step 2 was repeated but the target was using breath control to modify loudness and mark stress in connected speech (picture description, picture sequences, story telling).  Four activities were associated with this step.

NOTE:  None of the Ps completed the program in the prescribed timeline.


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