Thomas-Stonell et al. (1991)


Single Subject Designs


SOURCE:  Thomas-Stonell, N., McClean, M., & Hunt, E. (1991). Evaluation of the SpeechViewer computer-based speech training system with neurologically impaired individuals. Journal of Speech-Language Pathology and Audiology, 15 (4), 47-56.  


REVIEWERS:  Amy Anderson (Minnesota State University, Mankato), Jessica Jones (Minnesota State University, Mankato), pmh


DATE:  2009



TAKE AWAY:  This research provides moderate support for a computer based intervention for the improvement of rate and intelligibility in one child and two adolescents with neurological impairment.  



1.  What was the focus of the research? Clinical Research


2.  What type of evidence was identified?                              

a.  What type of single subject design was used?  Single Subject Experimental Design with Specific Client – Multiple Baseline

b.  What was the level of support associated with the type of evidence? 

Level = A-                                                        


3.  Was phase of treatment concealed?                                 

a.  from participants?  No                             

b.  from clinicians?  No                                 

c.  from data analyzers?  No                        


4.  Were the participants adequately described?  Yes

a.  How many participants were involved in the study?  3

b.  The following characteristics were described?

•  age:  18, 17, 5

•  gender:  2m, 1f                            

•  language:  all 3 had participated in formal education in English (Canadian)

•  cognition:  all had some insight regarding intervention

•  etiology:  2 closed head injury (the adolescents, P1 & 2), 1 myotonic dystrophy (P3)

•  post onset:  P1 & 2—6 months; P3–NA

c.  Were the communication problems adequately described?  Yes

•  The disorder type was  dysarthria  

Other aspects of communication:

•  hearing:  all WNL

•  severity of dysarthria:  P1 = NA, P2 = mild, P3 = severe

•  comprehension:  all able to follow directions

•  intelligibility, pre therapy:

–  P1 – single word = 78%; sentence = 95.9%; average = 87%

–  P2 – single word = 92%; sentence = 89%; average = 90.5%

–  P3 – single word = 28%

•  voice quality:  breathy (P1, P2), intermittent aphonic with laryngeal tension and some glottal fry (P3)

•  breath support:  reduced (P1, P3)

•  aerodynamic testing:  reduced oral pressure and elevated airflow rate (P1); WNL oral pressure and elevated airflow rate (P2, P3); difficulty coordinating respiration and larynx during syllable repetition (P3)l

•  prosody:

–  reduced pitch (P1, P2)

  –  reduced intensity (P1, P2)

  –  variable intensity (P3)

  –  equalized stress (scanning speech) (P1)

  –  reduced rate (P1, P3)

  –  fast rate (P2)

  –  oral reading  and conversation = slurred, imprecise, hesitation, interjections, revisions (P2)

•  articulation

  –  accurate single words and in conversational speech some consonant cluster reductions and final consonant deletion (P1)

  –  imprecise consonants (P2)

  –  oral reading  and conversation = slurred, imprecise (P2)

  –  developmental errors (P3)

  –  in connected speech tended to produce continuous voicing across words


5.  Was membership in treatment maintained throughout the study?  Yes

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?  Yes

a.  Were baseline/preintervention data collected on all intervention behaviors? Yes

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

Intervention session outcomes:

  OUTCOME #1:  Improved voice onset time (VOT)

  OUTCOME #2:  Improved vowel duration

  OUTCOME #3:  Improved sentence duration

Computerized Assessment of Intelligibility of Dysarthric Speech (CAIDS measures; Yorkston et al., 1984)

  OUTCOME #4:  Improved intelligibility

  OUTCOME #5:  Improved speaking rate

b.  Outcome #4 was subjective.                                                             

c.  Outcomes #1, 2, 3, and 5 were objective.                                                   

d.  No reliability data were provided.


8.  Results:

a.  Did the target behavior improve when it was treated?  Inconsistent

b.  The overall quality of improvement for each of t was as strong, moderate, limited, ineffective, contraindicated(The numbers should match the numbers in item 7a.)

 Intervention session outcomes:

OUTCOME #1:  Improved voice onset time (VOT)—moderate for 2Ps, ineffective for 1P

  OUTCOME #2:  Improved vowel duration—  moderate for 2Ps; strong for 1P;

  OUTCOME #3:  Improved sentence duration – moderate for 2Ps, limited for 1P

Computerized Assessment of Intelligibility of Dysarthric Speech (CAIDS; Yorkston et al., 1984) outcomes

OUTCOME #4:  Improved intelligibility—strong for 2Ps, moderate for 1P

  OUTCOME #5:  Improved speaking rate—strong for 2Ps, ineffective for 1P

9.  Description of baseline:

a.  Were baseline data provided?  Yes

NOTE:  In these multiple baseline designs, the order of targeted intervention session outcomes varied (i.e., different outcomes were first, second, or third).  Accordingly, there is a range of data points for each outcome because because of the different orders.

Intervention session outcomes:

OUTCOME #1:  Improved voice onset time (VOT)—5-7

OUTCOME #2:  Improved vowel duration—4-12

OUTCOME #3:  Improved sentence duration—4-12

Computerized Assessment of Intelligibility of Dysarthric Speech (CAIDS measures; Yorkston et al., 1984)

OUTCOME #4:  Improved intelligibility–1

OUTCOME #5:  Improved speaking rate–1

b.  Was baseline low (or high, as appropriate) and stable?

 Intervention session outcomes:

OUTCOME #1:  Improved voice onset time (VOT)—high  and nonstable (1P)

OUTCOME #2:  Improved vowel duration—moderate and moderately stable (1P)

OUTCOME #3:  Improved sentence duration—variable and unstable (1P)

Computerized Assessment of Intelligibility of Dysarthric Speech (CAIDS measures; Yorkston et al., 1984)

OUTCOME #4:  Improved intelligibility –NA

OUTCOME #5:  Improved speaking rate  —NA

c.  What was the percentage of nonoverlapping data (PND)?

NOTE:  Only cited for prosodic intervention targets:

  OUTCOME #2:  Improved vowel duration—68% (P1);  78% (P2); 63% (P3)

OUTCOME #3:  Improved sentence duration—78% (P1); 44% (P2); 75% (P3)

d.  Does inspection of data suggest that the treatment was effective?         

NOTE:  Only cited for prosodic targets”

Intervention session outcomes:

  OUTCOME #2:  Improved vowel duration—questionable effectiveness (P1, P3);  fairly effective (P2);)

OUTCOME #3:  Improved sentence duration—fairly effective (P1, P3); ineffective (P2)


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


11.  Was information about treatment fidelity adequate?  Not Provided


12.  Were maintenance data reported?  Yes. The investigators noted in the discussion that P1 maintained progress for intelligibility and that speaking rate was better than pretraining at the 6 month follow up. At the 16 month follow up, intelligibility had decreased to the pretraining level. The investigators also noted P1 and P3 displayed some generalization to activities of daily living during the study.


13.  Were generalization data reported? Yes, #4 and 5 can be viewed as generalization data.






PURPOSE:  To investigate the effectiveness of computer based interventions for improving prosody, vowels, and intelligibility.

POPULATION:  neurological impairment (adolescents, child)






ELEMENTS OF PROSODY USED AS INTERVENTION (part of independent variable):  vowel duration, sentence duration, rate, pause



DOSAGE:  45 minute sessions, 3 times a weeks, 24-36 sessions




STIMULI:   auditory, visual





•  Although not all of the treatment phases were concerned with prosody, they will be described here because some of the improvements in prosody occurred during nonprosodic treatment phases. The investigators suggested there could be a stabilization factor involved.

VOT Phase

•  Used the following modules of the SpeechViewer:

–  Voicing Onset Awareness:  P moves a train on a screen when he/she produces the onset of a voiced sound. The module provides the time it takes to  move the train through the screen. The target is increased speed of speech which signifies increased laryngeal control.

–  Voicing Skill Building:  C creates a scene with mountains (voiced sounds). C produces vocalization in time with the beginning of a mountain  C gradually moves the mountains closer and closer requiring P to turn his/her voice on and off more rapidly. This requires increased laryngeal control.

–  Pitch and Loudness Patterning:  This phase focuses on the Loudness portion of the module. The program provides feedback about voiced (red) and voiceless (green) sounds. When P produces words beginning with voiceless plosives, P visualizes the voice onset time and notes the amount of green at the beginning of the word.

Vowel Training Phase

 Used the following modules of the SpeechViewer:

–  Spectra Patterning:  C presents a frozen model of a target sound spectrum. P attempts to replicate the vowel and receives live action visual feedback regarding the production. The live action feedback is in a color different from the model and P can manipulate his/her attempts to match the model more closely. The target is to achieve a production close to the model.

–  Vowel Accuracy Skill Building:  C sets up a target accuracy range for the production of a vowel. As P’s accuracy improves, C decreases the accuracy range. The target is consistently accurate production of the vowel.

–  Vowel Contrasting Skill Building:  P moves a cursor through a maze by producing 4 different correct vowels. P learns to alternate between the correct production of different vowels.

Rate Phase

•  The investigator used the Stepping Stones Game (Thomas-Stonell, McClean, & Dolman, 1991) to modify rate. This computer game involved P moving to an island using stepping stones. P produces sentences at a rate designated by C with the space between each stone representing a pause.


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