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NAS Conference 2008

NAS Conference 2008. Greg Pasco & Kate Gordon THE EFFECTIVENESS OF PECS STUDY: FINDINGS AND IMPLICATIONS FOR FUTURE RESEARCH. The Effectiveness of PECS Study. 1. PECS: The research context. 2. Evaluations of PECS: What next?. 3. The Effectiveness of PECS Study. 1.

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NAS Conference 2008

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  1. NAS Conference 2008 Greg Pasco & Kate Gordon THE EFFECTIVENESS OF PECS STUDY: FINDINGS AND IMPLICATIONS FOR FUTURE RESEARCH

  2. The Effectiveness of PECS Study 1 PECS: The research context 2 Evaluations of PECS: What next? 3

  3. The Effectiveness of PECS Study 1 • The largest published randomised trial of any psychosocial intervention for children with autism • 84children in17classes • Classes randomly assigned tothreetreatment groups • All children assessed atbaselineandtwo follow-uppoints

  4. Immediate Treatment 2-day PECS workshop Monthly PECS consultation visits Delayed Treatment Approx 2 terms No Treatment The Effectiveness of PECS Study Assessment timetable T1 T2 T3

  5. The Effectiveness of PECS Study Participant characteristics (at T1) Age (y:m)Mean6:10Range3:11 – 10:02 Sex11 girls73 boys Mullen Nonverbal Median23.5InterquartileRange19.0 – 29.5 Age Equiv (m) ADOS Diag score Median16Interquartile Range7 – 22 ADOS Diagnosis75 Autism9 ASD BPVS (Raw) Median1Interquartile Range0 – 11 EOWPVT (Raw) Median0Interquartile Range0 – 8.5

  6. The Effectiveness of PECS Study Outcome measures Rates of:Initiations PECS use Speech observed in children’s snack times ADOSCommunication& ReciprocalSocial InteractionDomain scores BPVSandEOWPVTraw scores

  7. The Effectiveness of PECS Study COSMIC Classroom Observation Schedule to Measure Intentional Communication (COSMIC:Pasco et al, 2008) All children videoed for15 minutesduringsnack All videos rated by GP and KG usingCOSMIC Each interaction coded according toForm, Function,Spontaneity,Communication Partner

  8. The Effectiveness of PECS Study COSMIC Outcomes PECS use: Distribution verypositively skewed, so datatransformedintoordinal categories

  9. The Effectiveness of PECS Study Analysis Hierarchical Ordinal Regression: Accounted for the fact that data wereclusteredby individual and by class, and in atime sequence Controlled for a number of baseline variables –Age,Mullen NVDQ,ADOS Language Level Tested forimmediate treatment effectsand maintenance(for ITG)

  10. Immediate Treatment Maintenance of treatment effects Delayed Treatment Immediate treatment effects No Treatment The Effectiveness of PECS Study Hierarchical ordinal regression T1 T2 T3

  11. The Effectiveness of PECS Study Results COSMIC DVs: Initiations Immediate: Odds Ratio2.73(p<.05) Not maintained at 10-month follow-up: OR1.08(p=.91) PECS Use Immediate: OR3.90(p<.001) Not maintained at 10-month follow-up: OR1.56(p=.48) Speech Immediate: OR1.10(p=.83)

  12. The Effectiveness of PECS Study Results Other DVs: ADOS Communication Immediate: OR0.52(p=.10) ADOS RSI Immediate: OR0.55(p=.13) But, delayed treatment effect (?) OR0.28(p<.05) EOWPVTImmediate: OR1.01(p=.87) BPVSImmediate: OR1.54(p=.44)

  13. The Effectiveness of PECS Study Results What does this mean? Immediately following the intervention period, children in the treatment groups were more than2½ timesmore likelyto be in ahigher initiationordinalcategory, and nearly4 times more likelyto be in ahigher PECS use ordinal category, than they were at other time points, and in comparison to the NTG at all time points. These effects werenot maintained10 months after the intervention period ceased

  14. The Effectiveness of PECS Study Results And… There were no benefits for children’s rates ofspeech Immediate treatment effectsdid not generalise to communication behaviours observed in astructured context, nor in relation to scores onstandardised testsof receptive and expressive vocabulary There may be a longer-term benefit for children’sreciprocal social interactionskills

  15. The Effectiveness of PECS Study Discussion Clinically meaningful? Pre- to post-treatment: from~15to~26initiationsper hour and from~12to~40interactions involvingPECSper hour These reflect changes in children’severydayuse of communicationin the classroom Does lack of change inspeechreflectdurationorintensityof intervention orparticipants’ skills?

  16. The Effectiveness of PECS Study Discussion Strengths of study Randomisation Ecologically valid measurement of communication ‘Real World’ context Number of participants Analysis Intention to treat protocol

  17. The Effectiveness of PECS Study Discussion Limitations of study Observations restricted to snack times No measure of treatment fidelity Raters not blinded to treatment status, time points, etc.

  18. The Effectiveness of PECS Study Paper Howlin, Gordon, Pasco, Wade & Charman (2007) The effectiveness of Picture Exchange Communication System (PECS) training for teachers of children with autism: A pragmatic, group randomised controlled trial Journal of Child Psychology & Psychiatry, 48(5), 473-481.

  19. PECS: The research context 2 Evaluations of PECS The 4- (or 5-) step/phase model for establishing the effectiveness of an intervention, based on established medical research model e.g. Robey & Schultz (1998) Chambless & Hollen (1998) Flay et al (2005) Smith et al (2007)

  20. Evaluations of PECS The 4-Phase Model • Novel intervention applied to asmallsample, usuallywithout controls. Practice is refined. Does the intervention help, or lead to adverse outcomes? • Formulation and standardisation of intervention (i.e. developing amanual),validating measurement instruments, assessing factors predicting treatment response, optimal ‘dosage’

  21. Evaluations of PECS The 4-Phase Model • Efficacystudies. Large samples, RCTs, treatment fidelity measurement, independent replication. Intervention under ‘ideal’ conditions, often implemented by experts • Effectivenessstudies. Large samples, controls and randomisation (but not necessarily). Intervention underReal Worldconditions, implemented by ‘typical’ professional – teacher, SLT, etc.

  22. Evaluations of PECS The 4-Phase Model 1 4 2 3

  23. Evaluations of PECS Phase 1 • Bondy & Frost (1993) • Bondy & Frost (1994) • Relatively large samples. Descriptive accounts of change

  24. Evaluations of PECS Phase 2 • Manuals • Frost & Bondy (1994) – First manual • Frost & Bondy (2002) – Second manual

  25. Evaluations of PECS Phase 3 • Single case/Case series • Webb (2000): N = 6 (5 with ASD). Increases in use of PECS and speech for all children, plus increases on Derbyshire DTC • Charlop-Christie et al (2002): N = 3. Multiple baseline design. All children learned to use PECS to Phase 6 and showed increases in speech

  26. Evaluations of PECS Phase 3 • Service evaluations • Schwartz, Garfinkle & Bauer (1998): N = 31 (16 with autism or PDD-NOS). Children used PECS to communicate with adults and peers by 14 months. N = 18 (10 with autism). 8 developed spontaneous speech over 1 year (No breakdown by diagnosis)

  27. Evaluations of PECS Phase 3 • Controlled studies • Carr & Felce (2007a): N = 41. Researchers delivered 15 hours of PECS training to children, up to Phase 3. Observation of child-adult interactions. Increases in child-adult initiations and adult-child initiations with opportunity for child response relative to controls. Some evidence of increase in speech(Carr & Felce, 2006b)

  28. Evaluations of PECS Phase 3 • RCTs • Yoder & Stone (2006 a & b): N = 36. Comparison of PECS and RPMT (Responsive Education and Prelinguistic Milieu Teaching). RPMT better at facilitating turn-taking and joint attention, PECS better for requests and spontaneous speech (& spoken vocab). Rigorous methodology, generalisation measures, predictors of response to treatment (conditional treatment effects)

  29. Evaluations of PECS Phase 4 • Uncontrolled study • Magiati & Howlin (2003): N = 34. Pre-/Post-intervention. Rapid acquisition of PECS, increases in PECS vocabulary, and frequency of PECS use. Relied on report data • RCT • Howlin et al (2007)

  30. PECS: The research context “Does PECS work?” • Criteria: (see Rogers & Vismara (2008) re. early interventions) • Chambless et al (1996 & 1998) • Well-established: • Manual • PLUS 2 independent well-designed studies showing treatment > placebo or = a proven treatment • OR 9+ single-subject studies with strong designs and comparison to an alternative treatment

  31. PECS: The research context “Does PECS work?” • Probably efficacious: • Clearly specified participant groups (manual preferable but not required) • PLUS 2 studies showing better outcomes than a no treatment control group • OR 2 strong group studies by the same investigator treatment > placebo or = a proven treatment • OR3+ single-subject studies with strong designs and comparison to an alternative treatment

  32. PECS: The research context “Does PECS work?” • According to the Chambless criteria, PECS can probably be described as “well-established”, although note that studies have incorporated varied outcome measures (acquisition of PECS, use of speech, spontaneity…), different settings and ages of participants

  33. “very strong, positive evidence”

  34. Evaluations of PECS: What next? 3 • PECS is currently the only autism-specific psychosocial intervention to have been tested to theeffectivenessphase byRCT • Not surprisingly, PECS appears to facilitatespontaneous requesting, and may also have additional benefits fordeveloping speech

  35. Evaluations of PECS What next? • Clearly PECS is an appropriate intervention for nonverbal children with autism, although (as with other interventions) there is limited evidence to saywhich childrenwill benefit most • Further well-conducted independent studies (small & large scale) are required to establishefficacy and effectiveness in relation to differentsettings,agesanddiagnoses

  36. Evaluations of PECS What next? • More evidence is required as to what are the most effective ways of providingtraining&consultancyto developbest practicein everyday settings and ensuremaintenanceof benefits for children

  37. Evaluations of PECS What are the prerequisites to becoming a successful PECS user? Christina Tohill, SLT:MSc Project. 23 initially nonverbal children who received intensive PECS training in special school setting. 16 made significant progress, whilst 7 did not move beyond Phase 3 (i.e. unable to discriminate). Allchildren hadPEP-Rassessments around time of introduction to PECS What distinguished thesuccessfulfrom theunsuccessfulchildren?

  38. Evaluations of PECS What are the prerequisites to becoming a successful PECS user? Nonverbal skills? Mann-Whitney U = 53.0 (p=.82)

  39. Evaluations of PECS What are the prerequisites to becoming a successful PECS user? Perception skills? Mann-Whitney U = 7.0 (p=.001)

  40. Evaluations of PECS What are the prerequisites to becoming a successful PECS user? Overall cognitive skills? Mann-Whitney U = 0.5 (p<.001) We don’t know what this score on PEP-R equates to in terms of“actual” cognitive ability Need to do aprospectivestudy to test this out further

  41. Acknowledgements • We would like to thank all the children who participated in the Effectiveness of PECS Study, their parents and teachers • Sue Baker and Teresa Webb and colleagues at Pyramid • The study was funded by the Three Guineas Trust

  42. Thank you

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