Teaching Autism: CTD & PTD Review


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CTD & PTD Review

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  • Teaching Autism: CTD & PTD Review

    1. 1. Time Delay Procedures for Teaching Students with Autism Spectrum Disorders Gabriela Walker, Ed. S. Department of Communication Sciences & Special Education - University of Georgia Department of Educational policy Studies – University of Illinois at Urbana-Champaign
    2. 2. Purpose of the review <ul><li>Examination of applied research literature in which CTD or PTD procedures were used in teaching students diagnosed with ASD or “autistic-like” behaviors </li></ul>
    3. 3. Acronyms <ul><li>ASD: Autism Spectrum Disorders </li></ul><ul><li>CTD: Constant Time Delay procedure </li></ul><ul><li>PTD: Progressive Time Delay procedure </li></ul>
    4. 4. ASD characteristics <ul><li>Impairments in (DSM – IV TR, 2000): </li></ul><ul><ul><li>1. Reciprocal social interaction </li></ul></ul><ul><ul><li>2. Verbal and non-verbal communication </li></ul></ul><ul><ul><li>3. Restricted stereotyped behaviors or interests </li></ul></ul><ul><ul><li>Other possible signs or impairments: </li></ul></ul><ul><ul><ul><li>Imitation </li></ul></ul></ul><ul><ul><ul><li>Theory of mind </li></ul></ul></ul><ul><ul><ul><li>Perseveration </li></ul></ul></ul><ul><ul><ul><li>Overselectivity </li></ul></ul></ul>
    5. 5. ASD characteristics – cont’d <ul><ul><li>Resistance to change </li></ul></ul><ul><ul><li>Sensory overarousal or underarousal </li></ul></ul><ul><ul><li>Distorted sense of time </li></ul></ul><ul><ul><li>Social judgment </li></ul></ul><ul><ul><li>Executive functioning </li></ul></ul><ul><ul><li>Self-stimulatory behaviors </li></ul></ul><ul><ul><li>Self-injurious behaviors </li></ul></ul><ul><ul><li>Motivation </li></ul></ul>
    6. 6. Treatment approaches for teaching the ASD population (lit review) <ul><li>Sign language & total communication </li></ul><ul><li>Incidental teaching </li></ul><ul><li>Manipulation of antecedents and consequences </li></ul><ul><li>Manipulation of environment </li></ul><ul><li>Increased social interaction </li></ul><ul><li>Intensive discrete trial (Lovaas, 1987) </li></ul>
    7. 7. Treatment approaches – cont’d <ul><li>Peer behavior intervention </li></ul><ul><li>Collateral skills intervention </li></ul><ul><li>Pivotal response treatment (Koegel & Koegel, 1999) </li></ul><ul><li>Psychopharmacological </li></ul><ul><li>Other: vitamins, minerals, gluten-casein free diet, auditory integration therapy, cranio-sacral manipulation, secretin, holding therapy, facilitated communication </li></ul>
    8. 8. Time Delay Procedure <ul><li>One of the response prompting procedures </li></ul><ul><ul><li>MTL </li></ul></ul><ul><ul><li>Graduated guidance </li></ul></ul><ul><ul><li>SLP </li></ul></ul><ul><ul><li>Time delay </li></ul></ul><ul><li>A learning strategy that exerts the most control over students’ interactions with the environment (Wolery & Schuster, 1997) </li></ul>
    9. 9. Time delay procedure <ul><li>A.K.A. prompt delay or delay procedure </li></ul><ul><li>Touchette (1971) – form discrimination </li></ul><ul><li>Instructional procedure that </li></ul><ul><ul><li>transfers stimulus control from a prompt to a discriminative stimulus </li></ul></ul><ul><ul><li>fades on time dimension </li></ul></ul><ul><li>At least one session at 0-s delay </li></ul><ul><ul><li>Natural cue/task direction and controlling prompt are presented simultaneously </li></ul></ul><ul><li>Sessions at 0-s and X-s delay </li></ul>
    10. 10. Time delay procedure – cont’d <ul><li>CTD – delay interval held constant throughout the instructional sessions </li></ul><ul><li>PTD - delay interval gradually increased </li></ul><ul><li>Delay interval vs. response interval </li></ul><ul><li>Near errorless learning procedure (less than 10% errors) </li></ul>
    11. 11. Time delay procedure – cont’d <ul><li>5 types of possible responses </li></ul><ul><li>Consequences </li></ul><ul><ul><li>reinforcers </li></ul></ul><ul><ul><li>error correction </li></ul></ul><ul><li>Procedural modifications </li></ul>
    12. 12. Time Delay – Procedural modifications <ul><ul><li>change of reinforcer </li></ul></ul><ul><ul><li>session length </li></ul></ul><ul><ul><li>task difficulty </li></ul></ul><ul><ul><li>wait training </li></ul></ul><ul><ul><li>differential reinforcement </li></ul></ul><ul><ul><li>shift from CTD to PTD </li></ul></ul><ul><ul><li>addition of attending cues </li></ul></ul><ul><ul><li>change of task direction </li></ul></ul><ul><ul><li>change in task analysis </li></ul></ul><ul><ul><li>equipment adaptation </li></ul></ul>
    13. 13. Time delay procedure – cont’d <ul><li>Effective & efficient procedure </li></ul><ul><li>Used </li></ul><ul><ul><li>… to teach discrete and chained behaviors </li></ul></ul><ul><ul><li>… in different instructional arrangements </li></ul></ul><ul><ul><li>… with different populations (age, diagnosis) </li></ul></ul><ul><ul><li>… when incorporated in instructional packages </li></ul></ul>
    14. 14. Purpose - reiterated <ul><li>Evaluate effectiveness of the CTD and PTD procedures for teaching students with ASD </li></ul><ul><li>Evaluate efficiency, when possible </li></ul>
    15. 15. Methods <ul><li>Electronic search (ERIC, PsycINFO, PsycArticles) </li></ul><ul><li>Ancestral search on JABA and JADD </li></ul><ul><li>Analysis of references of relevant articles </li></ul><ul><li>Criteria for inclusion: </li></ul><ul><ul><li>Between Jan 1985 to April 2005 </li></ul></ul><ul><ul><li>CTD & PTD (0-s delay + X-s delay) </li></ul></ul><ul><ul><li>Participants with autistic or autistic-like characteristics </li></ul></ul>
    16. 16. Results <ul><li>ORGANIZATION: </li></ul><ul><ul><li>demographic variables </li></ul></ul><ul><ul><li>procedural parameters </li></ul></ul><ul><ul><li>outcome measures </li></ul></ul><ul><ul><li>methodological adequacy </li></ul></ul>
    17. 17. Results <ul><li>CTD – 10 studies </li></ul><ul><li>PTD – 12 studies </li></ul>  Journal CTD PTD J. of Applied Behavior Analysis 1 7 J. of Autism and Developmental Disorders 1 - J. of Behavioral Education - 2 J. of Developmental and Physical Disabilities 2 - Early Childhood Research Quarterly - 1 Education and Training in Mental Retardation and Developmental Disabilities 2 - Education and Treatment of Children - 1 Exceptional Children 1 - Preventing School Failure 1 - Research in Developmental Disabilities - 1 J. of School Psychology 1 - J. of Special Education Technology 1 -
    18. 18. Results – Demographic <ul><li>(CTD - Winterling et al. (1992): 2M & 2F, 17-21) </li></ul>
    19. 19. Results – Demographic: AGE Preschool: 3-5 yrs.; Elementary: 6-11; Adolescence: 12-18; Adulthood: 21>
    20. 20. Results – Demographic: IQ <ul><li>Mild: 55-70; Moderate: 40-55; Sev-Prof: <40 </li></ul><ul><li>(For 6 participants in PTD IQ not specified) </li></ul>
    21. 21. Results – Demographic: Diagnoses <ul><li>CTD </li></ul><ul><ul><li>2 studies: DSM III </li></ul></ul><ul><ul><li>1 study: clinical interviews by psychiatrists </li></ul></ul><ul><li>PTD </li></ul><ul><ul><li>4 studies: DSM III-R </li></ul></ul><ul><ul><li>1 study: Childhood Autism Rating Scale </li></ul></ul><ul><ul><li>1 study: National Society for Autistic Children </li></ul></ul>
    22. 22. Results – Demographic: Settings
    23. 23. Results – Demographic: Instruction <ul><li>CTD: </li></ul><ul><ul><li>8 studies: 1:1 instructional format </li></ul></ul><ul><ul><li>2 studies: groups of 3 students </li></ul></ul><ul><li>PTD: all 1:1 instructional format </li></ul><ul><li>CTD & PTD: Instruction delivered mostly by classroom personnel and university associated staff </li></ul>
    24. 24. Results – Demographic: Behaviors <ul><li>CTD: 4 discrete & 6 chained </li></ul><ul><li>PTD: all discrete </li></ul><ul><li>CTD: leisure skills (2), shopping (2), self-help (2), social interaction (2), safety (1), numeral identification (1) </li></ul><ul><li>PTD: spontaneous speech (8), object identification (1), occupational labels (1), imitation of art activities (1), sight words (1). </li></ul>
    25. 25. Results – Procedural: Attentional cues <ul><li>CTD </li></ul><ul><ul><li>3 studies: general active att. cues </li></ul></ul><ul><ul><li>3 studies: specific active att. cues </li></ul></ul><ul><ul><li>4 studies: none </li></ul></ul><ul><li>PTD </li></ul><ul><ul><li>2 studies: general active att. cues </li></ul></ul><ul><ul><li>10 studies: none </li></ul></ul>
    26. 26. Results – Procedural: No. of 0-s delay <ul><li>CTD </li></ul><ul><ul><li>From 1 to as many as necessary until 100% prompted corrects were recorded </li></ul></ul><ul><ul><li>Mean # of 0-s delay sessions = 3.4 </li></ul></ul><ul><li>PTD </li></ul><ul><ul><li>From 1 to as many as necessary until 100% prompted corrects were recorded for 3 consecutive sessions </li></ul></ul><ul><ul><li>Mostly ranged from 1 to 3 sessions </li></ul></ul>
    27. 27. Results – Procedural: No. of delay sessions <ul><li>CTD: 4-s delay (5) & 5-s delay (5) </li></ul><ul><li>PTD </li></ul><ul><ul><li>9 studies: 2-s increment </li></ul></ul><ul><ul><li>2 studies: 1-s increment </li></ul></ul><ul><ul><li>1 study:0-s: 0.5-s: 1-s & continued with 1-s increment </li></ul></ul><ul><ul><ul><li>4 studies reported a criterion for increasing the delay interval </li></ul></ul></ul><ul><ul><li>Ceiling: 5-s (1), 6-s (1), 7-s (1), 10-s (9) </li></ul></ul>
    28. 28. Results – Procedural: Controlling Prompts <ul><li>CTD </li></ul><ul><ul><li>8 studies: model (verbal & gestural) </li></ul></ul><ul><ul><li>Others: physical guidance, full physical </li></ul></ul><ul><li>PTD </li></ul><ul><ul><li>9 studies: verbal model </li></ul></ul><ul><ul><li>3 studies: gestural model & physical prompt </li></ul></ul>
    29. 29. Results – Procedural: Error Correction <ul><li>CTD: </li></ul><ul><ul><li>Interruption of student response </li></ul></ul><ul><ul><li>Teacher completing the step </li></ul></ul><ul><ul><li>“ NO” & wait for the inter-trial interval </li></ul></ul><ul><ul><li>Controlling prompt </li></ul></ul>
    30. 30. Results – Procedural: Error Correction <ul><li>PTD: </li></ul><ul><ul><li>“ No” & materials removed </li></ul></ul><ul><ul><li>Time-out of the rest of the inter-trial interval </li></ul></ul><ul><ul><li>5-s or 10-s in-seat time-out </li></ul></ul><ul><ul><li>No reinforcement </li></ul></ul><ul><ul><li>Controlling prompt </li></ul></ul><ul><ul><li>Return to previous delay interval </li></ul></ul>
    31. 31. Results – Procedural: <ul><li>Reinforcers CTD & PTD </li></ul><ul><ul><li>Descriptive verbal praise & natural reinforcer </li></ul></ul><ul><li>Frequency of instruction: </li></ul><ul><ul><li>CTD: average of 1 to 2 sessions per day </li></ul></ul><ul><ul><li>PTD: average of 1 session per day </li></ul></ul>
    32. 32. Results – Outcomes: Procedural Modifications <ul><li>CTD – 4 studies: </li></ul><ul><ul><li>1. Task analyses modified, equipment modified & additional physical assistance added </li></ul></ul><ul><ul><li>2. Controlling prompt changed, 0-s delay trials added </li></ul></ul><ul><ul><li>3. 0-s delay sessions added </li></ul></ul><ul><ul><li>4. Differential reinforcement, massed trials added, training skipped on one skill (for time reasons) </li></ul></ul>
    33. 33. Results – Outcomes: Procedural Modifications <ul><li>PTD – 4 studies: </li></ul><ul><ul><li>1, 2, and 3. Reinforcer added </li></ul></ul><ul><ul><li>4. Massed trials added </li></ul></ul>
    34. 34. Results – Outcomes: Effectiveness <ul><li>CTD: </li></ul><ul><ul><li>14/16 participants with ASD </li></ul></ul><ul><ul><li>CTD not introduced to 2 participants </li></ul></ul><ul><li>PTD </li></ul><ul><ul><li>37/37 participants with ASD </li></ul></ul>
    35. 35. Results – Outcomes: Efficiency <ul><li>Mean Error </li></ul><ul><li>CTD: </li></ul><ul><ul><li>Range from 1.35 to 32.5 </li></ul></ul><ul><ul><li>Total Mean 9.95% </li></ul></ul><ul><li>PTD: </li></ul><ul><ul><li>Range from .29 to 5.3 </li></ul></ul><ul><ul><li>Total Mean 2.6% </li></ul></ul>
    36. 36. Results – Outcomes: Efficiency <ul><li>Transfer of Stimulus Control </li></ul><ul><li>CTD: </li></ul><ul><ul><li>Range from 2 to 17 </li></ul></ul><ul><ul><li>Mean 5.6 </li></ul></ul><ul><li>PTD: </li></ul><ul><ul><li>Range from 2 to 7 </li></ul></ul><ul><ul><li>Mean 4 </li></ul></ul>
    37. 37. Results – Outcomes: Efficiency
    38. 38. Results – Outcomes: Maintenance & Generalization <ul><li>All behaviors maintained </li></ul><ul><ul><li>CTD: 9 studies </li></ul></ul><ul><ul><li>PTD: 9 studies </li></ul></ul><ul><li>Generalization across persons, settings, and materials </li></ul><ul><ul><li>CTD: 9 studies </li></ul></ul><ul><ul><li>PTD: 10 studies </li></ul></ul>
    39. 39. Results – Outcomes: Treatment Comparisons 11.6 3.7 SLP 10.75 9.1 CTD Error percentage Mean sessions Ault et al., 1988 13 141 SLP 4.5 120 (- 6 hrs.) PTD Error percentage No. of sessions Godby et al., 1987
    40. 40. Results – Outcomes: Treatment Comparisons 609 - LTM 47 - PTD No. of errors Mean sessions Heckaman et al., 1998 - 56.7 Visual Fading - 47.3 PTD Error percentage No. of sessions Matson et al., 1993
    41. 41. Results – Methodological: Experimental Designs <ul><li>All CTD & PTD used single-subject research design (Tawney & Gast, 1984) </li></ul>1 - 1 - 2 8 PTD - 1 1 1 2 5 CTD Alternating AB Parallel Withdrawal MP MB
    42. 42. Dipipi, C. M., Jitendra, A. K., & Miller, J. A. (2001). Reducing repetitive speech: Effects of strategy instruction. Preventing School Failure , 45 , 177-181. 1.Baseline; 2.Time delay; 3.Self-recording+DRO; 4.Maintenance 1 2 3 4
    43. 43. Wall, M. E. & Gast, D. L. (1997). Caregivers’ use of constant time delay to teach leisure skills to adolescents or young adults with moderate or severe intellectual disabilities. Education and Training in Mental Retardation and Developmental Disabilities , 340-356
    44. 44. Results – Methodological: Interobserver Agreement <ul><li>All point-by-point; Studies: CTD (10); PTD (12) </li></ul><ul><li>Do independent observers agree? </li></ul>
    45. 45. Results – Methodological: Procedural Fidelity <ul><li>Intervention implemented as planned? </li></ul><ul><li>Studies: CTD (6); PTD (5) </li></ul>
    46. 46. Results – Methodological: Social Validity <ul><li>Studies: CTD (5); PTD (5) </li></ul><ul><li>Gathered on: </li></ul><ul><ul><li>Objectives </li></ul></ul><ul><ul><li>Methods </li></ul></ul><ul><ul><li>Outcomes </li></ul></ul><ul><li>From: caregivers, teachers, school administrators, participants, typical peers </li></ul><ul><li>Methods: videotapes, questionnaires, Likert-scales, IEP, typical peers recordings, t-tests. </li></ul>
    47. 47. Discussion: CTD & PTD <ul><li>Effective </li></ul><ul><ul><li>with persons identified with autistic symptoms </li></ul></ul><ul><ul><li>in various settings </li></ul></ul><ul><ul><li>in different instructional formats </li></ul></ul><ul><ul><li>with adult & peer instructors </li></ul></ul><ul><li>Treatment packages with CTD also effective </li></ul><ul><li>CTD more efficient than SLP </li></ul><ul><li>PTD more efficient than SLP, LTM, & Visual Fading </li></ul>
    48. 48. Discussion: CTD & PTD <ul><li>Procedural modifications improved effectiveness </li></ul><ul><li>Methodological parameters employed were adequate in terms of </li></ul><ul><ul><li>experimental designs used </li></ul></ul><ul><ul><li>inter-rater agreement </li></ul></ul><ul><ul><li>procedural reliability </li></ul></ul><ul><ul><li>social validity </li></ul></ul>
    49. 49. Discussion: CTD vs. PTD <ul><li>Similar in effectiveness </li></ul><ul><li>PTD possibly more efficacious than CTD in terms of </li></ul><ul><ul><li>moment of transfer of stimulus control </li></ul></ul><ul><ul><li>error percentage </li></ul></ul>
    50. 50. Limitations of the studies <ul><li>Generalizabilitiy of results </li></ul><ul><ul><li>Size of sample </li></ul></ul><ul><ul><li>Intervention packages </li></ul></ul><ul><ul><li>Lack of planned generalization </li></ul></ul><ul><li>Reported mean percentage of errors is rather high (13.9%) </li></ul><ul><li>Inconsistent report of diagnoses and diagnosis criteria (e.g. Asperger) </li></ul><ul><li>Inconsistent report on use of medication </li></ul>
    51. 51. Limitations of the present review <ul><li>Preschoolers may have been missed because of diagnosis specificity </li></ul><ul><li>No studies prior to 1985 included </li></ul><ul><li>All studies included were published (e.g. no dissertations) </li></ul><ul><li>Data collected and analyzed by only one person (no reliability data available) </li></ul>
    52. 52. Conclusions <ul><li>1. The participants with ASD were in majority: </li></ul><ul><ul><li>elementary aged </li></ul></ul><ul><ul><li>functioning within a Mo range of cognitive abilities </li></ul></ul><ul><li>2. CTD and PTD interventions conducted mainly: </li></ul><ul><ul><li>by classroom and university staff </li></ul></ul><ul><ul><li>in classroom and community settings </li></ul></ul><ul><ul><li>in one-on-one instructional format </li></ul></ul><ul><li>3. Skills: discrete > chained </li></ul>
    53. 53. Conclusions <ul><li>4. CTD and PTD: </li></ul><ul><ul><li>mean of ~ 2 sessions of 0-s delay </li></ul></ul><ul><li>5. CTD: no. of studies 4-s = 5-s delay </li></ul><ul><li>6. CTD and PTD: </li></ul><ul><ul><li>controlling prompts mostly verbal and gestural models </li></ul></ul>
    54. 54. Conclusions <ul><li>7. PTD: </li></ul><ul><ul><li>mostly 1-s and 2-s increments </li></ul></ul><ul><ul><li>the highest ceiling of the delay interval at 10-s </li></ul></ul><ul><li>8. Error consequence for unprompted errors: </li></ul><ul><ul><li>the teachers interrupted the response </li></ul></ul><ul><li>9. Reinforcer: </li></ul><ul><ul><li>natural consequence </li></ul></ul><ul><ul><li>often associated with descriptive verbal praise </li></ul></ul>
    55. 55. Conclusions <ul><li>10. Instruction: 1-2 times per day </li></ul><ul><li>11. Errors: </li></ul><ul><ul><li>CTD more (9.95%) than PTD (2.6%) </li></ul></ul><ul><li>12. Procedural modifications: </li></ul><ul><ul><li>described in 4 studies per each procedure </li></ul></ul><ul><ul><li>modifications were greater in CTD studies </li></ul></ul>
    56. 56. Conclusions <ul><li>13. Effectiveness: CTD and PTD in teaching individuals with ASD </li></ul><ul><li>14. Transfer of stimulus control: </li></ul><ul><ul><li>earlier when using PTD (by the 4 th session) than when using the CTD (by the 5.5 th session) </li></ul></ul><ul><li>15. Maintenance and generalization: </li></ul><ul><ul><li>all learned behaviors with CTD and PTD </li></ul></ul>
    57. 57. Conclusions <ul><li>16. Efficiency: </li></ul><ul><ul><li>CTD superior to SLP procedure </li></ul></ul><ul><ul><li>PTD superior to SLP, LTM, and visual fading procedures; </li></ul></ul><ul><li>17. Experimental designs </li></ul><ul><ul><li>All studies Single-Subject (MB and MP) </li></ul></ul>
    58. 58. Conclusions <ul><li>18. Inter-rater agreement and procedural fidelity means: </li></ul><ul><ul><li>similar and high for both procedures </li></ul></ul><ul><li>19. Social validity: </li></ul><ul><ul><li>collected for almost half of the studies </li></ul></ul>
    59. 59. Further Research <ul><li>More studies on CTD & PTD for teaching ASD individuals </li></ul><ul><li>Replications of effective treatment packages and isolation of intervention variables </li></ul><ul><li>More specific data on dx. & dx. criteria </li></ul><ul><li>Data on medication </li></ul><ul><li>Data on superimposed conditions </li></ul><ul><li>Generalization programming </li></ul><ul><li>Caregivers as trainers – parental implication in educating their own children </li></ul>