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CTD & PTD Review
Citation preview
Time Delay Procedures for Teaching Students with Autism Spectrum Disorders
Gabriela Walker, Ed. S. Department of Communication Sciences & Special Education - University of GeorgiaDepartment of Educational policy Studies – University of Illinois at Urbana-Champaign
Purpose of the review
Examination of applied research literature in which CTD or PTD procedures were used in teaching students diagnosed with ASD or “autistic-like” behaviors
Acronyms
ASD: Autism Spectrum Disorders
CTD: Constant Time Delay procedure
PTD: Progressive Time Delay procedure
ASD characteristicsImpairments in (DSM – IV TR, 2000):
1. Reciprocal social interaction 2. Verbal and non-verbal
communication 3. Restricted stereotyped behaviors or
interests Other possible signs or impairments:
Imitation Theory of mind Perseveration Overselectivity
ASD characteristics – cont’d
Resistance to change Sensory overarousal or underarousal Distorted sense of time Social judgment Executive functioning Self-stimulatory behaviors Self-injurious behaviors Motivation
Treatment approaches for teaching the ASD population (lit review)
Sign language & total communication Incidental teaching Manipulation of antecedents and
consequences Manipulation of environment Increased social interaction Intensive discrete trial (Lovaas, 1987)
Treatment approaches – cont’d Peer behavior intervention Collateral skills intervention Pivotal response treatment (Koegel &
Koegel, 1999) Psychopharmacological Other: vitamins, minerals, gluten-casein
free diet, auditory integration therapy, cranio-sacral manipulation, secretin, holding therapy, facilitated communication
Time Delay Procedure One of the response prompting procedures
MTL Graduated guidance SLP Time delay
A learning strategy that exerts the most control over students’ interactions with the environment (Wolery & Schuster, 1997)
Time delay procedure A.K.A. prompt delay or delay procedure Touchette (1971) – form discrimination Instructional procedure that
transfers stimulus control from a prompt to a discriminative stimulus
fades on time dimension At least one session at 0-s delay
Natural cue/task direction and controlling prompt are presented simultaneously
Sessions at 0-s and X-s delay
Time delay procedure – cont’d
CTD – delay interval held constant throughout the instructional sessions
PTD - delay interval gradually increased
Delay interval vs. response interval Near errorless learning procedure
(less than 10% errors)
Time delay procedure – cont’d
5 types of possible responses Consequences
reinforcers error correction
Procedural modifications
Time Delay – Procedural modifications
change of reinforcer
session length task difficulty wait training differential
reinforcement shift from CTD
to PTD
addition of attending cues
change of task direction
change in task analysis
equipment adaptation
Time delay procedure – cont’d
Effective & efficient procedure Used
… to teach discrete and chained behaviors
… in different instructional arrangements … with different populations (age,
diagnosis) … when incorporated in instructional
packages
Purpose - reiterated
Evaluate effectiveness of the CTD and PTD procedures for teaching students with ASD
Evaluate efficiency, when possible
Methods Electronic search (ERIC, PsycINFO,
PsycArticles) Ancestral search on JABA and JADD Analysis of references of relevant
articles Criteria for inclusion:
Between Jan 1985 to April 2005 CTD & PTD (0-s delay + X-s delay) Participants with autistic or autistic-
like characteristics
Results ORGANIZATION:
demographic variables procedural parameters outcome measures methodological adequacy
Results
CTD – 10 studies PTD – 12 studies
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 -
Results – Demographic
(CTD - Winterling et al. (1992): 2M & 2F, 17-21)
3640
16
37
0
10
20
30
40
50
CTD PTD
Total partic Partic ASD
Results – Demographic: AGEPreschool: 3-5 yrs.; Elementary: 6-11; Adolescence: 12-18; Adulthood: 21>
06
9
16
33
1 005
101520253035
Preschool Elementary Adolescence Adulthood
CTD PTD
Results – Demographic: IQ Mild: 55-70; Moderate: 40-55; Sev-Prof: <40 (For 6 participants in PTD IQ not specified)
0 1
96
13
17
2
0
5
10
15
20
No Mild Moderate Sev.-Prof.
CTD PTD
Results – Demographic: Diagnoses
CTD 2 studies: DSM III 1 study: clinical interviews by
psychiatrists PTD
4 studies: DSM III-R 1 study: Childhood Autism Rating Scale 1 study: National Society for Autistic
Children
Results – Demographic: Settings
7
3
0
76
3
02468
Classroom Community Clinic-Experimental
room
CTD PTD
Results – Demographic: Instruction
CTD: 8 studies: 1:1 instructional format 2 studies: groups of 3 students
PTD: all 1:1 instructional format
CTD & PTD: Instruction delivered mostly by classroom personnel and university associated staff
Results – Demographic: Behaviors
CTD: 4 discrete & 6 chained PTD: all discrete
CTD: leisure skills (2), shopping (2), self-help (2), social interaction (2), safety (1), numeral identification (1)
PTD: spontaneous speech (8), object identification (1), occupational labels (1), imitation of art activities (1), sight words (1).
Results – Procedural: Attentional cues
CTD 3 studies: general active att. cues 3 studies: specific active att. cues 4 studies: none
PTD 2 studies: general active att. cues 10 studies: none
Results – Procedural: No. of 0-s delay
CTD From 1 to as many as necessary until
100% prompted corrects were recorded Mean # of 0-s delay sessions = 3.4
PTD From 1 to as many as necessary until
100% prompted corrects were recorded for 3 consecutive sessions
Mostly ranged from 1 to 3 sessions
Results – Procedural: No. of delay sessions CTD: 4-s delay (5) & 5-s delay (5) PTD
9 studies: 2-s increment 2 studies: 1-s increment 1 study:0-s: 0.5-s: 1-s & continued with
1-s increment 4 studies reported a criterion for increasing
the delay interval Ceiling: 5-s (1), 6-s (1), 7-s (1), 10-s (9)
Results – Procedural: Controlling Prompts
CTD 8 studies: model (verbal & gestural) Others: physical guidance, full
physical PTD
9 studies: verbal model 3 studies: gestural model & physical
prompt
Results – Procedural: Error Correction
CTD: Interruption of student response Teacher completing the step “NO” & wait for the inter-trial
interval Controlling prompt
Results – Procedural: Error Correction
PTD: “No” & materials removed Time-out of the rest of the inter-
trial interval 5-s or 10-s in-seat time-out No reinforcement Controlling prompt Return to previous delay interval
Results – Procedural:
Reinforcers CTD & PTD Descriptive verbal praise & natural
reinforcer
Frequency of instruction: CTD: average of 1 to 2 sessions per
day PTD: average of 1 session per day
Results – Outcomes: Procedural Modifications
CTD – 4 studies: 1. Task analyses modified, equipment
modified & additional physical assistance added
2. Controlling prompt changed, 0-s delay trials added
3. 0-s delay sessions added 4. Differential reinforcement, massed
trials added, training skipped on one skill (for time reasons)
Results – Outcomes: Procedural Modifications
PTD – 4 studies: 1, 2, and 3. Reinforcer added 4. Massed trials added
Results – Outcomes: Effectiveness
CTD: 14/16 participants with ASD CTD not introduced to 2 participants
PTD 37/37 participants with ASD
Results – Outcomes: Efficiency
Mean Error CTD:
Range from 1.35 to 32.5 Total Mean 9.95%
PTD: Range from .29 to 5.3 Total Mean 2.6%
Results – Outcomes: Efficiency
Transfer of Stimulus Control CTD:
Range from 2 to 17 Mean 5.6
PTD: Range from 2 to 7 Mean 4
Results – Outcomes: Efficiency
9.955.57 4.042.60
05
1015
Error Percentage Transfer of StimulusControl
CTD PTD
Results – Outcomes:Maintenance & Generalization
All behaviors maintained CTD: 9 studies PTD: 9 studies
Generalization across persons, settings, and materials CTD: 9 studies PTD: 10 studies
Results – Outcomes:Treatment Comparisons
Ault et al.,
1988
Mean sessions Error percentage
CTD 9.1 10.75
SLP 3.7 11.6
Godby et al., 1987
No. of sessions
Error percentage
PTD 120 (- 6 hrs.) 4.5
SLP 141 13
Results – Outcomes:Treatment Comparisons
Heckaman et al.,
1998
Mean sessions
No. of errors
PTD - 47
LTM - 609
Matson et al., 1993
No. of sessions
Error percentage
PTD 47.3 -
Visual Fading
56.7 -
Results – Methodological: Experimental Designs
All CTD & PTD used single-subject research design (Tawney & Gast, 1984)
MB
MP
Withdrawal
Parallel
AB
Alternating
CTD
5 2 1 1 1 -
PTD 8 2 - 1 - 1
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
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
Results – Methodological:Interobserver Agreement
All point-by-point; Studies: CTD (10); PTD (12) Do independent observers agree?
10010097.9394
95.16800
100
200
CTD 94 97.93 100
PTD 80 95.16 100
Minimum Mean Maximum
Results – Methodological:Procedural Fidelity Intervention implemented as planned? Studies: CTD (6); PTD (5)
100100
89
97.3594.63
97.3
80
90
100
110
CTD 89 97.35 100
PTD 94.63 97.3 100
Minimum Mean Maximum
Results – Methodological:Social Validity
Studies: CTD (5); PTD (5) Gathered on:
Objectives Methods Outcomes
From: caregivers, teachers, school administrators, participants, typical peers
Methods: videotapes, questionnaires, Likert-scales, IEP, typical peers recordings, t-tests.
Discussion: CTD & PTD Effective
with persons identified with autistic symptoms
in various settings in different instructional formats with adult & peer instructors
Treatment packages with CTD also effective
CTD more efficient than SLP PTD more efficient than SLP, LTM, &
Visual Fading
Discussion: CTD & PTD Procedural modifications improved
effectiveness Methodological parameters employed
were adequate in terms of experimental designs used inter-rater agreement procedural reliability social validity
Discussion: CTD vs. PTD
Similar in effectiveness PTD possibly more efficacious than
CTD in terms of moment of transfer of stimulus control error percentage
Limitations of the studies Generalizabilitiy of results
Size of sample Intervention packages Lack of planned generalization
Reported mean percentage of errors is rather high (13.9%)
Inconsistent report of diagnoses and diagnosis criteria (e.g. Asperger)
Inconsistent report on use of medication
Limitations of the present review
Preschoolers may have been missed because of diagnosis specificity
No studies prior to 1985 included All studies included were published
(e.g. no dissertations) Data collected and analyzed by only
one person (no reliability data available)
Conclusions 1. The participants with ASD were in majority:
elementary aged functioning within a Mo range of cognitive
abilities
2. CTD and PTD interventions conducted mainly: by classroom and university staff in classroom and community settings in one-on-one instructional format
3. Skills: discrete > chained
Conclusions4. CTD and PTD:
mean of ~ 2 sessions of 0-s delay
5. CTD: no. of studies 4-s = 5-s delay
6. CTD and PTD: controlling prompts mostly verbal and
gestural models
Conclusions 7. PTD:
mostly 1-s and 2-s increments the highest ceiling of the delay interval at
10-s
8. Error consequence for unprompted errors: the teachers interrupted the response
9. Reinforcer: natural consequence often associated with descriptive verbal
praise
Conclusions 10. Instruction: 1-2 times per day
11. Errors: CTD more (9.95%) than PTD (2.6%)
12. Procedural modifications: described in 4 studies per each procedure modifications were greater in CTD studies
Conclusions 13. Effectiveness: CTD and PTD in
teaching individuals with ASD
14. Transfer of stimulus control: earlier when using PTD (by the 4th
session) than when using the CTD (by the 5.5th session)
15. Maintenance and generalization: all learned behaviors with CTD and PTD
Conclusions 16. Efficiency:
CTD superior to SLP procedure PTD superior to SLP, LTM, and visual
fading procedures;
17. Experimental designs All studies Single-Subject (MB and MP)
Conclusions 18. Inter-rater agreement and
procedural fidelity means: similar and high for both procedures
19. Social validity: collected for almost half of the studies
Further Research More studies on CTD & PTD for teaching
ASD individuals Replications of effective treatment
packages and isolation of intervention variables
More specific data on dx. & dx. criteria Data on medication Data on superimposed conditions Generalization programming Caregivers as trainers – parental
implication in educating their own children