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