The Society for Clinical Child and Adolescent Psychology (SCCAP):

Initiative for Dissemination of Evidence-based Treatments for Childhood and Adolescent

Mental Health Problems

With additional support from Florida International University and The Children’s Trust.

Keynote Evidence-Based Practices for Children with Autism Spectrum Disorders

Tristram Smith, Ph.D. Associate Professor of Pediatrics, Neurodevelopmental &Behavioral Pediatrics

Department of Pediatrics University of Rochester Medical Center

Learning Objectives

1. Importance of evidence-based practice in autism

2. Signs of scientific and pseudoscientific treatments

3. Evidence-based treatments for autism 4. Plausible but under-researched treatments

for autism 5. Controversial treatments for autism 6. State of evidence on discrete trial training 7. Implications of evidence-based practice for

families and service providers

1. Importance of Evidence-based Practice

Importance of Evidence-Based Practice (1)

1940s-1960s: Psychoanalysis (Bettelheim, 1967)

– Techniques turned out to increase challenging behaviors (e.g., Lovaas et al., 1965, JECP)

– Parents were falsely blamed for child’s condition

1970s: Bonding therapy (e.g., Kaufman, 1976, Son Rise)

– Attachment is one aspect of social functioning that is intact in ASD (Rutgers et al., 2004, JCPP)

Importance of Evidence-Based Practice (2) 1980s: Fenfluramine

– Found to be ineffective as an intervention for ASD (e.g., Leventhal et al., 1993, J Neuroscience Clin Neurosci)

– Taken off the market in 1997 because of risk of heart valve disease

1990s: Facilitated Communication – Found to be ineffective as an intervention for ASD

(Mostert, 2001, JADD)

– Associated with false accusations of sexual abuse

1990s: Secretin – Found to be ineffective as an intervention for ASD

(Demichelli et al., 2005; Williams et al., 2005, Cochrane Reports)

– Often considered best studied intervention for autism—many more randomized clinical trials than any other treatment

Importance of Evidence-Based Practice (3)

2000’s – Nonvaccination

Health care organizations expected to eradicate measles from the earth by 2010, but it is now making a comeback because of nonvaccination

12,132 cases in Europe in 2006-7, including 13 deaths

Outbreaks in parts of the US (e.g., San Diego)

– Chelation 3 deaths in 2003-5, including a 5-year-old with

autism who died in the doctor’s office immediately after receiving chelation in Pittsburgh

Importance of Evidence-Based Practices

Research has led to identification of effective interventions

– Behavioral approaches

– Medications in some cases

2. Signs of Scientific and Pseudoscientific Treatments

Evidence-Based Practice

Treatment plans based on three factors:

– Scientific evidence

– Clinical decision about client need

Data collection on client response to intervention

– Family priorities

Scientific methods for testing interventions

Single-case designs

– Each subject serves as his/her own control

– Baseline (no treatment) phase is compared with one or more intervention phases

– Data are collected continuously, yielding many data points for analysis

Peer-reviewed

– Anonymous experts evaluate the report

Single-case designs

Each subject serves as his/her own control

Baseline (no treatment) phase is compared with one or more intervention phases

Data are collected continuously, yielding many data points for analysis

Example of single-case design (from Hoch & Taylor, 2008, JABA)

Group Designs

Random assignment to groups

One group receives treatment; other groups receive no treatment or an alternate treatment

When possible, treatment is double-blind, placebo-controlled (experimenters and participants do not know who is getting treatment and who is not)

Data are for all 101 children (49 assigned to the risperidone group and 52 assigned to the placebo group). Higher scores indicate greater irritability.

Example of Group Design (McCracken et al., 2002, NEJM)

Potential ‘Red Flags:’ Determining the Validity of a Treatment

(Finn et al., 2005, Am J Speech-Language Pathology)

1. Does the evidence rely on personal/anecdotal accounts?

2. Is the Tx approach disconnected from well-established scientific models?

3. Is the Tx untestable or unfalsifiable?

4. Does the Tx remain unchanged even in the face of contradictory evidence?

5. Is the rationale based only on confirming evidence, with disconfirming evidence ignored or minimized?

Defeat Autism Now! http://www.autism.com/treatable/adams_biomed_summary.pdf

This summary generally follows the DAN! philosophy, which involves trying to treat the underlying causes of the symptoms of autism, based on medical testing, scientific research, and clinical experience, with an emphasis on nutritional interventions. Many of the DAN! treatments have been found by listening to parents and physicians.

ARI Survey of Parent Ratings of Treatment

Efficacy Most of the treatments listed on the following pages

were evaluated as part of the Autism Research Institute (ARI) survey of over 23,000 parents on their opinion of the effectiveness of various treatments for children with autism.

18

3. Evidence-Based Treatments

Although ASD is a neurobiological disorder, behavioral and educational interventions are the primary treatments – Applied behavior analysis (ABA) is the best studied of

these treatments

Medications may help some individuals with ASD who also have other specific problems: – Severe disruptive behaviors: Substantial short-term

benefits in most cases, though long-term effects are uncertain

– Severe hyperactivity: modest benefits in some cases – Severe repetitive behaviors, depression, anxiety,

mood swings: possible modest benefits (not well studied)

4. Other Plausible Interventions

Under-researched

Target known problems in ASD and use methods similar to ones that have been studied

Examples: – Teaching and Educating Autistic Children and

the Communicatively Handicapped (TEACCH) Emphasizes structured teaching and environmental

modifications

– Developmental Individual-difference Relationship-based Model (DIR, “Greenspan”) “Floortime”—following the child’s lead and

encouraging communication during play activities

TEACCH

Some uncontrolled case series suggesting gains (Lord & Schopler, 1989, JADD; Mukaddes et al., 2004, Autism)

One quasi-experiment showing possible benefits of home services (Ozonoff & Cathcart, 1998, JADD)

Large well-designed study underway (Odom, Strain)

DIR

Self-published chart reviews – Greenspan & Wieder (1997, JDLD) described gains

in social engagement and creativity – Wieder & Greenspan (2005, JDLD) reported

continuing gains 10-15 years later

Peer-reviewed case series (Solomon et al., 2007, Autism) – 68 children receiving home consultation on DIR (half

day monthly for 8-12 months) – Significant improvement on Functional Emotional

Assessment Scale – 46% described as having good or very good

outcomes

One case study showing better results in ABA (Hilton & Seal, 2007, JADD)

Research ongoing on other developmental treatments

Examples

– Social Communication, Emotion Regulation and Transactional Support (SCERTS) (Wetherby and colleagues)

– Denver Model (incorporating elements of ABA and developmental approaches) (Rogers and colleagues)

– Interpersonal synchrony (Landa)

5. Controversial and Alternative Treatments

Many anecdotal reports of effectiveness

Do not target known problems in ASD or use established methods

Have not been studied carefully

Popular controversial and alternative treatments

Sensory-Motor Therapies

– Auditory Integration Therapy, Sensory Integration Therapy, Facilitated Communication, Vision Therapy, Rapid Prompting Method

Complementary and Alternative Medicine (CAM)

– Diets, vitamin therapy, nonvaccination, secretin, chelation

Sensori-Motor Therapies

Theory: Sensory processing or motor planning problems underlie other problems in ASD

Facilitated Communication refuted (Mostert, 2001, JADD)

All others under-studied – “There exists so few studies that

conclusions [about sensory integration’s effectiveness] cannot be drawn.”

Dawson & Watling (2000)

CAM

Secretin and nonvaccination refuted (Demichelli et al., 2005; Williams et al., 2005, Cochrane Reports)

Chelation implausible and risky (Kane, 2006,

Pittsburgh Post-Gazette)

Other CAM interventions under-researched

– Available evidence not encouraging (e.g., Elder et al., 2006, JADD, on gluten-free, casein-free diet)

– Additional research underway

Hyperbaric Oxygen Therapy

Intended to reduce oxidative stress

Involves presenting pure oxygen at high atmospheric pressure

University of Houston-Clearlake & Downtown

The Rap on Applied Behavior Analysis

Most extensive and careful research on

interventions for individuals with autism

BUT evidence and benefits often

exaggerated, according to critics

(e.g., Herbert et al., SRMHP, 2002)

University of Houston

Initial Efficacy Studies

Demonstrate that intervention may produce change

Provide opportunities to hone treatment techniques

Feasible in a variety of settings

Sometimes may suffice to demonstrate potential utility of intervention •e.g., intervention is a straightforward, stand-alone procedure such as an approach for teaching self-help skills

Examples of skills-focused interventions with initial efficacy data

Discrete trial training (Smith, 2001, Focus)

•highly structured procedure with short and clear teacher

instructions, methods for prompting correct responses and

fading responses, and giving immediate reinforcement

Script fading (Bellini et al., 2007, JADD)

•presenting a script for a social interaction or other skill and then

removing the script

Incidental teaching (Delprato et al., 2001, JADD)

•instruction embedded in naturally-occurring activities

Skills-Focused Interventions (cont.)

•Functional Communication Training (Horner et al., 2002,

JADD): • teaching communication skills to replace challenging behavior

•Differential reinforcement for appropriate vs.

inappropriate behavior (Horner et al., 2002)

•Peer-mediated social skills training (Schwartz & Strain, 2001, Focus) • coaching peers to models or tutor social skills

•Discrimination training procedures (Green, 2001, Focus; Walker, 2008, JADD)

•Parent involvement (Odom et al., 2003, Focus)

Example of Comprehensive Intervention: Early Intensive ABA Much interest focused on early intensive

behavioral intervention (EIBI)

-20-40 hours of individual instruction

-Beginning at age 4 years or younger and

lasting 2-3 years

EIBI Many EIBI models, but UCLA/Lovaas

approach most extensively studied

Children with Pervasive Developmental Disorder Smith, Groen, & Wynn (2000, AJMR)

Participants: N = 28, 14 with autism, 14 with

PDDNOS

Chronological age < 42 months

Ratio IQ between 35 and 75

Absence of other major medical problems (e.g.,

cerebral palsy)

Groups: Stratified random assignment Intensive Treatment (n = 15):

Intended: 30 hrs/wk of one-to-one-treatment for

2-3 years

Actual: M = 24.52 hrs/wk for 33.44 months

Parent Training (n = 13):

5 hrs/wk of individualized, in-home training for 3

months

Measures Intake/Follow-up

Assessments

Bayley/Stanford-

Binet

Merrill-Palmer

Reynell

Vineland

Intake Only

Family Background

Follow-up Only

Parent Satisfaction

Wechsler Individualized

Achievement Test

Child Behavior Checklist

Teacher Report Form

Smith et al. (2000)

2-3

7-8

0

20

40

60

80

100

EIBI

Parent Tx

Age (Years)

IQ

Results of Smith et al. (2000)

At follow-up, EIBI group outperformed comparison group in several important areas: +16 IQ points +27 points on test of academic achievement +15 months in visual-spatial skills 4 of 15 fully included in general education (compared to 0 of 13 in comparison group)

Additional Results

Trend toward higher language scores in

EIBI group

High parent satisfaction in both groups

But no significant difference between

groups in adaptive behavior (Vineland) or

problem behavior

Subsequent EIBI Research Many more EIBI studies, especially after 2005

UCLA Model

Eikeseth, Smith et al. (2002, 2007, BMod)

Sallows & Graupner (2005, AJMR)

Eldevik, Smith et al. (2006, JADD)

Cohen, Amerine-Dickens & Smith (2006, JDBP)

Hayward et al. (2009)

Other EIBI Programs

Howard et al. (2005, RIDD)

Reed et al. (2007, JADD)

Remington et al. (2007, AJMR)

Zachor et al. (2007, RASD)

Magiati et al. (2007, AJMR)

Perry et al. (2008, RASD)

EIBI Studies 2 randomized clinical trials (both on the UCLA model)

10 quasi-experimental studies (3 on UCLA Model) -Studies with EIBI group and non-EIBI group

-Children assigned to groups based on parent preference or availability of EIBI rather than at random

10 studies with only an EIBI group -No control for progress that might have occurred without treatment

Does EIBI work? Most reviewers say “yes”

Spreckley & Boyd (2009) disagree, citing

insufficient evidence

Most reviewers note serious

methodological limitations such as:

-Unclear amounts of treatment -Limited range of outcome measures -Small sample sizes

If EIBI does work, how big are the effects?

Estimates from meta-analysis (statistical synthesis of research findings):

Reichow & Wolery (2009) Mean effect size for IQ = 0.69 -Average child in EIBI has more favorable outcome than 75% of children not in EIBI

-Considered fairly large effect

Eldevik et al. (2009)

Average effect size of 1.10 for IQ

Average child in EIBI has higher IQ than 86%

of comparison children

Average effect size of 0.66 for adaptive behavior

-Average child in EIBI has more advanced

adaptive behavior than 75% of comparison

children

Effect size (cont.)

Effect size (cont.)

Eldevik et al. (2010):

Individual children making reliable change:

-IQ: 27.1% in EIBI vs. 9.9% in comparison groups

-Adaptive behavior: 19.2% in EIBI, 7.0% in comparison groups

Number Needed to Treat: 4.5 for IQ, 7.0 for adaptive behavior

Possible Active Ingredients (Kasari, 2002, JADD)

Amount of treatment

•How many hours per week for how long?

Intervention method

•Most studies on discrete trial training, but would

other, more child-led ABA approaches be better?

Content

•What skills should be taught?

Amount of treatment

Some writers conclude that the most intensive

programs (30+ hours) may be most effective (Eldevik

et al., 2009; Reichow & Wolery, 2009)

•However, others say this conclusion is premature

(Rogers & Vismara, 2008)

Most changes may occur in the first year (Howlin et

al., 2009)

Method and Content

No studies currently available

Individual differences

All studies report wide individual

differences in outcome

IQ of Individual EIBIChildren in Lovaas (1987)

0

50

100

150

2-3 7

13

Age (Years)

IQ

Sallows & Graupner, (2005)

Predictors of Response Still not entirely clear

Some evidence that children who are higher-

functioning initially may benefit more

Age not associated with outcome among

preschoolers

Predicting outcome of EIBI

(Smith, Klorman, & Mruzek, 2009, in progress)

Case series of 71 children with autism in EIBI

•M(SD) age = 3.24 years (0.69)

Predicting outcome of EIBI (cont.)

Predictors:

Age

IQ

Social communication (measured by observation and parent

report)

-Imitation

-Joint attention

-Requesting

Independently of IQ, social communication predicts 1 year

outcome

Conclusions Most evidence indicates that EIBI works -UCLA/Lovaas Model is the most extensively tested EIBI approach

EIBI may be most effective for higher functioning children and when given intensively

Little information on other active ingredients

Still need well-designed clinical trials with large samples and an array of predictors and outcome measures

For more information, please go to the main website and browse for workshops on this topic or check out our additional resources. Additional Resources Online resources: 1. Association for Science in Autism Treatment: www.asatonline.org 2. National Institute of Mental Health: http://www.nimh.nih.gov/health/publications/autism/complete-index.shtml 3. Society of Clinical Child and Adolescent Psychology website: http://effective childtherapy.com

Books: 1. Smith, T. (2011). Applied behavior analysis and early intensive intervention. In D. G. Amaral, G. Dawson, & D. H. Geschwind (Eds.), Autism Spectrum Disorders (pp. 1037-1055). New York: Oxford University Press.

Selected Peer-reviewed Journal Articles: 1. Eikeseth, S., Smith, T., Eldevik, S., & Jahr, E. (2007). Outcome for children with autism who began intensive behavioral treatment between age four and seven: A comparison controlled study. Behavior Modification, 31, 264-278. 2. Eldevik, S., Hastings, R. P., Hughes, J. C., Jahr, E., Eikeseth, S., & Cross, S. (2009). Meta-analysis of early intensive behavioral intervention for children with autism. Journal of Clinical Child and Adolescent Psychology, 38, 439-450. 3. Lord, C., Wagner, A., Rogers, S., Szatmari, P., Aman, M., Charman, T., et al. [Smith, T., 20th author] (2005). Challenges in evaluating psychosocial interventions for autistic spectrum disorders. Journal of Autism and Developmental Disorders, 35, 696-708. 4. Remington, B., Hastings, R. P., Kovshoff, H., degli Espinosa, F., Jahr, W., Brown, T., et al. (2007). A field effectiveness study of early intensive behavioral intervention: Outcomes for children with autism and their parents after two years. American Journal on Mental Retardation, 112, 418–438. 5. Rogers, S. J., & Vismara, L. A. (2008). Evidence-based comprehensive treatments for early autism. Journal of Clinical Child and Adolescent Psychology, 37, 8-38. 6. Sallows, G., & Graupner, T. (2005). Intensive behavioral treatment for autism: Four-year outcome and predictors. American Journal on Mental Retardation, 110, 417-436. 7. Smith, T., Groen, A., & Wynn, J. W. (2000b). Randomized trial of intensive early intervention for children with pervasive developmental disorder. American Journal on Mental Retardation, 104, 269-285.

Full References Keynote: Evidence-Based Practices for Children with Autism Spectrum Disorders Websites: 1. Association for Science in Autism Treatment: www.asatonline.org 2. National Institute of Mental Health: http://www.nimh.nih.gov/health/publications/autism/complete-index.shtml Book Chapters: Smith, T. (2011). Applied behavior analysis and early intensive intervention. In D. G. Amaral, G.

Dawson, & D. H. Geschwind (Eds.), Autism Spectrum Disorders (pp. 1037-1055). New York: Oxford University Press.

Early Intensive Behavioral Intervention Studies Anderson, S. R., Avery, D. L., DiPietro, E. K., Edwards, G. L., & Christian, W. P. (1987). Intensive

home-based early intervention with autistic children. Education and Treatment of Children, 10, 352-366.

Bibby, P., Eikeseth, S., Martin, N. T., Mudford, O. C., & Reeves, D. (2002). Progress and outcomes for children with autism receiving parent-managed intensive interventions. Research in Developmental Disabilities, 23, 81-104.

Birnbrauer, J. S., & Leach, D. J. (1993). The Murdoch early intervention program after 2 years. Behavior Change, 10, 63-74.

Cohen, H. Amerine-Dickens, M., & Smith, T. (2006). Early intensive behavioral treatment: Replication of the UCLA Model in a community setting. Journal of Developmental and Behavioral Pediatrics, 27, S145-S155.

Eikeseth, S., Smith, T., Eldevik, S., & Jahr, E. (2007). Outcome for children with autism who began intensive behavioral treatment between age four and seven: A comparison controlled study. Behavior Modification, 31, 264-278.

Harris, S. L., & Handleman, J. S. (2000). Age and IQ at intake as predictors of placement for young children with autism: A four- to six-year follow-up study. Journal of Autism and Developmental Disorders, 30, 137-142.

Harris, S. L., Handleman, J., Gordon, R., Kristoff, B., & Fuentes, F. (1991). Changes in cognitive and language functioning of preschool children with autism. Journal of Autism and Developmental Disabilities, 21, 281-290.

Harris, S., Handleman, J. S., Kristoff, B., Bass, L., & Gordon, R. (1990). Changes in language developmental among autistic and peer children in segregated and integrated preschool settings. Journal of Autism and Developmental Disorders, 20, 23-31.

Hayward, D. W., Gale, C. M., & Eikeseth, S. (2009). Intensive behavioural intervention for young children with autism: A research-based service model. Research in Autism Spectrum Disorders, 3, 571-580.

Howard, J. S., Sparkman, C. R., Cohen, H. G., Green, G., & Stanislaw, H. (2005). A comparison of intensive behavior analytic and eclectic treatments for young children with autism. Research in Developmental Disabilities, 26, 359-383.

Magiati, I., Charman, T., & Howlin, P. (2007). A two-year prospective follow-up study of community-based early intensive behavioural intervention and specialist nursery provision for children with autism spectrum disorders. Journal of Child Psychology and Psychiatry, 48, 803–812.

Perry, A., Cummings, A., Dunn Geier, J., Freeman, N. L., Hughes, S., LaRose, L., et al. (2008). Effectiveness of Intensive Behavioral Intervention in a large, community-based program.

Full References

Research on Autism Spectrum Disorders, 2, 621-642. Reed, P., Osborne, L. A., & Corness (2007a). The real-world effectiveness of early teaching

interventions for children with autism spectrum disorder. Exceptional Children, 73, 417–433.

Reed, P., Osborne, L. A., & Corness (2007b). Brief report: Relative effectiveness of different home-based behavioral approaches to early teaching intervention. Journal of Autism and Developmental Disorders, 37, 1815–1821.

Remington, B., Hastings, R. P., Kovshoff, H., degli Espinosa, F., Jahr, W., Brown, T., et al. (2007). A field effectiveness study of early intensive behavioral intervention: Outcomes for children with autism and their parents after two years. American Journal on Mental Retardation, 112, 418–438.

Sallows, G., & Graupner, T. (2005). Intensive behavioral treatment for autism: Four-year outcome and predictors. American Journal on Mental Retardation, 110, 417-436.

Sheinkopf, S. J., & Siegel, B. (1998). Home-based behavioral treatment of young children with autism. Journal of Autism and Developmental Disorders, 28, 15-23.

Smith, T., Buch, G.A., & Evslin, T. (2000a). Parent-directed, intensive early intervention for children with pervasive developmental disorder. Research in Developmental Disabilities, 21, 297-309.

Smith, T., Eikeseth, S., Klevstrand, M., & Lovaas, O.I. (1997). Outcome of early intervention for children with pervasive developmental disorder and severe mental retardation. American Journal on Mental Retardation, 102, 228-237.

Smith, T., Groen, A., & Wynn, J. W. (2000b). Randomized trial of intensive early intervention for children with pervasive developmental disorder. American Journal on Mental Retardation, 104, 269-285.

Weiss, M. J. (1999). Differential rates of skill acquisition and outcomes of early intensive behavioral intervention for autism. Behavioral Interventions, 14, 3-22.

Zachor, D. A., Ben-Itzhak, E., Rabinovitz, A-L., & Lahat, E. (2007). Change in core symptoms with intervention. Research in Autism Spectrum Disorders, 1, 304-317.

Reviews Bellini, S., & Akullian, J. (2007). A meta-analysis of video modeling and video self-modeling

interventions for children and adolescents with autism spectrum disorders. Exceptional Children, 73, 264-287.

Delprato, D. J. (2001). Comparisons of discrete-trial and normalized behavioral intervention for young children with autism. Journal of Autism and Developmental Disorders, 31, 315-325.

Eikeseth, S. (2008). Outcome of comprehensive psych-educational interventions for young children with autism. Research in Autism Spectrum Disorders, 2.

Eldevik, S., Hastings, R. P., Hughes, J. C., Jahr, E., Eikeseth, S., & Cross, S. (2009). Meta-analysis of early intensive behavioral intervention for children with autism. Journal of Clinical Child and Adolescent Psychology, 38, 439-450.

Eldevik, S., Hastings, R. P., Hughes, J. C., Jahr, E., Eikeseth, S., & Cross, S. (2010). Using participant date to extend the evidence base for intensive behavioral intervention for children with autism. American Journal of Intellectual and Developmental Disabilities, 115, 381-405.

Goldstein, H. (2002). Communication interventions for children with autism: A review of treatment efficacy. Journal of Autism and Developmental Disorders, 32, 373-396.

Green, G. (2001). Behavior analytic instruction for learners with autism: Advances in stimulus control technology. Focus on Autism & Other Developmental Disabilities, 16, 72-85.

Full References Horner, R. H., Carr, E. G., Strain, P. S., Todd, A. W., & Reed, H. K. (2002). Problem behavior

interventions for young children with autism: A research synthesis. Journal of Autism and Developmental Disorders, 32, 423-446.

Howlin, P., Magiati, I., & Charman, T. (2009). Systematic review of early intensive behavioral interventions for children with autism. American Journal on Intellectual Disabilities, 114, 23-41.

Lord, C., Wagner, A., Rogers, S., Szatmari, P., Aman, M., Charman, T., et al. [Smith, T., 20th author] (2005). Challenges in evaluating psychosocial interventions for autistic spectrum disorders. Journal of Autism and Developmental Disorders, 35, 696-708.

Odom, S. L., Boyd, B. A., & Hall, L. J. (2010). Evaluation of comprehensive treatment models for children with autism. Journal of Autism and Developmental Disorders, 40, 425-436.

Odom, S. L., Brown, W. H., Frey, T., Karasu, N., Smith-Canter, L. L., & Strain, P. S. (2003). Evidence-based practices for young children with autism: Contributions from single-subject design research. Focus on Autism and Other Developmental Disabilities, 18, 166-175.

Reichow, B., & Wolery, M. (2009). Comprehensive synthesis of early intervention behavioral interventions for young children with autism based on the UCLA Young Autism Project model. Journal of Autism and DevelopmentalDisorders, 39, 23-41.

Rogers, S. J., & Vismara, L. A. (2008). Evidence-based comprehensive treatments for early autism. Journal of Clinical Child and Adolescent Psychology, 37, 8-38.

Smith, T., Scahill, L., Dawson, G., Guthrie, D., Lord, C., Odom, S., Rogers, S., et al. (2007). Designing research studies on psychosocial interventions in autism. Journal of Autism and Developmental Disorders, 37 (2), 354-366.

Spreckley, M., & Boyd, R. (2009). Efficacy of applied behavioral intervention in preschool children with autism for improving cognitive, language, and adaptive behavior: A systematic review and meta-analysis. Journal of Pediatrics, 154, 338-344.

Strain, P. S., & Schwartz, I. (2001). ABA and the development of meaningful social relations for young children with autism. Focus on Autism and Other Developmental Disabilities, 16, 120-128.

Walker, G. (2008). Constant and progressive time delay procedures for teaching children with autism: A literature review. Journal of Autism and Developmental Disorders, 38, 261-375.

Retrieved from http://www.EffectiveChildTherapy.fiu.edu