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Discrete Trial Training and Autism Ranking: Limited positive evidence

Carer teaching a child with autism

Discrete trial training (DTT) is a highly-structured training technique that involves a trainer instructing an individual on the autism spectrum using a series of learning opportunities or ‘trials’. Each ‘trial’ has a definite beginning and end, which is why they are described as ‘discrete’.

The trainer begins each trial with a short, clear instruction or a question. The trainer may also prompt the learner, showing him how to respond correctly to the instruction or question.

If the learner does what the trainer wants, she will immediately reward him. For example, she may praise him or allow him to have something he wants or likes. If the learner does not do what the trainer wants, she will repeat the instruction or try a slightly different approach.

DTT is the main (but not the only) strategy used to teach children on the autism spectrum in early intensive behavioural interventions based on applied behaviour analysis, such as the UCLA YAP Model.

Our Opinion

DTT can be a useful procedure for very specific targeted behaviours or skills as part of a broader programme of intervention.  However, if it is seen as an end in its own right, it is unlikely to produce lasting benefits (for example, by not actively teaching skills that can be used in situations or settings outside of the training session).

Future research should use randomised controlled designs to investigate the effectiveness of DTT against active control groups (for example, by directly comparing DTT with other interventions, relative to a no-treatment control group) using larger sample sizes.

It would also be helpful to identify the effectiveness of DTT, where DTT is a part of a wider programme, investigating whether and how DTT adds value to the programme (for example, are there particular skills that are more receptive to being taught using DTT techniques than others).

It would be helpful to examine the efficacy and any side effects of DTT on the autistic participants, such as stress or self-injurious behaviour, and over a much longer period.

Any future research should also involve people on the autism spectrum to review the efficacy and ethical basis of discrete trial training including individuals who may be non-verbal.

Disclaimer

Please read our Disclaimer on Autism Interventions

Audience

According to Simpson (2005) DTT is suitable for anyone on the autism spectrum.

In practice, it is most commonly used with children with more significant autism.

Aims and Claims

Aims

According to Reynolds and Dombeck (2006), the main aim of discrete trial training is to teach the learner how to pay attention and how to communicate.

"Therapists are ultimately interested in getting children to pay attention to task learning and in developing their ability to respond appropriately to communication. Letters, numbers and object labeling skills are thus acquired as a byproduct of discrete trials training. Because communicative skills are basic and fundamental and must be present before more complex social skills can be taught, they are taught early on in the process."

Once these basic skills have been taught, the learner is ready to acquire other skills, such as dressing, eating, making a bed etc. However, acquiring communication is often considerably more complicated than this and is often the main lifelong learning need for children with significant autism

Claims

 There have been various claims made for discrete trial training. For example

  • Grindle and Remington,  2002; Jones Feeley and Takacs, 2007; and Miranda-Linné and Melin, 1992  reported improvements in communication skills
  • Jones, Carr, and Feeley, 2006 reported improvements in joint attention, alongside improvements in expressive language and social-communication
  • Newman et al. 2002 reported improvements in skill acquisition
  • Taubman et al, 2001 reported improvements in the acquisition of educational skills
  • Sigafoos and Saggers, 1995 reported that the discrete-trial approach presented a useful technique for the functional analysis of challenging behavior

According to a review by Smith (2001)

"'For children with autism, DTT is especially useful for teaching new forms of behavior (e.g., speech sounds or motor movements that the child previously could not make) and new discriminations (e.g., responding correctly to different requests). DTT can also be used to teach more advanced skills and manage disruptive behavior."

In practice, DTT often produces changes in very specific skills, such as naming things like objects or colours, rather than changes in broader skills, such as communication as a whole.

Key Features

Discrete trial training (DTT) is a highly-structured training technique that involves a trainer instructing an individual on the autism spectrum using a series of learning opportunities or ‘trials’. Each ‘trial’ has a definite beginning and end, which is why the trials are described as ‘discrete’.

The trainer begins each trial with a short, clear instruction or a question. The trainer may also prompt the learner, showing him how to respond correctly to the instruction or question.  For example, the teacher may hold up a picture of a ball and say ‘What is this? Ball’. She may then repeat the question with or without the answer in order to encourage the learner to say ‘Ball’.

If the learner does what the trainer wants, she will immediately reward him. For example, she may praise him or allow him to have something he wants, such as the ball. If the learner does not do what the trainer wants, she will repeat the instruction or try a slightly different approach.  In order to be effective the rewards must be tangible and be given to the learner immediately. Otherwise the learner may not associate them with the behaviours being taught.

Discrete trial training allows the trainer to break complex tasks down into smaller, simpler steps, each of which can be repeated until it is mastered. Complicated skills can be built, or ‘scaffolded’, on simpler ones. For example, the trainer may teach the learner how to say "hello, how are you" before teaching him more complex social communication tasks such as greeting someone (which may also involve making eye contact, and paying attention to what the other person has to say).

Cost and Time

Cost

The costs of using DTT will depend to a large extent on who provides the training, how long it takes to implement the intervention, and whether support materials are purchased.

Time

Like many other interventions, the length and frequency of treatment will depend to a large extent on the needs of the individual.  For example, if DTT is delivered as part of a larger early intensive behavioural programme it may require many hours of work each day and be implemented over many years.

According to ICAN

"The total time for a DTI teaching sequence would be from 15 to 20 minutes in length. The student then would have a short break (5 to 15 minutes) between individual programs/lessons."

Within each DTI teaching sequence, each trial usually lasts between 5 and 30 seconds, with the teacher providing a break between trials.

Risks and Safety

Hazards

There are few known hazards for discrete trial training. However, it has been heavily criticised by some people on the autism spectrum. For example, the website autism.wikia.com (Open in New Window), accessed on 29 February 2016, contains a detailed list of criticisms of ABA and DTT in particular from people on the autism spectrum.

Contraindications

There are no known contraindications for this intervention. However Smith (2001) reported

"..  several cautions about DTT are noteworthy: First, the method must be combined with other interventions to enable children to initiate the use of their skills and display these skills across settings. Second, early in treatment, children with autism may require many hours of DTT per week, although controversy exists over precisely how much is appropriate. Third, to implement DTT effectively, teachers must have specialized training. Despite these limitations, DTT is one of the most important instructional methods for children with autism."

Schreibman et al (2015) reported

".. research showed that highly structured interventions such as DTT, while effective in teaching skills, sometimes led to (1) child failure to generalize newly learned skills across multiple environments and circumstances, (2) the presence of escape /avoidance challenging behaviors, (3) lack of spontaneity and (4) overdependence on prompts."

Suppliers and Availability

Suppliers

In theory, DTT is only available from a small number of (usually commercial) agencies, such as the Lovaas Institute in the US and Child Autism UK, and as part of a broader ABA programme. In practice, DTT may actually be implemented by a variety of people, including parents and carers, as well as professionals such as teachers.

Support materials are also available from a range of organisations.

Credentials

According to Simpson et al. (2005)

"Individuals implementing DTT need specialized training that includes theoretical and supervised practical experience in one-to-one behavioral treatment. Smith distinguishes between two levels of proficiency for providing DTT. At the first level, educators can implement DTT with supervision but they cannot develop DTT curricula for specific children. At the second level, educators can supervise DTT programs and be responsible for developing DTT curricula, as well as instruct new teachers to implement this strategy."

There is no internationally recognised qualification for the delivery of DTT but organisations such as the Lovaas Institute in the US and Child Autism UK in the UK run various training programmes for parents and professionals.

In the UK some universities offer degrees in behaviour analysis, including the use of DTT. A stronger indication, but not a guarantee of professional expertise, is the letters BCBA (Board Certified Behaviour Analyst) or BCABA (Board Certified Associate Behaviour Analyst), which is similar but requires less experience. These qualifications indicate that the person has completed coursework in behaviour analysis, had clinical training and passed an exam administered by the Behaviour Analyst Certification Board.

In the USA, ABA programs for learners on the autism spectrum should be designed and supervised by qualified behavior analysts, preferably individuals who are Board Certified Behavior Analysts with supervised experience providing ABA treatment for autism, or who can clearly document that they have equivalent training and experience.

History

DTT was developed by Dr. O. Ivar Lovaas as a key part of the Lovaas Method in the early 1970s in the USA. Dr. O. Ivar Lovaas worked with non-verbal, institutionalised children on the autism spectrum in the late 1960s and early 1970s in the USA. He concentrated on improving verbal skills using applied behavioural analysis.

Unfortunately most of the children lost their verbal skills when the programme ceased and they returned to institutional life. However those who moved back with their parents did much better.

Lovaas went on to work with younger children, aged 2 to 4, in their home setting to see if the skills learned by the children were maintained. He developed Early Intensive Behavioural Intervention (The Lovaas Method) from this work.

Current Research

We have identified more than 50 scientific studies of discrete trial training used as a stand-alone technique for people on the autism spectrum published in peer-reviewed journals. These studies do not include occasions when discrete trial training is used within other, larger programmes such as within early intensive behavioural interventions.

These studies included more than 350 individuals on the autism spectrum aged from 2 years old to adult.

  • The majority of studies (for example, Devlin and Harber, 2004; Elliott, Hall, Soper, 1991; Grindle and Remington, 2002; Jones, Carr, Feeley. 2006; Jones Feeley, Takacs, 2007; Miranda-Linné and Melin, 1992; Newman et al. 2002; Sigafoos and Saggers, 1995; Sigafoos et al, 2006; Taubman et al, 2001) reported one or more positive benefits from discrete trial training.
  • Some studies (for example Holding et al,  2011; Koegel et al, 1992; Koegel et al, 1998;  Schreibman, Kaneko, Koegel, 1991; Schreibman  et al., 2009; and Sigafoos et al, 2006) reported limited or mixed results, in some cases suggesting that other interventions such as incidental teaching or pivotal response training provided more benefits than discrete trial training.
  • One study (Sigafoos et al, 2006) reported that DTT led to increased self injury in the single participant.

Status Research

There are a number of limitations to all of the research studies on DTT published to date.  For example

  • the majority of the studies had 10 or less participants, with most having 3 or less participants
  • the majority of the studies used low quality methods such as multiple baseline or alternating design
  • three of the five controlled studies had less than 20 participants and two of the three randomised controlled studies had less than 30 participants
  • some of the studies which reported that discrete trial training was less successful than other interventions (such as pivotal response training) were carried out by researchers who helped to develop those other interventions

For a comprehensive list of potential flaws in research studies, please see "Why some autism research studies are flawed."

Ongoing Research

  • University of California, Davis is running a multi-site randomized study of intensive treatment for toddlers with autism.  Clinical Trials Gov Ref: NCT02272192.  For more details, please see Intervention Effects of Intensity and Delivery Style for Toddlers With Autism (TADPOLE) Full Item (Open in New Window)
  • University of California, Los Angeles is running a multi-site randomised control study of early intervention for spoken communication in autism.  Clinical Trials Gov Ref:  NCT01018407. For more details, please see Interventions for Communication in Autism Network (ICAN). Full Item (Open in New Window)
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) is running a randomised controlled study of adaptive interventions for minimally verbal children with ASD in the community.   Clinical Trials Gov Ref: NCT01751698.  For more details, please see Adaptive Interventions for Minimally Verbal Children With ASD in the Community (AIM-ASD). Full Item (Open in New Window)

Future Research

Summary of Existing Research

There is strong evidence to show that DTT can be a useful procedure – but only as part of a broader programme of intervention. There is insufficient evidence to show that, used as an end in its own right, it will produce lasting benefits.

We have been unable to identify any personal anecdotes which are specifically about the use of DTT for people on the autism spectrum.  However we have identified numerous accounts of the use of ABA programmes which incorporate DTT.

Recommendations for Future Research

Future research should use randomised controlled designs to investigate the effectiveness of DTT against active control groups (for example, by directly comparing DTT with other interventions, relative to a no-treatment control group) using larger sample sizes.

It would also be helpful to identify the effectiveness of DTT, where DTT is a part of a wider programme, investigating whether and how DTT adds value to the programme (for example, are there particular skills that are more receptive to being taught using DTT techniques than others).

It would be helpful to examine the efficacy and any side effects of DTT on the autistic participants, such as stress or self-injurious behaviour, and over a much longer period.

Any future research should also involve people on the autism spectrum to review the efficacy and ethical basis of discrete trial training including individuals who may be non-verbal.

Studies and Trials

This section provides details of scientific studies into the effectiveness of this intervention for people with autism which have been published in English-language, peer-reviewed journals. If you know of any other studies we should include please email info@researchautism.net with the details. Thank you.

Please note that Research Autism is unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.

Other Reading

This section provides details of other publications on this topic. If you know of any other publications we should include please email info@researchautism.net with the details. Thank you.

Please note that Research Autism is unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.

Personal Accounts

This section provides details of personal accounts of the use of discrete trial training for people on the autism spectrum.

Personal accounts can be useful sources of information about the intervention but are not as scientifically valid or reliable as research trials. This may be especially true where the accounts are published by an organisation which might gain a financial advantage from the take-up of the intervention.

Please note that the views expressed in these personal accounts do not necessarily represent the views of Research Autism.


We have yet to identify any personal accounts which are specifically about the use of discrete trial training and individuals on the autism spectrum. However we have identified numerous accounts of the use of ABA programmes which incorporate DTT.

These include accounts from the following websites

If you know of any personal accounts which are specifically about the use of discrete trial training and individuals on the autism spectrum that you think we should include please email info@researchautism.net with the details. 

Updated
31 Oct 2017
Last Review
30 Mar 2016
Next Review
01 Mar 2019