Overview of autism spectrum disorder (ASD)

Autism Spectrum Disorder (ASD) is a ‘neurodevelopmental disorder’. This is a category of brain disorder where problems originating in the brain interfere with a child's typical development, resulting in a range of symptoms and difficulties. ASD encompasses a range of neurodevelopmental disorders which were formerly diagnosed separately as Asperger's Syndrome (AS), Pervasive Developmental Disorder (PDD), and autism. However, due to significant overlap between them, they are now collectively identified as ASD.¹

The term spectrum in ASD encapsulates the diversity and interconnectedness of symptoms in ASD, characterised by three key issues:

• Difficulties in social interaction and communication
• Sensory differences
• Persistent engagement in restricted or repetitive behaviours and interests

While these symptoms typically manifest in the first few years of life, the diverse nature of ASD makes diagnosis and treatment notoriously challenging. Common additional challenges for individuals with ASD include delayed or absent language development, difficulty in using and understanding non-verbal communication, gastrointestinal issues, eating difficulties, sleep problems, learning difficulties, epilepsy, ADHD, and various psychiatric disorders (e.g., depression, OCD, and anxiety). 

It's important to note that there is currently no cure for ASD but some medications can be used to address symptoms associated with it, like anxiety, irritability, and depression. Many different behavioural techniques are also used for treating symptoms and improving quality of life, such as the Applied Behaviour Analysis (ABA), which is the most common.

It’s also important to note that due to the wide range of possible symptoms, there is no single best treatment for ASD. So, working with a healthcare provider to find the treatment combination that suits the particular individual is essential.² 

Overview of applied behaviour analysis (ABA)

At its core, ABA is about using our understanding of conditioning and learning theory to understand or change certain deficits and problematic behaviours commonly found in people with ASD. The deficits targeted can be related to cognition, language, problem behaviour or daily living skills.

However, there appears to be some confusion about ABA's definition amongst the scientific community as it is inconsistently defined. Some agencies, such as the CDC, define ABA as a treatment approach itself, whereas others, such as the NIH, describe ABA as a set of principles that have inspired various loosely connected treatment models.^2,8

To complicate the picture, there is a lot of variation in how ABA is practised. Some ABA programs follow a strict protocol, while others consist of a collection of specific techniques associated with ABA which are adapted to the individual.²

Comprehensive ABA treatment models aim to address functioning at all levels, including cognition, language, social skills, problem behaviour, and daily living skills.^2,3 The main objectives of the majority of these treatment models are to: 

• Increase language and communication skills
• Improve cognitive skills such as attention, focus, memory, and academic performance
• Improve social skills and decrease problem behaviours

ABA-based treatment techniques

A variety of more focused techniques are used within the comprehensive treatment models, or in addition to them. These may include: 

• Discrete trial training (DTT)
• Pivotal response treatment (PRT)
• Functional communication (FCT)
• Positive reinforcement
• Extinction
• Prompting
• Video modelling
• Picture exchange communication system (PECS)

Below is an overview of 3 of the more commonly used focused techniques.

Discrete trial training (DTT)

DTT is one of the oldest techniques used in ABA, aiming to replace problem behaviours with target behaviours. It is a highly structured and controlled technique, where skills are broken down into small (discrete) components and ‘trialled’ frequently, in distraction-free, one-to-one settings.⁴

Discrete trial training is built off of the ‘ABCs of ABA’:

• Antecedents – events, actions or circumstances that occur before a behaviour and may trigger it
• Behaviours – something the individual does
• Consequences – the actions/responses/events that follow the behaviour

Usually, an external observer is asked to watch the person with ASD as they are trialled during specific times of the day. The observer records the antecedents, behaviours and consequences, as they occur. Technically anyone (e.g., parents, educators, teachers, support personnel, administrators) can record the data when given clear direction and parameters from an ABA professional.^1,3

An example is shown below: 

After this data has been collected, it is analysed to determine the reasons behind problem behaviours, what sustains these behaviours, and how to replace them with more appropriate and healthy behaviours. 

Target behaviours are considered the correct response and these are rewarded. Some therapists may also guide the behaviour to encourage the ‘correct response.’ The idea is that, over time, the therapist will give less and less assistance and the person with ASD will perform the target behaviour independently.^1,3

Pivotal response treatment (PRT)

Another technique based on the antecedents, behaviour and consequences model of ABA is PRT or Pivotal Response Treatment.⁵ It also involves trials of behaviour which are recorded and analysed. However, there are 3 main differences between DDT and PRT. In PRT:

• The skills targeted are considered ‘pivotal’ to development, whereby acquiring them leads to gains in multiple areas of life such as motivation, self-initiation, self-management and communication
• Any behaviours that are deemed valid attempts of the desired behaviour are rewarded
• It focuses on involving peers, siblings and family members to enhance generalisation to the real world

Picture exchange communication system (PECS)

The picture exchange communication system provides the ASD individual with an alternative way of communicating – using pictures instead of words. Similarly to other ABA techniques, the consequences of certain behaviours are taught to the ASD individual but, in this case, the ASD individual is taught that indicating a picture (usually pointing or holding) results in a consequence. 

In the beginning stages of using the PECS system, ASD individuals are often taught to ask for something, such as their favourite food or drink, using this system. This usually involves pointing to the card to get the food/drink they want. In later stages, the individual may be able to learn how to use the cards to build sentences. 

Similarly to DDT and PRT, this picture-consequence association is also trialled frequently so that the ASD individual learns the association well and starts to use it independently.

ABA-based comprehensive models

As mentioned above, different comprehensive models may be used in the treatment of ABA and they differ slightly in their aims and techniques involved.^2,7 There are many models, but below are 3 of the more commonly used ones:

Early intensive behavioural intervention (EIBI)

Early Intensive Behavioural Intervention (EIBI) is an ABA-based treatment targeted at children under the age of 5. It usually consists of individualised instruction for children with ASD for around 20-40 hours per week, continuing for a number of years. It is usually conducted 1-1 in a structured setting such as a school. The focused techniques within this model usually include DDT complemented by other less structured techniques.⁶

Early start denver model (ESDM)

Also aimed at children under 5 years old, the Early Start Denver Model (ESDM) is rooted in the more naturalistic teaching methods of ABA. It focuses on using play to cultivate the relationship between the person with ASD and their peers and family. 

A team made of therapists, parents and other trained staff work together to develop a tailored program, including objectives, goals and activities aiming at enhancing social-emotional, cognitive, and language development. ESDM thus fuses a developmental, play-based, relationship-based approach with principles of applied behaviour analysis to create an integrated whole that is both individualised and manualised.³

Learning experiences: an alternative program for preschoolers and their parents (LEAP)

LEAP strongly emphasises parental and peer involvement and naturally occurring teaching arrangements, instead of structured, teacher-led instruction, to be more naturalistic and generalisable. It usually takes place in a public school instead of a special education school like in ESDM and EIBI. It includes methods commonly used in ABA, such as PRT, time delay and incidental teaching, peer-mediated interventions and the PECS.

ABA – criticisms and controversies 

ABA has been shrouded in controversy due to several issues, including unclear definitions of what constitutes ABA, differences in how ABA is practised, inconsistent evidence in the literature regarding ABA’s effectiveness, and complaints from individuals with ASD and their parents.^9,10

Scientific evidence supporting the efficacy of ABA

Despite the confusion in its definition and variability in how it is practised, ABA techniques have been researched extensively and a large amount of evidence supports its use, leading to ABA being considered evidence-based best practice.⁸ It is endorsed by a number of scientific, professional, and government agencies worldwide, including the American Association on Intellectual and Developmental Disabilities (AAIDD) and the Surgeon General of the United States.

However, there are some inconsistencies in the literature, with some large studies finding some ABA protocols as not effective at improving language skills, communication, ability to learn, daily living skills and appropriate social behaviour. However, this inconsistency may be due to grouping many ABA techniques despite how differently they are practised. 

Experience of ABA as an ASD individual 

Some adults with ASD, reflecting on their ABA training, argue that ABA damaged their mental health by making them feel like they were a ‘problem to be fixed’. They also argue that they shouldn’t be made to behave like their peers anyway. Furthermore, while some of these individuals say that ABA helped them in some ways, they add that they suffered a lot of negative consequences and, on balance, it is an unethical practice that should be replaced with something else.

However, there are also many success stories which can be found online. It is important to note that ABA has changed over the last 60 years and that the methods that fall under ABA vary significantly. These two facts may explain the mixed reviews.

Summary 

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterised by communication issues, sensory differences, and repetitive behaviours. There is no cure for it but medications can be used for some symptoms and behavioural techniques, notably Applied Behaviour Analysis (ABA), which can be used to target deficits and problem behaviours. ABA is based on conditioning and learning theory and is associated with a range of techniques including DDT, PRT, and the PECS.

Comprehensive ABA models target cognition, language and social skills and differ slightly in terms of the techniques used and what they focus on. 

Controversies surround ABA due to unclear definitions of ABA, practice variations, inconsistent evidence when examining many ABA treatments together, and reports from some ASD individuals and their parents. Some claim there is a negative impact on mental health, while others share success stories. Despite criticisms, scientific support for ABA's efficacy is quite strong, leading to endorsements by a variety of government, professional and scientific institutions worldwide. Concerns about ABA may persist as it continues to evolve over the years.