Week 5-Diagnosing ASD

Week 5: Diagnosing Autism Spectrum Disorder

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Atypical Development

1. Understand criteria for ASC diagnosis and changes over time.
2. Consider what factors could be driving an increase in ASC diagnoses
3. Appreciate the complexities of childhood communication, emotional and behavioural problems in terms of co-morbidities
4. To consider the best possible diagnosis for ASC.

Learning Outcomes

Exam Focus

Diagnostic tools and process

Documentary: Unmasking my autism

Overview

Christine McGuiness Unmasking my autism

• Data from the School Census from the National Pupil Database, collected by the Department for Education from individuals aged 2-21 years old in state-funded schools in England
• More than 7 million pupils studies
• Around one in 57 (1.76%) children in the UK
• Boys showed a prevalence of autism of 2.8% and girls showed a prevalence of 0.65%, with a boy-to-girl ratio of 4.3:1.
• Black and Chinese pupils were 26% and 38% more likely to be autistic respectively and autistic children were much more likely to face significant social disadvantage.

Raising rates of ASD in the UK (Roman-Urrestarazu et al., 2021)

Possible reasons for the observed increase in rates of ASD

• Changes in diagnostic criteria
• Differences in methods used in the studies
• Increasing awareness among parents, professionals, and the general public of the existence of ASD
• Recognition that ASD conditions can be associated with other developmental or physical disorders, average or high intellectual ability, psychiatric disorders
• The development of specialist services
• Possible causes and relation to age of onset
• Possible true increase in numbers

Causes of rising rates?

Statement on Thiomersal: “The Global Advisory Committee on Vaccine Safety concludes that there is no evidence of toxicity in infants, children or adults exposed to thiomersal (containing ethyl mercury) in vaccines.”Thimerosal/thiomersal removed from vaccines in Australia in 2000.

Not vaccines – according to 100s studies and meta-analyses but are a couple dozen contrary studies re: thimerosal (Hg) and/or Aluminium adjuvantWHO 2006.

Exam Focus

Diagnostic tools and process

Is Diagnosis rising? How it is diagnosed?

Overview

1. Persistent deficits in social communication:

• Social-emotional reciprocity
• Non-verbal communication
• Understanding and maintaining relationships

2. Restricted, repetitive patterns of behaviour:

• Stereotyped movements
• Inflexible routines
• Fixated interests
• Hyper- and hypo- sensitivities

Symptoms present since early development Significant impairment Not solely due to intellectual disability

• Specify severity: 1 “requiring support”, 2 “substantial support”, 3 “very substantial support”

DSM-5 Criteria for ASD

2. Critically evaluate the usefulness of using only the ADOS for diagnosing autism spectrum disorders. What other tools and measures might be useful?

Exam Focus

ASD has a number of co-occuring physical and mental health conditions

• Epilepsy
• Sleep disorders/disturbance
• ADHD
• Gastrointestinal disorders
• Feeding/eating challenges
• Obesity
• Anxiety
• Depression
• Bipolar disorder

Frequent comorbidities with ASD

• Can last throughout life but may also appear and diminish at different developmental stages
• Diagnosis of comorbidities can be challenging because many people with ASD have difficulty recognizing and communicating their symptoms.
• As many as 85% of children with autism also have some form of comorbid psychiatric diagnosis, and 35% are taking at least 1 psychotropic medication as treatment
• Co-occurring diagnoses of Autism and ADHD have only been permissible since 2013 (DSM-5; American Psychiatric Association [APA], 2013)

Frequent comorbidities with ASD

• The research, which evaluated medical records of children referred for autism assessments, revealed that 76.2% of these children also exhibited traits associated with other neurotypes such as ADHD.
• Over half (55.6%) of the children assessed for autism potentially met the criteria for ADHD, indicating a high level of co-occurrence.
• Despite the clinical overlap, only 26% of children with additional traits were investigated for an underlying diagnosis, stressing the need for more comprehensive evaluation methods.

Overlapping neurotypes (Lang et al., 2024)

Before diagnosis parents of children with ASD might observe:

• not drawing their parents’ or others’ attention to objects or events, for example not pointing at a toy or a book, or at something that is happening nearby (or a child may eventually do this, but later than expected)
• carrying out activities in a repetitive way, for example always playing the same game in the same way, or repeatedly lining toys up in a particular order
• resistance to change or doing things differently
• emerging difficulties with social interaction and social communication
• behaviour such as biting, pinching, kicking, pica (putting inedible items in the mouth), or self-injurious behaviour.

Pre-diagnosis

• GP or health visitor-useful to keep a behaviour diary
• Screening-M-CHAT (Modified Checklist for Autism in toddlers) for pre-school children
• SENCO (Special Educational Needs Coordinator) or Learning Support Teacher
• GP-referral for a formal assessment (diagnosis)-waiting lists
• A multi-disciplinary diagnostic assessment-an assessment by a team of professionals
• Private assessment waiting times, costly, may not be accepted by some local authorities

Getting a referral

There are a number of tools which are used to diagnose individuals who might be autistic: Indirect:

• ADI-R (Autism Diagnostic Interview-Revised)
• DISCO (Diagnostic Interview for Social and Communication Disorders)

Direct:

• ADOS (Autism Diagnostic Observation Schedule)

• CARS-Childhood Autism Rating Scale

Diagnostic Tools

Indirect Assessment

• Interviews and Questionnaires/Rating Scales
• Easy to obtain
• Reflect behavior across settings
• Subject to interviewee/rater bias

Direct Assessment

• Behavioral Observations
• More difficult to obtain
• Reflect behavior within limited settings
• Not subject to interviewee/rater bias

Diagnostic Assessments

The Autism Diagnostic Interview-Revised (ADI-R)

• Semi-structured interview
• Designed to elicit the information needed to diagnose autism.
• The primary focus is on the three core domains of autism (i.e., language/communication; reciprocal social interactions; and restricted, repetitive, and stereotyped behaviors and interests).
• Requires a trained interviewer and caregiver familiar with both the developmental history and the current behaviour of the child.
• The individual being assessed must have a developmental level of at least two years.

Indirect Assessment: Interview

The Autism Diagnostic Interview-Revised (ADI-R)

• The 93 items that comprise this measure takes approximately 90 to 150 minutes to administer.
• Solid psychometric properties.
• Works very well for differentiation of ASD from nonautistic developmental disorders in clinically referred groups, provided that the mental age is above 2 years.
• False positives very rare,
• Reported to work well for the identification of Asperger’s Disorder.
• However, it may not do so as well among children under 4 years of age.
• According to Klinger and Renner (2000): “The diagnostic interview that yields the most reliable and valid diagnosis of autism is the ADI–R” (p. 481).

Indirect Assessment: Interview

DISCO (Diagnostic Interview for Social and Communication Disorders)

• A detailed, semi-structured interview designed to find out about the person's development, behaviour and skills since birth through to their current day-to-day functioning. 
• Its special value is that it collects information using a dimensional approach and concerning all aspects of each individual’s skills, challenges and untypical behaviours, not just the features of autism spectrum disorder.
• The DISCO can be used with children, young people and adults of any age; for any level of ability, for any manifestation of an autism spectrum profile from the most obvious to the most subtle. It can also assist in identifying co-existing conditions often associated with the autism spectrum, such as ADHD, tics, dyspraxia and catatonia-like disorders.

Indirect Assessment: Interview

Consists of four modules.

• Module 1 for individuals who are preverbal or who speak in single words.
• Module 2 for those who speak in phrases.
• Module 3 for children and adolescents with fluent speech.
• Module 4 for adolescents and adults with fluent speech.

A standardized, semi-structured, interactive play assessment of social behavior. Uses “planned social occasions” to facilitate observation of the social, communication, and play or imaginative use of material behaviors related to the diagnosis of ASD.

Direct Assessment: ADOS

Included in the ADOS:

• A construction task
• Make believe play
• Joint interactive play
• Free play
• Snack
• Response to name
• Join attention cue
• Birthday party
• Bubble play
• Description of a picture
• Looking at a book

Direct Assessment: ADOS

• Administration requires 30 to 45 minutes.
• Because its primary goal is accurate diagnosis, the authors suggest that it may not be a good measure of treatment effectiveness or developmental growth (especially in the later modules).
• The ADOS tool differs from the other tools described here as it is not based on developmental data and therefore only looks at current behaviour and skills.
• Psychometric data indicates substantial interrater and test-retest reliability for individual items, and excellent interrater reliability within domains and internal consistency.
• Mean test scores were found to consistently differentiate ASD and non-ASD groups.

Direct Assessment: ADOS

• 15-item structured observation tool.
• Items scored on a 4-point scale ranging from 1 (normal) to 4 (severely abnormal).
• In making these ratings the evaluator is asked to compare the child being assessed to others of the same developmental level.
• Thus, an understanding of developmental expectations for the 15 CARS items is essential.
• The sum ratings is used to determine a total score and the severity of autistic behaviors
• Non-autistic, 15 to 29
• Mildly-moderately autistic 30-37
• Severely autistic, 37

Direct Assessment: CARS

• Data can also be obtained from parent interviews and student record reviews.
• When initially developed it attempted to include diagnostic criteria from a variety of classification systems
• This may have created some problems for its current use

• Currently includes items that are no longer considered essential for the diagnosis of autism (e.g., taste, smell, and touch response) and may imply to some users of this tool that they are essential to diagnosis (when in fact they are not).
• Psychometrically, the CARS has been described as “acceptable,” “good,” and as a “well-constructed rating scale.”
• The agreement between raters for CARS total scores was very large (r (98) = 0.94)

Direct Assessment: CARS

(Bishop & Lord, 2023)

• Studies show that quick diagnostic judgments by expert clinicians lead to high rates of false positives and false negatives (Gabrielsen et al., 2015)
• The ADI-R and ADOS were not developed for individuals with severe vision, hearing, and/or motor impairments, nor are they valid for individuals with profound intellectual disabilities (Lord, Luyster, Gotham, & Guthrie, 2012)
• The ADOS provides a relatively brief observation, during which information about certain behaviours, such as restricted, repetitive, and sensory interests or behaviours (RRBs), or may be difficult to elicit.
• Modifications to typical assessment practices are also required when a child or their family do not speak the same language as the diagnostician, as standardized instruments cannot be validly administered via a translator, or when there is no living parent/caregiver who is familiar enough with the individual’s developmental history to complete an interview like the ADI-R

Issues with diagnosis

(McCrimmon & Rostad, 2014)

The Autism Diagnostic Observation Schedule-Second Edition (ADOS-2)

• Updated protocols with clearer administration and coding guidelines
• A new Toddler Module designed for minimally verbal children ages 12-30 months

ADOS-2 is considered the “gold standard” for ASD assessment

• However, it should be a part of a comprehensive evaluation that considers a person's developmental history, information provided by parents and other key information
• Moreover, behavioural observations both during and outside of the ADOS-2 and the judgement of experienced clinicians are necessary

ADOS-2

Autism.org.uk

Post diagnosis:

• Gaining information
• Incorporating diagnosis into understanding of child

Post-diagnostic support:

• Benefits and positives of support
• Lack of post-diagnostic support
• Active support seeking
• Improvements and desired support

Pre-diagnosis concerns, confusions and dillemas:

• Recognition of child's differences/concerns
• Cofusion guilt and self-blame
• Dismissal of concerns by others
• Dilemma around seeking diagnosis

Diagnostic assessment process:

• Timing
• Communication and interaction with clinicians
• Structure and content of assessment

Reactions to diagnosis:

• Relief
• Distressing emotions
• Gender differences

Parents' experiences of receiving diagnosis

2. Critically evaluate the usefulness of using only the ADOS for diagnosing autism spectrum disorders. What other tools and measures might be useful?

Exam Focus

Any Questions?

Thanks!