NDIS and intellectual disability: the role of cognitive assessment

A cognitive assessment is often a key part of the evidence for an NDIS application based on intellectual disability. But an IQ score on its own does not tell the full story, for the diagnosis or for the NDIS.

This guide explains how intellectual disability and the NDIS fit together. It covers what intellectual disability is, what a cognitive assessment involves, and what the National Disability Insurance Agency (NDIA) looks for. It is general information, so please speak with a qualified professional about your situation.

What is intellectual disability?

Intellectual disability is a lifelong condition that affects learning, reasoning and everyday skills. Under the DSM-5, the diagnostic manual used by clinicians, it involves three things:

1. Differences in intellectual functioning, such as reasoning, problem-solving, planning and learning. These are measured with standardised intelligence tests.
2. Differences in adaptive functioning, which means the practical, social and conceptual skills people use in daily life.
3. Onset during the developmental period, meaning childhood or adolescence.

A review in Current Opinion in Psychiatry notes that DSM-5 defines the severity levels (mild, moderate, severe and profound) based on adaptive functioning, not IQ scores. This is because adaptive functioning shows how much support a person needs.

وہ بچوں کی پرورش کا نیٹ ورک explains that diagnosis involves formal IQ testing, and that a trained psychologist does the testing and diagnoses intellectual disability.

How the NDIS treats intellectual disability

The NDIS disability requirements include intellectual impairment. The NDIA describes this as differences in intellectual function that affect how you think, plan and learn, make judgements, solve problems and reason, and that affect everyday life skills.

The NDIA’s Applying to the NDIS guideline uses lists of conditions to help with decisions:

• List A includes intellectual disability diagnosed and assessed as moderate, severe or profound under current DSM criteria. People with a List A condition will likely meet the disability requirements.
• List B includes intellectual disability more broadly. For List B, the NDIA will likely accept that the impairment is permanent, but you still need evidence that it substantially reduces your ability to do everyday tasks.

This means that for people with a mild intellectual disability, functional evidence is especially important. You still need to meet the age and residence rules.

ادراکی جائزے میں کیا شامل ہوتا ہے

A cognitive assessment for intellectual disability usually has several parts.

Background and history

The psychologist asks about development, schooling, health, family history and daily life. They may read school reports, earlier assessments and medical letters. For adults, this history helps show that difficulties began in childhood.

Intellectual testing

Standardised intelligence tests measure skills such as verbal reasoning, visual problem-solving, working memory and processing speed. Scores are compared with people of the same age. The overall result is only one part of the picture. The pattern of strengths and challenges is often more useful.

Adaptive functioning

Adaptive functioning is usually measured with a standardised questionnaire or interview completed with someone who knows the person well. The NDIS lists the Vineland Adaptive Behavior Scales (Vineland-III) as one example tool for intellectual disability. It looks at communication, daily living skills and socialisation.

Feedback and report

The report should explain the results in plain language, give a diagnosis if the criteria are met, and describe practical supports. For the NDIS, it helps if the report also links results to the six everyday areas: communicating, socialising, learning, moving around, self-care and managing your life.

Getting an accurate result

Test scores can be lowered by things that have nothing to do with intellectual ability. A careful assessment considers:

• anxiety, low mood or trauma
• hearing or vision problems
• English as a second language, or limited schooling
• cultural background and familiarity with testing
• tiredness, illness, pain or medication effects
• other conditions such as autism, ADHD or a brain injury.

If any of these apply, tell the psychologist before the assessment. They may adjust how testing is done or use an interpreter. They should also explain in the report how these factors may have affected results.

When results sit near the cut-off

Some people have scores that are low but above the range for intellectual disability. This is sometimes called borderline intellectual functioning. It is not a diagnosis of intellectual disability. People in this range can still have real support needs, and a report can describe those needs clearly.

Preparing for the assessment

A little preparation helps the day go smoothly and gives the most accurate picture of a person’s abilities.

• Gather school reports, earlier assessments, medical letters and any NDIS or school support plans.
• Bring glasses or hearing aids if they are used.
• Get a good night’s sleep and eat beforehand. Bring snacks and water.
• Ask a family member or support person who knows daily life well to take part in the interview or questionnaires.
• Let the clinic know about any support needs, such as an interpreter, extra breaks or a quiet room.

For children, it can help to explain that they will do puzzles and answer questions, and that no one gets everything right. Adults can be reassured that the aim is to understand how they think and learn, not to pass or fail.

Using the report for an NDIS application

The report is most useful to the NDIA when it covers more than test scores. Where possible, it should:

• state the diagnosis and the severity level, with the criteria used
• describe adaptive functioning with a standardised measure
• give real examples of support needed in each of the six everyday areas
• comment on whether the impairment is likely to be lifelong.

Pair the report with evidence from other professionals who know the person over time, such as a GP, paediatrician, teacher or therapist.

Young children and the NDIS

For very young children, clinicians often describe developmental delay rather than intellectual disability, because early test results can change as children grow. The NDIS early intervention requirements allow children younger than 6 with developmental delay to be considered. For children younger than 9, the NDIS early childhood approach is the usual first step.

The NDIS rules are changing. The NDIA says that from 1 January 2028, access decisions for new applicants will use a new standardised assessment of functional capacity. See the Securing the NDIS for Future Generations page for updates.

Invictus Health کیسے مدد کر سکتا ہے

Our psychologists and neuropsychologists provide cognitive assessments for children, teenagers and adults. Our IQ, memory and giftedness assessments measure intellectual functioning, and our paediatric neuropsychology service assesses children’s learning and development.

We also provide NDIS کے جائزے اور رپورٹس that include adaptive functioning and describe everyday impact. See our fees page for costs.

An assessment adds information. It does not guarantee a diagnosis, NDIS access or funding.