Most autistic children do not experience cognitive delays and they develop speech at similar times as their non-autistic peers. In fact, some autistic children speak earlier than average and do not miss major developmental milestones.
The main characteristics of many autistic children include:
- intensity of focus
- overwhelmingly high emotional empathy and distress in response to others’ pain
- differences in social preferences such as wanting to hang out with one person at a time or in small groups
- sensory differences — being either very sensitive or under-responsive to touch, taste, smell, noise, and so on
These characteristics go against the stereotype that a person must have all of the “classic” traits of autism in order to be diagnosed.
Even with vast improvements in autism diagnosis over the past few decades, resulting in more and earlier diagnoses, children are still falling through the diagnostic cracks. One main problem is that the available diagnostic tools are not sensitive enough to capture the many ways that autism can present.
Our Current Screening Tools Miss Subtle Presentations of Autism
A recent study published in BJPsych Open found that common ways of screening for autism at three years of age are only effective in diagnosing those with significant cognitive delay (IQ below 70).
Using data from the Norwegian Mother, Father and Child Cohort Study, the researchers found that an autism assessment tool identified only one in five autistic children. This finding suggests that toddlers with level one autism (formerly known as high functioning autism or Asperger’s syndrome) would likely not be diagnosed through the use of available screening tools at this age.
While the assessment tool had high specificity, meaning that there were very few false positives, the ability of the tool to detect autism was too low.
A person cannot suddenly develop or “catch” autism. Autistic individuals are born autistic. Autism is a genetic or inherited neurodevelopmental difference. Characteristics of autism are evident from an early age, usually in the first two years of life. These characteristics are often so subtle that they would not be obvious in healthcare settings.
Additionally, autistic traits are so varied that no two autistic individuals are alike, in the same way that non-autistic traits are so varied that no two non-autistic individuals are alike.
The BJPsych Open study stated:
A critical challenge in autism screening is the lack of a clear boundary between the autism spectrum and the normal range of development. Autistic traits are continuously distributed in the population. The threshold for receiving a diagnosis depends on clinical judgement, which may vary between clinicians and change over time. In screening, the symptom scores of children with ASD may also overlap with those of other children. These features of the disorder suggest that it does not easily lend itself to detection by screening, at least not for children without general developmental delay.
This means that early universal screening may not be useful or cost effective. Most parents seek diagnosis or assessment if they have concerns about their child. Perhaps emphasis should be placed on developing better screening measures for assessing autism in older children. Or more could be done to detect characteristics of level one autism at younger ages.
Since undiagnosed autism is associated with mental health challenges and risk of suicide in adulthood, early diagnosis can increase understanding and help autistic individuals access support.