Autism Spectrum Disorder (ASD): Causes, Symptoms, Types & Tests

Autism Spectrum Disorder (ASD) represents a neurological and developmental condition that impacts communication, interaction with other people, learning, and behavior. Autism is referred to as a spectrum as individuals can experience it differently and require degrees of support. Differences in people's abilities may mean that some autistic individuals require substantial ongoing support whilst others can be supported relatively well and live independently.

The signs of autism typically appear early in childhood, but at times symptoms may stand out as a child becomes older and more socially or communicatively challenged. Identifying developmental differences early on can help to inform families of a need for evaluation and support.

Diagnostic services are offered to support healthcare evaluation at Molecular Diagnostics and Therapy when recommended by a medical professional. Today, in this blog, we are going to discuss Autism Spectrum Disorder, symptoms of autism, autism spectrum disorder causes, ASD types, autism tests, and how autism is evaluated.

What Is Autism Spectrum Disorder?

ASD is a developmental disorder that impacts communication, social interaction, behavior, and patterns of interests or activities. The Centers for Disease Control and Prevention (CDC) identify social communication and interaction differences and restricted and repetitive behaviour or interests as characteristics of those with autism.

Autism affects people for a lifetime. In an individual's life, however, how it impacts them may vary, and support (including education, behaviour, communication, and others) may be appropriate to help this person learn skills and engage in daily activities. There are no universal symptoms or behaviors for autism. People with autism have a wide range of abilities, challenges, interests, and needs for support.

Autism Spectrum Disorder Symptoms

The autism spectrum disorder symptoms can vary considerably from one person to another. Some children may show signs during infancy or toddler years, while others may be identified later. Common characteristics may include:

• Difficulty with back-and-forth communication or social interaction
• Difficulty understanding or using gestures, facial expressions, or eye contact
• Delayed or different language development
• Repeating words or phrases
• Repetitive movements such as hand flapping or rocking
• Strong preference for routines or difficulty with unexpected changes
• Highly focused interests
• Unusual sensitivity or reduced sensitivity to sounds, lights, textures, smells, or other sensory experiences
• Difficulty developing or maintaining social relationships

Not everyone who has autism exhibits all these traits. Some may excel in language development and struggle socially; others may have considerable difficulty with communication. These characteristics can also occur in people without ASD, so a comprehensive evaluation is needed.

Early Signs of Autism

Some early signs might be detected during the first few years. They may respond limitedly to their name, use fewer gestures, have limited eye contact, have difficulty sharing their interests with others, have delayed speech, or have repetitive behaviours. Some children may even seem to forget the skills they previously learned in language or social skills.

Development is different for every child, though, and children with developmental differences may not be autistic. If parents/caregivers have concerns about a child's communication, behaviour, learning, and/or social development, it is important to discuss these concerns with a pediatrician or qualified healthcare professional so that an evaluation can be determined if additional support is required. 

Autism Spectrum Disorder Causes

The causes of autism spectrum disorder are not completely known. ASD has multiple contributing causes. Genetic factors play an important role, while certain environmental or prenatal/perinatal factors may affect likelihood. There are some changes in the genes and some genetic conditions that are linked to a higher risk for autism. Factors that could have an effect on early brain development are also being researched. Some prenatal and perinatal risk factors are associated with a higher risk of ASD, but these factors do not imply that a child has ASD. There isn't a single reason for autism, and poor parenting doesn't cause autism.

Is Autism Genetic?

Autism has a strong genetic component, and genetic factors can be inherited or arise through other genetic changes. However, ASD usually does not follow a simple pattern of inheritance. Some autistic individuals are found to have a specific, identifiable genetic condition, and for other individuals, no one particular gene is known to be the cause. If a family member has autism, this does not mean that all children are at risk. Genetic testing may sometimes be part of a comprehensive medical investigation, especially if other developmental, neurological, physical, or other tests are abnormal.

How Is Autism Diagnosed?

No one blood test, brain scan, or laboratory test can be used to diagnose Autism Spectrum Disorder. The diagnosis relies primarily on a thorough history with regard to development, behaviour, communication and social interactions. Healthcare professionals can conduct parent/carer interviews, observe the child, and utilize the child's developmental or autism-specific assessments.

Depending on the needs and age of the person, a comprehensive evaluation may include an assessment in many different areas by professionals from each of those areas. They can be other qualified health care providers, including occupational therapists, speech-language professionals, psychologists, psychiatrists, pediatricians, and developmental specialists.

Autism Tests and Screening

There are screening tests and diagnostic tests for autism. Screening is not a diagnosis. A screening tool determines if a child has some characteristics that could be related to autism and might require more examination. Not definitive of a child's ASD. The Modified Checklist for Autism (M-CHAT) in Toddlers with follow-up (M-CHAT-R/F) is one commonly used screening tool for toddlers. There may be other screening or assessment instruments employed in other contexts and ages. A detailed developmental evaluation is recommended if screening indicates additional testing is warranted. 

Developmental Evaluation for Autism

A developmental evaluation looks at different areas of a person's development and functioning. The healthcare professional may assess:

• Communication and language
• Social interaction
• Behaviour
• Learning and cognitive abilities
• Play skills
• Adaptive or daily living skills
• Sensory responses
• Motor development

Information from parents, caregivers, teachers, or other people who regularly interact with the child can also be useful. The evaluation helps healthcare professionals understand the individual's strengths and challenges rather than relying on a single test result.

Is There a Blood Test for Autism?

None of the blood tests are currently recommended for the routine screening of autism. Additional tests such as a blood test or genetic test may sometimes be suggested to look for other conditions that could be causing the developmental difference or to find out other genetic reasons for developmental delays. These tests do not, however, provide diagnostic confirmation of, or exclude, ASD. Much in the same way, magnetic resonance imaging (MRI) of the brain is not routine for the diagnosis of autism. It may be suggested if a health care professional identifies a person's symptoms as possibly being caused by another neurological disorder, or because of certain clinical indications.

Can Autism Be Diagnosed in Adults?

Yes. It is possible to diagnose autism in adults. Some children may have the diagnosis before they are diagnosed as an adolescent or adult. Adults who have longstanding challenges with social communication, sensory experiences, routines or repetitive behaviours may request an assessment.

In general, adult autism assessment includes the comprehensive inclusion of developmental history, as well as current features. Wherever possible, information about childhood development is also useful. A late diagnosis does not mean that autism has come up in recent times. Autism is a developmental disorder, but the symptoms may be more apparent at different ages.

Why Early Evaluation Matters?

Recognising developmental differences at an early stage can support both the family to understand their child's needs and to access support. This can involve the provision of speech and language therapy, occupational therapy, educational support and behavioural interventions, social skills support and other individualised support. Support varies for each individual as a function of the support needed to match the strengths, needs, and aspirations of the individual. The aim of evaluations is not to restrict a person's abilities but to make sense of how they are able to communicate, learn, interact, and 'be' in the world.

Diagnostic Support at Molecular Diagnostics and Therapy

Molecular Diagnostics and Therapy provides diagnostic services to help assess various medical conditions in case a diagnosis is clinically indicated. Diagnosis of Autism Spectrum Disorder is largely based on developmental and behavioural assessment, and is not strictly based on a laboratory or imaging test. Some other tests might be ordered, however, when necessary, to help diagnose other health or genetic problems that the individual may have when there is suspicion of other developmental issues of concern. The selection of the appropriate assessment required to determine the status and needs of the individual should always be made based on their symptomatology, developmental history, and clinical requirements.

Conclusion

ASD is a developmental disorder that can impact communication, social interaction, behaviour, sensory experiences, and patterns of interests. Autism can appear very differently for every person, so autism is termed a spectrum of symptoms. Despite there being no full consensus on the exact causes of autism spectrum disorder, several studies have suggested the genetic and developmental mechanisms are important. Autism is currently classified as a single autism spectrum disorder rather than separate DSM-IV subtypes.

Autism evaluation may include developmental screening, detailed developmental history, clinical assessment, behavioural observation, and standardized diagnostic tools. As of yet, there is no single blood test or imaging scan that can be used to definitively diagnose autism. Some situations may suggest additional genetic or medical tests to explore other conditions of interest. In Molecular Diagnostics and Therapy, diagnostic services are provided for proper medical evaluation on the recommendation of a health care professional. If you are worried about a child or adult's behaviour, learning, or communication, having an evaluation can help determine their needs and can help direct or inform support.