What is Autism?

Autism spectrum disorder (ASD) is a neurological and developmental disability that influences one’s ability to interact, communicate, behave, and learn. Autism refers to a wide range of disorders associated with neurodevelopmental difficulties. The 5 primary types of autism includes: Asperger’s syndrome, pervasive developmental disorder, childhood disintegrative disorder, and Rett syndrome.

“Many Successful Persons Live Well with Asperger’s Syndrome. Find out Why!” Icloudhospital.com, 2023, icloudhospital.com/articles/many-successful-persons-live-well-with-asperger%27s-syndrome.-find-out-why! Accessed 8 Apr. 2023.

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Level 1 Autism spectrum disorder (or Asperger’s syndrome)

Individuals diagnosed with Level 1 Autism spectrum disorder have above average intelligence and strong verbal skills, but experience struggles with social communication. Some of the most common symptoms associated with this disorder are:

Inflexibility in behavior and thought
Challenges in switching between activities
Executive functioning problems
Inability to express feelings in speech
Difficulties with social intearctions

Pervasive Developmental Disorder
- not otherwise specified (PDD-NOS)

This is a mild type of autism with a wide range of symptoms involving difficulties with social and language development, delays in language development, walking, and other motor skills.

Gitig, Diana. “The Connections in Autistic Brains Are Idiosyncratic and Individualized.” Ars Technica, Ars Technica, 24 Jan. 2015, arstechnica.com/science/2015/01/the-connections-in-autistic-brains-are-idiosyncratic-and-individualized/. Accessed 8 Apr. 2023.

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Rett Syndrome

Rett syndrome is a rare type of neurological and development disorder that mostly affect girls, though it has been observed in boys as well. This syndrome affects almost every aspect of a child's life, where the common symptoms are: loss of standard movement and coordination, difficulties with communication and speech, and breathing difficulties.

Childhood Disintegrative disorder (CDD)

Childhood Disintegrative Disorder (CDD) is also known as Heller’s syndrome or disintegrative psychosis. This disorder is associated with delayed onset of developmental problems in language, motor skills, or social function. It is more commonly diagnosed in boys, only 1 out of 10 cases will be a girl. Symptoms and regression start to occur in more than two developmental aspects of life, causing the loss of various skills like: acquired language of vocabularies, social skills, certain motor skills, adaptive behaviors, and toileting skills.

Kanner's Syndrome

Characterized by psychiatrist Leo Kanner of John Hopkins University in 1943 as "Infantile autism", Kanner's syndrome is known as the classic autistic disorder. Individuals with Kanner's syndrome appears attractive, alert, and intelligent. However, they also have lack of emotional attachment with others, communication and interaction challenges , uncontrolled speech, obsession with handling objects, and high degree of rote memory and visuospatial skills with major difficulties learning in other areas

For more information on the different types of Autism Spectrum Disorder, click here:
https://www.integrityinc.org/what-are-the-5-types-of-autism/#:~:text=There%20are%20five%20major%20types,developmental%20disorder%20%E2%80%93%20not%20otherwise%20specified.

Brain Structural Differences in Autism

Which brain areas are structurally different between autistic and non-autistic people?

The observation of structural distinctions and differences in autistic people have been aided with the use of Brain imaging technology called magnetic resonance imaging (MRI).
Studies have shown that Children and adolescents often have enlarged hippocampus (region of the brain responsible for memory formation and storage)
Structural changes in amygdala size, though involves conflicting results from different researchers
- Some with autism have smaller amygdalae, some found that autistic children have enlarged amygdalae in early development, difference levels off over time
Decreased brain tissue density in cerebellum region, according to a meta-analysis of 17 imaging studies
- cerebellum region is associated with movement coordination, cognition, and social interaction
Different pattern of thickness of the brain in people with and without autism

For more information on the brain structural changes in Autism Spectrum Disorder, click here:
https://www.spectrumnews.org/news/brain-structure-changes-in-autism-explained/#:~:text=Others%20have%20found%20that%20autistic,of%2017%20imaging%20studies5.

How does age development play a role in these structural differences?

Some infants that are later diagnosed with autism have unusually fast growth in certain brain regions
Cortex seems to expand too quickly in infancy and early childhood, even before autism traits can be detected behaviorally
Late childhood, neurotypical brains continue to grow in size, begin to shrink throughout adulthood