Isaac Newton, Albert Einstein, Charles Darwin—what unites these three exceptional individuals? It is widely accepted that all three were geniuses, but there is something else. These days, neuroscientists believe that all three suffered from a specific neurological disorder called Asperger’s syndrome.

The whole definition of the term “neurological disorder” implies that something is going wrong in the brain. However, there is a growing recognition of the fact that when it comes to the processes in our brain, “going wrong” does not necessarily mean “going bad”. Our brain is too complicated a mechanism to be interpreted in simplistic terms. Some neurological disorders produce a peculiar state of mind often associated with high artistic and scientific achievements.

Asperger’s Syndrome (AS) is a developmental and neurological disorder that is often associated with symptoms of social withdrawal, motor clumsiness, and impaired communication skills. The Diagnostic and Statistical Manual of Mental disorders (DSM-5) classified AS in the same category as Autism Spectrum Disorder (ASD). It is often referred to as ‘High-functioning’ Autism (HFA), as individuals with AS are more intellectually capable and show less severe abnormalities compared to ASD subjects.

The story of AS and autism started in the 1940s, when two Viennese Scientists, Leo Kanner and Hans Asperger, described a syndrome observed in some children, with the unique characteristics of social isolation, impaired communication skills, and restrictive and obsessive interests. Both scientists used the term ‘autistic’ in their reports. While Kanner’s syndrome was published right away in 1943, Asperger’s report was written in German and remained undiscovered until 1991 when it reappeared in Uta Frith’s textbook Autism and AS.

Research and publications on Asperger’s syndrome reached its peak during 2000-2012. Different research groups proposed a set of criteria for AS diagnosis. While several of these criteria were overlapping, WHO’s International Classification of Diseases and Disorders set the following key characteristics that can be diagnostic for Asperger’s Syndrome:

• Qualitative social impairment involving dysfunctional social adaptivity, impaired non-verbal communication for interaction and lack of social reciprocity.
• Restrictive pattern of interest, motor clumsiness, repetitive behavior, and extreme obsessiveness to specific rituals.
• AS patients must show age-specific, normal cognitive and linguistic development.

Interestingly, the father of Asperger Syndrome, Hans Asperger, described AS patients to be characteristically distinct from ASD subjects. He characterized them as intellectually-able, abstract-loving, and even overachieving in some specific cognitive domains.

Decades after Asperger’s observation, recent studies have also found that AS patients often demonstrate high verbal IQ, strong grammatical skills and they often outperform others in fluid reasoning although they are reported to show a delayed reaction time with poor performance IQ, specifically in symbol coding and processing speed.

Surprisingly, AS is more common than classical autism. Epidemiological surveys report that about 4 out of every 10,000 children are autistic whereas about 25 out of 10,000 children are diagnosed with AS. AS is more common in boys than girls. No scientific explanation behind this observation exists at present.

Like with many other syndromes, no single specific cause is responsible for AS. Rather, a milieu of factors is associated with its development.

Children diagnosed with AS show a genetic pattern, like in autism, where at least one of the parents (most often the father) is diagnosed with AS or at least have some hallmark AS characteristics. The relatives of AS children are known to have anxiety or depression related disorders.

An important causal factor behind the development of AS might be the altered level of neurotransmitters. In AS patients, higher levels of N-Acetyl Aspartate/Choline (precursor of acetylcholine) intake and increased dopamine levels were reported, suggesting an overall altered dopaminergic neurotransmitter composition in major areas of the brain. Intranasal injection of oxytocin, a neuropeptide, was shown to improve facial emotion recognition abilities in AS patients.

Apart from alterations in neurotransmitter levels, neuroimaging studies show that there are structural changes in major areas of the brain that could be associated with the development of Asperger’s Syndrome. Altered grey and white matter volumes were observed in major brain regions, and an abnormal thickness of the hippocampus, amygdala, and anterior cingulate cortex was reported to be the major contributing factor for dysregulated cognitive functions in AS.

Some researchers also proposed that environmental factors can contribute indirectly to the development of AS. Viral or bacterial infection and smoking during pregnancy particularly increases the risk factor, although no concrete evidence supporting these views was found.

Due to the substantial number of overlapping similarities between Asperger’s Syndrome and Autism, it is very easy to confuse one with the other.

Studies in recent decades showed differences between AS and ASD on both quantitative and qualitative levels. The AS subjects displayed age-specific or earlier verbal development, meticulous speech ability, higher desire for social reciprocation, and supreme imagination compared to ASD patients.

On a cognitive level, AS subjects are more perceptive, they possess superior verbal performance and visual-spatial ability compared to ASD patients.

But the major limitations of these studies is the huge variability within the study groups and contradictions in the data patterns, as with age, the distinction between AS and ASD significantly reduces. It is particularly difficult to categorize AS from other disorders as there are no known biomarkers specific to AS only.

As there is not sufficient evidence of distinguishable characteristics for AS that can class the syndrome as ‘one biologically and clinically diagnosed entity’, the DSM-V in 2013 revised and categorized Asperger’s Syndrome as another variant of ASD. Although this decision was criticized by the scientific community, most of the researchers agreed that there is a need to conduct more studies that could help in distinguishing AS from other ASDs.

The most general misconception about Asperger’s syndrome or, as a matter of fact, about autism spectrum disorders in general, is that they develop because of poor parenting and a lack of bonding between parents and their child. This concept was even termed as ‘Refrigerator Mother’ to describe cold and distant parenting. But this notion was challenged from the 1960’s when research on these neurological disorders started to grow and scientists found that it is not parenting, but rather the genetic and neurological makeup of the child that is responsible for these syndromes. Even today, the belief that neurodevelopmental disorders are caused by a traumatic childhood are common. The reality, however, is more complicated than our guesses based on limited information.

References

Barahona-Correa, J. B. and C. N. Filipe (2015) A Concise History of Asperger Syndrome: The Short Reign of a Troublesome Diagnosis. Front Psychol 6: 2024. doi: 10.3389/fpsyg.2015.02024

Faridi, F. and R. Khosrowabadi (2017) Behavioral, Cognitive and Neural Markers of Asperger Syndrome. Basic Clin Neurosci 8(5): 349-359. doi: 10.18869/nirp.bcn.8.5.349

Weiss, E. M., B. Gschaidbauer, et al. (2017) Age-related differences in inhibitory control and memory updating in boys with Asperger syndrome. Eur Arch Psychiatry Clin Neurosci 267(7): 651-659. doi: 10.1007/s00406-016-0756-8

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