Tag: autism

Internal Body Sensing Ability Varies with Age

Photo by Daniil Kuželev on Unsplash

A Chinese study has found that the ability to sense nervous signals such as heartbeat varies with age, peaking in young adulthood, but does not seem to be associated with autism.

Interoception is the ability to process and integrate internal signals originating from one’s body, such as heartbeats and breathing patterns. This ability is important for maintaining homeostasis. Recent findings have suggested that autism spectrum disorders are associated with a wide range of sensory integration impairments including interoceptive accuracy.

However, it is still not clear whether individuals with subclinical features of autism, which only moderately impact daily life, also exhibit similar impairments in interoceptive accuracy. It is also not clear how interoceptive ability and its association with autistic traits varies with age.

In order to address this issue, Dr Raymond Chan’s team from the Institute of Psychology of the Chinese Academy of Sciences (CAS) has developed an innovative paradigm involving eye-tracking measures to examine the multidimensional interoception and autistic traits in different age groups.

In so doing, they recruited 114 healthy university students aged 19–22 and explored the correlations among autistic traits and interoceptive accuracy using an “Eye-tracking Interoceptive Accuracy Task” (EIAT), which presents two bouncing shapes and requires participants to look at the one whiches bounces in time with their heartbeat.

Since this task requires no verbal report or button-pressing, it enables the exploration of interoceptive accuracy in preschool children and individuals with psychiatric disorders or speech impairments.

However, while autistic traits correlated significantly with the ability to describe and express emotion (alexithymia) but not with the different dimensions of interoception such as interoceptive accuracy (performance of interoceptive ability on behavioural tests), interoceptive sensibility (subjective sensitivity to internal sensations on self-report questionnaires) and interoceptive awareness (personal insight into interoceptive aptitude).

They then recruited 52 preschool children aged four to six, 50 adolescents aged 12–16 and 50 adults aged 23–54 to specifically examine the relationship of autistic traits and interoceptive accuracy across these three age groups. The researchers found that interoceptive accuracy evolves from childhood to early adulthood, and then declines with age. The highest average accuracy was seen in 12-16 year olds. The dataset showed that the developmental trajectory of interoceptive accuracy has a reverted U-shape trend peaking around early adulthood.

The findings suggest that interoceptive accuracy significantly differs between typically-developing preschool children, adolescents and adults. The study also highlights the need for future study into preschool children with suspected autism spectrum disorders.

Source: Medical Xpress

Autism Theory Treats its Characteristic Traits as Favoured by Society

For decades, scientists have fruitlessly sought a unifying aetiology for autism and an explanation for its prevalence, but now a new theoretical model describes the condition as a combination of traits that are common in autism and which are socially valued, combined with co-occurring disabilities.

An estimated 1 in 54 people have autism, which has been on the increase in developed countries. TA Meridian McDonald, PhD, a research instructor in Neurology at Vanderbilt University Medical Center, said: “Up until now there have been a lot of theories about the possible causes of autism but none of those theories account for the majority of autism cases. There are also a lot of theories as to why the prevalence of autism has been increasing in the population but, to date, there hasn’t been a theory that provides an explanatory model that accounts for all of those phenomena, including the genetics, social history, or characteristics of autism.”

She has worked on autism for 25 years, culminating in a theory called, “The Broader Autism Phenotype Constellation-Disability Matrix Paradigm (BAPCO-DMAP) Theory”, a focuses on the genetic basis of autism in line with current science but shifts the emphasis to positive traits selected for by events occurring over the past century.”The BAPCO-DMAP theory describes how people are attracted to other people who are very similar. They are attracted to certain traits that are very common in the population, and this leads to offspring who are more likely to have certain traits, as well as a greater intensity of traits,” said McDonald.

“The [BAPCO] traits are not what people expect. They expect the traits to be about challenges or difficulties, but instead there are six main traits—increased attention, increased memory, a preference for the object world vs. the social world and their environment, increased nonconformity, increased differences in sensory and perception, as well as systemising.”

These BAPCO traits are thus not necessarily negative, and can be combined with social skills. Counterintuitively, babies with increased memory and attention spans learn language later, because babies normally rely on their tiny attention span to break words down into their simplest sounds. With greater memory and attention spans, infants engage in echolalia, speaking long phrases without understanding them.

“You can often see children with autism engaging in sense-making activities, such as watching the same show over and over and memorising information,” McDonald said.The BAPCO traits are not by themselves significant impediments, but when combined with a disability such as an information processing disorder, then the combination leads to greater difficulties.

According to McDonald, the increased prevalence of autism in developed countries is due to men and women with BAPCO traits being able to pursue similar careers and passions, as opposed to being limited by circumstance, and results in relationships. This effectively concentrates BAPCO traits in any children they have.Since the BAPCO traits are socially valued, there simply is no “cure” for them, according to McDonald.”When we talk about autism we need to address the developmental disabilities that these individuals are experiencing but also find way to support and enhance their broader autism trait constellations,” she concluded.

Source: Medical Xpress

Journal information: T.A. Meridian McDonald, The broader autism phenotype constellations–disability matrix paradigm: Theoretical model for autism and the broader autism phenotype, Medical Hypotheses (2020). DOI: 10.1016/j.mehy.2020.110456

Unmedicated Autism Associated With Substance Abuse

A Taiwanese study has shown that individuals diagnosed with untreated autism spectrum disorder (ASD) have higher rates of substance abuse compared to those on treatment.

The researchers used inpatient and outpatient data of 6 599 individuals with ASD who had at least 3 outpatients visits for ASD, drawn from the Taiwan National Health Insurance Research Database. They found an increased risk of substance use disorder (SUD) among those who were not receiving medication for ASD (adjusted hazard ratio 2.33, 95% CI 1.89-2.87). The risk for drug abuse was three times higher, and the risk for alcohol abuse was two times higher.

Additionally, those with comorbid SUD had over a three times greater risk of death over a follow-up period of 8.1 years.Those taking psychotropic agents had a 40% reduction for SUD risk when taking one agent, and a 63% reduction with a multiagent.

There were several comorbidities of psychiatric disorders seen in patients with ASD, such as intellectual disability, attention deficit hyperactivity disorder, tic disorder, epilepsy, obsessive-compulsive disorder, mood disorder, anxiety disorder, and impulse control disorder. However, individuals with ASD had a higher risk of SUD even compared with matched controls with the same comorbidities. SUD risk was highest with certain comorbidities; untreated ASD with comorbid tic disorder was 6 times higher; with a comorbid impulse control disorder, it was five times higher.

The researchers stated that these are critical findings, but of limited use due to the “umbrella term” of substance use disorder, and further studies will be needed to examine the specific types of drug use amongst individuals with ASD. Future research could investigate whether non-pharmaceutical treatments such as behavioural therapy had the same effect.They conclude that screening  individuals with ASD for SUD is important, given the findings of the study.

Source: MedPage Today

Journal information: Huang J, Yang F, Chien W, et al. Risk of Substance Use Disorder and Its Associations With Comorbidities and Psychotropic Agents in Patients With Autism. JAMA Pediatr. Published online January 04, 2021. doi:10.1001/jamapediatrics.2020.5371