A newly designed device can give caregivers warning of an impending aggressive outburst from a person with ASD one minute before it occurs

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What would you do if you could predict the future a minute in advance?

That might not seem like a long time, but for caretakers of people with autism, knowing what will happen 60 seconds from now could be enough time to prevent an aggressive outburst.

To alert caretakers when stress levels are nearing the point of an aggressive episode, Northeastern behavioral scientist Matthew Goodwin has created a wearable wrist device for people with autism that monitors physiological indicators of stress.

People with autism are prone to aggressive outbursts because their resting levels of stress are much higher than someone without autism.

“Their arousal levels are already at the ceiling,” says Goodwin, an associate professor with joint appointments in Bouvé College of Health Sciences and the Khoury College of Computer and Sciences. “It takes very little to cross the tipping point.”

On top of that, it’s often difficult, if not impossible, for people with autism to communicate what’s distressing them.

This makes it especially hard for caretakers to act preemptively, which is why an automatic warning signal such as Goodwin’s would be helpful, even if it’s only a 60-second head start.

“If we could give caregivers advance notice, it would prevent them from getting caught off guard and potentially allow them to relax the individual and make sure everyone in the environment is safe,” Goodwin says.

The device monitors heart rate, sweat production, skin surface temperature, and arm movements.

During a study, Goodwin and his team of researchers observed 20 children with autism who have aggressive episodes.

Over the course of 87 hours, they tracked each episode and the corresponding physiological changes.

That information was then synchronized with a clock in the biosensors the children wore.

This allowed researchers to match each aggressive episode with the bodily changes that occurred before, during, and after.

This shows the device

The device monitors heart rate, sweat production, skin surface temperature, and arm movements. The image is adapted from the Northwestern news release.

Based on these 20 samples, Goodwin can predict an aggressive outburst a minute in advance with 84 percent accuracy.

“But those aren’t magic numbers. Those are just limitations of our data set,” Goodwin says. “As our data set grows and we use more sophisticated machine learning models, I think we might get more than 60 seconds.”

With the help of funding from the Department of Defense, the Simons Foundation and the Nancy Lurie Marks Family Foundation, Goodwin will expand his sample size to 240 individuals with autism who behave aggressively.

“Families with children who act aggressively tell us that they don’t know what causes these outbursts, and they’re fearful it could happen anytime, so they self-impose house arrest,” Goodwin says.

“They don’t go to the movies. They don’t go to the grocery store with their kids.

They don’t go to parks.”

Goodwin hopes to eliminate these fears by providing some clarity of the future.

“Some parents say that even if we can only give them 60 percent accuracy, that’s better than chance, which is what they’ve got now,” Goodwin says. “They say that would be priceless.”


utism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by persistent difficulties in social communication and social interaction, coupled with restricted, repetitive patterns of behavior or interest.1 

Children with ASD may present with additional maladaptive behaviors, including aggression, self-injury, and severe tantrums (also referred to in this text as irritability), which researchers suggest can cause families greater stress than the core features of ASD.2,3

Defining aggression

Aggression is generally characterized as behavior that is threatening or likely to cause harm and may be verbal (eg, threatening or cursing at another person) or physical (eg, hitting, biting, or throwing objects at another person).

A person can demonstrate one form of aggressive behavior or many, with variable frequency, intensity, and duration. Because of the variable nature of aggressive behavior, researchers have defined aggression in many different ways.

For example, the Aberrant Behavior Checklist Irritability subscale (ABC-I),4 the responses on a computer task showing aggressive stimuli,5 the aggression subscale of the Child Behavior Checklist,6,7 and the behavior recordings noted during experimental analysis of behavior8 all capture slightly different aspects of aggression.

This variability creates challenges in comparing aggression between individuals and across research studies. In response, researchers are increasingly utilizing multiple measures and methods of defining aggression, which may ultimately allow for clearer interpretation of data and improve ease of comparison.

Prevalence

Research indicates that rates of aggressive behavior may be higher in individuals with ASD compared to typically developing peers and those with other developmental disabilities, though this is inconsistently reported in the literature.

In some studies, individuals diagnosed with intellectual disability (ID) and comorbid ASD are reported to more frequently demonstrate aggression than individuals with ID alone.9,10 In contrast, one study reports that a group of younger children with ASD showed less aggression compared to a control group of age-matched children, although older children with ASD in this study demonstrated higher aggression rates.6

Furthermore, ASD-specific research has yielded variable aggression prevalence rates. Kanne and Mazurek11 demonstrated that 56% of individuals with ASD (n=1,380) directed aggression toward caregivers and 32% directed aggression toward noncaregivers. In addition, 68% of these individuals had a history of directing aggression toward caregivers, and 49% had a history of directing aggression toward noncaregivers.11 

Other studies found a lower prevalence of aggression in ASD. In a population of adults with ID and comorbid ASD, 15%–18% were found to engage in aggression toward others.12 

Scores in the clinically significant range for aggression on a broad behavioral measure were found in 22% of young children diagnosed with autistic disorder in another study.7 In a population of children with an educational diagnosis of pervasive developmental disorder, between 9% and 14% were reported to exhibit aggression.3

Aggression risk factors

Certain factors, such as young age, tend to predict aggression levels for children in the general population.13,14 In ASD, however, risk factors may be unique from those identified in typically developing or developmentally disabled children.

For example, in typically developing children, boys tend to exhibit aggression more frequently than girls;13 however, sex has not been found to predict the frequency of aggression in ASD.6,7 

Likewise, social factors (ie, level of parent education and marital status) that predict aggression in typically developing children have not been consistently predictive of aggression in children with ASD.11 Specific features of ASD may drive aggressive behavior. Reese et al15 found that children with ASD frequently engaged in aggression to gain access to ritualistic or repetitive behaviors. Language ability, intellectual quotient, and adaptive functioning also have been implicated as predictors of aggressive behavior in children with ASD.7,16

Negative outcomes related to aggression

Aggression is clearly associated with negative outcomes for children with ASD, including impaired social relationships,17 placement in restrictive school or residential settings,18 use of physical intervention,19 and increased risk of being victimized.20 

Aggressive behaviors can also contribute to school provider burnout,21 leading to probable impact on the quality of education.

Aggression also contributes to negative outcomes for caregivers of youth with ASD, including increased stress levels,22 financial problems, lack of support services, and negative impact on day-to-day family life and well-being.23 Clearly addressing aggressive behavior is pivotal to improving outcomes for individuals with ASD and their caregivers.


Source:
Northwestern University
Media Contacts: 
Emily Arntsen – Northwestern University
Image Source:
The image is adapted from the Northwestern news release.

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