When she was growing up, Amber Dubiel, OMS I, found that communicating with her younger stepbrother was sometimes an exercise in patience. Her stepbrother, who has autism, is nonverbal and uses sign language to communicate. Prompted verbally to put on his shoes, he might listen, pause and reach for his backpack instead.
“When I was younger, that was sometimes a little frustrating, because I knew he knew what shoes were,” says Dubiel, who attends the Lake Erie College of Osteopathic Medicine-Bradenton (Florida). Now she has new insight into her stepbrother’s behavior after assisting with a research project led by Randy J. Kulesza Jr., PhD, a professor at the Lake Erie College of Osteopathic Medicine (LECOM) in Erie, Pennsylvania.
Dr. Kulesza and Dubiel co-authored a paper on the research, which used an animal model to examine how autistic individuals process sound. Their paper was recently published in the journal Neuroscience.
Analyzing auditory processing
In 2013, Dubiel, who was completing a master’s in biomedical science at LECOM, began assisting with Dr. Kulesza’s research on how autism spectrum disorder affects auditory processing. The study involved comparing a control group of rats with another group that had prenatal exposure to valproic acid (VPA), which is used as an animal model for autism spectrum disorder.
After both groups of animals had listened to very simple sounds for an hour, the researchers compared neuron activity in the rats’ auditory brainstems, which allowed them to analyze how well sound input traveled from the rats’ ears to the brainstem.
The two groups of rats processed the sounds very differently. “We found that compared to the control rats, the VPA-exposed rats’ neurons were hypersensitive to sound stimuli and their neuronal response was less organized,” Dubiel explains.
Dr. Kulesza compares those rats’ auditory processing to the picture on a grainy television set. “If you have more pixels, you have higher resolution and a nice, clear picture on your TV screen,” he says. “If you imagine the auditory system of the VPA-exposed rats as a TV, there would be fewer pixels and the resolution would be low.”
Implications for humans
Dr. Kulesza and Dubiel believe the rats’ abnormal auditory processing may mirror that of people who have autism spectrum disorder. “We hypothesize that the hyperstimulation and disorganized pattern of neuron firing we observed in the VPA-exposed rats are what cause the auditory defects that are often seen in autistic individuals,” Dubiel says. For humans, she notes, even slight disorganization in the auditory brainstem could make it difficult to differentiate between similar-sounding words like cat, bat, mat and gnat.
Among individuals with autism spectrum disorder, auditory dysfunction is relatively common. Ultimately, Dr. Kulesza says, the goal of the research is to eventually give clinicians another tool to use when diagnosing autism spectrum disorder.
“We’ve examined the brain of kids as young as two years old, and we see this disorganization in certain auditory centers,” he explains. “So we think in the first days of life, it might be possible to use the auditory system as a diagnostic tool so that a child who has autism could get started with therapies early.”
Dubiel says the research has given her new insight into communicating with her stepbrother. It helped her understand why he responds better when family members use sign language to reinforce speech.
“Being part of this research was really rewarding because of my personal connection to autism,” she says. “It’s provided a lot of interesting explanations that, in hindsight, help me understand why my stepbrother was acting the way he was.”