In the United States, about 2 million individuals are dealing with a loss of language ability known as aphasia. Caused by brain injury, Parkinson’s disease, various neurological conditions and most commonly stroke, aphasia can affect anyone at any age. 

The prognosis for a person with aphasia can be hard to predict. Some people regain language abilities in a matter of months while others can take years or never recover fully. 

“It can be a huge detriment to quality of life,” says Nicholas Riccardi, doctoral candidate in the Department of Psychology.

Riccardi is one of many researchers at the University of South Carolina working to understand how the brain works and what causes aphasia. He focuses on the brain’s semantic system. 

“Semantics refers to the meaning of words and concepts,” Riccardi says. “Hopefully, understanding better how language works in the brain can lead to different types of therapy."

Through his dissertation and work with psychology professor Rutvik Desai, who has been his mentor since he was an undergraduate at USC, Riccardi is learning more about which areas of the brain control aspects of language ability. 

To map the brain, Riccardi has research participants complete various tasks while scanning their brain activity. His experiments also use brain stimulation to disrupt their anterior temporal lobe. The folded section sitting along either side of the brain, this lobe is theoretically known as the “semantic hub” of the brain. 

“We’re trying to see if this disruption leads to impairments related to words and pinpoint areas we can target to disrupt certain language abilities,” Riccardi says. “This will help us learn if this specific area is as important to language as many scientists believe.” 

His aim is to map out the brain's important language areas and to learn how they connect to each other and how other areas of cognition contribute. 

“To understand the sentence 'I kicked the ball,' your brain might be actually using the perception and action areas of the brain – tapping into the thing you actually feel and see when you kick a ball,” Riccardi says. 

“If motor areas of the brain are impaired, does that make the person worse at understanding action-based language as opposed to other language that doesn’t involve action?”

Riccardi uses brain stimulation and functional MRI scans to measure brain activity fluctuations while the participant is doing tasks, like naming pictures or matching up similar objects.

“We theorize that disrupting the anterior temporal lobe is going to impair them in doing the tasks that use words as opposed to the tasks that don’t,” Riccardi says.

“This is important because there’s a form of dementia that attacks the anterior temporal lobe, and to better understand this disease, we need to understand what this area really does.”

The goal: clinical care 

USC recognized Riccardi’s work by naming him a 2023 Breakthrough Graduate Scholar. His interdisciplinary research could contribute to future breakthroughs in dementia and aphasia interventions. 

“Being able to provide better care for those with aphasia and dementia is the ultimate goal,” Riccardi says. 

His work so far has not been in a patient care setting, but after he finishes his doctoral degree this spring, Riccardi hopes to move toward more clinical work, like the research he’s seen in USC’s Center for the Study of Aphasia Recovery.

Led by Vice President for Research Julius Fridriksson and psychology professor Chris Rorden, C-STAR works with stroke survivors who experience aphasia. Riccardi has contributed to their research efforts and found mentors in Fridriksson and Rorden, who co-direct the McCausland Center for Brain Imaging. 

“There’s a lot of research going into brain stimulation and how, in conjunction with speech-language therapy, it may one day be able to help people with aphasia recover language ability," Riccardi says.

In studying the brain of someone who has had a stroke, future researchers may be able to see what areas of the brain have been damaged and try to encourage those areas to recover and, in other cases, to find and strengthen connections in the brain.

While this research is still in its infancy, Riccardi hopes that his own research about the “semantic hub” will fill in some of the gaps in understanding the brain.

“Every little bit matters in understanding the brain,” he says. “What we’re learning now may lay the groundwork for therapies and treatments in the future.”