Finding the Right Words

Kristen Carlstedt was just 31 years old when she suffered a stroke in 2008. Working as a physical therapist in Michigan, engaged to be married — Carlstedt lost everything, including her ability to communicate.

“I couldn’t talk for two weeks. Nothing,” says Carlstedt, who now speaks in short, deliberate sentences. “My first word was ‘guacamole.’ ”

Carlstedt moved home to Crystal Lake, Ill., and has been “starting over” ever since.

She was familiar with aphasia from her work as a physical therapist, but most people have never heard of the condition, a devastating disorder that essentially robs the brain of language. Caused in most cases by stroke or traumatic brain injury (Gabby Giffords, for example), aphasia affects more than 1 million Americans, with 80,000 new cases each year.

“The interesting thing about aphasia is it doesn’t affect any other cognitive systems,” says Northwestern professor Cynthia Thompson, one of the leading experts on aphasia. “These people are intelligent. They’re not impaired, except for when they need to use language, either reading, writing, talking or listening.”

Not long ago, stroke sufferers who lost the ability to talk were thought to have less than a year to recover language function. In her three decades of research, Thompson has demonstrated the brain’s plasticity and shown that, with appropriate training, gains can be made a decade or more after a stroke.

For more than three years Carlstedt has traveled to Northwestern twice a week to take part in therapy-based treatment studies at Thompson’s lab. She’s slowly regained some of her ability to speak.

Thompson, the Ralph and Jean Sundin Professor of Communication Sciences, is heading a new research venture designed to help aphasia sufferers like Carlstedt. Thompson is the principal investigator of the $12 million National Institutes of Health–funded Center for the Neurobiology of Language Recovery, headquartered at Northwestern. She’ll lead a collaboration of researchers from Johns Hopkins, Harvard and Boston universities to find biomarkers that can predict language recovery.

Researchers in Baltimore, Boston and Chicago will use functional MRI and other brain imaging techniques to study the role in language recovery of cerebral blood flow, resting state-brain activity and the integrity of white matter tracks in cortical tissue. The data from all three locations will be analyzed at Northwestern by Todd Parrish, associate professor of radiology, and his team at the Feinberg School of Medicine. The resulting database will be accessible to researchers nationwide.

The research will also shed light on neuroplasticity — the brain has an amazing ability to reorganize itself and regain lost function. Thompson has found that language training following stroke can increase activity in areas of the brain associated with language and related tasks, and people who benefit from treatment show evidence of neural reorganization. 

“The first step is to understand what regions of the brain are most likely to be recruited into the language network once it is damaged,” she says. “We want to know more about how the brain responds to focused treatment and how we can we push the brain to maximize the recovery.”

Thompson and her Northwestern colleagues will also look at eye tracking, comparing eye movement patterns of healthy people with those of people with aphasia.

“Looking at the eyes is sort of a window into the mind,” she says. “I study sentence processing. We record eye movements while people are listening to or producing sentences. And this reveals to us their cognitive processing ability.

“The ultimate goal is to be able to predict who might recover better than others and what kinds of treatment would be the best. We don’t want to paint a picture that’s incorrect. People do still continue to have language problems, but their functional communication can improve.”

Research conducted at the center will have the potential to challenge existing clinical practices for aphasia and promote the availability of treatment for individuals with chronic aphasia. 

The new center launched in April. Thompson and her colleagues are now looking for adults with aphasia to be part of the treatment studies. For more infor­mation, email CNLR@northwestern.edu or visit the Aphasia and Neurolinguistics Research Laboratory website.