The debate showing Tuesday by John Fetterman, the Democratic candidate for Senate in Pennsylvania, has reignited questions about his recovery from a severe stroke in May.
In addition to highlighting the stark differences on policy between Fetterman and his Republican opponent, Mehmet Oz, the event also revealed the lingering effects of Fetterman’s stroke, which has noticeably impacted difficulties in processing auditory information. He used a closed captioning system as an aid but still did not always express himself clearly, mispronouncing or missing words and struggling to finish thoughts within time restrictions.
Such difficulties are common after strokes, which can damage certain brain areas by starving cells of oxygen. Yet symptoms can improve, or completely resolve, within months or years as the immediate damage heals and the brain finds ways of working around the affected areas.
Whether someone will make a full recovery, and how quickly, is difficult to predict. Democratic Sen. Ben Ray Luján from New Mexico also suffered a stroke in January but has had a smoother path to recovery than Fetterman.
Grid spoke with Brenda Rapp, a cognition scientist at Johns Hopkins University who studies how strokes impact language systems in the brain, about the wide spectrum of symptoms strokes can cause, how people recover, and the role technology, like closed captioning, plays in helping people retain their ability to function.
This interview has been edited for length and clarity.
Grid: What’s going on in the brain during a stroke? How does it impact brain cells?
Brenda Rapp: Neurons need oxygen and other nutrients to function, and that’s carried to them through the bloodstream. Strokes can interrupt this blood flow, which can lead to cell death of neurons that are downstream of where the disruption happens.
And so depending on where in the brain this happens, which cells are downstream of the blockage or the bleed, that determines what kinds of impairments someone would experience.
G: How can a stroke impact someone’s ability to process language? How wide-ranging can these effects be?
BR: That depends on where in the brain the stroke happens. We have a right and a left hemisphere of the brain, but they don’t do the same things, so different subregions of each of the hemispheres seem to be specialized. In most people, language is highly lateralized, meaning it’s controlled by one half of the brain, in this case the left. But language is a very big [concept] and has lots of very complicated machinery with lots of parts — involving spoken language, written language, language comprehension and language production.
As I’m speaking and you’re listening and understanding, all the machinery that’s involved in my speaking is different than what’s involved in your understanding speech. So those are all different parts of this left hemisphere machine, and when any of these get disrupted, we call that aphasia.
Depending on what blood vessels have been affected in a stroke, you might get some disruption to the understanding-of-speech part of the brain but not to the producing-speech part. You could have a mild speaking deficit or a more severe speaking deficit, or you might be unable to say anything at all. Understanding language and producing language are handled by different brain areas. Depending on how those brain areas are impacted by stroke, you can have more or less severe symptoms. But just because you have problems with one aspect of language doesn’t mean that you’ll have difficulty with all aspects of language.
G: I know you can’t speak directly to Fetterman’s specific situation, but are auditory processing issues like his relatively common?
BR: Deficits in understanding language or finding words are pretty common. Some parts of the language system are affected more commonly than others, which has to do with the vasculature of the brain, like where the blood vessels run through it, and lots of blood vessels run through areas that support language comprehension.
Word-finding difficulty is perhaps the most common thing that one sees in a stroke that affects the language system. We all experience this, like forgetting a name that comes to us five minutes later or not being able to think of the word for a thing we know, but that can become extremely exaggerated as a result of a stroke.
G: How do impairments like these, in information processing, relate to cognition?
BR: Aphasia is a language deficit, not a deficit of intellect. If you only have aphasia, then you don’t have difficulties in reasoning or thinking, remembering about your life. That’s because general cognitive processes are handled by different areas of the brain separate from what supports language-processing.
I’ve worked with so many people with aphasia whose thinking is perfectly clear. But it’s hard to always see that from the outside. When you see someone struggling to explain something that doesn’t seem like it should be that difficult to explain, you think, “Wow, this person is not thinking clearly because they’re not speaking clearly.” And we typically judge how clearly someone is thinking by how clearly they’re speaking, but that definitely does not follow. Just because someone is not speaking clearly, it does not follow that they’re not thinking clearly.
G: People can clearly recover from strokes, but that recovery isn’t always quick or complete. What do scientists know about how people recover from strokes and what’s going on in the brain while this happens?
BR: Well mostly, there’s just vast amounts that we don’t know, and it’s hard to know how well someone is going to recover. But there are a few things we think we know.
So, initially with a stroke, there’s this disruption of the blood flow that creates local, biological changes in that area, things like inflammation and fluid that’s released. That can create the pressure on adjacent tissues, causing them to not function normally. Once that pressure is relieved and the basic injury-related processes are resolved, which tends to happen in the first few months after stroke, performance improves, often dramatically.
That’s the first phase. After that has settled down, the brain tries to find alternative routes around roadblocks caused by the stroke, the tissue where there’s been cell death. There’s a lot of redundancy in the brain, so the brain tries to recruit that redundancy and reorganize itself, finding new ways to solve cognitive functions that have been disrupted. That process starts in earnest after a few months, after these basic biological processes have resolved, and that honestly can continue for 15, 20 years. It’s often most dramatic in the first two years after the stroke.
G: How does that second phase happen?
BR: That process of reorganization and recruiting redundancy in the brain, some of that happens naturally, just walking around in life and telling your brain “I want to understand this,” or “I need to speak,” it can find a way to do this. But it’s also facilitated through speech and language therapy. Which can really kind of push the brain to find new ways of solving these problems.
G: What role do tools like the closed captioning Fetterman has used in interviews and debates play in recovery?
BR: Yeah, they are wonderful and incredibly useful. As someone who works on this, [Fetterman’s experience] is a wonderful education that helps people see that technology can be really helpful in getting around these problems, whether it’s just a short-term thing during recovery or more long-term.
If you are having trouble processing words when people say them to you, but your reading system is just fine, then if you can just get those spoken words into the written form, then you’re fine. For us to have the technology to be able to do that in real time is just fantastic and makes it possible for someone to function very smoothly.
G: With all the discussion around Fetterman’s health after his stroke, what do you think is getting missed, or would like to emphasize?
BR: It’s just really worth emphasizing that strokes — especially strokes that affect just the language system — don’t change the person. Having aphasia doesn’t change who you are, what you believe, your values or your ability to think. You really are the same person. It can be difficult to express that, and it can be difficult for the people listening to you to be sure. It’s like, “Oh, they sound so different, have they changed in some fundamental way?”
We judge people so much by what they’re able to say, which is not surprising, it’s how we relate to each other. But there is a danger in overinterpreting that and not realizing that difficulties with language don’t represent changes in cognition or personality.
Thanks to Lillian Barkley for copy editing this article.