Concussions can be pretty uncomfortable injuries. Your head hurts. Your body often hurts. Sometimes you’re very sensitive to light and sound. Often, people who have had a concussion feel “foggy” or “fuzzy” for the first few weeks, when they are aware that something about the way they’re thinking is just not quite right. As recommendations have begun to move away from strict cognitive rest during the period after concussion (avoiding any activity) toward one that’s more flexible (slowly rejoining activities over time, and taking breaks as needed), people’s experiences with these mild head injuries have begun to raise new questions about how the brain functions immediately after injury and how that impacts our ability to communicate effectively in that time.
Difficulty coming up with and saying the word you want to say is one way that we know adult communication can be impacted by a brain injury. Previously, this has been seen in people with severe, focal brain injuries, like strokes, and had been reported in a small sample of so-called “mild complicated” brain injuries in adults. These were people who had a somewhat mild TBI that was complicated by some factor, such as an atypically long period of amnesia or multiple previous injuries. This difficulty coming up with the word you want is called a “tip of the tongue” experience because you have the concept or idea in your mind, but the word just isn’t coming to you. It’s as if it were “on the tip of your tongue”. For me, this happens most often when I try to think of names of actors I’ve seen or authors of something I’ve read. For example, I know the lead actor in Titanic. I’ve seen that film so many times. I can picture him there hanging on to the floating door. I could even confidently tell you that the right actor I am thinking of is NOT George Clooney or Brad Pitt. But, sometimes coming up with that name (it’s Leonardo DiCaprio) is something my brain just won’t do (or worse, it comes to me 3 days later while I’m in the middle of cooking dinner). The important thing to remember is that everyone has tip of the tongue moments. However, when you’ve had a brain injury, the number of times those moments happen is even more frequent, and with words that are more common. So, whereas I might not be able to remember the name of the actor in Titanic on a normal day, after a concussion, I might not be able to remember the name of that fluffy white animal that we count when we’re trying to fall asleep.
As I said before, previous studies have found this effect in adults with this mild-complicated profile, but it seemed like the kind of thing someone feeling “fuzzy” after a concussion might experience, too. Moreover, most of the work that is done in concussion is done in young adults. This makes it hard to know quite how the developing language system is impacted by a mild brain injury in children, including whether the pattern of difficulties seen commonly in young adults is similar or different.
In the case of something like tip of the tongue, children in particular may not have the emotional maturity to realize that these deficits are not permanent, so a problem with remembering the right word can be extremely frustrating and embarrassing.
Given these observations, we decided to investigate a relatively straightforward question: Does a concussion give a young person, 10-20 years old, difficulty thinking of the word they want to say? We wanted to think of difficulty in two different ways that we thought might impact how a person actually performs in their day-to-day life: whether or not they accurately named a common picture correctly, and how long it took them to name that picture once they quickly saw it. In particular, we thought the question of how long it took them might give us more insight into the experience of “fuzziness.”
In order to test this, we asked each of 32 participants (with a mean age of just over 14 and a half) who were within 30 days of their first concussion, and 26 age-matched participants with no history of brain injury to name 107 different rapidly-presented pictures as quickly as they could into a specialized microphone that let us precisely measure when they began responding. These were simple, frequent, concrete words – the kinds of words that people should “just know,” like “strawberry” or “sheep.”
As a group, the people with concussion didn’t name the words less accurately than those without one. We hadn’t really expected them to, since these words are very frequent and the injuries are very mild, so we expected that this was a fairly easy task. However, what was particularly interesting was that the people with a recent concussion were significantly slower, around 300 milliseconds slower within the first week, and 200ms within the second. After that, differences in processing time were no longer significant. That may not sound like a lot of time in behavioral terms, but insofar as it reflects slowed processing in the brain, it’s a fairly substantial difference. Detection of a visual stimulus, for example, takes around 190 milliseconds for the brain. And, of course, this was with really simple words – we might expect even greater (and more noticeable) slowing when trying to access something that was already a bit harder to start with.
Another thing we found was that the types of errors made by individuals with concussion and those without were not notably different. This tells us that the system of semantic information storage is intact, as we would expect it to be, but accessing it is slowed.
So, what does slowed access really mean for people with concussion?
It’s hard to say. It seems plausible that this could explain some of the “fuzziness” people experience when they attempt difficult tasks or communicating with others after a recent injury. It may be more difficult to think of the right word on an essay test, or when writing an email during recovery. I think to some extent, this research touches another issue as well, that vaguely defined cognitive or communication deficits that people describe as a part of their lived experience after concussion are no less real despite the fact that paper-and-pencil testing may show performance within normal limits. While this may not make much of a difference in clinical management on its own, it is the kind of thing that matters to patients: that simple uses of language that seem more difficult, that feel more difficult through the fog, really have become just a little bit harder, and that, when we look at how the brain accomplishes the task of naming, not just whether or not someone eventually gets the right answer, we can see it, too.
For more information, check out our recent article: Stockbridge, M. D., Doran, A., King, K., & Newman, R. S. (2018). The effects of concussion on rapid picture naming in children. Brain injury, 32(4), 506-514. https://doi.org/10.1080/02699052.2018.1429660
Melissa Stockbridge is a candidate in the combined program for M.A. and Ph.D. in Speech-Language Pathology at the University of Maryland. Under the supervision of Dr. Rochelle Newman, her primary research interests focus on pediatric brain injury as it relates to linguistic, cognitive, and emotional individual differences and development. She has a M.Sc. in cognitive neuroscience from the University College London, Institute of Cognitive Neuroscience and a B.A. in applied linguistics from the University of Maryland Baltimore County, Honors College.