March 10, 2020
It may come as a surprise that the Centers for Disease Control (CDC) estimates there are more than three million concussions each year in the United States alone. Concussion, or mild traumatic brain injury (mTBI), is commonly caused by accidents, falls, car crashes, and other traumas. It refers to a hit to the head that causes the brain to bounce back and forth within the skull. At the neural level the jolt causes the neurons to stretch, with some of them stretching to the point of breaking.
Diagnosis of concussion is through clinical interaction, as there is no reliable lab test or accurate imaging protocol that can detect concussion. Loss-of-consciousness is not required for a concussion diagnosis, although it does often occur. The physical symptoms associated with concussion include headache, sleep disruption, brain fog, attention and memory difficulties, and greater emotionality. After a few days of rest, symptoms tend to subside and people are expected to slowly return to normal activities. The expectation is that within a few months all symptoms and cognitive effects will return to normal. However, new findings suggest that maybe recovery does not mean pre-injury ability.
Recent research in my Memory and Brain Lab has asked whether there may be lasting consequences of concussion. My research team, with work lead by graduate student Hector Arciniega, and long-term undergraduate research assistant Alexandrea Kilgore-Gomez, is asking this question because many of our students report having experienced head injury from skiing, horseback riding, bike accidents, and life in general.
Over the last few years we have tested more than 225 undergraduates with a history of concussion over their lifetime. Students come to the lab and complete computer tasks asking them to remember a few items for a brief amount of time. For example, participants might see one to three colored squares briefly flashed. Then, after a brief delay they would be asked to report whether one test square changed its hue or not.
Despite the fact that the undergraduates average more than four years since their concussion, they do not perform as well as their peers who have never had a concussion. We see general performance impairments in the concussion group when we test them on many kinds of visual working memory and visual attention tasks.
It is troubling to see that performance deficits emerge when participants are asked to hold onto three things for only .5 seconds. This pattern of impairment so long after concussion is particularly troubling for undergraduates because working memory is needed for problem solving, manipulating information, and even reading. All of these tasks may make being an undergraduate even harder for these students.
This semester, undergraduate students Joseph Castellanos and Olivia Hall are beginning research to determine whether students with a history of concussion are more likely to change majors or classes, or whether they need to study more, or in more quiet areas. We suspect lasting effects might be even worse in the general population.
Our current work is understanding the neural changes associated with behavior differences. Our long-term goal is to develop interventions that improve performance in students with a history of concussion. This work is supported in part by generous funding from the Tahoe Institute for Rural Health Research.
Prevention of head injury is important. Please remember to always wear your helmet while skiing and biking, to childproof your home effectively, and to place reflective tape on stairs to avoid falls in older adults’ homes.