Mild enough to avoid detection by any medical testing used in a clinical setting but severe enough to preclude the plaintiff from ever enjoying a productive and meaningful life again. This is the most common fact pattern in the mild traumatic brain injury (mTBI) cases that we receive calls on these days. The force of impact is often minor. We have seen mTBI claims born out of 8 mph rear-end collisions where the damage to the plaintiff’s vehicle was only $500-$1,000 but the damage to the plaintiff, according to their attorneys, was in excess of $30M. Often, the plaintiff does not receive immediate medical attention so there are no MRIs or CTs to prove a traumatic injury is present and if there are, they usually show no evidence of injury. Instead, they visit a primary care provider months later, self-reporting symptoms they attribute to the incident. Their doctor, relying on this self-report, notes in the medical record that the plaintiff suffered a concussion or TBI as a result of the incident at hand, which then gets repeated by reference across dozens of subsequent medical records even though no medical testing was ever performed to verify this conclusion. And of course, the doctor typically uses a medical term like “brain injury” in the records, which the average juror perceives as more dramatic and harmful than it might be.
Lacking any objective evidence of a brain injury, plaintiff attorneys hire one of a small number of medical experts who rely on “experimental” techniques to prove the existence of the brain injury, such as Diffusion Tensor Imaging (DTI). However, “experimental” is often just the clever descriptor used to disguise the fact that the technique is not FDA-approved, not used in a clinical setting, and has largely been shown in the academic literature to be unreliable for reaching the conclusions they purport to reach. Yet jurors find it persuasive because the expert can point to something in a picture and convincingly tell jurors that spot in question is abnormal. Jurors, by and large, love this type of evidence.
Confident in the lack of objective evidence to support the plaintiff’s claims, the defendant marches forward to trial, only to get hit with a large verdict. The result feels inexplicable. Surely, proclamations of jurors gone crazy will follow. How could jurors have arrived at such a verdict with such little evidence to support the plaintiff’s claims? How could a 10 mph rear-end collision that left little visual evidence of damage to either vehicle result in such a preposterous verdict? In this article, we attempt to explain the factors that drive verdicts in mTBI cases. Specifically, we draw on our experience in over 30 recent mock trials across the country in cases involving mTBI claims and data from independent studies we have conducted to better understand how jurors evaluate mTBI claims. We start by showing how and why plaintiffs often prevail in these cases and then highlight effective strategies for defending against these claims.
Let’s start with one of the simplest reasons plaintiffs gain ground with jurors in mTBI cases, which is that any reasonable doctor will readily admit that an individual can suffer from a life-changing concussion with little objective medical evidence to prove it. Any reasonable doctor will agree that concussions do not always show up on MRIs or CTs, that an individual can seem fine immediately after an incident only to get significantly worse weeks or months later, and that even the mildest of concussions can have a life-changing and debilitating impact on an individual, even in the face of no medical evidence to prove it. When defense experts make these admissions in cross-examination, the impact can be significant. In an odd way, the lack of evidence, paired with these admissions, actually becomes evidence itself for the plaintiff’s claims. It is frustrating but defense attorneys should not underestimate the persuasive impact of these admissions from their highly-paid medical experts.
How can this seemingly low level of proof equate to a preponderance of the evidence? Defense attorneys can refer back the first tenet of jury economics that jury decision-making is egocentric. Jurors filter the facts and evidence through their personal experiences to determine what is true and what is false. This is important because one of the emerging phenomena among Americans over the past decade or so is the difficult-to-diagnose health condition. A rising number of Americans are dealing with health conditions that do not show up on traditional medical tests. Autoimmune disorders and inflammatory diseases are common culprits. Many have experienced the frustration of knowing and feeling that something is wrong, but doctors are unable to identify the cause or the condition. The result is that the concept of a debilitating medical condition that does not show up on traditional medical tests is becoming ubiquitous among jurors, making it easier to believe when a plaintiff in an mTBI case makes such a claim. In our mock jury deliberations, we often see someone who has suffered from such a condition become an outspoken advocate for the plaintiff, which is why it is so important for defendants to identify and “de-select” these individuals during jury selection.
It is also important to recognize the impact of medical records, even when they are largely based on self-report. Jurors do not necessarily discount medical records because they rely on self-report, especially when language such as “brain injury” is repeated throughout the records. It often begins with self-report to one doctor and then gets repeated as other providers reference the original self-report. The result is dozens of references to a “brain injury” that jurors are often unwilling to explain away as mere conjecture. Maybe they will do it for one or two references, but not for this many. Consequently, while it is easy for defense attorneys to downplay these instances of self-report, they can be incredibly impactful to jurors.
Then there are the experts and their “experimental” techniques. Anyone who tries mTBI cases knows the reality of these experimental techniques, but jurors do not. DTI is the most popular used by plaintiff advocates. For jurors, the moment an expert puts a brain image on a screen and points to a highlighted area, the discussion often ends. The expert does not need to overwhelm the jury with complex science. Instead, they simply need to give jurors permission to believe that what they are seeing is abnormal. Because jurors have no frame of reference for what a “normal” brain scan should look like, almost anything can appear concerning when it is isolated, enlarged, color-coded, or compared to an abstract statistical baseline.
This dynamic is particularly powerful because brain scans carry an inherent aura of objectivity. Jurors may not understand how the image was generated, what assumptions went into the analysis, or how often similar “abnormalities” appear in healthy individuals, but they do not need to. The expert’s ability to point to something—a shaded region, a cluster of pixels, a deviation from a color scale—creates the impression of concrete proof. When jurors are shown a picture and told, “This is not how it’s supposed to look,” they have no practical way to challenge that assertion. Most jurors instinctively assume that if an expert can identify a specific location in the brain and label it as damaged, then the injury must be real.
What makes this even more persuasive is how little effort it takes to generate doubt in the defense position. Defense attorneys can explain that the technique is experimental, not FDA-approved, or not used clinically, but those arguments often feel simultaneously technical and abstract compared to the visual certainty of an image on a screen. Jurors may not understand why a method is unreliable, but they understand what it feels like to see something that looks wrong. When you do not know what you are looking at, the mere existence of a highlighted “abnormality” can feel like credible evidence.
Compounding this dynamic is the dramatic shift in how our culture understands concussions. Over the past decade, concussions have been thrust into the national spotlight, largely because of the NFL. As the most popular sport in the United States, the NFL has played a central role in reshaping public perception—not just by acknowledging the risks of head injuries, but by repeatedly reinforcing the message that our prior understanding of concussions was dangerously incomplete. Stories of former players suffering from long-term cognitive decline, depression, and chronic traumatic encephalopathy have become part of the cultural consciousness. The takeaway for the average juror is simple: concussions are serious, invisible, and often underestimated.
This cultural backdrop heavily favors plaintiffs in mTBI cases. Jurors walk into the courtroom primed to believe that concussions can be life-altering, even when they do not show up on traditional medical tests. More importantly, they are primed to distrust arguments that minimize concussion severity. When defense experts emphasize the absence of objective findings or downplay the mechanism of injury, those arguments can sound outdated, echoes of a time before we “knew better.” In the jurors’ minds, this is not just a disagreement between experts—it is a clash between modern understanding and old thinking. Against that backdrop, it becomes much easier for jurors to side with the plaintiff and conclude that the science will eventually catch up to what the plaintiff is experiencing now.
So where do defendants go in the face of these challenges? First and most important is the second tenet of jury economics, which is to refocus on the reality that jurors engage in economical decision-making. They are looking for the easiest and simplest route to understanding the injuries. This is important because too often defense counsel tries to rebut (m)TBI claims with complex medical and scientific evidence that does not survive many of the one-liner kind of arguments or simplifications that tend to favor plaintiffs. Jurors want something simple. For example, they often judge whether a plaintiff suffered a brain injury by assessing whether the collision seems likes something that could cause a brain injury as severe as they claim. The more violent the collision, the easier it is to believe the plaintiff must have suffered a brain injury. We have found that there are a variety of compelling shortcuts defendants can offer jurors to simplify the way they think about the plaintiff’s mTBI claims.
First and most important, it is important for defendants to not let an mTBI claim overshadow the other injuries claimed by the plaintiff. It is not unusual in our experience for a plaintiff to also claim back and/or other musculoskeletal injuries that lead to life-long, debilitating and chronic pain. mTBI claims can often steal defense attorneys’ focus because of the exorbitant lifecare plans that come with these claims. But we have seen jurors award large numbers for simpler injuries such as chronic pain in these cases, especially in the face of uncertainty over the extent of the plaintiff’s brain injury. In one recent mock trial, we witnessed a jury conclude the plaintiff did not suffer a brain injury but still award millions for the chronic back pain they thought he would live with for the rest of his life.
Next, defendants should focus on the practical reality of the plaintiff’s life. Jurors may not understand the brain science at all, but they feel they can judge with their eyes whether the plaintiff is capable of living a reasonably normal and meaningful life. Consequently, simple evidence of the plaintiff’s ability to live a normal life often trumps abstract scientific evidence to the contrary. DTI scans become less persuasive against surveillance video of the plaintiff living doing things he or she claims they are no longer able to enjoy. Of course, a plaintiff attorney will naturally respond with the “good days and bad days” explanation, but the defense can highlight how the captured activity falls well outside
the kind of “good day” one would expect with the plaintiff’s brain injury.
Surveillance video is not the only way to accomplish this. In one recent mTBI case, the defense discovered the plaintiff regularly played online chess and was able to access the plaintiff’s online game history to show the chess scores remained the same before and after the incident, which the jurors found persuasive since chess is often used in studies to measure cognitive capacity.
This also highlights another effective strategy. When the defense catches the plaintiff in moments of dishonesty, these can be very impactful to jurors especially if the defense is able to show a pattern of dishonesty by the plaintiff. Dishonesty flips the script and the lack of medical evidence suddenly becomes proof there is no brain injury.
Regardless of the evidence of the practical reality of the plaintiff’s life, there will still be plenty of medical experts, and attorneys should take a page out of medical malpractice cases where so much of the case boils down to the likability of the defendant doctor. Jurors implicitly ask themselves in those cases, “Would I want this doctor caring for me and my loved ones?” If the answer is yes, the defense will do well. If not, things will not go well for the defendant. Consequently, the defense should look for medical experts who are likable, engaging, and leave jurors with the impression that they are the type of medical professionals jurors would want caring for their loved ones. Jurors are more likely to believe the testimony and conclusions of these expert witnesses and use likability as a shortcut when they do not fully understand the medicine.
In addition to being likable, the experts need to be repeatable, meaning jurors need to be able to re-articulate their opinions in the deliberation room. If jurors are not able or do not have the confidence to rearticulate these opinions, they will have little effect in deliberations and the opinions will fall by the wayside. Consequently, it is critical that defense experts frame their opinions in simple, memorable, and repeatable terms, ideally aided by compelling demonstratives that can be marked as exhibits and sent back to the deliberation room.
Additionally, when it comes to the medical experts, jurors often defer to treating doctors who they see as the most neutral and objective, especially if that doctor is from a local and reputable hospital. Jurors want to know what the doctors who actually cared for the plaintiff say outside context of the lawsuit. This testimony carries a lot of weight in the deliberation room so it is important for the defense to score its points with them, though defense attorneys should be cautioned against aggressive attacks on treating doctors since jurors see them as not having a dog in the fight. An aggressive attack of a likable doctor can backfire in significant ways.
Finally, thematic framing of the plaintiff’s alleged mTBI can be effective as well. For example, we often advise defense attorneys to contrast how it is only a mild traumatic brain injury when it comes to the plaintiff having to explain away the lack of objective evidence to support the brain injury claim, but suddenly becomes a severe, life-changing brain injury when it comes to damages. It can be effective for the defense to advance this theme and highlight how the plaintiff is trying to have it both ways. While plaintiff experts will argue (and defense experts will have to admit) that mTBIs can have severe consequences, it can be persuasive to jurors to highlight the kind of progression one would reasonably expect with an mTBI and contrast it to the implied progression in the plaintiff’s claim. For example, some jurors find it very difficult to believe a plaintiff can go from seeming fine the day of and in the days following the incident only to struggle with basic life functions months later. This means the defense can acknowledge that mTBIs can get worse in the days that follow an incident but argue that extreme progressions from one end of the spectrum to the other are highly unlikely.
Thomas M. O’Toole, Ph.D. is President of Sound Jury Consulting in Seattle, WA. Kevin R. Boully, Ph.D. is Senior Consultant at Perkins Coie in Denver, CO.
