“The better you understand the definitions of mild TBI, the better equipped you are to read the records, evaluate the experts, and keep your case grounded in sound medicine.” – Tom Crosley Welcome to Winning The TBI Case, hosted by trial lawyer Tom Crosley. Listen as Tom provides practical, powerful guidance for litigating traumatic brain injury cases. This podcast is meant for litigation attorneys who are ready to explore the essentials of TBI cases to confidently represent clients who have suffered traumatic brain injuries. What’s In This Episode:In this episode, Tom Crosley explains how mild traumatic brain injury is defined using both the ACRM 1993 and updated 2023 frameworks. He breaks down the three primary pathways to diagnosing TBI and how those definitions show up in real cases. And finally, Tom provides the simplified jury presentation that keeps the focus on symptoms, causation, and long-term impact. Understand the Framework This is for trial lawyers who want a clearer, more practical understanding of how mild TBI is defined and how those definitions are used in real cases. Tom Crosley breaks down the definitions that form the backbone of every brain injury case. He explains the evolution from the 1993 American Congress of Rehabilitation Medicine (ACRM) definition to the comprehensive 2023 update that created three distinct pathways to diagnosis: Clinical signs Symptoms with objective findings Abnormal imaging (NOTE: most mild TBIs will not appear on routine scans) If you’ve ever found yourself caught in a word play battle with the defense over terminology instead of focusing on the injury itself, this episode will help you reframe your approach. Winning the TBI Case — Episode 18: TBI Defined Crosley Law | Aired: April 2, 2026 | Runtime: 12:28 | Speakers: Narrator, Tom Crosley [0:00] Tom Crosley: The case is not about the label. The case is about what the symptoms are and were those symptoms caused by the crash or the event, and what does the future hold? [0:09] Narrator: TBI cases can feel like navigating uncharted territory. Your client’s injury is real, but proving it, that’s where the real challenge begins. If you’ve ever felt like you’re missing crucial pieces of the puzzle, you’re in the right place. Welcome to Winning the TBI Case, where Tom Crosley shares the insights he’s gained from over 60 injury trials. Not just the victories, but the lessons learned along the way that make all the difference. This is practical wisdom from someone who’s been in your shoes and found a path forward. Winning the TBI Case, strategy, science, and storytelling. Let’s join Tom as he breaks down the fundamental challenges of representing clients with invisible injuries. [1:00] Tom Crosley: Welcome back to Winning the TBI Case. I’m Tom Crosley, and today I want to talk about how mild traumatic brain injury gets defined, and this can become clunky in a hurry, and I don’t want it to turn into a word game instead of a useful discussion, so I’m gonna try to keep this simple and practical. Here’s the main point. Definitions matter, but they are not the whole case. A case does not rise or fall just because one expert wants to call it a mild TBI and another wants to call it something else. At the end of the day, the real questions are still the same. What happened in the traumatic event? What symptoms and impairments followed to your client as a result of that? Were those problems caused by the event? That’s where the case lives. How do these problems affect that person going forward in life? What does the future hold for this person? It’s not what label we attach to the injury. It was the injury caused by the event. So if a person develops headaches, dizziness, cognitive problems, balance trouble, light sensitivity, fatigue, irritability, an inability to function the way they used to function, those are always going to be real problems regardless of whether a defense expert wants to claim that it’s not a mild TBI. [2:21] Tom Crosley: So why then do definitions matter? They matter for two reasons. First, the better you understand the definitions of mild TBI, the better equipped you are to read the records, evaluate the experts, and keep your case grounded in sound medicine. The better able you are to avoid getting sidetracked by defense wordplay and semantic games. Second, medical literature is built on definitions. Researchers define who counts as a mild TBI and who does not, and then they study recovery, prognosis, treatment, long-term outcomes based on that defined group. So if you don’t understand the definition that they’re using, you probably don’t fully understand the literature either. So before I go further, let me say one quick word about the American Congress of Rehabilitation Medicine, the ACRM, because we’re studying and relying upon the ACRM definitions here. The ACRM is a major interdisciplinary rehab organization focused on research and evidence-based clinical practice. Its brain injury work has long been considered mainstream for over three decades. When the ACRM publishes something on TBI, lawyers should understand that this is important and widely respected. [3:43] Tom Crosley: It’s not some fringe view. So let’s talk about the 1993 ACRM definition of mild TBI, which for decades was the classic definition of mild TBI. It said that mild traumatic brain injury is a traumatically induced disruption of brain function shown by one of four things. Loss of consciousness, anywhere from zero minutes all the way up to 30 minutes. Beyond 30, it becomes moderate. Loss of memory around the event, so amnesia, as long as the amnesia resolves within 24 hours. If you have amnesia for more than a day after the event, they’re calling that moderate also. A fourth thing that will fit is focal neurologic deficits. It just means some kinda localized neurologic abnormality. Examples would include weakness or numbness on one side, facial droop, slurred speech, abnormal pupillary response, a visual field cut, impaired coordination in an arm or a leg. Those are pretty unusual, at least in my handling of these cases when I’m looking at medical records and we tend to see altered consciousness. Even if the person is not unconscious, we see altered mental status, dazed, confused, et cetera. Rarely do I see a documentation of a focal neurologic deficit, but it’s important to know what that means. [5:02] Tom Crosley: So the 1993 definition mattered because it gave medicine kind of a common agreement point. The problem is, over time, that got messy. Different specialties started using different approaches. Sports medicine came up with its own definition. Emergency medicine came up with another. The American Academy of Neurology came up with a different one. The neurosurgeons came up with a different one. So the ACRM got together leading up to 2023 and said, “Hey, we need to fix this and have one universal definition that we can all kinda rely on.” It was an effort to bring more order and consistency to the diagnosis of mild TBI. You probably ought to read it. It’s six criteria. It’s three different pathways, but it’s really easy to get lost there. So I try to boil it down, and if I’m gonna teach it to a jury, I’m gonna try to boil it down as basically as possible. That’s what I’m gonna try to do for you in this episode. I’ll leave it to you to let me know whether I succeeded or not. But here’s how I boil it down. Under the 2023 framework, there first has to be a plausible mechanism of injury, some kind of event capable of transmitting force to the brain. It could be a blow to the head. It could be the head striking an object. It could be acceleration, deceleration from a crash. [6:19] Tom Crosley: It could be a blast wave concussion type force. But once you have the plausible mechanism, there are basically three ways to get to the diagnosis. The first way is some obvious clinical signs. It’s the easiest one to understand. You have the injury event, and then you have obvious clinical signs of acute brain dysfunction. This route feels similar to the old 1993 definition. The second way of three that we get there without obvious clinical signs, we get there with symptoms plus objective support. So not every legitimate mild TBI comes with a nice clean witness account or a perfect ER note saying that the patient was definitely confused and repetitive at the scene. Real cases are often messier than that. Sometimes the person has the classic early symptoms, headache, dizziness, nausea, light sensitivity, brain fog, trouble concentrating, irritability. And sometimes those symptoms are backed up by objective findings on examination, such as abnormal balance, some kinda abnormal oculomotor testing, some kind of vestibular issue, an abnormal cognitive screen. So if you have some of those symptoms, two or more, and you have some kind of objective medical screen, then that is how you get there. [7:38] Tom Crosley: The third way you get there is abnormal structural imaging. That means a CT scan usually done in the ER, which as we know in these cases is most often normal. The other way we get there is a structural MRI that shows some kinda intracranial abnormality that’s related to trauma. That’s the imaging route. So let me be very clear here. Positive imaging is not required to diagnose a mild TBI. It has never been. Most mild TBIs do not show up on routine CT or MRI, but when they do show up on CT or structural MRI, that supports the diagnosis directly. And a lot of times, depending on what the abnormality is, it may move it beyond the mild realm into the moderate realm. I’m gonna leave advanced neuroimaging for another episode and keep today’s focus on the core diagnostic framework for the 2023 ACRM definition. That’s the simplified upd