Quick answer
A prior concussion or medical condition does not by itself prevent a claim. Under the eggshell skull rule, a defendant must “take the victim as they find them” and can be liable for the full extent of an injury even if the person was more vulnerable than average.[1] The dispute is usually over which symptoms the new injury caused or worsened, which is why pre-injury records matter.
The eggshell skull rule
LII explains that under the eggshell skull rule, a defendant takes the victim as they find them, so a defendant is liable for the harm caused even if a pre-existing condition made the injury worse than it would have been for someone else.[1]
Prior concussions
NINDS notes that recovery tends to be slower after repeat concussions.[2] In a claim, a history of prior concussions can be raised by both sides: by the defense as an alternative explanation for symptoms, and by the injured person as a reason the new injury had a greater effect.
Aggravation of an existing condition
When a condition already existed, such as migraines, depression or anxiety, the question is usually whether and how much the injury made it worse. VA rules provide one example of how the law treats this: compensation is available for disabilities incurred or aggravated during service,[3] and certain conditions, including depression within set time limits, are presumed to result from a service-connected TBI.[4]
Records from before the injury
Pre-injury medical records show the person’s baseline: whether they had headaches before, how often, and whether they were being treated. The other side can generally request them because discovery covers nonprivileged matter relevant to a claim or defense.[5] Patients can get their own records under HIPAA.[6] See medical records.
Disclosure to treating providers
Frequently asked questions
Can I still have a claim if I had a concussion before?
Yes. Under the eggshell skull rule, the defendant takes the victim as they find them.[1] The claim focuses on what the new injury caused or worsened.
Can the other side get my old medical records?
Usually, if they are relevant. Discovery covers any nonprivileged matter relevant to a claim or defense and proportional to the needs of the case.[5]
This page provides general information about the law from the sources listed below. It is not legal advice, and reading it does not create an attorney-client relationship. Laws vary by state and change over time. See our legal disclaimer.
Sources
- Legal Information Institute, Wex. “Eggshell skull rule.” https://www.law.cornell.edu/wex/eggshell_skull_rule
- National Institute of Neurological Disorders and Stroke. “Traumatic Brain Injury (TBI).” https://www.ninds.nih.gov/health-information/disorders/traumatic-brain-injury-tbi
- U.S. Department of Veterans Affairs, Veterans Benefits Administration. “Compensation.” https://www.benefits.va.gov/compensation/
- 38 CFR § 3.310, Disabilities that are proximately due to, or aggravated by, service-connected disease or injury. Legal Information Institute. https://www.law.cornell.edu/cfr/text/38/3.310
- Federal Rules of Civil Procedure, Rule 26. Legal Information Institute. https://www.law.cornell.edu/rules/frcp/rule_26
- U.S. Department of Health and Human Services. “Individuals’ Right under HIPAA to Access their Health Information.” https://www.hhs.gov/hipaa/for-professionals/privacy/guidance/access/index.html
Sources last checked: October 11, 2026
