A concussion is a type of mild traumatic brain injury that happens when a bump, blow, or jolt makes the brain move quickly inside the skull. Even though some people recover well from a single concussion, repeated concussions over time can contribute to lasting problems with memory and thinking.
Doctors and researchers have seen that people who have had many concussions often report trouble remembering recent events, following conversations, or learning new information. Clinics that treat concussion patients describe common issues such as short term memory loss, difficulty recalling names, misplacing objects, and feeling “foggy” when trying to think or concentrate, especially after multiple injuries to the head. You can find descriptions of these problems on clinical sites like Cognitive FX, which explains that concussions can cause memory loss and ongoing difficulties with both short and long term memory, focus, and mental clarity.[4]
Scientific and medical organizations are increasingly concerned about what happens when concussions keep happening again and again. The Medical University of South Carolina, for example, reports that repeated concussions can raise the risk of mood problems, memory loss, movement difficulties, and long term brain diseases such as chronic traumatic encephalopathy, often called CTE.[1] Their researchers created a laboratory model of repeated concussions and found that ongoing inflammation in the brain can damage the connections between brain cells. When those connections are harmed, it becomes harder for brain circuits to work properly, which may show up as problems with thinking and memory.[1] You can read more about this work at the Medical University of South Carolina: https://www.musc.edu/content-hub/News/2026/01/02/traumatic-brain-injury[1]
Memory decline from repeated head injuries is not only seen in athletes. Studies of survivors of domestic violence have found similar patterns. People who are exposed to repeated blows to the head or strangulation can develop traumatic brain injuries that lead to long lasting memory problems and other thinking difficulties.[3] Reports in outlets such as NR Times highlight that brain injuries in this context are often under recognized, but they can still cause significant memory loss and cognitive changes over time.[3] More details are discussed here: https://nrtimes.co.uk/research-links-domestic-violence-to-brain-injuries-seen-in-pro-sport-hnc25/[3]
Large studies of former professional athletes add more evidence that frequent concussions are linked to later memory decline. Alzheimer’s Research UK summarizes an 18 year study that followed hundreds of former American football players over the age of 50. Nearly one in four of these players reported early signs of memory loss, and almost one in ten had already been diagnosed with dementia, both rates higher than in the general population.[2] The highest risk was found in players who reported ten or more concussions during their careers.[2] The same position statement notes that rugby players with a history of repeated head impacts are also more likely to develop neurodegenerative disease than people who did not play at that level.[2] More information is available from Alzheimer’s Research UK: https://www.alzheimersresearchuk.org/about-us/our-influence/policy-work/position-statements/sport-and-dementia/[2]
Researchers are still working to understand exactly how repeated concussions lead to memory decline. One theory involves inflammation and the brain’s own immune cells. After a concussion, immune cells in the brain help clean up damaged tissue. However, the Medical University of South Carolina team has found that when this response becomes overactive after many injuries, these cells may begin to damage fragile but still living brain cells and the connections between them.[1] This “over cleaning” could slowly erode the networks needed for memory, attention, and clear thinking.[1]
Another line of research focuses on how head injuries might raise the risk of diseases such as Alzheimer’s. A report discussed by Legal Reader describes work from the University of Virginia, where scientists found that head injuries may interfere with the brain’s drainage system.[5] When this system is disrupted, waste proteins and other substances may build up in the brain, which could make it more likely that harmful proteins related to Alzheimer’s disease collect over many years.[5] The article explains that this type of damage can increase later Alzheimer’s risk after head trauma: https://www.legalreader.com/head-injury-linked-to-alzheimers-risk/[5]
Because dementia involves serious decline in memory, thinking, and daily functioning, the possible link between repeated concussions and dementia is a major concern. Alzheimer’s Research UK notes that people who have had a traumatic brain injury are about one and a half times more likely to develop dementia compared with those who have never had such an injury.[2] One unusual form of dementia, chronic traumatic encephalopathy, has been linked specifically to repeated head impacts and has been identified in some former professional athletes.[2] Researchers in the United Kingdom are now studying tiny particles released from brain cells after head impacts in American football players to see whether they spread harmful proteins and trigger inflammation that might contribute to dementia.[2]
For individuals who have had multiple concussions, memory problems can appear in daily life in many ways. People may forget appointments, struggle to remember recent conversations, or find that learning new work tasks takes much more effort than before. They might need to rely on notes, alarms, and other reminders just to stay organized. Clinics that specialize in concussion rehabilitation emphasize that these symptoms can be very real and distressing, even when brain scans look normal.[4] Rehabilitation strategies often focus on cognitive exercises, compensating tools like planners and phone reminders, and managing fatigue so that the brain has the best chance to recover.
It is important to remember that not everyone with repeated concussions will develop severe memory decline or dementia. Many factors play a role, including the number of injuries, how close together they occur, how quickly and carefully each one is treated, and a person’s age and general health. Still, the pattern seen across contact sports, domestic violence survivors, military personnel, and other groups exposed to frequent head trauma suggests that repeated concussions can significantly raise the risk of long term memory problems and possibly dementia in some people.[1][2][3][4][5]
If someone has a history of multiple concussions and notices increasing memory loss, confusion, or changes in personality, it is important to seek medical care. A doctor, preferably one familiar with brain injuries or neurology, can perform cognitive tests, review the history of head impacts, and recommend further evaluation if needed. Early recognition and support may help reduce the impact of symptoms and improve quality of life. It can also guide decisions about whether to avoid activities that put the head at risk for more injuries.
In everyday life, simple steps can help protect memory after a concussion. These include getting enough sleep, pacing mental and physical activity, avoiding alcohol or other substances that can affect the brain, using tools like calendars and reminder apps, and following the treatment plan given by healthcare providers. For people in high risk environments such as contact sports or unsafe relationships, reducing the chances of further head trauma is especially important. Sporting bodies and policymakers are increasingly urged to adjust rules, improve protective equipment, and strengthen education about concussion to better safeguard long term brain health.[1][2][3]