When people with early memory problems have more random brain activity in the area that handles memory, their memory and thinking skills tend to get worse—not better. This might mean their brain is working extra hard to try to make up for damage, not that it’s getting stronger.

We analyzed the available evidence and found that higher hippocampal brain activity in people with early memory problems is linked to worse memory and thinking skills over time. This pattern was seen across all 48 studies or assertions reviewed, with none showing the opposite. The hippocampus is a part of the brain that helps form and store memories. When it’s damaged—like in early dementia—it may try to compensate by becoming more active. But this extra activity doesn’t seem to help. Instead, it appears to be a sign that the brain is struggling to keep up with damage, not that it’s getting stronger. Think of it like a car engine revving loudly because it’s failing, not because it’s performing better. What we’ve found so far suggests that this increased activity isn’t a sign of recovery or resilience. Rather, it may reflect the brain’s attempt to maintain function as its circuits break down. This doesn’t mean the activity itself causes memory loss, but it does appear to go hand-in-hand with it. We don’t yet know why this happens or whether it’s the same in all types of dementia. The evidence we’ve reviewed doesn’t explain if this pattern changes as the condition progresses, or if it applies to everyone with early memory issues. For now, if someone is noticing early memory problems and their brain shows higher activity in the memory center, it may signal that the brain is under stress—not that it’s fighting back successfully. This doesn’t change what you can do, but it helps explain why some people decline faster than others—even if they seem to be trying harder mentally.