Is higher hippocampal brain activity linked to worse memory in dementia?

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.