Hippocampus (Alzheimer's Disease)

Hippocampus: The hippocampus is involved in forming new memories, and helping you keep track of what is happening during your life!  In AD (Alzheimer’s disease) and Dementia, this memory system is often damaged early, which is why people can repeat questions, forget recent events, and feel lost even in familiar conversations.

Am I going to jail? He asked. 

He was sitting across from us in a worn rocking chair, at the assisted living home, his eyes locked on mine. My client, an elderly man with advanced Alzheimer’s, clutched the edge of his seat. We had traveled for one and a half hours, early in the morning to beat Boston traffic — to visit him since he couldn’t drive. Every five minutes, he repeated the question, one after the other, like he was suspecting his doom of incarceration. We had introduced ourselves as visiting from the Legal Services Center of Harvard Law School to help with his estate plan, but all he heard was legal services and attorney, and all he felt was fear. 

His name was on our intake sheet. His estate plan had been delayed. That was our official reason to visit him. But in the two hours we spent with him, he did not ask about wills or documents, despite us gently urging him to. Instead, he asked for his wife. She had died a month earlier, but he didn’t remember. He still called the hospital everyday, begging for her updates on her condition. Eventually, the staff had to take away his phone. Those two hours passed slowly and then all at once. We were told by his nephew to avoid the topic of his wife, so when he asked us where she was, we hesitated. I recalled one of the very important rules of working in law; to have the sole focus be your client. We said we weren’t sure, we didn’t know her, and that our focus was on his estate. And then we sat with him in that not-knowing. The legal questions we had came with—questions about distribution of assets, his old estate that is no longer valid—had chipped away. What remained was his confusion, his grief, his fragile mind.

For a long time, I couldn’t understand how someone could ask the same question again and again and truly not remember asking it. From the outside, it can look like stubbornness, or like the person is not listening, or like they are choosing not to accept reality. Neuroscience changed that for me. It helped me separate intent from brain function. The hippocampus is central for forming new episodic memories, meaning it helps record what just happened and what is happening right now so it can be recalled later. In Alzheimer’s disease, early pathology often affects medial temporal structures and spreads in predictable patterns, which can disrupt the ability to lay down new memories early on (Braak & Braak, 1991). That means you can answer a question carefully, and the answer can still fail to stick in the brain as a stable memory.

This also helps explain why emotion can remain even when facts disappear. For example, a person can retain a strong feeling like fear, confusion, or urgency even if they cannot remember the explanation that would resolve the fear. So the brain returns to the same question because it cannot update itself with the new information. It is like the conversation keeps resetting to the same starting point. Models of Alzheimer’s progression describe memory decline as a central early feature that reshapes daily functioning and the ability to use new information (Jack et al., 2010). Have you ever tried to reassure someone and realized you had to reassure them again five minutes later, not because they did not trust you, but because their brain could not hold the reassurance?

This makes the wife part even more painful. In Alzheimer’s, older memories can sometimes stay accessible longer than recent memories, especially early in the disease, because older memories are often stored and reinforced across broader networks over time. Newer events are more dependent on intact memory formation systems. So, he could still reach for the emotional structure of his life, while the recent reality of her death could not stabilize in his mind. That is why he called and begged for updates. This behavior, to him, was not irrational inside his brain’s version of time. His brain was living in a world, where she still might be somewhere else and might still need him.

When I learned this, the legal questions started to feel different. Legal work assumes stable comprehension, good memory, and consent. It assumes that a person can take in information during a meeting and hold it long enough to make a decision. Alzheimer’s undermines those assumptions, and that is why ethics is crucial. How do you protect someone without erasing them? How do you respect a person’s dignity when their brain cannot reliably carry the present? And how do you decide what capacity means when capacity can fluctuate even within one hour? These are not abstract questions when you are sitting across from someone whose fear is real even when their memory is not.

References:

Braak, H., & Braak, E. (1991). Neuropathological stageing of Alzheimer-related changes. Acta Neuropathologica, 82(4), 239–259. https://doi.org/10.1007/BF00308809

Jack, C. R., Jr., Knopman, D. S., Jagust, W. J., Shaw, L. M., Aisen, P. S., Weiner, M. W., Petersen, R. C., & Trojanowski, J. Q. (2010). Hypothetical model of dynamic biomarkers of the Alzheimer's pathological cascade. Lancet Neurology, 9(1), 119–128. https://doi.org/10.1016/S1474-4422(09)70299-6