I keep thinking about Alzheimer's

My earliest memory is the letter A.

I was in kindergarten learning how to write it, and the page had a picture of an ant. I don't remember what the classroom looked like. I don't remember who was sitting next to me, what I was wearing, what happened before the worksheet was handed to me, or what happened when I finished it. I just remember the A and the ant.

At least, I think I do.

That's the strange thing about trying to locate the beginning of your own memory. There is no clear beginning. I can't flip through my childhood chronologically the way I can scroll through photographs on my phone. There are pieces. Some memories are vivid, others are barely there, and entire periods of my life feel strangely empty. My family will tell me something I did and sometimes it suddenly clicks, as though they have handed my brain the missing piece. Other times, everybody remembers except me. I believe them because why would all of them collectively invent a childhood event that apparently only I forgot?

I sometimes say that I have a good memory, and I think I do, but what I really mean is that I have a good memory for the more recent version of my life. The farther backward I go, the less reliable the story becomes. There are photographs of me experiencing days I cannot remember experiencing. People I love can tell stories about a version of me I have absolutely no access to.

Which means I have already forgotten a huge portion of my own life. And somehow, I still feel completely like myself.

That bothers me because I tend to think of memory as something that sticks with you. I don't know where I imagine it sticking. Somewhere in the brain, obviously, but until I really think about it, memory feels almost like a collection of little files. This happened. Save. That happened. Save. Something important happened. Save forever.

The brain is considerably messier than that.

There isn't one little memory drawer inside the skull. Memory is really an umbrella term for several different processes involving different, although interconnected, parts of the brain. The hippocampus, a structure tucked deep inside the temporal lobe, is especially important for forming new declarative memories, the kind we can consciously recall and describe. Other brain systems help us retain skills and habits, attach emotion to experiences, recognize familiarity, and learn associations. This is why someone can lose one kind of memory while another remains surprisingly intact.

And remembering isn't exactly like pressing play on a recording. The brain reconstructs. When we retrieve a memory, we rebuild it from information distributed across networks of neurons. What we remember can be influenced by what happened afterward, what we currently believe, how we feel when we retrieve it, and even what other people have told us about the event.

Maybe that's why two siblings can grow up in what appears from the outside to be the same house and somehow describe two different childhoods. I don't think either one necessarily owns the correct version. They had the same home and family, but in another sense, they didn't. They occupied different positions inside it. They experienced different interactions. They noticed different things. Their brains kept different pieces.

That makes me wonder how much of the person I believe myself to be is already a reconstruction.

There are things I don't consciously remember that still seem to have left something behind. I think the body can remember in ways that don't feel like remembering. That's not mystical. Neuroscience distinguishes between explicit memory, which involves conscious recollection, and forms of implicit memory that can influence behavior without requiring us to deliberately replay an event. A learned motor skill is an easy example. You don't consciously retrieve instructions for every movement when you ride a bicycle. Emotional learning can work beneath conscious recollection too. The nervous system can learn associations between cues and safety, reward or threat.

So it is possible for an experience to stop existing as a clear little story in your head while still influencing what feels familiar, frightening or safe. I find that comforting and unsettling in almost equal amounts. If I forgot everything about someone I loved, would I still love them?

My first instinct is no.

If you walked into a room and I didn't know your name, didn't know how we met, couldn't remember a single conversation we'd had and had no idea what our relationship was, I don't think I could honestly say I loved you simply because my body felt comfortable around you. I might be drawn to you. I might trust you without understanding why. I might want you to stay. Maybe something in me would recognize something in you even if I couldn't explain it, but I think I would have to build a relationship with you again.

The reverse doesn't work for me either. If I could recite your birthday, remember every vacation we'd taken, describe our inside jokes and tell someone exactly how we met, but I felt absolutely nothing when I looked at you, I don't think I would call that love either.

Apparently, for me, loving someone requires both the history and the feeling.

This question isn't entirely hypothetical in my family.

My grandfather has Alzheimer's disease.

Alzheimer's gets reduced to memory loss so often that I think we accidentally make it sound like extreme forgetfulness. It isn't. Alzheimer's is a progressive neurodegenerative disease, meaning cells and connections in the brain are gradually damaged and lost. It is also the most common cause of dementia. Dementia isn't one specific disease. It is a term for a collection of cognitive symptoms severe enough to interfere with daily life, and Alzheimer's is one disease that can cause it.

One reason memory problems often appear early is that Alzheimer's affects brain regions involved in forming new memories, including areas around the hippocampus. This is why early Alzheimer's may look less like someone dramatically forgetting their entire childhood and more like someone repeatedly forgetting something that happened this morning. They may ask the same question again, lose track of dates, misplace things in unusual places, struggle with planning or become confused in familiar situations. Memory problems are common early signs, but Alzheimer's can also affect language, judgment, spatial abilities, mood and behavior. As disease spreads through more of the brain, those problems become more extensive. The microscopic story is even stranger.

Two proteins come up constantly when we talk about Alzheimer's: amyloid beta and tau. Amyloid beta can accumulate between neurons and form plaques. Tau normally helps stabilize structures inside neurons that are important for transporting materials through the cell, but in Alzheimer's, abnormal tau accumulates into tangles inside neurons. These processes are associated with disrupted communication between brain cells, inflammation, synaptic dysfunction and eventually neuronal death. And these changes don't necessarily begin when someone starts forgetting things. Research suggests that Alzheimer's related brain changes can begin a decade or more before noticeable problems with memory and thinking appear. Someone can therefore be living through a biological process in their brain without knowing it is happening yet. Though, having some Alzheimer's associated brain changes does not automatically mean that a person will develop dementia. I find that terrifying and scientifically fascinating at the same time. Because memory is not disappearing from some abstract place. The tissue responsible for creating, retrieving and connecting parts of a person's life is physically changing. That clinical explanation still doesn't tell you what Alzheimer's looks like from the other side of the dinner table.

My grandfather is still my grandfather.

He is quieter now. He can sit in silence for long stretches, and he doesn't like people helping him even when we understand that he needs help. He isn't as interactive as I remember him being. But there are mannerisms that are unmistakably his. His food preferences are still there. His affection is there. His habits and jokes appear. I say hello and sometimes he pauses for a long time and looks at me. I don't experience the look as blank. It feels like he is taking me in. Maybe I interpret it that way because I still see him as him.

There was a day when he was visiting and refused to eat dinner because he said he didn't want to eat without my grandmother. She had been dead for more than a decade.

There is something devastating about what Alzheimer's can do to time. The present can become unreliable while something from years ago feels immediate enough to determine whether you eat dinner tonight. That isn't necessarily because Alzheimer's neatly erases memories from newest to oldest like someone deleting files in order. The disease is much more complicated than that. Different neural networks and different kinds of memory can be affected differently, and the pattern changes as the disease progresses. But difficulty learning and retaining new information is particularly common early on. Later, people may lose more of their personal history and have increasing trouble with language, reasoning, reading, writing, familiar tasks and recognizing people. In severe disease, a person may eventually become unable to communicate and dependent on others for their care.

I don't know what was happening inside my grandfather's mind at that dinner table, and I don't want to turn one moment into a neurological diagnosis. I just remember hearing him say he wouldn't eat without my grandmother and thinking about how strange memory is. A person can lose access to something the rest of us consider basic reality and still hold onto another person so tightly that she belongs at the dinner table more than ten years after she's gone.

My memories of my grandparents are complicated too. My grandmother died when I was young, and sometimes it hurts that I don't remember more of her. I have photographs. I have other people's stories. I know I loved her. I know I was loved by her. I know the family felt different when she was alive. Looking backward, she feels like the glue. My grandfather lost his wife, eventually retired and moved away, and something about that whole period feels like the ending of a version of our family that I was too young to understand was ending. I wish I had saved more of it in my own head.

That's probably part of why Alzheimer's frightens me so much. I already know what it feels like to want a memory that my brain did not keep. The fear becomes more complicated because Alzheimer's has a genetic component, and this is where the science gets both more reassuring and more frustrating.

There is no single “Alzheimer's gene” responsible for most cases. The most common form is late onset Alzheimer's, usually developing after age 65. Its genetics are complicated. Many genetic variants can influence susceptibility, while age, health and environmental factors matter too. One of the strongest known genetic risk factors is a version of the APOE gene called APOE ε4. APOE normally helps the body transport cholesterol and other fats. We inherit one APOE allele from each biological parent, and the common versions are called ε2, ε3 and ε4. ε3 is the most common. ε2 may offer some protection in some populations, while ε4 is associated with increased Alzheimer's risk and, in some groups, earlier disease onset. Having two ε4 copies generally carries more risk than having one.

But risk is not destiny, which is probably the most important sentence in this entire genetics section.

Someone can inherit APOE ε4 and never develop Alzheimer's. Someone who doesn't carry ε4 can still develop it. Genetic ancestry can also affect how strongly certain variants are associated with risk, and researchers are still trying to understand those differences. APOE testing therefore cannot simply tell a healthy person, “You will get Alzheimer's” or “You won't.”

There are rare situations where genetics are much more direct. Disease causing variants in APP, PSEN1 and PSEN2 can cause rare inherited forms of Alzheimer's that often appear before age 65. If a biological parent carries one of these pathogenic variants, each child has a 50 percent chance of inheriting that altered gene. These families are very different from the much more common situation of having an older relative who developed late onset Alzheimer's.

I think that distinction matters because “my grandfather has Alzheimer's” can turn into “Alzheimer's runs in my family,” and that can very quickly turn into “this is waiting for me.” Science doesn't actually allow me to make that leap. Emotion does.

My grandfather having Alzheimer's makes genetics feel less like something I read about and more like something that could be sitting quietly somewhere inside my own DNA. I don't know what I carry, and part of me is scared to know. There is a strange tension between being fascinated by genetics and knowing that sometimes information cannot give you control. I could know more about my probability without knowing my future.

I think about that when I think about having children.

I love children. I love taking care of them and having them around me. But I also think I could have a meaningful life without having my own, and genetics is one of the things that makes that possibility feel less frightening to me than it might to someone else. There are things I am scared of having, scared of knowing I have, and even more scared of imagining passed into another generation. Alzheimer's is one of those fears.

I know that fear can run ahead of the science. Having a grandfather with Alzheimer's is not proof that I will develop it, and it definitely isn't proof that my hypothetical children would. Family history is one piece of risk, not a diagnosis written generations in advance. Even biomarkers associated with Alzheimer's cannot currently tell a healthy person with certainty whether they will eventually develop the disease.

Knowing that doesn't make the possibility emotionally disappear.

What scares me most isn't simply forgetting facts. I don't care very much whether an 80 year old version of me remembers everything she learned in biology. I hope she does, but if she can't explain a signaling pathway anymore, I don't think that is what would make me mourn her. I don't think losing the titles of books I've read would be the worst part either.

I am afraid of forgetting my family.

I am afraid of looking at someone who has loved me for forty years and seeing a stranger. I am afraid of my children, if I have them, having to introduce themselves to their mother. I am afraid of people sitting beside me with decades of memories that I can no longer access. I think it would hurt if I were still aware enough to understand what was happening. Imagine knowing that the person holding your hand is important because everyone keeps telling you so, while desperately searching your own mind for the reason.

And then there is the possibility that I wouldn't understand enough to be devastated by it.

Maybe I wouldn't know my husband anymore, but his hand would still feel safe in mine. I think that would comfort me. It would also break my heart now, while I am still capable of imagining it. If I were confused enough not to understand what I had lost, maybe I would simply enjoy the comfort. Maybe the person beside me would be carrying the grief for both of us. That is what I meant when I once thought about Alzheimer's as making the people who love you lose you twice. There can be losses before death. A shared memory disappears for one person but remains perfectly intact for the other. A name goes. A face becomes difficult to place. A story that used to belong to two people suddenly belongs to one.

But I hesitate to say that the person themselves is already gone. I don't feel that way about my grandfather.

I still feel loved by him. I still see him inside his mannerisms, preferences, affection and jokes. Alzheimer's can eventually affect far more than memory, including personality, behavior, communication and independence, but it does not unfold identically in every person or erase every ability at once. My grandfather still feels like himself to me, and I don't know exactly how much of that is him remaining recognizable and how much is my own memory filling in what disease has changed.

Maybe that is part of loving somebody too. We carry versions of one another. My parents remember a baby I cannot remember being. My siblings know things about my childhood that have completely disappeared from my brain. Friends can repeat something I once said and surprise me with my own words. There are versions of me stored in other people's minds that I will never have access to again. In a strange way, other people become external pieces of our autobiographies.

That doesn't mean their memories are perfectly accurate either. Their brains reconstruct too. But maybe identity was never something we carried entirely by ourselves. I keep coming back to a thought experiment. Imagine I am very old and I find this blog. I don't recognize it. I start reading and slowly realize that the person who wrote all of these essays is me. There are thoughts about science, family, love, fear and stupid little things I apparently cared enough about to spend hours writing down. I find photographs I don't remember taking. I read stories about people whose faces no longer immediately produce names. Maybe I learn that I used to love literature and biology. Maybe I read an essay called “Could I still be me without my memories?” and find it slightly obnoxious that my younger self apparently spent this much time worrying about the exact thing that eventually happened to us.

Would I feel like I was recovering myself? Or would I feel like I was reading about a stranger? Probably both.

I don't think I would want to choose which memories survive. If someone offered me five memories guaranteed to remain forever, I don't know which five I would pick. The obvious answer would be the happiest or most important ones, but even that feels wrong. Who am I to decide, from where I am standing now, which five moments deserve to represent an entire life? What if something I consider ordinary today becomes the thing I would have wanted most at eighty?

And if I could erase one horrible memory completely, I don't think I would.

Not because suffering automatically makes us stronger or because every horrible thing secretly happens for a reason. I don't believe pain needs that kind of justification. I just don't know how to remove an experience from myself without wondering what else I would accidentally remove with it. Maybe a fear came from it. Maybe a boundary did too. Maybe compassion. Maybe a decision I made years later without realizing where it began.

Experiences can outlive our ability to tell their stories. That may be the strangest answer I've found to the question I started with.

Could I still be me without my memories? I don't think I would be completely me.

If you removed my autobiographical memory, I don't think you could simply point to my body and say nothing important had changed. The story I tell myself about who I am matters. The people I recognize matter. Knowing where I came from matters. Memory gives continuity to a life that would otherwise be a series of disconnected present moments. But I also don't think memory contains all of me.

If I forgot everything about my life and somehow still loved animals, still reached toward books, still wanted to feed people, still found myself curious about something I couldn't explain, still made the same stupid jokes, still felt safe beside certain people, still wanted to take care of someone who needed help, I think there would be something beautiful about that.

Imagine forgetting the entire story of how you became yourself and still, somehow, behaving like the person you spent a lifetime becoming.

Maybe that wouldn't be enough for me to say nothing had been lost. A lot would have been lost. I don't want to make Alzheimer's poetic because it isn't. Alzheimer's eventually destroys more than a collection of memories. In advanced disease, people can lose the ability to communicate, recognize their surroundings, control aspects of movement and independently perform basic activities. They can become completely dependent on other people for care. It is a physical disease of the brain, not a beautiful metaphor for forgetting.

But disease affecting a person is not the same thing as disease making that person's entire existence disappear. Maybe that's what my grandfather is teaching me without meaning to.

I don't know everything he remembers. I don't know what happens during the long pauses when he looks at me. I don't know whether my face immediately connects to my name every single time. I don't know what parts of our family's history are still available to him or what pieces have become unreachable. I know he is still there. And maybe someday, if my own memory begins to fail me, the people I love will know things about me that I don't.

They will know what I used to read. They will know what made me laugh. They will know the stories I told too many times and the foods I always made and the animals I brought home when I probably shouldn't have. They will know which version of me existed at twenty three because apparently she left an unreasonable amount of writing behind.