Most people picture Alzheimer’s starting with memory loss — forgetting names, missing appointments, losing the thread of a conversation. That’s real, but it’s often not where the disease actually begins.
A growing body of research over the past several years suggests the earliest detectable changes can show up in places you wouldn’t expect: your sense of smell, your sleep patterns, your motivation to do things, even your bank statements. Some of these changes may appear years, sometimes over a decade, before a diagnosis.
This article walks through what the research actually says — not what’s scary, not what’s speculative, just what’s been measured. If you’re reading this because you’re worried about your own health or a loved one’s, that instinct to pay attention is a good one. But one symptom on this list, on its own, is not a diagnosis. These are patterns researchers have found across large groups of people, not a checklist for any one individual.
Why “Earliest Signs” Is a Moving Target
Alzheimer’s disease isn’t a single event — it’s a slow biological process. Changes in the brain, including the buildup of amyloid and tau proteins, can begin ten to twenty years before someone shows obvious symptoms. That long runway is exactly why researchers have spent the last several years trying to find the earliest possible markers, using tools ranging from smell tests to blood draws to credit reports.
It’s also why this list isn’t organized by “worst to least bad.” These are different windows into the same underlying process, each identified through different kinds of studies.
1. A weakening sense of smell
A 2022 study from the University of Chicago followed 515 older adults for years, testing their ability to identify common smells. People whose sense of smell declined rapidly over time were more likely to show smaller gray matter volume in brain regions tied to memory and smell — the same regions affected in Alzheimer’s — even before any diagnosis.
A related NIH-led study found that for every point drop in odor identification test scores, participants had a 22% higher chance of developing mild cognitive impairment.
A 2023 follow-up published in Alzheimer’s & Dementia reinforced this, showing that a single smell test can predict cognitive decline for up to 15 years afterward, and that people who show rapid olfactory decline are more likely to convert from normal cognition to MCI, and from MCI to Alzheimer’s.
Brain imaging studies have also found that people with mild cognitive impairment show reduced activation in brain circuits tied to both smell and memory when exposed to odors.
Why smell specifically? The brain regions responsible for identifying odors sit close to, and are wired into, the same memory circuits that Alzheimer’s affects early on. That overlap is likely why a change in smell can show up before a change in memory becomes obvious.
Worth knowing: Smell naturally dulls somewhat with age, and can also be affected by sinus issues, smoking, colds, or unrelated neurological conditions. One bad cold isn’t a red flag. Researchers are looking at sustained, unexplained decline over time.
2. Losing motivation
Apathy is a measurable loss of goal-directed behavior — not sadness, not grief, just a flattening of drive. Someone might stop initiating hobbies they used to enjoy, stop reaching out to friends, or seem content to do nothing for long stretches, without reporting feeling sad about it.
A 2022 study presented at the Alzheimer’s Association International Conference followed nearly 4,000 people and found that those with persistent apathy — even with completely normal cognition at the time — had a 2.69 times greater risk of developing dementia than those without it.
A broader review published in 2023 confirmed apathy is one of the most common early neuropsychiatric symptoms tied to what researchers now call “mild behavioral impairment,” a syndrome increasingly viewed as running parallel to, and sometimes ahead of, cognitive symptoms.
One detail researchers have zeroed in on: the person experiencing apathy often doesn’t notice it themselves. Several studies rely on a caregiver or family member reporting the change, because awareness of one’s own motivation shift can be part of what’s affected.
If you’re the one reading this and worried about yourself: the fact that you’re self-monitoring and asking questions is itself a different pattern than what these studies describe. Apathy tends to be noticed by the people around someone, not sought out by the person themselves.
3. Changes in sleep — both too little and too irregular
Sleep and Alzheimer’s appear to have a two-way relationship: poor sleep may accelerate the buildup of amyloid in the brain, and early Alzheimer’s-related changes may in turn disrupt sleep. Because of that loop, researchers have spent real effort trying to figure out which comes first.
A large 2023 analysis using ten years of national U.S. data found that specific sleep disturbances — trouble falling asleep and needing medication to sleep — were associated with a measurably higher risk of a later dementia diagnosis.
A 2023 study published in Neurology found that people with highly irregular sleep schedules — going to bed and waking at inconsistent times — had a higher risk of dementia than people with consistent sleep patterns, independent of how many total hours they slept.
A 2023 meta-analysis pooling data across 31 longitudinal studies found that short sleep duration (six hours or less) was linked to a 46% increased risk of dementia in shorter-term follow-ups.
This doesn’t mean one bad week of sleep is meaningful — researchers are describing sustained patterns tracked over years, often measured against a person’s own baseline. Sleep is also affected by dozens of far more common and treatable things: stress, pain, medication side effects, sleep apnea, and hormonal shifts among them. If sleep has changed for you, that’s worth mentioning to a doctor regardless — good sleep matters for brain health either way.
4. Difficulty adapting when plans change
This is some of the newest research on the list. A study from Texas A&M Health, published in mid-2026, looked at executive function — specifically, the mental flexibility involved in adjusting to new information or changed circumstances — rather than memory.
Using an animal model, researchers found that difficulty with “reversal learning” — updating a decision after the rules change — appeared before measurable memory problems did. The implication is that struggling to adapt when a plan shifts, or feeling unusually thrown off by a change in routine, might reflect early brain changes before memory itself is affected.
This research is still early — it’s based on animal models, not yet large human trials — but it fits a broader pattern researchers are increasingly interested in: that the earliest signs of Alzheimer’s may show up in how the brain processes and adjusts, not just in what it remembers.
5. New trouble managing money
This is one of the more surprising, and more thoroughly documented, findings of the last several years — and it comes with real financial stakes.
A study led by researchers at Johns Hopkins, published in JAMA Internal Medicine, linked Medicare records to credit report data and found that people who were later diagnosed with dementia showed a measurable decline in their credit scores and an increase in missed payments — starting as early as six years before diagnosis.
A related 2024 analysis found that household wealth dropped significantly faster, over an eight-year window, in people who went on to be diagnosed with dementia compared to those who weren’t.
The pattern researchers describe isn’t a single missed bill — it’s things like: consistently forgetting routine payments (utilities, insurance, mortgage), new difficulty balancing a checkbook or reading a bank statement, uncharacteristic impulsive purchases, or increased vulnerability to scams.
One study found older adults who were cognitively “normal” on standard testing but who fell for financial scams were still at meaningfully higher long-term risk of later cognitive decline.
Researchers involved in this work have specifically noted that this window — where financial mismanagement appears years before a diagnosis — is an underused opportunity for family members to notice something is off, and to put safeguards like a power of attorney in place early, calmly, and collaboratively.
6. What’s now detectable in a blood draw
This is arguably the biggest shift in Alzheimer’s research over the last few years: for the first time, a specific blood biomarker — p-tau217 — can flag Alzheimer’s-related brain changes with real accuracy, without a spinal tap or a PET scan.
A large study published in JAMA in 2024 found that a blood test measuring p-tau217 and related markers predicted an Alzheimer’s diagnosis with 88–92% accuracy — outperforming standard clinical evaluations done by doctors using physical exams and cognitive testing alone. Because of results like this, p-tau217 testing became commercially available through major lab companies starting in 2024.
More recent research has pushed the timeline back even further. A 2026 study presented at the Alzheimer’s Association International Conference and published simultaneously in JAMA followed nearly 3,000 people who were symptom-free at the start. Those with very high p-tau217 levels had roughly a 78% chance of developing cognitive impairment within ten years — and even people with only mildly elevated levels had a meaningfully increased risk.
This matters for two reasons. First, it means researchers can now study “silent” Alzheimer’s-related brain changes in people who feel completely normal, which is reshaping how early-stage prevention trials are designed. Second, it means a conversation with a doctor about cognitive concerns no longer has to start with an invasive test — a blood draw can now be part of the picture.
This test is not a stand-alone diagnostic tool for otherwise healthy people, and it’s not currently a recommended screening test for everyone. It’s used alongside a full clinical evaluation, and results are generally interpreted by a physician familiar with the person’s full health picture. A high number on a blood test is a data point, not a verdict.
7. Getting lost or disoriented in familiar places
This is closer to the “classic” signs most people associate with Alzheimer’s, but recent research has sharpened exactly what’s different about it in the earliest stages.
It’s not about occasionally missing a turn on an unfamiliar road — everyone does that. What researchers focus on is disorientation in places someone has known for years: a regular grocery store, their own neighborhood, a relative’s house they’ve visited dozens of times.
A large systematic review and meta-analysis of pre-diagnostic Alzheimer’s symptoms, covering studies through 2023, found that spatial and navigational difficulties were among the more consistently reported pre-diagnostic changes across dozens of long-term cohort studies. That same review, which screened over 11,000 abstracts down to 30 qualifying long-term studies, is one of the more comprehensive attempts to map out what actually shows up before a formal diagnosis, rather than after.
The reason spatial memory tends to be affected early ties back to brain anatomy again — the hippocampus, one of the first regions Alzheimer’s-related changes tend to appear in, is central to both memory formation and spatial navigation. That overlap is part of why “getting turned around somewhere familiar” shows up on so many early-symptom lists, and why it’s taken seriously by clinicians rather than dismissed as normal absent-mindedness.
8. Repeating questions or stories without noticing
Nearly everyone forgets they’ve already told a particular story once in a while. What researchers are describing is something different in degree: repeating the same specific question or story multiple times within a short window, with no awareness that it’s already been said.
This symptom is harder to study formally because it usually isn’t self-reported — the person doing the repeating typically isn’t aware of it. Most of the research relies on family members or close friends noticing the pattern and later mentioning it during a formal cognitive workup. That’s part of why researchers increasingly emphasize the role of a close companion’s observations, not just self-report, in early detection efforts — the person experiencing the earliest changes is often the least equipped to notice them.
Why Researchers Now Talk About “Clusters,” Not Single Symptoms
Fewer researchers treat any single item on this list as meaningful in isolation. Instead, the framework increasingly used is “mild behavioral impairment” (MBI) — a term that groups together apathy, mood changes, impulse changes, and social withdrawal as a cluster that, together, carries more predictive weight than any one piece alone.
If someone has always been a homebody who isn’t particularly social, low social engagement alone tells you very little. But a new, sustained shift — someone who used to call friends weekly and now doesn’t, who used to manage their own finances confidently and no longer does, who used to navigate their neighborhood easily and now sometimes doesn’t — clustering across categories is what researchers pay more attention to than any single item checked off a list.
What a Doctor Actually Does With This Information
If any of this prompts a visit to a doctor, it helps to know roughly what that visit tends to involve, so it feels less like an unknown.
Most primary care doctors start with a standard cognitive screening tool — a short set of questions and simple tasks that takes a few minutes, not a long invasive process. They’ll typically also run basic blood work to rule out far more common and treatable causes of cognitive or behavioral changes: thyroid problems, vitamin B12 deficiency, medication side effects, and signs of depression are all standard first checks, because each of these can produce symptoms that look similar to early Alzheimer’s but are unrelated and often reversible.
If initial screening raises a genuine concern, a doctor may refer to a neurologist or a memory clinic for more detailed cognitive testing, brain imaging, or — increasingly, given the research above — a blood test for biomarkers like p-tau217. None of this happens in a single visit, and none of it requires arriving with a firm diagnosis in mind. Describing what’s changed, in plain terms, is enough to start.
What Connects All of This
Looking at this research as a whole, a few things stand out:
- The disease is rarely announced by one dramatic moment. These studies are almost all about patterns over time — a smell test that gets worse year over year, a sleep schedule that becomes erratic, a credit score that starts slipping. Isolated, one-off changes are common in everyday life and usually mean nothing.
- Most of these signs have far more common explanations. Trouble sleeping is more often stress, pain, or a medication side effect. Apathy is far more often burnout or depression. Money trouble is far more often a temporary financial squeeze. Alzheimer’s is one possible explanation among many, and statistically, usually not the most likely one — especially in people who are younger or have no family history.
- Noticing something and naming it are two different steps. If any of this resonates — for yourself or someone you care about — the useful next step is a conversation with a primary care doctor, not a self-diagnosis. Doctors can rule out far more common and treatable causes (thyroid issues, vitamin deficiencies, medication interactions, depression, sleep apnea) before Alzheimer’s is even part of the conversation.
- Earlier awareness is generally a good thing, not a frightening one. The entire reason researchers have pushed so hard to find earlier and earlier signs is that earlier identification opens the door to more treatment options, more time to plan, and more ability to put support systems in place while someone can still be fully part of that planning. Finding this information now, before there’s a crisis, is generally protective — not something to dread.
If you’re someone who tends to worry about health changes generally, it may help to remember: Research like this exists precisely because these signs are common and usually explained by something else. A single bad night of sleep, one missed bill, or briefly losing your sense of smell during a cold is not a study finding — it’s just being human.
If persistent worry about symptoms like these is affecting your daily life, that’s also worth mentioning to a doctor. Health anxiety is real, treatable, and separate from the underlying question of whether any particular symptom means something serious.