Alzheimer’s, a neurodegenerative disease that affects millions of people worldwide, is known for its devastating impact on memory and cognitive function. However, identifying its early signs can be key to early diagnosis and better management. Recent research has highlighted that an early symptom, mild memory loss associated with difficulty recalling recent events, can be a critical indicator.

According to studies, up to 80% of people who experience this symptom, known as mild cognitive impairment (MCI), will develop Alzheimer’s in the following years. This article explores this early sign, its meaning, and how to take action to protect brain health, with a clear, professional, and accessible approach.

What is Alzheimer’s and why is it important to detect it early?

Alzheimer’s is a progressive disease that affects brain cells, causing memory loss, thinking difficulties, and behavioral changes. According to the Alzheimer’s Association (2025), more than 55 million people are living with dementia worldwide, with Alzheimer’s accounting for up to 70% of cases. Although there is no cure, early detection allows access to treatments that slow its progression, improve quality of life, and plan for the future.

Dr. Maria Carrillo, scientific director of the Alzheimer’s Association, explains: “Identifying early signs, such as mild cognitive impairment, is crucial because it gives us a window to intervene before brain damage becomes extensive.” The transition from mild symptoms to Alzheimer’s can take years, underscoring the importance of acting at the first signs.

The First Sign: Mild Cognitive Impairment (MCI)

Mild cognitive impairment is an intermediate state between normal aging and dementia. It is characterized by memory or thinking problems that are more noticeable than typical age-related changes, but not severe enough to significantly interfere with daily life.

According to a study published in Neurology (2024), 80% of people with amnestic MCI (which primarily affects memory) will develop Alzheimer’s within 5 to 10 years.

How does MCI manifest?

The most common signs of Alzheimer’s-related MCI include:

Difficulty remembering recent events: For example, forgetting a doctor’s appointment or what you ate for breakfast, but remembering events from decades ago.

Repeating questions or stories: Asking the same thing multiple times in a conversation without realizing it.

Word-finding problems: Difficulty remembering common terms or substituting incorrect words.

Mild disorientation: Getting lost in familiar places or forgetting the current date.

Difficulty with complex tasks: Trouble planning a meal, managing finances, or following detailed instructions.

Practical example: A 68-year-old woman notices that she frequently forgets where she parked her car or repeats the same story to her children. Although she can still manage her daily routine, these episodes are more frequent than before, which could indicate MCI.

Why do 80% of people with MCI develop Alzheimer’s?

Amnestic MCI is closely linked to Alzheimer’s disease because it reflects early damage to brain areas such as the hippocampus, which is crucial for memory. Brain imaging studies, such as those published in The Lancet Neurology (2024), show that people with MCI often have beta-amyloid plaques and tau tangles, pathological hallmarks of Alzheimer’s disease, even before symptoms become severe.

The risk of progression to Alzheimer’s disease depends on several factors:

Age: People over 65 with MCI are more likely to develop the disease.

Genetics: The presence of the APOE4 gene increases the risk by up to 30%, according to the Journal of Alzheimer’s Disease (2024).

Other risk factors: High blood pressure, diabetes, depression, or previous head trauma accelerate progression.

MCI severity: Those with more pronounced memory problems are at higher risk.

For example, a 70-year-old man with MCI who has the APOE4 gene and uncontrolled diabetes has a significantly higher chance of developing Alzheimer’s than someone without these factors.

Other early signs to watch out for

In addition to MCI, other early symptoms may indicate a risk of Alzheimer’s, especially if combined with memory problems:

Mood or personality changes: Unusual irritability, apathy, or anxiety.

Visual-spatial difficulties: Trouble judging distances, reading, or recognizing faces.
Loss of initiative: Decreased interest in previously pleasurable activities.

Judgment problems: Making inappropriate financial decisions or neglecting personal hygiene.

Practical example: A 65-year-old man who forgets appointments and shows apathy toward his favorite hobbies, such as playing chess, could be showing early signs of Alzheimer’s beyond MCI.

How do you know if you have a problem?

If you notice memory or thinking problems that worry you, it’s crucial to act immediately. Here’s how to assess whether you might have MCI or a risk of Alzheimer’s:

Initial self-assessment:

Do you forget recent events more often than before?
Do you have trouble following conversations or finding words?
Do you notice you need more reminders for everyday tasks?
If you answer “yes” to several of these questions, seek a medical evaluation.

Consult a specialist:

Visit a neurologist or geriatrician for a full evaluation.
Describe your symptoms in detail and mention any family history of Alzheimer’s or dementia.

Diagnostic tests:

Cognitive tests: Assessments such as the Mini-Mental State Examination (MMSE) or the Montreal Cognitive Assessment (MoCA) measure memory, language, and other functions.

Blood tests: Biomarkers such as tau protein or beta-amyloid can indicate Alzheimer’s risk, according to Nature Medicine (2024).

Brain imaging: MRIs or PET scans detect brain atrophy or plaque buildup.

Genetic testing: Although not routine, they can identify the APOE4 gene in high-risk cases.

Observation of loved ones:

Family members often notice changes before the affected person. If your loved ones express concern, take it seriously.

Practical example: A 70-year-old woman who misses appointments asks her daughter to accompany her to the neurologist. A MoCA test reveals MCI, and an MRI shows early brain changes, leading to an immediate treatment plan.

Risk factors that increase the likelihood

In addition to MCI, certain factors increase the risk of progressing to Alzheimer’s:

Advanced age: The risk doubles every five years after age 65.

Family history: Having a first-degree relative with Alzheimer’s increases the risk by 10–30%.

Unhealthy lifestyle: Diets high in saturated fat, a sedentary lifestyle, and lack of sleep contribute to brain damage.

Medical conditions: Hypertension, obesity, type 2 diabetes, and cardiovascular disease damage brain vessels.

Lack of mental stimulation: Low intellectual or social activity accelerates cognitive decline.

For example, a 68-year-old person with MCI who eats a diet high in fried foods and lacks exercise has a higher risk than someone with healthy habits.