Overview

Alzheimer's disease is a progressive neurodegenerative disorder that primarily affects older adults. It damages brain cells over time, leading to worsening problems with memory, cognition, behavior, and the ability to perform daily activities. Although there is no cure, treatments can help manage symptoms and improve quality of life.

Alzheimer's is the most common cause of dementia, accounting for 60–90% of all cases. In the U.S. alone, over 6 million people aged 65 and older live with Alzheimer's. As the population ages, this number is expected to double by 2060 without a major medical breakthrough.

Types

There are two main types of Alzheimer's disease:

Early-Onset Alzheimer's

Affects people in their 30s to mid-60s. It accounts for fewer than 10% of cases. It tends to have a stronger genetic link and may progress more aggressively.

Late-Onset Alzheimer's

This type is far more common, typically beginning after age 65. People diagnosed in their mid-60s may live 4–8 more years on average, though some survive 20 years or more.

Mild Cognitive Impairment (MCI)

MCI is a condition marked by subtle cognitive changes that don’t yet interfere significantly with daily life. Around 50% of MCI cases are due to early-stage Alzheimer's, but some may reverse or stabilize, especially when caused by temporary factors.

Causes

Alzheimer's is a neurodegenerative disease caused by damage to brain cells. This damage leads to shrinkage and inflammation in the brain. Two hallmark features of Alzheimer's include:

  • Amyloid plaques: Clumps of toxic beta-amyloid protein that build up between neurons.

  • Tau tangles: Abnormally twisted tau proteins that accumulate inside neurons and disrupt nutrient transport.

While amyloid and tau have long been central to understanding the disease, emerging research suggests other factors may also play significant roles. The exact cause remains unknown, but genetic, environmental, and lifestyle factors are believed to interact.

Risk Factors

Several factors are associated with an increased risk of developing Alzheimer's:

  • Age: Risk rises significantly after age 65.

  • Genetics and family history: Genes like APOE-e4 are linked to greater risk, especially in early-onset cases.

  • Cardiovascular conditions: High blood pressure, heart disease, and stroke are major contributors.

  • Metabolic factors: Midlife obesity, diabetes, and low HDL cholesterol levels raise the risk.

  • Depression: Untreated depression in midlife is associated with higher Alzheimer's risk.

  • Social isolation: Loneliness and lack of engagement increase vulnerability.

  • Head trauma: Moderate to severe traumatic brain injury significantly raises risk.

  • Smoking and heavy alcohol use: Both contribute to cognitive decline.

  • Hearing loss: May also be linked to a higher risk of dementia.

Symptoms

Alzheimer's symptoms typically start with memory issues and gradually progress. Early signs include:

  • Forgetting recent events or conversations

  • Difficulty solving problems or completing familiar tasks

  • Confusion about time or place

  • Challenges with language and finding words

  • Poor judgment and decision-making

  • Withdrawal from work or social activities

  • Mood and personality changes

In later stages, individuals may:

  • Lose the ability to communicate coherently

  • Exhibit aggressive or impulsive behavior

  • Struggle with basic self-care, including eating and hygiene

  • Develop hallucinations or paranoia

Stages

Alzheimer's is commonly divided into three stages:

Mild (Early Stage)

  • Increasing memory lapses

  • Trouble managing finances or planning

  • Changes in personality and judgment

  • Often still able to live independently

Moderate (Middle Stage)

  • Worsening confusion and memory loss

  • Difficulty recognizing family or friends

  • Repetitive behavior, wandering, or delusions

  • Need for greater supervision

Severe (Late Stage)

  • Loss of ability to respond or communicate

  • Total dependence for personal care

  • Inability to swallow, leading to risk of aspiration pneumonia

Diagnosis

Early diagnosis is essential for planning care and accessing available treatments. Diagnosis typically includes:

  • Medical history and symptom review

  • Cognitive tests (e.g., memory, language, attention)

  • Neurological and psychiatric evaluations

  • Brain imaging (MRI, CT, PET scans)

  • Blood and urine tests to rule out other causes (e.g., thyroid issues, vitamin B12 deficiency)

Other conditions that mimic Alzheimer's, such as depression, medication side effects, or sleep apnea, must be excluded.

Treatment

There is no cure for Alzheimer's, but treatment focuses on slowing progression and improving quality of life.

Medications for Symptoms

  • Cholinesterase inhibitors (e.g., donepezil, rivastigmine): Boost levels of communication between nerve cells.

  • Memantine: Regulates glutamate, a brain chemical involved in learning and memory.

These medications may temporarily help with symptoms like memory loss and confusion but do not stop disease progression.

New Therapies

  • Aducanumab (Aduhelm): Targets amyloid buildup. Approved by the FDA under controversy and limited availability.

  • Ongoing research explores other drugs targeting tau, inflammation, and immune responses.

Behavioral Management

  • Medications may be prescribed for agitation, aggression, or psychosis, but with caution due to side effects.

Non-Drug Therapies

Lifestyle adjustments and supportive interventions can help manage symptoms:

  • Exercise: May slow cognitive decline and improve mood.

  • Cognitive stimulation: Activities like puzzles or crafts support mental engagement.

  • Music therapy: Enhances memory and mood.

  • Routine and structure: Helps reduce confusion and anxiety.

  • Support groups: Beneficial for caregivers and patients alike.

Prevention

There’s no guaranteed way to prevent Alzheimer's, but certain strategies may lower your risk:

  • Maintain heart health: Control blood pressure, cholesterol, and blood sugar.

  • Stay mentally active: Read, learn, and challenge your brain regularly.

  • Stay socially engaged: Interaction helps preserve cognitive health.

  • Eat a brain-healthy diet: Like the Mediterranean or DASH diets.

  • Avoid smoking and limit alcohol.

  • Exercise regularly.

Living With Alzheimer’s

Alzheimer’s is life-changing for both patients and caregivers. Planning ahead and building a care team can improve outcomes.

Helpful strategies:

  • Establish routines

  • Use reminders and labels

  • Modify the home for safety

  • Consider respite care or adult day programs

Support is essential for caregivers, who may experience burnout or depression. Access to counseling, resources, and community programs can help manage the burden.