Alzheimer’s vs Parkinson’s: 7 Critical Differences Families Must Know

Alzheimer’s vs Parkinson’s—it’s a question many families ask when a loved one begins showing concerning symptoms. These two conditions are the most common neurodegenerative diseases affecting older adults in the United States, together impacting nearly 8 million Americans. That number is expected to double by 2050.

Because both conditions affect the brain and can cause cognitive changes, they’re easy to confuse. But understanding the differences between Alzheimer’s and Parkinson’s is crucial—especially when early symptoms could point to either condition.

This guide breaks down the 7 key differences between Alzheimer’s and Parkinson’s disease, including their causes, symptoms, and the latest treatments, so you can better understand what your family may be facing and what care options are available.

Alzheimer’s Disease: The Basics

Alzheimer’s disease is a progressive brain disorder that destroys memory and cognitive function. It causes 60% to 80% of all dementia cases, making it by far the most common cause of dementia in older adults.

Alzheimer’s by the Numbers (2025)

Almost two-thirds of Americans with Alzheimer’s are women. Older Black Americans are about twice as likely to have Alzheimer’s as older Whites, and older Hispanics are about one and one-half times as likely.

How Alzheimer’s Affects the Brain

In Alzheimer’s disease, two abnormal proteins build up in the brain:

→ Beta-amyloid plaques — Sticky clumps that form between brain cells and disrupt communication

→ Tau tangles — Twisted fibers that form inside brain cells and prevent nutrients from moving through them

These changes typically begin in the hippocampus—the part of the brain responsible for forming memories—before spreading to other regions. As more brain cells die, the brain actually shrinks.

Common Symptoms of Alzheimer’s

Early stage:

• Forgetting recently learned information
• Asking the same questions repeatedly
• Difficulty with planning or problem-solving
• Losing track of dates, seasons, or time
• Misplacing items and being unable to retrace steps

Middle stage:

• Forgetting personal history and major events
• Confusion about where they are or what day it is
• Difficulty recognizing family members
• Needing help with daily tasks like bathing and dressing
• Personality changes, including suspicion and agitation
• Wandering and getting lost

Late stage:

• Inability to communicate coherently
• Loss of awareness of surroundings
• Difficulty swallowing
• Loss of bladder and bowel control
• Requiring around-the-clock care

The average life expectancy after diagnosis is 4 to 8 years, though some people live as long as 20 years with the disease.

What Causes Alzheimer’s?

Scientists don’t fully understand what triggers Alzheimer’s, but research points to a combination of factors:

• Age — The biggest risk factor; risk doubles every 5 years after age 65
• Genetics — The APOE-e4 gene significantly increases risk
• Family history — Having a parent or sibling with Alzheimer’s increases risk
• Head injuries — Traumatic brain injury is linked to a higher risk
• Cardiovascular health — Heart disease, diabetes, high blood pressure, and obesity all increase risk

Treating Alzheimer’s Disease

A major breakthrough occurred in 2023-2024 with FDA approval of the first disease-modifying treatments for Alzheimer’s:

✓ Leqembi (lecanemab) — Approved July 2023. Slows cognitive decline by about 27% by clearing amyloid plaques from the brain. Administered via IV infusion every two weeks initially, with a monthly maintenance option approved in January 2025.

✓ Kisunla (donanemab) — Approved July 2024. Slows progression by about 29-35% over 18 months. Administered via monthly IV infusion, with the possibility of stopping treatment once scans show amyloid is cleared.

These treatments are only for people in the early stages of Alzheimer’s with confirmed amyloid plaques. They don’t cure the disease or reverse damage, but they can slow progression and help people maintain independence longer.

Other treatments focus on managing symptoms:

• Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) — Help with memory and thinking
• Memantine — Helps with moderate to severe symptoms
• Behavioral interventions — Music therapy, cognitive stimulation, structured routines

Professional caregiving is essential for people with Alzheimer’s. Because patients can forget where they are or what they’re doing, safety precautions and assistance with daily tasks help maintain quality of life and can delay the need for facility-based care.

Parkinson’s Disease: The Basics

Parkinson’s disease is a progressive neurological disorder that primarily affects movement. It’s the second most common neurodegenerative disease after Alzheimer’s and the most common movement disorder.

Parkinson’s by the Numbers (2025)

Parkinson’s is more common in men than in women. Geographic clusters have been identified in the “Rust Belt,” Southern California, Southeastern Texas, Central Pennsylvania, and Florida—regions with historical industrial or agricultural chemical exposure.

How Parkinson’s Affects the Brain

Parkinson’s disease develops when neurons in a part of the brain called the substantia nigra begin to die. These neurons produce dopamine, a chemical messenger that helps coordinate smooth, controlled movements.

When dopamine levels drop, the brain can no longer send proper movement signals—leading to tremors, stiffness, and difficulty controlling the body.

In Parkinson’s, abnormal clumps of a protein called alpha-synuclein (known as Lewy bodies) form inside brain cells, disrupting their function. This is different from the amyloid plaques and tau tangles seen in Alzheimer’s.

Common Symptoms of Parkinson’s

Motor symptoms (the hallmarks of Parkinson’s):

• Tremor — Shaking, usually starting in the hands or fingers
• Bradykinesia — Slowness of movement
• Rigidity — Stiff, inflexible muscles
• Postural instability — Balance problems and risk of falls
• Gait changes — Shuffling walk, freezing in place

Non-motor symptoms (often overlooked):

• Sleep disturbances (insomnia, REM sleep behavior disorder)
• Depression and anxiety
• Loss of sense of smell
• Constipation
• Soft or slurred speech
• Cognitive changes (in later stages)

Symptoms typically begin on one side of the body and remain worse on that side even as the disease progresses to both sides.

What Causes Parkinson’s?

The exact cause of Parkinson’s remains unknown, but contributing factors include:

• Age — Primary risk factor; most cases occur after age 60
• Genetics — Certain gene mutations increase risk, though hereditary Parkinson’s is rare
• Environmental toxins — Pesticides, herbicides, and industrial chemicals are linked to a higher risk
• Head trauma — Repeated head injuries may increase risk

Treating Parkinson’s Disease

There is currently no cure for Parkinson’s, but treatments can significantly improve quality of life:

Medications:

• Levodopa/carbidopa — The most effective treatment; converts to dopamine in the brain
• Dopamine agonists — Mimic dopamine’s effects
• MAO-B inhibitors — Prevent dopamine breakdown
• COMT inhibitors — Extend the effect of levodopa

Surgical options:

• Deep brain stimulation (DBS) — Electrodes implanted in the brain help regulate abnormal signals and reduce symptoms

Supportive therapies:

• Physical therapy for mobility and balance
• Speech therapy for communication difficulties
• Occupational therapy for daily living skills

Regular exercise is particularly important for people with Parkinson’s—research shows it may help slow symptom progression and improve mobility, balance, and quality of life.

Alzheimer’s vs. Parkinson’s: Key Differences

What These Conditions Have in Common

Despite their differences, Alzheimer’s and Parkinson’s share several important similarities:

Both Are Age-Related

Age is the greatest risk factor for both diseases. Of the 7.2 million Americans with Alzheimer’s, 74% are age 75 or older. Similarly, the vast majority of Parkinson’s cases occur after age 60.

Both Are Progressive and Incurable

Both diseases worsen over time as more brain cells die. While treatments can manage symptoms and—in Alzheimer’s case—slow progression, neither disease can currently be cured or reversed.

Both Are Neurodegenerative

Both diseases involve the progressive death of brain cells, though they affect different brain regions and involve different abnormal proteins.

Both Can Cause Dementia

While Alzheimer’s is defined by dementia, Parkinson’s can also lead to cognitive decline. Research shows that 50% to 80% of people with Parkinson’s eventually develop dementia, though it typically appears later in the disease course.

The dementia in each condition has different characteristics:

• Alzheimer’s dementia — Problems storing new memories; information is lost
• Parkinson’s dementia — Problems retrieving memories; information may be recalled with cues

Both Can Occur Together

Some people develop both conditions. Research has found significant overlap—many Parkinson’s patients show Alzheimer ‘s-related brain changes at autopsy, and many Alzheimer’s patients show Parkinson ‘s-related changes. Scientists are still working to understand the relationship between these diseases.

Both Require Comprehensive Caregiving

Both conditions eventually require assistance with daily activities. Professional home care can help with medication management, safety monitoring, mobility assistance, personal care, and provide respite for family caregivers.

How Home Care Can Help

Whether your loved one has Alzheimer’s, Parkinson’s, or both, professional in-home care can make a significant difference in their quality of life—and yours.

For Alzheimer’s disease, caregivers can help with:

• Medication reminders and management
• Safety supervision to prevent wandering
• Maintaining consistent daily routines
• Cognitive stimulation through activities and conversation
• Assistance with bathing, dressing, and personal care
• Meal preparation and nutrition support

For Parkinson’s disease, caregivers can help with:

• Fall prevention and mobility assistance
• Physical exercise and movement therapy support
• Medication timing (critical for symptom control)
• Help with fine motor tasks (buttoning, writing)
• Meal preparation and feeding assistance
• Communication support

In both cases, staying in a familiar home environment—rather than moving to a facility—can help maintain a sense of independence and dignity, reduce confusion and anxiety, and improve overall quality of life.

The Bottom Line

Alzheimer’s and Parkinson’s are both devastating diagnoses—but they are not the same disease, and understanding the differences matters for getting the right care and treatment.

→ Alzheimer’s primarily affects memory and cognition from the start

→ Parkinson’s primarily affects movement, with cognitive changes possible later

→ Both require early diagnosis and comprehensive care planning

The good news: breakthroughs are happening. The approval of disease-modifying treatments for Alzheimer’s in 2023-2024 represents a turning point, and research into both conditions continues at an unprecedented pace.

In the meantime, proper care—including professional home care—can help people with either condition maintain their quality of life, stay safe at home, and make the most of their time with family.

We Can Help

At All Heart Home Care, we provide specialized in-home care for seniors with Alzheimer’s disease, Parkinson’s disease, and other neurological conditions throughout San Diego County.

Our caregivers are trained to understand the unique challenges of each condition—from managing sundowning behaviors in Alzheimer’s to supporting safe mobility in Parkinson’s.

Call us at (619) 736-4677 for a free in-home consultation. We’ll assess your loved one’s needs and create a personalized care plan that supports their safety, independence, and quality of life.

References

• Alzheimer’s Association. 2025 Alzheimer’s Disease Facts and Figures. alz.org
• Parkinson’s Foundation. Statistics. parkinson.org
• FDA. FDA Approves Treatment for Adults with Alzheimer’s Disease (Kisunla). July 2024. fda.gov
• Alzheimer’s Association. Lecanemab Approved for Treatment of Early Alzheimer’s. alz.org
• American Brain Foundation. Disease Connections: Alzheimer’s and Parkinson’s. americanbrainfoundation.org
• BrightFocus Foundation. Alzheimer’s vs. Parkinson’s: A Comparison. February 2025. brightfocus.org
• The BMJ. Global projections of Parkinson’s disease prevalence to 2050. March 2025.