Alzheimer's Disease: Causes, Symptoms & Treatment

Alzheimer's disease is a progressive neurodegenerative disorder and the most common cause of dementia, accounting for 60 to 80% of all dementia cases. It is characterized by the gradual destruction of brain cells, leading to progressive decline in memory, thinking, behavior, and the ability to perform everyday activities. The disease typically progresses over 4 to 8 years after diagnosis, though some people live up to 20 years.

Approximately 6.7 million Americans age 65 and older are living with Alzheimer's disease. The risk increases significantly with age, roughly doubling every 5 years after age 65.

Preclinical Alzheimer's (no symptoms):

• Brain changes (amyloid buildup) begin 15-20 years before symptoms appear
• No outward signs of cognitive decline

Mild cognitive impairment (MCI) due to Alzheimer's:

• Noticeable memory problems greater than expected for age
• Still able to carry out daily activities independently
• Not all MCI progresses to Alzheimer's

Mild Alzheimer's dementia:

• Memory lapses affecting daily life (forgetting recent events, repeating questions)
• Difficulty with planning, organization, and problem-solving
• Getting lost in familiar places
• Trouble handling money and bills
• Personality changes (withdrawal, apathy, mood changes)

Moderate Alzheimer's dementia (longest stage):

• Increased memory loss and confusion
• Inability to learn new things
• Difficulty with language (finding words)
• Problems recognizing family and friends
• Wandering, agitation, suspiciousness
• Needs help with daily activities (dressing, bathing)

Severe Alzheimer's dementia:

• Loss of ability to communicate coherently
• Complete dependence on others for care
• Loss of awareness of surroundings
• Difficulty swallowing
• Loss of mobility

• Age: The strongest risk factor
• Genetics: APOE-e4 gene variant increases risk; rare familial forms involve APP, PSEN1, or PSEN2 mutations
• Family history: First-degree relative with Alzheimer's increases risk
• Down syndrome: Higher risk due to extra copy of chromosome 21 (which carries the APP gene)
• Cardiovascular risk factors: Hypertension, diabetes, high cholesterol, obesity
• Head trauma: Especially repeated traumatic brain injuries
• Lower education and social isolation: Less cognitive reserve
• Hearing loss: Emerging evidence links untreated hearing loss to increased dementia risk

• Cognitive assessments: Mini-Mental State Exam (MMSE), Montreal Cognitive Assessment (MoCA)
• Neuropsychological testing: Detailed evaluation of memory, language, executive function
• Brain MRI: Shows brain atrophy patterns (hippocampal atrophy is characteristic)
• PET scans: Amyloid PET or tau PET can detect protein deposits
• Cerebrospinal fluid (CSF) analysis: Measures amyloid-beta and tau protein levels
• Blood tests: Newer blood biomarkers (plasma amyloid, p-tau) are becoming available for screening

There is currently no cure, but treatments can help manage symptoms and, in some cases, modestly slow progression:

Medications for cognitive symptoms:

• Cholinesterase inhibitors (donepezil, rivastigmine, galantamine): For mild to moderate disease; modestly improve cognition and daily function
• Memantine: For moderate to severe disease; regulates glutamate activity
• Anti-amyloid antibodies (lecanemab, donanemab): Newer treatments that remove amyloid plaques and may slow cognitive decline in early Alzheimer's (modest but measurable benefit)

Medications for behavioral symptoms:

• Antidepressants for depression and anxiety
• Antipsychotics cautiously for severe agitation or psychosis (increased mortality risk in elderly)
• Melatonin for sleep disturbances

Non-pharmacological approaches:

• Structured daily routines
• Cognitive stimulation and engagement
• Physical exercise (shown to improve cognition and behavior)
• Music therapy and art therapy
• Caregiver education and support
• Safety modifications in the home

While there is no guaranteed way to prevent Alzheimer's, evidence supports these strategies to reduce risk:

• Regular physical exercise (most robust evidence)
• Cognitive engagement and lifelong learning
• Social connection and community involvement
• Heart-healthy diet (Mediterranean diet)
• Adequate sleep
• Hearing aid use when appropriate
• Management of cardiovascular risk factors
• Avoidance of excessive alcohol and head injuries

See a doctor if you or a loved one experiences persistent memory problems that interfere with daily life, difficulty with familiar tasks, confusion about time or place, or personality changes. Early diagnosis allows for better planning and access to treatments.