What is Alzheimer's disease?

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Last updated: April 14, 2025View editorial policy

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From the Guidelines

Alzheimer's disease is a malignant and devastating condition characterized by global cognitive impairment, leading invariably to dependence and finally death. According to the ESPEN guidelines on nutrition in dementia 1, it is a clinical syndrome that represents a decline from the previous level of cognitive functioning, associated with impairment in functional abilities and, in many cases, behavioral and psychiatric disturbances. The disease is the most common cause of dementia, accounting for a significant proportion of cases, and is often accompanied by other disorders such as cerebrovascular dementia.

Key characteristics of Alzheimer's disease include:

  • A decline in memory and at least one other cognitive domain, such as language, visuospatial, or executive function
  • Impairment in functional abilities and behavioral and psychiatric disturbances
  • A strong association with age, genetic risk factors, and cardiovascular health issues
  • A potential link to lifestyle factors such as low educational level or head trauma

The disease causes a high burden of suffering for patients, their families, and society, leading to increased anxiety, depression, and dependency, as well as complicating other comorbid conditions 1. The annual societal cost of dementia is substantial, due to healthcare and related costs as well as lost wages for patients and family caregivers.

In terms of risk factors, having a first-degree relative with a history of Alzheimer's disease, having the apolipoprotein ε4 genotype, or suffering from Down syndrome are all associated with an increased risk of developing the disease 1. Additionally, cardiovascular risk factors such as hypertension are associated with an increased risk for both Alzheimer's disease and vascular dementia.

Overall, Alzheimer's disease is a complex and multifaceted condition that requires a comprehensive approach to management and care, taking into account the patient's cognitive, functional, and behavioral needs, as well as their overall quality of life 1.

From the Research

Definition of Alzheimer's Disease

Alzheimer's disease (AD) is a type of neuropsychiatric illness that affects the central nervous system, characterized by the accumulation of amyloid-beta and phosphorylated tau (P-tau) protein 2.

Symptoms and Effects

The disease leads to cognitive, functional, behavioral, and global changes, including:

  • Cognitive decline
  • Functional impairment
  • Behavioral changes
  • Global deterioration

Treatment Options

Several medications are used to treat AD, including:

  • Cholinesterase inhibitors (donepezil, rivastigmine, galantamine)
  • NMDA receptor antagonist (memantine) These medications aim to stabilize or slow the decline in cognitive, functional, and behavioral aspects of AD 3, 4.

Efficacy and Safety

Studies have shown that these medications have significant effects on cognitive, functional, and behavioral outcomes, but may also have adverse effects, such as gastrointestinal and non-gastrointestinal adverse events 3, 4, 5.

  • Donepezil, rivastigmine, and galantamine have been shown to be effective in treating mild to moderate AD, with donepezil being the most widely studied and having a lower incidence of gastrointestinal adverse events 5.
  • Memantine has been shown to be beneficial in stabilizing or slowing the decline in cognitive and functional aspects of AD, but its effect on behavioral outcomes is less clear 4, 6.

Cost-Effectiveness

The cost-effectiveness of these medications has been evaluated, with results suggesting that they may be beneficial, but the cost savings associated with reducing the mean time spent in full-time care do not offset the cost of treatment sufficiently to bring estimated cost-effectiveness to levels generally considered acceptable by healthcare policymakers 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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