Alzheimer

About the disease

Alzheimer’s Disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia in older adults. It is characterized by gradual cognitive decline affecting memory, language, orientation, judgment, and other higher mental functions, significantly interfering with patients’ daily lives.

Pathophysiology

Two main alterations are observed in the brains of people with Alzheimer’s:

• Beta-amyloid plaques: extracellular accumulations of amyloid protein fragments (Aβ), especially the Aβ-42 form, which interfere with neuronal communication.
• Neurofibrillary tangles: intracellular aggregates of hyperphosphorylated tau protein that disrupt the structure of neuronal microtubules, compromising stability and cellular transport.

These changes lead to synaptic loss, brain atrophy, and neuronal death, particularly in regions such as the hippocampus and cerebral cortex, which are essential for memory and thinking.

Clinical Progression

The disease generally develops in three phases:

• Preclinical phase: brain changes without evident symptoms.
• Prodromal phase: mild cognitive impairment, with measurable memory failures but no significant functional impact.
• Dementia phase: progressive loss of autonomy, affecting multiple cognitive and functional domains. Within this phase, three stages are distinguished: mild, moderate, and severe dementia.

Diagnosis

Diagnosis is based on clinical evaluation, neuropsychological tests, and brain imaging studies. In recent years, blood and cerebrospinal fluid biomarkers have been developed, allowing detection of the disease in early stages, even before symptoms appear.

Treatment

Although there is currently no cure, available treatments aim to control symptoms and their progression, as well as improve patients’ quality of life. These include:

• Symptomatic medications: such as acetylcholinesterase inhibitors and memantine.
• Disease-modifying therapies: such as anti-amyloid monoclonal antibodies.
• Non-pharmacological interventions: cognitive stimulation, physical exercise, psychosocial support, and personalized care.

Impact and Future

In Portugal, it is estimated that around 90,000 people have Alzheimer’s disease, and this number is expected to increase in the coming decades due to population aging. Current research focuses on identifying early biomarkers, developing disease-modifying treatments, and improving comprehensive patient and caregiver management.

Alzheimer’s disease affects not only patients but also their caregivers, having a profound emotional, physical, social, and economic impact.