Alzheimer’s

Alzheimer’s Disease is a progressive neurological disorder that causes brain cells (neurons) to degenerate and die, leading to a continuous decline in cognitive function, memory, and behaviour. It is the most common cause of dementia, accounting for 60-80% of dementia cases. Alzheimer’s is a slow-developing disease that typically affects people aged 65 and older, though early-onset Alzheimer’s can occur in people in their 40s or 50s.

What Happens in Alzheimer’s Disease?

Alzheimer’s disease gradually destroys brain cells and affects how the brain functions. It begins in regions responsible for memory and eventually spreads to other areas, causing a range of cognitive and behavioural changes. The disease progresses through several stages: mild, moderate, and severe, with symptoms worsening over time.

How Alzheimer’s Affects the Brain

Plaques and Tangles

Amyloid Plaques: Alzheimer’s is characterized by the accumulation of beta-amyloid, a sticky protein that clumps together to form plaques in the brain. These plaques are toxic to brain cells and disrupt communication between neurons.

Tau Tangles: Another key feature is the formation of neurofibrillary tangles, made of a protein called tau. In healthy neurons, tau helps stabilize the internal structure of the cell. In Alzheimer’s, tau becomes abnormal, forming tangles inside the cells that disrupt their function and ultimately lead to cell death.

Brain Shrinkage

As neurons die and synapses (connections between brain cells) break down, the brain shrinks (atrophy) over time. The hippocampus, the part of the brain involved in forming new memories, is often the first to be affected. As Alzheimer’s progresses, other regions of the brain responsible for language, reasoning, and decision-making also begin to shrink.

Loss of Communication Between Neurons

Neurons communicate with one another via electrical and chemical signals at synapses. In Alzheimer’s, the build up of plaques and tangles interferes with these signals, leading to disruptions in communication. This causes memory problems, confusion, and difficulty in learning new information.

Inflammation and Oxidative Stress

In Alzheimer’s, immune cells in the brain (called microglia) try to clear away the plaques, but this immune response can lead to inflammation and further damage to the brain. Additionally, oxidative stress from free radicals damages cells and contributes to the progression of the disease.

Reduction in Neurotransmitters

Neurotransmitters like acetylcholine are essential for communication between neurons, especially in areas of the brain related to memory and learning. In Alzheimer’s, levels of these chemicals decrease, leading to impairments in cognitive function.

Stages of Alzheimer’s Disease

1. Preclinical Stage (No Symptoms)
   During this stage, changes in the brain (such as the formation of plaques and tangles) may begin, but there are no noticeable symptoms. This stage can last for years or even decades before cognitive decline becomes evident.
2. Mild (Early-Stage)
   Memory lapses and subtle problems with thinking and reasoning start to appear. People may have trouble remembering recent conversations, names, or where they placed items. They may also struggle with tasks that require concentration or planning.
3. Moderate (Middle-Stage)
   In this stage, memory loss worsens, and individuals may need help with daily activities such as dressing or bathing. Behavioural changes like agitation, wandering, confusion about time or place, and mood swings often occur.
4. Severe (Late-Stage)
   In the final stage, individuals lose the ability to communicate and become completely dependent on others for care. They may lose the ability to walk, sit, or even swallow. The brain has significantly shrunk, and almost all cognitive function is severely impaired.

Symptoms of Alzheimer’s Disease

• Memory Loss: The most common and early symptom, particularly difficulty remembering recent events or new information.
• Confusion: Disorientation about time, place, and familiar tasks.
• Language Problems: Difficulty finding words or following conversations.
• Difficulty with Planning and Problem Solving: Struggling to manage daily tasks, like paying bills or following recipes.
• Mood and Behaviour Changes: Anxiety, depression, aggression, irritability, and withdrawal from social activities.
• Difficulty in Performing Familiar Tasks: Activities that were once routine, such as driving or cooking, become challenging.