Why is memory affected by senile dementia?

Senile dementia, often used synonymously with Alzheimer's disease, does indeed adversely impact memory function due to various factors:

A-beta plaques and tau tangles: Alzheimer's disease is hallmarked by the presence of amyloid-beta (A-beta) plaques and tau tangles in the brain. A-beta plaques are formed by the accumulation of amyloid-beta proteins outside the nerve cells, while tau tangles are twisted strands of a protein called tau that accumulate inside affected nerve cells. These abnormal formations hinder communication between neurons and lead to impaired cognitive functions, including memory loss.

Loss of neurons: The hippocampus, a brain region vital for memory formation and consolidation, is severely affected in senile dementia. Degeneration and loss of nerve cells (neurons) occur within the hippocampus, leading to diminished ability to learn new information and retrieve stored memories.

Changes in neurotransmitter levels: Neurotransmitters are chemical messengers that facilitate communication between brain cells. In senile dementia, there is a disruption in the functioning and levels of essential neurotransmitters like acetylcholine, serotonin, and dopamine. These imbalances further contribute to memory problems.

Structural changes in brain regions: Neuroimaging studies in individuals with senile dementia have revealed changes in the structure and size of various brain regions associated with memory, such as the hippocampus and temporal lobes. Notably, the volume of the hippocampus tends to decrease with the progression of cognitive decline.

Inflammation: Persistent inflammation within the brain is believed to play a significant role in the neuropathology of senile dementia. It is thought that ongoing inflammatory processes contribute to neuronal damage and impairment of neural circuits involved in memory.

It's worth mentioning that senile dementia affects not only memory but various other cognitive functions and daily activities, making it a highly debilitating neurodegenerative disorder.