Fast Five Quiz: Alzheimer's Disease Signs and Symptoms

Jasvinder P. Chawla, MD, MBA


February 22, 2022

Forgetfulness is typical in the normal course of aging. But forgetting recent events, conversations, or newly acquired information may be an early sign of AD because changes typically begin in the part of the brain that affects learning.

Still, there is overlap between the pathologic signs of normal aging and the symptoms of AD. In fact, when neuropathologists were blinded to clinical data in 2010, they mistakenly identified the disease in 76% of patients with healthy brains.

Many studies have reported that cerebral atrophy is significantly greater in patients with AD than patients who are aging normally, yet cerebral atrophy can be present in older adults and healthy individuals.

Oxidative stress is believed to play an influential role both in normal aging and in AD and other neurodegenerative diseases such as Parkinson's disease and amyotrophic lateral sclerosis. Generally, formation of free carbonyls and thiobarbituric acid–reactive products, an index of oxidative damage, are largely elevated in the brain tissue of patients with AD compared with the brain tissue of age-matched control patients.

The formation of neurofibrillary tangles (NFTs) may result first in malfunctions in communication between neurons and later in the death of the cells. Both senile plaques and NFTs are hallmarks of AD, but even they are not pathognomonic. NFTs can be found in other neurodegenerative disorders like progressive supranuclear palsy and dementia pugilistica (chronic traumatic encephalopathy). Senile plaques, too, may appear in normal aging.

Learn more about the pathophysiology of AD.


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