What is Alzheimer's Disease? - Causes, Symptoms & Treatment

Instructor: Devin Kowalczyk

Devin has taught psychology and has a master's degree in clinical forensic psychology. He is working on his PhD.

Sometimes referred to as 'old-timers,' the neurological disorder is a highly disruptive and debilitating disease that many find confusing, frustrating, and exhausting to deal with. In this lesson we'll review the causes, symptoms, and current treatment options.

Alzheimer's, the Disease

Alzheimer's disease was first identified in 1906 by a physician named Alois Alzheimer after performing an autopsy and discovering unusual build up in the brains of a few elderly patients. It is one of the most common forms of dementia, but is also one of the most difficult to actually diagnose.

Alzheimer's is a neurodegenerative disorder, in which neurons in the brain begin failing to produce sufficient neurotransmitters, and eventually begin to die off. Alzheimer's disease is a specific type of dementia, which is a type of global brain degeneration affecting thinking, planning, and memory.

Your brain is composed of (estimated) billions of specialized cells called neurons whose sole purpose is to carry a signal and trigger other cells. Neurons in your arm cause your muscles to move, neurons in your heart cause it to beat, and neurons in your brain carry signals to other neurons, giving you thoughts and memories. A certain group of these neurons begin to die in your brain, or they degenerate (called neurodegeneration) due to two reasons:

  • Beta amyloid plaques: a sticky protein that lumps together and forms hardened shells on cells (think of it like layers of tar building up and drying on a cell, building and drying, until the cell dies underneath them)
  • Neurofibrillary tangles: bundles of fibers that build up in a cell, choking it to death (kind of like you eating straws. If you keep eating them they will build up inside of you and eventually kill you).

Neurofibrillary Tangle

It's unclear whether this is caused by the disease or if it's a byproduct of something else. For instance, Alzheimer's has been found to have a strong genetic link, and it may be a series of defective proteins producing the plaques and tangles.

Ultimately, something is causing the disease to kill off portions of the brain in a slow way. The brain begins this degeneration typically in an area called the basal forebrain ('bottom front brain') and degrades outward from there. This lets us predict the symptoms due to the progression it takes.


Officially, a diagnosis of Alzheimer's can only be made after death with an autopsy examination of the brain. However, the symptoms will typically follow a particular path and this will allow for an earlier, provisional diagnosis to allow for treatment.

Neurodegeneration is detected on autopsy


Alzheimer's disease is not typical aging. It typically affects those older than 65, but is much more severe. With typical aging, there is a slowing down of the thought process and it becomes more difficult to form new memories and pull more recent memories out.

Typical aging issues:

  • Grandma Jen temporarily forgot my new dog's name, Ru-ru.
  • Grandpa John lost his keys and the remote.
  • Great Uncle Steve forgot his new address.

However, these issues are generally temporary; Grandpa John may lose his keys for a while and find them later, but he hasn't forgotten how to drive or what a key is used for. Symptoms of Alzheimer's must cause significant impairment and progressively become worse over time. These symptoms may include:

  • Inability to remember new information or previously learned information
  • Impairment in language (can't find a word or say something else), typical movement (walking, picking up something), recognition of objects or faces, or organizing/planning behaviors (start drinking before they pick up a cup)
  • Confusion over time and place (not remembering what season it is, not remembering how they arrived in their current location, not realizing that time has passed)
  • Decreases in problem-solving and decision-making abilities
  • Mood or personality changes, which may include becoming fearful, suspicious, depressed, anxious or easily upset

Alzheimer's disease is not:

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