2.  Alzheimer’s disease occurs when the brain begins to
develop plaques (structures that are formed when
axons and dendrites begin to break down) and tangles
(structures that form in the brain from the breakdown
of axons and dendrites). People with Alzheimer’s
disease may remember how to do something, like play
a game, but they may not remember whether they
have taken their turn. It might be like if you were
playing baseball and you remembered how to hit the
ball with the bat, but you couldn’t remember whether
it was your turn at bat or if you had just taken your
turn.

3.  People with Alzheimer’s disease are said to have good
procedural memory (memory for motor skills such as
how to hit a ball with the bat) but they may have
trouble with declarative memory (memory that a
person can state in words).
 Alzheimer’s disease gets worse over time, so people
will have more serious memory loss, feel
confused, experience depression, and other problems.
It is much more common as people get older, and
almost 50% of people over the age of 85 have
Alzheimer’s disease.

4.  Alzheimer’s disease is not the same as the kind of
forgetting that can occur when people get older, but is
a real disease caused by major changes in the way the
brain functions. When a person develops Alzheimer’s
disease, a gene causes the protein that brain cells
normally contain to begin behaving abnormally. This
produces a protein known as amyloid beta protein 42.
This protein accumulates in the brain and damages the
membranes of axons and dendrites, and this causes
the plaques to form. Another protein that accumulates
abnormally with Alzheimer’s disease is called the tau
protein, and produces the tangles seen with
Alzheimer’s disease.

5.  This accumulation of abnormal chemicals produces by
these changes in the brain damages many brain
areas, including the basal forebrain area, a structure in
the front of the brain that is necessarily for
communication with the rest of the cerebral cortex.
People with Alzheimer’s disease have difficulty
concentrating and paying attention to ordinary life
events because of this damage, and this causes
problems with behavior and with memory.

6. Brain Cross-Sections
A normal brain on
the left and a brain of
a person with
Alzheimer’s disease
on the right. Notice
how much smaller
the memory part of
the brain at the
bottom of the picture
is for the person with
Alzheimer’s disease
as compared to the
normal brain.

7.  There is no cure for Alzheimer’s disease, and the
symptoms always get worse, but certain drugs that can
help increase attention can cause people to behave
more normally for a longer period of time than they
would be able to without the drug. There are also more
experimental treatments that are being tried that
should help people who develop Alzheimer’s disease in
the future.