can be a sign of a more serious problem.

Dementia is the term for a decline

in memory and other cognitive functions

that gets to the point of interfering with daily life.

Dementia results from excessive damage

to brain tissue, which can be from multiple strokes

or other causes.

The most common form of dementia is Alzheimer's disease, or AD.

Now, the exact cause of AD is still unknown,

but we do know that in people with AD,

their neurons die off over time.

As people with AD lose their neurons and synapses,

their cerebral cortex shrinks in size.

The earliest symptoms of AD are memory loss, specifically

the inability to encode or retrieve recent memories.

Subsequent problems include difficulty

with attention, planning, semantic memory,

and abstract thinking.

As the disease progresses, more severe language difficulties

may appear, as well as greater memory loss,

such as the inability to recognize close family

and friends.

As the disease continues to progress, people with AD

may experience emotional instability and loss of control

over their bodily functions.

While there are many theories as to the exact cause

of the disease, a definitive answer is still unknown,

and the disease is terminal.

We do know that people with AD experience

a buildup of proteins called amyloid plaques in the brain,

but how or why those plaques start to build up

and exactly what role they play in the disease is still

uncertain.

Another neurological disorder affecting memory

is Korsakoff's syndrome, which is

caused by a lack of vitamin B1, or thiamine, in the brain.

This disorder is strongly linked to severe malnutrition,

eating disorders, or especially alcoholism,

because these groups often don't ingest or are

unable to process all the nutrients their bodies need,

including thiamine.

Thiamine is important because it's

responsible for converting carbohydrates

into the glucose your cells need for energy,

and it's especially important for the normal functioning

of your neurons.

At first, a person developing Korsakoff's syndrome

might have damage to certain parts of the brain,

resulting in poor balance, abnormal eye movements,

mild confusion, and/or memory loss.

At this stage, it's actually called

Wernicke's encephalopathy, which is

the precursor to Korsakoff's syndrome.

If Wernicke's encephalopathy is diagnosed in time,

then it's possible to reverse the damage,

or at least prevent more of it.

If untreated, however, the disease

will progress into full-blown Korsakoff's syndrome.

The main symptom of Korsakoff's syndrome is severe memory loss,

and this symptom is often accompanied by confabulation,

which is when the patient makes up stories,

sometimes to fill in the gaps in his or her memory.

Unlike AD, Korsakoff's syndrome is not necessarily progressive.

If diagnosed and treated, people can get better.

People are often treated with thiamine injections

or other medication, and they have

to stay on a healthy diet and abstain from alcohol.

And some people may also need to re-learn some things.

The effectiveness of this treatment

really depends on how early the disease is diagnosed

and how well the patient follows the treatment guidelines.