My neighbor was taking one of his thrice-daily
strolls with his caregiver, Celia, the other day
when he stopped in front of a tissue discarded on
the hallway floor. Moving to pick it up, he was
stopped by Celia. “He likes to pick things up off
the floor whether they belong to him or not,” she
I smiled empathetically as she gently put his
hand back on the walker’s handle. “He wants his own
way all the time; and if he doesn’t get it, he gets
angry,” she said.
“Although several years younger, my dad is the
same,” I told her. “He wants to be in charge.”
“He’s been living with Alzheimer’s disease,” one
doctor told us. He was right, it turns out; AD is
the most common — yet not the only — form of
dementia in people 65 and older, according to
Alzheimer’s Weekly, and accounts for between 50
and 70 percent of all dementias.
Dementia is defined as “a collection of symptoms
that are caused by disorders affecting the brain and
is not one specific disease” by Alzheimer’s
Australia, the peak group that provides support and
advocacy for the 257,000 Australians living with it.
While the cause of most dementia is unknown, its
final stage involves loss of memory, reasoning,
speech, and other cognitive functions, and risks of
developing dementia increase with age, according to
the National Institute on Aging.
Caused by a variety of illnesses, dementia can
occur as the result of a stroke (vascular dementia),
Parkinson's disease, a brain tumor, a thyroid or
other metabolic or endocrine disorder, or any number
of reasons; proper diagnosis is necessary to ensure
Data from the 2007 nationally-representative
Health and Retirement study concluded that one in
seven Americans over age 70 has some form of
Dementia classifications group disorders that
have similar features, such as whether they are
progressive or what parts of the brain are affected.
The National Institute of Neurological Disorders and
Stroke lists some frequently-used classifications:
Cortical dementia — brain damage
primarily affects the brain's cortex, or outer
layer; tends to cause memory, language, thinking,
and social behavior problems.
Subcortical dementia — affects
parts of the brain below the cortex; tends to cause
emotional and movement changes and memory problems.
Progressive dementia — gets
worse as time passes and gradually interferes with
more and more cognitive abilities.
Primary dementia — doesn’t
result from another disease.
Secondary dementia — occurs as
the result of a physical disease or injury.
AD is both a progressive and a cortical dementia.
One common type of progressive dementia is Lewy body
dementia (LBD), which can occur sporadically in
people who have no known family history of this,
although rare familial cases are occasionally
Symptoms of LBD overlap with AD in many ways and
can include memory impairment, poor judgment, and
confusion. People living with LBD can have visual
hallucinations, a shuffling gait and flexed posture
— symptoms of Parkinson’s disease — and severity of
symptoms can vary daily.
Other types of dementia include:
AIDS-related dementia — Also
called AIDS dementia complex (ADC); can develop in
persons with human immunodeficiency virus (HIV) and
acquired immune deficiency syndrome (AIDS). While
uncommon in people who have early-stage HIV, it can
increase as HIV progresses, although not everyone
with HIV/AIDS develops ADC. Possible early-stage
symptoms include difficulty concentrating and
remembering phone numbers or appointments, slower
thinking and more time needed to finish complicated
tasks, irritability, unsteady walking, poor
coordination, and depression.
Creutzfeldt-Jakob Disease — This
is most common human form of a rare, fatal brain
disorder that affects people and certain mammals.
When variant CJD (“mad cow disease”) occurs in
cattle, it can be transmitted to people under
Frontotemporal dementia —
Includes other dementias like primary progressive
aphasia, Pick's disease and progressive supranuclear
palsy. Symptoms include personality and behavioral
changes and language difficulties.
Huntington’s disease — This is a
progressive brain disorder caused by a single
defective gene on chromosome 4, characterized by
abnormal involuntary movements, a severe decline in
thinking and reasoning skills, irritability,
depression and other mood changes.
Mixed dementia — More than one
type of dementia occurs at the same time in the
brain, most commonly AD and vascular dementia, and
can include DLB.
Normal pressure hydrocephalus —
Symptoms include walking difficulties, memory loss
and inability to control urination.
Parkinson’s disease — This can
result in progressive dementia as it develops,
similar to AD or DLB. Movement problems are a
symptom early on.
Vascular dementia — Previously
known as multi-infarct or post-stroke dementia, it’s
the second-most common cause of dementia after AD.
Initial symptoms can include impaired judgment or
ability to plan steps to complete a task, rather
than memory loss often associated with the initial
symptoms of AD.
Wernicke-Korsakoff Syndrome —
This chronic memory disorder is caused by severe
deficiency of thiamine (vitamin B-1) and the effect
of alcohol on absorption and use of thiamine. Its
most common cause is alcohol misuse. Symptoms
generally include impaired learning ability,
personality changes, problems with memory and
balance, and difficulty with clear thinking and
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