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Dementia in Amyotrophic Lateral Sclerosis (Lou Gehrig's Disease)

What is Dementia in ALS?

Patient Comments
  • Amyotrophic lateral sclerosis (ALS) is a devastating disorder. It affects the part of the nervous system that controls voluntary movements. ALS is sometimes called Lou Gehrig's disease, after the famous baseball player who died of the disease. The muscles become progressively weaker, and the disease eventually leads to paralysis and death.
  • ALS is one of a group of diseases known as motor neuron diseases. Neurons are nerve cells, and motor neurons control movement. Persons with motor neuron disease gradually lose muscle control and become paralyzed. No cure is available for ALS or any other motor neuron disease.
  • The effects of these diseases are not reversible. Most people with ALS die within 5 years of the onset of symptoms.
  • Most experts believe that ALS does not affect a person’s mental processes. In most people, neither cognitive processes (such as thinking, learning, memory, and speech) nor behavior is affected. Occasionally, however, a person with ALS does experience profound mental changes, which are called dementia. Dementia is a severe brain disorder that interferes with a person’s ability to carry out everyday activities.
  • Dementia in ALS is thought to be due to destruction of cells in the frontal lobe of the brain. The frontal lobe is the part of the brain from the forehead back to the ears. This type of dementia is often called frontal lobe dementia. Frontal lobe dementia has other causes besides ALS. We are still learning about why ALS causes frontal lobe dementia in some people.
  • Dementia is rare in ALS. It occurs in all ethnic groups and in both men and women. People aged 55-65 years are most likely to be affected.

Dementia in ALS Causes

We do not know what causes frontal lobe dementia in people with ALS. A few people have a family history of this type of dementia, but we do not understand the connection between this dementia and ALS. More than one cause may be involved.

Medically Reviewed by a Doctor on 7/19/2016
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  • Dementia is a decline and/or loss of memory, reasoning, judgment, behavior, language and other mental abilities that are not a part of normal aging; it usually progressively worsens over time.
  • Dementia, senility, and Alzheimer's disease are not the same things.
  • In general, there are many causes of dementia, but all dementia diseases result from dysfunction of a person's cerebral cortex, directly or indirectly.
  • There are irreversible, and potentially reversible causes of dementia.
  • Early signs and symptoms of dementia may go unrecognized, but the first sign is usually loss of short-term memory.
  • Some of the other early dementia symptoms and signs include:
    • Personality changes
    • Mood swings
    • Poor judgment
    • Paranoia or suspiciousness

Read What Your Physician is Reading on Medscape

Dementia in Motor Neuron Disease »

Most patients with motor neuron disease (MND) are free of cognitive impairment, but there is growing evidence of an association between MND and frontal lobe or frontotemporal dementia (FTD).

Read More on Medscape Reference »

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