What types of dementia are there?

There are over 100 forms of dementia. By knowing the cause as early as possible, some effects can be treated, reversed or even cured.
There are over 100 forms of dementia. By knowing the cause as early as possible, some effects can be treated, reversed or even cured.

Much the same as cancer comes in many forms such as skin, colon or lung cancer, dementia (which describes a collection of symptoms, rather than a disease) comes in many forms, as well. While Alzheimer’s Disease is by far the most commonly known cause of dementia, research tells us that there can be nearly 100 different causes of dementia.

Research shows that memory loss can begin as early as age 45. Although dementia is generally progressive and incurable, there are exceptions. It’s only by properly diagnosing the cause of dementia as early as possible that its effects can be treated and in some cases reversed or even cured.

However, there is hope. “Although we don’t yet have a sure-fire way to prevent dementia, we do know that simple lifestyle changes – such as eating a healthy diet, not smoking, and keeping blood pressure and cholesterol in check – can all reduce the risk of dementia,” Dr. Simon Ridley, head of research at Alzheimer’s Research U.K., was quoted.

Alzheimer’s Disease

The most common form of dementia, Alzheimer’s Disease is responsible for 60 to 80 percent of dementia cases and is the sixth leading cause of death in the United States. While the greatest known risk factor for Alzheimer’s is increasing age (with the largest number of sufferers over age 65), early-onset Alzheimer’s affects approximately 200,000 Americans under the age of 65.

It is a progressive disease with no current cure where symptoms gradually worsen over a number of years. In its early stages, memory loss can be mild, but late-stage Alzheimer’s patients eventually lose the ability to carry on a conversation or respond to their environment.

Individuals diagnosed with Alzheimer’s live an average of eight years, but survival can range from four to twenty years depending upon age and other health conditions.

Vascular Dementia

The second most common form of dementia, vascular dementia is caused by a reduced flow of blood to the brain. This deprives the brain of the nutrients and oxygen that it needs to function normally. This particular form of dementia can result from a number of conditions that restrict the blood flow to the brain, including stroke, diabetes, uncontrolled high cholesterol, and hypertension.

The symptom of vascular dementia can differ significantly from those of Alzheimer’s. It can include problems with thinking, changes in personality or problems with movement. Patients with vascular dementia are encouraged to treat the underlying issues that may have caused the problem in the first place.

Mixed Dementia

Sometimes, dementia can be caused by more than one medical condition. When this happens, it is called Mixed Dementia. The most common form is caused by a combination of Alzheimer’s and Vascular Dementia.

Lewy Body Dementia or Dementia with Lewy Bodies (DLB)

Accounting for about 10-15% of dementia cases, DLB has symptoms similar to Alzheimer’s. However, it can also include visual hallucinations, sleep disorders and lack of attention. Parkinson’s disease-type symptoms such as slowed movements, muscle stiffness and tremors are also common.

Little understood by the scientific community, this type of dementia is characterized by abnormal protein deposits in nerve cells in the brain stem. Like Alzheimer’s, symptoms progressively worsen over time and, given its complex and little-understood nature, treatment can be difficult.

Experts believe that both DLB and Parkinson’s disease dementia (see below) are two different expressions of the same underlying problems with the brain. This, as the Alzheimer’s Association notes, “Many people with Parkinson’s eventually develop problems with thinking and reasoning, and many people with DLB experience movement symptoms, such as hunched posture, rigid muscles, a shuffling walk and trouble initiating movement.”

They also note that symptoms of DLB may include:

  • Changes in thinking and reasoning
  • Confusion and alertness that varies significantly from one time of day to another or from one day to the next
  • Parkinson’s symptoms, such as a hunched posture, balance problems, and rigid muscles
  • Visual hallucinations
  • Delusions
  • Trouble interpreting visual information
  • Acting out dreams, sometimes violently, a problem known as rapid eye movement (REM) sleep disorder
  • Malfunctions of the “automatic” (autonomic) nervous system
  • Memory loss that may be significant but less prominent than in Alzheimer’s

With no cure to slow or stop the damage caused by DLB, treatment focuses on helping control symptoms with anti-depressants and other medication.

Frontotemporal Dementia

Also known as FTD, frontal lobe dementia and Pick’s Disease, Frontotemporal Dementia accounts for less than 5% of all dementia cases but is the second most cause of dementia in those under 65.

A relatively rare form of dementia, FTD damages the brain cells in the frontal and temporal lobes. This affects the individual’s behavior and personality before any loss in memory or speech problems.

According to the Alzheimer’s Association, there are several key differences between FTD and Alzheimer’s Disease:

  • Age at diagnosis may be an important clue. Most people with FTD are diagnosed in their 40s and early 60s. Alzheimer’s, on the other hand, grows more common with increasing age.
  • Memory loss tends to be a more prominent symptom in early Alzheimer’s than in early FTD, although advanced FTD often causes memory loss in addition to its more characteristic effects on behavior and language.
  • Behavior changes are often the first noticeable symptoms in bvFTD, the most common form of FTD. Behavior changes are also common as Alzheimer’s progresses, but they tend to occur later in the disease.
  • Problems with spatial orientation—for example, getting lost in familiar places — are more common in Alzheimer’s than in FTD.
  • Problems with speech. Although people with Alzheimer’s may have trouble thinking of the right word or remembering names, they tend to have less difficulty making sense when they speak, understanding the speech of others, or reading than those with FTD.
  • Hallucinations and delusions are relatively common as Alzheimer’s progresses but relatively uncommon in FTD.

There is currently no cure and the progression cannot be slowed. Any treatment can only look to help manage symptoms.

Korsakoff Syndrome

Related to a deficiency in Vitamin B1 (thiamine), Wernicke-Korsakoff Syndrome most commonly occurs in alcoholics, though it can also be caused by malnutrition, cancer, abnormally high thyroid levels, long-term dialysis and long-term diuretic therapy (used to treat congestive heart failure).

According to the Alzheimer’s Association, it “is often, but not always, preceded by an episode of Wernicke encephalopathy, which is an acute brain reaction to severe lack of thiamine. Wernicke encephalopathy is a medical emergency that causes life-threatening brain disruption, confusion, staggering and stumbling, lack of coordination, and abnormal involuntary eye movements.

“Because the chronic memory loss of Korsakoff syndrome often follows an episode of Wernicke encephalopathy, the chronic disorder is sometimes known as Wernicke-Korsakoff syndrome.”

The symptoms of dementia in Korsakoff Syndrome include confusion, permanent gaps in memory, impaired short-term memory and hallucinations. The Alzheimer’s Association notes that “Memory problems may be strikingly severe while other thinking and social skills are relatively unaffected.

“For example, individuals may seem able to carry on a coherent conversation, but moments later be unable to recall that the conversation took place or to whom they spoke.

“Those with Korsakoff syndrome may “confabulate,” or make up, the information they can’t remember. They are not “lying” but may actually believe their invented explanations. Scientists don’t yet understand why Korsakoff syndrome may cause confabulation.”

Parkinson’s Disease Dementia

Like Alzheimer’s, Parkinson’s Disease is a chronic, progressive neurological condition. While not everyone who has Parkinson’s Disease will develop dementia, it can occur in 50 to 80 percent of patients, affecting reasoning, memory, speech, judgment and plan the steps needed to complete a task.

Much the same as Lewy Body Dementia, the brain changes linked to Parkinson’s Disease Dementia is caused by Lewy Body deposits. Another complicating factor is that many of those with both Lewy Body Dementia and Parkinson’s Disease Dementia also have the signature plaques and tangles in their brains linked to Alzheimer’s Disease. Common symptoms include:

  • Changes in memory, concentration, and judgment
  • Delusions, especially paranoid ideas
  • Depression
  • Irritability and anxiety
  • Muffled speech
  • Sleep disturbances, including excessive daytime drowsiness and rapid eye movement (REM) sleep disorder
  • Trouble interpreting visual information
  • Visual hallucinations

According to the Alzheimer’s Association:

Parkinson’s disease dementia is diagnosed when a person who has originally been diagnosed with Parkinson’s based on their movement symptoms begins to exhibit dementia after a year or more.

Dementia with Lewy bodies, on the other hand, is diagnosed when:

  • Dementia symptoms appear within one year after movement symptoms are recognized
  • Both dementia symptoms and movement symptoms are present at the time of diagnosis
  • Movement symptoms develop within a year of dementia with Lewy bodies diagnosis

Creutzfeldt-Jakob Disease (CJD)

A degenerative neurological disease also is known as “mad cow disease,” CJD occurs in about one in one million people and has no known cure.

According to the Alzheimer’s Association, experts generally recognize three main types of CJD:

Sporadic CJD develops spontaneously for no known reason. It accounts for 85 percent of cases. On average, sporadic CJD first appears between ages 60 and 65.

Familial CJD is caused by certain changes in the chromosome 20 gene coding the biological blueprint for prion protein. People who develop familial CJD do so because they inherited the genetic changes from a parent. Familial CJD accounts for about 10 to 15 percent of cases. It develops, on average, at a younger age than sporadic CJD, with some genetic types appearing as early as ages 20 to 40.

Acquired CJD results from exposure to an external source of an abnormal prion protein. These sources estimated to account for about 1 percent of CJD cases. The two most common outside sources are:

  • Medical procedures involving instruments used in neurosurgery, growth hormone from human sources or certain transplanted human tissues.
  • Meat or other products from cattle infected with bovine spongiform encephalopathy (“mad cow disease”).

The effects of CJD effects can progress rapidly, usually over a period of several months. Symptoms can include:

  • Memory loss
  • Speech impairment
  • Confusion
  • Muscle stiffness and twitching
  • General lack of coordination (making the individual susceptible to falls)
  • Blurred vision
  • Hallucinations

Normal Pressure Hydrocephalus (NPH)

Normal Pressure Hydrocephalus is caused by an accumulation of cerebrospinal fluid in the brain’s cavities. This results in added pressure on the brain, interfering with its ability to function normally.

Most commonly affecting people in their 60s and 70s, the classic symptoms of NPH may include:

  • Difficulty walking that’s sometimes compared to the way a person walks “on a boat,” with the body bent forward, legs held wide apart and feet moving as if they’re “glued to the deck.”
  • The decline in thinking skills that include an overall slowing of thought processes, apathy, impaired planning and decision-making, reduced concentration and changes in personality and behavior.
  • Loss of bladder control, which tends to appear somewhat later in the disease than difficulty walking and cognitive decline.

While there is no single test to detect NPH, not everyone who has it exhibits the symptoms and symptoms may overlap those of Alzheimer’s or other dementias, it is recommended that someone with suspected NPH undergo examination by a neurologist with extensive experience in brain disorders. If diagnosed, doctors may install a shunt into the brain to drain excess spinal fluid.

While most people suspected of having NPH do not improve with treatment, Normal Pressure Hydrocephalus can sometimes actually be corrected. A television commercial from 2008 is still astounding in its depiction of one man’s recovery from this form of dementia.

Huntington’s Disease

A progressive brain disorder caused by a single defective human gene, Huntington’s Disease is inherited and currently incurable. At this time, treatment can only focus on managing symptoms, which generally include:

  • Uncontrolled movement of the arms, legs, head, face and upper body
  • A decline in thinking and reasoning skills, including memory, concentration, judgment, and ability to plan and organize.
  • Alterations in mood, especially depression, anxiety, and uncharacteristic anger and irritability.
  • Obsessive-compulsive behavior, leading a person to repeat the same question or activity over and over.

As there is no cure and no way to slow or stop the brain damage it causes, treatments can only focus on its managing symptoms of:

  • Chorea (involuntary movements)
  • Irritability
  • Obsessive-compulsive thoughts and behaviors
  • Anxiety
  • Depression
  • Insomnia

As a result, people with Huntington’s are encouraged to keep all their medical appointments and not to get discouraged if it takes their health care team some time to find the best drugs and the most effective doses to manage their symptoms.

Traumatic Brain Injury (TBI)

According to the Centers for Disease Control and Prevention, there are approximately 1.5 million people in the U.S. who suffer from a traumatic brain injury each year.  Of these numbers, 50,000 people die from TBI each year and 85,000 people suffer long-term disabilities.  In fact, more than 5.3 million people live with disabilities caused by TBI in the U.S.

Of these injuries, one of the major causes, particularly among seniors, is falling. Each year, according to the CDC, some 2.5 million people ages 65 and older visit the emergency department (ED) because of falls—more than any other age group.

When a TBI occurs, doctors will classify it as mild, moderate or severe, depending on whether the injury causes unconsciousness, how long that unconsciousness lasts and the severity of symptoms. While most TBIs are classified as mild as they’re not life-threatening, they can still have serious, long-term effects.

According to TraumaticBrainInjury.com, the impact of a moderate to severe TBI can impact literally dozens of different functions within the body by affecting:

  • Cognitive deficits
  • Speech and language
  • Sensory
  • Perceptual
  • Vision
  • Hearing
  • Smell
  • Taste
  • Seizures
  • Physical changes
  • Social-emotional functions

The Alzheimer’s Association notes that “Over the past 30 years, research has linked moderate and severe traumatic brain injury to a greater risk of developing Alzheimer’s disease or another type of dementia years after the original head injury.”

The research studies they cited found:

  • Older adults with a history of moderate traumatic brain injury had a 2.3 times greater risk of developing Alzheimer’s than seniors with no history of head injury, and those with a history of severe traumatic brain injury had a 4.5 times greater risk.
  • Emerging evidence suggests that individuals who have experienced repeated TBIs (concussions) or multiple blows to the head without loss of consciousness, such as professional athletes or combat veterans, are at higher risk of developing a brain condition called chronic traumatic encephalopathy (CTE)(see below).
  • Research indicates a relationship between a TBI and hallmark protein abnormalities linked to Alzheimer’s.
  • Some research suggests that traumatic brain injury may be more likely to cause dementia in individuals who have a variation of the gene for apolipoprotein E (APOE)called APOE-e4.

Chronic Traumatic Encephalopathy (CTE)

CTE has seen great interest by the media lately after forensic neurologist Bennet Ormalu, M.D., connected it to repeated concussions in football with his autopsy on Mike Webster, the Hall of Fame center for the Pittsburgh Steelers. This awareness was further heightened by the movie “Concussion,” which dramatized his discovery.

Caused by repeated blows to the head, people with CTE may not experience symptoms until years or even decades after the brain injuries occur. These may include:

  • Memory loss
  • Confusion
  • Personality changes (including depression and suicidal thoughts)
  • Erratic behavior (including aggression)
  • Problems paying attention and organizing thoughts
  • A difficulty with balance and motor skills

Because CTE is a relatively new form of dementia that has been recognized, there are no tests to determine if someone has CTE and presently no cure. If it is suspected, a thorough medical history, mental status testing, neurological exams, and brain imaging can be used to rule out other possible causes.

A definitive diagnosis can only be made through autopsy, which may show a buildup in the brain of an abnormal form of a protein called tau, which is also a hallmark of Alzheimer’s Disease.

Summary

There are over 100 forms of dementia. By knowing the cause as early as possible as you begin your journey along the gray mile, some effects can be treated, some reversed or some even cured. While no dementia diagnosis is going to make your path any easier, know that there are scientists and researchers throughout the world who are doing everything they can to help.

Tom Text

@TomJonesNBTX

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