Common Types of Dementia

Is Alzheimer’s disease a form of dementia?

Dementia is an umbrella term that encompasses several different subsets of the classification, such as Alzheimer’s disease, Lewy body dementia, or frontotemporal dementia. It may be helpful to review the most common forms of dementia and the signs and symptoms associated with each.

What is Alzheimer’s Disease?

Alzheimer’s disease is the most common form of dementia and is a widely known term among this subset of brain diseases. Often portrayed by the media as to progress rapidly from full cognitive function to sudden memory loss, in most cases there is slow disease progression from diagnosis to full loss of personal capability and functionality. Damage to the brain caused by Alzheimer’s may begin to appear a decade or so before actual memory loss or noticeable cognitive issues appear. Typically those with normal on-set Alzheimer’s begin seeing symptoms in their sixties; however, in some cases early on-set Alzheimer’s disease may cause symptoms to appear as early as age 30. For this form of Alzheimer’s disease, conversely, changes can occur rapidly over the course of 6 months to a year.

Common Symptoms of Alzheimer’s disease:

  • New information is not retained
  • Trouble recollecting recent memories
  • Problems finding words
  • Misspeaks often
  • Increased impulsivity or indecisiveness
  • Gets lost more easily
  • Irritability, uncooperativeness, or unusual combativeness
  • Sadness, fearfulness, or anxiety
  • Difficulty paying attention
  • Restlessness
  • Decreased enthusiasm
  • Reduced interest in socialization
  • Changes in coordination

What is Vascular Dementia?

One of the most notable signs of vascular dementia is a sudden change in symptoms. Individuals with vascular dementia may initially experience symptoms such as memory loss, disorientation, and etc. and then suddenly one day they wake up having trouble speaking or understanding speech. This is different than the way disease progression is experienced by people diagnosed with other dementias such as Alzheimer’s disease.

Common Symptoms of Vascular Dementia:

  • Changes in judgement and behavior
  • Spotty losses in memory
  • Shifts in emotion and energy levels
  • Confusion
  • Disorientation
  • Trouble speaking or understanding speech
  • Physical stroke symptoms, such as a headache
  • Difficulty walking
  • Poor balance
  • Numbness or paralysis on one side of the face or body

What is Lewy Body Dementia?

Lewy body dementia is estimated to be the third most common form of dementia. This type of dementia leads to a decline in thinking, reasoning, and independent muscle function. Lewy body dementia is an umbrella term that is often used to reference two related clinical diagnoses: “dementia with Lewy bodies” and “Parkinson’s disease dementia.” These disorders share the same underlying changes in the brain and very similar symptoms, but the symptoms are slightly different and appear in a different order depending on where the Lewy bodies first form. Dementia with Lewy bodies (DLB) is a type of dementia that causes problems with memory and thinking abilities that are severe enough to interfere with everyday activities. Parkinson’s disease dementia (PDD) is a term used for dementia that develops after several or many years of living with Parkinson’s, a disease that is caused by loss of dopamine-producing nerve cells.

Common Symptoms of Lewy Body Dementia:

  • Problems with movement, imbalance, frequent falls
  • Malfunctions of the “automatic” nervous system such as hands and swallowing
  • Changes in thinking and reasoning
  • Confusion and alertness that varies significantly throughout the day or from day to day
  • Delusions
  • Well-formed visual hallucinations
  • Trouble interpreting visual information
  • Sleep disturbances such as nightmares
  • Memory loss
  • Episodes of rigidity and syncope
  • Fluctuations in abilities
  • Drug responses can be extreme and strange

What is Frontotemporal Dementia?

Frontotemporal dementia, commonly referred to as FTD, is caused by a loss in nerve cells in the frontal lobes and temporal lobes. This form of dementia can cause extreme behavioral and personality changes as the areas of the brain most impacted by the disease are responsible for a person’s decision making and impulse control. This form of dementia more frequently strikes younger people and memory remains fairly intact. 

You may have heard that teenagers and young adults more commonly make poor decisions because their frontal lobes are not fully developed until age 25. Those suffering from FTD experience the same issues with decision making; however, instead of decision-making getting progressively better with age; decision making in individuals with frontotemporal dementia progressively deteriorates. People with with frontotemporal dementia are known to say things unexpectedly or appear rude at times—blurting out things that would typically remain as inside thoughts. This disease impacts a person’s impulse control related to keeping “inside thoughts” from being spoken.

Common Symptoms of Frontotemporal Dementia:

  • Loss of impulse and behavioral control
  • Trouble speaking or getting correct words out
  • Difficulty understanding others when they speak, words often sound like nonsense or made up words to them

Do you have more questions about the different forms of dementia? Ask Mimi is a resource for at home caregivers to get their questions answered. In her 20 years at St. John’s, Mimi DeVinney (our Dementia/Quality of Life Specialist) has heard dozens of questions about caring for people living with dementia.

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