Progressive Verses Static Dementia | Focal or Global | Categories of Potentially Reversible Dementia |
Characteristics Unique to Frontotemporal Dementia | Typical Order of Symptom Presentation

Dementia:

Dementia - an acquired, persistent, or irreversible reduction in intellectual functioning that occurs after the brain has matured (around 15 years of age).
Manifestations:

  1. language (aphasia)
  2. memory (amnesia)
  3. orientation
  4. motor skills (apraxia)
  5. visuospatial skills
  6. cognition (e.g., abstraction, reasoning, attention).
  7. loss of perception (agnosia)
  8. poor judgment and impulse control
  9. changes in emotion or personality
  10. loss of ability to recognize memory loss (anosognosia)
  11. loss of organizational and planning abilities
  12. loss of ability to concentrate, disorientation, and apathy

    These impairments must be to the degree to interfere with daily social or occupational functioning. Most memory disorders fall under the general heading of dementia.

Dementia Is a Matter of Severity:

Dementia ranges in severity from marginal to severe cognitive compromise (Petersen et al. 1999). For a dementia to be diagnosed, it must impair your day-to-day functioning. This level of impairment is characteristic of deterioration of previously acquired intellectual abilities of sufficient severity to interfere with social or occupational functioning and to impair [one’s] capacity to meet the ordinary demands of living” (Campbell 1989). There are more than sixty forms of dementia, and the type is usually identified by the cause (Haase 1977). For a dementia to be present it must render you or be capable of rendering you incapable of independent functioning.

Categories of Dementia:

Dementia can be broken down into four categories. These include:

  • amnestic disorders
  • cognitive disorders
  • attention disorders
  • motivation disorders

Amnesia:

Amnesia is the medical term associated with forgetting. Memory loss is the most common problem associated with dementia, but not all dementias have memory loss as part of their initial or overall progression. Memory loss is closely associated with structural changes in the basal forebrain and the temporal lobes in the brain (see appendix D for help with terms). These areas are responsible for the production of the neurotransmitter acetylcholine. There are two types of amnesia: anterograde amnesia is the inability to remember new information and is usually the first type of amnesia seen in progressive dementias; retrograde amnesia is the inability to recall old memories from long-term memory.

Cognitive Disorders:

Cognitive disorders are essentially a loss of knowledge and are usually the result of damage to the temporal and/or parietal lobes of either the right or left hemispheres. Cognitive disorders include: language impairment, reading and writing impairment, loss of math skills, inability to draw, loss of ability to use objects, getting lost, and loss of the ability to recognize familiar faces or things.

Attention Disorders:

In attention disorders (often seen in delirium) people are unable to sustain their attention long enough to complete a task and are easily distracted. This type of disorder is often acute, with a sudden onset. It is often the result of an infection, abnormal pressure on the brain, or a reaction to medications. Attention disorders are often reversible with treatment.

Motivation Disorders:

Motivation disorders are exhibited by a severe lack of motivation. Patients often lose interest in doing things to the point of not taking care of themselves or not being able to express emotions. These behaviors are often related to depression or to abnormalities in the frontal lobes or major relay centers within the brain, such as the basal ganglia or thalamus.

Progressive Verses Static Dementia:

Dementia can be divided into two broad classifications: progressive and static. Progressive dementias are related to an ongoing disease process such as Alzheimer’s disease and tend to get progressively worse. Static dementias are usually associated with an injury, stroke, or some reversible condition such as a vitamin deficiency. Static dementias tend to remain the same if no other injury or medical complication occurs.Most dementias are progressive and usually involve a gradual change in baseline functioning that takes place over months to years. If the progression of symptoms takes place in a matter of days or weeks, it’s probably delirium (Kaye 1998). Progressive dementias involve progressive neuronal dysfunction and loss of neurons in certain areas of the brain (Cummings et al. 1998). Although specific areas of the brain can be identified as being structurally affected by a progressive dementia, symptoms such as memory loss and behavioral change are usually more global in nature. Shortly we will review some of the specific types of dementia that fall under the general heading of progressive dementias.

Dementia Can Be Focal or Global:

Dementias can also be focal (localized) or global. In focal dementias, the cause of the problems and the symptoms are limited to specific areas of the brain (such as the damage done by a single stroke). In global dementias, the problem cluster and damage are located in several areas within the brain. Many dementias affect frontal lobe functions involving judgment, social conduct, and behavioral inhibition.

Reversible Causes of Dementia:

The prevalence of potentially reversible dementia is around 20 percent (Freter et al. 1998). There are many causes of dementia that are reversible. If a dementia is suspected, these potential causes should always be ruled out:

  • Vitamin B1 (thiamin), deficiency (often caused by alcohol abuse)
  • Liver or kidney failure
  • Thyroid gland malfunction
  • Normal pressure hydrocephalus
  • Medication reactions
  • Vitamin B12 deficiency
  • Hypercalcemia
  • Hyper- or hypoglycemia
  • TumorsSalt or water imbalance (Hyper and hypoatremia)
  • Depression/anxietyInfectionsLyme disease
  • Herpes simplex
  • Cryptococcus InfectionSyphilisHeart and lung disease
  • Exposure to toxins (heavy metals, carbon monoxide, etc.)
  • Infections of the CNS.
  • Communication problems (poor vision, hearing, etc.)

Categories of Potentially Reversible Dementia (Sabiston 1997):

  • Drugs and alcohol toxicity
  • Ear and eye problems
  • Metabolic and endocrine abnormalities
  • Emotional problems
  • Nutritional deficiencies
  • Traumas or tumors
  • Infection processes
  • Atherosclerotic complications

Cortical Verses Subcortical Dementias:

Dementias can be roughly broken down into two types depending on where in the brain degeneration is initially seen. These include cortical and subcortical disease processes. They are referred to as cortical dementias because they initially affect the outer layers of the brain (cortical). This classification of disorders is often marked by deterioration in memory, language, and disturbances in motor functions and perception. Areas of the brain affected with cortical dementias include the medial temporal lobes and the association cortices in the temporal, parietal, and frontal lobes.The second type of dementia involves deterioration of the subcortical portions of the brain. These are disorders such as Parkinson’s disease, Binswanger’s disease, normal pressure hydrocephalus, Huntington’s disease, and supranuclear palsy, among others. Subcortical dementias are marked by the initial deterioration of the deeper structures of the brain (subcortical) and are often first detected by motor abnormalities.There are often milder memory deficits, slowed information processing, more intact language functions, impairments in executive functioning (decision making and quick thinking), motor slowing, and changes in behavior and mood

Deterioration that involves cortical structures within the brain include Alzheimer’s Disease and or frontotemporal dementia.
These are referred to as cortical dementias because they initially affect the outer layers of the brain (cortical). 
Marked by:

  1. Deterioration of Memory
  2. Language deterioration
  3. Disturbances in motor functions
  4. Perceptual disturbances

Affects:

  1. Medial temporal lobes
  2. Association cortices in the temporal, parietal and frontal lobes

Initially affect the brain stem, midbrain, diencephalons and basal ganglia.  Include Parkinson’s disease, Binswanger’s disease, normal pressure hydrocephalus, Huntington’s disease, and supranuclear palsy.
Marked by:

  • Milder memory deficits
  • Slowed information processing
  • More intact language functions
  • Impairments in Executive functioning (decision making and quick thinking)
  • Motor slowing
  • Changes in behavior and mood

Typical Order of Symptom Presentation:

Frontotemporal dementia usually presents with deficits in social grace, judgment, and appropriate behavior or language that are inproportional to memory deficits and usually present prior to the onset of more severe memory problems. Noted deficits are often coupled with preoccupations with bodily functions, depression, anxiety, and delusions (Kaye 1998). The disease often ends in a terminal vegetative state. Recent memory, visuospatial skills, and mathematical skills may remain relatively intact, which is a clear distinction from Alzheimer’s disease (Welsh-Bohmer and Ogrocki 1998).

Copyright © 2003 - 2006, The Memory Doctor, LLC. All Rights Reserved.