What is Dementia?

What is Demenita ?

 

  • Dementia is a general term that represents a group of diseases of the brain that affects thinking, memory, reasoning, personality, mood and behavior. The slow decline in mental function interferes with activities of daily living.
  • There are over 100 brain diseases that cause dementia and each form of dementia has a different cause.
  • Alzheimer’s disease is the most common form of dementia and is responsible for about 70% of dementia cases.
  • The second most common cause is vascular dementia responsible for about 10% of dementia.
  • The other causes of dementia are due to Parkinson disease, Lewy body, alcohol and multiple other causes.

Early symptoms and progression of dementia

Early symptoms and

progression of dementia

 

 

  • Forgetting things or recent events
  • Getting lost while walking or driving
  • Being confused even in familiar places
  • Losing track of time
  • Difficulty solving problems or making decisions
  • Problems following conversations and trouble finding words
  • Difficulty performing familiar tasks

 

As the disease progresses the need for help with personal care needs increases. People with dementia may not recognize family members and friends, develop difficulty in moving around and may fall, lose control of their bladder and bowel, have trouble eating and drinking and experience behavioral changes such as aggression and unpredictable behavioral disorders that are distressing to the person with dementia as well as those around them.

How is dementia diagnosed?

How is dementia diagnosed?

 

 

Diagnosing dementia involves a comprehensive evaluation that includes:

 

  1. Medical history and Physical examination:
    • Review of symptoms, including memory loss, cognitive decline and behavioral changes.
    • Medical history including past illnesses, medications and family history.
    • Physical exam to assess neurological function and overall health.
  2. Blood tests:
    • To check for underlying medical conditions that can cause cognitive decline such as thyroid disorders, vitamin deficiencies or infection.
  3. Comprehensive cognitive and neuropsychological assessment. Commonly used tests include:
    • Montreal Cognitive Assessment (MoCA) – this test assesses various cognitive domains such as attention and memory and evaluates the overall health of different brain regions involved in this cognitive test.
  4. Knowledgeable Informant Interview
    • This is a brief questionnaire that asks a family member or a caregiver about a persons cognitive abilities and the commonly used test is the AD8
  5. Screening for depression:
    • Use of the PHQ9 scale to diagnose depression. as it can mimic dementia.
  6. Brain Imaging:
    • Magnetic resonance imaging(MRI)or computed tomography(CT scan) to rule out structural abnormalities such as tumors, strokes or hydrocephalus
  7. Other considerations:
    • Ruling out potential causes of cognitive decline , such as , anxiety, depression, sleep disorders, hearing loss, etc
    • Assessing for possible drug interaction or side effect

 

Differential diagnosis of dementia:

 

Once a diagnosis of dementia is made, the next step is to determine the type of dementia. There are various types of dementia, including Alzheimer’s disease, vascular dementia and Lewy body dementia. Identifying the specific cause of dementia is essential for guiding management and treatment. Given that Alzheimer’s disease is the most common cause of dementia, this will be discussed first.

Alzheimer’s disease

Alzheimer’s disease

Dr. Alois Alzheimer was a German psychologist and neuropathologist. In 1906 Dr. Alzheimer noticed changes in the brain tissue of his patient, Augusta Deter who had died of an unusual mental illness. Her symptoms included memory loss, language problems and unpredictable behavior. After she died he examined her brain tissue under a microscope and used special stains and found clumps (now called amyloid Plaques) and tangled bundles of fibers, (now called Tau).

 

These proteins build up slowly over decades and cause previous healthy neurons to stop functioning, lose connections with other neurons and die.

 

The abnormal build up of these proteins cause changes in the brain that begins about 20-30 years before symptoms appear.

The Role of amyloid and tau protein

The Role of amyloid and tau protein

 

 

There are two proteins, called amyloid and tau proteins that cause Alzheimer’s disease.

 

Amyloid

Amyloid is a normal protein in the central nervous system. Scientists believe that people with Alzheimer’s disease overproduce B-amyloid protein or are less able to clear the protein. B-amyloid when accumulated in the neuron is dangerous and form amyloid plaques, causing the neuron to die.

Tau

Tau protein is normally in formed in neurons to maintain the cell’s structure. In Alzheimer’s tau protein becomes damaged and leaks out from the axon (part of the neuron). Tau protein clumps and forms tangles, becomes toxic, and causes the cell to die.

Diagnostic criteria for Alzheimer disease

Diagnostic criteria for Alzheimer disease

 

 

Dementia may be caused by many diseases, other than Alzheimer’s disease, and therefore clinical presentation alone is not diagnostic for Alzheimer’s disease.

 

The diagnosis of Alzheimer’s disease requires that one of three tests detect  Amyloid and Tau proteins.

 

  1. Blood biomarkers.
  2. PET brain san
  3. Biomarkers on spinal fluid (CFS)

Blood based biomarkers for Alzheimer’s diagnosis

Blood based biomarkers for Alzheimer’s diagnosis