Alzheimer's Disease

Question 1

Discovery

Answer 1

by Alzheimer in 1906

Question 2

Morbidity rate

Answer 2

~60% of dementia cases

affects usually the elderly

Question 3

Disease characteristics

Answer 3

progressive and terminal

Question 4

Symptoms (8)

Answer 4

1) memory impairments, especially declarative memory
2) with progression of the disease impairments in familiar face recognition
3) early symptoms include difficulties in finding words and names
4) later symptoms include comprehension problems and fluent conversation outputs
5) visual-spatial problems
6) general decline of intelligence and cognitive functioning
7) difficulty in executive functioning (e.g. preservation of thought, problem-solving)
8) mood and personality disorders, e.g. paranoia or depression

Question 5

Gross anatomical changes (5)

Answer 5

1) overall shrinkage of the brain
2) widening of the sulci
3) shrinkage of the gyri
4) enlarged ventricles
5) cell degeneration or death

Question 6

Plaques

Answer 6

• extracellular
• clumps of long beta-amyloid chains at the synopses
• prevent communication and the transport of nutrients

Question 7

beta-amyloid changes compared to controls

Answer 7

Control: 95% short chains, 5% long chains

Alzheimer’s Disease: 60% short chains, 40% long chains

Question 8

Neurofibrillary tangles

Answer 8

• intracellular
• composed of broken-up Tau proteins
• break up structure and the transport of nutrients within the cell
• results in loss of neural activity and general cortical atrophy

Question 9

Causes?

Answer 9

• largely unknown
• some genetic links
• environmental factors, like brain injury or toxins
• low education (only correlated!!!)
• neurochemical features: the spread of AD through the brain follows the path of Acetylcholine

Question 10

Genetic links details

Answer 10

chromosome 21 (encodes amyloid)
chromosome 19 is linked with apolipoprotein E4 (ApoE4), which if inherited by both parents increases risk of AD

Question 11

Neurochemical features details

- the Acetylcholine hypothesis

Answer 11

• AD causes a loss of 70% of choline acetyltransferase (enzyme that synthesises Ach)
• Ach agonists aid memory
• inhibitor of acetylcholinesterase (enzyme that breaks down Ach) is sometimes successful

Question 12

General problems of drug treatment of AD

Answer 12

1) most drugs don’t cross the blood brain barrier and have side effects in the rest of the body
2) treatment with Ach only has varying success