Alzheimer's Disease

Question 1

What is dementia? Is it a disease?

Answer 1

Dementia is a loss of ordered neural function that impacts cognition. It is not a disease, it is a manifestation that is seen in several unrelated disorders.

Question 2

What causes Alzheimer’s disease?

Answer 2

90% of people with Alzheimer’s disease have the sporadic form which is idiopathic. The other 10% have a genetic form.

Question 3

In the genetic form of Alzheimer’s disease, what chromosomes are involved?

Answer 3

Chromosomes 1, 12, 14, 19, 21

Question 4

In the genetic form of Alzheimer’s disease, what genes are affected?

Answer 4

3 genes:

1) amyloid precursor protein (APP) gene, is on chromosome 12, if defective there will be an excessive amount of amyloid present
2) presenilin 1 (PS1) gene on chromosome 14
3) presenilin 2 (PS2) gene on chromosome 1

There is also a link between down syndrome (trisomy 21) and Alzheimer’s disease.

Question 5

Is the sensory cortex affected in Alzheimer’s disease?

Answer 5

No.

Question 6

What are the manifestations of mild stage Alzheimer’s disease?

Answer 6

• memory issues often detected/recognized by others
• careless work habits
• familiar routine, ADLs manageable

Question 7

What are the manifestations of moderate stage Alzheimer’s disease?

Answer 7

• memory is worse
• decline in cognition
• confusion
• language problems, particularly: repetitive speech and paraphasias
• some motor disturbances during ADLs (ex. trouble using fork or comb)
• indifference

Question 8

What are the manifestations of severe stage Alzheimer’s disease?

Answer 8

• severe mental impairment
• minimal voluntary movement
• unable to care for self
• bladder and bowel incontinence
• rigid, flexor posturing
• medication compliance can become an issue

Question 9

Why is diagnosing Alzheimer’s disease difficult?

Answer 9

1) no definitive test
2) clinical presentation is not definitive until later stages
3) lesions only seen microscopically post-mortem

Question 10

How long does each stage of Alzheimer’s usually last?

Answer 10

• mild stage usually can last 2-4 years from onset
• moderate stage can last 2-10 years
• severe stage normally lasts around 2 years

Question 11

What is paraphasia

Answer 11

using word in wrong context

Question 12

What happens to the brain in Alzheimer’s disease? (What is the pathology?)

Answer 12

• permanent lesions form from the accumulation of proteins
• this can cause necrosis of the neurons
• necrosis causes atrophy, shows as prominent sulci, slender gyri and enlarged ventricles
• there is also a decrease in acetylcholine

Question 13

What areas of the cerebral cortex are affected in Alzheimer’s disease?

Answer 13

• amygdala

- hippocampus

Question 14

What are the two types of lesions that develop in Alzheimer’s disease?

Answer 14

1) neuritic plaques - deposits of amyloid protein, usually at terminal ends of neurons
2) neurofibrillary tangles - accumulation of fibrous proteins in cytoplasm

Question 15

How is Alzheimer’s disease diagnosed?

Answer 15

• clinical presentation (not definitive until later stages)
• eliminate other disease that cause dementia
• look for alterations in expected areas (EEG, CT, MRI to look at cortex)
• labs to exclude other conditions (HIV, syphilis, vitamin deficiency)

Question 16

How is Alzheimer’s disease treated? Can it be cured?

Answer 16

• no cure but can slow progression
• treat symptoms
• manipulate behaviour and environment to make things easier and safer
• glutamate receptor blockers (blocks the NT glutamate which is toxic in high levels… ex. is Memantine)
• acetylcholine-esterase inhibitors (to increase Ach levels, ex. Aricept)
• low-dose antipsychotics (ex. Risperidone)
• anti-anxiety or anti-depression drugs (ex. effexor)
• statins? (to lower cholesterol)
• ASA?