L43. Memory Defects

Question 1

What is the difference between subjective memory loss and objective assesment?

Answer 1

• Subjective memory loss is a personal assessment of one’s one memory and it is often a very critical one (majory of people feel they don’t have good or have a fleeting memory
• Objective memory loss is often due to memory deficits.

It is important to distinguish between two but also to remember that subject complaint may pre-date formal deficits in some cases of dementia

Question 2

Describe the famous case of HM

Answer 2

HM was a sufferer of severe epilepsy that was resistant to treatments and had severe negative impacts on his life.

He had a biltaral medial temporal lobe resection to fix the problem. The surgery was successful in reducing seizure frequency but he suffered from severe amnesia problems

Question 3

Describe the difference between retrograde and anterograde amnesia

Answer 3

• Retrograde amnesia is the inability to rember things that have happened in the past
• Anteriograde amnesia is the inability to form new memories from the time of the procedure/trauma forwards

Question 4

Is it possible to loss all memory at once?

Answer 4

Memories are all over the cortex and subcortex thus you can’t really lose all of your memory in one go

Question 5

Define Short term memory

Answer 5

It holds a small amount of information (typically around 7 items or even less) in mind in an active, readily-available state for a short period of time (typically from 10 to 15 seconds, or sometimes up to a minute).

(it is dinguished from working memory as it does not entail the manipulation or organization of material held)

Question 6

Define working memory

Answer 6

Working memory is the system that is responsible for the transient holding and processing of new and already stored information, an important process for reasoning, comprehension, learning and memory updating

Question 7

Describe long term memory?

Answer 7

Long term memory is the storage of information over minutes, hours, years for later retrieval

Question 8

What is non-declarative memory?

Answer 8

A type of long-term memory that doesn’t require conscious thought. It allows you to do things by rote.

It includes

• Skills and habits
• Priming
• Classical conditioning

Question 9

What is procedural memory?

Answer 9

Another type of long term memory

Also called implicit memory

• It is skill acquisition, it is the type of implicit memory that enables us to carry out commonly learned tasks without consciously thinking about them

Question 10

What is declarative memory?

Answer 10

Also called explicit memory (conscious). The ability to put memories you learn from day to day into context and to process them. It is the common form of memory

Question 11

Episodic memory/autobiographical memory

Answer 11

• Events in the personal context
• It is a unique and personal episode
• It is the association between a personal event and a specific temporal, spatial and emotional context

Question 12

What is semantic memory?

Answer 12

Remembering general facts and general knowledge.

It is shared knowledge and is not contextual

Includes the general meaning of words

Question 13

What system is the most crucial to memory? Where does it sit?

Answer 13

The hippocampal system which sits in the medial temporal region of the brain

Question 14

What other structures are heavily involved in memory?

Answer 14

The limbic system (entorhinal cortex)

Most memory is subcortical

• Thalamus
• Mammilary Bodies
• Basal ganglia

Question 15

Describe the lateralisation of function in terms of memory

Answer 15

The left hippocampus has a dominant role of verbal memory:

• List learning
• Paired associate learning
• Story recall

The right hippocampus has a dominant role in non-verbal memory

• Visuo-spatial associations
• Face recall

Question 16

What are some degenerative disorder causes of memory impairment?

Answer 16

• Alzheimer’s (primary dementia)
• Chronic alcoholism (secondary dementia)

Question 17

What are some cerebovascular disorder causes of memory impairment?

Answer 17

• Bilateral thalamic infarction (thalamus is very important to memory)
• Cardiogenic cerebral anoxia (the hippocampus is very susceptible to lack of oxygen)

Question 18

What are some paroxysmal/transient disorder causes of memory impairment?

Answer 18

• Transient global amnesia
• Temporal lobe epilepsy
• Post-traumatic amnesia

Question 19

Describe the neuropathology of temporal lobe epilepsy

Answer 19

• The hippocampus (in the temporal lobe) is quite epileptogenic
• Hippocampa sclerosis is a leading cause of complex seizures (gliosis and scar tissue)
• Hippocampal resection is a very successful treatment for seizures with little to no cognitive and memory defects, this is because the sclerosed hippocampus is unlikely to be functionally properly)

Question 20

Describe transient global amnesia

Answer 20

• These are transient, but striking anterograde amnesia
• Precipitating events include: sexual intercourse, immersion in cold water, emotional stress
• No disruption to ‘self-identity’
• Underlying cause remains unknown – possibilities include vascular, migraine, epileptic event, drug effects.

Question 21

Describe post-traumatic amnesia

Answer 21

• Often occurs after a major non-penetrating head trauma as a result of acceleration/deceleration forces.
• It is a profound inability to remember new events and is linked to a range of behacioural side effects like aggregion, agitation and sleep disturbances
• Concussions are small movements
• Can last up to several months

Question 22

Describe Alzheimer’s Disease

Answer 22

• The most common cause of dementia
• Age is a major risk factor
• Slow insidious onset
• Memory is not the only thing to be impacted
• No treatments

Question 23

What is a mild cognitive impairment (MCI)?

Answer 23

It is a subclinical impairment that involves a number of criteria:

• Self reported (subjective) memory complaint lasting 6-12 months
• Mild objective memory impairment
• Unaffected general cognitive function
• Normal capacity to perform ADLs

Question 24

How is mild cognitive impairment related to Alzheimer’s Disease?

Answer 24

It may be a transitional phase between normal aging and dementia

People with questionable dementia (MCI) may have higher risks of developing Alzheimer’s

Question 25

What is the risk of developing Alzheimer's Disease for patients who are diagnosed with MCI?

Answer 25

10-15% of those people will develop Alzheimer's disease per year

Question 26

What is the Braak and Braak staging of Alzheimer's Disease?

Answer 26

**Stage** **Neurofibrillary change in:** **Symptoms** I-II transentorhinal “asymptomatic” III-IV limbic system (entorhinal cortex) “incipient” V-VI neocortical association cortex “fully developed AD”

Question 27

Describe the impact of Alzheimer's disease on language

Answer 27

People with AD often get associated deficits as it moves out of the limbic system to surronding areas. They get prominant **dysnomia** (inability to name things) * Fluent, empty language * Paraphasic errors * Missing key information and words A Wernike's Area like aphasia