SLHS 580: 11/6 (3) “Stages Alzherimer’s Disease”

Braak Stages I and II

Tangles in the entorhinal cortex (important for memory formation, mood, sense of smell and taste).

—> 22% of nuns had evidence (showed signs of dementia)

Braak Stages III and IV

Tangles spread to hippocampus (critical to encoding of new

information).

—> 43% of nuns had evidence (showed signs of dementia)

Braak stages V and VI

Spread to neocortex (executive fx, orientation in time, language, spatial reasoning, object/face recognition, etc)

—> 70% of nuns had evidence (showed signs of dementia)

Braak Stages

Braak stages I and II: tangles in the entorhinal cortex (important for memory formation, mood, sense of smell and taste)

• 22% of nuns had evidence of dementia

Braak stagesIII and IV: tangles spread to hippocampus (critical to encoding of new information)

• 43% of nuns had evidence of dementia

Braak stages V and VI:spread to neocortex (executive fx, orientation in time, language,spatial reasoning, object/face recognition, etc)

• 70% of nuns had evidence of dementia

What is the direct relationship between the amount of Alzheimer’s pathology in the brain and the extent of symptoms? Why?

There is no direct relationship.

—> May be due to the brain’s plasticity (the brain’s flexibility in adjusting) and ability of having more “reserve”/plasticity may compensate for pathology by establishing new connections to work around it.

Why might some individuals be able to mask symptoms of Alzheimer’s or show less severe symptoms even with similar buildup of plaques and tangles in comparison to someone showing sever symptoms?

1. Neurological Brain Reserve Hypothesis: the size and structure of the brain allows some to absorb more injury before cognitive function is affected —> large brain volume can “withstand” pathology, genetic origin

2. Behavioral/Cognitive Brain Reserve Hypothesis: complex cognitive ability increases neural plasticity and ability to “work around” pathology

Neurological Brain Reserve Hypothesis

The size and structure of the brain allows some to absorb more injury before cognitive function is affected —> large brain volume can “withstand” pathology, genetic origin

Behavioral/Cognitive Brain Reserve Hypothesis:

Complex cognitive ability increases neural plasticity and ability to “work around” pathology.

Behavioral/Cognitive Brain Reserve Hypothesis; What factors may influence cognitive functioning?

• Education

• Complex Work Environments

• Complex Language Use (Multilingualism)

• Lifelong Exercise