Brain and behaviour session 8: other dementias
Dementia = any progressive, degenerative disease affecting the brain
Vascular dementia
Focal dementias
Subcortical dementias
Frequency of other dementias
Alzheimer's disease: 62%
Vascular dementia: 17%
Mixed dementia (i.e., AD + vascular): 10%
Lewy-body dementia: 4%
Frontotemporal dementia: 2%
Parkinson's dementia: 2%
Other: 3%
Vascular (multi-infarct) dementia
Second most common cause of dementia in UK and Europe; commonest cause in
some parts of Asia (e.g., 50% in Japan).
Loss of cognitive functioning due to disruption of blood supply to the brain, e.g., a
series of small ‘strokes’.
Stroke = disruption to the supply of blood to the brain caused by: blocked artery (e.g.
a blood clot: thrombosis) or bleed into the brain from a burst artery (haemorrhage)
Blocked arteries are the most common cause of vascular dementia.
Strokes deprive the brain of oxygen and nutrients. Cells die, leading to areas of cell
loss (‘lesions’ or ‘infarcts’).
Each small stroke causes a further deterioration.
Many patients have a history of hypertension (high blood pressure).
Other risk factors include smoking, diabetes and high cholesterol.
Symptoms can appear suddenly (e.g., after a mini-stroke) and then show “stepped”
progression.
Progression can be slowed by improving cardiovascular function
Yet prognosis is not good: 5 year survival rate < 40%
Patients have ‘patchy’ deficits that vary case to case, depending on the area(s)
affected. Some brain areas are more vulnerable to stroke because they receive
supply from a single artery.
Frontal lobes seem particularly prone:
Problems with concentration and acute confusion
Problems with organising complex thought and behaviour
Behavioural symptoms: apathy, restlessness
NB Apathy at early stage in vascular dementia (later stage in AD)
Physical weakness/paralysis (symptoms associated with frontal stroke)
Vascular dementia
Margaret Thatcher (1923 - 2013) Conservative MP from 1959. Prime Minister 1979-
1990.
Series of small strokes since 2002.
Daughter, Carol Thatcher, wrote in 2008 how she
first noticed problems in 2000, when Mrs T. was in her mid 70s: “Mum started
asking the same questions over and over again, unaware she was doing so”. Has to
, be reminded that her husband, Denis, is dead. “’Were we all there?’, she’d ask
softly”
Focal dementias
In Alzheimer’s, pathology and atrophy is widespread, affecting temporal, parietal
and frontal lobes.
In focal atrophy, damage is restricted to limited parts of the cortex before eventually
becoming more widespread.
Frontotemporal dementia
1. Frontal-variant (fvFTD) effect frontal lobes
2. Semantic dementia (SD) effect the anterior temporal lobes
3. Posterior cortical atrophy (PCA) effects the parietal and occipital lobes
Frontotemporal Dementia
Rare overall but more common in younger people; typically diagnosed between 45
and 65 years of age
Different pathology from AD – No amyloid plaques or neurofibrillary tangles.
Sometimes there are “Pick bodies” inside cells (clumps of tau protein).
Different forms of FTD, depending on where the atrophy is:
Frontal variant (in 70% of cases): atrophy in frontal lobes
Semantic dementia: Atrophy in anterior temporal lobes
Often a mixture of symptoms; start out different but become similar over time
Characteristic “knife-edge” atrophy
Frontal variant FTD
Frontal degeneration in frontotemporal dementia (FTD) causes:
Personality changes: rudeness, apathy, impatience.
Lack of inhibition; inappropriate language and behaviour.
Loss of empathy.
Compulsive/ritualised behaviour – obsessions with time/numbers; hoarding.
Overeating; preference for sweet foods.
Semantic Dementia (Temporal variant FTD)
Atrophy restricted to anterior temporal lobes bilaterally
Hippocampus survives – damage is only to semantic memory unlike that of
Alzheimer’s
Semantic Dementia: Specific semantic deficits
Progressive loss of conceptual knowledge, accessed from both words and pictures
1. Good language skills
2. Good memory for recent events (episodic memory)
3. Intact non-verbal reasoning
These skills are impaired in Alzheimer’s
Picture Naming in SD – is able to understand the main concept but is unable to
distinguish between differences within the same category (calling specific birds by
same name or other animals)
Picture Copying – where there is a delay and memory is needed to draw an image
specific features will be lost
Posterior cortical atrophy (PCA) = focal, Alzheimer- like pathology affecting posterior
parietal cortex.
Symptoms:
Dementia = any progressive, degenerative disease affecting the brain
Vascular dementia
Focal dementias
Subcortical dementias
Frequency of other dementias
Alzheimer's disease: 62%
Vascular dementia: 17%
Mixed dementia (i.e., AD + vascular): 10%
Lewy-body dementia: 4%
Frontotemporal dementia: 2%
Parkinson's dementia: 2%
Other: 3%
Vascular (multi-infarct) dementia
Second most common cause of dementia in UK and Europe; commonest cause in
some parts of Asia (e.g., 50% in Japan).
Loss of cognitive functioning due to disruption of blood supply to the brain, e.g., a
series of small ‘strokes’.
Stroke = disruption to the supply of blood to the brain caused by: blocked artery (e.g.
a blood clot: thrombosis) or bleed into the brain from a burst artery (haemorrhage)
Blocked arteries are the most common cause of vascular dementia.
Strokes deprive the brain of oxygen and nutrients. Cells die, leading to areas of cell
loss (‘lesions’ or ‘infarcts’).
Each small stroke causes a further deterioration.
Many patients have a history of hypertension (high blood pressure).
Other risk factors include smoking, diabetes and high cholesterol.
Symptoms can appear suddenly (e.g., after a mini-stroke) and then show “stepped”
progression.
Progression can be slowed by improving cardiovascular function
Yet prognosis is not good: 5 year survival rate < 40%
Patients have ‘patchy’ deficits that vary case to case, depending on the area(s)
affected. Some brain areas are more vulnerable to stroke because they receive
supply from a single artery.
Frontal lobes seem particularly prone:
Problems with concentration and acute confusion
Problems with organising complex thought and behaviour
Behavioural symptoms: apathy, restlessness
NB Apathy at early stage in vascular dementia (later stage in AD)
Physical weakness/paralysis (symptoms associated with frontal stroke)
Vascular dementia
Margaret Thatcher (1923 - 2013) Conservative MP from 1959. Prime Minister 1979-
1990.
Series of small strokes since 2002.
Daughter, Carol Thatcher, wrote in 2008 how she
first noticed problems in 2000, when Mrs T. was in her mid 70s: “Mum started
asking the same questions over and over again, unaware she was doing so”. Has to
, be reminded that her husband, Denis, is dead. “’Were we all there?’, she’d ask
softly”
Focal dementias
In Alzheimer’s, pathology and atrophy is widespread, affecting temporal, parietal
and frontal lobes.
In focal atrophy, damage is restricted to limited parts of the cortex before eventually
becoming more widespread.
Frontotemporal dementia
1. Frontal-variant (fvFTD) effect frontal lobes
2. Semantic dementia (SD) effect the anterior temporal lobes
3. Posterior cortical atrophy (PCA) effects the parietal and occipital lobes
Frontotemporal Dementia
Rare overall but more common in younger people; typically diagnosed between 45
and 65 years of age
Different pathology from AD – No amyloid plaques or neurofibrillary tangles.
Sometimes there are “Pick bodies” inside cells (clumps of tau protein).
Different forms of FTD, depending on where the atrophy is:
Frontal variant (in 70% of cases): atrophy in frontal lobes
Semantic dementia: Atrophy in anterior temporal lobes
Often a mixture of symptoms; start out different but become similar over time
Characteristic “knife-edge” atrophy
Frontal variant FTD
Frontal degeneration in frontotemporal dementia (FTD) causes:
Personality changes: rudeness, apathy, impatience.
Lack of inhibition; inappropriate language and behaviour.
Loss of empathy.
Compulsive/ritualised behaviour – obsessions with time/numbers; hoarding.
Overeating; preference for sweet foods.
Semantic Dementia (Temporal variant FTD)
Atrophy restricted to anterior temporal lobes bilaterally
Hippocampus survives – damage is only to semantic memory unlike that of
Alzheimer’s
Semantic Dementia: Specific semantic deficits
Progressive loss of conceptual knowledge, accessed from both words and pictures
1. Good language skills
2. Good memory for recent events (episodic memory)
3. Intact non-verbal reasoning
These skills are impaired in Alzheimer’s
Picture Naming in SD – is able to understand the main concept but is unable to
distinguish between differences within the same category (calling specific birds by
same name or other animals)
Picture Copying – where there is a delay and memory is needed to draw an image
specific features will be lost
Posterior cortical atrophy (PCA) = focal, Alzheimer- like pathology affecting posterior
parietal cortex.
Symptoms:
