L16 - Dementia Syndromes Flashcards
1
Q
How do we define dementia?
A
- Decline of memory and(or) other cognitive abilities from a previous level of function, which must be sufficiently severe to cause impairment in occupational or social functioning.
- Change from a previous level of functioning, usually progressive
- Multiple cognitive/behavioural domains affected - not just one area
- Impacts on the person’s activities of daily living (ADL)
2
Q
What are the cognitive domains?
A
Can have deficits in one and not the others, depends on area of the brain being affected
- Memory
- type: episodic, semantic, procedural
- process: encoding, recall, recognition of previously encountered information
- Language
- comprehension and expression
- knowledge of grammatical rules
- naming objects and concepts
- reading and spelling
- Visuo-perceptual skills
- recognition of objects and faces
- spatial orientation
- construction, drawing
- Praxis
- planning and executing skilled actions
- tool use
- dressing
- Attention
- filtering relevant from irrelevant information
- manipulating information held in memory
- speed of processing
- sustaining mental effort
- spatial attention
- Executive functions (have broader effects on other domains)
- organising information and behaviour
- planning - problems in this could impact other domains
- mental flexibility
- abstract thought
- impulse control and drive/initiation
3
Q
How do we map cognition in the brain?
A
- Executive functions - frontal lobe
- Parietal lobe - Visual praxis
- Occipital - object recognition areas
- Sylvian fissure - where language impairments may occur
4
Q
What are the different types of dementia syndromes?
A
- 70% Alzheimer’s
- 17% Vascular Dementia
- 13% other dementia
5
Q
How prevalent is Alzheimer’s?
A
Most prevalent, with estimates of
- 1/1000 of 40-65 year olds
- 1/50 of 65-70 year olds
- 1/20 of 70-80 year olds
- 1/5 of over 80s
(figures from the Alzheimer’s Society of Great Britain)
- “a disease of old age” - increases with age
- Disease progression – approx. 8-10 years from first symptoms to death
- certain subtypes may progress more rapidly
- usually earlier onset tends to have more rapid progression
6
Q
What is Alzheimer’s?
A
- First described by Alois Alzheimer in 1906 and by Kraepelin in 1910, who identified the beta-amyloid plaques and neurofibrillary tangles (interfere with communication between neurons)
- Pathologically-defined entity
- Both thought they were describing an unusual type of dementia different from the “senile” dementia of old age, but this proved wrong
7
Q
What is the typical presentation and progression of Alzheimer’s?
A
- Presentation is after age 60
- Memory impairment often the first presenting complaint and the most prominent
- On testing, there is both a failure to encode information and to store this information in a more permanent way (i.e., delayed recall is very poor and cueing doesn’t help retrieval)
- As disease advances, language, visuo-spatial, executive functions become compromised
- General demeanour and personality usually preserved until late in the disease
- Distribution of neurofibrillary tangles and amyloid plaques
most severe atrophy or hypometabolism is in the mesial temporal lobe (including hippocampus), parietal lobes and dorsolateral prefrontal cortex
8
Q
What is fronto-temporal lobar degeneration (Fronto-temporal dementia)?
A
- First described by Arnold Pick in 1892 and called Pick’s Disease for a long time.
- Disease concentrated in frontal and temporal lobes (anterior and lateral)
- Different pathology: Pick bodies (different to amyloid)
- Big atrophy in frontal lobe below - advanced case of disease
- Coloured areas show greatest atrophy
- Second most common cortical dementia, although still fairly rare
- ~2-10 in 10,000
- Earlier onset – 40’s or 50’s
- Large clinico-pathological samples studied in Manchester (Neary and Snowden’s group) and in Lund (Brun’s group) in the 1980’s and 1990’s
- Lund-Manchester criteria for FTD (Lund and Manchester groups. Consensus on clinical and neuropathological criteria for fronto-temporal dementia. Journal of Neurology, Neurosurgery and Psychiatry, 1994; 4: 416-8.)
9
Q
Types of FTD (depends where it starts)
What is the behavioural variant?
A
- Frontal lobe atrophy
- Personality and behaviour change (can create a caring burden)
- disinhibition, perseveration - can be inappropriate
- apathy
- emotional blunting
- over-eating, hyperorality
- executive dysfunction on neuropsych testing
- mental inflexibility
- concrete thinking
- planning problems
- memory and visuo-perceptual skills relatively spared
10
Q
Types of FTD (depends where it starts)
What is progressive non-fluent aphasia in FT dementia?
A
- Inferior frontal atrophy (around Broca’s area)
- Non-fluent speech
- Agrammatic, don’t understand syntax
11
Q
Types of FTD (depends where it starts)
What is semantic dementia? (cortical)
A
- Anterior-lateral temporal lobe atrophy (more commonly left)
- Progressive loss of semantic knowledge
- Visuo-perceptual skills preserved
- Memory (relatively well) preserved
- Personality preserved
12
Q
What is vascular (multi-infract) dementia?
A
- Second most common cause of dementia after Alzheimer’s disease
- (~2/3 of non-Alzheimer cases)
- Range: 0.2% in 65-70 year olds, 16% in over 80’s
- Caused by hypertension leading to multiple strokes in the brain
- Depends where these strokes occur
- Onset of symptoms usually related to cerebro-vascular events
- Progression more step-wise with periods of plateau
- Distribution of lesions varies widely and so could the neuropsychological picture
- many small vessel infarctions in the white matter
- Causes strokes in white matter in brain that impacts communication = impacts cognition
- could also involve major strokes
- many small vessel infarctions in the white matter
- A more “subcortical” neuropsychological picture
- slow speed of processing
- attention problems
- memory problems can be secondary to:− attention difficulties− difficulties initiating memory search
- motor and other neurological problems can be present
13
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