Week 6: Dementia Flashcards
Is dementia a specific disease?
No, it is not a specific disease but rather an overall term that describes a wide range of symptoms associated with declines in memory or other cognitive skills that reduce everyday abilities
What are progressive dementias?
They are characterised by a continual decline in functioning overtime
What categories of dementia are considered to be progressive?
Cortical dementias
Subcortical dementias
Mixed dementias
Examples of cortical dementias?
AD
Picks disease
Frontal lobe dementia
Examples of subcortical dementias?
Huntingtons disease
Parkinsons disease
Examples of mixed dementias?
Lewy body dementia
Multi-infarct (vascular) dementia
What are potentially static dementias?
These dementias are not progressive
What categories of dementia are considered to be potentially static?
Toxic conditions - heavy metal poisoning
Infectious conditions - herpes encephalitis
Miscellaneous - tumour, trauma
What are some potentially reversible dementias?
Systematic illnesses - amnesia
Deficiency states - vit b12
Endocrine disorder - addisons disease, thyroid disorders
Drug toxicity - antipsychotics
What is an example of psuedodementia?
Depression
What is the most prevalent dementia?
Alzheimers disease
Who diagnoses dementia?
Geriatrician, neurologist or medical practitioner
Whos opinion is essential for dementia diagnosis?
Clinical neuropsychologists
Why is early diagnosis important for every case?
Provided with a diagnostic answer and possible education for the patient and family to relieve fear
Why is early diagnosis important for static dementia?
You can then treat the underlying disease and initiate prevention and rehabilitation strategies
Relieve the patients fear of an irreversible disease
Why is early diagnosis important for progressive dementia?
You can begin to treat behavioural and cognitive symptoms (eg. memory strategies)
Can also make legal and financial plans while the patient is still competent
What is dementia labelled in the DSM-5?
Neurocognitive disorder (NCD)
- much broader classification
Diagnostic criteria for NCD?
Evidence of significant cognitive decline from a previous level of performance
- Has to be notable by others
- Need testing to assess
Deficits interfere with independence in everyday life
The deficits do not occur exclusively in the context of a delirium
The deficits are not better explained by another mental disorder
When diagnosing someone with MND, you need to…
- Specify what type/cause
- Specify the extent of behavioral disturbances
- specify severity
Cortical to subcortical dementia?
Cortical dementia is characterized by preferential neuronal loss to the cortical regions of the brain
This can progress and start to affect subcortical regions of the brain (later stages of the disease)
Why is there a lot more deficits in movement with subcortical dementia?
Involves areas important for movement such as the basal ganglia
E.g. Parkinsons dementia is dementia of the subcortical type
What is the strongest predictor for AD?
Age - incidence increases with age
Are there any gender differences in AD?
Twice as many women as men
What is the average duration of AD?
8-10 years
Those with AD rarely survive more than 15 years post-diagnosis
Why may AD symptoms not be noticed until later on?
May not know because the brain is so good at using cognitive reserves to compensate for loses - however it gets to a point where you just can’t compensate anymore
Sporadic vs. familial AD?
Sporadic: most common type, not a strong genetic basis (APOE34 gene) - typical onset after 80 years
Familial: rare - but strong genetic trait
Early onset dementia - after 50 years
Where does cell loss occur in AD?
Cortical grey matter of the brain and limbic structures (hippocampus, amygdala)
Which lobes are the most atrophied in AD?
Frontal, temporal and parietal
How many cells are lost in affected lobes (AD)? and why?
Estimated 50% of large neurons in these areas
Due to a loss of dendritic arborisation (decreases and declines in dendritic branching that allows the brain to form connections)
Cortical thinning results in….
Ventricular enlargement
What are the primary markers of AD brains?
Amyloid/senile plaques
Neurofibrillary tangles
What are amyloid/senile plaques?
Clump like deposits, round aggregates of cellular trash
Made of b-amyloid protein and apolipoprotein (ApoE)
Toxic to neurons
What are neurofibrillary tangles?
Resemble entwined and twisted pairs of rope within the cytoplasm of swollen cell bodies
Made of the protein tau
Where are senile plaques typically found?
Frontal and temporal regions of the brain
Hippocampal complex
Where are neurofibrillary tangles found?
All throughout the brian but concentrated in temporal-parietal areas as well as the hippocampal complex
Much of AD pathology begins in the….
temporal regions
Onset symptoms of AD?
Failing recent memory
Depression and irritability
Occasionally a seizure (when neurons are dying it can trigger a miscommunication in the brain)
One or more language problems
Disorientation and confusion when sudden disruption to work or social life occurs (struggles with forming new association in new environment)
Cognitive functions affected in AD are…
Memory - long term declarative, anterograde amnesia, STM
Attention - 7+/-2 may become less
Slowed information processing
Abstract reasoning
Language
Visuospatial skills
Fluent aphasia becomes prominent - non-words and incorrect words
Speech in AD progression?
Naming difficulties Dysfluency Bizarre word combinations Non-fluent, repetitive and non-communicative speech becomes apparent May have partial or complete mutism
What may reemerge at the end stage of AD?
Primitive reflexes
- sucking
- grasping
Really go back to an infant state
Aside form cognitive changes, what behavioural and personality changes are associated with AD?
May cling to the caregiver, be easily distracted Be disinterested Have poor self-care Agitation and restlessness - bursts of violence and destructiveness Wandering Suspiciousness and paranoia Incontinence Depression
Which areas of the brain are affected by frontal-lobe dementia?
Frontal lobes
- significant atrophy in frontal and temporal lobes
- some changes to the parietal lobes
However, subcortical structures, as well as the cerebellum and brain stem are affected
What is frontal-lobe dementia often called?
Picks disease
What is the pathology of frontal lobe dementia?
Abnormal collections of tau protein in the brain
Deterioration of the caudate nucleus (BG - timing, ordering and sequencing movement)
Cerebellum deterioration
What happens in the initial stages of frontal-lobe dementia?
Socially disinhibited behaviour, silliness and poor judgement
Incontinence may also occur
What happens in the middle stages of frontal-lobe dementia?
Progressive apathy, blunted affect and cog dysfunction
What happens in the late stages of frontal-lobe dementia?
May become mute and display motor rigidity
How does frontal-lobe dementia end?
In a terminal vegetative state
What is the disease duration for frontal-lobe dementia?
2-17 years
What percentage of dementia does frontal-lobe dementia account for?
12%
What are some of the cognitive deficits in those with frontal-lobe dementia?
Empty speech Dysnomia - object naming difficulties Dysfluency Lack of self-awareness Executive dysfunction - frontal lobes
What is huntingtons disease?
A progressive sub-cortical dementia that is fatal
Is huntingtons prevalent?
No it is rare
Which gene is the cause of huntingtons disease?
ITI5 on chromosome 4
What age do people get symptoms of huntingtons?
30-40 years
How long following the onset of symptoms do those with huntingtons survive?
10-20 years
How likely are you to inherit huntingtons disease?
It is autosomal dominant - affecting 50% of offspring will have the trait
100% of people with the trait will go on to develop the disease = dominant
Chorea is a symptom of huntingtons. What is it?
Involuntary, spasmodic and torturous movements that become disabling
Cognitive deficits of those with huntingtons?
Disturbances to eye movements
Attention span
Memory
Speech production
Visuospatial
Cannot regulate own behaviour
Planning and organisation
What is the 2nd largest type of dementia?
Multi-infarct (vascular) dementia
What causes multi-infarct dementia?
Multiple infarctions of brain tissue from repeated strokes or blockages to blood vessels
is multi-infarct dementia cortical or subcortical?
Can be either - it depends on where the strokes are occurring
Deterioration is step wise occurring with strokes
What is an example of dementia from infection?
Creutzfeldt-Jakob disease (CJD)
What is CJD?
A rapidly Progressive sub cortical dementia affecting one person in 1 million per year = extremely rare
What is the pathology of CJD?
Results in spongiform encephalopathy (SE) - sponge like holes throughout the brain
Typically caused by infectious agent does not produce usual symptoms of acute infection
Transmitted by consuming infected meat both within and across species
Astrogliosis following death of neurons
Small, rusted, stick-like fibres - scrapie associated fibrils (SAFs)
The Karu people?
Related to CJD
They were cannibals ingesting prions which are abnormally folded proteins in the brain they ate deceased family members especially their brains in which women and children eat
Sporadic CJD?
This is the most common it occurs despite no risk factors being apparent
Variant CJD?
Like mad cow disease it is a cross species infection via consumption of tainted meat containing neural tissue
Familial CJD?
An extremely rare familial variant only found in a handful of families this results in fatal insomnia
Eg. Gerstmann-straussker-scheinker syndrome (GSSS)
Why do researchers believe it is possible for it to be years before CJD is detected
They believe it is a slow virus that incubates over years possibly in the hosts spleen it is camouflaged in cells so it is not to be recognised by the immune system
Which areas of the brain are targeted by the spongy tissue
The Cerebellum and cerebrum
Motor symptoms in CJD?
Uncoordinated
Slurred speech and inarticulate
Involuntary tremors and grimaces
Cannot swallow - may eventually die of starvation
Emotional/cognitive symptoms of CJD?
Mood disorders (depression, anxiety, hypo mania)
Fatigue
Sleep difficulties
Attention and concentration problems
Progression of CJD?
Very rapid. Typically less than a year, usually within 3-4 months
