dementia Flashcards
Define dementia
Dementia, also known as major neurocognitive disorder, is a progressive decline in cognitive function affecting multiple domains including language, executive function, memory and social cognition
What are the types of dementia
- alzheimers
- lewy body
- vascular
- frontotemporal
what are some reversible causes of dementia/ differential diagnosis of dementia
- vit b12 deficiency
- subdural haemorrhage
- wernickes
- hypoglycaemia
- alcohol
What is the most common type of dementia
- Alzheimers
What is the pathology of alzheimers
- deposition of extracellular b- amyloid and intracellular tau protein lead to neurotoxcity and reduced cholinergic transmission
What are the causes of the pathology of Alzheimer?
- Decreased Aβ1–42 together with increased T-tau or P-tau in CSF
- Increased tracer retention on amyloid PET
- AD autosomal dominant mutation present (in PSEN1, PSEN2, or APP)
Pathology overlap of the dementias
- 25% of all patients with AD develop parkinsonism.
- 50% of all cases of PD develop AD-type dementia after 65 years of age (Hansen et al. 1990).
- 70% of patients with sporadic AD display Parkinson’s pathology
What the risk factors for alzheimers
- FX
- downs syndrome
- genetics
- advanced age
Clinical features of alzheimers
- Characteristic order of language impairment: naming → comprehension → fluency
- Memory impairment
Brain lesions are marked by … in alzheimers
- neurofibrillary tangles
- amyloid plaques
- neuronal loss
- brain atrophy
- with defects in acetylcholine synthesis at the cellular level
How would a patient present with alzheimers ?
- agnosia - cant recognise things
- apraxia - cant do basic motor skills
- aphasia - cant speak as well as normal
Alzheimer’s diagnosis criteria
NINCDS– ADRDA criteria -1984.
(1) the clinical diagnosis of AD could only be designated as “probable” while the patient was alive and could not be made definitively until AD confirmed at PM
(2) the clinical diagnosis of AD could be assigned only when the disease had advanced to the point of causing significant functional disability and met the threshold criterion of dementia.
What happens in the typical amnesic variant for Alzheimers disease?
Early degeneration of medial temporal lobe before degeneration spreads to temporal neocortex, frontal and parietal association areas.
What does the temporal lobe do?
- Hearing (superior temporal lobe
- Language comprehension (superior temporal lobe)
- Semantic knowledge (anterior temporal lobe)
- Memory (hippocampus)
- Emotional/affective behaviour (limbic system)
Features of Amnesic Alzeheimers
- Profound failure to create new memories
- Can’t find new home
- Can’t remember new people, names, tasks
- Events/People since operation
- Language essentially frozen in 50’s
Timeline for Amnesic variant Alzeheimers
- Selective amnesia. Semantic and language impairments > Complex attention (divided, selective, attention switching) > Visuospatial, sustained attention and executive functioning skills > Global deficits.
What is the congnitive profile of those with AD?
- Episodic memory: frequent intrusions and repetition errors, and high numbers of false positive errors in recall
- Problem with complex attention/executive function
- Aphasia
- Cant remember new things
Visual variant of Alzeheimers
- Posterior occipitoparietal, occipitotemporal or more rarely primary visual cortex
- Visual deficits, dyspraxia, dysgraphia,simultanagnosia -> global
- Not common