Neuroimaging in dementia Flashcards
Describe what Dementia is.
Dementia refers to a decline in cognitive function, in which awareness of the environment is preserved.
List Manifestations of Executive Dysfunction:
Poor Planning and Problem Solving
Impulsivity
Difficulty in Task Switching
Disorganized Thought
List the clinical features of Dementia
cognitive dysfunction
Memory loss
Loss of higher cognitive processes. E.g. executive function, visuospatial ability and language.
Challenges in planning or solving problems
Changes in mood, social behaviour, emotional control and personality.
What does the frontal lobe control
Executive functions
what does the temporal lobe control
Learning and memory
What does the partial lobe control
Visuospatial functions
State frontal lobe dysfunction symptoms/ how does dementia affect the frontal lobe
Executive dysfunction
Alterations in behaviour and personality
Expressive dysphasia
State temporal lobe dysfunction symptoms/ how does dementia affect the temporal lobe
Mood changes
Episodic memory loss
Receptive dysphasia
State parietal lobe dysfunction symptoms
Visuospatial dysfunction
Dyslexia
Dyscalculla
difficulties with reading, writing, math, dyslexia and distinguishing left from right.
Why are screening tests performed for dementia?
Screening tests can be performed to assess cognitive impairment and suspected cognitive decline
List exams of cognitive tests used for dementia assessment
mini-mental state examination (MMSE)
Montreal cognitive assessment (MoCA)
Clinical Dementia Rating (CDR) scale
CLOX test
How can premorbid intelligence be measured?
using the national adult reading test (NART)
This is a measure of intellectual ability level prior to the onset of disorders
List the types of dementia
Alzheimer’s disease
Vascular dementia
Lewy body dementia
Frontotemporal dementia
List the risk factors of Alzheimer’s disease
Age, Vascular Risk Factors, Family History, APOE 4
allele status
Define Alzheimers disease
Alzheimer’s disease: characterised by the deposition of amyloid-beta plaques and tau protein tangles in the brain.
List the clinical features of AD
Depression & Anxiety, Social withdrawal, Aggression,
Wandering.
List pharmacological interventions for AD
Donepezil, a centrally acting reversible acetylcholinesterase inhibitor
(increasing acetylcholine concentrations at cholinergic synapses).
Memantine, an NMDA receptor antagonist (blocks the effects of glutamate,
reducing neuronal excitability).
List the different types of dementia
Alzheimer’s Disease (AD)
Vascular Dementia
Lewy Body Dementia (LBD)
Frontotemporal Dementia (FTD)
State the characteristics and cause of AD
Characteristics: The most common form of dementia, Alzheimer’s is characterized by the progressive loss of memory and cognitive functions.
Causes: It is associated with the accumulation of amyloid-beta plaques and tau tangles in the brain, leading to neuronal damage.
State the characteristics and cause of Vascular Dementia
Characteristics: Caused by impaired blood flow to the brain, leading to cell damage or death.
Causes: Often results from stroke, atherosclerosis, or other conditions that damage blood vessels and reduce circulation, leading to multiple infarcts in the brain.
State the characteristics and cause of Lewy Body Dementia (LBD)
Characteristics: Dementia with Lewy bodies is marked by the presence of Lewy bodies (abnormal deposits of the protein alpha-synuclein) in brain cells.
Causes: The exact cause is unknown, but genetic factors may play a role.
State the characteristics and cause of Frontotemporal Dementia (FTD)
Characteristics: Affects the frontal and temporal lobes of the brain, typically seen in a younger age group compared to other dementias.
Causes: Involves degeneration of the frontal and/or temporal lobes. Genetics play a significant role, with many cases linked to specific gene mutations.
What assessments can be performed for Frontotemporal Dementia (FTD)
MMSE
MoCA
What assessments can be performed for Vascular Dementia
MMSE
MoCA
MRI
What is a PET scan
Positron Emission Tomography
PET scans can reveal reduced metabolic activity in areas of the brain typically affected by Alzheimer’s disease and other dementias.
A radionuclide is administered into a vein through an intravenous line. The PET scanner detects the amount of the radionuclide collected in the tissue, affecting how brightly the tissue appears on the image and indicating the level of organ or tissue function.
What is a SPECT scan
Single-photon Emission Computed Tomography
Vascular Dementia: SPECT can detect blood flow abnormalities throughout the brain, which are common in vascular dementia.
Uses gamma emitting radioisotopes. SPECT shows alterations in the dopamine transporter (DAT), reflecting reduced binding in the striatum, which indicates dysfunction or loss of nerve terminals in the substantia nigra. Neurons expressing DAT are concentrated in the caudate and putamen.
What is a FLAIR MRI
Fluid-Attenuated Inversion Recovery MRI
Brain Lesions: FLAIR MRI can show shrinkage or atrophy in specific regions like the hippocampus in Alzheimer’s disease, or widespread cortical atrophy in FTD.
An MRI technique that suppresses the signal of fluids like CSF to enhance the visibility of lesions, particularly in the brain. FLAIR MRI is effective in highlighting lesions against the suppressed background of CSF, making it excellent for detecting brain pathologies such as multiple sclerosis plaques.
What is a SWI scan
Susceptibility Weighted Imaging (Quantitative Susceptibility Imaging)
Neurodegenerative Diseases: SWI is valuable in studying diseases such as Alzheimer’s where iron deposition in the brain is a marker of disease progression. It can quantify these iron deposits more accurately than other methods. Also, SWI can detect and differentiate between blood degradation products (like hemosiderin) following microbleeds or haemorrhagic strokes, crucial for stroke assessment and treatment planning
This MRI technique focuses on the magnetic susceptibility differences of tissues, providing detailed images that reveal variations in tissue composition, particularly iron and other paramagnetic substances.
Identifying Dementia types on Brain Specimens
Alzheimer’s: Amyloid plaques, neurofibrillary tangles.
Vascular: Infarcts, blood vessel changes.
Lewy Body: Lewy bodies in the cortex.
FTD: Frontal/temporal atrophy, sometimes with Pick bodies.
Pharmacological Management of Dementia
Acetylcholinesterase inhibitors (e.g., Donepezil) for Alzheimer’s. (mild-to-moderate)
Memantine for moderate to severe dementia.
SSRIs for mood symptoms, sleep aids for disrupted sleep.
what are the characteristics of Lewy body dementia
marked by the presence of Lewy bodies (abnormal deposits of the protein alpha-synuclein) in brain cell
symptoms of Lewy body dementia
sleep disturbances, visual hallucinations, fluctuations in cognitive ability
describe what executive function is
Executive function refers to a set of cognitive processes that are essential for controlling behavior and thought processes, allowing individuals to plan, focus attention, remember instructions, and manage multiple tasks successfully. These functions are crucial for goal-directed behavior and are primarily managed by the frontal lobes of the brain, particularly the prefrontal cortex.
