Dementia refers to a clinical syndrome characterized by progressive cognitive decline that interferes with the ability to function independently.
Individuals suffering from dementia experience changes in cognition, function, and behaviors.
The clinical presentation of dementia varies greatly among individuals,
Cognitive impairment stems from injury to the cerebral cortex caused by synaptic failure, inflammation, and change in cerebral metabolism.
Symptoms
Some of the most common symptoms of dementia are:
agitation
apathy
aggression
psychosis
hallucinations
Delusions
Cognitive deficits may present as:
memory loss
communication and language impairments
agnosia (inability to recognize objects)
apraxia (inability to perform previously learned tasks)
impaired executive function (reasoning, judgement and planning)
Symptoms Vs. Pharmacotherapy
Symptoms that don’t respond well to pharmacotherapy,
behavioral and psychological symptoms such as:
wandering
hoarding
inappropriate behaviors (e.g., sexual disinhibition, eating inappropriate objects)
repetitive behaviors
restlessness
6 Cognitive Domains Affected by Dementia
Learning & memory
Language
Complex attention
Executive function
Perceptual-motor
Social cognition
Can be classified as mild or major, depending on the severity of symptoms
Mild Cognitive Impairment (MCI)
Patients with mild deficits who do not meet the criteria for dementia are considered to have mild cognitive impairment (MCI)
Experience difficulties with:
Memory
Language
Thinking
Judgement
Impairments are insufficient to interfere with daily life and independence
In early stages of Alzheimer’s disease individuals may present with MCI.
MCI patients are at higher risk of developing Alzheimer’s disease and other dementias than those without MCI
Subtypes of Dementia
Dementia is an umbrella term used to describe a clinical syndrome of progressive cognitive decline, but its subtypes are classified according to the cause of dementia.
The 4 common types of dementia—
Alzheimer's Disease
vascular dementia
Lewy body dementia
frontotemporal dementia
Alzheimer’s Disease
Most common, 60% to 80% of cases
Onset is usually undetectable, but short-term memory loss is usually the first sign
Caused by accumulation of beta-amyloid plaques and neurofibrillary tangles, first in entorhinal cortex and the hippocampus
Decrease in cholinergic neurotransmission causes loss of memory and cognition.
As it spreads to other parts of the brain, neurons progressively die in affected regions
Genetics is a contributing factor
Late-onset: after the age of 60
Early-onset: ages 30 to 60
Alzheimer’s Symptoms
Cognitive symptoms include:
Memory loss (poor recall, losing items)
Aphasia
Agnosia
Apraxia
Disorientation (impaired perception of time, unable to recognize familiar people)
Impaired visuospatial function and executive function
Noncognitive symptoms:
Depression
Psychotic symptoms (hallucinations, delusions)
Behavioral symptoms (such as physical and verbal aggression, motor hyperactivity, uncooperativeness, wandering, repetitive mannerisms and activities and combativeness).
Vascular Dementia
Second most prevalent form of dementia (20%)
Also called Multiinfarct Dementia
Sudden or gradual onset
Mixed dementia = co-existence of AD & vascular dementia
Correlated with:
o Cerebrovascular Disease:
o Stroke,
o Lacunar infarcts
o Atherosclerotic Comorbidities:
o Diabetes
o Hypertension
o Coronary heart disease
Results from neuronal deprivation of oxygen
Stroke is the most common cause
Symptoms vary by affected regions of the brain and the severity of the blood vessel damage.
Major stroke = confusion, disorientation, difficulty with speaking, understanding speech and vision loss
Memory may not be affected (mild memory impairment in early stage), but a sudden change in executive function (e.g., thinking, reasoning) after stroke can occur.
Lewy Body Dementia
Caused by abnormal deposits of alpha-synuclein protein (Lewy bodies) inside neurons
5% to 15% of all dementias
Fluctuating cognitive impairment
Recurrent complex visual hallucinations
Memory loss tends to be observed in advanced LBD.
More than 80% of individuals with LBD develop parkinsonism
Other Symptoms:
Lethargy
Daytime somnolence
Sustained periods of staring into space
Periods of improved memory
Episodes of disorganized speech
Periods of decreased attention
Frontotemporal Dementia
Describes disorders that affect the frontal & temporal lobes , such as Pick’s disease
Occur at a younger age (40-75 years) than does AD.
Personality changes and behavioral disturbances are key features and occur early in the disease.
Visuospatial function is usually not affected
Behavioral disturbances: apathy, aggression, agitation
Less memory impairment in early stage
In Conclusion
Managing dementia is particularly challenging because of the complexity of the disorder
Treatment plan for each patient should be individualized to provide the most effective and safe therapy.