Dementia & Cognitive Decline Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What cognitive function is most frequently affected in dementia?

Memory (correct)

Language comprehension

Visual perception

Decision making

Which of the following factors is NOT typically considered a risk during early life for dementia?

Cognitive reserve (correct)

Poor nutrition

Traumatic brain injury

Lower levels of education

How does hearing impairment in midlife relate to dementia pathology?

It is linked to reduced connectivity in the brain's reward pathways.

It leads to increased neurogenesis in the hippocampus.

It correlates with a decline in white matter integrity.

It is associated with pronounced decline in temporal lobe volume. (correct)

Which type of dementia is associated with hyperphosphorylated tau pathology?

Traumatic Brain Injury related dementia Signup and view all the answers

What is the effect of hypertension in midlife on brain health?

It is linked to diminished brain volumes and increased white matter hyperintensity. Signup and view all the answers

Which factor has been shown to improve cognitive ability until a certain age?

Education Signup and view all the answers

Which type of dementia is characterized by distinctive cellular inclusions and varying levels of glial activation?

All types of dementia Signup and view all the answers

What is a key difference between arteriolosclerosis and cerebral amyloid angiopathy?

Arteriolosclerosis results in the loss of normal vessel wall structure. Signup and view all the answers

How do cerebrovascular and neurodegenerative lesions affect cognitive decline when they coexist?

They produce a decline exceeding individual disease impacts. Signup and view all the answers

What common factor connects cognitive decline, Mild Cognitive Impairment, Alzheimer’s Disease, and hearing loss?

Brain atrophy. Signup and view all the answers

What was a significant finding in the study of the US population regarding hearing impairment and cognition?

Cognitive decline persisted below the clinical threshold of hearing impairment. Signup and view all the answers

What might be influenced by physiological vascular motion in the context of dementia development?

The compromise of the blood-brain barrier. Signup and view all the answers

What percentage of frontotemporal dementia cases reportedly have a family history of dementia?

40% Signup and view all the answers

What is the most common age group affected by Pick's disease regarding early-onset dementia?

Under 65 years Signup and view all the answers

Which of the following subtypes does not categorize Pick's disease?

Cognitive variant Signup and view all the answers

What is a notable anatomical feature of the cortical atrophy in Pick's disease?

Knife-edge atrophy Signup and view all the answers

What characterizes the neurons that remain after the significant loss in Pick's disease?

Highly argentophilic with inclusions Signup and view all the answers

Which of these statements about Pick bodies is false?

They are angular in shape like NFTs. Signup and view all the answers

In clinical features of Pick's disease, which symptom is least likely to be observed?

Severe memory loss Signup and view all the answers

What physiological condition marks the loss of neurons in Pick's disease?

Astrogliosis Signup and view all the answers

How does the pathology of Pick's disease differentiate it from Alzheimer's disease?

Spherical intraneuronal aggregates known as Pick bodies Signup and view all the answers

Which of these diseases ranks third as a cause of dementia in individuals over 65?

Pick's disease Signup and view all the answers

What is a characteristic symptom of individuals with the behavioral variant of the disorder?

Euphoria Signup and view all the answers

Which variant of Primary Progressive Aphasia involves difficulty in generating words?

Nonfluent/agrammatic variant Signup and view all the answers

Lewy body dementia is classified into which two primary presentations?

Parkinson’s disease and dementia with Lewy bodies Signup and view all the answers

What is the main pathological feature of Lewy body disease as contrasted with Alzheimer's disease?

Presence of Lewy body inclusions Signup and view all the answers

Which statement is true regarding the onset of symptomatic sporadic Pick disease?

It starts during mid-adult life. Signup and view all the answers

Which biological factor is implicated in the pathophysiology of Lewy body dementia?

Alpha-synuclein aggregates Signup and view all the answers

What cognitive ability tends to be compromised in individuals with the behavioral variant of the disorder?

Abstract thinking Signup and view all the answers

What is a distinguishing feature of Frontotemporal dementia as compared to more common dementias like Alzheimer’s?

The absence of memory loss in initial stages Signup and view all the answers

Which of the following conditions may accompany any of the three clinical syndromes of Frontotemporal dementia?

Motor neuron disease Signup and view all the answers

Which of the following affects the prognosis of symptomatic sporadic Pick disease?

Age of onset Signup and view all the answers

Which part of the brain is primarily affected in memory impairment due to dementia?

Medial temporal lobes Signup and view all the answers

What type of lesions is most associated with language function impairment in dementia?

Dominant cerebral hemisphere lesions Signup and view all the answers

Which area is typically associated with loss of reading and calculation abilities in dementia?

Posterior part of the left cerebral hemisphere Signup and view all the answers

Which type of cognitive dysfunction is linked to lesions in the dominant parietal region?

Loss of use of tools and imitation of gestures Signup and view all the answers

Which type of degeneration is especially implicated in the progression of Alzheimer's disease?

Cholinergic nuclei degeneration Signup and view all the answers

Which neuroanatomical region's degeneration can lead to modulation problems in behavior and stability of personality?

Frontal lobe Signup and view all the answers

What is a common feature of neurodegenerative disorders related to protein biochemistry?

Intracellular inclusions Signup and view all the answers

How does the disruption of normal protein homeostasis affect neurodegenerative disorders?

It plays a central role in disorder progression. Signup and view all the answers

What is a significant consequence of thalamic degeneration regarding memory?

Disrupted communication with the cortex Signup and view all the answers

Study Notes

Dementia Overview

Dementia is a decline in cognitive ability over time, impacting daily activities, primarily affecting memory.
Significant cognitive impairment hinders routine tasks.
Dementia involves cellular inclusions and extracellular protein accumulation, with varying glial and microglial activation.

Learning Outcomes

Review the pathophysiology and risk factors of dementia types
- Alzheimer's Disease
- Vascular Dementia
- Lewy Body dementia
- Frontotemporal Dementia
- Parkinson's Dementia
Critique the modifiable risk for dementia: hearing impairment.
Hypothesize the pathophysiology of traumatic brain injury and its relation to dementia etiology.
Critique the connection between gut microbiome and the pathophysiology of dementia.

Risk Factors

Early Life (Under 45 years): Lower education levels impact cognitive reserve.
Midlife (45-65 years) & Later Life (Over 65 years): Risk factors further impact cognitive reserve and initiate neuropathological processes.
Less Education: Cognitive ability typically improves with education, but plateaus in late adolescence, beyond 20 years, gains in cognitive ability is limited with additional education.
Cognitive Decline: Individuals in cognitively challenging occupations experience less cognitive decline, both before and after retirement.
Hearing Loss: Hearing impairment in midlife is linked to a more pronounced decline in temporal lobe volume (hippocampus and entorhinal cortex).
Traumatic Brain Injury (TBI): Solitary and severe TBI is correlated with extensive hyperphosphorylated tau pathology.
Hypertension: Hypertension (starting age 40) is associated with diminished brain volumes and heightened white matter hyperintensity, with no observed association with amyloid deposition.
Alcohol Consumption: Consuming over 21 units per week and prolonged abstinence are linked to a 17% rise in dementia risk compared to consuming less than 14 units. Overconsumption of alcohol is linked to right-sided hippocampal atrophy in MRI scans.
Obesity: Higher BMI is linked to the development of dementia.
Smoking: Ceasing smoking reduces the risk, with exposure to secondhand smoke associated with greater memory decline. Duration of exposure intensifies the risk.
Depression: A component of prodrome and initial phases of dementia. Can lead to reverse causation where depressive symptoms may precede dementia.
Social Isolation: Reduces the cognitive reserve, which is a protective factor for promoting positive behaviors. Reduced social contact raises dementia risk.
Physical Inactivity: Individuals may discontinue exercise due to dementia's early signs, and this is a risk factor for individuals with cardiovascular morbidity.
Air Pollution: Airborne particulate pollutants expedite neurodegenerative processes, influencing cerebrovascular and cardiovascular diseases, Aβ deposition, and amyloid precursor protein processing.
Diabetes: Type 2 diabetes poses a distinct risk for dementia onset.

Dementia - Pathophysiology

Degenerative Types: Pathological anatomy is widespread, making it challenging to pinpoint specific areas. Memory impairment is a central feature, occurring with extensive disease in parts of the cerebrum, while the diencephalon's and medial temporal lobe's integrity is fundamental for memory. Language function impairment is closely associated with disease in the dominant hemisphere (frontal, temporal, and parietal lobes). Also, reading and calculation capacity loss relates to posterior lesions of the dominant cerebral hemisphere. Damage to tools, gestures (apraxias), and drawing or constructing simple and complex figures (more frequently right-sided lesions) is related to parietal lobe degeneration. Behavior and personality stability issues are often from frontal lobe degeneration.
Cerebral Disease: Clinical manifestation varies based on lesion location and extent. Diencephalon and basal ganglia implication are also implicated.
Biochemistry of Proteins: Intracellular and intracytoplasmic inclusions are deeply intertwined with neurodegenerative disorders. Protein homeostasis disruption plays a central role. In neurodegenerative disorders, inclusions compromise native cellular proteins and their stress response conjugates. Cells activate stress responses in presence of damage.
Accumulations of Proteins: These aggregations obstruct axons, dendrites, hampering cellular protein recycling, and disrupting homeostasis. They create toxic fibrils that perpetuate and intensify cellular stress. Fundamental neurodegenerative diseases revolve around proteostasis.
Arteriosclerotic Cerebrovascular Disease: Follow a distinct trajectory from neurodegenerative diseases. Involves multiple infarctions, affecting motor, sensory, visual, and association areas. Recurring strokes impair intellectual function, resulting in multi-infarct or vascular dementia.
Severe Cerebral Trauma: Located in cerebral convolutions (frontal and temporal poles, corpus callosum, and thalamus). Also, there are cases where deep white matter mechanical disruption occurs leading to axonal shearing or diffuse axonal injury. Some dementia cases don't involve brain tissue destruction, but chronic hydrocephalus is frequently linked to cognitive decline due to compression of cerebral white matter.
Diffuse Inflammatory Process: Inflammatory processes (syphilis, cryptococcosis, chronic meningitides, and viral infections like HIV encephalitis) disrupt neuron function, both due to a reduction in neurons and inflammatory response in remaining neurons.
Prion Diseases: Are associated with widespread loss of cortical neurons, with spongiform changes leading to distinct cognitive dysfunction patterns. Adult forms of leukodystrophy typically exhibit subcortical dementia with prominent frontal lobe features. Extensive white matter lesions result from advanced multiple sclerosis, progressive multifocal leukoencephalitis, or certain vascular dementias.

Dementia Types

Alzheimer's Disease (AD): Most common neurodegenerative dementia type. Characterized by abnormal accumulation of ẞ-amyloid and tau proteins. Results in gradual, progressive memory loss, cognitive impairment, and dementia. More prevalent in older people (over 65), but incidence is low under the age of 65 and is highest over 85. Women are affected twice as often as men.
Pathology of AD: Cortical atrophy is evident with widened sulci and narrowed gyri. Parahippocampal regions are particularly affected. Atrophy intensifies across temporal, frontal, and parietal cortex. Neuritic plaques(senile plaques) are ẞ-amyloid extracellular deposits. They occupy substantial volumes of affected cerebral grey matter. These plaques exhibit reactive astrocytes and microglia, with swollen and distorted neuronal processes (dystrophic neurites). Neurofibrillary tangles are collections of polymerized tau filaments found intracytoplasmically. These filament distributions are associated with the clinical severity of Alzheimer's disease. Tangles in the entorhinal cortex and parahippocampal gyrus can be observed in asymptomatic individuals years before typical AD onset; this suggests early disease stages. Cytopathologic features involve hyperphosphorylated tau protein binding to microtubules. Extracellular amyloid plaques have a ẞ-amyloid core and reactive glial cells. ẞ-amyloid peptides are derived from APP(amyloid precursor protein) through a series of hydrolytic steps by different enzymes. Toxic peptides from the breakdown of this protein aggregate, adhere to receptors causing influx, and causes a triggering of an inflammatory response, resulting in intracellular tangles and eventual cell death.
Pick Disease (Frontotemporal Lobe Dementia - FTLD): Characterized by abnormal tau accumulation without ẞ-amyloid. It typically starts in the fifth to seventh decades, being nearly as prevalent as AD in this age group. It is initially characterized by disruptive and inappropriate behaviors, in contrast to AD, which starts with memory difficulties. Often hereditary, with up to 40% of cases having a family history of dementia.
Pathology of Pick Disease: Cortical atrophy is the main feature, primarily in the frontotemporal regions; atrophy can reach sever levels. Affected gyri are reduced to thin slivers—a knife-edge atrophy. Cytopathologic features involve the presence of neuronal cytoplasmic inclusions, known as Pick bodies, which results from the dense aggregation of straight tau filaments.
Lewy Body Disease (LBD): Presents as either Parkinson's disease and dementia or dementia with Lewy bodies (DLB). The second most common cause of neurodegenerative dementia. Characterized by the widespread involvement of cortical neurons with Lewy body inclusions, but typically having a lack of, or minimal, neurofibrillary tangles or amyloid plaques.
Pathology of LBD: Lewy bodies are intraneuronal cytoplasmic inclusions, consisting of straight neurofilaments. The inclusions show the presence of epitopes recognized by antibodies against phosphorylated and non-phosphorylated neurofilament proteins, ubiquitin, and a-synuclein. Lewy bodies and Lewy neurites are found in the substantia nigra, amygdala, cingulate gyrus and the neocortex.
Vascular Dementia: Subset of dementia cases primarily results from one or more symptomatic strokes. Involves multiple infarctions throughout thalami, basal ganglia, brainstem, and cerebrum, affecting multiple areas. Results in strokes, vascular lesions, contribute to impaired intellectual function, resulting in multi-infarct or vascular dementia. This is more commonly prevalent with limited access to medical care.

Hearing Impairment and Dementia

Sensorineural hearing loss (SNHL) in the elderly is related to age, with varying mechanisms affecting the auditory pathways.
Brain atrophy is a common factor connecting cognitive decline, Mild Cognitive Impairment, Alzheimer's Disease, and hearing loss.
A cross-sectional study indicated a decline in cognition with each 10 dB reduction in hearing level, persisting even below clinical thresholds (below 25 dB).
The theories propose that hearing loss elevates the cognitive load leading to an increase in brain effort to process speech, causing structural changes in the brain and impacting neurodegeneration in working memory. This is connected to a decrease in overall brain volume and primary auditory cortex in the temporal lobe. Impaired activation of auditory-limbic pathway, and atrophy to frontal lobes and hippocampi result from hearing loss.
Both hearing loss and cognitive impairment likely stem from a shared neurodegenerative aging process in the brain, affecting stria vascularis, hair cells, and primary afferent neurons, and impacting neurotransmitter release.
Social disengagement arises from issues in communication, from hearing loss, resulting in social isolation, reduced cognitive stimulation, apathy, depression, and potentially increased pro-inflammatory gene expression and impacting brain functions.

Traumatic Brain Injury (TBI) and Dementia

Severe TBI, particularly recurrent mild TBIs, can trigger prolonged neurodegenerative processes, resulting in pathological features similar to Alzheimer's.
Determining specific types of post-traumatic dementia remains challenging, though cerebrovascular dysfunction (CVD) plays a crucial role in the onset of dementia.

Gut Microbiome and Dementia

Accumulating evidence indicates a significant role of intestinal microbiota in initiating and progressing neurodegenerative diseases, with reports highlighting a connection between intestinal microbiota dysfunctions and dementia.
Mounting data suggests gut microbiota's involvement in various conditions, including obesity, diabetes, cancers, aging, autoimmune diseases, and neuropsychiatric disorders like depression and AD.
Gut microbiota's impact on AD pathogenesis is recognized through several pathways, which involves abnormalities in Aβ, tau phosphorylation, inflammation, neurotransmitter dysregulation, and oxidative stress.

Post-Assessment MCQs

MCQ 1: Alzheimer’s disease (AD) is characterized by the accumulation of amyloid plaques and neurofibrillary tangles.
MCQ 2: Parkinson's dementia is associated with motor symptoms like tremors, rigidity, and bradykinesia.
MCQ 3: Vascular dementia results from impaired blood flow to the brain (multiple small strokes), resulting in gradual cognitive decline.

References

Include the provided references in your study notes.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the cognitive functions affected by dementia and the factors influencing cognitive health. This quiz covers various types of dementia, risk factors, and the relationship between hearing impairment and cognitive decline. Perfect for students and enthusiasts of neuroscience and psychology.