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Understanding Different Types of Dementia

Summary

This chapter introduces the major types of dementia and their distinguishing characteristics. You will learn about Alzheimer's disease (the most common form), vascular dementia, Lewy body dementia, frontotemporal dementia, and mixed dementia. The chapter also covers less common forms including cerebrovascular disease, mini-strokes, and rare dementia types such as Wernicke-Korsakoff syndrome, Creutzfeldt-Jakob disease, Huntington's disease, Parkinson's disease dementia, and normal pressure hydrocephalus. Understanding these different types will help you recognize that dementia is not a single disease but rather a collection of conditions with varying causes and presentations.

Concepts Covered

This chapter covers the following 12 concepts from the learning graph:

  1. Alzheimer's Disease
  2. Vascular Dementia
  3. Lewy body Dementia
  4. Frontotemporal Dementia
  5. Mixed Dementia
  6. Cerebrovascular Disease
  7. Mini-Strokes
  8. Wernicke-Korsakoff Syndrome
  9. Creutzfeldt-Jakob Disease
  10. Huntington's Disease
  11. Parkinson's Disease Dementia
  12. Normal Pressure Hydrocephalus

Prerequisites

This chapter builds on concepts from:

Why Are There Different Types of Dementia?

In Chapter 1, we learned that dementia is a syndrome—a collection of symptoms—rather than a single disease. Just as "fever" can be caused by many different illnesses, "dementia" can result from many different brain conditions. Each type of dementia has distinct causes, affects different brain regions, progresses at different rates, and produces characteristic patterns of symptoms.

Understanding the different types of dementia is important for several reasons:

  • Diagnosis - Different types require different diagnostic approaches
  • Treatment - Some treatments work better for specific types
  • Prognosis - Different types progress at different rates
  • Care planning - Each type presents unique challenges for caregivers
  • Research - Understanding causes helps develop targeted treatments

While the symptoms of different dementia types overlap considerably, each has distinguishing features that help doctors make an accurate diagnosis. In this chapter, we'll explore each major type, learning what causes it, which brain regions it affects, and what makes it unique.

How Common Are Different Types of Dementia?

Before diving into specifics, it's helpful to understand how common each type is. Alzheimer's disease is by far the most common cause of dementia, accounting for 60-80% of all cases. However, many people have more than one type simultaneously, which we call mixed dementia.

Here's the approximate breakdown of dementia cases:

  • Alzheimer's disease - 60-80% of cases
  • Vascular dementia - 10-20% of cases (second most common)
  • Lewy body dementia - 5-10% of cases
  • Frontotemporal dementia - 5-10% of cases (more common in people under 65)
  • Mixed dementia - 10-20% of cases (often Alzheimer's plus vascular)
  • Other rare types - Less than 5% combined

These percentages overlap because many people have mixed dementia—two or more types occurring together. As diagnostic techniques improve, we're discovering that mixed dementia is more common than previously thought.

Diagram: Dementia Types Prevalence Chart

Dementia Types Prevalence Interactive Chart

Type: chart

Learning Objective: Understand the relative prevalence of different dementia types (Bloom Level 2 - Understand)

Bloom Taxonomy Level: Understand (L2) Bloom Verb: Compare, interpret

Purpose: Visualize the relative frequency of different dementia types to understand which are most common

Chart type: Interactive pie chart with detailed breakdown

Data to display: - Alzheimer's disease: 60-70% (largest slice, blue) - Vascular dementia: 15-20% (orange) - Mixed dementia: 10-15% (purple) - Lewy body dementia: 5-10% (green) - Frontotemporal dementia: 5-10% (yellow) - Other rare types: 1-5% (gray)

Visual Features: - Pie chart with clear percentage labels - Color-coded slices - Total cases represented: "Approximately 55 million people worldwide"

Interactive Elements: - Hover over slice: Shows detailed information - Exact percentage range - Estimated number of people affected - Key characteristics - Typical age of onset - Click on slice: Expands to show sub-categories - Example: "Other rare types" expands to show individual rare dementias - Toggle view: Switch between pie chart and bar chart - "Show Age Distribution" button: Overlay showing which types are more common at different ages

Additional Information Panels: For each dementia type (on hover/click): - Most affected age group - Male vs. female prevalence - Geographic variations if significant - Trend over time (increasing/stable/decreasing diagnosis rates)

Annotations: - "60-70%: Alzheimer's disease is by far the most common type" - "Mixed dementia often goes undiagnosed until autopsy" - "FTD is the most common dementia in people under 60"

Responsive Design: - Chart resizes to fit screen width - Labels remain readable at all sizes - Touch-friendly for mobile devices

Implementation: Chart.js or D3.js with custom interactions Canvas size: 100% width, 500px height

Alzheimer's Disease: The Most Common Type

Alzheimer's disease is not just the most common type of dementia—it's also the most well-known and heavily researched. Named after Dr. Alois Alzheimer, who first described it in 1906, this disease involves specific changes in brain tissue that disrupt normal brain function.

What Causes Alzheimer's Disease?

Alzheimer's disease is caused by abnormal buildups of proteins in and around brain cells. Two types of protein deposits characterize Alzheimer's:

  • Amyloid plaques - Sticky clumps of beta-amyloid protein that build up between neurons
  • Neurofibrillary tangles - Twisted fibers of tau protein that form inside dying cells

These protein deposits damage and kill neurons, particularly in the hippocampus (memory center) and cerebral cortex (thinking and planning center). As neurons die, the brain shrinks, and cognitive abilities decline. The disease typically begins decades before symptoms appear, with proteins slowly accumulating while the brain can still compensate.

Brain Regions Affected

Alzheimer's disease typically affects the brain in a predictable pattern:

  1. Hippocampus (first and most severely affected)
  2. Results in difficulty forming new memories

  3. Explains why recent memories are lost before old ones

  4. Temporal lobes

  5. Causes problems with language and word-finding

  6. Affects ability to recognize familiar faces

  7. Parietal lobes

  8. Leads to spatial disorientation

  9. Makes tasks like dressing or navigation difficult

  10. Frontal lobes (affected in later stages)

  11. Impacts judgment and decision-making
  12. Changes personality and behavior

Characteristic Symptoms

The hallmark symptom of Alzheimer's disease is progressive memory loss, especially for recent events. Other common symptoms include:

  • Difficulty remembering recent conversations or events
  • Problems with language (finding words, following conversations)
  • Disorientation to time and place
  • Poor judgment and decision-making
  • Withdrawal from social activities
  • Changes in mood and personality
  • Difficulty with familiar tasks
  • Misplacing items in unusual places

Early-Onset vs. Late-Onset Alzheimer's

Most people develop Alzheimer's after age 65 (late-onset). However, about 5-10% of cases occur before age 65 (early-onset). Early-onset Alzheimer's often progresses more quickly and is more likely to have a genetic component.

Vascular Dementia: When Blood Flow Is Disrupted

Vascular dementia is the second most common type of dementia, caused by reduced blood flow to the brain. Unlike Alzheimer's, which involves protein deposits, vascular dementia results from damage to blood vessels that supply the brain with oxygen and nutrients.

What Causes Vascular Dementia?

Vascular dementia occurs when brain cells are damaged due to inadequate blood supply. This can happen in two main ways:

Cerebrovascular disease refers to conditions affecting blood vessels in the brain, including:

  • Stroke - A single large stroke can cause sudden, significant cognitive decline
  • Mini-strokes (TIAs) - Multiple small strokes that each cause minor damage, but accumulate over time
  • Small vessel disease - Damage to tiny blood vessels deep in the brain

Risk factors for vascular dementia are the same as those for heart disease and stroke:

  • High blood pressure (hypertension)
  • High cholesterol
  • Diabetes
  • Smoking
  • Obesity
  • Atrial fibrillation
  • History of heart disease

Mini-Strokes and Step-Wise Decline

One distinctive feature of vascular dementia is its often "stepwise" progression. Unlike Alzheimer's, which gradually worsens over time, vascular dementia may suddenly worsen following a stroke or mini-stroke (transient ischemic attack), then stabilize for a period before the next event causes another decline.

Mini-strokes are temporary blockages of blood flow that don't cause permanent symptoms on their own but can accumulate to cause dementia. Many people don't even realize they've had mini-strokes until brain imaging reveals multiple small areas of damage.

Brain Regions Affected

The symptoms of vascular dementia depend on which parts of the brain are affected by reduced blood flow. Common patterns include:

  • Subcortical vascular dementia - Affects deep brain structures, causing slowed thinking and movement problems
  • Cortical vascular dementia - Affects outer brain layers, causing problems similar to Alzheimer's
  • Mixed patterns - Damage in multiple areas

Characteristic Symptoms

Vascular dementia symptoms vary more than Alzheimer's symptoms because they depend on where blood vessel damage occurs. Common features include:

  • Slowed thinking and processing speed
  • Difficulty with planning and organization
  • Problems with attention and concentration
  • Mood changes, especially depression
  • Physical symptoms (weakness, paralysis, vision changes) if caused by stroke
  • Memory problems (but often less severe than in Alzheimer's)
  • Changes in walking (shuffling, small steps)

Unlike Alzheimer's, memory may be relatively preserved in early vascular dementia, while executive functions (planning, organizing, decision-making) are more impaired.

Prevention Matters

Vascular dementia is the most preventable type of dementia. Controlling blood pressure, cholesterol, and diabetes, along with not smoking and exercising regularly, can significantly reduce risk.

Lewy Body Dementia: More Than Memory Problems

Lewy body dementia (LBD) is the third most common type of dementia, though it's often misdiagnosed because its symptoms overlap with both Alzheimer's disease and Parkinson's disease. It's caused by abnormal deposits of a protein called alpha-synuclein, which form structures called Lewy bodies in the brain.

What Causes Lewy Body Dementia?

Lewy bodies are abnormal clumps of the protein alpha-synuclein that build up inside neurons. These deposits interfere with chemical messengers in the brain, particularly dopamine (important for movement) and acetylcholine (important for thinking and memory).

Scientists don't fully understand why Lewy bodies form, but they appear in specific brain regions:

  • Cortex - Causing cognitive problems
  • Brainstem - Causing movement problems
  • Substantia nigra - Affecting dopamine production (same area affected in Parkinson's disease)

Relationship to Parkinson's Disease Dementia

Lewy body dementia and Parkinson's disease dementia are closely related conditions, both involving Lewy body deposits. The main difference is timing:

  • Lewy body dementia - Cognitive symptoms appear first or within a year of movement problems
  • Parkinson's disease dementia - Movement problems (tremor, rigidity, slow movement) appear years before cognitive decline

Both are sometimes grouped together as "Lewy body dementias" because the underlying brain changes are similar.

Characteristic Symptoms

Lewy body dementia has three hallmark features that distinguish it from other types:

  1. Fluctuating cognition
  2. Alertness and attention vary dramatically day-to-day or even hour-to-hour
  3. A person may be lucid and coherent one moment, confused the next

  4. This fluctuation is unique to LBD

  5. Visual hallucinations

  6. Seeing things that aren't there, typically detailed and realistic
  7. Often seeing people or animals

  8. Unlike delusions, the person may recognize these aren't real

  9. Movement problems (Parkinsonism)

  10. Shuffling walk
  11. Muscle stiffness
  12. Tremor (though less common than in Parkinson's disease)
  13. Frequent falls

Additional symptoms common in Lewy body dementia include:

  • REM sleep behavior disorder (acting out dreams)
  • Severe sensitivity to antipsychotic medications
  • Problems with automatic functions (blood pressure, temperature, digestion)
  • Depression and anxiety
  • Spatial disorientation
  • Problems with executive functions

Medication Sensitivity

People with Lewy body dementia can have severe, sometimes life-threatening reactions to typical antipsychotic medications. It's crucial that doctors know about an LBD diagnosis before prescribing medications.

Frontotemporal Dementia: Changes in Personality and Behavior

Frontotemporal dementia (FTD) is less common than Alzheimer's or vascular dementia, but it's the most common cause of dementia in people under age 60. Unlike other dementias that primarily affect memory, FTD primarily causes changes in personality, behavior, and language.

What Causes Frontotemporal Dementia?

Frontotemporal dementia is caused by progressive damage to the frontal and temporal lobes of the brain—the areas responsible for personality, behavior, and language. Different abnormal proteins can accumulate in these regions, including tau protein (like in Alzheimer's, but in different forms) and TDP-43 protein.

About 30-40% of FTD cases are inherited, caused by mutations in specific genes. This is a much higher hereditary rate than in Alzheimer's disease.

Brain Regions Affected

As the name suggests, frontotemporal dementia primarily affects:

  • Frontal lobes - Control behavior, personality, judgment, planning, and speech production
  • Temporal lobes - Process language comprehension and semantic memory (knowing what things mean)

The specific symptoms depend on which areas are most affected, leading to different FTD subtypes.

Types of Frontotemporal Dementia

There are three main variants of FTD, each with distinct symptoms:

Behavioral variant FTD (bvFTD): - Most common form - Dramatic personality and behavior changes - Loss of empathy and social awareness - Impulsive, inappropriate behavior - Apathy or lack of motivation - Compulsive behaviors - Changes in eating habits - Memory relatively preserved in early stages

Semantic variant FTD (svFTD): - Progressive loss of word meaning - Difficulty naming objects - Surface reading (can read aloud but doesn't understand) - Behavior changes may develop later

Nonfluent/agrammatic variant FTD (nfvFTD): - Difficulty producing speech - Hesitant, effortful speaking - Grammar errors - Speech becomes sparse and telegraphic - Comprehension relatively preserved

Characteristic Symptoms

The key distinguishing feature of frontotemporal dementia is that personality and behavior changes often occur before significant memory problems. Common symptoms include:

  • Loss of social inhibitions (saying/doing inappropriate things)
  • Lack of empathy or interest in others
  • Compulsive or ritualistic behaviors
  • Overeating or craving sweets
  • Loss of insight (not recognizing changes)
  • Language difficulties (depending on type)
  • Executive dysfunction (planning, organizing)
  • Emotional flatness or excessive emotions

Unlike Alzheimer's, a person with FTD may score well on memory tests but show dramatic changes in personality that make daily life and relationships extremely difficult.

Mixed Dementia: When Types Overlap

Mixed dementia refers to having two or more types of dementia simultaneously. The most common combination is Alzheimer's disease with vascular dementia, but other combinations occur. Mixed dementia becomes more common with increasing age.

Why Mixed Dementia Is Important

Mixed dementia is more common than once thought. Studies examining brain tissue after death find that many people diagnosed with "pure" Alzheimer's disease actually had significant vascular damage as well. Understanding mixed dementia is important because:

  • It may progress faster than a single type alone
  • Treatment needs to address multiple pathologies
  • Risk factors (like high blood pressure) may matter more than previously recognized
  • It explains why some people don't respond as expected to Alzheimer's treatments

Common Combinations

The most frequent mixed dementia combinations include:

  • Alzheimer's disease + Vascular dementia - Most common combination
  • Lewy body dementia + Alzheimer's disease - Lewy bodies plus amyloid plaques
  • Vascular dementia + Lewy body dementia - Blood vessel damage plus Lewy bodies

Diagnosis Challenges

Mixed dementia can be challenging to diagnose during a person's lifetime because:

  • Symptoms from different types overlap
  • Brain imaging may show changes typical of multiple types
  • The dominant type may mask signs of other types
  • Definitive diagnosis often requires brain tissue examination after death

Doctors typically diagnose and treat the most prominent dementia type while remaining alert for features suggesting additional pathology.

Diagram: Dementia Types Comparison Matrix

Interactive Dementia Types Comparison Tool

Type: infographic

Learning Objective: Analyze and compare the distinguishing features of major dementia types (Bloom Level 4 - Analyze)

Bloom Taxonomy Level: Analyze (L4) Bloom Verb: Compare, contrast, differentiate, distinguish

Purpose: Help students identify key differences between major dementia types across multiple dimensions

Layout: Interactive comparison matrix with dementia types as columns and characteristics as rows

Dementia Types Displayed (Columns): 1. Alzheimer's Disease 2. Vascular Dementia 3. Lewy Body Dementia 4. Frontotemporal Dementia 5. Mixed Dementia

Comparison Dimensions (Rows):

  1. Primary Cause:
  2. Alzheimer's: Amyloid plaques and tau tangles
  3. Vascular: Reduced blood flow, strokes
  4. Lewy body: Alpha-synuclein deposits (Lewy bodies)
  5. Frontotemporal: Tau or TDP-43 protein in frontal/temporal lobes

  6. Mixed: Combination of pathologies

  7. First Symptoms:

  8. Alzheimer's: Memory loss for recent events
  9. Vascular: Executive dysfunction, slowed thinking
  10. Lewy body: Fluctuating cognition, hallucinations
  11. Frontotemporal: Personality/behavior changes

  12. Mixed: Varies based on combination

  13. Progression Pattern:

  14. Alzheimer's: Gradual, steady decline
  15. Vascular: Stepwise (sudden drops after strokes)
  16. Lewy body: Fluctuating with gradual decline
  17. Frontotemporal: Progressive, often rapid

  18. Mixed: Variable

  19. Memory Affected:

  20. Alzheimer's: Severely affected early
  21. Vascular: Moderately affected
  22. Lewy body: Moderately affected
  23. Frontotemporal: Relatively preserved early

  24. Mixed: Varies

  25. Movement Problems:

  26. Alzheimer's: Late stages only
  27. Vascular: Possible if strokes affect motor areas
  28. Lewy body: Common, Parkinson-like symptoms
  29. Frontotemporal: Rare (unless motor variant)

  30. Mixed: Depends on combination

  31. Hallucinations:

  32. Alzheimer's: Rare, late stages
  33. Vascular: Uncommon
  34. Lewy body: Common, detailed visual hallucinations
  35. Frontotemporal: Rare

  36. Mixed: Possible if includes LBD

  37. Typical Age of Onset:

  38. Alzheimer's: Usually 65+
  39. Vascular: Usually 65+, often older
  40. Lewy body: Usually 50+
  41. Frontotemporal: Usually 45-65 (younger onset)

  42. Mixed: Usually 70+

  43. Most Affected Brain Regions:

  44. Alzheimer's: Hippocampus, temporal cortex
  45. Vascular: Varies (wherever blood flow reduced)
  46. Lewy body: Cortex, brainstem, substantia nigra
  47. Frontotemporal: Frontal and temporal lobes

  48. Mixed: Multiple regions

  49. Genetic Risk:

  50. Alzheimer's: Some genetic factors (APOE ε4)
  51. Vascular: Family history of stroke/heart disease
  52. Lewy body: Rare genetic cases
  53. Frontotemporal: 30-40% inherited

  54. Mixed: Varies

  55. Available Treatments:

  56. Alzheimer's: Cholinesterase inhibitors, memantine
  57. Vascular: Control vascular risk factors
  58. Lewy body: Cholinesterase inhibitors, dopamine drugs
  59. Frontotemporal: Symptomatic management only
  60. Mixed: Combination approach

Interactive Features: - Hover over any cell: Shows detailed explanation with examples - Click column header: Highlights that dementia type across all rows - Click row header: Highlights that characteristic across all types - "Compare Two Types" mode: - Select any two dementia types - Side-by-side detailed comparison - Highlights similarities and differences - "Quiz Mode": - Given symptoms, identify likely dementia type - Immediate feedback with explanation - Progressive difficulty - Filter by: "Most distinctive features" to see what makes each type unique - "Show Real Cases" button: Brief case studies exemplifying each type

Visual Design: - Color-coded cells: - Green: Strongly characteristic - Yellow: Moderately characteristic - Red: Rare or absent - Gray: Variable or unknown - Icons for quick visual scanning - Clear typography with good contrast

Additional Information Panel: - "Key Diagnostic Features" summary for each type - "Red flags" that suggest a particular diagnosis - "Overlap areas" showing where types are hardest to distinguish

Responsive Design: - Table scrolls horizontally on narrow screens - Sticky headers remain visible - Touch-friendly for tapping cells

Implementation: HTML/CSS/JavaScript with interactive table library Canvas size: 100% width, 650px height

Less Common Types of Dementia

While Alzheimer's, vascular, Lewy body, and frontotemporal dementias account for the vast majority of cases, several rare types also exist. Understanding these helps ensure accurate diagnosis and appropriate care.

Wernicke-Korsakoff Syndrome

Wernicke-Korsakoff syndrome is a form of dementia caused by severe thiamine (vitamin B1) deficiency, most commonly due to chronic alcohol misuse. It actually involves two stages:

  • Wernicke encephalopathy - Acute stage with confusion, vision problems, and loss of muscle coordination
  • Korsakoff syndrome - Chronic stage with severe memory impairment

Key features include:

  • Severe difficulty forming new memories
  • Confabulation (making up information to fill memory gaps)
  • Often preventable with proper nutrition and thiamine supplementation
  • Partial recovery possible if caught early

Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob disease (CJD) is a rare, rapidly progressive, and always fatal brain disorder caused by misfolded proteins called prions. Unlike other dementias, CJD progresses extremely quickly, usually causing death within months.

Characteristics include:

  • Rapidly worsening cognitive impairment
  • Muscle twitching and involuntary movements
  • Vision problems
  • Difficulty walking
  • Most cases are sporadic (unknown cause)
  • Very rare: affects about 1 in 1 million people per year

Huntington's Disease

Huntington's disease is an inherited genetic disorder that causes progressive breakdown of nerve cells in the brain. It affects movement, thinking, and behavior. Unlike most dementias, it's caused by a specific gene mutation that children of affected parents have a 50% chance of inheriting.

Features include:

  • Involuntary jerking or writhing movements (chorea)
  • Difficulty with planning and organization
  • Personality changes, depression
  • Symptoms usually begin in mid-life (30s-50s)
  • Genetic testing can predict who will develop the disease

Normal Pressure Hydrocephalus

Normal pressure hydrocephalus (NPH) is caused by buildup of cerebrospinal fluid in the brain's ventricles, putting pressure on brain tissue. What makes NPH particularly important is that it's one of the few potentially reversible causes of dementia symptoms.

The classic triad of NPH symptoms:

  • Walking difficulty (shuffling gait, frequent falls)
  • Urinary incontinence or urgency
  • Cognitive impairment (slowed thinking, memory problems)

NPH can sometimes be treated by surgically implanting a shunt to drain excess fluid, potentially reversing symptoms if diagnosed early.

Importance of Accurate Diagnosis

Because NPH symptoms can mimic Alzheimer's or vascular dementia but are potentially treatable, it's important for doctors to consider this diagnosis, especially when the classic triad of symptoms is present.

How Doctors Diagnose Different Types

Accurately determining which type of dementia a person has requires careful evaluation. Doctors use a combination of approaches:

Medical history and physical examination: - Detailed symptom timeline - Medication review - Family history - Physical and neurological examination

Cognitive testing: - Memory tests - Language assessments - Executive function tests - Visual-spatial evaluations

Brain imaging: - MRI or CT scans show brain structure and damage patterns - PET scans can show amyloid deposits or metabolic changes - Different dementia types have characteristic imaging patterns

Laboratory tests: - Blood tests to rule out reversible causes (vitamin deficiencies, thyroid problems) - Genetic testing in some cases (especially for FTD or Huntington's)

Specialized tests: - Cerebrospinal fluid analysis (can measure amyloid and tau levels) - Sleep studies (especially for suspected Lewy body dementia) - Neuropsychological testing (detailed cognitive assessment)

Even with all these tools, diagnosis can be challenging because symptoms overlap and many people have mixed dementia. Doctors often make a "probable" diagnosis based on the most characteristic features, remaining open to revising the diagnosis as more information becomes available.

Why Knowing the Type Matters

Understanding which type of dementia a person has is important for several reasons:

Treatment decisions: - Some medications work better for specific types - Avoiding medications that could be harmful (especially important in LBD) - Targeting vascular risk factors in vascular dementia

Prognosis and planning: - Different types progress at different rates - Helps families understand what to expect - Guides advance care planning decisions

Care strategies: - Each type presents unique caregiving challenges - Behavioral symptoms vary by type - Safety concerns differ (falls in LBD, wandering in Alzheimer's)

Research participation: - Clinical trials target specific dementia types - Accurate diagnosis enables appropriate trial enrollment

Genetic counseling: - Particularly important for FTD and Huntington's disease - Helps family members understand their risk

Key Takeaways

Let's review the essential concepts about different types of dementia:

  • Dementia is not a single disease but a syndrome caused by various underlying conditions
  • Alzheimer's disease is the most common type (60-80%), caused by amyloid plaques and tau tangles, primarily affecting memory first
  • Vascular dementia results from reduced blood flow to the brain and often shows stepwise decline
  • Lewy body dementia involves alpha-synuclein deposits and is characterized by fluctuating cognition, hallucinations, and movement problems
  • Frontotemporal dementia primarily affects personality and behavior before memory, most common in people under 60
  • Mixed dementia (two or more types together) is more common than previously recognized
  • Cerebrovascular disease and mini-strokes are the underlying causes of vascular dementia
  • Wernicke-Korsakoff syndrome is caused by thiamine deficiency, often related to alcohol misuse
  • Creutzfeldt-Jakob disease is a rare, rapidly progressive prion disease
  • Huntington's disease is an inherited genetic disorder affecting movement and cognition
  • Parkinson's disease dementia develops when cognitive decline occurs years after Parkinson's motor symptoms
  • Normal pressure hydrocephalus is potentially reversible if caught early and treated with a shunt

In Chapter 4, we'll explore the neuroscience behind neurodegeneration, examining in detail the molecular mechanisms—like amyloid plaques, neurofibrillary tangles, and abnormal proteins—that cause different types of dementia.

Test Your Understanding - Click to expand

Before moving to the next chapter, reflect on these questions:

  1. What are the three hallmark features of Lewy body dementia that distinguish it from Alzheimer's?
  2. How does the progression pattern of vascular dementia typically differ from Alzheimer's disease?
  3. Why is frontotemporal dementia often diagnosed in younger people compared to Alzheimer's?
  4. What makes mixed dementia challenging to diagnose?
  5. Which type of dementia is potentially reversible if caught early, and why?
  6. What is the key difference between Lewy body dementia and Parkinson's disease dementia?

If you can answer these questions, you understand the major differences between dementia types and are ready to learn about the molecular mechanisms underlying neurodegeneration in Chapter 4.