What are the types of dementia?

From the Guidelines

Dementia is an umbrella term for over 100 different neurodegenerative conditions, with the most common types being Alzheimer disease, vascular dementia, Lewy body dementia, frontotemporal dementia, and mixed dementia. The types of dementia can be broken down into:

• Alzheimer disease, which is the most common form
• Vascular dementia, resulting from reduced blood flow to the brain often following strokes or small vessel disease
• Lewy body dementia, involving abnormal protein deposits in the brain, causing visual hallucinations and movement problems
• Frontotemporal dementia, typically affecting younger individuals (45-65) and primarily impacting behavior and language
• Mixed dementia, involving multiple types occurring simultaneously, most commonly Alzheimer's with vascular dementia
• Other less common forms, including Parkinson's disease dementia, Huntington disease, and Korsakoff disease, as noted in the study published in Ca-A Cancer Journal for Clinicians 1. The prevalence of dementia is estimated to be around 4.7% to 8.7% in people aged 60 years and older, with the number of people living with dementia projected to increase to 152 million by 2050, according to the study 1. Key risk factors for dementia include lifestyle behaviors such as smoking, physical inactivity, and excessive alcohol consumption, as well as associated illnesses like midlife obesity, diabetes, and hypertension, which overlap with cancer risk factors, as discussed in the study 1. Early diagnosis and treatment are crucial, as approaches vary by type, and controlling underlying conditions such as blood pressure and diabetes is essential in managing vascular dementia, while antipsychotics may be necessary for Lewy body dementia but should be used with caution, as highlighted in the context of dementia care 1.

From the Research

Types of Dementia

• The most common forms of late-onset dementia are:
  • Alzheimer's disease
  • Dementia with Lewy bodies
  • Vascular dementia
  • Frontotemporal dementia 2, 3
• These types of dementia are characterized by the aggregation of misfolded proteins and cerebrovascular disease, with mixed neuropathologies frequently detected in the brains of older people with dementia 2
• Alzheimer's disease is the leading cause and prototypical form of dementia, presenting insidiously and causing progressive cognitive impairment with increasing severity over a period of years 3
• Vascular dementia is the second most common form of dementia and often co-occurs with other progressive cognitive disorders 3
• Lewy body dementias encompass Parkinson disease dementia and dementia with Lewy bodies, which have similar features and are differentiated primarily by the order of motor and cognitive symptom onset 3
• Frontotemporal dementias occur earlier than other forms of dementia, progress rapidly, and often have a genetic component 3

Biomarkers and Diagnosis

• Biomarkers are objectively measurable indicators of normal physiology, pathological processes, or response to an intervention, and are limited for dementia diagnosis and prognosis 4
• Current research is progressing toward clinical use of biomarkers in dementia diagnosis and prognosis, and for monitoring new disease-modifying therapeutics 4
• Plasma extracellular vesicle size and concentration have been found to be altered in Alzheimer's disease, dementia with Lewy bodies, and frontotemporal dementia, and may be a common molecular pathway underlying neurodegenerative dementias 5

Causes and Patterns of Dementia

• The burden of dementia continues to increase as the population ages, with no disease-modifying treatments available 6
• Dementia risk appears to be decreasing, and progress has been made in understanding its multifactorial etiology 6
• The 2018 National Institute on Aging-Alzheimer's Association (NIA-AA) research framework for Alzheimer's disease defines AD as a biological process measured by brain pathology or biomarkers, spanning the cognitive spectrum from normality to dementia 6