Understanding the Different Types of Dementia

Dementia is an umbrella term neurologists use to describe a range of conditions that severely affect memory, thinking, and social abilities. While Alzheimer's disease (AD) is the most common type of dementia, accounting for 60-80% of cases, there are other types of dementia that people can develop as​​ they age. It's essential to understand the differences among these types of dementia, as each has unique characteristics and treatment approaches.

Types of Dementia

Alzheimer's disease (AD) is the most common form of dementia caused by the accumulation of abnormal amyloid and tau proteins. The fundamental cognitive deficits stem from impaired ability to learn and retain new information (immediate memory). Symptoms may include confusion, difficulty with decision-making and problem-solving, and changes in behavior and mood.  While AD typically affects individuals over the age of 65, early-onset Alzheimer's can also occur in individuals as young as 40.  This early-onset form of the disease presents unique challenges and may have a different course of progression compared to late-onset AD.

Frontotemporal dementia (FTD) is a neurodegenerative disease that affects the frontal and temporal lobes of the brain, which are responsible for personality, behavior, and language. Initial symptoms can be variable and include difficulties in language processing, social connection, and emotional regulation. Gradual changes in behavioral regulation, including impulsivity, along with language difficulties like trouble finding words and using the wrong ones, may lead observers to mistakenly believe the patient has a psychiatric issue rather than a neurological or cognitive disorder, especially in the early stages of the disease. There is currently no cure for FTD, but medication can be used to manage symptoms, such as antipsychotics or antidepressants to help with mood-related symptoms. One significant difference between FTD and AD is the age of onset. FTD typically occurs in individuals between ages 40-65, while AD usually develops after age 65. Brain imaging studies show in FTD there is more significant atrophy (shrinkage) in the frontal and temporal lobes compared to other areas of the brain, while in AD, there is more widespread atrophy throughout multiple brain regions.

Lewy Body dementia (LBD) is a type of dementia that shares similar symptoms with Alzheimer's disease, such as memory loss, confusion, and trouble with daily tasks. There are, however, some critical differences between LBD and AD, namely the presence of Lewy bodies in the brain. The microscopic changes observed in the brains of people with AD are called “plaques and tangles'', which are composed of deposits of the proteins amyloid and tau, respectively.  Similarly, Lewy bodies are composed of a misfolded protein known as synuclein. Though approximately 40% of AD patients also have Lewy bodies present in the brain, the clinical presentation of LBD differs from AD. Memory loss and cognitive decline tend to be the earliest and most prominent symptoms of AD, but in LBD, cognitive decline can occur alongside other symptoms, such as visual hallucinations, movement problems, and fluctuations in alertness and attention. Both LBD and AD are influenced by age, but genetics have a more pronounced impact on AD, whereas environmental factors may contribute to LBD. Correct diagnosis is key, as medications prescribed for AD could potentially worsen symptoms in individuals with LBD.

Vascular dementia is mediated by disease of blood vessels resulting in multiple small strokes. It's managed by treating conditions that impair blood vessel integrity (such as elevated blood pressure and diabetes, and by enhancing blood flow with medications such as antiplatelet medications. The symptoms of vascular dementia tend to appear suddenly and progress in a step-like pattern, with periods of stability followed by sudden declines in cognitive function. Additionally, the symptoms of vascular dementia often include difficulty with movement and coordination as well as problems with language and communication, symptoms that are less common in the early stages of AD. Possibly, the most significant difference between vascular dementia and AD is that individuals with vascular dementia are at a higher risk for experiencing strokes or mini-strokes (also known as transient ischemic attacks), which can further damage brain cells and worsen cognitive function.

How Can You Participate?

Remember, there are no definitive cures for Alzheimer's disease and dementia, but early detection and intervention can significantly improve the quality of life for those living with dementia and their loved ones. By educating oneself about the disease and supporting those affected by it, we can create a more informed and compassionate society that is better equipped to help those affected by Alzheimer's disease. Those interested can consult their primary healthcare providers, reach out to ATRI, or search for ongoing trials in their area.