Understanding Dementia: Types, Symptoms, and Impact on Lives

Alzheimer’s disease is the most frequently diagnosed form of dementia, but it represents just one aspect of a more complex landscape of neurodegenerative diseases. Most individuals with dementia display a combination of several types of these disorders, which can include the characteristic amyloid plaques and tau tangles associated with Alzheimer’s, as well as vascular damage indicative of vascular dementia, and toxic protein aggregates seen in Lewy body dementia, frontotemporal dementia, and LATE. According to Dr. Costantino Iadecola, a professor of neurology at Weill Cornell Medicine, “If you look at the old people with dementia, what do they have? Well, they have a little bit of everything.”

While current treatments cannot halt or reverse dementia’s progression, obtaining a precise diagnosis is crucial for managing symptoms and understanding the disease’s trajectory. Here is an overview of the primary types of dementia, their effects on the brain, and their associated symptoms.

Vascular Dementia: The Silent Progression

Vascular dementia stands as the second most prevalent form of dementia. It often develops after a significant stroke or multiple smaller strokes, but more commonly arises from chronic damage to the brain’s smaller blood vessels. Such damage typically affects the white matter of the brain, which consists of insulated nerve fibers responsible for transmitting signals between neurons.

When blood flow becomes obstructed, brain cells are deprived of essential oxygen and nutrients. Silvia Fossati, a professor of neural sciences at Temple University’s Lewis Katz School of Medicine, explains, “When blood flow to the brain is disrupted, the brain cells are deprived of oxygen and nutrients.”

Common symptoms of vascular dementia include general cognitive and physical slowing, difficulty with decision making, problem-solving, and task execution. Poor cardiovascular health, particularly high blood pressure, represents the most significant risk factor. Individuals with a history of heart attack or stroke often show symptoms of vascular dementia. MRI scans can confirm the diagnosis by highlighting white matter damage. Despite the irreversibility of symptoms once brain cells are harmed, vascular dementia is more preventable than other dementia forms. Dr. Iadecola advocates for maintaining healthy blood vessels as the best strategy for prevention.

Lewy Body Dementia: A Multifaceted Challenge

Lewy body dementia presents a diverse range of symptoms, impacting both cognitive function and physical health. Dr. Sudha Seshadri, founding director of the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, notes that this condition affects not just the brain but also the peripheral nervous system.

Symptoms may include cognitive impairments, such as challenges with executive functioning and visual-spatial difficulties. Patients often experience vivid visual hallucinations and a variety of physical issues, including constipation and balance problems. The overlap of symptoms with Parkinson’s disease, such as tremors and muscle rigidity, arises from both conditions being linked to the misfolded protein alpha-synuclein. Diagnosis relies heavily on observed symptoms, which can vary significantly among patients, leading to underdiagnosis of Lewy body dementia according to Dr. David Irwin, an associate professor of neurology at Penn Medicine.

Frontotemporal Dementia: Early Onset and Dramatic Changes

Frontotemporal dementia (FTD) is less common than other dementia types and typically manifests earlier in life, often in individuals in their 40s to 60s. This form targets the brain’s frontal lobe, leading to significant cognitive symptoms, including challenges in executive functioning and planning. Dr. Irwin notes that these difficulties may become apparent when individuals struggle with managing finances or organizing tasks.

Personality changes are also prevalent, with some individuals exhibiting uninhibited or impulsive behaviors, while others may become apathetic or emotionally detached. FTD is frequently misdiagnosed as a psychiatric disorder due to its behavioral symptoms. Dr. Winston Chiong, a professor of neurology at the University of California, San Francisco, explains that many core symptoms are often attributed to depression or life events.

LATE: A Newer Understanding of Dementia

LATE, or limbic-predominant age-related TDP-43 encephalopathy, represents a relatively recent addition to the dementia classification. First identified approximately 20 years ago, LATE is characterized by the presence of toxic clusters of the protein TDP-43 in the brains of individuals displaying Alzheimer’s-like symptoms. Dr. Peter Nelson, a professor of pathology at the University of Kentucky College of Medicine, states that around one-third of individuals in their 80s and 90s exhibit signs of LATE.

The hippocampus is primarily affected, leading to memory loss as the most common symptom. LATE often progresses slowly and is considered relatively benign when occurring independently. However, when occurring alongside Alzheimer’s, it can result in a more rapid and severe clinical course, encompassing anxiety, depression, hallucinations, and delusions. Diagnosis remains challenging, as there is no blood test for TDP-43; physicians must rely on symptomatology and exclude other dementia forms. Currently, the first clinical trial for LATE treatment is underway.

Understanding the nuances between these different types of dementia is essential for improving diagnosis and management strategies. As research progresses, the hope is to find effective treatments that can enhance the quality of life for those affected by these complex conditions.