Dementia is a broad term to describe related conditions causing an impairment in cognition that is significant enough to interfere with daily living and independence. Subcortical dementia is a type of dementia that starts in the region known as the subcortex, which is located under the cortex of the brain.
The subcortical region comprises white matter. White matter consists of nerve fibers called axons, which are extensions of neurons, or nerve cells. A covering called myelin surrounds these nerve cells, giving the white matter its color.
This region creates neural connections between cortical and subcortical regions in the brain. It serves as the basis of the neural network and plays an important role in brain function.
Some evidence suggests that white matter deteriorates naturally over time. However, the limited ability to analyze the area makes it difficult for scientists to assess this fully.
This article explains what subcortical dementia is and how it differs from cortical dementia. It also looks at the symptoms, causes, and treatment of this condition.
What is it?
The Alzheimer’s Society, a charity in the United Kingdom, states that experts believe subcortical dementia to be the most common type of vascular dementia. Vascular dementia occurs as a result of reduced blood flow to the brain or ischemic stroke.
Subcortical dementia is a type of vascular dementia that begins in the region of the brain called the subcortex.
The subcortex comprises white matter and includes several regions, including the striatum, the globus pallidus, and the substantia nigra. It is responsible for developing neural connections between the cortical and subcortical regions of the brain.
Vs. cortical dementia
The brain is divided into several parts and sections. Each section controls certain aspects of a person’s movements, emotions, thinking, and other functions associated with the brain.
Different conditions can affect various areas of the brain, resulting in different symptoms. Cortical dementia describes forms of dementia that affect the cerebral cortex, which is located directly above the subcortex.
Types of cortical dementia include:
- Lewy body dementia
- Alzheimer’s disease
- posterior cortical atrophy
- frontotemporal lobe dementia
- Creutzfeldt-Jakob disease
A person with a cortical form of dementia, such as Alzheimer’s disease, often experiences symptoms that include:
- trouble remembering information
- difficulty with mental processing
- changes in mood and behavior
- periods of confusion
Symptoms
Subcortical dementia is a type of vascular dementia, which can cause:
- difficulty performing certain tasks, such as paying bills
- difficulty following instructions
- difficulty learning new information and routines
- forgetting current or past events
- challenges with language, such as finding the right word
- challenges with reading and writing
- misplacing items
- getting lost on familiar routes
- changes in sleep patterns
- losing interest in people
- hallucinations
- delusions
- poor judgment
- changes in mood, personality, and behavior
- an inability to perceive danger
The Alzheimer’s Society notes that the symptoms of subcortical dementia are more consistent.
Early loss of bladder control is common, and people may be weaker on one side of the body. Other symptoms include:
- being more likely to fall over
- difficulties pronouncing words
- a lack of facial expressions
Causes and risk factors
The Alzheimer’s Society notes that subcortical dementia develops due to a disease that affects the very small blood vessels, called small vessel disease. The walls of the blood vessels thicken, becoming stiff. This results in a reduced blood flow.
Small vessel disease can also damage the axons, or nerve fibers, in the brain, called white matter.
The National Institute on Aging states that researchers are currently researching how these changes in the brain are connected to the development of dementia. However, there appear to be strong associations between cardiovascular disease, cerebrovascular disease, and dementia.
Certain factors can make the development of dementia more likely. These risk factors include:
- high blood pressure
- advanced age
- smoking
- uncontrolled diabetes
- consuming too much alcohol
- having a close family member with dementia
Treatment
There is currently no standard of care for cases of vascular dementia that affect the subcortical region.
However, a person can take steps to help prevent further damage to their brain’s arteries. Preventive treatments for blood vessel damage related to vascular dementia may help slow its progression.
A doctor may prescribe:
- medications to treat high blood pressure
- medications to treat high cholesterol
- anticoagulants or low dose aspirin to reduce the risk of blood clots
They may also prescribe:
- acetylcholinesterase inhibitors, such as donepezil (Aricept), galantamine (Reminyl), or rivastigmine (Exelon)
- memantine (Namenda)
- cholinesterase inhibitors
A person may also need to stop taking medications that can worsen cognitive decline, such as anticholinergics.
A person with subcortical dementia may find the following therapies beneficial:
- cognitive stimulation therapy, which involves taking part in activity sessions to keep the mind active
- cognitive rehabilitation
- talking therapies
- cognitive behavioral therapy
- occupational therapy
- music and creative arts therapies
Diagnosis
There is no single test to diagnose dementia. A doctor will make a diagnosis based on:
- a person’s medical history
- a physical examination
- blood tests to rule out other causes
- mental ability tests
They may also order a CT or MRI scan. These imaging tests can help distinguish between vascular dementia and some other types of dementia.
People may find it beneficial to bring a person they trust to the doctor’s appointment.
Outlook and life expectancy
There is no cure for subcortical dementia. It is a progressive condition that will get worse over time.
A 2022 article states that those who receive a vascular dementia diagnosis typically have a shortened life expectancy.
A person should speak with a doctor about their individual outlook.
Summary
Subcortical dementia develops in the region of the brain called the subcortex. This is located underneath the cortex of the brain.
Subcortical dementia is the most common type of vascular dementia. It occurs when diseases affect the small blood vessels in the brain. The nerve fibers in the brain, called white matter, also become damaged.
There is no cure for subcortical dementia, and it is a progressive condition that can result in a shortened life expectancy. However, treatments can help slow the progression of the disease.
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