Subcortical dementias affect the deeper regions of your brain. Often due to conditions like Parkinson’s or Huntington’s, subcortical dementias cause symptoms like slowed thinking, memory loss, and personality changes.

Dementia is a broad term that refers to a permanent decline in your memory, thinking, reasoning, and self-care. It occurs when your brain cells, also known as neurons, can’t function properly and start to die off. The signs and symptoms of dementia vary based on which parts of your brain are affected.

Subcortical dementias affect structures deep inside your brain, such as the basal ganglia and the thalamus. These regions are involved in sensory processing, motivation, emotional regulation, and many other cognitive functions.

Some neurological conditions, like Parkinson’s disease, can lead to subcortical dementia. Keep reading to learn more about the causes, symptoms, and treatment options for subcortical dementia types.

Subcortical dementias affect your subcortical structures, which are located under your cerebral cortex. Structures in this region include gray and white matter in the innermost part of your brain.

Put another way, if your brain is like an avocado, the cortex is the green part, and the subcortical region is the pit.

Your cerebral cortex consists of the frontal, temporal, parietal, and occipital lobes. Cortical dementias such as Alzheimer’s disease (AD) and frontotemporal dementia (FTD) affect your frontal lobe and often other lobes as well.

But cortical dementias can also affect subcortical regions, and it may be difficult to distinguish between the two types since they cause similar symptoms.

The authors of a 2018 study report that amyloid plaques, a hallmark of AD, eventually affect your amygdala, putamen, and caudate nucleus in the subcortical region. This is a development linked to further cognitive decline.

Similarly, the authors of a 2021 review used brain imaging studies to show that subcortical structures also play a role in the development of FTD.

Subcortical structures

The subcortical region of your brain contains several structures with varying functions. These include the:

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Subcortical dementia can cause a wide range of symptoms. But the symptoms vary according to your underlying condition and which brain structures are affected.

Some symptoms associated with subcortical dementia include:

Subcortical dementias usually occur alongside movement symptoms, such as:

  • tremors
  • difficulty walking
  • muscle contractions

People with subcortical dementia usually have one or more of the conditions listed above. But the mechanism that leads to dementia is slightly different for each condition.

In vascular dementia, for example, tiny blood vessels in your brain stiffen, making it hard for blood to reach subcortical structures such as your amygdala. This can cause small strokes throughout the subcortical region, leading to atrophy and causing dementia symptoms.

In Parkinson’s disease, a protein called alpha-synuclein forms large clusters called Lewy bodies to accumulate in subcortical structures, such as your substantia nigra. Lewy bodies disrupt brain function and cause neurons to malfunction or die altogether.

Your age, genetics, and sex can all play a role in the development of dementia. According to a 2020 report, some other study-indicated risk factors include:

You might also be at an increased risk of subcortical dementia if you have another neurodegenerative condition.

For example, according to a 2022 review, approximately 26% of people who receive a diagnosis of Parkinson’s disease also develop dementia.

Subcortical dementia isn’t a diagnosis in itself. It’s a general term for dementia that affects a particular region of your brain.

You won’t know if you have subcortical dementia unless a doctor or healthcare professional does a brain scan to see which regions of your brain are affected. Some brain scans for dementia include MRIs, CT scans, and PET scans.

If you have symptoms of any type of dementia, a doctor will try to identify the cause. The diagnostic process will include:

  • a physical examination
  • a review of your medical history
  • questions for you or a close family member about your symptoms

Other common tests for dementia include lab tests and cognitive assessments.

The treatment for subcortical dementia depends on the underlying cause.

For example, if you have subcortical vascular dementia, a doctor will suggest treatments to help improve blood flow to the affected areas of your brain. These could include medications for high blood pressure or specific lifestyle changes.

Although most conditions that lead to subcortical dementia can’t be cured, treatments can often help stall disease progression.

It’s important to get treatment right away if you’re experiencing symptoms of any type of dementia.

If you have subcortical dementia, many factors can influence your life expectancy. These include the underlying condition, your age, and your overall health.

For instance, the median life expectancy for someone with vascular dementia is around 3–5 years after symptoms start, according to a 2023 review.

In a 2017 study, people with Parkinson’s disease dementia died on average 2.5 years earlier than people with Parkinson’s disease alone.

Subcortical dementia occurs when structures in your brain’s subcortical region become impaired or break down. This can lead to symptoms such as slowed thinking, limited judgment, and forgetfulness. These symptoms aren’t unique to subcortical dementia and can be due to other forms of dementia.

Subcortical dementia isn’t a diagnosis on its own. It’s typically due to an underlying neurological condition. Some of the more common causes include vascular dementia, Parkinson’s disease, and Lewy body dementia.

If you suspect you or a loved one has dementia, talk with a doctor to understand your next steps.