The Differences Between Cortical and Subcortical Dementia

Why the Physical Area of the Brain Affected by Dementia Matters

Researchers Study Cortical and Subcortical Images of the Brain
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All types of dementia, also known as major neurocognitive disorder, cause impairments in memory, reasoning, and judgment. Depending on which part of the brain is suspected as the primary location of the dementia, the type of dementia may be classified as either cortical or subcortical. Cortical and subcortical refer to areas of the brain.

Cortical or Subcortical?

While some physicians don't use these classifications of cortical or subcortical often, others find some value in categorizing the types of dementia into these groups based on the initial primary location of damage in the brain.

Whichever area of the brain (cortical or subcortical) that is affected will typically demonstrate more physical changes initially, such as atrophy (shrinkage). However, as dementia progresses, the symptoms and effects of both classifications of dementia begin to affect multiple areas of the brain.

Often, the classification of a dementia as cortical or subcortical is less helpful than actually determining the specific type of dementia present. This is because each type of dementia has its own expected set of characteristics, symptoms and prognosis.

Cortical Dementia Defined

The cortex of the brain (the word cortical refers to the cortex) is the part most people are familiar with, at least when it comes to appearance. The characteristic twists and turns of the outer layers play an important role in processing information and in functions such as language and memory.

Cortical dementia is typically associated with the brain's gray matter.

When these outer layers are affected, which is the case with Alzheimer's, frontotemporal dementia, Binswanger's disease and Creutzfeldt-Jakob disease, there are problems with memory, the inability to find the right words and in understanding what others are saying (aphasia).

Subcortical Dementia Defined

As the term suggests, these are dementias believed to initially affect structures below the cortex (sub means below) and are more associated with the brain's white matter.

 Huntington's disease, Parkinson's dementia, and AIDS dementia complex are three examples of conditions classified as subcortical dementia.

It is more common to see changes in personality and a slowing down of thought processes in subcortical dementias. Language and memory functions often appear largely unaffected in the earlier stages of these dementias.

Treatment and Management

Treatments and management of dementia generally have focused most on Alzheimer's disease since it's the most common cause of dementia. These medications are sometimes used to treat other kinds of dementia as well, although they are FDA-approved specifically for Alzheimer's. 

Non-drug approaches can also be helpful in treating dementia. Physical exercise, diet and mental activity have all demonstrated benefits in research for those living with a variety of dementias, whether cortical or subcortical.

Prognosis

The prognosis of cortical and subcortical dementias varies significantly. Several different types of dementia fall into these categories, and progression is affected by a multitude of factors. Age of onset, general health and other medical challenges can all affect prognosis and life expectancy.

Sources:

International Journal of English Language Education. 2013. Volume 1, No. 2. Cortical and Subcortical Dementias: A Psychoneurolinguistic Approach.

Neurobiology of Aging. 2015 Apr;36(4):1743-50. Progressive cortical thinning and subcortical atrophy in dementia with Lewy bodies and Alzheimer's disease

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