Classifying Dementia

You may understand this post better if you start at “What is dementia“.

Before we jump into the types of dementia, please remember that dementia is defined as ” a chronic or persistent disorder of the mental processes caused by brain disease or injury and marked by memory disorders, personality changes, and impaired reasoning.”. There may be several causes for the decline of mental processes. It is important to understand the core causes in order to manage the condition effectively.

There are two primary means of classifying dementia.

1)By location of lesion. (Which part of the brain is affected).

2)By reversibility of deficit.

Cortical and Subcortical Dementia.

The cerebral cortex is the outer surface of the cerebral hemisphere. It has about 20 billion neurons in the human brain which carry out functions such as thinking, remembering, planning, perceiving, producing, understanding and processing information.

The regions of the brain that lie below the cortex are termed “Subcortical“. This include important centers responsible for movement, hormone production, emotions breathing, temperature control etc.

The cortex and the the sub cortical structures constantly communicate with each other to make day to day functioning possible. Dementia can be split into two groups based on which part of the brain is affected.

Cortical DementiaSubcortical Dementia
Alzheimer’s disease.
Vascular dementia.
Frontotemporal dementia.
Creutzfeldt-Jakob disease.
Parkinson’s dementia.
Lewy body dementia.
Huntington’s dementia.
AIDS dementia complex.

Cortical dementia usually present with memory, language and behavioural disturbances while subcortical dementias present with problems in movement. There will be a significant overlap between the two in later more severe stages of the disease.

Continue on to page two to read about reversible and irreversible dementia.