Subcortical dementia

Subcortical dementia is a type of dementia characterised by slowness of mental processing, forgetfulness, impaired cognition, apathy, depressive symptoms (such as anhedonia, negative thoughts, loss of self-esteem and dysphoria), loss of social skills and extrapyramidal disorders.[1]

Disorders, such as CADASIL, cerebral palsy and atypical parkinsonism (Huntington disease, encephalitis lethargica, progressive supranuclear palsy, corticobasal degeneration, multiple system atrophy, chronic traumatic encephalopathy, Lytico-Bodig disease, tardive dyskinesia and FTDP-17) that result in subcortical dementia have changes that involve primarily the thalamus, basal ganglia, and related brain-stem nuclei with relative sparing of the cerebral cortex. It affects arousal, attention, mood, motivation, language, memory, abstraction, social skills (especially empathy), extrapyramidal functions, and visuospatial skills. Additionally, damage to the basal forebrain can cause amnesia and psychotic disorders. Subcortical dementia differs from other dementia such as frontotemporal dementia and Alzheimer's where prominent cerebral cortical involvement produces aphasia, amnesia, agnosia, and apraxia.[1]

In most kinds of dementia there is widespread degeneration in the cerebral cortex – such as the plaques and tangles which are the hallmark of Alzheimer's disease. In other kinds of dementia, there is targeted damage to regions lying under the cortex, giving rise to the category known as "subcortical dementias".

As a general rule the earliest symptoms in "cortical" dementia include difficulty with high-level behaviors such as memory, language, problem-solving and reasoning – functions associated with the cerebral cortex.

However, in "subcortical" dementia these high-level behaviours are less affected.[2]