Other Types of Dementia

Vascular dementia refers to a number of dementia syndromes caused by damage to cerebral blood vessels that can limit the oxygen supply and lead to cell death.  Symptoms are often of sudden onset and may follow a stroke.  Sometimes a series of strokes leads to a step-wise deterioration in neuropsychological functions.  This condition is often called multi-infarct dementia.

Fronto-temporal dementias such as Pick’s disease result in more localized brain damage than   SDAT, usually beginning in the frontal lobes.  Initially, personality and social-emotional behavior are more affected than memory.  In late stages, the clinical picture may be indistinguishable from SDAT.

Prion diseases such as Creutzfeldt-Jacob disease are caused by infectious agents, which attack brain tissue.  People with AIDS can also have dementia, typically in the later stages of the illness.

Dementia can also be caused by exposure to toxins such as alcohol and other substances as well as by head trauma with loss of consciousness and hypoxic injury.

Effects of Stress on the Brain and Cognition

The ability to form and retrieve memories associated with terrifying or otherwise stressful events is essential to human survival.  Regions of the brain and central nervous system play a pivotal role in the human stress response.  Deep brain structures forming the limbic system are essential to the modulation of  brain responses to stressful events.

For example, stress has effects on the hippocampus, a seahorse shaped structure deep in the temporal lobe that is essential to the ability to form new memories.  Studies of primates who died accidentally following exposure to severe stress were found to have suffered damage to certain hippocampal cell banks.

Cellular damage is associated with the release of substances called glucocorticoids in these brain regions.  These substances can cause shrinkage of  parts of the neuron, specifically, branching dendrites that form complex connections with other cells to allow for effective thinking and control of behavior.  The effect of these substances often is reflected in deficient spatial memory which can be identified by careful neuropsychological examination.

Reference: La Rue, Asenath-- "Aging and Neuropsychological Assessment", Plenum Press, New York, 1992