Dementia designates a group of age-related neurodegenerative conditions. It is characterized by at least two of its many clinical symptoms: memory loss, deterioration in receptive and expressive language skills, altered perception or difficulty reasoning. Affected individuals will often experience dramatic changes in personality or behavior as well. Psychiatric problems involving apathy, depression, agitation or psychosis occur in 25 to 40 percent of cases. According to the National Institute of Neurological Disorders and Stroke, the type of dementia symptoms people show depends on the nature of the underlying condition they have and the brain areas affected.
Alzheimer's Disease
Alzheimer's dementia results from damage to areas of the brain instrumental for processing information and maintaining new knowledge. These brain regions undergo damage because accumulating deposits of toxic proteins hamper the ability of nerve cells to communicate. Alzheimer's represents the quintessential progressive dementia syndrome. Over time, people with the condition are thrust into a vegetative state, losing all mental capabilities and sense of self. Drugs such as donepezil (Aricept) and memantine (Namenda) might slow the disease, but not cure it.
Vascular Dementia
Vascular dementia--the second most prevalent dementia condition--materializes after injury to blood vessels in the brain, most commonly after stroke. Unlike Alzheimer's disease, vascular dementia does not necessarily get worse over time. The level of cognitive impairment and the kind of brain functions impacted will depend on the extent of trauma provoked by the original stroke and whether additional strokes take place. People who develop vascular dementia can maintain normal personality and behavioral affect.
Lewy Body Dementia
Lewy body dementia (LBD), a progressive disorder, occurs randomly in individuals without a family history. It results from degeneration in areas of the brain important for planning and executing movement. Like Alzheimer's, LBD involves the buildup of toxic protein masses. While people with the condition will show cognitive and psychiatric problems overlapping with Alzheimer's, they will also experience Parkinsonian-like motor disturbances, including muscle rigidity and an abnormal pitter-patter or shuffled walking gait. The life expectancy after initial diagnosis is 7 to 8 years.
Huntington's Disease
Huntington's disease, caused by a hereditary mutant gene, results in widespread nervous system pathology, particularly in deep brain regions collectively known as the basal ganglia. Beyond progressive deficits in general intellectual function and psychological health, affected individuals will experience uncontrollable twisting movements that drive the body into dance-like motions or "chorea." Although the disease course proves devastating, patients with Huntington's can remain aware of their surroundings and exhibit appropriate emotions.
