Dementia is Not Just Alzheimer's!

Dementia is a condition caused by a number of different diseases. Many people equate dementia with Alzheimer's disease, but they are not synonymous. It is true however, that Alzheimer's is one of dementia's major causes.

Dementia is a global impairment of cognitive ability that interferes with normal activities of daily living. Loss of memory is the hallmark of dementia. Impaired executive functioning (i.e., inability to plan, organize and implement a task) is another prime characteristic of dementia. Other characteristics include problems with language, spatial orientation, and changes in behavior.

Dementia is what we once called senility. It is not a normal part of aging though the diseases that produce it are much more common in the elderly.

Statistics for the causes of dementia vary depending on the population surveyed and the criteria used for the diagnosis of different types. At times, causes may not be clear-cut, and in many cases, more than one pathologic process may be at work. The prevalence of different forms of dementia varies in different countries. Dementia also seems to occur more frequently in urban environments.

Overall, it is estimated that Alzheimer's pathology is present in about 50-75% of all dementias. Major symptoms of Alzheimer's disease are memory impairment, language dysfunction, visual-spatial deficits, impaired executive function, and behavior disturbance.

Fronto-temporal dementia (or Pick's disease) may represent 5-10% of cases. Unlike many dementias, memory ability remains fairly intact until the disease is advanced. There are felt to be two major clinical subdivisions of this dementia, frontal lobe variant and temporal lobe variant. In the frontal lobe variant, behavioral abnormalities predominate along with changes in personality and social conduct. These persons may show poor impulse control, rudeness and use foul language in situations where it is uncalled for. In the temporal lobe variant, language function and speech are affected with behavioral problems less prominent. Initially, these persons may have difficulty finding words, naming objects and have difficulty expressing themselves as well as understanding what has been said to them. Sometimes only nonsensical phrases are spoken. In most cases, verbal output is progressively reduced, and eventually the affected individuals become mute.

Dementia with Lewy bodies and Parkinson's disease dementia represent about 15-20% of cases. These two conditions have similar disease processes though different parts of the brain are predominantly affected by each entity. Lewy bodies are present in the neurons in both illnesses and the clinical pictures include the motor finding of Parkinson's disease and cognitive decline. However, in Dementia with Lewy bodies, intellectual impairment is evident early on, whereas in Parkinson's it occurs later.

Fluctuation in cognitive ability with variation in attention and alertness, recurrent visual hallucinations, and motor features of Parkinson's disease are the signal features of Dementia with Lewy bodies. The same pattern of cognitive impairment seen in Dementia with Lewy bodies also occurs in Parkinson's disease dementia though hallucinations may be less frequent. Difficulties with memory and executive functions are prominent. Speech impairment is often a major feature and usually because of motor dysfunction. Visuo-spatial problems are also seen frequently.

Vascular dementia may represent about 20-25% of cases. Most older people have some vascular changes in the brain though the degree of involvement varies. When dementia from any cause occurs in the elderly, it is likely that cerebrovascular disease is playing some role. A more accurate label for many cases may be mixed dementia.

Vascular dementia has also been called multi-infarct dementia and post-stroke dementia. The classic description is of a stepwise deterioration in cognitive function following stroke, but this is not always the case. There may be a slow progressive decline in cognitive ability. Strokes may be silent and without sudden changes in the individual. Also, the parameters of cognitive dysfunction depend on the location and severity of strokes.

There are many other different disease processes that produce dementia. Some of these less common conditions include normal pressure hydrocephalus, Creutzfeldt-Jakob disease, progressive supranuclear palsy and Huntington's disease. Infectious causes of dementia include syphilis, Lyme's disease, and AIDS. A metabolic problem like thyroid deficiency (hypothyroidism) is a reversible cause of dementia that is important to rule out in persons who have cognitive impairment. Autoimmune diseases like multiple sclerosis and lupus can also progress to dementia.

To summarize, dementia is a condition caused by a number of different diseases or pathological conditions, and many times there may be multiple causes or explanations for cognitive declines observed. When dementia is suspected, see your primary care physician who can refer you to a geriatrician or a neurologist to assist with diagnosis and treatment of symptoms. Your physician may also refer you to a psychologist who specializes in neuropsychological testing. Information obtained from neuropsychological testing can help to determine if impairment exists, its severity, whether the pattern of impairment within the context of the individual's history suggests a diagnosis, and what are the real life consequences of this impairment. Through education and psychological counseling, the individual and his/her family can learn to cope more effectively with losses in cognitive and physical functioning and with emotional and behavioral changes.

Catherine C. Cherpas, Ph.D.
Counseling Psychologist