Question – Is Alzheimer’s the only type of dementia?
Answer – Although Alzheimer’s is the most common form of dementia, there are other types of dementias that are also frequently diagnosed. Some of the most common forms of dementia, other than Alzheimer’s, include:
Multi-infarct dementia (MID), or vascular dementia, is a deterioration of mental capabilities caused by multiple strokes (infarcts) in the brain. The onset of MID may be relatively sudden as many strokes can occur before symptoms appear. These strokes may damage areas of the brain responsible for a specific function as well as produce generalized symptoms of dementia.
As a result, MID may appear similar to Alzheimer’s disease. Multi-infarct dementia is not reversible or curable, but recognition of an underlying condition (ie. high blood pressure) often leads to a specific treatment that may modify the progression of that disorder.
Multi-infarct dementia is usually diagnosed through neurological examination and brain scanning techniques, such as computerized tomography (CT scan) or magnetic resonance imaging (MRI), in order to identify strokes in the brain.
Parkinson’s disease (PD) is a progressive disorder of the central nervous system, which affects more than one million Americans. Individuals with PD lack the substance dopamine, which is important for the central nervous system’s control of muscle activity.
Parkinson’s disease is often characterized by tremors, stiffness in limbs and joints, speech impediments and difficulty in initiating physical movement. Late in the course of the disease, some patients develop dementia and eventually Alzheimer’s disease.
Conversely, some Alzheimer’s disease patients develop symptoms of Parkinson’s disease. Medications such as levodopa, which converts itself into dopamine once inside the brain and depreynl, which prevents degeneration of dopamine-containing neurons, are used to improve diminished or reduced motor symptoms in PD patients but do not correct the mental changes that occur.
Huntington’s disease is an inherited, degenerative brain disease, which affects the mind and body. The disease usually begins during mid-life, and is characterized by intellectual decline, and irregular and involuntary movements of the limbs or facial muscles.
Other symptoms of Huntington’s disease include personality change, memory disturbance, slurred speech, impaired judgment and psychiatric problems. Huntington’s disease currently affects more than 25,000 Americans.
The diagnostic process for Huntington’s disease includes an evaluation of family medical history, recognition of typical movement disorders and CT brain scanning. A genetic marker linked to Huntington’s disease has been identified on chromosome 4 and researchers are working on locating the gene itself. Although there is no treatment available to stop the progression of the disease, the movement disorders and psychiatric symptoms can be controlled by drugs.
Creutzfeldt-Jakob Disease (CJD) is a rare, fatal brain disorder caused by a transmissible infectious organism, probably a virus. Early symptoms of CJD include failing memory, changes in behavior, and lack of coordination.
As the disease progresses, usually very rapidly, mental deterioration becomes pronounced, involuntary movement – (especially muscle jerks) appear, and the patient may become blind, develop weakness in the arms or legs, and ultimately lapse into a coma.
The death of CJD patients is usually caused by infections in bedridden, unconscious patients. Like Alzheimer’s disease, a definitive diagnosis of CJD can be obtained only through an examination of brain tissue, usually at autopsy.
Pick’s disease is also a rare brain disorder, which, like Alzheimer’s disease, is usually difficult to diagnose. Disturbances in personality, behavior and orientation may precede, and initially be more severe than, memory defects. Like Alzheimer’s disease, a definitive diagnosis is usually obtained at autopsy.
Normal Pressure Hydrocephalus
Normal Pressure Hydrocephalus is an uncommon disorder which involves an obstruction in the normal flow of cerebrospinal fluid. This blockage causes a buildup of cerebrospinal fluid on the brain.Symptoms of Normal Pressure Hydrocephalus include dementia, urinary incontinence and difficulty in walking.
Presently, the most useful diagnostic tools are neuroimaging techniques (e.g., MRI). Normal pressure hydrocephalus may be caused by any of several factors including meningitis, encephalitis and head injuries. In addition to the treatment of the underlying cause, the condition may be corrected by a neurosurgical procedure (insertion of a shunt) to divert the fluid away from the brain.
Depression is a psychiatric disorder marked by sadness, inactivity, difficulty in thinking and concentration, feelings of hopelessness, and sometimes suicidal tendencies. Many severely depressed patients will have some mental deficits including poor concentration and attention.
When dementia and depression are present together, intellectual deterioration may be exaggerated. Depression, whether present alone or in combination with dementia, can be reversed with proper treatment.
Diffuse Lewy Body Disease
Diffuse Lewy Body Disease (DLBD) is another degenerative brain disorder, now thought to be the second most common type of dementia. Lewy Bodies are small round inclusions that are found within nerve cells.
These Lewy Bodies are found in both P.D. and A.D. However, in Diffuse Lewy Body Disease, pathological features that overlap both A.D. and P.D. Symptoms include cognitive impairments, fluctuation in level of alertness, visual hallucinations, severe motor defects, reduced facial expression, shuffling gate, tremors, rigidity, unsteady gate and balance. These patients may have frequent falls.