Etiology

•Familial types are known but most cases are sporadic.

Epidemiology

• Senile dementia is seen in over 47% of the population over 85 years and increases rapidly after that.

• Alzheimer's disease is the most common senile dementia in patients greater than 65 years old. Alzheimer's disease is seen before 65 years of age and is called presenile dementia. Most familial cases are presenile.

• Since the 85 years of age and older group is increasing rapidly, Alzheimer' disease is becoming an important disease.

Clinical Correlation

•Alzheimer's disease is a devastating disease causing loss of recent memory, followed by old memories and apraxias or inability to carry out a normal procedure such as dressing, eating etc. The patient is finally bedridden with many neurological signs and usually dies of pneumonia, heart attack, or stroke.

•Lifespan with the disease is usually 5 Years after diagnosis but may be 10 years if the patient is otherwise healthy. Toward the end the patient is unable to recognize anyone and may become hostile.