Senile dementia is a major medical problem in the world of today. The change of life style and the control of hypertension, hyperlipemia, hyperglycemia and hyperviscosity of blood do reduce the morbidity rate of apoplexy and vascular dementia; however, with the prolongation of human life-span, senile dementia (Alzheimer's disease) increases year by year. The pathogenesis and control of senile dementia will be the hottly pursued subject of brain science in the next century.
The cause of senile dementia is unknown. At present, senile dementia is regarded as a polygenic disease, and whether and when the disease develops is related to many risk factors. These risk factors seem to influence the expression of regulator genes. Senile dementia is a chronic progressive retrograde affection of the brain. It is marked by memory disorders, changes in personality, deterioration in personal care, impaired reasoning ability and disorientation. Autopsy and biopsy of the brain show encephalatrophy, larger amount of senile cortical plaques and neurofibrillar tangles. The disease begins with the occurrence of amnesia, followed by psychonosema and finally by complete dementia.
Some middle-aged and old people suspect, when their memory is failing, that whether they have had senile dementia. With the increase in age, the quantity of brain cells will decrease gradually, particularly the decrease of

Authors' unit: Guangdong Gaoming Medical and Medicinal Institute of Encephalopathy, 2 Heping Lane, Cangjiang Road, Hecheng District, Gaoming, Guangdong 528500
brain cells in hippocampus of cerebral cortex. The physiological function of hippocampus is related to memory, the hypomnesis of old people, a normal physiological phenomenon, involves mainly the process of memory repetition. Old people often fail to pick up information from memory center freely, for examples, they cannot recall exactly the name of an acquaintance, cannot remember a Chinese character, but can recall by prompting them what they forgot. The dysmnesia in senile dementia, however, is characterized by the difficulty in remembrance, that is, new information cannot be stored in mind with the result that the sufferer cannot learn new knowledge, by deterioration from recent amnesia to retrograde amnesia, and by dyscalculia, disorientation, aphasia and impaired reasoning ability.
With the popularization of CT scanning and MRI examination of the head, the question is raised whether encephalatrophy is senile dementia or not. The weight of human brain is about 1 300 g. Form 20 years to 90 years of age, the weight of human brain will gradually reduce by 10% or so and at the same time the ventricles of brain will enlarge by 3 or 4 times. The clinical significance of these changes is hard to judge, because there is no good correlation between the weight of brain, the size of brain ventricles and intelligence. The amount of brain cells, the compensatory mechanism of cerebral cortex and the plasticity of dendrites of brain cells are all closely related to intelligence. Senile dementia is certainly accompained by encephalatrophy, the presence of encephalatrophy does not necessarily indicate the presence of dementia.
Senile melancholia is sometimes manifested as symptoms similar to those of dementia such as sluggishness with fewer motions, retardation of thought, hypologia and hypomnesis, but the obvious mood depression, anxiety, definite time of onset, undulant state of illness and good response to anti-depressive treatment in senile melancholia should distinguish this condition from senile dementia.
The diagnosis of senile dementia can be made based on case history, results of physical and laboratory examinations and the elimination of dementia to which other etiological factors may be attributed. For a confirmed diagnosis, pathological examination of brain tissue is indicated. (1) Dementia can be confirmed by inquiry about detailed case history and neuropsychological test; (2) the patient has no disturbance of consciousness; (3) the patient's age is, for the most part, more than 60 years; (4) disorder of cognitive function is undergoing slow exacerbation; (5) the patient has no systemic lesions or other diseases that affect the functioning of the brain; and (6) serum apolipoprotein E4 (Apo-E4), label of senile dementia, is positive in most cases. How to make an early diagnosis of senile dementia remains a medical problem in the world of today.
Although senile dementia belongs to a polygenic disease, whether it develops or not depends upon the complex mutual interaction between genetic factors and environmental factors. The elimination of various risk factors and the maintenance of stability of internal and external environments of the organism are the effective route of preventing senile dementia. These include: (1) regular life, sound sleep, and adequate manual and mental labour; (2) rational diet, eating more sea fishes and bean products, one egg per day; (3) mental health, emotional optimism, and wide interests; (4) no smoking and drinking a little; and (5) preventing brain trauma, reducing infections and contaminations of environment and food. Persevering accomplishment of these requirements will lead to invigorating the brain and strengthening the body.
Up to now, there have been no definitely effective therapies or medicines for treating senile dementia in modern medicine. In traditional Chinese medicine, senile dementia is believed to be the result of deficiency of the kidney-essence due to agedness and failure of primordial energy to nourish the brain with the results that reservoir of marrow is hollow with phlegm stagnancy and blood stasis, that the brain is blocked and loses nourishment and that cognition is failing. One of the authors (Dr. Li Zizhong) developed a series of Chinese medicinal prescriptions after more than 20 years' study with great concentration based on the principles of tonifying the kidney to replenish essence, nourishing the heart to invigorate the spleen, promoting blood circulation to remove blood stasis and eliminating phlegm for resuscitation by using modern biological techniques. It was demonstrated clinically and experimentally that these Chinese medicinal prescriptions have definite therapeutic effectiveness in treating various diseases that affect the functioning of the brain, including dementia. After treatment, the patients' cognitive function was improved, their psychonosema was controlled and their personality defects were restored. Serological examination and neurobiochemical, physiological and molecular biological studies of Chinese drugs showed that the Chinese medicinal prescriptions do promote proliferation of nerve cells, inhibit apoptosis of nerve cells and bidirectionally regulate neurotransmitters and nerve conductive pathways in the brain.
Senile dementia is both a severe medical problem and a wide social problem. Treatment of senile dementia with traditional Chinese medicine will certainly shine with dazzling splendour.