1、 Memory loss

What is memory loss?

Memory is the reappearance of past experience, which includes four basic processes: recollection, retention, recognition and recollection. Memory loss is the general decline of the above four processes. Those who are light show that their memory of recent events is weakened, such as forgetting the book they just read and the people they have just met. When it is serious, it will be far away from memory, such as can not recall their own learning experience and so on. Memory impairment refers to mild cognitive impairment (MCI) in the elderly, including patients with mild memory or cognitive impairment but without dementia. The onset of MCI has nothing to do with neuro psychiatric and medical diseases at that time. If the memory loss is persistent, stubborn, usually with disturbance of consciousness, deep development delay, brain cell damage, as well as encephalitis, schizophrenia, amnesia and other physiological and mental diseases.

（1） Symptom description

The main manifestations of memory decline are: it is difficult to quickly and clearly identify and leave a deep mark in the brain; it is difficult to recognize and recall the recorded content smoothly and accurately, or can not take the initiative to present it in the mind again; the memorized content cannot be effectively maintained or maintained, and the capacity is significantly reduced, However, it is difficult to keep the memorized contents firmly in the brain, or a considerable number of the memorized contents retained in the brain are in a vague state.

Memory decline has obvious stage, that is to say, it appears in a certain period of time, with obvious self feeling, as if memory solidified. For example, when reading a book, you can neither read nor remember the contents of the book. If you try to recall the contents of the book, your mind will be blurred. Although memory loss is also diffuse, sometimes it is difficult to remember anything in the stage of memory loss, but memory impairment is mainly manifested in activities that are of great significance to themselves or are too concerned, too sensitive and too worried. For example, for those who take part in the work, it is mainly the work arrangement and quality requirements, so the memory loss is still quite situational. The performance of memory decline in other activities is only the delay of the memory decline which still has obvious situation.

（2） Pathogenesis

A considerable number of elderly people may have memory impairment without dementia as they grow older. At present, memory impairment has formed a general diagnostic standard, with corresponding neuroimaging and neuropathological changes. The most important finding is that there is evidence to prove that memory impairment may be the clinical manifestation of pre Alzheimer's disease. Therefore, the study of memory impairment has become a new field of Alzheimer's disease research in recent years.

The neuropathological changes of Alzheimer's disease include senile plaques in cerebral cortex, hippocampus and other parts, neuronal fiber tangle and neuron loss, but these changes can also be seen in normal aged brain. Recent studies have shown that the loss of neurons in hippocampus and parahippocampal region is different between normal elderly and Alzheimer's disease patients. In the non dementia elderly brain, neuron loss occurred in the lower foot, while other parts of the hippocampus were rarely involved, and the entorhinal cortex was not involved; in patients with Alzheimer's disease, severe neuron loss was found in the CA1 area of the hippocampus and layers II and IV of the entorhinal cortex. Even in patients with mild Alzheimer's disease, 50% of the neurons in layers II and IV could be lost. Layer II and layer IV neurons are very sensitive to degenerative injury. Layer II is the first time to appear neuronal fiber tangle and have nerve cell loss. In patients with severe dementia, the total number of nerve cells in layer II can be reduced by 90% and layer IV by 70%. However, the area is not affected in the elderly without dementia. In the patients with memory impairment, the number of neurons in the entorhinal cortex was 32% less than that in the control group, and the loss of neurons in layer II was up to 60%. Meynert nucleus is an important cholinergic neuron nucleus, which is often damaged in Alzheimer's disease patients. Recent studies have shown that the number of neurons in the Meynert nucleus of patients with memory impairment can also be reduced, so the neuropathological changes of patients with memory impairment are between normal aging and senile dementia.

（3） Preventive measures

Memory decline is one of the specific manifestations of brain aging. Memory loss as a symptom, in addition to some genetic factors, it should be said that the day after tomorrow can be well prevented. To prevent memory decline, we must prevent brain aging. There are great individual differences in brain aging, which are closely related to genetic factors, living environment, education level and economic status. The purpose of brain health care is to slow down brain aging, strive for healthy aging or maintain active aging. Although brain aging is an unchangeable objective law, we can still delay its progress as much as possible.

1. Stay happy

Emotion is closely related to the physiological and biochemical changes of the body. Bad emotions, such as depression, anxiety and depression, anger and fear, make the nervous system function imbalance, destroy the balance of various neurotransmitters, thus accelerating the aging process of neurons. Pleasant emotions play a positive role in maintaining and promoting mental health and preventing brain aging.

2. Keep learning and sports

The human brain has great potential function, so it is advocated to use more brain and more memory. Otherwise, the brain will be in a state of inhibition, and the brain cells will lack of stimulation, resulting in the gradual aging and decay of nerve cells. Physical activity can exercise the whole body and nervous system, so as to increase the cerebral blood flow and enhance the activity ability of the brain.

3. Good living environment

Including reasonable nutrition, living conditions, family relations and so on.

4. Avoid the damage of harmful factors

Alcohol, tobacco, some metal ions, such as aluminum, manganese, zinc, etc.

5. Rational drug use

People become ill after middle age