1, memory impairment The memory impairment of Alzheimer’s disease is characterized by impaired ability to remember new knowledge and difficulty in recalling distant knowledge. Memory impairment is the first symptom of Alzheimer’s disease. There is both amnesia – the defect of remembering new knowledge, which is related to the function of the cerebral cortex; and amnesia – the defect of far-memory (the ability to recall the information that has been remembered in the past), which is related to the dysfunction of the subcortex. That is, firstly, the near memory is impaired, and then the far memory is also impaired, and eventually both the near and far memory are impaired, so that the daily life is affected. The patient may also have fictitious phenomenon, which is related to his learning and memory impairment, and related to the patient’s inability to monitor his own answers or correct his own mistakes. 2, visuospatial skill disorder In the early stage of Alzheimer’s disease, there is visuospatial skill damage. The patient cannot accurately judge the position of an object; when reaching for an object, the patient may not reach the object and grab it, or the patient may reach too far and knock the object down. Inability to correctly determine where to place objects, for example, not being able to accurately place a pot or kettle on the eye of the stove, causing the pot or kettle to fall to the ground as a result of misplacing it. Getting lost in familiar surroundings can also be seen in the early stages. In the middle stage, disorientation occurs even in one’s own home, when one cannot find one’s own room and does not know which bed is one’s own. In simple drawing tests, the patient cannot copy three-dimensional drawings accurately, and even simple flat drawings are difficult to draw after the middle stage. In daily life, there are obvious difficulties in dressing, picking up the clothes can not judge its up and down and left and right, such as the chicken heart collar put on the opposite way, pants put on the opposite way, or even the trouser leg as the sleeve of the blouse. Language disorder Language disorder is a sensitive indicator of higher brain dysfunction. In spontaneous speech, obvious difficulty in finding words is the first manifestation of language disorder. Due to the lack of substantive words in the spoken language and become unable to express the meaning of the empty words; or in the difficulty of finding words, with too many explanations to express the words that can not be said to become redundant. Although there is difficulty in finding words in the early stage, but the naming of items may be normal, listing impaired is a sensitive indicator of the early stage of dementia. With the development of the disease, spontaneous speech becomes more and more empty, and naming is more and more obvious. First, the ability to name less frequently used nouns is impaired, followed by an inability to name commonly used objects and relatives, and mispronunciation accompanies the inability to name. Pronunciation, intonation, and grammatical structure of speech are relatively preserved in Alzheimer’s patients until late in life, while semantic aspects are progressively impaired. As the dementia progresses, the pragmatic content of the language decreases and inappropriate extraneous vocabulary is added and themes are changed. Family members often refer to this as “rambling”, so that despite the chatter, the listener is unable to understand his or her coherent thinking from the conversation, or even to express any information, which is a characteristic of the spontaneous speech of patients with dementia. At the same time, listening comprehension is severely impaired, answers are often irrelevant, the ability to converse decreases to the point of not being able to converse, and then mimicry of speech and redundancy occur, and finally the patient is only able to produce unintelligible sounds, eventually becoming mute. For most of the course of the disease, the mechanical parts of speech production remain normal, and articulation is not impaired, as are the other primary movements. Stuttering and/or slurred grunts occur only in the later stages of the disease. Dysgraphia often occurs in the early stages of Alzheimer’s disease. Dysgraphia may be the first symptom that attracts the attention of family members (e.g., writing a letter) because of the lack of meaning in what is written. Studies have linked writing errors or dysgraphia to distant memory deficits. As the disease progresses, a large number of misspellings occur (strokes that look like Chinese characters, but with incorrect strokes, or even new characters that do not exist). To the middle and late stages of the disease, patients even do not recognize their own names and cannot write their own names. 5. Loss of use and recognition It is very difficult to examine the loss of use and recognition in patients with Alzheimer’s disease, and it is difficult to distinguish their loss of use and recognition from the incompetence due to aphasia, visuospatial skill disorders and amnesia. About 1/3 of patients have visual agnosia. Those with face perception inability do not recognize the faces of loved ones and familiar friends. Impaired self-recognition can produce the mirror sign, in which the patient sits in front of a mirror and talks to his or her own image in the mirror, or even asks his or her own image, “Who are you? Alzheimer’s patients may show two types of dysfunctions: Conceptual dysfunctions are the inability to correctly perform consecutive complex movements with gestures, such as filling a pipe, striking a match, or lighting a cigarette. Ideomotor deactivation is the inability to make spontaneous movements on command, e.g., the patient will use a toothbrush to brush his or her teeth early in the morning, but cannot do so on command. Dysfunctions are common in the middle stage, after memory and language deficits have become apparent and before motor failures become apparent. Patients show that they have lost the skills they have mastered, for example, they can ride a bicycle or swim, but not after the disease, and in severe cases, they can’t use any tools, and even can’t hold chopsticks or eat with a spoon. 6, dyscalculia dyscalculia often appears in the middle stage of dementia, but may be manifested in the early stage, such as shopping can not count or miscalculation of the bill. Calculation disorder may be due to visuospatial impairment (inability to make correct equations); or due to aphasia, inability to understand the requirements of arithmetic assignments; or it may be a primary inability to calculate. Severe cases even simple addition, subtraction can not calculate, and even do not recognize the numbers and arithmetic symbols, and can not answer the inspector is stretching out a few fingers. 7, poor judgment, distraction Alzheimer’s patients can be poor judgment, generalization ability loss, distraction, loss of recognition and lack of concentration in the early stage. In the early stages of dementia, despite the obvious memory impairment, empty language, generalization and calculation ability is impaired, but patients still continue to work is not rare. This is either due to the fact that the work is very skillful and is simply repeated every day, but the inability to work is only recognized when a new situation arises or a new request is made to the patient, or the patient has memory loss and continues to work despite errors in his work because he is understood by his colleagues around him. With memory loss, patients with vascular dementia will gradually develop inattentiveness and varying degrees of loss of calculation, orientation, and comprehension. The difference with Alzheimer’s disease is that Alzheimer’s disease patients may have a total loss of intelligence until complete loss, while vascular dementia patients have a “patchy” loss of intelligence, and it has been observed that the most common is the reduction of temporal orientation, calculating power, near-memory, spontaneous writing and transcription, and the decline of intelligence is not comprehensive. Brain damage due to vascular lesions, on the other hand, may present a variety of associated neuropsychiatric symptoms depending on the location: in general, lesions located in the cortex of the left cerebral hemisphere may present with aphasia, dysarthria, dyslexia, dysgraphia, dyscalculia, etc.; cortical lesions located in the right cerebral hemisphere may present with visuospatial dysfunctions; lesions located in the subcortical nuclei and their conduction tracts may present with corresponding motor, sensory and Extrapyramidal disorders, may also appear strong smile, strong crying symptoms, sometimes may also appear hallucinations, self-talk, rigidity, muteness, indifference and other mental symptoms. 8, mental functional psychiatric disorders In the early stages of Alzheimer’s disease, personality and social behavior may still be apparently intact, despite the insidious intellectual decline. Because these behaviors are preserved, the patient is still able to socialize effectively, often causing others to underestimate or excuse the patient’s incompetence. Emotional apathy often appears early, and the patient often has a facial stupidity of sorts. In fact, psycho-functional psychiatric symptoms are also seen early, with patients exhibiting mania, hallucinatory delusions, depression, personality changes, and delirium. In the past, more attention has been paid to cognitive dysfunction in patients with Alzheimer’s disease and psychotic symptoms have been ignored; in fact, psychotic disorders may be more prominent. The presence or absence of psychotic symptoms and which psychotic symptoms are present may reflect different subtypes of dementia and may indirectly reflect genetic differences in dementia. These conditions suggest that elderly people with predominantly functional psychiatric disorders and a short duration of illness should be considered for the possibility of senile dementia, to avoid mistakenly sending senile dementia patients with depression, mania, and behavioral disorders (aggression, running amok) to psychiatric hospitals for treatment. 9, movement disorders in patients with Alzheimer’s disease often show normal movement in the early stage, to the middle of the disease is manifested as excessive activity of restlessness. Such as walking back and forth indoors aimlessly, or getting up in the middle of the night, touching everywhere, opening and closing doors, and moving things. With the loss of instinctive activities, incontinence (urine is not easy to control may appear earlier), life can not take care of themselves. Although patients with Alzheimer’s disease do not develop movement disorders until late in life, increased muscle tone is not uncommon, even in patients with mild and moderate dementia, most of them can show extrapyramidal signs: for example, the appearance of muscle tonus involving the upper and lower limbs and neck, decreased movement, tremor, abnormal flexion posture. When the patient’s mental retardation is not prominent or neglected and extrapyramidal signs are present, it is easy to be confused with Parkinson’s disease in the diagnosis. In the late stage of the disease, symptoms and signs of the pyramidal system and extrapyramidal system gradually appear, or the existing extrapyramidal signs are aggravated, and finally tonic or flexion quadriplegia is presented. There is a generalized decline in intelligence, with no conscious response to external stimuli and immobile muteness. Based on the above disease signals, clinical diagnosis also requires a physical examination, especially an examination of higher neurologic function, often combined with the measurement of dementia scales. Commonly used scales are the Mental State Mental Status Examination (MMSE), the Hasegawa Simple Intelligence Scale (HDS) to determine the degree of mental retardation, and the Hachinski Ischemic Scale to identify the type of dementia. In addition, necessary laboratory tests such as electroencephalogram (EEG), cranial CT and MRI, cerebral blood flow measurement (r-CBTSPECT), and blood biochemical tests are used to further strengthen the clinical diagnosis and differential diagnosis. In order to treat dementia as early as possible, correctly and actively, especially those curable dementia.