1.Memory impairment
Memory impairment in Alzheimer’s disease is characterized by impaired ability to remember new knowledge and difficulty recalling distant knowledge. Memory impairment appears early and is almost the first intellectual impairment detected by the patient’s family or colleagues, especially near-memory impairment – amnesia – and it is even considered doubtful to diagnose Alzheimer’s disease when near-memory impairment is not one of the first symptoms to appear.
Neuropsychological studies of memory deficits have shown that these patients have difficulty in inputting auditory information, information disappears quickly from short-term memory, and storage of information and distant memory are impaired, suggesting that it is not helpful to the patient.
Memory impairment is the initial symptom of Alzheimer’s disease, both amnesia – a deficit in remembering new knowledge, related to cortical function; and amnesia – a deficit in distant memory (the ability to recall information already remembered in the past), related to subcortical dysfunction.
That is, first the near memory is impaired, followed by the distant memory, and eventually both the near and far memory are impaired, making daily life affected. The patient may also have fictitious phenomena, which are related to his learning memory impairment and to his inability to monitor his own responses or to correct his errors.
The patient’s daily performance is characterized by “losing everything”, “forgetting everything”, and asking the same question repeatedly. For example, during a clinical examination, the patient could not remember the doctor’s last name and even denied having told him.
However, the patient’s near-memory impairment is also often neglected as a common forgetfulness in healthy elderly people, especially when early forgetfulness has become obvious, while the distant memory is relatively preserved, so that relatives often believe that the patient’s memory is not poor or even good. The reason is that the patient remembers clearly what happened more than a decade or even decades ago, although there is no denying that “current events are forgotten when you look back”. The above-mentioned situation deserves the attention of the relatives.
Similarly, memory loss is a core symptom of early cerebrovascular dementia, with near memory deficits appearing earliest and distant memory deficits appearing later.
2. Visuospatial skill impairment
In the early stage of Alzheimer’s disease, there is impairment of visuospatial skills. Inability to accurately determine the location of objects; reaching for objects or grabbing them before reaching them, or reaching too far and knocking them over. Inability to judge the position of objects when placing them, such as not being able to place a pot or kettle accurately on the fire eye of the stove, causing the pot or kettle to fall to the ground because of misplacement.
Getting lost in a familiar environment can also be seen in the early stage. In the middle stage, disorientation occurs even in one’s own home, when one cannot find one’s room and does not know which bed is one’s own. In simple drawing tests, patients cannot accurately copy three-dimensional drawings, and after the middle stage, they have difficulty even drawing simple flat drawings. In daily life, there are obvious difficulties in dressing, picking up clothes and not being able to judge their up and down, left and right, such as wearing the chicken collar backwards, wearing the pants backwards, or even using the trouser legs as the sleeves of the top.
3.Language disorder
Language disorder is a sensitive indicator of higher brain function disorder. In spontaneous speech, obvious difficulty in finding words is the first language disorder to manifest. 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, the use of too much explanation to express the words that can not be said and become redundant. In early stages, although there is difficulty in finding words, naming of items may be normal, and impaired listing is a sensitive indicator of early Alzheimer’s disease.
As the disease progresses, spontaneous speech becomes more and more hollow, and the inability to name becomes more and more obvious. First, naming of sparingly used nouns is impaired, followed by inability to name commonly used objects and relatives, and mispronunciation along with the inability to name.
The articulation, intonation, and grammatical structure of speech are relatively preserved in Alzheimer’s patients until late in life, while the semantic aspects are progressively impaired. As dementia progresses, the pragmatic content of speech decreases, and irrelevant words and changing themes are inappropriately added. Family members often refer to this as “talking incoherently”, so that the listener cannot understand the coherent thinking or even express any information from the conversation, which is characteristic of spontaneous speech in Alzheimer’s patients.
At the same time, listening comprehension is severely impaired, often with non-answers, and the ability to converse decreases to the point of being unable to converse, leading to imitative language and reverberant speech, and finally the patient is only able to make unintelligible sounds, ending in silence. During most of the course of the disease, the mechanical parts of speech production remain normal and articulation is not impaired as are other primary movements. Stuttering and/or slurred grunts occur only in the later stages of the disease as it progresses.
4. Difficulty in writing
Difficulty in writing often appears early in the course of Alzheimer’s disease. Difficulty in writing results in poorly written words, which may be the first symptom to come to the attention of the family (e.g., writing a letter). Research suggests that writing errors or loss of writing are associated with distant memory impairment. A large number of misspellings (strokes resembling Chinese characters, but with wrong strokes, or even new characters that do not exist) occur as the disease progresses. By the middle and late stages of the disease, patients do not even recognize their names and cannot write their names.
5. Loss of use and recognition
It is difficult to distinguish loss of use and recognition in Alzheimer’s patients from incompetence due to aphasia, visuospatial skill impairment and amnesia. About 1/3 of patients have visual aphasia. Those with facial cognitive inability do not recognize the faces of loved ones and familiar friends. Impaired self-perception can result in mirror signs, where patients sit in front of a mirror and talk to their own image in the mirror, or even ask their image “who are you?
Patients with Alzheimer’s disease can exhibit two types of disuse: conceptual disuse is the inability to correctly perform continuous complex movements with gestures, such as loading a pipe, striking a match, or lighting a cigarette. Intentional motor disuse is the inability to perform spontaneous movements on command, such as brushing the teeth with a toothbrush every morning, but not on command.
Disuse commonly occurs in the middle stage, after memory and language deficits are apparent and before motor deficits are apparent. Patients show the loss of skills that they have mastered, such as riding a bicycle or swimming, but not after the disease, and in severe cases, they cannot use any tools, or even hold chopsticks or eat with a spoon.
6.Calculation disorder
Dyscalculia often appears in the middle stage of Alzheimer’s disease, but it may show up in the early stage, such as not being able to do shopping or miscalculation. Dyscalculia may be due to visual-spatial impairment (inability to correctly list equations); or due to aphasia, inability to understand arithmetic homework requirements; or may be a primary inability to calculate. In severe cases, even simple addition and subtraction cannot be calculated, and they do not even recognize numbers and arithmetic symbols, nor can they answer how many fingers the examiner is extending.
7. Poor judgment and distraction
Patients with Alzheimer’s disease may have poor judgment, loss of generalization ability, distraction, loss of recognition and lack of concentration at an early stage. In the early stages of dementia, it is not uncommon for patients to continue to work despite significant memory impairment, hollow speech, and impaired generalization and calculation skills. This is either due to very skilled work that is simply repeated daily, but the incompetence is only noticed when new situations occur or new demands are made on them; or their memory is diminished and they continue to work despite errors because they are understood by their surrounding colleagues.
Patients with vascular dementia, along with memory loss, gradually also suffer from inattention and varying degrees of diminished calculation, orientation, and comprehension. In contrast to Alzheimer’s disease, patients with Alzheimer’s disease may experience a general or complete loss of intelligence, whereas in patients with vascular dementia, the decline in intelligence is “patchy” and has been observed to be most common in the form of reduced temporal orientation, calculation, near memory, spontaneous writing and transcription, and the decline in intelligence is not general.
Depending on the location, various neuropsychiatric symptoms may be associated with brain damage caused by vascular lesions: in general, lesions located in the cortex of the left cerebral hemisphere may have symptoms such as aphasia, dyslexia, dyscalculia, dyscalculia, etc.; lesions located in the cortex of the right cerebral hemisphere may have visual-spatial perception impairment; lesions located in the subcortical nuclei and their conduction tracts may have corresponding motor, sensory, and The lesions located in the subcortical nuclei and their conduction tracts may show corresponding motor, sensory and extrapyramidal disorders, and may also show symptoms of strong laughing and crying, and sometimes mental symptoms such as hallucinations, self-talk, rigidity, reticence and apathy.
8.Mental functional psychiatric disorder
In the early stages of Alzheimer’s disease, personality and social behaviors may still be apparently intact, despite the occult intellectual decline. Due to the retention of these behaviors, patients are still able to socialize effectively, often causing others to underestimate or excuse the patient’s incompetence. Emotional indifference is often present early, and patients often have an image of facial silliness.
In fact, psycho-functional psychotic symptoms are also seen early on, with patients exhibiting mania, hallucinatory delusions, depression, personality changes, and delirium. In the past, more attention was paid to cognitive dysfunction in patients with Alzheimer’s disease, while psychotic symptoms were ignored; in fact, psychotic disorders may be more prominent. The presence or absence of psychotic symptoms and what psychiatric symptoms are present may reflect different subtypes of Alzheimer’s disease and may indirectly reflect genetic differences in Alzheimer’s disease.
These conditions suggest that elderly people with predominantly psycho-functional psychiatric disorders and a short duration of the disease should be considered as possible Alzheimer’s disease, and avoid mistakenly sending Alzheimer’s patients with depression, mania, and behavioral disorders (aggression, running around) as manifestations to a psychiatric hospital for treatment.
9.Motor disorders
The movement of Alzheimer’s patients is often normal in the early stage, but in the middle stage, they show the restlessness of over-activity. For example, walking back and forth indoors without purpose, or getting up in the middle of the night, touching everywhere, opening and closing doors, carrying things, etc. This is followed by loss of instinctive activities, incontinence (urination is not easily controlled and may occur earlier), and inability to care for oneself.
Although patients with Alzheimer’s disease do not develop motor deficits until late in life, increased muscle tone is not uncommon, and even in patients with mild and moderate dementia, most can show extrapyramidal signs: such as the presence of muscle tonus involving the upper and lower extremities and the neck, decreased movement, tremor, and abnormal flexion posture. When dementia is not prominent or ignored and extrapyramidal signs are present, it is easy to confuse the diagnosis with Parkinson’s disease.
In the late stage of the disease, symptoms and signs of the pyramidal system and extrapyramidal system gradually appear, or the existing extrapyramidal system signs are aggravated, and finally tonic or flexion tetraplegia appears. There is a general decline in intelligence, no conscious response to external stimuli, and immobility and silence.
Based on the above disease signs, the clinical diagnosis also requires a physical examination, especially a high-level neurological examination, often combined with a dementia scale. Commonly used scales include the Mental State Simple Quick Examination (MMSE) and the Hasegawa Simple Intelligence Scale (HDS) to determine the degree of mental retardation, and the Hachinski Ischemia Scale to identify the type of dementia. In addition, necessary laboratory tests such as EEG, cranial CT and MRI, cerebral blood flow measurement (r-CBTSPECT) and blood biochemical tests were used to further strengthen the clinical diagnosis and differential diagnosis. In order to treat dementia, especially those with treatable dementia, early, correctly and aggressively.