Parkinson’s disease is a group of syndromes that occur in the middle-aged and elderly population, with slowly progressive clinical manifestations characterized by extrapyramidal neurological deficits such as resting tremor, increased muscle tone, and motor slowing. In the past, it was always believed that Parkinson’s disease did not cause cognitive dysfunction. However, with medical advances and intensive research into the disease, this notion has begun to change, meaning that Parkinson’s disease does not only affect the motor system, but also non-motor systems such as cognitive function. It is now known that Parkinson’s disease occurs primarily as a result of degeneration, reduction, and loss of nigrostriatal dopamine neurons, which reduces the dopamine transmitters acting on the striatum, resulting in an imbalance of dopamine and acetylcholine balance in the striatum. Studies have also confirmed lighter, paler colors in the dense midbrain substantia nigra and pontine blue spots, and microscopic findings of degeneration, reduction, and loss of pigment neurons, as well as free pigment granules and astrocyte proliferation. A characteristic diagnostic finding is the presence of Lewy bodies, an intracellular inclusion structure with an eosinophilic central part surrounded by a pale lunar halo, in the pigmented neurons. Lewy body inclusion bodies are immunocytochemically stained positive for ubiquitin proteins and αβ lattice microfilament proteins due to abnormal cytoskeletal proteins. This particular ubiquitin protein staining positive filamentous structure is seen not only in the substantia nigra but also in the hippocampal CA2 and 3 regions, the dorsal nucleus of the vagus, the basal nucleus of Meynert and the amygdala. These areas coincide with functional areas of the brain such as learning, judgment, and information storage, which directly affect the patient’s cognitive, psychosomatic, and emotional abilities. Therefore, clinicians are now beginning to pay attention to a number of non-motor symptoms in patients with Parkinson’s disease in addition to the abnormal motor system symptoms mentioned above. 1. In terms of mental symptoms, inattention is a fairly common symptom in patients with Parkinson’s disease. It may be accompanied by reduced movement, slow speech, and depressed mood. Some patients have inattentiveness, physiological illusions and even visual-spatial perception impairment. Hallucinations, delusions of victimization and hypochondriac delusions, and association disorders are relatively rare. 2. In terms of mood, a few patients have reduced active activities, personality changes, euphoria, childish behavior, isolation, timidity, depression, hesitation, suspicion, irritability, self-centeredness, etc. They are reluctant to participate in social activities and seldom visit friends and relatives. These are the manifestations of multiple psychological disorders such as depression and anxiety, and 2% of patients can develop depression and anxiety disorder. Depressive state is more common in female patients, manifested as slow reaction, depressed mood, anxiety, serious cases may have suicide attempts. The degree of depression is associated with neuropathy, and unresponsiveness, depressed mood, anxiety, and suicide attempts are often the main reasons for psychiatric visits. 3, Parkinson’s disease patients cognitive dysfunction is mainly manifested in inattention and memory impairment. In the early stage, memory, calculation and orientation are still normal, but in the late stage, patients will develop a comprehensive cognitive impairment. The incidence of dementia can reach 26%, 28%, and 48% after 3, 5, and 15 years, respectively, and only 15% of patients have no cognitive impairment. It can be seen that Parkinson’s dementia is not only common, but also increases rapidly with age and disease duration. Epidemiological data show that 30-80% of patients with Parkinson’s disease develop Parkinson’s dementia after 8-10 years, with the incidence of Parkinson’s dementia in the 65-year-old patient population being 0.2% -0. 5%, and patients with Parkinson’s disease are 4-6 times more likely to develop dementia in the next 5 years than the healthy population. The incidence of dementia is even higher if Parkinson’s is caused by other diseases (so-called Parkinson’s syndrome or Parkinson’s superimposed syndrome), such as encephalitis, cerebrovascular disease, CO poisoning, multisystem atrophy, and pharmacological Parkinson’s (e.g., long-term use of drugs such as reserpine). After all, not all patients with Parkinson’s disease will develop dementia, and even if dementia symptoms appear, the time of appearance varies greatly from patient to patient, and the following phenomena can be used as a basis for judgment: ① Patients with early age of onset (especially those with onset before the age of 40) are less likely to develop dementia; ② The longer the course of the disease and the more severe the disease progression, the more likely dementia will occur; ③ Patients who have poor intelligence in the early stage are more likely to (3) Patients with poor intelligence in the early stage are more likely to develop dementia later. On the contrary, patients with good intelligence in the early stage have a lower chance of developing dementia later. Patients with severe motor symptoms, especially tonicity, postural instability and gait disorders, are more likely to develop dementia; ⑤ Patients with sleep behavior disorders (such as involuntary shouting and body movement during sleep) and excessive daytime sleep are more likely to develop dementia. What should I do if a patient with Parkinson’s disease develops dementia symptoms? Before treatment, the patient and family must have some necessary psychological preparation. Once dementia develops, the most common psychological changes that patients are likely to experience are low self-esteem and resistance. Therefore, the key to adjustment is to acknowledge and accept the fact and inform the doctor in time, cooperate with the doctor’s observation, and family members and the society to give more care and attention to the patient and to eliminate all kinds of discrimination and isolation measures. Love and care are always the best medicine for patients with all types of dementia. In addition, the daily diet of Parkinson’s disease dementia patients is also a great learning. Studies have found that calcium intake through food can promote the synthesis of dopamine in the brain, so you should usually eat more calcium-rich foods, such as: shrimp, kelp, nori, soy milk, soy products, milk, eggs, etc., which have a good effect on the prevention of Parkinson’s disease dementia. In conclusion, pleasant meals and a varied combination of meals have a good effect on the prevention of Parkinson’s disease. Therefore, a day’s diet should include a variety of foods, including cereals, vegetables, fruits, beans, meat, etc. It has been determined that eating 300-500g of cereal per day can provide sufficient carbohydrates, protein, dietary fiber and vitamin B and other nutrients; eating about 400g of vegetables and one to two medium-sized fruits per day, from which you can obtain vitamins A, B, C, E and a variety of minerals and dietary fiber. Foreign studies have proven that consuming more vitamin-rich antioxidant foods can reduce the risk of Parkinson’s disease. For example, people who drink 1 to 2 cups of coffee a day can reduce the incidence of Parkinson’s disease by 50%; if they drink 3 to 4 cups of coffee a day, the chance of getting Parkinson’s disease is only 1/5 of a normal person’s. The caffeine contained in caffeinated beverages can increase the sensitivity of neurotransmitters in the brain, which can effectively reduce Parkinson’s disease s muscle stiffness symptoms. Currently, the treatment of Parkinson’s dementia is mainly based on drugs. Among the drug treatments for Parkinson’s dementia, the safety and efficacy of cabalatine for treatment are the most well documented clinically, It is well tolerated. Drugs such as donepezil, galantamine and memantine for Alzheimer’s dementia can also be used in the treatment of Parkinson’s dementia, but the therapeutic basis is not sufficient. For patients with Parkinson’s dementia who may also have psychiatric symptoms and mood disorders, clozapine may also be used to improve psychiatric symptoms in patients with Parkinson’s dementia; or selective 5-hydroxytryptamine reuptake inhibitor drugs such as fluoxetine, paroxetine, and sertraline may be used to treat patients with Parkinson’s dementia when they become depressed. For patients with Parkinson’s dementia, care of their lives is especially important because of the impairment of physical movement and the deterioration of intelligence. There should be a person in charge of living and eating. It is important to have someone to take care of the patient’s life and be emotionally caring. It is also important to prevent unexpected situations such as falls, asphyxiation due to accidental inhalation, and suicide due to emotional depression. Only in this way can the patient have a warm and harmonious living and rehabilitation environment to successfully cooperate with the completion of treatment. In conclusion, modern research has found that dementia is already a common symptom in patients with Parkinson’s disease, and its incidence is 4-6 times higher than that of healthy people. For such patients, the dual symptoms of Parkinson’s and dementia can cause serious impact on daily life and can be a huge burden to society. Therefore, the treatment of Parkinson’s disease patients should not only improve motor function and quality of life, but also pay attention to non-motor symptoms, such as mental-emotional and cognitive impairment, because early detection, early medical consultation and early treatment are essential.