Alzheimer’s disease (AD) is a progressive neurodegenerative disease with insidious onset. It is characterized clinically by a full spectrum of dementia including memory impairment, aphasia, dysfluency, dyscognition, impairment of visuospatial skills, executive function impairment, and personality and behavioral changes. The onset of the disease is slow or insidious, and patients and family members often cannot say when the disease started. It is mostly seen in elderly people over 70 years old (average 73 years old for men and 75 years old for women), and in a few patients, the symptoms rapidly become clear after physical illness, fracture or mental stimulation. There are more women than men (3:1 female:male). The main manifestations are cognitive decline, psychiatric symptoms and behavioral disorders, and gradual decline in daily living ability. Due to the spread of medical knowledge and the widespread or even excessive attention given to Alzheimer’s disease, some diseases similar to Alzheimer’s symptoms have been mistaken for Alzheimer’s disease, including normal pressure hydrocephalus. Normal pressure hydrocephalus (NPH) is a clinical syndrome that occurs in adults with chronic hydrocephalus and enlarged ventricles but normal brain pressure due to multiple causes. Epidemiology: This disease is only seen in the elderly and its incidence increases with age, making it an age-specific disease. Clinically, the disease is relatively rare, but with the aging of the population, the number of patients with the disease has gradually been taken seriously. According to foreign statistics, the prevalence of NPH is 1.1% in Japanese and 2.1% in Swedish elderly people over 60 years of age. The main clinical manifestations of the disease are called the three main signs, including: 1. cognitive dysfunction The initial symptoms are gradually increasing amnesia, slow mental response and speech impairment, slow development or numerical impairment, decreased observational power and emotional indifference, and finally severe mental impairment and dementia. 2.Gait disorder Patients fall frequently, gradually appear step base widening, gait dragging, limb stiffness, slow movement, lower limbs appear spastic gait. When the disease reaches its peak, gait disorders and hypokinesia are so severe that all voluntary activities are restricted. Urinary incontinence usually follows mental and gait disorders and persists as the disease worsens. Incontinence is rare and occurs only in the most severe cases. In addition to the three main signs mentioned above, personality changes, epilepsy, horizontal nystagmus, extrapyramidal symptoms, grasping reflex, primitive reflex and hypopituitarism may occur. Incomplete paraplegia, hyperactive tendon reflexes of the lower extremities and positive pathological reflexes may occur in the late stages. The cognitive dysfunction and gait impairment seen in these patients often leads to a perception of dementia, which is not treated aggressively or is treated incorrectly. In fact, normal pressure hydrocephalus is a condition in which symptoms can be significantly improved by a variety of different cerebrospinal fluid diversion procedures. The vast majority of patients will experience varying degrees of improvement in symptoms and cognitive function after surgery.