1. Diagnostic basis (1) Middle-aged and elderly onset, slowly progressive course. (2) At least two of the four main signs (resting tremor, myotonia, bradykinesia, postural gait disorder) are present, and at least one of the first two is present, with asymmetric symptoms. (3) Effective levodopa treatment and positive levodopa test or apomorphine test support the diagnosis of primary PD. (4) The patient does not have extraocular muscle palsy, cerebellar signs, postural hypotension, cone system damage and myasthenia gravis, etc. The compliance rate between clinical diagnosis of PD and autopsy pathological confirmation is 75% to 80%. (1) Diagnosis of primary Parkinson’s disease (IPD): Wang Xinde authored the criteria developed at the National Extrapyramidal Conference in October 1984 as follows: ① At least two of the following four typical symptoms and signs (resting tremor, hypokinesia, rigidity, and impaired position reflexes) must be present. ②The presence of atypical signs and symptoms that do not support the diagnosis of IPD, such as pyramidal fasciculus, disuse gait disturbance, cerebellar symptoms, intention tremor, gaze palsy, severe autonomic dysfunction, and significant dementia with mild extrapyramidal symptoms. (iii) Reduced hypervanillic acid in cerebrospinal fluid is helpful in confirming the diagnosis of early Parkinson’s disease (PD) and idiopathic tremor (ET), drug-related Parkinson’s syndrome with PD. In general, ET is sometimes difficult to differentiate from early IPD, and ET mostly presents with positional and motor tremor of the hands and head without increased muscle tone and hypermobility. (2) Diagnosis of secondary Parkinson’s syndrome (SPDS): ①Medication PS (MPS): Medication PS is clinically difficult to distinguish from IPD, and it is important to rely on whether there is a history of taking antipsychotic drugs, in addition, the symptoms of medication PS are symmetrical on both sides, and sometimes can be accompanied by hyperactivity side will first appear symptoms, if the clinical identification is difficult, the application of antipsychotic drugs can be suspended, if If the PS is pharmacological, the PS symptoms usually disappear in a few weeks to 6 months. (2) Vascular PS (VPS): this sign is characterized by the absence of tremor, often accompanied by focal neurological signs (e.g., pyramidal fasciculus sign, pseudobulbar palsy, emotional instability, etc.), the course of the disease is mostly step-like progression, and treatment with L-dopa agents is generally ineffective. (3) Diagnosis of symptomatic Parkinson’s disease syndrome (heterogeneous systemic degeneration): ①Progressive supranuclear degeneration: sometimes it is difficult to distinguish from Parkinson’s disease. The clinical features of progressive supranuclear palsy are mainly reduced movements, neck tonicity with slight backward tilt and pseudomyelination and upward gaze palsy. Olivopontocerebellar atrophy: primary Parkinson’s disease should be differentiated from this disease. Olivopontocerebellar degeneration can also be clinically characterized by hypermobility, tonicity, or even resting tremor, but there are more cerebellar symptoms such as ataxia, etc. Characteristic changes can also be seen on CT examination, and blood glutamate decarboxylase activity is reduced. Striatal nigrostriatal degeneration: This disease is imagined to be very different from primary Parkinson’s disease, and it is difficult to differentiate clinically, mainly relying on pathological diagnosis. ④Shy-Drager positional hypotension syndrome: clinical manifestations are positional hypotension, urinary and fecal incontinence, absence of sweating, and small muscle atrophy in the distal limbs, etc. Sometimes, it can also be accompanied by Parkinson’s disease syndrome. If the patient is clinically found to have Parkinson’s disease syndrome and mild autonomic disorder symptoms, it needs to be differentiated from primary Parkinson’s disease. Dementia: Dementia with Parkinson’s syndrome is not uncommon. In addition to dementia, advanced Alzheimer’s disease also has extrapyramidal symptoms such as hyperkinesia, tonicity and orofacial hyperactivity, and because Parkinson’s disease can be accompanied by dementia even in the early stages, the two need to be differentiated by follow-up. Normal cranial pressure hydrocephalus: The disease is characterized by gait disturbance, urinary incontinence and dementia, and sometimes symptoms of Parkinson’s disease, such as hypermobility, tonicity, and resting tremor. (vi) Genetic degenerative diseases: A. Pallidobulb-Spatz disease (Hallervorden-Spatz disease). B. Huntinton chorea. C. Lubag (X-linked dystonia-PDS). D. Mitochondrial cytopathy with striatal necrosis. E. Neural acanthocytosis (beta-lipoprotein deficiency). F. Hepatomegaly (Wilson’s disease). Primary PD accounts for 75% to 80% of the total number of these clinical types, secondary (or symptomatic) PD is relatively uncommon, and genetic degenerative disease with Parkinson’s superimposed syndrome accounts for 10% to 15%. IPD is considered in most middle-aged and elderly patients who have significant slowing, reduction in movement, muscle tonus, and tremor, while those with early or atypical symptoms are sometimes misdiagnosed.