The arm is always sleepy manifesting as arm weakness, mainly in the following cases: 1. If a young or middle-aged patient has sleepiness and weakness in one side of the arm, ask the patient if there is muscle atrophy, especially interosseous muscle atrophy at the end of the fingers or arm muscle atrophy, whether there is a contralateral side at the same time, and whether there is a feeling of flesh jumping. If there are the above symptoms, you need to consider that the patient may have motor neuron disease, and you need to do electromyography and lumbar puncture, cranial magnetic resonance examination.2. Ask the patient if there is any shoulder pain or neck discomfort on one side. Some patients with frozen shoulder show weakness in one arm during an attack and have difficulty in lifting it.3. For elderly patients, ask the patient if there is hypertension or diabetes, and you need to do cranial magnetic resonance examination Find out if there is any acute cerebrovascular disease, such as cerebral infarction or cerebral hemorrhage.