Traumatic brain injury after a fall, if there is a head CT negative retrograde amnesia as well as impaired consciousness and other manifestations, suggesting that there may be a concussion. 1. Patients with concussion may exhibit transient impairment of consciousness, with the onset of unconsciousness or unconsciousness, a process that can last from a few minutes to more than ten minutes, mostly no more than 30 minutes. The onset of concussion may be accompanied by headache, dizziness, nausea, vomiting, poor concentration and other symptoms, but other neurological examination is not abnormal. 2. Patients with concussion may also show retrograde amnesia, i.e., the patient cannot recall the process of the onset of the disease and recent events, but the patient can recall some events in the more distant period before the onset of the disease. 3. There is no abnormality in CT or MRI of the head in patients with concussion because the symptoms of concussion are similar to those of some other intracranial diseases, so patients need to rule out epidural hemorrhage and subarachnoid hemorrhage and other diseases through CT examination. If a patient falls and suspects concussion, he or she should seek prompt medical attention and be actively diagnosed and treated under the guidance of a doctor to avoid delays in his or her condition.