How is a concussion diagnosed? In fact, the diagnosis of a concussion is primarily based on clinical manifestations such as a clear history of head trauma, temporary confusion, and retrograde amnesia. Concussions can also undergo some routine examinations, such as CT scans of the head, X-rays of the head, electroencephalography, cerebral blood flow imaging, and cerebrospinal fluid analysis. However, these test results are usually negative, meaning that the diagnosis of a concussion mainly relies on clinical manifestations and there are no effective diagnostic tests.