The purpose of hallucinations is to replace real signals with simulated sensory signals that drive autonomic action. Patients have a dreamy feeling, as if they were dreaming of a strange sensation, often in conjunction with hallucinations, commonly caused by high fever, epilepsy, temporal tumors, etc. What tests should be performed to diagnose what kind of disease is causing the hallucinations? Common tests Cranial CT, cranial MRI, EEG, cerebrospinal fluid lactate, magnetic resonance angiography. Examination methods 1, EEG, BEAM, Holter (EEG, EEG topography, dynamic EEG monitoring): clear pathological waves, spike waves, sharp waves, spike-slow waves or spike-slow waves are seen. 2, If secondary epilepsy should be further performed cranial CT, cranial MRI, MRA, DSA and other examinations can find the corresponding lesions. 3, Lumbar puncture CSF examination, there may be changes. The difference between hallucinations and delusions is that there is no objective stimulus present in the former. Because their feelings are often realistic and vivid, they can cause anger, sadness, panic, escape and even produce emotional or behavioral reactions to attack others. Attempts to persuade the person experiencing the hallucination not to believe it are sometimes futile. Hallucinations can occasionally be seen in normal people.