Take the patient into confidence by spending sometime inquiring into things you know are of interest to the patient. During a certain point in your conversation, inquire from the patient if he has suffered a sharp blow to his head in the recent past. Keep in mind that it not necessary for a patient to become unconscious as a result of a head blow to become the victim of anterograde amnesia. Blows to the head which do not result in unconsciousness can cause amnesia as well.
Apart from a severe injury to the head, brain tumours, infections like encephalitis, neurodegenerative illness, strokes and Alzheimer's disease can be possible causes of anterograde amnesia. Inquire if the patient was a victim of one of these sources of brain damage before moving on to the next step.
If the patient’s answer to your queries in the first two steps does not lead you anywhere, it would be best to look for drug history in the past. Excessive use of alcohol, barbiturates and benzodiazepines can result in anterograde amnesia. Furthermore, hallucinogens can also become the cause of amnesia.
Check for systematic diseases by performing blood tests on a regular basis. If you suspect that an infection of the nervous system might be causing problems, the patient’s lumbar would need to be punctured in order to get a sample of obtain cerebral spinal for further medical tests.
If nothing seems to work, revert to computed tomography and magnetic resonance scans. Furthermore, an EEG may need to be performed to observe the electrical activity going on in the patient’s brain. To detect a possible reduction in flow of blood to the brain can be detected by means of a cerebral angiography.