Memory loss which is also referred to as Amnesia is an abnormal degree of forgetfulness and/or inability to recall past events.
Memory loss, depending on the cause, may have either a sudden or gradual onset, and it may be permanent or temporary. Memory loss may be limited to the inability to recall recent events, events from the distant past, or a combination of both. Transient global Amnesia is a rare, temporary, complete loss of all memory. Anterograde Amnesia refers to the inability to remember recent events in the aftermath of a trauma, but recollection of events in the distant past in unaltered. Retrograde Amnesia is the inability to remember events preceding a trauma, but recall of events afterwards is possible. Memory loss has multiple causes including a number of chronic medical and psychological conditions , trauma, medications, drug or alcohol abuse , and infections.