Parallel amnesia is a type of amnesia in which the patient is mainly unable to remember what happened after the amnesic event occurred. The patient’s memory prior to the amnesia can be preserved, recall of new events and happenings is severely impaired, and taste and touch sensations may be affected. Retrograde amnesia refers to the inability to recall a certain period of events prior to the onset of the disorder, where information about past memories is partially lost. Retrograde amnesia may be related to side effects from the regular use of sedative-hypnotic drugs. Parallel and retrograde amnesia are two forms of amnesia that may be related to trauma, concussion, cerebral contusion, cerebrovascular disease and should be treated for the cause. For retrograde amnesia caused by side effects of medication, adjust the dose of the medication and ideally discontinue it.