Retrospective Memory - Retrograde Amnesia

Retrograde Amnesia

Retrograde amnesia is defined as the loss of memory of events and experiences occurring prior to an illness, accident, injury, or traumatic experience such as rape or assault. The amnesia may cover events over a longer or only a brief period. Typically, it declines with time, with earlier memories returning first. There are many possible causes of amnesia. The most common include Alzheimer’s disease, traumatic brain injury, brain infection (such as encephalitis or meningitis), dementia, seizures, and stroke. Less common causes include a brain tumor or psychiatric disorders (schizophrenia, depression, criminal behavior, or psychogenic amnesia). Psychogenic amnesia usually happens in close association with a stressful event that involves serious threat to life or health. There are two types of retrograde amnesia, one dealing with episodic memory, and one dealing with semantic memeory. Semantic retrograde amnesia involves loss of generic, lifelong knowledge, as in the various forms of aphasia or agnosia, and also loss of learned motor skills, as in the various types of apraxia. Its primary focus is on retrograde amnesia for specific, usually time-limited, knowledge. In the case of semantic retrograde amnesia, memory for public events and memory for people have formed the primary corpus of research.