Retrograde amnesia can be one of the many consequences of brain injury but it is important to note that it is not always the outcome of TBI. An example of a subgroup of people who are often exposed to TBI are individuals who are involved in high-contact sports. Research on football players takes a closer look at some of the implications to their high-contact activities. Enduring consistent head injuries can have an effect on the neural consolidation of memory.Specific cases, such as that of patient ML, support the evidence that severe blows to the head can cause the onset of RA. In this specific case there was an onset of isolated RA following a severe head injury. The brain damage did not affect the persons ability to form new memories. Therefore, the idea that specific sections of retrograde memory are independent of anterograde is supported. Normally, there is a very gradual recovery, however, a dense period of amnesia immediately preceding the trauma usually persists. Traumatic events
RA can occur without any anatomical damage to the brain, lacking an observable neurobiological basis. Primarily referred to as psychogenic amnesia or psychogenic fugue, it often occurs due to a traumatic situation that individuals wish to consciously or unconsciously avoid through intrapsychic conflicts or unconscious repressions.
Reactionary disturbances effect emotional and motivational responses as well, but reflect the failure to cope with environmental demands. Someone with this might withdraw from the environment that they are placed in because they no longer know how to handle the cognitive resources. Nutritional deficiency
RA has been found among alcohol-dependent patients who have Korsakoffs syndrome. Korsakoffs syndrome patients develop retrograde amnesia due to a thiamine deficiency (lack of vitamin B1). Also, chronic alcohol use disorders are associated with a decrease in the volume of the left and right hippocampus.These patients regular diet consists mostly of hard alcohol intake, which lacks the necessary nutrients for typical development and maintenance. Therefore, after a prolonged time consuming primarily alcohol, these people undergo memory difficulties and ultimately develop RA. However, some of the drawbacks of using Korsakoff patients to study RA is the progressive nature of the illness and the unknown time of onset. Infections
Infections that pass the blood–brain barrier can cause brain damage (encephalitis), sometimes resulting in the onset of RA. In the case of patient SS, the infection led to focal or isolated retrograde amnesia where there was an absence of or limited AA. Brain scans show abnormalities in the bilateral medial temporal lobes, including two thirds of the hippocampal formation and the posterior part of the amygdala. Surgery
Henry Molaison had epilepsy that progressed and worsened by his late twenties. The severity of his condition caused him to undergo surgery in an effort to prevent his seizures.