Retrograde amnesia miasms

Retrograde amnesia (RA) is a loss of memory-access to events that occurred or information that was learned in the past.

Episodic, autobiographical, and declarative memory is hurt while keeping procedural memory intact without increasing difficulty for learning new information. RA can be temporally graded, or more permanent based on the severity of its cause. It is usually consistent with Ribot's law. The law states that subjects are more likely to lose memories closer to the traumatic incident than more memories that happened further from the incident. The type of information that is forgotten can range from a specific memory, such as a single event, or a more general memory. This would resemble generic amnesia. Anterograde amnesia is a similar condition that deals with the inability to form new memories following the onset of an injury or disease.

Infections[edit]

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.