Editing Retrograde amnesia (section)

=== Traumatic brain injury (TBI) ===
Traumatic brain injury (TBI) occurs from an external force that causes structural damage to the brain, such as a sharp blow to the head, a [[diffuse axonal injury]],<ref name="Wolf_2001">{{cite journal | vauthors = Wolf JA, Stys PK, Lusardi T, Meaney D, Smith DH | title = Traumatic axonal injury induces calcium influx modulated by tetrodotoxin-sensitive sodium channels | journal = The Journal of Neuroscience| volume = 21 | issue = 6 | pages = 1923–30 | date = March 2001 | pmid = 11245677 | pmc = 6762603 | doi = 10.1523/JNEUROSCI.21-06-01923.2001 }}</ref> or childhood brain damage (e.g., [[shaken baby syndrome]]).<ref name="Wolf_2001"/> In cases of sudden rapid acceleration, the brain continues moving around in the skull, harming brain tissue as it hits internal protrusions.<ref name="Hardman_2002">{{cite journal | vauthors = Hardman JM, Manoukian A | title = Pathology of head trauma | journal = Neuroimaging Clinics of North America | volume = 12 | issue = 2 | pages = 175–87, vii | date = May 2002 | pmid = 12391630 | doi = 10.1016/s1052-5149(02)00009-6 }}</ref>

TBI varies according to impact of external forces, location of structural damage, and severity of damage ranging from mild to severe.<ref name="Winocur_2001">{{cite journal | vauthors = Winocur G, McDonald RM, Moscovitch M | title = Anterograde and retrograde amnesia in rats with large hippocampal lesions | journal = Hippocampus | volume = 11 | issue = 1 | pages = 18–26 | date = 2001 | pmid = 11261769 | doi = 10.1002/1098-1063(2001)11:1<18::AID-HIPO1016>3.0.CO;2-5 | s2cid = 4079756 }}</ref><ref name="Wolf_2001"/><ref name="Hardman_2002"/> Retrograde amnesia can be one of the many consequences of brain injury but 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.<ref name="YarnellLynch">{{cite journal | vauthors = Yarnell PR, Lynch S | title = Retrograde memory immediately after concussion | journal = Lancet | volume = 1 | issue = 7652 | pages = 863–864 | date = April 1970 | pmid = 4191508 | doi = 10.1016/S0140-6736(70)91691-0 }}</ref>

Specific cases, such as that of patient ML, support the evidence that severe blows to the head can cause the onset of RA.<ref name="Levin_1998">{{cite journal | vauthors = Levine B, Black SE, Cabeza R, Sinden M, Mcintosh AR, Toth JP, Tulving E, Stuss DT | display-authors = 6 | title = Episodic memory and the self in a case of isolated retrograde amnesia | journal = Brain | volume = 121 | issue = Pt 10 | pages = 1951–1973 | date = October 1998 | pmid = 9798749 | doi = 10.1093/brain/121.10.1951 | doi-access = free }}</ref> In this specific case there was an onset of isolated RA following a severe head injury. The brain damage did not affect the person's 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.<ref name="YarnellLynch"/>