Amnesia (infringement of memory)

The amnesia - infringement of the memory, shown inability to reproduce earlier the acquired knowledge, the gone through events or to remember the new information.

The passing amnesia can be consequence as diseases, and a craniocereberal trauma. It can extend on events, as preceded a trauma or disease, (a retrograde amnesia), and happened after (an anterograde amnesia).

After a heavy craniocereberal trauma the retrograde amnesia sometimes covers hours and even weeks; memory on more remote events usually does not suffer. In process of recover the period retrograde amnesia is reduced, sometimes down to full restoration of memory. More often, however, patients and cannot recollect event of several last minutes before a trauma. It speaks about infringement of short-term memory, cause of the given events do not send to long-term memory. There are messages on disappearance retrograde amnesia later months or years after a trauma; sometimes restoration is promoted, for example, by hypnosis or narcotherapy. Probably, it is caused by restoration before the broken neural circuits responsible for memory.

Duration of an anterograde amnesia, as a rule, corresponds to duration of posttraumatic infringements of consciousness, however sometimes the anterograde amnesia extends even for that period when short-term memory was already restored also by the patient can to repeat numerical numbers correctly, for example. Duration of anterograde amnesia - a parameter of weight of a craniocereberal trauma. In last turn ability to acquire a new material is restored.

The passing full amnesia is characterized sudden full by an bone-holding amnesia (inability to acquire the new information). Usually it arises at persons older 50 years, is frequent after emotional or physical activity. During an attack of the patient it is not braked, contacted, cognitive functions at first sight are not changed, neurologic symptoms are absent. However it constantly asks that has occured a minute ago, and the impression of confusion of consciousness is often made. During an attack orientation is roughly broken, the patient constantly asks: "Who am I? Where am I? What's with me?" The bone-holding amnesia meshs with an retrograde amnesia on events which have occured directly up to an attack. Memory and other mental functions are restored in some hours, however the patient cannot recollect anything, that occured during an attack.

The reason of disease usually does not manage to be found out. Communication of attacks with cerebrovascular diseases, epilepsy (7 % in one of researches), a migraine, infringements of a rhythm of heart is sometimes traced. At inspection of 277 patients with a passing full amnesia in clinic of Mayo it has appeared, that in the anamnesis 14 % have a migraine and for 11 % - cerebrovascular diseases, however attacks of an amnesia did not coincide with attacks of a migraine or an ischemia of a brain. Approximately at a quarter of patients a passing full amnesia anticipate, but the risk of an insult thus is not raised. Rare cases of sudden and proof loss of memory are described. Approximately at 20 % of patients attacks repeat. The reason happens a migraine, temporal epilepsy, a passing ischemia in pool of a back brain artery.