Amnesia (gr. amnesia - forgetfulness, loss of memory) - a weakening of (lack of) memory, the unconscious; in a more narrow sense - the gaps of memories.
Each perceptions and experience of the person leaves in the brain trace (engramm). Memory is the ability to impress (voluntary and involuntary memorization) these tracks, handling, i.e. to their protection (retention), reproduction (reproduction) and recognition. In the structure of memory may prevail sensual-shaped or logical-semantic components. Thanks memory you can create the experience and consciousness of the past. Memory disorders (gimnazii) are usually expressed in weakening named abilities (hypomnesia, amnesia). There are congenital weakness of memory found in oligofrenia different degrees, and acquired, which may come in many forms of mental illness. Persistent and diffuse (common) decrease different parties memory is characteristic first of all organic psychosis, while the partial loss of memory are observed usually in connection with paroxysmal disorders of consciousness.
Memory loss is manifested in organic diseases of the brain are usually first in weakening playback need at the moment materials, in the weakness of the so-called selective (selective) reproduction of dates, names, numbers, names, and other individual, differentiated material. Particularly affected by this Dating chronological sequence of events (the so-called chronological disorientation). Disorders of reproduction, resulting in the state asthenia after traumas, infections, etc., or in the initial stage organic diseases are, as a rule, partially or completely reversible. Often in organic diseases of the brain early violated the ability to remember new information (fixation amnesia). This disorder is missing memory in current, recent events when security of its purchased in the past knowledge. Disorders of memory are especially pronounced when the Korsakov (amnestic) syndrome and Korsakov psychosis, under certain intoxication (e.g., carbon oxides), skull injuries, atherosclerotic and other organic psychosis. The inability to keep the memory fresh experience to remember the facts and circumstances just happened leads to amnestic the disorientation in the atmosphere and the surrounding persons in time and sequence of events. At roughly organic processes (senile dementia and other strophic disease) there is a deeper form of defeat memory, particularly progressive amnesia, increasing violations of conservation (retention) materials memory, progressive and far-reaching devastation of its reserves, i.e., the acquired information and knowledge. The destruction and loss of memory resources progress in certain regularities: from more specific to more General, later acquired, less firmly fixed and less automated to ensure that the acquired earlier, stronger enshrined, more organized and automated. The most automated and secured motor traces (motor skills, gait, etc) remain so for the longest time. The regularity of a sequence devastation materials memory was formulated by a French psychologist, RIBO (law of RIBO).
The state of stupefaction of consciousness (coma, a spoor, twilight, dreamlike, delirious and amentinies condition, state pathological affect, pathological intoxication, and so on) is usually accompanied by the complete loss of memories (amnesia) for a certain period of time. When leaving such conditions the patient remembers nothing or vaguely remembers only a few facts and images. Loss (usually full) memories of events that preceded the state of altered consciousness or the development of psychotic syndrome, is called retrograde amnesia; this amnesia may cover different periods of time from a few hours and days to several months. If lost memories of experiences that were at the end of disorders of consciousness or conditions, talk about anterograde amnesia. Sometimes both forms are combined (anterogradnaya amnesia), i.e., the memories fall out as on the previous, and of the subsequent events.
Increased memory (hypermnesia) is apparent worsening of memories, sometimes observed in the state of mania. The weakness in the electoral reproduction, in States clouded consciousness during sleep, especially hypnotic, there may be a special form of hypermnesia, which will not be increased memory in General, and in light of the origin and influx shaped memories sensual bright ideas.
In addition to these quantitative changes of memory (weakening or strengthening it), there are also qualitative change, i.e. the deceptions of memory (paramnesia). They are divided into pseudoriemannian (false memories), confabulation (fictions) and cryptomnesia (distortion memory). In patients with delirium, particularly patients with paranoid delusions (see Delusional syndrome), often a "tendency to recycle the past", which leads to false memories, relevant content Breda ("illusion of memory"). The distinction between pseudoresistance and confabulation to a certain extent conditional. Pseudoriemannian usually plays the everyday events that could occur", or actual events that are just wrong localized in time.
Confabulario are usually richer, testify known creative process. There are confabulario arising from the presence of such expressed amnestic disorder, as violations of remembering, amnestic the disorientation, and filling in the gaps of memory that arise in the result of amnestic disorder (substituting, of mnestic confabulario). Confabulario are especially pronounced and abundant in Korsakov syndrome, when loss of memory on current events often combined with multiple, as a rule, ordinary confabulation. Fantastic, pedophobia confabulario observed in some forms of progressive amnesia (senile dementia, psychotic forms senilna-atrophic processes) and for certain forms paraphrenia Breda (for example, a fantastic delusions of grandeur). Numerous, diverse, unstable and continuously changing confabulate, false recognition of those around them and rassvetnet thinking characterize confabulatory confusion arising from various organic and vascular psychosis. In some infectious diseases and head injury may occur expansive confabulate with abundant confabulation and elevated mood. A kind of distorted memory - cryptomnesia - is that the blurring the distinction in the memories of the events in which the patient was in effect, and the events about which the patient only heard or read.