Amnesia

AMNESIA (from the Greek a - negative particle and mneme - memory), a disorder of memory, expressed in various degrees of weakening of the latter. A distinction is made between congenital and acquired A., general and partial, i.e., affecting limited groups of representations (for example, aphasia). Congenital weakness of memory is observed in various types of congenital feeble-mindedness - from deep memory impairment in idiots to milder disorders in the mentally retarded. In this case, partial intensification of memory in a certain, limited area (musical memory) is sometimes encountered. Acquired A. is observed in organic diseases of the brain - progressive paralysis, senile dementia, polyneuritic psychosis (Korsakoff's disease) and others. In this case, A. is of a general nature and develops gradually, with the memory for recent events, names usually suffering in the initial period, then memory of feelings - sympathies and antipathies - is lost, and finally, memory of habitual actions perishes (Ribot's law). - Retrograde amnesia, expressed in the inability to reproduce impressions relating to a certain period before the onset of the disease, occurs after head injuries, in hysteria and in other diseases. Complete unconsciousness is observed in loss of consciousness - in fainting, epileptic seizure. Amnesia can be periodic in nature in so-called splitting of personality, in which the patient lives in two alternating states and in one of them does not remember the other. - Amnesic aphasia consists in the fact that patients who understand the speech of others and speak fluently themselves, hesitate when they must find the word ('symbol') denoting a given object. In conversation, they help themselves with descriptive forms. It is sufficient to prompt them with a letter, syllable, for them to 'automatically' complete the word. The essence of amnesic aphasia is the return to more 'concrete speech' due to the loss of the ability to 'categorical thinking'. It is caused by processes in the left temporal lobe (see Aphasia).