irreversible deterioration of mental activity, manifested mainly by a decreased ability to acquire knowledge, loss of previously acquired knowledge, emotional apathy, and behavioral changes.
Dementia may be congenital (oligophrenia) or acquired. The concept of dementia usually refers to acquired dementia, that is, dementia resulting from mental disease. Clinically, dementia may be total or partial. Total dementia is characterized by an impairment of the ability to make judgments and arrive at conclusions, a sharply decreased critical attitude toward one’s condition, a loss of individual personality features, and a predominance of a complacent attitude (as in the case of senile psychosis). The main symptom of partial (dysmnestic) dementia is a disturbance of memory accompanied by emotional instability, helplessness, and a weakening of mental activity (as in the case of vascular disease of the brain). In partial dementia, however, consciousness of one’s own incompetence is retained, and the personality does not lose its individuality to the degree that it does with total dementia. The irreversibility of dementia is to some extent conditional, as is demonstrated by the results of treatment for patients with Bayle’s disease. In addition, there is a special form of acute transitory dementia associated with certain febrile, toxic, and other psychoses. The characteristics of dementia depend on the disease that produces the mental deterioriation; among the diseases are epilepsy, schizophrenia, and alcoholism.
M. I. FOM’IANOV