DEMENTIA. - More or less rapid and complete loss of the ideational patrimony already constituted, at a young age or more often after the full development of maturity, due to functional alterations or anatomical lesions of the psychic zones of the cerebral cortex. The faculty of controlling the emotions and the higher powers of the intelligence (logic, criticism) are particularly affected; the functional block or the focal destruction of the localization zones of determinate categories of sensory or psychomotor images contributes to its manifestation and aggravates the mental defect. D. differs from feeblemindedness, in which the disturbance of the intelligence is tied to the failed or insufficient development of the nervous centers.
With regard to causes: senile d. (tied to involutional processes proper to age), encephalomalacic d. (from softening and destruction of the central nervous elements, due to hemorrhages or obstructions of the cerebral vessels), syphilitic d. (from syphilitic lesions of the cerebral circulation, similar to those of cerebral arteriosclerosis, or from destruction of the cortical elements wrought by the spirochetes, as in paralytic d.), schizophrenic d. (v. SCHIZOFRENIA), epileptic d., etc. The clinical picture of d. is usually progressive and irreparable.
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DEMENTIA PARALYTICA PROGRESSIVA (GENERAL PARALYSIS, CHRONIC PERIENCEPHALITIS). - A nervous and more particularly mental disease, caused by the localization of the syphilis spirochete in the cerebral cortex; it affects mostly men who until then were able and perfectly sound of mind, of middle age (30-50 years), who in their youth contracted syphilis and treated it imperfectly or not at all. The course, though through fatally progressive pauses, in 40% of cases, even if well treated, leads to death within a few years (1-5) after having caused a complete dissolution of the intelligence and character, a full ruin of the entire physical organism.
The disease begins with a progressive and slow weakening of the intelligence, at first such as to be attributable to a simple neurasthenic form (apathy, inactive demeanor); later it develops into the picture of an increasingly manifest d., with the gradual disappearance of mnemonic traces, first the most recent, finally the most remote and personal ones (place of birth, marital status, number of children, profession, etc.). The disturbances of the affective sphere are very important (indifference to what happens in the environment and to one's own grave physical decline, which proceeds parallel to the intellectual one). Deceptive periods of pause may suggest recovery; but the disease fatally resumes its course to the ultimate consequences.
At intervals a characteristic psychic exaltation of a euphoric type may appear, whereby the patient, in spite of reality, is convinced of excellent, exuberant physical and intellectual conditions, assumes a smiling appearance, becomes loquacious, turbulent; in combination with the demented state, true forms of delirium of a megalomanic type develop in the patient; at other times, particularly in the early stages of the disease when mental conditions are still good, intelligent patients, aware of their state, may fall into such sadness as to be driven to suicide.
Characteristic of the morbid picture are the symptoms linked to lesions of the cortical motor zones, that is, the particular disturbances of speech and writing. The first, dysarthria, in advanced disease, renders language completely incomprehensible due to the profound modifications, transpositions, mutilations of syllables in words. The disturbances of writing (dysgraphia) reveal together the paralytic motor disorder and the mental alterations of the patient; in it appear irregularities of the graphic mark with irregular, trembling, uncertain letters, at times reduced to mere scrawls, while the ideational content of the writing becomes empty, puerile, meaningless, clearly denouncing the demented state of the patient.
Alongside the mental symptoms, in d. paralytica progressiva the nervous symptoms also take part: alterations of the pupillary and tendon reflexes, uncertain spastic gait (ataxia), grave alterations of sensation up to complete loss of it, disturbances affecting the bladder, in some cases lesions of the cerebral nerves with paralysis of the eyes, tongue, etc., particularly in cases in which lesions of the spinal cord also intervene (tabo-paralysis).
To assess the social gravity of the disease, it suffices to consider the percentage (3-5%) of individuals who, having contracted syphilis, fall ill with d. paralytica progressiva and, among those admitted to the asylum, the ratio (ca. 10%) of patients with d. paralytica progressiva to the totality of the mentally ill.
Antiluetic treatment, associated with the artificial provocation of febrile attacks, obtained by inoculating the malaria plasmodium (malariotherapy), can lead to recovery in 25-30% of patients, to a fair improvement in an equal percentage of patients.