DEMENTIA. – More or less rapid and complete loss of the ideational patrimony already formed, occurring in youth or, more often, after the full development of maturity, owing to functional alterations or anatomical lesions of the psychic areas of the cerebral cortex. The faculty of controlling emotions and the higher powers of the intelligence (logic, criticism) are particularly affected; the functional blockage or focal destruction of the areas where particular categories of sensory or psychomotor images are localized contributes to the onset and aggravates the mental defect. D. differs from frenastenia, in which the disturbance of intelligence is connected with the absent or insufficient development of the nervous centres.
With regard to causes: senile d. (connected with involutionary processes proper to age), encephalomalacic d. (caused by the softening and destruction of central nervous elements, through haemorrhages or obstruction of cerebral vessels), syphilitic d. (caused by syphilitic lesions of the cerebral circulation, similar to those of cerebral arteriosclerosis, or by destruction of cortical elements effected by spirochaetes, as in paralytic d.), schizophrenic d. (v. SCHIZOFRENIA), epileptic d., etc. The clinical picture of d. is usually progressive and irreversible.
The disease begins with a progressive and slow weakening of intelligence, initially such that it may be attributed to a simple neurasthenic condition (apathy, an inactive demeanor); subsequently it develops into the picture of an increasingly manifest d., with the gradual disappearance of memory 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 especially important (indifference to what is happening in the environment and to the patient’s own grave physical decline, which proceeds in parallel with the intellectual decline). Deceptive periods of arrest may suggest recovery; but the disease inevitably resumes its course until its ultimate consequences.
At intervals, a characteristic psychic exaltation of a euphoric type may appear, whereby the patient, in defiance of reality, is convinced that he is in excellent and exuberant physical and intellectual condition, assumes a smiling appearance, and becomes talkative and turbulent; in combination with the demential state, genuine forms of delusion of a megalomaniacal type develop in the patient; at other times, particularly in the early stages of the disease, when mental faculties are still good, intelligent patients aware of their condition may fall into such sadness as to be driven to suicide.
Characteristic of the clinical picture are the symptoms connected with lesions of the motor cortical areas, namely the particular disturbances of speech and writing. The former, dysarthria, in advanced disease, renders speech completely incomprehensible through the profound modifications, transpositions, and mutilations of syllables within words. Disturbances of writing (dysgraphia) reveal both the paralytic motor disorder and the patient’s mental alterations; irregularities in the graphic form appear, with irregular, trembling, uncertain letters, at times reduced to mere scrawls, while the ideational content of the writing becomes empty, childish, and meaningless, clearly indicating the patient’s demential state.
Alongside the mental symptoms, in progressive paralytic d., nervous symptoms also occur: alterations of the pupillary and tendon reflexes, an uncertain spastic gait (ataxia), severe disturbances of sensation, up to its complete loss, bladder disorders, and, in some cases, lesions of the cranial 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 is enough to consider the percentage (3–5%) of individuals who, having contracted syphilis, develop progressive paralytic d., and, among those admitted to mental hospitals, the proportion (approximately 10%) of patients with progressive paralytic d. among the total number of mentally ill patients.
Antiluetic treatment, combined with the artificial induction of febrile attacks obtained by inoculating the malaria plasmodium (malarial therapy), may lead to recovery in 25–30% of patients and to a considerable improvement in an equal percentage of sufferers.