GENERAL SEMEIOLOGY OF DISEASES OF THE NERVOUS SYSTEM; DATA OF DIAGNOSIS.
BY E. C. SEGUIN, M.D.
I. Psychic Symptoms.
ABNORMAL EMOTIONAL STATES.—Emotional manifestations, spontaneous or provoked from without, are, in the civilized adult, held in check directly or indirectly by the will, or by so-called strength of character. Extreme variations are allowed as being within the normal, from the stupidity of the peasant and the impassability of the hero to the sensitiveness and almost unrestrained reactions of the child or of the artist. Each individual must be judged by his own and his racial and family standards in this respect. It is more particularly when the dulness or over-active state observed is in contrast with the subject's habitual demeanor that the condition is called pathological.
Emotional dulness, or the complete absence of any emotional manifestation, may depend upon (1) diminished sensibility to external influences; (2) sluggishness of cerebral action, more especially in the range of sensori-ideal processes, or to general want of intelligence; (3) absorption of the subject's cerebral powers in some special object, real or delusive. The first form is illustrated in various grades of idiocy and backwardness; the second, in fatigue, prostration, and in conditions of dementia; the third is well exemplified in cases of insanity where the patient is devoted to one delusion or dominated by hallucinations (melancholia attonita), in which case the subject may be told the most painful news, insulted most grievously, or threatened fearfully without manifesting grief, anger, or fear. In some instances absolutely no emotional life can be detected.
Emotional exaltation may be due to (1) increased sensibility to external influences; (2) to deficient self-control. The first condition is illustrated in neurasthenic and hysterical subjects and in forms of mania: slight or almost imperceptible provocations call forth reaction, a noise causes fear, a look anger or tears, etc.; the second mechanism is apparent in diseases (dementia paralytica) where the cerebral hemispheres are extensively diseased and the cerebral power lessened (more especially is this the case where the right hemisphere is injured), and in cases of simple debility or asthenia, as when we see a previously mentally strong man shed tears or start most easily in convalescence from acute disease.
It may also be stated, in general terms, that the emotions are manifested in inverse ratio to the subject's mental or volitional power. Psychologically, the emotions are intimately related, on the one hand, with sensory functions, and on the other with more purely mental functions. Anatomically, it is probable that emotions are generated in basal ganglia of the brain (thalami optici and ganglion pontis), in close association with the sensory areas of the cortex cerebri, while the volitional, inhibitory power is derived from regions of the cortex situated frontad. Clinically, we meet with abnormal emotional states in a great many diseases of the nervous system, more especially in hysteria, neurasthenia, and insanity.