An intercurrent affection may act either as a deterrent or as a stimulus; with convalescence, however, there is usually a re-establishment of the mischief. The most potent influence over the phenomena of tic is wielded by a sense of well-being, to employ Janet's discriminating expression. Well-being is a panacea for the tiqueur no less than for the hysteric. The tic of the worried financier disappears, as we have had occasion to note, under the magic of a rise in stocks or a knowledge of solvency. The child's happiness is bound up in his freedom, which explains the cessation, in Tissié's little patient, of all convulsive movements during the holidays.
Much evidence is forthcoming to support these points, but we must admit that the why and wherefore of a tic's amelioration or aggravation often escape us, nor must we forget that both in the child and the adult spontaneous cure is not unknown.
As has been remarked, the evolution of tic does not lend itself to systematic description, but there are cases that form an exception, their course being regularly progressive. Strictly speaking, they are instances of Gilles de la Tourette's disease.
GILLES DE LA TOURETTE'S DISEASE
Under the title, "Study of a nervous affection characterised by motor inco-ordination, and accompanied with echolalia and coprolalia," Tourette[131] grouped together, in 1885, a certain number of cases presenting features in common and so enabling him to describe a morbid entity, specially remarkable for its progressive evolution. He was followed in the same line by Guinon, who supplied an account in nosographical form, and since then the disease has figured in all the text-books.
To obtain a schematic picture of the condition we shall borrow from Tourette's[132] last communication on the subject:
About the age of seven or eight a little boy or girl—for the sexes are affected equally—commonly with a wretched family history, begins to exhibit a series of tics. The attention of the parents is soon drawn to the fact, but they seldom give much heed at first, since the twitches are limited preferably to the facial musculature. At this stage, too, expiratory laryngeal noises are occasionally superadded.
The movements may be confined for a long time to the face, but under the influence of causes very difficult to determine they gradually invade the shoulders and the arms. First one shoulder is shrugged and then the other, then the trunk is inclined en masse to right or left; then the patient waves his hands or his arms, or bends backwards and forwards, or jumps up and down, flexing the knees alternately and tapping with his feet. The muscles of the larynx sometimes participate in the abnormal functioning, whence it is that many sufferers from tic give vent to quick expiratory "hems" and "ahs," which coincide often with the twitches of trunk and limbs.
The disease may be limited to this stage, but it is not uncommon to find, a few months or years after the beginning of the facial movements, that the inarticulate laryngeal sound becomes organised and develops in a particular direction, thus, in a sense, showing a pathognomonic value. Under the influence of causes whose action we are, in the majority of cases, powerless to appreciate, the patient gives vent one day to a word or short phrase of a quite special character, inasmuch as its meaning is always obscene. These words and phrases are exclaimed in a loud voice, without any attempt at restraint. There must be a complete absence of the moral sense where there is coprolalia such as this; at the moment of the ejaculation some irresistible psychical impulse must drive the patient to utter filthy words unreservedly and with no consideration for other people.
Another psychical stigma—echolalia—is occasionally, though less frequently, observed in these cases.