we curl our moustache, we twist our beard, we scratch our forehead, we rub our chin, we nod our head, we fidget with our fingers in reading, speaking, reciting – in any mental or physical exercise requiring our attention we reveal innumerable little oddities of movement; but let our thoughts be directed for an instant to these gestures of distraction, and they disappear forthwith, to reappear afresh when we are absorbed in our work again. Charcot used to twist his hair round his index finger so intricately that to disentangle the finger one day a lock of hair had actually to be cut off. It was a trick of his, not a tic.
In the case of the latter, leisure of mind and body is the signal for the apparition of the inopportune movements. Any form of effort demanding the attention will, as a general rule, lessen their frequency or abolish them altogether.
Trousseau quotes the case of a young girl afflicted with severe tic who could play through any piece on the piano without the slightest interruption. Guinon similarly has known cases, one of whom could juggle accurately with knives, and another whose infirmity did not prevent her from taking a successful part in operatic ballet. Young L. is passionately fond of dancing, but he never tics in the ballroom. O. is an excellent amateur billiard player and never handicapped by his tic when playing, or, for that matter, when fishing or fencing; but if his attention be not thus absorbed, it is only with the utmost difficulty that he can master his tic.
We all have met the young man who cannot strike a ball at tennis without protruding his tongue at the same moment; his partner bites his lips at any difficult stroke. At other times neither betrays the slightest grimace; neither is conscious of any effort in maintaining repose. The occurrence of these movements during active concentration of the attention, and the absence of either difficulty or distress in checking them, justify their classification as stereotyped acts, in subjects psychically normal.
Tic is a pathological habit, to use Brissaud's phrase, and its description as a habit disease is in harmony with the facts. We must expect, of course, to meet every intermediate variety between the bad habit and the true tic, but this need not deter us from drawing the above-noted distinction, the application of which will be found not without value in the great majority of instances.
TIC AND IDEA
As we have already seen, a peripheral stimulus may originate a cortical reflex whose expression is a motor reaction, or the reaction may take place where the stimulus is entirely cortical; in other words, an idea may be the starting-point of a movement which may in its turn degenerate into a tic. All that has been already said of these phenomena is applicable to this movement of ideational origin. It too will be transformed into a tic when it is repeated without exciting cause and for no definite end, when its reiteration becomes imperious and irresistible, its suppression accompanied with malaise and its execution with relief.
Tics of this sort are numerous enough. "To think an act," as Charcot used to say, following Herbert Spencer and Bain, "is already to accomplish it. When we think of the movement, say of extension of the hand, we have already sketched it in our minds; and, should the idea be too strong, we execute it."
In this connection Grasset most appropriately cites the fact that the peoples of mid-France evince a peculiar aptitude for mimicking by suitable gesture the various ideas which occur in the course of conversation. "You will always succeed," he says, "with the following little experiment. In a drawing-room ask ten individuals consecutively to tell you what a rattle (crécelle) is. The answer will in every case be accompanied by a gesture expressive of an object that turns. To think an act is already to perform it; the thought and the gesture are wellnigh inseparable."
The truth of this observation is not a question of geography. Examples are met with on every hand. It is a law, abundant evidence for which is furnished by all who tic. But however exuberant be accompanying movements of explanation, they must present the additional features of inappositeness and irresistibility to be denominated tics.
A case that has come under our own notice is worth mentioning because of its peculiarity and instructiveness. The patient was an artistic, well-educated, and well-travelled man, gifted to a remarkable degree with the faculty of assimilation. Apart from genuine tics in the shape of sudden jerks of face, arm, or leg, he had acquired the trick of accompanying his conversation with a peculiar mimicry of its content. Not satisfied with providing a gesture for nearly every word, he divided the words themselves into syllables for each of which he had an appropriate action, whence arose a series of mimicry puns of most unexpected effect.
For instance, during the enunciation of the following sentence, "We were on a paddle steamer, with captain, commissaire, and doctor," he first of all imitated the movement of paddles; he then put his hand, with three fingers apart, to his forehead (the captain's cap has three lace bands); to mimic the word commissaire he shook hands with himself (commissaire—comme il serre); to express the word doctor he pretended to touch imaginary breasts on his body (médecin—mes deux seins); and so on throughout all his conversation.
Voluntary execution of these puns had been succeeded by complete automatism, yet they were not tics, because, however singular the mimicry, it was appropriate; whereas his facial grimaces, the shrugging of his shoulders, the tapping of his heels, repeated every minute for no reason or purpose, were real tics.
If, when asked what a rattle is, we make a turning movement with our hand, or if when asked to explain the word brandebourg we indicate an imaginary arrangement of braid on our coat – these two experiments always succeed – we are attempting to express an idea by mimicry at the actual moment of its arising in the mind; but the subject of a tic – which may primarily have been the representation by mimicry of an idea – continues the gesture long after the idea which provoked it has vanished.
A woman speaking with animation at a telephone will make with face or hand a thousand useless gestures, useless since her friend cannot see them, but they are not tics, even though they may be justly described as functional, automatic, superfluous, and inopportune. If we are normally constituted, we betray a pleasant idea by a smile, we express our conviction by an appropriate gesture of affirmation; if we smile or gesticulate with no motive for doing either, we have begun to tic. It is not sufficient that the act be untimely at the moment of execution; we must be persuaded that it no longer stands in any relation to the idea which called it forth at the first, and that its repetition is excessive, its inappositeness constant, its performance urgent, and its inhibition transient, before we can say it is a tic.
Should the cortex be functioning harmoniously, afferent impulse and efferent reaction stand in due proportion one to the other; but any disturbance of psychical equilibrium —e. g. the fixity of some idea combined with inhibitory weakness – will effect a corresponding disturbance on the motor side. Charcot used to speak of tics of the mind revealing themselves by tics of the body. Fear may elicit a movement of defence, to persist as a tic after the exciting cause has vanished.
It is of course quite incorrect to say that each and every motor reaction to a pathological idea is a tic. The psychasthenic who in his fear of draughts shakes the door-knob a hundred times a day to make sure the door is shut, is not a martyr to tic; in spite of the absurdity of his action, it is logically connected with the idea that originated it, and it is the idea which is absurd. To make an involuntary movement of defence against some purely imaginary ill, on the other hand, and to continue when all fear is past, is to tic.
In practice it may not always be a simple matter to uphold the distinction, but some such demarcation of the tic's limits is called for if we are to avoid its being applied to any act performed under the compulsion of a pathological mental state.
In its mildest form the mental trouble may consist of an ordinary psychomotor hallucination, but if it be not projected as an objective phenomenon it does not deserve to be called a tic. One of Séglas's patients met a choreic woman undergoing electrical treatment in the same room as herself; on leaving she felt as though her own right arm were the seat of spasmodic movements similar to those of the choreic patient, but as they did not betray themselves by any external sign they cannot be considered tics.
The exteriorisation of the hallucinatory phenomenon suffices at once to bring it within the scope of our definition. Innumerable tics arise in this way, provoked, mayhap, by some or other insignificant psychomotor hallucination.