TICS AND STEREOTYPED ACTS
WE have already, on more than one occasion, drawn attention to the phenomena known as stereotyped acts, demonstrating their intimate kinship with the tics and the frequent difficulty of establishing a differential diagnosis. To ensure precision of ideas and of terminology, we must restrict the expression to motor disturbances in which the characters of the muscular contraction are identical with those of normal acts. On this view many motor reactions are really classifiable as stereotyped acts, and among them are those denominated by Letulle "habit tics."
Stereotyped acts occur in normal individuals, and it may fairly be said there is no one but has his habitual gesture, his movement of predilection. As a matter of fact, a certain number of what Letulle calls co-ordinated tics belong to the group under consideration; others, no doubt, are genuine tics, and between the two may be found innumerable intermediate varieties.
From the diagnostic standpoint the stereotyped acts that occur in the course of mental disease, of which a conscientious study has recently been made by Cahen,[168] are highly instructive. He defines them as non-convulsive, co-ordinated attitudes or movements, resembling intentional or professional acts, repeated at frequent intervals and always in the same fashion, till their conscious and voluntary performance is replaced by a degree of subconscious automatism. In the case of the insane they are secondary to some delusion, and persist though the latter may disappear. Hence the patient may be incapable of explaining his movements and attitudes, however much he may persevere in their automatic execution—an evolutionary process akin to that of the tics.
A typical instance may be quoted from Séglas:
B. passed under observation in 1891, suffering from delusions of persecution, and not long afterwards it was noticed that from time to time he used to come to a halt in the courtyard, gaze at the sun, and rotate his hands round an imaginary axis. The reply he vouchsafed to interrogation on this point was that he was effecting the sun's revolution. At present, however, he has sunk into a state of dementia, and while the gesture continues he is unable to furnish any explanation of it.
Of course it is inadmissible to apply the term to co-ordinated acts that are neither conscious nor voluntary, such as the teeth grinding of the general paralytic, or the body oscillation of the idiot. Similarly one must differentiate them from impulsive seizures, abrupt irresistible motor explosions neither frequent nor prolonged.
A distinction has been drawn between akinetic (attitude) stereotyped acts and parakinetic (movement) stereotyped acts. As instances of the former we may give the following:
A woman reclines continuously in bed because she believes she has an infernal machine in her abdomen.
Another patient sits on the ground all day long, buttoning and unbuttoning his clothes.
An old gymnast maintains while he stands a professional attitude in which his head is raised, his right fist closed on his hip, his right leg crossed in front of the left, and his right foot elevated vertically.
Conditions such as these present the most intimate analogies to our attitude tics, though in the case of the latter there is always a more or less pronounced exaggeration of muscular contraction, a certain degree of tonic convulsion.
Parakinetic stereotyped acts are of common occurrence, and embrace every variety of movement or gesture.
A former acrobat leaps staircases, climbs railings, exercises his arms rhythmically and regularly, etc.
A patient promenades untiringly in the same corner and at the same pace.
An old engraver, now a dement, passes the day in reproducing in a more or less modified form certain actions associated with his former profession.
Alike in tics and in stereotyped acts, a time comes when the motor habit establishes itself, for no apparent reason or purpose; hence the co-existence of the two classes in chronic delusional insanity, in dementia precox, in catatonic states, in systematised mental disease of other forms, and in general paralysis.
Stereotyped acts may be the embodiment of ideas of persecution and of grandeur, or the outcome of mystical, hypochondriacal, and other states. A patient with delusions of persecution writhes because he is being "electrified." A hypochondriac rests motionless because he believes himself made of glass. A mystic maintains an attitude of genuflexion for hours at a time.
Obsessions also play a part in the genesis of the acts we have under consideration, but of all delusional ideas those of defence are the most fertile in this respect.
A patient under the care of A. Marie used to carry a fragment of glass between his teeth and other pieces beneath the soles of his feet, the idea being that they formed insulating cushions whereby to protect himself from the electricity of his enemies.
The suggestion was thrown out by Bresler that the movements of tic are often of a defensive character—that the disease, in fact, is a sort of "defence neurosis" linked to hyperexcitability of psychomotor centres. This theory is not unlike the view of hysteria taken by Brener and Freud, and as the movements themselves are usually of the nature of mimicry, Bresler has proposed the term mimische Krampfneurose.
In some cases of mental torticollis, the attitude assumed may be considered as a stereotyped act. Martin has recorded an example of torticollis in relation to melancholia. Another of his patients suffered from rotation of the head to the left, a position which could easily be rectified by asking the man to make the sign of the cross. The moment he put his finger on his forehead the displacement of the head was corrected. If, however, he were requested to look straight in front of him, he remained incapable of altering the vicious attitude, the reason he advanced being that he could no longer see the sun.
One cannot but be struck with the remarkable analogies to the cases given by Cohen. And it is worth remembering further, that sometimes mental torticollis degenerates into actual dementia.