Chapter V: The Etiology of Tics

The circumstances favouring development of a tic in soil already prepared by psychical predisposition are manifold. Our studies in the pathogenesis of tic have illustrated the significance of exciting causes, so-called. We have seen how the motor part of the tic was originally directed to some definite object, and therefore provoked by some definite cause, and how the eventual disappearance of this cause does not justify the conclusion that it has never existed.

We shall be able to quote numerous instances in point when dealing with the different localisations assumed by the tics; what we wish to remark here is that the initial cause is by no means always easy to ascertain. The subjects of whom we are treating exhibit a vexatious tendency to invent a more or less fantastic etiology for themselves, and their statements cannot be accepted without rigorous investigation. Of any actual exciting cause they may be really ignorant, or more likely oblivious.

In this connection an important case is reported by Pierre Janet[30]:

A young man twenty-five years old was affected with a facial tic in
the shape of constant grimaces, accompanied by violent expirations
through one nostril. Six years of the condition had neither enabled
him to determine its origin nor brought him any relief. He
presented, in addition, the phenomena of automatic writing and was
the subject of somnambulism, and when in the latter state
explained that the tic arose from the effort to expel an irritating
nasal obstruction due to an epistaxis six years ago.

Needless to say (adds Janet), there never had been any obstruction
in the nose; the truth was that in the somnambulistic state he was
reminded of a subconscious fixed idea of which he was ordinarily
unaware.

Recognition of the causal factor, then, is not without value, as otherwise the tic's situation and form may rest inexplicable.

These exciting causes we shall discuss more closely at a subsequent stage, confining our attention for the present to one or two general considerations.

* * * * *

_Age._--Tics may occur at any period, except in infancy. "Nervous movements" appearing previous to the age of three or four cannot be tics, as has been made plain in the chapter on pathogeny. It is only with the development of psychical function--about the age of seven or eight--that revelation of its imperfection, if such exist, becomes possible.

Initiation or exacerbation of a tic is very frequent about the time of puberty, when both physical and mental evolution is peculiarly apt to suffer interruption.

_Sex._--Sex is without influence on the disease.

_Race._--In spite of the absence of precise statistics on the subject, the opinion that the tendency to tic increases with the advance of civilisation is not, we think, premature.

We have had the curiosity to interrogate several travellers familiar with different savage tribes of Central Africa, who, although notified beforehand to be on the look-out, declare they have practically never met with tic in negroes. These observations require to be confirmed.

It may be questioned if the level of mental attainment of such primitive peoples is sufficiently high to allow of the establishment of tics. Their occurrence in the lower animals has been recorded, it is true; but with our ignorance of what constitutes an animal tic, and until further information is forthcoming, it is prudent not to speculate on these matters. We must be content with the remark that savages and animals are less exposed than the civilised to circumstances facilitating the development of mental instability.

_Trauma_ and _infectious disease_ may provide the occasion for either the appearance or the disappearance of a tic, but of themselves they are incapable of originating the affection.

One of Noir's patients had a brother similarly afflicted, and a sister in whom an attack of bronchitis at the age of five was accompanied by tics of arm and head, which recurred subsequently in an exaggerated form during smallpox. On each of two occasions on which J. suffered from influenza his tics increased in violence and extent; while in the case of G. aggravation heralded the approach of measles.

Young M., on the other hand, remained free of all his face and head movements during the immobilisation of a fractured leg, with the cure of which his tics returned.

To disturbance of the reproductive organs, in particular to uterine disorders and even pregnancy (Gowers, Bernhardt), has been ascribed the onset of tic.

Of the possible influence of climate, season, and atmospheric change in general, precise information is lacking. Stormy weather or a falling barometer frequently exercises a depressing effect on the subjects of tic, but this is habitual in all neuropathic individuals. Oppenheim declares he has seen severe cases of convulsive tic follow an earthquake.

_Heredity._--To this Charcot used to attach the greatest importance. In every case of tic, he maintained,[31] however trivial, especially if attended with phenomena such as coprolalia, a hereditary element is discernible.

Similar heredity is of common occurrence. In Gintrac's cases, two brothers had the same facial tic. Blache's patients were three children in the same family. Delasiauve observed identical tics in brother and sister, and Piedagnel in mother and daughter. A father and two sons of whom Letulle has given an account all suffered from a tic of blinking. The same author has seen two brothers with a complex tic of face, scalp, arms, and diaphragm. More recently Tissié has recorded a series where a mother was affected with ocular tic, while the eldest son also had an ocular tic, which eventually spread to the face and was associated with a spasmodic cough; a younger son was likewise the subject of ocular tic.

A case has come under our notice of a young girl with a head-tossing tic which had been preceded by a variety of others now imitated by her youngest sister, such as sniffing, screwing of the face, shaking of the shoulders, abrupt pulling up of the garters, etc.

These and similar instances undoubtedly serve to show the effect of hereditary predisposition; but the element of imitation enters no less into the question, and the elimination of its influence, owing to family promiscuousness, is peculiarly arduous. To this point we shall revert immediately.

Dissimilar heredity, in any of its forms, neuropathic or psychopathic, is no less frequently met with, and emphasises the kinship of tic with almost all the psychoses and neuroses.

It is a matter of common observation for a _tiqueur's_ father to be a neuropath, his mother a hysteric, his brother an epileptic, or his grandfather a general paralytic or a maniac, while neurasthenia, hypochondriasis, psychasthenia, etc., or organic disease of the nervous system, may occur among the collaterals. A case has been under our care of a boy M., who has two brothers and one sister, all in good health. The sister bites her nails. The mother is normal, but excessively weak where her children are concerned. The father is neurasthenic, and the grandfather has trigeminal neuralgia.

Occasionally a family history of syphilis or alcoholism is forthcoming. Sometimes tic and psychical troubles alternate. Flatau[32] quotes a case of a mother with impulsions and a son with tics, and another of a mother and sister who tic, with a son possessed of fixed ideas.

In the subjects of tic and in their families, mental instability and intellectual superiority have repeatedly been conjoined. To refer again to the case of young J., no particular deviation from the normal was traceable on the part of any ancestor or relative on the paternal side, except that the father himself was unusually emotional and a prey to scruples; but the mother's whole family were either brilliantly clever or prematurely broken down, succumbing to "strokes" and paralyses of various kinds.

Many figures celebrated in history had their tic.

At the time of his early appearances Molière was held even in the
provinces to be a comedian of a very inferior order, owing perhaps
to a hiccough or throat tic of his leaving a disagreeable
impression of his acting on those who were not aware of its
existence.[33]

Brissaud recalls the curious picture of Peter the Great handed down to us by Saint-Simon[34]:

If he gave thought thereto, his mien became majestic and gracious,
else was it forbidding, and almost savage, his eyes and his face
occasionally distorted by a momentary tic that rendered his
expression wild and terrible.

Similarly with the Emperor Napoleon[35]:

His moments, or rather his long hours, of work and meditation were
characterised by the exhibition of a tic consisting in frequent and
rapid elevation of the right shoulder, which those who did not know
him sometimes interpreted as a sign of dissatisfaction and
disapproval, seeking uneasily wherein they could have failed to
please him.

Cases of tic in the descendants of great men are far from rare; we have met with several instances.

Among etiological factors of a general description, the rôle played by _imitation_ is all-important, especially in the young. Mimicry is strong in the child's nature, and bad habits are quickly contracted. Should he be tainted with nervous weakness in addition, he is apt to tic on the slenderest pretext, in which case to encounter, or still more to be associated with, the subject of a tic would be the direst of misfortunes.

That such a contingency should arise is not essential. A novel gesture on the part of any one catches the child's attention, and he forthwith attempts its reproduction, finding therein a source of complacent satisfaction. On the morrow the movement is repeated, and again, till it oversteps the bounds of habit and enters the realm of tic.

Cruchet concedes this to be a possible though by no means invariable mode of tic production, for the reason that the unconscious, or, more correctly, subconscious--polygonal, if you will--nature of imitation is undeniable, indeed self-evident.

Without entering into too great detail, it may not be amiss to examine this contention.

To imitate, in Littré's definition, is "to seek to reproduce what another is doing." How such an act is to be accomplished without the co-operation of the will we cannot conceive. Its duration being so brief, our recollection of the conscious stage may be very imperfect, but that is no ground for denying its reality. Involuntary execution of a gesture to-day does not exclude the possibility of its voluntary execution yesterday. If we find accurate reconstitution of the steps in our own habitual mental processes impracticable, _a fortiori_ ought we to question the likelihood of our gaining full insight into the mechanism of the processes of others.

It is no doubt this perplexity which has induced Cruchet to regard the simple convulsive tic as the sole manifestation of the disease. On his own admission, nevertheless, this simple convulsive tic is of exceptional occurrence, apart from children, in whom mental trouble is conspicuous by its absence.

But the psychical disorders of infancy, however embryonic they be, are none the less real. Their insignificance may hinder their recognition, yet they are often the prelude to graver and more definite anomalies in later life. And if their detection demands painstaking study and repeated interrogation, fruitless results may very well mean that the investigation was not sufficiently thorough.

Moreover, the view that regards imitation as a prolific element in the genesis of tics has met with widespread acceptance.

The onset of the disease (says Guinon) is sometimes the consequence
of the patient's partiality for mimicry. Contact with an affected
person supplies the occasion. His first experience is a sort of
constant preoccupation; the other's grimace is ever before his
eyes, inviting imitation; at length he suddenly yields to the
obsession, and his tic is in the making.

Reference has already been made to a case of Tissié's,[36] where an eight-year-old child acquired from its mother an ocular tic, which a second child imitated in its turn. The cure of the latter was followed with the cure of the two others, _by imitation_.

The word "echokinesia" was imagined by Charcot to specify the inclination some people show to copy what they see others doing. It has also received the names of "mimicism" and "imitation neurosis." To quote Guinon again:

The movements most closely and most infallibly mimicked are facial.
These the patient either is driven actually to reproduce, or feels
impelled to reproduce, without allowing the impulse to pass into
action. Simple and circumscribed gestures involving the limbs are
similarly, if less frequently, the object of imitation. Such tricks
as rubbing the nose or cheek or some other part, or stooping as if
to pick up something on the ground, may be counterfeited in their
entirety, though at other times the movement is only initiated.

Echokinesia may be considered a motor disturbance analogous and akin to tic, but distinguished by the fact that it occurs exclusively during the performance, and as the reproduction, of some movement executed by another. It is true, of course, a genuine tic may be a reminiscence of some gesticulation, but it is quite independent of time and place.

A similar difference exists between echolalia--the habit of repeating another's sounds or words at the moment of their ejaculation--and tics of phonation or of language; the latter are always ill-timed and inappropriate, though they may have had their origin in acts of imitation.

It has become classical to draw a comparison between these echokinesic phenomena and the observations of O'Brien apropos of _latah_ among the Malays.

A sailor on board a boat will pick up a piece of wood and proceed
to rock it as if it were a child, whereupon a _latah_ standing
alongside commences to rock the infant he holds in his arms. The
sailor then throws the piece of wood on to the deck, and the
_latah_ promptly follows suit with the baby (Guinon).

This is echokinesia carried to an extreme, revealing a complete absence of inhibition from the higher psychical functions.

Prominent among influences calculated to facilitate the evolution of tics is the patient's environment, more particularly where children are concerned.

The parents are often disposed to be deplorably "fond." Their ignorance or their thoughtlessness permits the installation of obnoxious habits and fosters their growth into tics. Any endeavour after suppression usually serves to expose the inadequacy of the family authority to exercise control and compel obedience. For the watchful discipline that should curb all such childish tricks and caprices is unfortunately substituted a disastrous indulgence that only stimulates the development of these embryonic tics. It should not be forgotten, moreover, that the mental instability of the fathers is visited upon the children in the guise of a certain aptitude for psychical anomalies.

The accompanying case supplies conclusive evidence of the mischief wrought by weakminded parents, and of the calamitous results of hereditary predisposition and bad example combined.

S.'s mother is a lady of over fifty, who spends her leisure hours
in writing novels, and who suffers from different varieties of
phobia. In the first place, she has an absurd fear of cats and
dogs. When she goes out, a maid follows at several yards' distance
to prevent the approach of any dog from the rear; and if she is
driving, the same precautions are observed.

Her dread of chest complaints is equally extravagant. A cold is her
bugbear, a draught her _bête noire_. In the intervals of her
literary labour she occupies herself with seeing that all doors and
windows are properly shut. The room temperature is maintained at
68° F. at least.

Since her husband's death her devotion to her son's education has
been fatal to his best interests. Her unfailing solicitude for his
health, her constant terror of accident and illness, have reduced
volitional effort in him to a minimum, and under this régime of
tyrannical affection he has been as delicately nurtured as a young
girl. Even at the age of thirty he must be indoors at night by ten
o'clock, and a few minutes' delay will bring his mother to a state
bordering on frenzy, and end in the dispatch of some one to seek
him; whence all sorts of domestic discussions, and quarrels, and
"scenes," with tears and mutual recrimination.

Little wonder then, with such an example, that, in spite of his own
robust health, S. evinces the same senseless fear of chills and
colds and currents of air, and tries the doors and windows so
incessantly and so violently withal that they have to be repaired
almost every month. In his own room they have been doubled and
padded. His anxiety to avoid catching cold actually leads him to
weigh the samples of cloth submitted to him, to ensure that his
next suit of clothes will be of the same weight as his last.

With all this excess of tenderness, S.'s mother does not always err
on the side of leniency. On the contrary, punishment is apportioned
for the most trivial fault, although it is only necessary on S.'s
part to simulate illness for his mother at once to yield to his
most ridiculous caprice.

S. suffers from a rotatory tic of the head, which he attributes to
a blow on the neck once administered by his mother by way of
chastisement; but it may very well be questioned whether the
torticollis was not rather a clever imposition intended to soften
the mother's heart and bring about her repudiation of corporal
punishment.

The case of J. is no less instructive, since he came of a family of veritable syphilophobes whose extraordinary frailties and sentimentalities contributed not a little to the progress of his disease.

A glimpse into the domestic life of L. is equally illuminating.

L. is an only child, who from infancy has usurped her parents'
attention. Their uneasiness lest her "nervous movements" should
prove detrimental to her general health is the explanation of her
highly irregular attendance at school and of repeated holidaying.
She may not go out alone, as her "incantations" are liable to
arrest her in the middle of the street; at the same time lack of
control over her legs may endanger her safety, and erratic arm
gestures render the aid of a stick or umbrella useless.

To add to her misfortunes, her head has now begun to rotate to the
right. She used four times a day to cross the narrow and little
frequented road that separated her father's house from her place of
employment; but since her last accident she has remained strictly
within doors, trifling away the time in a chair, and finding in the
petty life of a side-street all that she wants to attract her gaze
or arouse her interest.

In this microcosm her father has been reduced to the position of a
slave. He anticipates her slightest want and indulges her most
fanciful whim; his commiseration for her woes is only equalled by
his unselfishness in foregoing his own pleasure and his ingenuity
in vindicating her weaknesses. In short, his ready acceptance of
his daughter's instability argues a lack of mental balance on his
own part.

Brain fatigue is another element in the formation of tics whose influence ought not to be underestimated. In the case of young D., nineteen years old, a clucking tic supervened during the period of preparation for an examination, to disappear at its close.

No less fruitful are anguish, anxiety, worry, disappointment, as will freely be conceded. Any prolonged concentration of the attention on a particular act or a particular idea presupposes a concomitant weakening of inhibitory power over other acts and ideas, which then become corrupt and inopportune, are incapable of further repression, and blossom into tics.

Indolence, too--the mother of all the vices, according to the adage--favours the outbreak of tics, and accelerates their growth. The idle patient's thoughts are all for his tic; its perfecting taxes his inventiveness.

Mention may be made in passing of the effect of "professional movements" in predisposing to the subsequent apparition of a tic in the muscles concerned. We have already alluded to the relation between tics and certain cramps or occupation neuroses, and we shall refer to the topic again at a later stage.

It would appear that even the memory of a familiar gesture sometimes suffices to initiate the condition: witness Grasset's case of post-professional colporteur tic, where the subject reproduced the movement of swinging a bag over his shoulder, a souvenir of his former avocation.[37]

A final example, none the less instructive though it occur in lay literature, may be cited from Alfred de Vigny[38]:

With a child's delight the worthy battalion commander gravely made
ready to speak. He readjusted his polished shako on his head, and
gave that twitch of the shoulder appreciated only by such as have
served in the infantry--that twitch which is meant to raise the
knapsack and momentarily to lighten its load; it is a trick of the
soldier's which with his elevation to officer's rank becomes a tic.
Another sip of wine followed this convulsive gesture, a kick of
encouragement in the little donkey's stomach, and he began....

The description could not have been more accurate. The passage from the voluntary to the involuntary--the kick too may have been a tic--and the obvious infantile traits in the old gentleman's character, make the picture remarkably complete.

Apart, however, from the causes we have just enumerated, and others to be noticed below, we must emphasise the fact once again that mental predisposition is a _sine qua non_ for the development of tic.