Chapter VII: Study of the Motor Reaction

The general characters of the motor reaction constituting the objective manifestation of tic form the subject of previous analysis in the chapter on pathological physiology. It is our present intention to approach them from the semiological point of view.

To give a description of the motor disturbance of universal applicability is evidently to attempt the impossible. The modifications of functional acts are legion, and in the case of tic anomalies of muscular contraction vary not merely with the individual, but in the individual. Each tics after his own fashion; and no two tics are ever exactly interchangeable. As Trousseau was wont to say, "the disease in a sense forms part of the constitution of the person affected."

THE TYPE OF MOTOR REACTION--CLONIC TIC AND TONIC TIC

The motor reaction may be either _clonic_ or _tonic_ in type. Clonic tics are distinguished by more or less abrupt contractions, separated by longer or shorter intervals of relaxation or repose. The duration of a clonic tic convulsion may be exceedingly brief, though perhaps not so brief as the instantaneous "electric" twitches of a spasm, which have the extreme rapidity of pure reflex phenomena. Exception ought to be made for the face, no doubt, seeing that the suddenness of the movements in facial tic is precisely what complicates the diagnosis between it and facial spasm, as we shall see. In the limbs, the variations appear to stand in close relation to the nature of the primary factor, the mental condition of the patient, and the mode of reaction peculiar to him. The quickness with which the reaction occurs increases in proportion to the length of time the tic has existed, although once it has become habitual, any further change is rather in the direction of additional complexity.

Sometimes a relative deliberateness of execution raises suspicions as to the accuracy of the diagnosis. In the case of a child with several tics, one affecting the mouth in particular, Guinon was struck by the slowness of the muscular contractions.

To begin with (he says), the mouth was opened gradually, but as
soon at the limit of separation of the maxillæ was reached, it was
immediately closed, without remaining even for a moment in the
extended position, as one would have expected had there been a
tonic contraction of the infrahyoid muscles.

Cases of this kind, however, are not really instances of the tonic variety.

One of us has had the opportunity of observing a young woman afflicted with a curious combination of motor disorders, akin no less to the clonic form of tic than to the gesticulations of chorea and the undulatory movements of athetosis. Their resemblance to the clinical type described by Brissaud under the name of _variable chorea_ is noteworthy, a distinguishing feature, however, being the sluggishness of the muscular contractions, which may well be a reflex of the patient's mental inertness.

Mademoiselle R., a young woman twenty-six years old, is a small and
delicate creature with slender limbs and tapering fingers. She is
extremely myopic, but her general health is excellent, and there
is nothing to suggest that she is suffering from organic disease
of the nervous system. Apart from the fact that her parents are
rather "nervous," the family history is negative.

Since the age of twelve she has been subject to various tics of the
face and head. She wrinkles her forehead and moves her scalp to and
fro, and sometimes she turns her head slowly and steadily towards
the left side, raising her eyes up and to the left at the same
moment. Head and eyes forthwith resume their normal position. The
deliberateness of the act is altogether exceptional. If, however,
she happens to be wearing her hat--which is remarkable for its
size, weight, and unwieldiness--the gesture is repeated in a quick
and jerky manner. Any diversion, such as reading, knitting,
listening to a conversation, especially if she feels she is not
being noticed, will augment the intensity of the movements, which
the thought of being observed, or the awakening of her interest, or
rest in bed, or sleep, has the effect of abbreviating or checking.

Our earliest step was to confiscate the offending hat, and this had
the instantaneous result of diminishing the violence and frequency
of the tic, which the subsequent practice of appropriate exercises
entirely dispelled.

If now we direct our attention to the psychical aspect of the case,
we are struck with the goodness, devotion, and disinterestedness of
our patient. Her one concern is for the welfare of others, and she
is indifferent to the pleasures of literature, art, games, or even
work. All that is required of her she performs with docility, but
never with animation. The extent of her passiveness is seen in her
childlike acceptance of her parents' wishes. Her temperament is
neither gay nor sad, but merely dull. Indolence and maladroitness
predominate in all her actions, and reveal themselves in the
curious awkwardness and nonchalance that characterise the execution
of even the simplest movement. She is essentially of a very
unstable nature, but its torpidity is no less obvious than its
instability. If there is no abruptness in her acts, it is equally
true that she is never still. She cannot maintain any given
attitude; she cannot fix her gaze on any particular object. Her
restlessness is such that her position is changed from moment to
moment, however slowly and imperceptibly. Her eyes are only half
opened; as she speaks, her lips are scarcely seen to move.

It has been a laborious and protracted task to teach her to sit
motionless with her hands in front of her, and no less unremitting
effort has been required to make her open her mouth properly, or
turn her head naturally from side to side.

In some ways the endless movements of her hands and fingers--she
never ceases playing with her dress or her gloves or her
handkerchief--are vaguely reminiscent of those of athetosis, and on
the left side especially, if they become a little brisker, there
is slight hyperextension of the phalanges. She reads aloud in a
low, colourless, monotonous tone of voice, without punctuation or
accent, articulating the syllables defectively and slurring the
ends of the words. At the finish of each paragraph comes a halt, as
if from fatigue, and on command a fresh start is made with the same
careless indifference. As for the lower extremities, the tale is
identical. Mademoiselle R. cannot stand upright. She rests on
either one leg or the other. Her left foot is never flat on the
ground, but sometimes on the inner border, sometimes on the outer.
The faulty attitude is readily enough corrected, though she
declares she is ignorant of it. It is a sort of half clonic, half
tonic, tic of the foot, whose slowness is on a par with that of all
her other acts.

It is because clonic tics are so easily recognised that they are the most familiar, but we must not ignore another variety--viz. the _tonic tics_, corresponding to the tonic form of convulsion.

Tonic tic is of common occurrence in cases of mental torticollis. In that disease rotation of the head may be sustained for a considerable length of time without interruption, showing the permanent nature of the muscular contraction. Strictly speaking, we are concerned not with a sudden gesture, but with an attitude. Abundant evidence is forthcoming to substantiate its mental origin, and it may therefore be described as an attitude tic. Among other instances of tonic tics may be specified the affection of the masseters known as mental trismus (Raymond and Janet), or that continuous contraction of the orbicularis which keeps the eye half closed, though it may momentarily disappear under the influence of the will--a tonic blinking tic. O. and young J. have already supplied examples of attitude tics, and reference may further be made to another of our patients[49]:

Sometimes the mouth is drawn directly and completely to the left,
more usually to the right; at other times simultaneous contraction
of the upper and lower lips takes place, constituting a
sufficiently faithful reproduction of the grimace made by a child
in the attempt to refrain from crying; at other times still,
imperfect closure of the lids and upward deviation of the eyes bear
a resemblance to children's imitation of a blind man. Displacement
of the mouth to the right is the movement of longest duration, and
while it persists the patient is capable of stuttering speech,
without relaxing her lips. The other tics last but a few seconds,
while all vanish if she laughs or opens her mouth wide to exhibit
her tongue. They follow each other at irregular intervals, and
during the moments of rest the face resumes its normal expression.

Cruchet, as has been already remarked, has criticised the use of the term attitude tic, on the ground that the adoption of an attitude, however vicious it be, need not be the outcome of a convulsion. Doubtless; but it is no less true that a tonic convulsion may "take shape"--_e.g._ the _arc de cercle_ of hysteria, the phenomena of catatonia and catalepsy, etc. Of course if the word tic is to be synonymous with _intermittent_ twitching, then it is inapplicable in this class of case; but if our connotation of the term be accepted, we must find an expression that will serve to differentiate between tonic and clonic varieties. We are not aware of any particular advantage in describing the condition as a permanent contraction, for the obvious result of a permanent contraction, whether it be clenching of the jaws, occlusion of the eyelids, or rotation of the head, is the production of an attitude, a "position in which the body is kept" (Littré). No other designation could therefore be more appropriate than attitude tic, or could indeed be imagined, seeing that Cruchet himself ranges mental torticollis among the tics, and describes it as "an attitude of defence and of repose."

It may sometimes happen that the manifestations of stereotyped acts consist in the assumption of attitudes, but in spite of their affinity to the tics we deem it preferable to reserve the term "stereotyped attitude" or "akinetic stereotyped act" for cases where the motor reaction is clothed in the form of a normal movement. As it is inaccurate to describe as a tic a repeated gesture whose execution is normal in degree and in rapidity, so the mere immobility of a limb, or the prolonged contraction of a muscle, ought not to be called an attitude tic if the muscular effort does not differ from that which a healthy person would make to preserve the same position. In such circumstances we say that it is a stereotyped gesture or attitude. For the diagnosis of tic it is insufficient to establish the existence of a transient or permanent muscular contraction, and to note the inopportuneness of the movement; the contraction must be abnormal in itself, its abruptness unwonted and its intensity excessive--in short, it must be a convulsion; and finally, its repetition must be continued and exaggerated.

We have felt that some such explanation as the foregoing is required to justify our use of the term tonic or attitude tic, to whose close intimacy and association with the better-known type pathogeny and clinical observation alike bear witness. In any case such terms as myotonus or myoclonus are too comprehensive, in view of our present-day knowledge, to specify the particular motor affection with which we are concerned.

* * * * *

As a general rule it is only one part or segment of the body that is immobilised by a tonic tic, but in regard to the possibility of a general involvement, the following instance[50] may be cited, although we do not think it can be considered decisive:

A man thirty-two years old, who had recovered from a first attack
of mental torticollis, underwent a relapse in quite a different
form. If when walking with his head perfectly straight he were
asked to go round to the right, he instantly appeared to become
rooted to the spot and could not turn even his head in the required
direction; at the same time he felt a compression of his throat as
if he were being strangled, and for a few seconds he experienced
acute anguish. A moment later he was all right again, and his
action unimpeded.

Without going so far as to classify this incident as a tic, and without venturing to assert the existence of a _tic of immobility_, one cannot but be struck with its analogy to the attitude tics of which we have been speaking, and to catatonic conditions met with in the insane, of which too the pathogeny presents more than one point of similarity with that of this species of tic.

[In this connection reference may be made to certain conditions occasionally noted among those who tic--viz. a curious tendency to maintain abnormal positions of the limbs or trunks, and difficulty in or impossibility of relaxing various muscles (_catatonic aptitudes_). Patients are sometimes given to the exaggerated repetition of the ordinary movements of their members (_echokinesis_), as well as to imitation of the actions of others (_echomimia_). Such catatonic and echopraxic phenomena[51] are not confined to sufferers from tic, for they are encountered among psychopathic subjects generally, and indicate defect of cortical control--what is called by Brissaud "passive activity." These catatonic aptitudes may be discovered by resort to clinical tests, such as letting the arm fall from the horizontal position.[52]]

INTENSITY OF THE MOTOR REACTION

The muscular contraction varies considerably in intensity, in most cases exceeding that of the corresponding normal movement, and, especially in tonic tics, being often so powerful as to necessitate the exertion of great force to overcome it. Even though one's effort prove unavailing, however, it is only needful to distract the patient's attention to perform any and every passive movement with consummate ease.

In the case of S., any attempt to budge the head from its torticollic position on the left evokes strong muscular resistance; but engage him in conversation or otherwise divert his mind, and the difficulty soon vanishes. By similar means, the resistance awakened by sudden change of the direction of passive rotation will rapidly die down.

Occasionally the muscles brought into play surpass their fellows of the opposite side in size and power, this secondary hypertrophy being the natural sequel of repeated exercise. It was noted by Charcot that in rotatory tics the disused muscles atrophied, whereas the affected muscles hypertrophied, but they may do so only in appearance. The tonus of the muscles at the moment of examination may create differences inappreciable during relaxation. Sometimes one comes across such expressions as "paresis" or even "paralysis" of antagonistic muscles, and "contracture" of those in which the tic is localised. To draw a distinction between slight contracture of the latter and mild paresis of the former is a problem practically always insoluble. Opinion has been ever divided on this point; yet some, in their desire to harmonise the two, take up an eclectic position and do not hesitate to speak[53] of "paralytic contracture," or "mixed contracture, at once active and passive," a terminology by no means calculated to simplify the question, and one the discussion of which we do not care to pursue.

We should like, however, to allude to a matter of clinical observation that we frequently have had occasion to remark. What simulates muscular enfeeblement in the subject of tic is often nothing else than a want of accuracy and _adresse_ in the performance of a given movement. For instance:

S. enjoys robust health; his only trouble is a lack of accurate
control over his limbs. His execution of the most elementary
movements is incorrect. There is no tremor, no jerkiness, simply a
loss of the sense of position. He never knows whether he is holding
himself straight, whether his arms are exactly horizontal or his
shoulders symmetrical. Often he confuses right and left, and when
requested to perform some act on one side, he declares he is
tempted to perform it simultaneously on both. The order to fold his
arms and rotate the upper part of his body to the right evokes an
inconceivable display of contortions. In the attempt to bend his
head and body backward, fear of losing his balance causes him to
twist and turn about most strangely, and the remark that all this
he might avoid by merely putting one foot further back seems to
cause him infinite surprise.

Or again:

The absence of precision in Mademoiselle R.'s movements, her habit
of arresting the action before attaining the desired end, are not
to be ascribed to any feeling of discomfort, but to her ignorance
of the amplitude of her efforts, and of the position of her limbs.
Her acts are always feeble, hesitating, and curtailed, a curious
mixture of muscular languor and vigilance, "as if she were afraid
of breaking herself." She appears to be constantly seeking some new
position for herself, and to be as constantly oblivious of her
actual attitude. With eyes closed, however, she indicates the
relation of her limbs exactly.

Another example is furnished by the case of L., to which reference is made on p. 135.

There is no call to multiply instances. Enough has been said to demonstrate the frequent occurrence, if not of motor inco-ordination, at least of faulty orientation in space and of defective estimation in regard to the range and intensity of voluntary movements, among the subjects of tic. The topic is a very interesting and fruitful one, on which considerable light may be thrown by the application to it of the results of Pierre Bonnier's[54] remarkable studies on the sense of attitudes, a subject that we intend to develop on another occasion.

FREQUENCY AND RHYTHM--RHYTHMIC TIC

The frequency of the muscular contractions in tic is so very variable that it cannot be regarded as a distinctive feature, nor is there any evidence to show that it is rhythmical, as some would have us believe. Contrary to what obtains in tremor, there is no periodicity in the motor phenomena, even when the tic is based on derangement of a function whose manifestations are rhythmical, such as the function of respiration. Conditions described as rhythmic tics, or less well as rhythmic spasms, seem to form a group by themselves; probably they do not belong to the same family as the tics, indeed in some cases they are symptomatic of encephalic lesions, as in the _spasmus nutans_ of infants, or the rhythmic tics of idiots and imbeciles. In this connection the remarks of Noir are very pertinent:

We shall be well advised to refrain from drawing too absolute
conclusions in questions so difficult, where even the framing of an
hypothesis demands prolonged observation, but we cannot withstand
the temptation to note the co-existence of certain of these tics
with certain definite lesions recognisable post-mortem. This has
been done before us by our master Bourneville, who has on several
occasions made the diagnosis of chronic meningo-encephalitis,
cerebral sclerosis, etc., from this association of rocking,
rotation, and krouomanic movements with a special symptom-complex,
and verified it at the autopsy. Nevertheless, there is not always
an absolute correspondence between them, wherefore Bourneville,
with an altogether praiseworthy scientific reserve, has hesitated
to consider these tics as actual symptoms of the affections alluded
to, and we shall follow his prudent example.

To the combination of various rhythmical acts with hysteria we shall revert at a later stage. Under the title "rhythmic spasm" an interesting case has been reported at length by de Buck,[55] concerning a young woman, free of hysterical stigmata, in whom convulsive movements first appeared at the age of seven years.

When she had attained her nineteenth year she commenced to suffer
from attacks of anguish of some hours' duration, but disappearing
under the influence of sleep, in which she felt as though her
breathing were going to stop and she herself were about to die. On
the termination of these sensations some eighteen months later,
their place was taken by convulsive movements of the tongue, lips,
neck, trunk, left arm, diaphragm, pharynx, and muscles of
respiration. These consisted of clonic rhythmical twitches, each
preceded by an inspiration and succeeded by an expiratory
ejaculation, repeated fifty or sixty times a minute. During the
seizure the tongue was protruded and deviated to the left, the left
arm was raised, the head and trunk bent down and forward. All day
long the movements were continued with unflagging regularity. Rest
in bed was without effect, but they were dispelled by sleep.
Distraction and occupation exercised an inhibitory influence on
them, whereas voluntary control was both feeble and fleeting. In
the condition of the patient there was nothing else abnormal with
the exception of slow, monotonous, and syllabic speech. Her mental
development was perhaps a little immature, but signs of hysteria
were lacking, and all attempts at treatment by suggestion and
hypnotism failed of their object. Death ensued from pulmonary
tuberculosis.

De Buck observes that while the action of some of the muscular groups involved in the rhythmic spasm was, so to speak, purposive, the whole did not constitute any known, conscious, and logical movement. It may have been a species of tic, but the rhythmical sequence of the convulsions imparts to it a quite peculiar character.

ATTACKS

A further mark of the motor reaction is the circumstance that it ceases for a longer or shorter interval, independently of the tic's localisation, intensity, or form, the result being an alternating series of "attacks" and periods of respite. In different patients, and in the same patient, the number and the length of these attacks are as variable as are the spaces of rest that separate them. We remember a girl with a tic consisting in a toss of the head repeated perhaps fifteen times a minute, three or four occurring together at intervals of one or two seconds, and being succeeded by a relatively long pause. The effect of treatment was to modify the sequence entirely, and to reduce the tic to an isolated jerk reappearing not oftener than once in a quarter of an hour, and in itself constituting the attack. In another case the patient's head used to turn to the left, remain so for a moment, then resume its ordinary place. After a time of repose the tic began again, and even when the movements followed each other more rapidly, the intervening period was always appreciable. On the other hand, we have seen a youth afflicted with multiple tics which continued without intermission the whole day long; the attack lasted, strictly speaking, from morning to night, and any break in its continuity was altogether exceptional. It might then be more exact, perhaps, to use the epithet paroxysmal in reference to the external manifestations of tics, but it signifies little what word we employ provided we are familiar with the clinical facts.

The attacks vary with circumstances and environment. One of our patients remained quite free from them during a visit to the theatre. Tissié had a young patient who did not tic at all while on holiday, but the reopening of his classes was the signal for a fresh outbreak. Similarly, no rule whatever seems to govern the duration of the times of relief; they may never be longer than a few seconds, or they may run into months. In the face of these data we cannot supply further generalisations; it will be sufficient if we impress on ourselves the importance of one fundamental element in the constitution of tic--viz. its repetition.

LOCALISATION OF THE MOTOR REACTION--VARIABLE TICS--FIXED TICS

The localisation of the motor reaction in cases of tic is essentially physiological. In rare instances its sphere may be limited to a single muscle, if one muscle only be requisitioned for the performance of a functional act; but it is very much more usual to find several muscles contributing, whose synergic contractions fashion the movement of which the tic is a caricature. If the same effect is yielded by the action of either of two different muscles or groups of muscles, as in rotation of the head, and if one be hindered from fulfilling its function, the incidence of a tic originally located in it will promptly be transferred to the other. This is the explanation of the persistence of rotatory tics after exclusion of the sternomastoids by surgical means.

Two symmetrical muscles may be affected, as in tics of blinking and of affirmation, or a median muscle, such as the orbicularis oris. Much more frequently the tic is unilateral in its distribution, as, for instance, when it involves the face; in this respect its figuration as a functional disturbance is well exemplified, for expressional movements of the face are normally bilateral. A tic may settle itself on two mutually antagonistic muscles, and manifest its presence in the immobilisation of a limb or segment of a limb; or only a portion of a muscle may contract, as in the case of the deltoid or trapezius, which are composed of bundles anatomically associated but physiologically independent, and so capable of being functionally differentiated by voluntary education. Fibrillary contraction and tic have nothing in common.

Inasmuch as the muscles concerned are under voluntary control, and their contractions such as the will can effect, it follows that with adequate practice the movement of a tic can always be imitated, and in predisposed soil imitation tics may thus take root; it is not always feasible, on the other hand, to counterfeit a spasm.

Several functional muscular territories may be simultaneously affected, and several tics may follow one another in quick succession, the duration of any one tic on any one site being a more or less varying quantity.

We have already noted the occurrence of variable tics. They appear one day to disappear a few days later, and reappear again after another space. Weeks or months may elapse without any vestige of them, until they suddenly break forth again unheralded. As a general though not absolute rule, the younger the patient, the less stable his tics. Occasionally they are isolated, limited, and stationary, one of the most frequent of this kind being a tic of blinking, but the intimate alliance between the motor troubles and the mental level of the subject helps to explain why these tics of children are so changeable.

In the case of young J., for instance, it was shortly after
attaining his tenth year and entering school that first he began to
tic, and thenceforward, at unequal intervals, trunk, arms,
shoulders, legs, became in turn the seat of "movements of the
nerves," while other more definite tics were not slow in
developing.

When only six years old B. exhibited a respiratory tic, which
changed a year later to one of the tongue, and after another year
to one of the leg; at the age of twelve he used to nod his head in
affirmation, and this was eventually succeeded by movements of
negation, etc. He has since started a salaam tic, and finally a
torticollis with deviation of the eyes.

We may cite an analogous case from Grasset:

A young girl, who had had eye and mouth tics in childhood,
commenced at the age of fifteen to advance her right leg
involuntarily--a sort of tic which lasted several months and gave
place to paralysis of the same limb; for this affection was next
substituted a whistling tic, and then for a whole year she used
from time to time to give vent to a loud "Ah!" When she came under
observation she was suffering from a tic of salutation, with
retrocollic jerking of the head and shrugging of the right
shoulder.

One of our own patients furnished us with the following story:

The disease made its debut by a blinking tic of both eyes, whose
origin in the absence of any visual defect remained undetermined;
grimacing and distortion of the mouth were the next to appear, as
well as wrinkling of the nose and forehead, twitching of the
eyebrows and contraction of one platysma, sometimes even of the ear
muscles and the entire scalp. Then ensued up-and-down tossing of
the head, or rotation of it from right to left, and, later,
elevation and advancement of the shoulders, with restless agitation
of hands and arms. A former trick of his of biting his nails is
quite in abeyance at present; instead, he catches hold of his under
lip every moment and abrades its mucous membrane with his nails, so
much so that the lip is swollen and cracked like those of children
with nibbling tics. Some months ago he acquired the habit of giving
utterance to a soft little cry not unlike the sound made by a
guinea-pig.

One tic has succeeded another in an unbroken series. The facial
tics were more of the nature of grimaces, which the child amused
itself in repeating; no doubt the scratching of the lip was a
sequel to the desire of experiencing a new sensation, while the
movements of hands, arms, and shoulders were very variable and
different enough from the accompanying phenomena. No one of the
tics was at all of protracted duration; on the contrary, each was
fugitive and changeable, and therein presented a resemblance to the
child's mental status. In sleep they completely disappeared; in the
presence of strangers or if his interest was in any way aroused,
they quieted down, while they increased on holidays, during games,
or with physical fatigue.

It is clear that determination of the tic's localisation and mode can come only with the mental evolution of the patient, and that the transformation from the psychical inconsistency of childhood to the stability of the adult is paralleled by the change in the tic's manifestations as the scale of age is ascended. Any individual, whatever his years, who is in the stage of mental infantilism, will tic after the manner of a child, for the characters of a tic are dependent on the state of mind of its subject.