Tics and Their Treatment

by Henry Meige; E. Feindel

Innumerable examples of this condition have been described and various theories elaborated. Apart from such cases, it is a matter of common observation that if any one be asked to write synchronously with the two hands, his left hand will tend spontaneously to adopt the mirror form.[232] The experiment may be tried on some one who has never made the attempt to write with the left hand, and has never heard of mirror writing. Ask him to abandon his left hand completely to the movements it may be constrained to fashion while the right hand is tracing the required words, and let his eyes be closed; in practically every case the left will make mirror characters. It may therefore be contended that mirror writing is the natural writing of the left hand, an opinion supported by Vogt, Durand, etc., and more recently by Ballet,[233] who remarks that this variety of writing for the left hand is natural in left-handed people who have not been influenced by education.

The actual form of the characters is of little significance. We have often repeated the experiment and substituted Greek, German, typographic and stenographic letters, but always with the same result. It is perhaps worthy of note that in simultaneous writing considerable modification of the letters traced by the right hand occurs; they become hesitating and childish; the lines are sinuous and irregular, and the characters themselves ill distinguished. The same holds good for drawings.

On the other hand, the first attempt of the left to make mirror writing to order is frequently laborious. Mingled with true mirror characters will be found ordinary letters automatically traced, for automatism of left-hand movements is not the inevitable sequel of automatism of right-hand movements. From time to time the visual image of a normal letter rises in the mind, an image which does not correspond to that which the hand is endeavouring to express, whence doubt, reflection, arrest, and, usually, error. If, however, the subject allows his left hand to write, without preoccupying himself with the shape of the letters it is making, or with his eyes shut, automatism reasserts its sway and mirror writing results.

Of course a person who is asked for the first time to use his left hand in writing may force himself to trace ordinary characters, but to do so he must evoke the visual image of each letter and seek to reproduce the contours of this image slowly, yet often inaccurately. There is nothing automatic in this. Hence it is that ordinary writing with the left hand demands prolonged education and patient effort, and may never attain any rapidity, whereas mirror writing with the same hand is acquired with facility in a more or less automatic manner.

It may well be that the natural left-hand mirror writing of which we are speaking is a purely motor phenomenon, since the calling up of the visual images of letters, so far from proving of assistance, is calculated rather to obscure and hamper it.

It has been pointed out by Ballet that variations in the aptitude for left-hand mirror writing exist, especially in the case of those who cannot write without the aid of the visual image of letters. Since they copy this image in using the right hand for caligraphical purposes, they are tempted to do the same when the left is in use. In fact, the facility with which one learns mirror writing seems to depend on one's power of writing without recourse to these images. The explanation of the ease with which the left hand reproduces, in the guise of mirror writing, the movements of the other, is to be sought in the symmetrical arrangement of the muscles in relation round the body axis. Physiologists tell us, further, that the simultaneous contraction of two symmetrical muscles is more readily attained than that of two asymmetrical muscles. The law of symmetry and the law of least effort correspond.

What is true of writing is no less true of all other forms of motor activity. In physical exercises the surest results are achieved by the synchronous contractions of symmetrical muscles, whereas education is much more arduous should this lesson from experience be ignored. For instance, nothing is easier than to make the arms describe circles in the same direction, but rotation in opposite directions is very difficult. Few people can revolve their thumbs in opposite ways. This is a matter of common observation among teachers of physical culture. The rapidity with which the action of swimming can be learned is in striking contrast to the slowness with which the art of fencing is apprehended. Little effort is required of the music beginner if his pianoforte exercises demand the activity of symmetrical muscles for their execution; on the other hand, the playing of a scale by the two hands in unison comes only with long practice, since it entails the simultaneous use of asymmetrical muscles.

Facts such as these are of more than passing interest. One cannot afford to neglect their import where muscular education is concerned, whatever be its nature, whatever be its object. Yet there is an unfortunate tendency to concentrate attention on the development of the skill of one arm only, and that the right. Sometimes the use of the left arm for certain purposes is criticised adversely, and of course most people are congenitally less able to work with it. But habit, example, and even fashion, combine to render the right arm preponderant in everything, to the detriment of the other. It is a common occurrence to attribute awkwardness to this left arm, when its inferiority is really nothing else than a sign of faulty education. In many cases the left is as good as the right; its apparent gaucherie is because of its attempt at executing movements which are similar to those of the right, instead of those which are correspondingly opposite.

Thus experience shows that the education of the right upper limb is reflected on the left upper limb, although the subject may be sublimely ignorant of the fact. But though this influence be latent, it is none the less real, and may prove of service if occasion arise. Weber, Fechner, and Féré[234] have all devoted attention to this subject.

From the therapeutic point of view, considerable significance attaches to these facts. Temporary disablement of the right arm, such as follows fracture or arthritis or writers' cramp, need not be disconcerting, for the patient can proceed to utilise the faculty for mirror writing which his left hand has unconsciously acquired. In all affections which are accompanied by troubles of motility it is an excellent plan to apply the prescribed muscular exercises to both sides of the body, and the regularity with which they are performed on the sound side will have a corrective influence on the mirror movements of the affected side. We assume, of course, that there is no irremediable destructive lesion which interferes with the continuity of paths joining functional centres, otherwise the education of the normal limbs could not be expected to produce any beneficial effect on the other. It is especially in motor disorders of functional origin that mirror movements prove useful, and the frequent unilaterality of these disorders readily allows of the institution of a re-educative mirror drill. Speaking generally, the faculty of writing supplies us with the best means of attaining our end, for the variety of exercises it offers is likely to rivet the patient's attention, and he has proofs of his progress under his eyes. The goal in view is not, of course, the attainment of caligraphical perfection—the subjects of tic are seldom guilty of bad penmanship; but the execution of the required movements demands a voluntary constraint that cannot but be profitable.