One of us has had a recent opportunity of examining a young woman whose obsessions and fixed ideas, and tics of face and neck, indicated an extreme degree of mental instability, in spite of intellectual power above the average, in whom trismus of this type was very obvious during eating and speaking. No effort, however concentrated, to open the mouth was then of any avail; yet, on the other hand, she could sing to perfection, and she could yawn, or show her tongue or her throat, in an entirely easy and normal fashion.
The appearance of this trismus during the performance of certain functional acts, and of these alone, is unequivocal evidence of its mental derivation.
TICS OF THE NECK—NODDING AND TOSSING TICS—TICS OF AFFIRMATION, NEGATION, AND SALUTATION
Regionally considered, the neck is second only to the face in furnishing the greatest number of tics. Convulsive movements of the neck muscles produce displacement of the head in all sorts of ways and directions, giving rise to clonic tics of affirmation, negation, and salutation, and to nodding tics, as well as to an important group of tonic tics which find expression in differing forms of torticollis. The latter are so distinctive in symptomatology and evolution, and have been the centre round which so much discussion has raged, that a chapter must be set apart for their special study.
Restricting ourselves for the present to such as are included in the category of clonic convulsions, we find here abrupt vertical or horizontal movements, as well as intermediate varieties compounded of elevation, depression, inclination, or rotation. The most ordinary kind is a sudden, brief jerk or toss of the head, repeated at irregular intervals, and followed by instantaneous resumption of the primary position.
Certain convulsive affections—for instance, the spasmus nutans of young children, the salaam tic, and what are known as "baboon movements"—are still rather obscure and in many cases seemingly not equivalent to tics. Their occasional association with strabismus or nystagmus constitutes a plea for their possible dependence on some encephalic lesion. In two cases under Oppenheim's observation the nodding spasm appeared solely in the hours of the night and during sleep. From want of more precise knowledge we must confine ourselves to the remark that conditions analogous to, though not identical with, the tics, in addition to others more specifically hysterical, have probably been incorporated with them.
It is a task of peculiar difficulty to determine the share in the final product to be apportioned to individual muscles, of which the sternomastoids, as being the most superficial and the most obvious, are apparently comprised the oftenest, though the trapezius and the muscles of the underlying strata, such as the splenius, complexus, and other smaller ones, may also assist.
According to Guinon, isolated contraction of one sternomastoid, whereby the head is rotated and inclined once or twice or several times consecutively, to the usual accompaniment of facial contortions, is very frequently to be noted. If there occur simultaneous contraction of the platysma, its fibres will be seen to line the cervical integuments longitudinally from the chin to the infraclavicular fossa. Synchronous involvement of the two sternomastoids will flex the head and approximate the chin almost to the sternum, but more commonly there is only a slight forward inclination of the head exactly similar to a gesture of assent. Extension and lateral deviation are less generally encountered.
Extreme variability characterises the exciting causes of these tics. It has been remarked more than once that insecurity of the headgear the subject happens to be wearing ought to be blamed; instead of readjustment with the hand, a little toss of the head will make the hat sit properly, and one need not search further afield for the germ of the patient's tic. We have been able to trace this mode of inauguration quite as conspicuously in young men as in young women. Prohibition of unstable head coverings and resort to exercises of immobilisation suffice for the tic's correction in early cases.
A not infrequent accessory symptom—viz. elevation of the corresponding shoulder—may have a similar origin in peripheral excitation connected with the patient's clothing. To escape the annoyance of a high and narrow collar, or, on the other hand, to experience an agreeable sensation by rubbing the skin, it is a very simple and a very easy matter to lean the head on the shoulder, and to raise the latter at the same time. The automatic reproduction of this gesture eventually ends in the formation of a tic which removal of the collar entirely fails to suppress. The first therapeutic indication, nevertheless, is to interdict the wearing of the unsuitable collar, and to recommend the adoption of others softer and more ample. Whatever be the opinion one holds on the mechanism of tic, the influence of peripheral stimuli is, according to Pierre Marie,[77] very considerable, and it is his invariable practice, in the case of youthful subjects, to impress on the parents the desirability of paying special attention to their children's clothing, and of discarding any article that is either stiff or heavy.