Of course any and every facial tic may occur by itself, but careful investigation will often reveal concomitant reactions of other muscular groups. The sniff that accompanies puckering of the nose indicates the engagement of the muscles of inspiration.
Facial tic, moreover, may be tonic as well as clonic, instances in point being closure of the eyelids, wrinkling of the forehead, twisting of the nose, distortion of the mouth, etc., of longer or shorter duration.
Any of the facial muscles may be attacked by tics. These commonly furnish an illustration of functional disturbance of mimicry, as in Oppenheim's cases of tic limited to the frontales, whereby astonishment or dismay was expressed, or in contraction of the superciliary muscles, which conveys a look of pain or of mournfulness. Spread to the scalp muscles may take place, causing a perpetual to-and-fro movement of the hair, of which O. and Miss R. supply examples. The platysma is sometimes the seat of a tic. One of Oppenheim's patients was a child with alternating twitches of his two platysmas; it is of interest to note he was able to contract either voluntarily. This condition is generally associated with similar contractions in other facial muscles, as in a case of facial and palpebral tic with platysma involvement recorded by Meirowitz,[62] or as in young M.
A not infrequent accompaniment is a shrug of one or both shoulders, due to synergic contraction of the trapezius. The resulting complex may be considered an act of mimicry in so far as it is an expression of disdain.
TICS OF THE EAR—AUDITORY TICS
The muscles of the external ear come often into play. One of our patients had a tic of the left ear, consisting in visible elevation of the pinna. A case of tic of the ear muscles has been described by Romberg, and another by Bernhardt, in the distribution of the occipital and posterior auricular nerves. Reference is made by Seeligmüller[63] to a ten-year-old girl suffering from unceasing involuntary contractions of the eyelids and of various head and neck muscles, with wrinkling of the forehead and movements of the ears. His original diagnosis of chorea was discredited by his subsequently learning that the child, in common with a younger sister and a brother, had for several years been exercising herself by making faces, and in particular by attempting to move her ears.
It is quite conceivable that certain middle-ear phenomena are comparable to the tics. O. used often to complain of hearing noises in his right ear, which came and went with his tics of face and neck. Now, it is well known that the probable explanation of the humming sound attending forcible closure of the orbiculares palpebrarum is the variation in labyrinthine tension due to the synergic contraction of the stapedius. This absolutely normal effect may be exaggerated by predisposed and preoccupied individuals into a sort of auditory tic.
TICS OF THE EYES—NICTITATION AND VISION TICS
For the sake of precision, tics of the eyes may be subdivided into eyelid tics and eyeball tics.
A. Eyelid Tics.—These, perhaps the commonest of all tics, may be either unilateral or bilateral. They consist simply in a palpitation of the upper lid, repeated at irregular intervals, and differing from ordinary blinking only in augmented frequency and abruptness. The form they usually assume is that of a wink, attributable in the first instance to contraction of the orbicularis, but supplemented by the zygomatics and muscles of the nose.