How, then, is this localised convulsive movement to be designated? Is it a tic or is it a spasm?
The march of the disease, its painlessness, the absence of any reaction in sleep, the success of the little laryngeal trick, the inhibitory effect of the will, the definite influence of attention, distraction, in short of the psychical condition of the moment—all plead in favour of its classification in the former category. On the other hand, we cannot shut our eyes to the fact of the pre-existence of specific organic disease, and, moreover, the spasm is strictly confined to the anatomical distribution of the facial nerve. Even in periods of repose there is a certain amount of fibrillation on that side. On these counts are we to hazard the diagnosis of facial trophoneurosis?
A subsequent opportunity of examining the same patient served to confirm the diagnosis of spasm secondary to facial dystrophy, and treatment failed to make any impression on the condition.
Our object in giving these cases has been to point out the difficulties in the way of diagnosis, especially where spasm is superadded to a mental state that itself predisposes to tic. The wisest plan in many instances is to confine oneself to a description of the symptoms and to tabulate the arguments for and against a particular view, without perpetrating the error of committing oneself.
Many cases labelled convulsive tic might be quoted where the expression of so definite an opinion ought to have been reserved, as in one reported by Mayer[171] under the title of convulsive tic consecutive to infraorbital neuralgia:
A man, thirty-two years of age, had suffered from a severe infraorbital neuralgia of some weeks' duration, apparently attributable to a chill. The pains recurred at intervals till their substitution five years later for slight spasmodic twitches of the left eyelid, which gradually developed into violent convulsions of the whole of the left half of the face. These spasms were preceded by a sensation of numbness in the left ear, while during repose no modification of facial expression was to be remarked.
Further, there was a history of exactly similar neuralgia and spasm in the mother of the patient, although in her case the latter had been the first to appear, and had been replaced after a six years' interval by left facial neuralgia, which resection of the nerve failed to relieve.
In these cases the condition is undoubtedly one of painful facial spasm, inaccurately and unfortunately styled "tic douloureux."
Bruandet[172] has recorded a typical example of right facial hemispasm consequent on facial neuralgia, in which, however, no certain macroscopical or microscopical lesion was detected, in either cortex or bulb. But the mere fact that no structural alteration was discovered post-mortem cannot invalidate the diagnosis; the imperfection of our methods of investigation suffices to explain the negative results of such researches.
B. Tic or Spasm of the Neck—Torticollis Tic and Torticollis Spasm