if by degeneration be meant a more or less pronounced hereditary psychopathic or neuropathic tendency which betrays itself by actual physical or psychical stigmata, then tic patients are unquestionably degenerates. If degeneration unveils itself in multifarious psychical or physical anomalies, the subjects of the tic are undoubtedly degenerates. If a degenerate may suffer from one or other variety of aboulia, or phobia, or obsession, the man with tic is a degenerate too.
Thus understood, the epithet may be applied to all individuals affected with tic. In fact, they must be degenerates, if the word is to be employed in its most comprehensive sense. But the explanation is insufficient, inasmuch as the converse does not hold good; all degenerates do not tic.
We may be safe in maintaining, then, that tic is only one of the manifold expressions of mental degeneration, but we are not much enlightened thereby. Obsessions and manias similarly are indications of mental deterioration, yet the fact conveys very scanty information as to their real nature. Physical anomalies – ectrodactyly, for instance – betoken physical degeneration, no doubt; but are inquiries to cease with this categorical assertion? Such certainly was not the idea of those observers whose is the praise for having demonstrated the common parentage of the heterogeneous manifestations of degeneration. Synthesis cannot exclude the work of analysis, and in practice there is scarcely a case to which this doctrine is not pertinent.
Every physical and every mental anomaly is the fruit of degeneration; every individual who is a departure from the normal is a degenerate, superior or inferior as the case may be. As instances of the latter we may specify the dwarf and the weak-willed; of the former, the giant and the exuberant. This sane and comprehensive conception of the subject must command universal acceptance as a synthetic dogma, but it cannot supplant the description and interpretation of individual facts. However legitimate be our representation of tic as a sign of degeneration, it is obviously inadequate if we rest content with styling its subject a degenerate.
Unfortunately the inclination too often is to be satisfied with the term, and to imagine that therewith discussion terminates. Still more unfortunately, in concentrating their attention on the mental aspect of the disease, some have altogether lost sight of one of its fundamental elements, viz. the motor reaction, and have conceived the possibility of its occurrence without any tic at all. Cruchet actually postulates the existence of an exclusively psychical tic, with no external manifestation.
To these questions, however, we shall return. The present introductory sketch is intended merely to demonstrate the ease with which ambiguity arises, and the desirability of its removal. We are fully conscious of the value of the work of Magnan and his school in emphasising a phase of the subject the exposition of which can only result in gain.
The investigation of the motor phenomena of tic is no less encircled with perplexities. Not only are the troubles of motility boundless in their diversity and correspondingly difficult to classify, but they also bear so close a resemblance to a whole series of muscular affections that one is tempted to describe a special symptomatology for each individual case.
For several years there has been, more especially outside of France, a manifest tendency to aggregate all convulsions of ill-determined type into one great class, under the name "myoclonus"; and into this chaotic farrago, it is to be feared, will tumble a crowd of conditions which should be studiously differentiated: the tics, electric and fibrillary choreas, paramyoclonus multiplex, etc., etc.
In the present state of our knowledge, according to Raymond,5 we must be guided by the lessons of clinical experience, which teach us, first, that the varying modalities of myoclonus develop from the parent stock of hereditary or acquired degeneration; and, secondly, that transitional forms which do not fall into any of the received categories are of common occurrence.
From a general point of view, the deductions are entirely reasonable. There is a suggestive analogy between these conditions and the muscular dystrophies in the persistence with which their multiplicity seems to defy the efforts of classification. The analytic stage witnessed the rapid evolution of such clinical types as the facial, the facio-scapulo-humeral, the juvenile, the pseudo-hypertrophic, not to mention others that bear the name of their observer; but it has been succeeded by the synthetic stage, whose function it is to incorporate all the former myopathies in the comprehensive group of "muscular dystrophy."
Yet here, again, peril lurks in too hasty a generalisation. To give the disease a name is not equivalent to pronouncing a diagnosis. The denominations "myoclonus," "muscular dystrophy," "degenerate," are alike inconvenient. Their scope is at once too inclusive and too exclusive. They may be indispensable; they are assuredly not sufficient.
The possibilities of misapprehension do not end here.
The manifestation of each and every tic – be it a flicker of the eyelid, a turn of the head, a cry, a cough – is through the medium of a muscular contraction. On the very nature of this contraction opinion is divided.
To its distinctive features of abruptness and momentariness is due the epithet "convulsive" habitually assigned it, but the qualification is not secure. Since the time of Willis the word convulsion has been employed in a double sense, to signify clonic muscular contractions (the "convulsion" of popular parlance) and tonic muscular contractions (a meaning attached to the term only by the scientist).
For our part, we can raise no valid objection to the specification of tics as convulsive, provided always that the existence of clonic convulsive tics and of tonic convulsive tics be recognised. As a matter of fact, clinical observation supplies instances of both sorts.
Nevertheless, attention has been confined by a majority of authors to the consideration of the former variety only, so much so that a whole order of facts which in derivation, essence, and external characteristics ought to be identified with the tics has been passed over in silence. Even on the assumption that the proposal to recognise the two classes cannot be entertained, at the least it is advisable to predetermine the import of the word convulsion, and to speak of clonic convulsive tics. This is the formula of Ferrand and Widal in their article "Convulsion" in the Encyclopædic Dictionary of the Medical Sciences. Similarly, Troisier6 says that the convulsive tic properly so called is characterised by clonic movements, in which opinion Erb and most German observers concur. Tonic tic appears to have been forgotten, and we have thought it our duty to resuscitate it.
Cruchet has quite recently approached the subject in a critical fashion:
To extend the term tic to tonic spasms such as mental torticollis, mental trismus, or permanent blepharospasm, is singularly to outstep the limits of its significance. We believe Erb, Troisier, and Oppenheim are warranted in restricting convulsive tic to clonic convulsions, and the consequent simplification and elucidation of the question lead us to adopt the same view.
If it be solely a matter of terminology, and if universal consent reserve tic for convulsions whose expression is clonic, we shall be the first to withdraw the phrase "tonic tic," making the single proviso that some other designation be found for a condition which differs from the clonic tic only in its external features, and not in origin, pathogeny, or treatment.
What is this other name to be? Are these tonic muscular contractions to be regarded as synonymous with contractures? If so, do we mean myotetanic contracture – to utilise the excellent division imagined by Pitres – as in hysteria, or myotonic contracture, as in Parkinson's disease? The state of muscular contraction in tonic tic does not correspond accurately to either, though it is certainly more akin to the myotonic form; but myotonia is a sort of caput mortuum for the too facile classification of cases in reality difficult to place, and we are afraid the term is not calculated to ensure precision of ideas.
Should we be reproached with straining the primary meaning of the word tic by applying it to a contraction of a certain duration, we find ample justification ready at hand in the pages of Cruchet himself. "It was probably in 1656," he says, "that tique appeared in the French language, in the works of Jean Jourdin." Now, in the quaint description of the horse's tique given by that writer, the signs of the disease are said to be cocking of the ears, rolling of the eyes, clenching and gnashing of the jaws, stiffening of the tail,