Tics and Their Treatment. Feindel Eugène

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СКАЧАТЬ 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, nibbling at the bit, etc. What else are these than persistent contractions or tonic tics, alternating or co-existing with jerking movements or clonic tics?

      We have no desire, of course, to over-estimate the argumentative value of this passage, the interest of which is mainly historical; but we find ourselves wholly in accord with Cruchet when he remarks of the scientific distinction formulated by Willis, and again by Michael Etmüller, between continuous, permanent tonic convulsions, and intermittent, momentary clonic convulsions, that it is uninvolved, practical, and of universal applicability.

      In 1768 certain tics were classified among the tonic convulsions by Boissier de Sauvages. Marshal Hall7 gave an account of various tonic facial convulsions to which Valleix refers as non-dolorous tics or idiopathic convulsions of the face. Coming nearer to our own times, we find the distinction of which we have been speaking again elaborated by Jaccoud,8 in 1870, and accepted also by Rosenthal.

      Doubtless physiologists and pathologists are not invariably at one as regards the proper characters of the two, and subdivisions into continuous tonic contractions as opposed to intermittent tonic contractions have been deemed necessary; but without burdening the subject with a plethora of detail, we think it simple, suggestive, and clinically satisfactory to uphold Willis's generalisations and to enlist their help in the exposition of the tics. Hence, unless under special circumstances, we consider recourse to the epithet "convulsive" superfluous, and we shall employ the word tic by itself, except when there may be occasion to indicate the form of muscular contraction. The gain in conciseness is not likely to be neutralised by any loss of precision.

      From our rapid survey of the vicissitudes through which the tic has passed, we may profitably gather one or two lessons.

      In so far as is compatible with its nature, the schematisation of tic is indispensable. The inevitable variability of the personal factor and the absence of a real breach of continuity between any two essentially differing morbid affections ought not to deter us from the attempt to project a line of demarcation between them. Natural science is pledged to the labour of differentiation. It is the glory of Charcot's alternately synthetic and analytic work to have demonstrated the value of this method in the sphere of neuropathology. At the same time, the wisdom of attaching only a provisional importance to any scheme and of welcoming possible modification is of course self-evident. Inexact and undiscriminating inference may be a stumbling-block in the path of progress and inimical to the cultivation of the faculty of observation. Further, inaccuracy of definition not only exaggerates the liability to misunderstanding, but has sometimes also the disadvantage of promoting an illusory belief in the possession of the truth.

      CHAPTER III

      THE PATHOGENY OF TIC

      TIC AND SPASM

      Our study of tic can be approached only after a preliminary understanding as to the meaning of two words too frequently confounded even in scientific literature —tic and spasm. Let us explain, then, once for all, exactly what we intend by the latter.

      Etymologically (σπασμὁς, σπἁω, I draw) the word signifies a twitch, but as it is unfortunately considered a synonym for convulsion, the two expressions are used indifferently in medical parlance, though the desirability of restricting the application of the former has more than once been indicated. Littré's definition – "an involuntary contraction of muscles, more particularly of those not under voluntary control" – may appear somewhat idle, as the contraction of muscles not under the influence of the will can scarcely be other than involuntary. His intention was, no doubt, to reserve spasm for convulsive phenomena in non-striped muscle fibres; but in this limited sense the term has not met with acceptance, and it remains equivalent to "involuntary muscular contraction," whatever that may mean. Thus interpreted, it is applicable to any and every involuntary muscular movement, physiological and pathological, to the inco-ordination of tabes, to chorea, athetosis, tremor, etc.

      Rather than imagine a new substantive to characterise certain of these muscle contractions, we may retain the word in a somewhat wider though equally precise sense, and follow the distinction drawn by Brissaud9 in 1893: "a spasm is the result of sudden transitory irritation of any point in a reflex arc; … it is a reflex act of purely spinal or bulbo-spinal origin."

      By definition, then, a spasm is the motor reaction consequent on stimulation of some point in a reflex spinal or bulbo-spinal arc. To differentiate between the reflex, which is physiological, and the spasm, which is pathological, we may add as a corollary: the irritation provocative of the spasm is itself of pathological origin, and no spasm can occur without it. The anatomo-pathological substratum of a spasm is, then, some focus of irritation on a spinal or bulbo-spinal reflex arc, which may be situated in peripheral end organ, in centripetal path, in medullary centre, or in centrifugal fibre. Whatever be its localisation, it will determine СКАЧАТЬ