PATHOLOGICAL ANATOMY
Our ignorance of the pathological anatomy of tic is profound. Hitherto
all the cases labelled tic in which a post-mortem examination has been
made have in reality been spasmodic affections differing essentially
from the tics as we understand them, according to the ideas of
Trousseau, Charcot, and Brissaud. As far as we are aware, not a single
sectio of a genuine case of tic is on record where a lesion, of whatever
nature or whatever site it be, has been discovered to which the tic
might be attributed. Either an autopsy is not obtained, or if it is, no
special abnormality is remarked, or else the diagnosis has been
erroneous and the changes described have not been those of tic.
It would be premature, of course, to conclude that tic is a disease
_sine materia_. The affirmation is quite unwarranted. As is the case
with numbers of neuroses and psychoses, we must for the present rest
satisfied to observe symptoms; the mystery of their morbid anatomy will
remain unsolved until our methods of investigation attain perfection.
Magnan[39] says of "superior degenerates" that clinical observation
reveals functional disorders so distinct and so invariable that it is
impossible they should not be the outcome of some pathological
modification of the organism. It is true he declares in another
place[40] that the mentally unstable have all a family likeness,
consisting not in identity of well-defined anatomical lesions, but in
similarity of functional derangements. As it is, from the motor point of
view tic is a functional act, and the governing centre is a functional
centre that has become hypertrophied, so to speak, by being educated to
excess. This physiological centre must not be confused with the "centre"
of current anatomical terminology; it does not exercise an exclusive
control over a particular territory--several such may co-exist in a
single anatomical area.
Our lack of knowledge concerning the precise localisation of these
functional centres is paralleled by our ignorance as to the manner of
their involvement.
Noir has prudently observed that the manifestation of co-ordinated tics
in cases of widespread cerebral disease, and the frequent occurrence of
the most extensive and complex varieties in patients who have suffered
from meningeal affections, suggest their cerebral origin. On these
points, however, anatomo-pathological information is to seek, and for
that matter the direct dependence of such an habitual movement as a
co-ordinated tic upon one lesion is scarcely within the bounds of
probability. Tic pertains to a psychical rather than to a motor sphere,
and is to be regarded as a disease of the will.
With this statement, and with the expression of our hope that subsequent
work will aid in the elucidation of the question, we shall close the
chapter of the tic's pathological anatomy. It may not prove superfluous,
however, to indicate why and how the facts gleaned from pathology and
supposed to be in harmony with the clinical picture of tic should be
allocated to other morbid entities.
In several cases considered to be tics of the face, cortical lesions
have been discovered at the posterior end of the second frontal
convolution, in the centre for voluntary and co-ordinated movements of
the contra-lateral facial muscles. It has become classical to cite an
example described as long ago as 1864 by Debrou[41] under the title
"painless facial tic," but a glance at the observation suffices at once
to negative its classification as a tic, and to justify the diagnosis of
a spasm of a quite peculiar sort.
On February 26, 1862, a porter, aged forty-nine, was suddenly
seized with an "attack of the nerves," and at its close lost his
speech. When examined at the hospital two days later, he was found
to have full use of his limbs, understood perfectly all that was
said to him, and evinced great impatience at being unable to
respond except in writing or by gesture. He made signs to indicate
that his head was paining him, and that he had difficulty in
swallowing. In addition, abrupt, forcible, and rapid movements of
the facial muscles on the right side were taking place; the angle
of the mouth and the outer angle of the palpebral aperture were
being dragged on; the external ear was elevated, or moving to and
fro; the platysma was twitching visibly and the hyoid bone so acted
on as to pull up the larynx spasmodically. The exhibition was an
exact replica of the effect produced in animals by intracranial
galvanisation of the facial nerve. Moments of absolute repose
alternated with periods of spasm of a few seconds' duration, which
addressing or handling the patient seemed to aggravate. There was
synchronous spasm in the masseter muscles, resulting in elevation
of the inferior maxilla. No other region of the body was affected.
On the night of March 2 the attacks of spasm and of pain increased
in intensity and frequency, without any other change in their
nature. The patient's mind remained unclouded, and as he was still
deprived of the faculty of speech, he again indicated in writing
the severity of his sufferings. About eleven o'clock at night the
situation became more distressing; he began to be profoundly
agitated, then passed into a more or less maniacal state, in which
his limbs were involved in powerful muscular spasms, his eyes
rolled in their sockets, and his respiration commenced to be
stertorous, while the violence of his struggles necessitated the
intervention of two assistants to control him. An hour or two
later, during one of these attacks the end came.
At the autopsy, under the arachnoid and spreading over the left
hemisphere at the junction of its anterior and middle thirds, was a
large blood-clot, dark, coagulated, and free in the cerebral
substance, which it had penetrated for a depth of about one
centimetre. It appeared to be of about four or six days' formation,
and probably dated from the incipient "attack of the nerves."
Painstaking scrutiny of the cerebellum and cranial nerves failed to
reveal any further pathological condition.
To tell the truth, we are not averse to wagering that to-day the opinion
of the surgeon would be invited on a similar case, where the motor
reactions of the so-called tic are manifestly based on a Jacksonian
type.
In a case recorded by Chipault and A. Chipault,[42] and characterised by
brief epileptiform attacks involving the left side of the face, cerebral
exploration proved ineffectual, but at the post-mortem a subcortical
glioma of the size of a cherry was discovered underneath the posterior
end of the second frontal convolution. Is a case of cerebral tumour to
be labelled _tic_?
It is quite exceptional, in fact, for lesions of the cortical facial
centres to give rise to muscular movements suggesting facial tic. Take
another instance:
An interesting case (says Brissaud), and one that is everywhere
quoted, is reported by Schultz, in which an aneurism of the
vertebral artery, at the point where the basilar arises, compressed
the trunk of the left facial nerve, and occasioned a "tic" of ten
years' duration. As a matter of fact, one could not have a better
example of _spasm_ pure and simple.
Féré[43] cites the following incident in support of the contention that
encephalic trauma may engender a tic:
A man in falling on his head sustained an injury to the cranial
vault over the posterior section of the left parietal bone, at a
spot exactly corresponding to the posterior part of the angular
gyrus, and immediately became afflicted with a convulsive tic of
the zygomatics and orbicularis palpebrarum on the right.
Conformably to Ferrier's experimental localisation of the motor
centre for the eye muscles and lids in the angular gyrus,
irritation of this centre by the cranial injury was the diagnosis
made.
The proffered interpretation of the motor phenomena by cortical
excitation is entirely justifiable, but no convulsion consecutive to
traumatism can ever pass muster as a tic.
A no less frequently quoted experiment of Gilbert, Cadiot, and
Roger,[44] supposed to confirm certain results obtained by Nothnagel, is
now a standard case in the history of tic hypotheses. The animal in
question was a dog affected with spasmodic twitches of the ear, which
the successive removal of cortical facial centre, internal capsule,
corpora striata, and cerebellum, signally failed to alleviate, and which
disappeared only with the destruction of the corresponding nucleus in
the pons. Their inability to find any anatomical change determined the
experimenters in favour of the view that the trouble was functional, and
they described it as a tic.
It would be foolhardy to deny the existence of a lesion on the ground
that it was not discovered. Negative findings of this sort are
valueless. The sole conclusion to draw from the incident is the
all-important rôle played by the bulbar centres in the production of
convulsive movements, which are in such circumstances, of course, nought
else than spasms.
Compression of cranial nerves by tumours or aneurisms of the base has
been the cause of symptoms imagined to be identical with those of tic.
The case of intracranial neoplasm mentioned by Oppenheim, in which
irritation of the upper branch of the trigeminal was accompanied by
homolateral facial contraction, is wholly comparable to the so-called
"tic douloureux."
No less positive is our refusal to accept as tics spasmodic
contractions in association with or subsequent to facial palsy or
contracture of peripheral or central origin. They are spasms, not tics.
Cruchet, for instance, describes indifferently as labial tic or
intermittent labial hemispasm clonic elevation or depression of the oral
aperture developing in central facial paralysis, especially in children.
As example he refers to the case of a child in whom an ictus at the age
of three years was followed by a typical spastic hemiplegia on the left
side, with athetoido-choreic movements chiefly in the arm.
At first the left side of the face was flaccid and deviated in the
other direction, but at the time of examination it presented no
unusual feature beyond a continual twitching, a real convulsive
tic, of the upper lip.
Now, whatever a facial convulsion of apoplectic origin, secondary to
facial palsy and accompanied with spastic hemiplegia and athetosis, may
be, it is at all events no tic.
Take one more case, given by Buss[45] as "convulsive tic of the left
side of the face."
The patient was an atheromatous subject, with cardiac hypertrophy,
bronchitis, and emphysema. When he first came under observation at
the hospital, his eyelids, cheek, and buccal commissure were the
seat of painless clonic contractions, which a month later were
complicated by giddiness, vomiting, inability to stand or walk,
lancinating pain over the right side of the face, weakness of the
right limbs, and left facial paresis, and had become fugitive and
insignificant. Loss of consciousness was followed by flaccidity of
all four extremities, hyperpyrexia, and death. The section showed a
hæmorrhage of the dimensions of a pigeon's egg which had destroyed
the left half of the pons, and an atheromatous dilatation of the
left posterior cerebellar artery, impinging at one spot on the
seventh and eighth nerves of the same side. Microscopical
examination of their trunks and of the facial area in the pons
disclosed no abnormality.
The pathological anatomy of this case indicates its nature unmistakably,
and its symptomatology and evolution, moreover, do not bear the
remotest resemblance to those of tic.
In the opinion of Debrou,[46] convulsive tic is a functional derangement
of a motor nerve, analogous to the neuralgia of a sensory one. To
strengthen his argument he relied on such cases as those of Romberg,
Schultz, Rosenthal, Oppolzer, where disease of neighbouring structures
(enlarged glands, otitis media, caries of the temporal bone, etc.) was
the agent in the production of muscular twitches in the domain of the
facial. In our view, however, they are simply spasms provoked by
irritation on the centrifugal path of a reflex bulbar arc.
The slight contractions occasionally seen both on the paralysed and on
the non-paralysed side in the secondary contracture stage of facial
palsy--a condition noted by Duchenne of Boulogne, Hitzig, and others,
and distinct from fibrillary twitching--are nothing more than spasms,
and the same obtains where the palsy is consecutive to affections of the
ear.
Chipault and le Fur recently[47] communicated to the Academy of Medicine
a case of intermittent attacks of acute pain in the right hypochondriac
region, associated with violent contractions of the muscles of the right
abdominal wall, which they described as a tic comparable to tic
douloureux of the face. It was seen at the subsequent operation that the
eighth, ninth, and tenth posterior spinal roots on the right side were
surrounded in their passage through the meninges by a patch of matted
and cicatricial arachnoiditis, dissection of which was instrumental in
effecting immediate relief.
One could not desire a more typical example of reflex spasm, the area of
irritation in this case being situated at a point on the centripetal arc
close to the medullary centre.
We may be allowed to quote a last case from Cruchet:
A little phthisical girl, four and a half years old, began to
complain of headache, and in the course of the next day became
delirious. Three days later the delirium gave place to generalised
convulsive seizures affecting chiefly the arms, and more pronounced
on the left side. Simultaneously a tic of the right side of the
face was observed, distinguished by raising of the upper lip and
closure of the palpebral aperture. Sleep brought no modification in
its train. Up to this stage a very feeble degree of contracture of
the jaw muscles had been noted, but this speedily became
accentuated to such an extent that nasal feeding had to be adopted.
Some hours previous to the child's death the tic disappeared, only
occasional slight convulsive twitches of the right arm remaining.
Consciousness was maintained to the last minute.
At the autopsy the characteristic appearances of tuberculous
meningitis were found: the base of the brain at the anterior
perforated spot and origin of the sylvian artery was covered with
gelatinous purulent patches, the colour of prune juice, which
extended backwards to the pons; one in particular had enveloped the
basilar trunk and sent out a prolongation on the right side, which
surrounded the sixth, seventh, and eighth nerves at their point of
emergence.
For our part, we cannot apply the word tic to the convulsive phenomena
of tuberculous meningitis. If localised spasms occurring in the course
of a grave illness, associated with fever, headache, and delirium, with
contractures and generalised convulsions, and if the spasmodic
manifestations of rapidly fatal pyrexias, are all to be denominated
tics, then the term has no longer any significance, and it would be
wiser to give it at once its quietus.
We are well enough aware that Cruchet believes there is a "convulsive
tic symptom"; in other words, certain symptoms in such and such a
disease appear in the guise of convulsive tic, "a movement or
combination of movements representing in a clonic fashion a
physiological act." Nevertheless, we are not convinced that the
convulsive movements of Cruchet's patients exhibit the sequence of
"regulated physiological acts."
He further draws an analogy between the foregoing case and the partial
convulsions of toxæmias, cerebral tumours, etc., "transient convulsions
supervening in the course of acute or chronic affections, and readily
recognisable." In exceptional circumstances they may "assume the form of
convulsive tic." In strict truth the _form_ may be the same, but
examination of the patient will soon demonstrate that the two are alike
merely in appearance, and compel the reconsideration of an immature
diagnosis.
Our position is that tic is more than a symptom--it is a
symptom-complex. Cruchet's definition of convulsive tic just quoted is
by itself insufficient; the additional and indispensable factor is the
characteristic mental defect, of which so illuminating an exposition was
given by Charcot.
* * * * *
Finally, the knowledge derived from the pathological investigation of
myoclonus and polyclonus does not of necessity throw light on the morbid
anatomy of tic.
In the case of an epileptic who suffered from myoclonus in his last
years, ischæmic degenerations were found by Rossi and Gonzales
disseminated throughout the brain, especially in the rolandic area, but
any inference to hold good for the tics would be premature.
The term polyclonus has been employed by Murri to designate a succession
of clonic contractions of the limbs, due to the existence of punctiform
hæmorrhages or areas of softening scattered throughout the rolandic
cortex. The character of the motor reaction in these cases, however,
bears no resemblance either to tic or to chorea, although the fact of
the relation between diffuse cortical lesions and convulsive movements
is calculated to enhance the difficulties of diagnosis.
Vincenzo Patella[48] has recently called attention to a case of
polyclonus in which the disappearance of the symptoms during sleep
suggested their purely functional origin, but histological examination
of the rolandic grey matter at a subsequent period revealed the presence
of numerous foci of degeneration. We are as yet, however, far from
grasping the real meaning of such symptoms, which, moreover, from the
clinical standpoint, cannot always be assimilated to those of the tics.
Conclusive anatomical information is therefore still being awaited.
The functional nature of the movements we have had under discussion is
unfortunately an obstacle in the way of our early knowledge of their
pathology. As long as we remain ignorant of the actual cause of the
neuroses and psychoses, so long will the pathological anatomy of tic
continue a sealed book. All that has been written on this topic hitherto
really concerns spasm and other convulsive affections secondary to
irritation of nerve centres or conductors. If we may venture to express
an opinion, it is that we should not be surprised if post-mortem
examination rest constantly negative. As a matter of fact, we do not
favour the view that the phenomena depend on an acquired lesion; rather
are we inclined to believe that they represent some congenital anomaly,
some arrest or defect in the development of cortical association paths
or subcortical anastomoses, minute teratological malformations that our
medical knowledge is still unhappily powerless to appreciate.