The pathology of hysteria must be considered with reference to the explanation of the exact condition of the cerebro-spinal axis during the existence of certain special grave phenomena of hysteria, such as hemianæsthesia, hemiplegia, paraplegia, and contractures.
What is the probable state of the nerve-centres and tracts during these hysterical manifestations? If, for example, in a case of hysterical hemianæsthesia it is admitted that the brain of the other side of the body is somehow implicated, although temporarily, what is the probable condition of this half of the brain? Is the cerebral change vascular or is it dynamic? If vascular, is the state one of vaso-motor spasm or one of paresis, or are there alternating conditions of spasm and paresis? Are true congestions or anaæmias present? If the condition is dynamic, what is its nature? Is it molecular? and if molecular in what does it consist? Is it possible to say absolutely what the pathological condition is in a disorder in which autopsies are obtained only by accident, and even when obtained the probabilities are that with fleeting life depart the changes that are sought to be determined?
Two hypotheses, the vaso-motor and the dynamic, chiefly hold sway. The vaso-motor, attractive because of its apparent simplicity, has been well set forth by Walton,24 who contends that while it may not be competent to easily explain all hysterical symptoms, it will best explain some of the major manifestations of hysteria—for example, hemianæsthesia. Hemianæsthesia, he argues, may appear and disappear suddenly; it may be transferred from one side of the body to another in a few seconds; so blood-vessels can dilate as in a blush, or contract as in the pallor of fear, in an instant. In fainting the higher cerebral functions are suspended, presumably because of vaso-motor changes; therefore the sudden loss of function of one-half of the brain-centres, seen sometimes in hysterical hemiplegia and hemianæsthesia, may easily be imagined to be the result of an instantaneous and more or less complete contraction of cortical blood-vessels on that side. Neurotic patients have a peculiarly irritable vaso-motor nervous system. He records a case seen in consultation with H. W. Bradford. The patient had a right-sided hemianæsthesia, including the special senses, the sight in the left eye being almost wanting. The fundus of the right eye was normal; the left showed an extreme contractility of the retinal blood-vessels under ophthalmoscopic examination; these contracted to one-third their calibre, and the patient was unable to have the examination continued. The explanation offered is, that spasm of the blood-vessels on the surface of the left cerebral hemisphere had caused, by modification of the cortical cells, a right-sided hemianæsthesia, including the sight, and by reaching the meninges a left-sided spastic migraine, and by extending to the fundus of the left eye an intermittent retinal ischæmia.
24 Journal of Nervous and Mental Disease, vol. xi., July, 1884, p. 424 et seq.
The vaso-motor hypothesis is held by Rosenthal,25 who, however, wrongly gives the spinal cord the preponderating part in the production of the symptoms. According to this author, the anæsthesia and analgesia present in hysteria conform to the law as established by Voigt with regard to the distribution of the cutaneous nerves. The sensory nerves form at the periphery a sort of mosaic corresponding to an analogous arrangement in the spinal cord. “It is evident,” he says, “that the peripheral disorders in hysteria merely represent an exact reproduction of the central changes, and that the latter are situated, in great part, in the spinal cord.” He attributes a large part of the symptoms of hysteria to a congenital or acquired want of resistance of the vaso-motor nervous system. “Motor hysterical disorders are also due in the beginning to a simple functional hyperæmia, but in certain forms the chronic hyperæmia may lead to an inflammatory process which may terminate (as in Charcot's case) in secondary changes in the columns of the cord and nerve-roots.” When the brain is involved in hysteria, he holds that the most serious symptoms must be attributed to reflex spasms of the cerebral arteries and to the consequent cerebral anæmia.
25 “A Clinical Treatise on Diseases of the Nervous System,” by M. Rosenthal, Vienna, translated by L. Putzel, M.D., vol. ii. Wood's Library, New York, 1879.
The dynamic pathology of hysteria is probably believed in by most physicians, and yet it is difficult to explain. Thus, Briquet26 says that hysteria manifests itself by derangement of the nervous action, and what is called nervous influence is something like electricity. It is simply the result of undulations analogous to those which produce heat and light; in other words, it is a mode of movement. Wilks27 compares some of the conditions found in hysteria to a watch not going; it may be thought to be seriously damaged in its internal machinery, yet on looking into it there is found a perfect instrument that only needs winding up. As regards the brain being for a time functionless, the possibility of this is admitted by all, as in sleep or after concussion. He mentions the case of a young girl who had been assaulted, and had complete paralysis of motion and sensation. The shock had suspended for a time the operations of her brain, and organic life only remained. We have only to suppose that half of the brain is in this way affected to account for all the phenomena of hemianæsthesia.
26 Op. cit.
27 Lectures on Diseases of the Nervous System, delivered at Guy's Hospital, by Samuel Wilks, M.D., F. R. S., Philada., 1883.
According to the dynamic view, the central nervous system is at fault in some way which cannot be demonstrated to the eye or by any of our present instruments of research. The changes are supposed to be molecular or protoplasmic, rather than vaso-motor or vascular.