Chapter LXXVII: Introduction: This disease remained unnoticed until twenty years ago, (1)

when Brown-Séquard, observing that certain lesions of the spinal cord were accompanied by symptoms resembling those which he witnessed in animals after section of one lateral half of the cord, recognized it as a special affection. Although some of the accompanying phenomena of such a section had likewise been observed by Stilling, Budge, Eigenbrodt, Tuerk, Schiff, Von Bezold, and Van Kempen,[1] nevertheless this whole group of symptoms, as belonging to the same disease, was first clearly recognized and anatomically demonstrated by Brown-Séquard.[2] According to this physiologist, a section or a destruction of a small portion of a lateral half of the spinal cord in its cervical region gives rise to the following phenomena: namely, on the injured side is observed a paralysis of voluntary motion, of the muscular sense, and of the blood-vessels; the latter, manifesting itself by a greater supply of blood and a higher temperature of the parts, may continue to exist for some years. There is, furthermore, an increased sensibility of the trunk and extremity to touch, prick, heat, cold, electricity, etc., owing to vaso-motor paralysis, though in some cases a slight anæsthesia may exist in a limited zone above the hyperæsthetic part, and also in certain parts of the arm, breast, and neck. Besides these symptoms, vaso-motor paralysis of the corresponding side of the face and of the eye, manifested by an elevated temperature and sensibility, partial closure of the eyelid, contracted pupil, slight contraction of some of the muscles of the face, etc., may also be present. On the opposite side of the injury an anæsthesia of all kinds of sensation, excepting the muscular sense, is observed in both extremities; there is also an absence of motor paralysis. The anæsthesia on this side is owing to the decussation of the sensory nerves in the spinal cord.

[Footnote 1: Eckhard, “Physiologie des Nervensystems,” in _Handbuch der Physiologie_, edited by L. Hermann, 2d part of vol. ii. p. 165.]

[Footnote 2: “On Spinal Hemiplegia,” _Lancet_, Nov. 7, 21, and Dec. 12, 26, 1868, reported in _Virchow and Hirsch's Jahresbericht_ for the year 1868, vol. ii. p. 37.]

If the hemisection of the cord is made in the dorsal region, the functional disturbances are limited to that part of the body below the point {1166} of division, and a hemiparaplegia, or paralysis of the corresponding lower extremity, will be the result.

From these facts it will be readily understood that a lesion occurring in any portion of one lateral half of the spinal cord of man must be followed by some or all of the above-mentioned symptoms, and that the phenomena produced by physiological experiments on animals constitute, in reality, the pathological basis of unilateral spinal paralysis in man. They will be more clearly understood by calling to mind the course of the musculo-motor, vaso-motor, and sensitive tracts in the spinal cord. Thus, the musculo-motor tracts, after having descended to the crura cerebri, cross one another in the pyramids of the medulla oblongata and adjoining upper portion of the spinal cord, forming the so-called decussation of the pyramids; they then descend through the spinal cord to supply the muscles of the same side of the body.[3] A section of one lateral half of the cord therefore causes motor paralysis on the same side. The vaso-motor tracts remain uncrossed, and pass, each, through one lateral half of the cord to supply the vessels on the same side; some regions of the body are stated to make an exception to this rule. According to Brown-Séquard, the sensitive tracts conducting the different kinds of sensation, with the exception of the muscular sense, on the contrary, cross over to the opposite half of the spinal cord soon after their entrance into it, and thence pursue their further course to the brain. A section of one lateral half of the cord, therefore, will be followed by a loss of sensation of touch, pain, heat, tickling, etc. on the other side of the body.

[Footnote 3: Though, in the majority of cases, a complete decussation of the motor tracts probably takes place in the pyramids, the researches of Flechsig have shown (_Die Leitungsbahnen im Gehirn und Rückenmark des Menschen_, p. 273) that there are a number of others in which the decussation is not complete, but where a part of these tracts passes to the spinal marrow uncrossed on the inner surface of the anterior white columns.]

The symptoms above mentioned must of course vary according to the extent, the intensity, and the particular nature of the lesion, as well as the height at which it is located in the spinal cord.

DEFINITION.—The chief characters of unilateral spinal disease are motor paralysis, hemiplegia, or hemiparaplegia, paralysis of the muscular sense and of the blood-vessels on the side of the lesion, and paralysis of sensation with preservation of the muscular sense on the other side of the body. These symptoms may vary, and be accompanied by other phenomena according to the particular seat, extent, and depth of the lesion.

SYMPTOMS.—According to the nature of the lesion, the symptoms of unilateral disease of the spinal cord may be developed suddenly, as, for instance, when caused by traumatic injuries; or in a gradual and slow manner, when they may be preceded by premonitory symptoms, such as vertigo, pain on the side of the lesion, etc. The most prominent clinical phenomena, as before mentioned, are motor paralysis on the side of the lesion, and anæsthesia on the opposite side of the body. The motor paralysis on the side of the lesion may, according to the seat of the latter, manifest itself in either the form of a hemiplegia or hemiparaplegia, and even extend in a light form to the opposite side of the body. In typical cases, however, in which the injury or disease is strictly confined to one lateral half of the cord, the motor power on the other side {1167} of the body remains entirely undisturbed. At the same time, the muscular sense on the injured side is paralyzed or considerably diminished, and in some cases (Fieber, Lanzoni, Allessandrini) the electro-muscular excitability also has been found lowered, while in others it has remained normal. There is furthermore observed, on the side of the lesion, a vaso-motor paralysis, manifesting itself by a greater supply of blood to, and a higher temperature of, the paralyzed trunk and limbs, giving rise to an increase of sensibility (hyperæsthesia) of touch, prick, heat, cold, electricity, etc. in these parts. If the seat of the lesion is sufficiently high up in the cord, this paralysis extends, moreover, to the corresponding side of the face and eye, where it also causes an elevation of temperature, increase of sensibility, partial closure of the eyelid, contracted pupil, slight contraction of some of the muscles of the face, etc. In a number of cases at the boundary of the hyperæsthetic region a narrow anæsthetic zone is observed to exist on the breast, neck, or arm. This anæsthesia is owing to the division, at the level of the section, of some nerves of sensation on their way to the other half of the spinal cord. An increase of the reflex irritability of the tendons has in some cases (Erb, Schulz, Revillons) been observed, while in one case (Glaeser) the reflex was found to be absent. Swelling and œdema of the paralyzed limbs have also been met with (Glaeser), and in one case (Allessandrini) even swelling and pain in all the joints of the injured side were observed before death, while masses of coagulated blood in these joints, particularly in the knee, were revealed by the autopsy. The inflammatory affection of the knee-joint of the paralyzed leg has, moreover, been observed by Viguès, Joffroy, and Solomon.[4] Frequently, atrophy of the paralyzed muscles takes place, especially in chronic cases. In one case (Fieber) even atrophy of the upper extremity of the uninjured side of the body was observed.

[Footnote 4: Erb, “Diseases of the Spinal Cord, etc.,” _Cyclopædia of the Practice of Medicine_, edited by H. v. Ziemssen, Amer. ed.]

The most prominent symptoms observed on the side of the body opposite to the seat of the lesion are anæsthesia of every kind of sensation, preservation of the muscular sense, and absence of motor paralysis. Reflex action and electro-muscular contractility generally remain normal, though in one case (Fieber) the latter was found increased. Although the anæsthesia of the skin generally comprises every kind of sensation, three cases were observed (Fieber) in which the sensation of heat remained unimpaired, while the electro-cutaneous sensibility appeared to be lost. As a general rule, there is no vaso-motor paralysis on the uninjured side, though in some cases (Erb, Allessandrini) an elevation of temperature has been observed.

Besides the above symptoms, some others, less characteristic in nature, are now and then observed in individual cases. They are painful sensations on one or the other side, or even simultaneously on both sides of the body, and also a feeling of constriction at the level of the lesion (Erb). Disturbances of the functions of the bowels or bladder are also met with, though in other cases they are absent.

PATHOLOGICAL ANATOMY.—The pathological changes taking place in the spinal cord of patients affected with unilateral spinal paralysis must vary in different cases according to the particular nature of the lesion giving rise to the characteristic symptoms. In those cases reported to {1168} have terminated by a gradual disappearance of the symptoms with or without therapeutic interference it is very probable that the exciting cause was a hyperæmia or a myelitis of a small portion of one lateral half of the spinal cord, sufficiently high in degree to impair the conducting power of the nerve-fibres passing through it. In some cases the myelitis may lead to a degeneration of the nerve-fibres, or even extend to the other half of the cord, and by calling forth additional symptoms render the case more complicated. In syphilitic cases the disease depends upon syphilitic deposits or neoplasms in the affected portion of the spinal cord; these cases, however, generally yield to treatment. In the same manner may circumscribed sclerosis give rise to the disease. Another cause may be found in the compression of the cord caused by meningeal tumors or by the fractured portions of some of the vertebræ. Chronic disease of the vertebral bones themselves (Pott's disease) may also, by encroaching upon the spinal cord, become an exciting cause.

The most typical cases, however, are those depending upon traumatic injuries, by which one lateral half of the spinal cord is forcibly divided. These lesions resemble in nature the division of the cord in the physiological experiments on animals, and are most frequently caused by a stab from a knife penetrating to the cord through the intervertebral spaces.

DIAGNOSIS.—In those cases in which the symptoms of unilateral spinal paralysis appear soon after an external injury to the spine, it becomes obvious that the latter is the exciting cause. In cases of a more chronic character, in which the symptoms appear gradually, the nature of the exciting cause can only be correctly determined by the observation of certain collateral symptoms characteristic of such causes as might give rise to the symptoms of the disease in question. As regards the diagnostic symptoms of unilateral spinal paralysis themselves, they are sufficiently characteristic to be easily distinguished from those of other forms of hemiplegia or hemiparaplegia. Thus, cerebral hemiplegia may be distinguished from the disease under discussion by the sensory disturbances being either absent or on the same side as the paralysis; furthermore, by the one-sided paralysis of the face and of the tongue and by the affection of various cranial nerves. The hemiplegic form of spasmodic spinal paralysis is distinguished by the absence of sensory disturbance, etc. Lastly, hemiplegia depending upon lesion of one side of the cauda equina is distinguished from unilateral spinal disease by the paralysis and anæsthesia being confined to the same side, and by generally affecting certain nervous districts of the lower extremities.

PROGNOSIS.—In unilateral spinal lesions the prognosis depends obviously on the particular nature and intensity of the exciting cause. On the whole, there are quite a number of cases reported, even of traumatic origin, which have terminated favorably.

TREATMENT.—The treatment of unilateral spinal paralysis depends, like the prognosis, upon the nature of the exciting cause. The principles upon which it is to be pursued of course are the same as those upon which the treatment of the various lesions causing the disease—such as hyperæmia, myelitis, sclerosis, wound of the spinal cord, etc.—is based.

{1169}

PROGRESSIVE LABIO-GLOSSO-LARYNGEAL PARALYSIS.

BY H. D. SCHMIDT, M.D.

SYNONYMS.—Chronic progressive bulbar paralysis; Progressive muscular paralysis of the tongue, soft palate, and lips.

HISTORY.—Although the particular group of symptoms constituting this disease must have been met with and known to the older medical observers, they were nevertheless first recognized as a special variety of paralysis in 1841 by Trousseau,[1] who named the affection labio-glosso-laryngeal paralysis. But as the memorandum prepared by this distinguished physician at the time when, in consultation with a medical colleague, he had observed the particular symptoms of this affection, unfortunately remained unpublished, twenty years more elapsed before the first accurate and detailed description of the symptoms and progressive nature of this disease under the name of progressive muscular paralysis of the tongue, soft palate, and lips was rendered by Duchenne. The writings of this author directed at once the attention of other medical men to this disease, and since that time a large number of cases have been reported and discussed,[2] while the microscopical examination accompanying the autopsies of many of them finally revealed that the seat of the lesion giving rise to the phenomena of this disease was to be sought in the nervous nuclei of the medulla oblongata. Hence at the present time the pathology of this disease is thoroughly understood.

[Footnote 1: _Clinique médicale de l'Hôtel Dieu de Paris_, vol. ii. p. 334.]

[Footnote 2: A very considerable number of cases of this disease, and discussions thereon, will be found reported in _Virchow and Hirsch's Jahresbericht über die Leistungen und Fortschritte der Gesammten Medizin_, for the years 1866-80, vol. ii., section “Krankheiten des Nervensystems.”]

DEFINITION.—That form of labio-glosso-laryngeal paralysis to be treated in the following pages is characterized by a progressive paralysis and atrophy of the muscles of the tongue, lips, palate, pharynx, and larynx, interfering in a greater or lesser degree with the articulation of words and sounds and with the functions of mastication and deglutition—affecting, furthermore, in the later stages of the disease, the voice and the function of respiration. The paralysis is caused by a progressive degeneration and atrophy of the ganglion-cells of those nerve-centres in the medulla oblongata from which the muscles of the above-named organs receive their supply of nervous energy, though in most cases the pathological process extends to, or even beyond, the roots of those nerves {1170} which originate in these centres and terminate in the respective muscles. In many cases the pathological process extends to the spinal marrow, and there causes paralysis and atrophy of the muscles of the trunk, and, generally, of the upper extremities. Almost in every case the disease, as its name indicates, slowly progresses until it terminates in death.

There are, however, a number of cases observed which, though exhibiting the same or similar symptoms, do not, in reality, depend upon a progressive degeneration and atrophy of the centres and nerve-roots of the medulla, but, on the contrary, owe their symptoms to other causes; as, for instance, to tumors, hemorrhages, syphilitic neoplasms, etc., which, either by pressing upon the medulla from without, or, if situated within, by deranging in various manners the individual nervous elements of that part, may give rise to some or even all of the symptoms of true labio-glosso-laryngeal paralysis. These symptoms, however, according to the character of the lesion, may, after remaining stationary for some time, retrograde, and even disappear, as has been observed in syphilitic cases; or they may progress, and finally end in death. In order to distinguish these cases from the chronic or progressive bulbar paralysis some authors have attached the term retrogressive to this form of the disease.

SYMPTOMS.—As the degeneration of the nerve-centres in the medulla oblongata, upon which the disease depends, does not proceed in a regular fixed order, the order in which the clinical symptoms successively appear also varies in different cases. In the majority of cases, however, the symptoms appear gradually, manifesting themselves generally in the form of a greater or lesser impediment in the articulation of certain sounds or letters depending upon the movements of the tongue, such as _e_, _i_, _k_, _l_, _s_, and _c_, while at the same time a difficulty of mastication and deglutition may be experienced by the patient, due to the progressive development of the paralysis, which deprives the tongue of its lateral and forward movements. To this cause also, at this period, the apparently increased secretion of saliva, running from the corners of the mouth, must be attributed. With intelligent patients these symptoms are rendered less prominent by the special effort which they make to pronounce slowly for the purpose of hiding the deficiency in their speech. But as the disease advances the difficulty of articulation increases on account of the paralysis extending to the orbicularis oris, thus affecting the mobility of the lips and interfering with the pronunciation of the labial sounds _p_, _b_, _f_, _m_, and _w_. With the loss of power of articulation the patient's speech becomes gradually reduced to monosyllables, or even, finally, to incomprehensible and inarticulated grunts, by which he expresses his wants to his friends. In consequence of the paralysis of the lips the patient becomes unable to whistle or blow or to perform any movement depending upon these organs, while at the same time, through the disturbance created in the co-ordination of the facial muscles by the paralysis of the orbicularis oris, the mouth becomes transversely elongated and drawn downward by the action of the remaining unparalyzed muscles upon its angles. With the mouth partially open and the lower lip hanging down, the face of the patient has a peculiar sad and painful expression, while the voice assumes a nasal sound on account of the paralysis of the palate.

After a while the difficulty of deglutition, caused by the inability of the {1171} tongue to properly assist in the formation of the bolus of food and its propulsion into the pharynx, increases on account of the paralysis extending to the muscles of the pharynx. The failure of these muscles in the performance of their special function of grasping the food and carrying it to the œsophagus obliges the patient to push it down the pharynx with his fingers. In some cases the difficulty of swallowing rests with solids, in others with fluids. The defective deglutition furthermore gives rise to spells of coughing and suffocation by portions of food getting between the epiglottis and larynx, while the paralyzed muscles of the palate allow the fluids to pass through the nose and enter the posterior nares.

As the case slowly proceeds the symptoms grow worse. The paralysis of the orbicularis oris reaches a point when this muscle is no more able to close the oral cavity; the mouth of the patient therefore remains open. The tongue, having now entirely lost its lateral, forward, or upward movements, rests motionless upon the floor of the mouth, evincing no other signs of life but occasional slight muscular twitchings. In some cases a diminution of the sense of taste, and also of that of touch in the tongue, pharynx, and larynx, has been observed. Atrophy of the tongue and lips now sets in, and the function of speech is almost entirely lost. The only letter which the patient is still able to pronounce is _a_ (broad); all other sounds are indistinct and can hardly be understood. The paralysis of the tongue and other muscles of deglutition gives rise, furthermore, to an accumulation of the now excessively secreted saliva, which, being retained in the oral cavity, assumes the form of a viscid mucous liquid dripping from the mouth, extending, in the form of strings or ribbons, between the surfaces of the lips. Finally, when, through the progressive paralysis of the orbicularis oris, the patient can no more close the lips, the flow of saliva from the mouth becomes continuous; he is then seen engaged in the constant use of his handkerchief for removing the secretion.

In the latter stages of the disease the pathological process extends to the centres of respiration, paralyzing not only the muscles of respiration, but diminishing at the same time the contractile power of the lungs. A great difficulty of breathing—consisting not only in the want of depth of the inspirations, but, moreover, in a feebleness of expiration (manifested by weak, powerless coughing)—then ensues, and the patient is no further able to blow his nose or clear his bronchial tubes from the accumulating mucus. The paralysis of the muscles of the larynx, also occurring at this stage, not only increases the difficulties of deglutition, but most seriously affects the voice of the patient by decreasing the innervation of the vocal cords; the voice then becomes hoarse and weak, to be finally entirely lost.

The decrease in the innervation of the heart—which, lastly, also occurs—gives rise to irregularities in the action of this organ, followed by irregularity of the pulse, attacks of syncope, feelings of extreme weakness, and fears of death; whilst simultaneously the insufficient performance of the respiratory function renders the breathing of the patient weaker and weaker. Feelings of great oppression in the chest then arise, and the patient may die during one of the now frequent attacks of dyspnœa and suffocation.

No fever or pain is observed during the course of this disease; sensation {1172} remains unaffected and the mind is perfectly clear. It is owing to these circumstances that frequently the patient walks about and attends to the duties of life, until shortly before death he becomes confined to bed by the great weakness caused by the want of nutrition. The appetite also remains good, but, unfortunately, in consequence of the difficulties attending the act of deglutition, the patient cannot satisfy the demands of his stomach. In the latter stages of the disease, therefore, when feeding can only be accomplished by the aid of the stomach-tube, every attempt to relieve the terrible gnawings and pains of hunger ends in a failure. With starvation staring in his face, the unhappy victim of the disease finally sinks into a state of extreme inanition, which, if life is not suddenly extinguished by an attack of suffocation, slowly leads to final dissolution.

The symptoms above described are those generally observed in uncomplicated cases of labio-glosso-laryngeal paralysis. There are, however, a number of cases reported in which the degenerative process has passed from the medulla oblongata to the spinal cord, and given rise to paralysis of the muscles of the neck, especially of the trapezius, and to those of the shoulders, and even to those of the upper extremities. Atrophy of the interosseus muscles of the hand, with those of the ball of the thumb, is not unfrequently observed. In other cases the disease has been found associated with progressive muscular atrophy, and in others, again, with paralysis of the lower extremities, accompanied by contractures and depending upon amyotrophic lateral sclerosis.

Labio-glosso-laryngeal paralysis is, as before mentioned, slow but progressive in its course, the duration of which is from one to three, or even five, years. It always terminates in death within the limits of this time, either from suffocation, inanition, paralysis of the heart, or some other intercurrent disease.

PATHOLOGICAL ANATOMY.—The macroscopical and microscopical examinations made during the last fifteen years of the cerebro-spinal axis in quite a number of cases of progressive labio-glosso-laryngeal paralysis show that this disease depends upon a degeneration of the nervous elements of the nuclei or nerve-centres in the medulla oblongata, involving also the roots of the nerves arising from the latter, and supplying with nervous energy the muscles of the different organs paralyzed in this disease. The exact nature of this degeneration—that is, whether it represents the sequel of a previously existing myelitis or originates in a so-called parenchymatous inflammation—appears to be as yet not definitely settled, though a number of pathologists entertain the view that it is preceded by a chronic myelitis. This view appears to be corroborated by the fact that frequently portions of the medulla oblongata and cervical portion of the spinal cord are found in a state of sclerosis. The uncertainty in the determination of the exact nature of the pathological process here concerned chiefly depends upon the diverse conditions in which the blood-vessels of the medulla are found. For while, in some cases, perhaps the majority, they have been found empty and in a normal condition, they have in others been met with congested with blood—a condition pointing to a chronic inflammatory process. In other cases, again, their walls have been found thickened or undergoing fatty degeneration.

At any rate, whether inflammatory or not, the now numerous microscopical examinations have revealed that the main features of the {1173} process are a degeneration and atrophy, not only of the ganglion-cells of the respective nervous nuclei with their plexuses, but also of the fibres of the roots of the peripheral nerves arising from these centres; frequently the degeneration extends to some distance upon the nerves themselves. The microscopical changes in the ganglion-cells consist of an increase of yellow pigment, a gradual disappearance of their nuclei, terminating in an atrophy of the ganglionic bodies themselves, the pathological process leaving, finally, nothing but irregularly-shaped masses of pigment in the places of these bodies. The degeneration of the nerve-fibres appears to consist, as elsewhere, in a swelling of the axis-cylinder, accompanied by atrophy of the medullary sheath—a condition which finally leads to the complete destruction of these elements of the nerve-fibres, so that, at last, the whole nerve is only represented by the connective tissue of its neurolemma. Besides these changes, certain pathological products, such as conglomerations of fatty granules or globules, amylaceous bodies, etc., are also found in the degenerated nerve-centres and nerve-fibres.

Although in different cases the route which the degenerative process pursues is not the same, a certain general order, in which the nerves and nerve-centres are successively affected, and corresponding to the clinical symptoms, appears, nevertheless, to exist. It is thus that the nucleus of the hypoglossus has been observed to degenerate before the other nerve-centres. The nuclei of the spinal accessory and pneumogastric nerves, and also that part of the facial nucleus from which the inferior division of the facial nerve arises, appear to be affected next. The glosso-pharyngeal nucleus appears not to be affected in all cases, and still less frequently the nuclei and roots of the abducens, auditory, and trifacial nerves. The fibres forming the anterior pyramids have frequently been found degenerated throughout the medulla oblongata and pons; sclerosis also has been met with in this locality. In many cases, as has been remarked before, the pathological process descends into the spinal cord. Here, as in the medulla oblongata, the degeneration is principally confined to the motor centres located in the anterior horns, while the posterior horns, together with the lateral and posterior white columns, remain free from disease. The degree of degeneration taking place in the fibres of the respectively paralyzed muscles also corresponds to that of the elements of the nerve-centres from which they are supplied. The microscopical changes observed in the muscular fibres consist in a decrease of their diameter, accompanied by an increase in the number of their nuclei, as well as in the quantity of the connective tissue surrounding the primary bundles; some authors have observed amyloid degeneration of the muscular fibres.

ETIOLOGY.—The causes which give rise to the pathological process above described are but little known. Nevertheless, in a number of cases the disease has been traced back to taking cold, to physical as well as cerebral over-exertion, mental excitement, sorrow caused by misfortunes, poverty of nutrition, excessive use of tobacco, etc. In some cases the disease commences in the spinal cord in the form of progressive muscular atrophy or amyotrophic lateral sclerosis, and gradually extends to the medulla oblongata; in many other cases no particular cause can be found. The disease is rarely if ever met with in persons under twenty years of age, but is confined to adult life and old age. It occurs in {1174} both high and low walks of life, attacking more frequently men than women.

DIAGNOSIS.—The symptoms of progressive labio-glosso-laryngeal paralysis are so characteristic in themselves as to exclude any mistake in the formation of a diagnosis. There are, nevertheless, some pathological conditions, such as hemorrhages in the medulla oblongata or thrombosis and embolism of the arteries supplying the latter with blood, which may give rise to the same or very similar phenomena, and thus render a correct diagnosis difficult. In such cases it must be remembered that the cause of true labio-glosso-laryngeal paralysis, depending upon degeneration and atrophy of the nervous nuclei along the floor of the fourth ventricle, is very gradual, while the symptoms produced by the causes before mentioned generally make their appearance in a more acute and sudden manner. The latter also, if not remaining stationary for some time, have rather a tendency to improvement, wanting, therefore, the progressive character of the former.

Tumors at the base of the brain also, by pressing upon the roots of the cerebral nerves or upon the medulla oblongata itself, may produce similar symptoms, which, on account of their comparatively slow and gradual development, may prove more difficult to distinguish from those characterizing genuine, progressive labio-glosso-laryngeal paralysis. Errors of diagnosis, however, may here be avoided by taking into consideration the special symptoms which generally accompany the presence of tumors of the brain, such as vertigo, headache, vomiting or even hemiplegia, and local paralysis. The sensory nerves also may become affected by the pressure of the tumor upon them. Thus, pressure upon the trifacial nerve may give rise to neuralgic pains, feelings of tingling and numbness, or even anæsthesia; while pressure upon the optic nerves or their tracts, or upon the olfactory and lingual nerves, will be followed by derangements of vision, smell, and taste. The symptoms produced by the pressure of a tumor at the base of the brain, moreover, are not strictly progressive, but may for some time appear, and disappear again before becoming permanent.

Facial diplegia, in which the expression of the face somewhat resembles that of a patient affected with labio-glosso-laryngeal paralysis, is distinguished from the latter disease by the paralysis affecting both divisions of the facial nerve, while the tongue remains free and deglutition is undisturbed.

There are still other affections of the cerebro-spinal axis, such as paralysis of the insane, disseminated sclerosis, etc., which in their course present some or perhaps all of the symptoms characterizing labio-glosso-laryngeal paralysis; these may be distinguished from the latter disease by taking their own special symptoms into consideration.

TREATMENT.—Although almost all cases of progressive labio-glosso-laryngeal paralysis terminate fatally, some cases have been reported by several observers in which a temporary improvement in the symptoms of the disease, or even a total cure, had been obtained by treatment. Of course such favorable results can only be obtained in the initial or earlier stages of the disease. Thus, Kussmaul recommends in the initial stage, when pains in the head and neck are present, wet cupping of the nape of the neck in strong persons, also the use of the shower-bath, while {1175} nitrate of silver may be given internally. The application of galvanism in an alternate direction he also recommends—first, through the neck, and later on through the whole spinal column—and at the same time currents in an alternating direction from the neck and hypoglossus nerve to the tongue. Dowse reported a case of bulbar paralysis which he cured by the application of the constant current upon the paralyzed parts, subcutaneous injections of atropine and strychnine, with the internal administration of cod-liver oil, quinine, and phosphorus. He attaches great importance to the careful feeding of the patient through a tube passed through the nose, and to the strict application of the galvanic current; for excessive salivation he recommends atropine. Erb recommends to regulate the diet and the habits of life of the patient in such a manner as to avoid every irritation of the nervous system; furthermore, to generally stimulate the nutrition in order to produce a tonic effect upon the nervous system. For this purpose he principally relies upon a cautious hydropathic treatment, to be continued for a long time and with great regularity. The greatest importance, however, he attaches to electricity, considering the best method of galvanism as follows: “Galvanize with stabile application transversely through the mastoid processes and longitudinally through the skull, the so-called galvanism of the cervical sympathetic (anode on the nuchus, and cathode at the angle of the lower jaw), and then induce movements of deglutition (twelve to twenty at each sitting); besides this, apply, according to circumstances, direct galvanic or faradic currents to the tongue, lips, and palate.” The electric treatment must be continued for some time, with from four to seven sittings a week. Of the medicines taken internally, Erb recommends nitrate of silver, iodide of potassium, iodide of iron, chloride of gold and sodium, ergotin, belladonna, and preparation of iron and quinine.

{1176} {1177}

DISEASES OF THE PERIPHERAL NERVES.

BY FRANCIS T. MILES, M.D.

The nervous system of the higher animals is the apparatus by which stimuli coming from the external world or originating in the interior of their own bodies are perceived (its sensitive functions), or cause muscular contraction (its motor functions), or, lastly, cause molecular changes in tissues (its trophic functions).

Besides this power which the nervous system possesses of receiving impressions originating outside of itself and actively replying to them, it appears also to possess the power of originating within itself changes the result of which are sensations, movements, and trophic alterations. In other words, it can act automatically.

The apparatus for the performance of these various functions consists of the end-organs, the nervous centres, and the nerves.

The end-organs are peripheral mechanisms for the reception of impressions. The structure and mode of action of some of them, as the eye and the ear, are pretty well understood, while others, as those connected with the sense of touch, temperature, etc., are but imperfectly known. It is probable that there are also peripheral mechanisms which facilitate the delivery of the impulses coming from the nerve-centres to the organs, tissues, muscles, glands, etc.

The nervous centres are made up of nerve-cells variously connected with each other. They are immediately concerned in receiving impressions conveyed to them by the nerves and transforming them into sensations, or transmitting them to other organs, causing reflex actions, or in originating sensations and impulses.

The nerves are organs which, connected at one extremity with the end-organs and at the other with the nervous centres, convey peripheral impressions to the centres, and impulses and influences from the centres to the various organs of the body.

As it is with diseases of the peripheral nerves that we are now concerned, let us begin by looking more closely into their structure and functions.

The nerves appear to the naked eye as white strands of variable size, which a close inspection shows to be made up of threads or fibrils (best seen when the cut end of a nerve is examined) bound together by fine connective tissue and scantily supplied with blood-vessels. A microscopic examination shows that each of the fibrils visible to the naked eye is made up of a great number of fibres. These are the medullated {1178} nerve-fibres, and they extend unbroken between the nerve-centres, with the cells of which they are connected, to the various organs and tissues, with which they also enter into organic union.

If we examine the structure of a medullated nerve-fibre, we find it to consist of a central thread called the central axis or axis-cylinder, in which close microscopic investigation shows a longitudinal striation, indicating that it is made up of fibrillæ. Surrounding the central axis like a sheath is the white substance of Schwann, composed of an oleo-albuminous substance, myeline, to which the nerves owe their white appearance. According to some observers, the white substance of Schwann is pervaded by a meshwork of fibres. Surrounding the white substance of Schwann is the sheath of Schwann, a structureless membrane having at intervals upon its inner surface nuclei, around which is a small amount of protoplasm.

At intervals along the course of the nerve-fibres are seen constrictions which involve the sheath and white substance of Schwann, but which do not affect the central axis, which passes unbroken the points of constriction. These are the nodes of Ranvier. Each space on the fibre beneath the nodes of Ranvier contains one of the nuclei of the sheath of Schwann, and probably, together with the white substance of Schwann, represents a cellular element. Diseased conditions sometimes respect the limits of these cellular elements.

The central axis is the true conducting part of the nerve-fibre, and it is probable that each of the fibrillæ of which it is composed has a separate peripheral termination and possesses the power of isolated conduction. The white substance of Schwann and the sheath of Schwann protect the central axis and seem to be connected with its nutrition.

The fibres in a nerve are bound together by loose connective tissue, the endoneurium, into the primitive bundles, which are again united by the perineurium, a membrane of laminated connective tissue, into more definite funiculi seen by the naked eye, the secondary bundles.

The secondary bundles are tied together by connective tissue, in which are found fat-cells and in which run the fine blood-vessels supplying the nerves. This connective tissue has been named the epineurium, and its condensed outer layers constitute the sheath of the nerve. It is important to observe that the connective tissue of the nerves is permeated by lymphatics which penetrate to the nerve-fibres, so that these are brought in contact with, and as it were, bathed in, the lymph.

Each nerve-fibre runs an isolated course from end to end, without anastomosing with other fibres, and near its peripheral termination it usually divides into two or more branches.

The fibres of the peripheral nerves depend for their integrity and nutrition upon their connection with central organs. The large multipolar cells of the anterior horns of gray matter of the spinal cord preside over the nutrition of the motor fibres; the ganglia on the posterior roots of the spinal nerves over the nutrition of the sensitive fibres.

If a nerve be severed from its connection with these centres of nutrition, it in a short while undergoes degenerative changes which result in complete destruction of its fibres.

The nerve-fibres when in a state of functional activity conduct impressions along their length to the end-organs or to the nerve-centres with {1179} which they are in connection. This property of the fibres we call their conductivity. Each fibre conducts impressions in an isolated manner, not communicating them to other fibres with which it may be in contact. The rapidity of this conduction in human nerve-fibres is estimated at 33.9 meters (about 38 yds.) per second. This rate may be diminished by cold or by the anelectrotonic condition which is induced in the nerve by the passage through it of an electric current.

The nerve-fibres are irritable; that is, the application to them of stimuli excites their functional activity, and the impression made by the stimulus is transmitted to their extremities.[1]

[Footnote 1: The nerve-fibres in man do not appear to attain their full irritability until the fifth or tenth month after birth (Soltman).]

The natural or physiological stimuli of the nerves act upon their extremities. Either they act through the peripheral mechanisms, giving rise to impressions which are conducted centripetally to the cells of the nerve-centres and there cause sensations or reflex actions, or they act upon the nerve-centres, giving rise to impulses which are conducted centrifugally and cause the various phenomena of contraction of muscles, inhibition of contraction, secretion, etc. Besides the physiological, there are other stimuli which excite the functional activity of nerve-fibres when applied at any point along their course.

Mechanical stimuli, blows, concussions, pressure, traction, etc., excite the nerves, causing sensations when applied to sensitive nerves, or contraction of muscles when applied to motor nerves. When mechanical stimuli are pushed farther, the irritability of the nerves may be destroyed. The gradual application of mechanical stimuli may destroy the irritability of nerve-fibres without any exhibition of excitation, as in paralysis from pressure. In nerve-stretching it is probable that many of the results depend upon the mechanical stimulation of the nerve-fibres by the traction. With a certain amount of force used the irritability of the nerve may be increased; carried farther, both the irritability and the conductivity may be diminished, and finally destroyed. As the centripetal fibres are soonest affected in the stretching, we can see how this proceeding is most beneficial in neuralgias, where a potent factor, if not the cause of the disease, is an abnormal excitability of the nerve-fibres. It is to be observed, nevertheless, that in cases of continued pressure upon mixed nerves the motor fibres are the first to suffer loss of their conductivity.

Sudden alterations of temperature act as stimuli to nerves. Heat increases their irritability, but its prolonged application diminishes it. Cold in general diminishes the nervous irritability, and may be carried to the point of completely destroying it temporarily.[2]

[Footnote 2: But at a certain age in freezing the ulnar nerve Mitchell found its irritability notably increased.]

Many substances of widely-different chemical constitution, as acids, alkalies, salts, alcohol, chloroform, strychnine, etc., act as stimuli when applied directly to the nerves, apparently by causing in them rapid molecular changes. Also may be enumerated as chemical stimuli to the nerves substances found naturally in the body, as bile, bile salts, urea. The rapid withdrawal of water from nerve-tissue first increases, and then diminishes, its irritability. The imbibition of water decreases nervous irritability.

{1180} An electric current of less duration than the 0.0015 of a second does not stimulate the nerve-fibres. It would appear that more time is required for the electric current to excite in nerve-tissue the state of electrotonus which is necessary to the exhibition of its functional activity. The electric current stimulates a nerve most powerfully at the moments of entrance into and exit from the nerve, and the more abruptly this takes place the greater the stimulation. Thus the weak interrupted currents of the faradic or induced electricity owe their powerfully stimulating effects to the abruptness of their generation and entrance into and exit from the nerves. At the moment of the entrance of the electric current into the nerve—that is, upon closing the circuit—the stimulating effect is at the negative pole or cathode; when the current is broken—_i.e._ leaves the nerve—the stimulating effect is at the positive pole or anode. A current of electricity very gradually introduced into or withdrawn from a nerve does not stimulate it. But if while a current is passing through a nerve its density or strength be increased or diminished with some degree of rapidity, the nerve is stimulated, and the degree of stimulation is in proportion to the suddenness and amount of change in the density or strength of the current. Although with moderate currents the stimulation of the nerve takes place only upon their entrance and exit, or upon variations of their density, nevertheless, with a very strong current the stimulation continues during the passage of the current through the nerve. This is shown by the pain elicited in sensitive nerves, and the tetanic contraction of the muscles to which motor nerves are distributed.

An important factor in electrical stimulation is the direction of the current through the nerve. A current passed through a nerve at right angles with its length does not stimulate it. Currents passing through a nerve stimulate in proportion to the obliquity of their direction, the most stimulating being those passing along the length of the nerve. Motor nerves are more readily stimulated by the electric current the nearer it is applied to their central connection. Experiments on the lower animals would seem to indicate that the motor fibres in a nerve-trunk do not all show the same degree of irritability when stimulated by the electric current.

The irritability of the nerve-fibres may be modified or destroyed in various ways. Separation of nerves from their nutritive centres causes at first an increase of their irritability, which is succeeded by a diminution and total loss, these effects taking place more rapidly in the portions nearer the nerve-centres. It is important to observe that an increase of irritability preceding its diminution is generally observed in connection with the impaired nutrition of nerves, and is the first phase of their exhaustion.

Prolonged and excessive activity or disuse of nerves causes diminution of their irritability, which may go to the extent that neither rest in the one case nor stimulation in the other can restore it. If a galvanic current is passed through a nerve in its length, the irritability of the fibres is increased in the region of catelectrotonus—viz. in the part near the cathode—and diminished in the region of anelectrotonus—viz. in the part near the anode. Certain substances, as veratria, first increase and then destroy the irritability of the nerves; others, as woorara, rapidly destroy it.

{1181} The fibres of the peripheral nerves are divided into two classes: first, those which conduct impressions or stimuli to the nerve-centres, the afferent or centripetal fibres; and, secondly, those which conduct impulses from the centres to peripheral organs, the efferent or centrifugal fibres. Belonging to the first class are (1) sensitive fibres, whose stimulation sets up changes in the nerve-centres which give rise to a sensation; (2) excito-motor fibres, whose stimulation sets up in the nerve-centres changes by which impulses are sent along certain of the centrifugal fibres to peripheral end-organs, causing muscular contraction, secretion, etc. Belonging to the second class are (1) motor fibres, through which impulses are sent from the nerve-centres to muscles, causing their contraction; (2) secretory fibres, through which impulses from nerve-centres stimulate glands to secretion; (3) trophic fibres, through which are conveyed influences from the centres, affecting the nutritive changes in the tissues; (4) inhibitory fibres, through which central influences diminish or arrest muscular contraction or glandular activity. No microscopic or other examination reveals any distinction between these various fibres.

Every nerve-fibre has the power of conducting both centripetally and centrifugally, but the organs with which they are connected at their extremities permit the exhibition of their conductivity only in one direction. Thus, if a nerve-fibre in connection with a muscle at one end and a motor nerve-cell at the other be stimulated, although the stimulus is conducted to both ends of the fibre, the effect of the stimulus can only be exhibited at the end in connection with the muscle, causing the muscle to contract. Or if a fibre in connection with a peripheral organ of touch be stimulated, we can only recognize the effects of such stimulation by changes in the nerve-cells at its central end which give rise to a sensation.

When we consider the extensive distribution and exposed position of the peripheral nerves, their liability to mechanical injury and to the vicissitudes of heat and cold, we cannot but anticipate that they will be the frequent seat of lesions and morbid disturbances. It may be that not a few of their diseased conditions have escaped observation from a too exclusive looking to the central nervous system as the starting-point of morbid nervous symptoms. This occurs the more readily as many of the symptoms of disease of the peripheral nerves, as paralysis of muscles, anæsthesia, hyperæsthesia, etc., may equally result from morbid conditions of the brain or spinal cord, and not unfrequently the peripheral and central systems are conjointly affected in a way which leaves it doubtful in which the disease began or whether both systems were simultaneously affected.

The elucidation of such cases involves some of the most difficult problems in diagnosis, and requires not only a thorough acquaintance with the normal functions of the peripheral nerves, but also the knowledge of how those functions are modified and distorted in disease.

The symptoms arising from injuries and diseases of the peripheral nerves are referable to a loss, exaggeration, or perversion of their functions, and we often see several of these results combined in a single disease or as the result of an injury.

The fibres may lose their conductivity or have it impaired, causing feebleness or loss of motion (paralysis), or diminution or loss of sensation {1182} (anæsthesia). Or there may be induced a condition of over-excitability, giving rise to spasm of muscles and sensations of pain upon the slightest excitation, not only from external agents, but from the subtler stimulation of molecular changes within themselves (hyperæsthesia). Or diseased conditions may induce a state of irritation of the nerve-fibres, which shows itself in apparently spontaneous muscular contraction or in sensations abnormal in their character, and not corresponding to those ordinarily elicited by the particular excitation applied, as formication or tingling from simple contact, etc. (paræsthesiæ), or in morbid alterations of nutrition in the tissues to which the fibres are distributed (trophic changes).

If we could recognize the causes of all these varied symptoms and discover the histological changes invariably connected with them, it would enable us to separate and classify the diseases of the peripheral nerves, and give us a sound basis for accurate observation and rational therapeutics. But, although the progress of investigation is continually toward the discovery of an anatomical lesion for every functional aberration, we are still so far from a complete pathological anatomy of the peripheral nerves that of many of their diseases we know nothing but their clinical history. We are therefore compelled in treating of the diseases of the peripheral nerves to hold still to their classification into anatomical and functional, as being most useful and convenient, remembering, however, that the two classes merge into each other, so that a rigid line cannot be drawn between them, and that such a classification can only be considered as provisional, and for the purpose of more clearly presenting symptoms which we group together, not as entities, but as pictures of diseased conditions which may thus be more readily observed and studied.

It is well to begin the study of the diseases of the peripheral nerves by a consideration of nerve-injuries, because in such cases we are enabled to connect the symptoms which present themselves with known anatomical alterations, and thus obtain important data for the elucidation of those cases of disease in which, although their symptomatology is similar, their pathological anatomy is imperfectly or not at all known.

Injuries of the Peripheral Nerves.