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with a medical colleague, he had observed the particular symptoms of this affection, unfortunately remained unpublished, twenty years more elapsed before the first accurate and detailed description of the symptoms and progressive nature of this disease under the name of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.
1 Clinique médicale de l'Hôtel Dieu de Paris, vol. ii. p. 334.
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 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 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.