A system of practical medicine. By American authors. Vol. 5

by Unknown

¹⁰ Berger, Deutsche medizinische Wochenschrift, 1885, 1 and 2.

The disturbance of co-ordination above spoken of as manifested in the inability of the patient to stand well with his eyes closed is the first step in the development of the characteristic ataxia which marks the full-blown affection. The patient finds that he tires more and more on slight exertion—not because his muscles are weak, but because he has to make more voluntary effort than a person in health. He finds that he stumbles easily—is unable to ascend and descend at the curbstone or to walk over an irregular surface with ease. Going down stairs is peculiarly irksome. “I would rather,” aptly said one patient, “troubled as I am in walking, go a mile in the street than walk up three flights of stairs; but I would rather go up six flights of stairs than walk down one.” Soon the patient notices that walking in the dark becomes more a feat of relative skill than the easy, almost automatic, act it was in health. His vocation, if it was one involving the use of the feet, becomes irksome, difficult, and finally impossible, and in a number of cases the upper extremities are also involved.¹¹ Delicate motions, such as those required in needlework, in writing, and by watchmakers, musicians, opticians, and lapidaries, are clumsily performed; even coarser movements, such as buttoning the clothes and carrying a glass filled with water to the mouth, are performed in an uncertain and clumsy manner. Meanwhile, the disturbance of motion in the lower limbs progresses. Difficult as it formerly was for the patient to stand on one foot or with both feet together while the eyes were closed, he is now unable to do either with the eyes open. He straddles in his walk, or, in order to overcome the element of uncertainty involved in moving the knee-joint, keeps this joint fixed and walks with short, stiff steps. If ordered to halt suddenly while thus walking, the patient sways violently, and makes movements with his hands or arms to recover his balance, in some cases staggering and even falling down. He shows a similar unsteadiness when told to rise suddenly from a chair or to mount one, and it becomes impossible for him to walk backward. Later on, it will be found that his feet interfere in walking. He has lost the power of gauging the extent and power of his motions to such a degree that he may actually trip himself up. To neutralize in some way this element of uncertainty of his steps, the patient is compelled to exaggerate all his ambulatory movements, and there results that peculiar gait which was the first symptom directing attention to the disease to which it is due. The feet are thrown outward, and violently strike the ground; the heel touches the latter first, and the patient appears as if he were punishing the ground and stamping along instead of walking. The reason for his adopting these tactics are twofold. In the first place, he has a subjective sense of walking in a yielding substance, as if on a feather bed, air-bladders, cushions, or innumerable layers of carpet, and he therefore makes efforts to touch firm bottom. In the second place, his motor inco-ordination, in so far as it is not the result of anæsthesias, is greatest in those segments of his limbs which are farthest removed from the trunk, and which, enjoying the greatest freedom of combined motion, are also most readily disturbed. His uncertainty is therefore greater in the toes than in the ankle, greater in the ankle than in the knee, and greater in the knee than in the thigh: he prefers to touch the ground with the heel to touching it with the toes, and to move his limb in the hip than in the knee-joint. As the patient advances in life even this limited and clumsy form of locomotion becomes impossible: he takes to his bed, and it is found that he loses all sense of the position of his lower and occasionally of his upper limbs. He is unable to tell which limb overlies the other when his leg is crossed—unable to bring one limb in parallel position with another without the aid of his eyes. If told to touch one knee or ankle with the toes of the other side, his limb oscillates around uncertainly, and makes repeated unskilful dashes at the wrong point, and ultimately all but the very coarsest muscular co-ordination appears to be lost, even when the supplementary aid of the eyes is invoked.

¹¹ Cases in which the upper extremities are intensely involved in the beginning are uncommon, and those in which they are more intensely involved than the lower, or exclusively involved, may be regarded as pathological curiosities.

Together with this gradual impairment and abolition of co-ordination, which has given the name of locomotor ataxia to the disease, but not always in that strict parallelism with it on which Leyden¹² based his theory of inco-ordination, the sensory functions proper become perverted and impaired. Usually the determinable anæsthesias are preceded by subjectively perverted sensations, such as the numbness already referred to, or even by hyperæsthesia. Usually, all categories of cutaneous sensation, whether special or pathic, are impaired in advanced tabes; the points of the æsthesiometer are not readily differentiated; the patient is unable to correctly designate the locality which is touched or pinched; the pain-sense is occasionally so much blunted that a needle may be run through the calf of the leg without producing pain, and in some cases without being appreciated in any form. Even if the pain-sense be preserved, it will be found that its appreciation by the patient is delayed as to time. Not infrequently bizarre misinterpretations are made of the impressions acting on the skin. One of these, the feeling as if the patient were standing on carpet, cushions, or furs, whereas he may be standing on stone flagging, has already been mentioned as a factor in the disturbed locomotion of the patient. In the later period, numerous perversions of this kind are noted: to one of these, already mentioned by Leyden, Obersteiner has called renewed attention. It consists in a confusion of sides; the patient when pricked or touched on one foot or leg correctly indicates the spot touched, but attributes it to the wrong side.¹³

¹² Klinik der Rückenmarkskrankheiten, Band ii.

¹³ Allochiria is the term applied by Obersteiner. Hammond has offered an explanation, which, as it is based on the assumption of altogether hypothetical nerve-tracts, and not in any sense accords with positively established facts, is more properly a subject for consideration in a theoretical treatise.

While it may be affirmed, as a general proposition, that the tendency of the tabic process is to abolish sensation below the level of the disease, there are noteworthy exceptions, not only in individual cases, but with regard to certain kinds of sensation; nor do the different kinds of sensation always suffer together. Thus, the pain-sense may be blunted and the contact-sense preserved, or, more commonly, the latter blunted and the former exaggerated, so that the unfortunate patient, in addition to being debarred of the useful varieties of sensation, those of pressure and space, has the painful ones exaggerated, as a hyperalgesia. According to Donath,¹⁴ the temperature-sense is usually blunted in tabes, and a greater degree of heat or cold can be borne without discomfort than in health; but in about two-sevenths of the cases studied there was increased sensitiveness to heat, and in one-seventh to cold. One of the commonest manifestations is delayed conduction. This interesting phenomenon has been especially observed in that phase of the disease where tactile perception is beginning to be blunted. If the patient be pricked with a pin, he feels the contact of the latter at the proper moment as a tactile perception, and then after a distinct interval, varying from one to four seconds, his limb is suddenly drawn up and his face contorted under the influence of an exaggerated pain. This fact furnishes one of the chief grounds for the assumption that there are distinct channels for the transmission of pain and tactile perception in the cord, and that they may be involved separately or with different intensity in the disease under consideration. In some advanced cases it is found that not only the transmission of pain-appreciation is delayed, but that there are after-sensations recurring at nearly regular intervals of several seconds, and accurately imitating the first pain-impression.

¹⁴ Archiv für Psychiatrie, xv. p. 707.

To what extent the muscular sense is affected in tabes at various stages of the disorder is somewhat in doubt. Strümpell¹⁵ by implication, and other writers directly, attribute the inco-ordination observed on closing the eyes to the loss of the muscular sense. As this symptom is also observed in patients who when they lie on their backs are able to execute intricate movements notwithstanding the exclusion of the visual sense, and as their uncertainty in an early stage is not always with regard to the position of their limbs nor the innervation of individual or grouped muscles, it seems inadmissible to refer the Romberg symptom¹⁶ to the loss of muscular sense alone.