Sleep and Its Derangements

by William A. Hammond

Darwin gives a very striking example of the independent action of the brain and spinal cord. A young lady was playing on the piano a very difficult musical composition, which she performed with great skill and care, though she was observed to be agitated and preoccupied. When she had finished, she burst into tears. She had been intently watching the death-struggles of a favorite bird. Though her brain was thus absorbed, the spinal cord had not been diverted from the office of carrying on the muscular and automatic actions required by her musical performance.

The brain cannot entertain two ideas or initiate two acts at the same time. A person cannot, for example, think of a lamp and a book simultaneously; the thought of the one and the thought of the other will be found to alternate by any one who feels inclined to make the experiment, and not to exist at the same time. Neither can the brain think and simultaneously will. Whatever volitional acts it performs, are distinct from thought, and clearly separated from it by the element of time.

Now in all sleep there is more or less somnambulism, because the brain, according as the sleep is more or less profound, is more or less removed from the sphere of action. If this quiescent state of the brain is accompanied, as it frequently is in nervous and excitable persons, by an exalted condition of the spinal cord, we have the higher order of somnambulic phenomena produced, such as walking and the performance of complex and apparently systematic movements; if the sleep of the brain be somewhat less profound, and the spinal cord less excitable, the somnambulic manifestations do not extend beyond sleep-talking; a still less degree of cerebral inaction and spinal irritability produces simply a restless sleep and a little muttering; and when the sleep is perfectly natural, and the nervous system of the individual well balanced, the movements do not extend beyond changing the position of the head and limbs and turning over in bed.

As regards the power of the spinal cord to supply the nervous force requisite for the performance of such actions as those specified, I do not think there can be any question. Much observation and many experiments have convinced me that the importance of the spinal cord as a center of intellection and volition has been unwarrantably ignored. It is of course not a matter for doubt that the faculty of consciousness is latent in the spinal cord so long as the brain is in a state of activity, and that the faculty of memory does not reside in it at all. When the brain acts, it ordinarily assumes the control of the cord; but there are times, especially during the course of certain diseases, when the latter obtains the mastery over the superior organ and dominates with terrible power.

The actions initiated by the spinal cord are more or less automatic in their character—though not altogether so. The motions of a frog deprived of its brain, show a certain amount of intellection and volition. That they are not more extensive is probably due to the fact that all the organs of the senses, except that of touch, have been removed with the brain. In persons engaged in intense thought and performing actions not in accordance therewith, the impressions made upon the organs of the senses are not appreciated by the brain, but pass through its substance to the spinal cord with which they are in connection by continuity of structure, and which initiates the subsequent actions.

In the somnambulic individual the brain is still more incapable of receiving sensorial impressions. Whatever sense is therefore exercised during the condition of somnambulism, owes its activity to the spinal cord; but in most cases of the state in question, the brain is so profoundly asleep that it does not even transmit impressions to the cord, and hence there are no sensations at all, except that of touch, unless the irritations capable of exciting them are extraordinarily great.

In artificial somnambulism—the hypnotism of Braid—the spinal cord acquires a very high degree of susceptibility to sensorial impressions, and the brain is even more incapable than in natural somnambulism of asserting its superiority. But the consideration of this interesting branch of the subject does not enter into the plan of the present work.

The causes of somnambulism are generally to be found inherent in the organism of the individual, though they may be excited to activity by many circumstances which are capable of exhausting the nervous system or producing emotional disturbance. Young persons are more subject than those of maturer age, and there are few children who do not exhibit at some time or other manifestations of the condition in question, such as muttering and talking in their sleep, laughing, crying, or getting out of bed. Persons of the nervous temperament are those most liable to be affected. In four cases of chorea which have come under my care, the subjects were sleep-walkers in their youth, and the young lady whose case I have related was choreic at the time.

In regard to the treatment there is not much to be said. In the great majority of cases the affection yields readily to appropriate measures; the most efficacious of which consists in means adapted to break up the habit. This may be done by waking the patient before the expected paroxysm, or by placing a tub of cold water so that the feet will be put into it on the attempt to leave the bed. Full exercise in the open air, the avoidance of luxurious habits, and sleeping with the head well raised, are always beneficial.

Of medicines, I have no experience except with the bromide of potassium, and those calculated to improve the tone of the nervous system. The former I have used in two cases with entire success. One of them was that of the young lady, the details of whose case I have related; the other that of a gentleman, forty years of age, who became somnambulic from mental excitement, due to the extensive business operations in which he was engaged. Large doses of this remedy—forty to sixty grains taken at bedtime, and smaller doses, ten to thirty grains, taken twice through the day—broke up the habit entirely in a few weeks. Among the other remedies, I have employed phosphorus, strychnia, and iron with manifest advantage. Cold baths are generally useful. I am acquainted with a young lady who cured herself by taking a cold bath every night just before going to bed. The so-called antispasmodics can scarcely be useful.