Page:The American Cyclopædia (1879) Volume VI.djvu/696

 684 EPILEPSY when he recovers he remembers nothing that has taken place in the mean time. In some cases the seizure is followed by a prolonged coma, ending sometimes in death. When the patient recovers from a tit, even if it has not been very severe, he usually feels fatigued and suffers from headache. Fortunately he soon falls asleep, and ordinarily is almost as well as usual when he wakes, except that the headache and the fatigue still exist, though much di- minished. When many fits have taken place, even at somewhat long intervals, such as sev- eral weeks, mental derangement often super- venes, and in this way epilepsy leads to insan- ity. In some cases the fits recur at regular periods; in others they return with every return of the circumstances which seem to have caused the first, such as menstruation, pregnancy, the influence of certain seasons, &c. There is seldom perfect regularity in the length of the intervals between the fits, and they come every day, every week, every month, &c., at irregular hours. Many patients have very different intervals between their succes- sive fits. Some have many fits a day, others one every six months, or every year. Dela- siauve mentions a case in which the number of fits was 2,500 in a month. But the greater the number of fits, the less violent they gen- erally are. In a complete, fit of epilepsy there are two distinct features : 1, the loss of con- sciousness; 2, the muscular convulsions. Each of these may exist alone. In the case of a seizure consisting only in the loss of conscious- ness without convulsions, we have the so-called epileptic vertigo, which is a form of epilepsy that frequently exists alone, and also coexists often with the form of the disease in which the attack is complete. In this last case the patient sometimes has a complete seizure, sometimes only an attack of vertigo. Whether vertigo exists alone or coexists with complete attacks, it is very dangerous, not for the life of the patient, but because fits of simple ver- tigo lead more frequently to insanity than complete fits of epilepsy. The cases of epi- leptiform convulsions without loss of conscious- ness are not so frequent as the cases of simple vertigo. They are particularly produced by injuries to the nerves or to the spinal cord. The nature of epilepsy, the material and dy- namical conditions of the parts which are affected in the animal organism, have been greatly illustrated by the researches of modern physiologists and practitioners. Dr. Marshall Hall thought its seat to be chiefly in the me- dulla oblongata, and that its nature consisted in an increased reflex power, at least in the beginning of the disease, and also that the con- vulsions were the results of the asphyxia caused by ^ the closure of the larynx (laryngismus). This theory is in opposition to several facts. In the first place, although laryngismus almost always exists and certainly concurs in the pro- duction of asphyxia, and in so doing generates convulsions, it cannot be considered the cause of convulsions, as it does not always exist, and as there is one kind of convulsions (the tonic) which precedes the asphyxia. Besides, there are more powerful causes of asphyxia in the condition of the circulation in the brain and the spasm of the muscles of the chest. Then, as regards the increased reflex power, Dr. Hall acknowledges that this power is diminished in persons who have been epileptic for some time. We cannot admit therefore that the disease consists in the increase of this power. Another theory has been proposed by Dr. Brown-Se- quard. Guided by experiments on animals, in which he produces epilepsy, he has found that the reflex power is composed of two distinct powers, one of which he calls the reflex force and the other the reflex excitability. He has found that the reflex force may be very much diminished while the reflex excitability is very much increased. This last power is the power of impressibility of the cerebro-spinal axis ; in epileptics this impressibility is very much aug- mented. The slightest excitations may pro- duce reflex actions in them. In the beginning of epilepsy, usually the other reflex power, which is the force manifested in the reflex ac- tions of the cerebro-spinal axis, is increased ; but after a time this force diminishes, and in most cases it becomes less, and even much less, than in healthy people. The nature of epilep- sy seems to consist in an increase of the im- pressibility, or in other words of the reflex ex- citability of certain parts of the cerebro-spinal axis. In most cases of epilepsy these parts are the medulla oblongata and the neighboring parts of the encephalon and of the spinal cord. But the seat is not constant, and may be some- times limited to the oblong medulla or extend- ed to other parts of the cerebro-spinal axis. Dr. Brown-S6quard has tried to explain the mysterious phenomenon of loss of conscious- ness. It seemed very strange that at the same time that certain parts of the encephalon were acting with great energy, another part should be completely deprived of action. This, accord- ing to him, is very simple. The blood vessels of that part of the brain which is the seat of consciousness and of the mental faculties re- ceive nerves from the medulla oblongata and the spinal cord ; these blood vessels when they are excited contract and expel the blood they normally contain, and it is known that all the functions of that part of the brain cease when they do not receive blood. When the excita- tion that exists in the beginning of a fit acts upon the medulla oblongata and its neighbor- hood, it produces at the same time the contrac- tion of the blood vessels of that part of the brain which we have mentioned, and a convul- sive contraction of the muscles of the face, the eye, the neck, the larynx, &c., all parts receiv- ing nerves from the same source as these blood vessels. In this way the loss of consciousness is explained. The following table from Dr. Brown-S^quard's work on epilepsy shows how the principal phenomena are generated :