Electrotherapy

The experimenters of the eighteenth century inherited from Robert Boyle, who in 1673 and 1675 described electric attraction as “a Material Effluvium, issuing from and returning to, the Electrical Body.” This concept, when applied to the nervous system, retained a flavor of galenism’s nervous fluids and the vis nervosa of von Haller, and permeates nearly all the writings of the experimenters in this field until vitalism finally gave way to materialism.

Working at first only with frictional machines as a source of electricity, experimenters in the early eighteenth century played with many demonstrations of its strange action at a distance. This was a period when interest in electricity was so keen that it was invoked to explain many natural phenomena, not only of animals but also of plants. According to Fée (1832), Elizabeth, the daughter of the great Linnaeus, noticed in her father’s garden near Uppsala that some of the orange-colored flowers, such as marigolds and firelilies, appeared to give off flashes of light at twilight. (It was Goethe, in 1810, who showed this to be a retinal contrast effect and not an electrical flash.) But those who speculated about animals and man felt that they were on surer ground. Did not the cat’s fur crackle when you rubbed it, and had not Theodoric the Visigoth thrown off sparks as he marched?

In the early part of the century it had been discovered empirically that the human body could be charged electrostatically, provided that it was insulated. At first it was thought that a layer of air had to be present between the subject and the ground, for the characteristics of conductors and nonconductors were only beginning to be understood. Stephen Gray, who died in 1736, discovered in 1731 that the distribution of electric charges varies with the insulating or conducting properties of the material employed, and he had reported these findings in a series of letters to the Royal Society. These terms were not used at the time, nor was induction understood (which he had demonstrated and called “Electrical Attraction at a Distance”). He wrote of “Electrick Virtue,” and said that his experiments showed that animals “receive Electrick Effluvia.” In 1742 his teacher, Desaguliers, a demonstrator for Newton, clarified the distinction between conductors and nonconductors, showing the former to be essentially the “non-electrics” of Gilbert that conveyed electricity away, and the latter to be the “electrics” that could be charged.

In many countries the phenomenon by which the human body could carry a charge was exploited for entertainment. Outstanding examples were the Abbé Nollet at the Court of Louis XV, Winkler and Hausen at Leipzig, Du Fay in Paris, and Kratzenstein in Halle ( Fig. 1-1 ). Many delightful illustrations survive.

Electrification of the human body by frictional electricity.

(From Krüger JG: Zuschrift an seine Zuhörer worinnen er ihren seine Gedancken von der Electricität mittheilet. Hemmerde, Halle, 1745.)

The next step was the discovery that the application of electricity to muscles, even those of the dead, could evoke a contraction. Inevitably, this led to the exploitation of this effect as a therapy despite a complete lack of understanding of its modus operandi. Some attempts were deliberate hoaxes; others—for example, those of the physicians at the center at Montpellier—were the efforts of true believers.

Among these believers was a young physician named Kratzenstein, who was raised in the unlikely atmosphere of the Stahlian school in Halle but was greatly influenced by his teacher, Gottlob Krüger. Krüger, beginning to draw away from the influence of Georg Ernst Stahl (who taught that the soul was the vital force that caused muscles to contract ), had experimented widely with the electrification of animals and encouraged his pupil to engage in electrotherapeutic studies. These were first printed in 1744 in the form of letters entitled “Abhandlung von dem Nutzen der Electricität in der Arzenwissenschaft.”

Still using frictional electricity, and noting from experiments on himself that electrification of his body caused him to sweat (the “effluvium” of Boyle?), Kratzenstein advanced the hypothesis that this loss of salt-containing fluid could have beneficial medicinal effects. No doubt this proposal stemmed from the age-old concept that bloodletting had therapeutic value.

The cures he claimed consisted of two cases in which there was restoration of movement in contracted fingers. He also noted the induction of sound sleep, forerunner of that observed in electrosleep. As the news spread around Europe, attempts at cures were made in many centers. These were at first mostly in cases of paralysis. The fact that contraction of a muscle could be obtained at the moment of direct stimulation yet could not be maintained as a cure failed to find correct interpretation, for the role of innervation was not yet understood.

The rare case of success anteceded the understanding of hysterical paralysis and encouraged the establishment of many centers for the treatment of paralytic conditions, among the most famous being the school of Montpellier under the leadership of Boissier de la Croix de Sauvages. In 1749, one of de Sauvages’s pupils, Deshais, published a thesis boldly entitled “De Hemiplegia per Electricitatem Curanda,” which showed his thinking to be creeping toward the recognition of the role of the nerve supply, although this was still versed in galenist terms. Deshais wrote, “paralysis is caused by the arrest of nervous fluid destined to circulate in the brain because it meets an insuperable resistance in the nerve fibres. Thus we must increase the pressure of the nervous fluid when hemiplegia resists ordinary remedies.” He added that hemiplegia could be cured or, at any rate, improved by electrification ( Fig. 1-2 ).

Title page of the doctoral thesis of J. E. Deshais on the cure of hemiplegia by electricity.

(Courtesy of the University of Montpellier.)

At this time, electricity and its effects on the human body were a favorite subject for theses. In the collection of unpublished manuscripts (1750–1760) by Jacques de Romas that is preserved in the City Archives of Bordeaux, there is one on electricity that includes observations on the electrification of two paralytic patients. Another example is found in the thesis collection at the University of Montpellier, written in 1750 by Jean Thecla Dufay, who restricts himself to the electrical nature of the nervous fluid and does not discuss therapy. His thesis does, however, give a useful review of the experiments and knowledge of his time. He concludes his account boldly: “Ergo Fluidum nerveum est Fluidum electricum.” Montpellier was at that time a center of great interest in electricity, and it was there that Boissier de Sauvages endowed a convent hospital solely for electrical therapy (1740–1760). In 1748, de Sauvages had himself received a prize from the Académie Royale des Sciences at Toulouse for a dissertation on hydrophobia; this was published in 1758. In this paper, in what he termed a “Digression sur l’électricité,” he championed the existence of animal electricity and evolved a bizarre hypothesis about nerve and muscle activity in hydrophobia. This went as follows: given that muscular movement is proportional to the force of the nervous fluid, the venom of rabies, on mixing with it, doubles the velocity and also doubles the density of the nervous fluid; hence the nerve force and the resultant muscular movement are eight times stronger than normal. By this tortuous piece of arithmetic, de Sauvages explained the violent muscular spasms in hydrophobia.

Academies were generous with prizes for the medical uses of electricity, which no doubt accounts in part for the plethora of such theses at this time. Another winner was Jean-Paul Marat, who was to meet a violent death in the French Revolution. His essay won the prize of the Paris Academy but drew the rebuke that his criticisms of other workers were too forcefully expressed. Many absurd claims for electrotherapy were made by physicians, and at their doors must be laid the blame for much subsequent quackery. A contemporary critic ridiculed these claims but published only anonymously; however, his gay and witty touch betrayed his identity to Nollet as that of another gentleman of the Church, the Abbé Mangin. Nollet, who had himself gathered acclaim through his use of electrotherapy (though he had also done his part to expose the quacks), scolded Mangin “d’avoir confondu les temps, les lieux, les personnes et les choses.”

A more efficient source of electricity was to come to the aid of electrotherapists, although a natural one had, in fact, been used for some years: namely, the shock delivered by the marine torpedo. On being applied to the soles of the feet, this was said to relieve the pain of gout. The rationale for the treatment, however, received no elucidation from the great surgeon, John Hunter, whose exquisite dissections revealed the anatomy of these electric fish, for he thought that “the will of the animal does absolutely controul the electric powers of its body.” The reflex nature of the discharge was not established until the serial experiments of Matteucci and Savi in 1844.

By the middle of the eighteenth century, eager electrotherapists were no longer dependent on the frictional machines for producing electricity, for van Musschenbroek, Professor of Physics at Leiden, almost by chance invented a device for storing electricity and discharging it as a shock. This, the ancestor of the condenser, was the Leyden jar.

In 1746, van Musschenbroek, striving to conserve electricity in a conductor and to delay the loss of its charge in air, attempted to use charged water as the conductor, insulating it from air in a nonconducting glass jar. However, when he charged the water through a wire leading from a frictional electrical machine, he found the electricity dissipated as quickly as ever. An assistant who was holding the jar containing charged water accidentally touched the inserted wire with his other hand and got a frightening shock. With one hand he had formed one “plate,” the charged water being the other “plate,” and the glass jar the intervening dielectric. A condenser was born. Experimental electricity had reached the stage when such a development was due, for a similar discovery was made by the Dean of the Cathedral of Kamin in Pomerania, whose followers gave the jar his name, “Kleiste Flasche.”

One of the many to espouse this new electrifying technique was the Abbé Bertholon, who traveled widely in Europe, bringing back reports of strange cures that others could not replicate. He was not alone in the variety of claims he made, for this form of “therapy” had spread widely through Europe. So diverse were the diseases for which cures were being claimed that academies in several countries offered prizes, including the Académie at Lyons. It offered a prize in 1777 for the answer to the questions, “Quelles sont les maladies qui dépendent de la plus ou moins de grande quantité de fluide électrique dans le corps humain, et quels sont les moyens de remédier aux unes et aux autres?” This was a spur to many, including Bertholon, who, in his two volumes on the electricity of the human body in health and disease, claimed to examine his cases as to whether electrification was the only ameliorator of the patient’s condition or was an additive to other therapies. A great believer in a “latent electricity” within the body, he held that it was manipulation of this inherent electricity that formed the basis of the cures he claimed. This concept was a rewording of “animal spirits,” and in no way did he foresee the intrinsic electricity of nerve and muscle found (but little understood) by Galvani.

We owe the next step in the invention of sources of electricity to the controversy that developed with Volta over the explanation of Galvani’s results ; the voltaic pile, which soon replaced the Leyden jar in the hands of those espousing electrotherapy, was the ancestor of the batteries of today. By the turn of the century, books were beginning to appear on the history of medical electricity (e.g., by Vivenzio in 1784 and Sue in 1802).

The early ventures in applying electricity to patients with various diseases were gradually sorted out and achieved a rational basis, thanks to the development of knowledge of basic neurophysiology with its elucidation of the relationship of nerve to muscle, of spinal cord to nerve, and of brain to all. However, one method, for which therapeutic claims were made, has still not reached the first stage of scientific rationale. This is electroconvulsive shock.

Many early experimenters (e.g., Fontana in 1760 and Caldani in 1784) noted the convulsions of their frogs when electricity was applied to their brains, although Galvani attempted this without success. (“Si enim conductores non dissectae spinale medullae, aut nervis, ut consuevimus, sed vel cerebro-contractiones vel nullae, vel admodum exiguae sunt.”) In the first decade of the nineteenth century, his nephew, Aldini, was to experiment with electroshock in humans. Impressed by the muscular contractions he obtained on stimulating animals and cadavers, he stood close to the guillotine to receive heads of criminals in as fresh a condition as possible. He found that passing a current either through the ear and mouth or through the exposed brain and mouth evoked facial grimaces. The fresher the head, the more remarkable the grimace. He then proceeded to apply electrical stimulation from a voltaic pile to the living. His theory was that the contractions were excited by “le développement d’un fluide dans la machine animale,” and this he held to be conveyed by the nerves to the muscles. We recognize here the explanation popularized by Bertholon.

One set of these early experiments on humans reaches into the twentieth century, for Aldini applied his galvanism to the mentally ill ( Fig. 1-3 ). Having experimented on himself with electrodes in both ears or in one ear and his mouth, or on forehead and nose, he experienced a strong reaction (“une forte action”), followed by prolonged insomnia lasting several days. He found the experience very disagreeable but thought the changes it produced in the brain might be salutary in the psychoses (“la folie”). Passing the current between the ears produced violent convulsions and pain, but he claimed good results in patients suffering from melancholia.

Aldini’s experiments with electroshock “therapy” in humans. Above, mental patients with the electrodes in various positions connecting to voltaic piles for stimulation. Below, two recently dead patients connected directly, or by saline baths, to voltaic piles.

(From Aldini G: Essai Théorique et Expérimental sur le Galvanisme. Fournier, Paris, 1804.)

Aldini had no instrument to tell him the amount of current passed (he recorded only the number of copper and zinc discs in the voltaic pile). In the twentieth-century adaptation of this technique, we are also not told by the originator what current flowed between electrodes placed bilaterally on the frontoparietal regions, only the voltage (although it is current, and not voltage, that stimulates). “I decided to start cautiously with a low-intensity current of 80 volts for 1.5 seconds … The electrodes were applied again and a 110-volt discharge was applied for 1.5 seconds.” We are not surprised to be told of the resultant convulsion, apnea, and cyanosis.

This report related the results of the first experiments made by Cerletti in 1932, but even now, many years later, no rationale has been found for the salutary effects claimed by the users, and one is reminded again of Aldini’s concept of a rearrangement of functions in the brain such as take place from a hit on the head: “Une chute, un coup violent porté sur la tête, ont souvent produit des altérations très sensibles dans les facultés intellectuelles.”

In the years following Aldini’s application of electricity to humans, a revival of electrotherapy resulted from the work of Duchenne, who stimulated paralyzed muscles, at first through punctures of the skin but later percutaneously. Although considerable controversy arose from his work, he had, in fact, a greater understanding of electric currents than his predecessors, and by careful exploration he found the motor points for the muscles he was stimulating. From his work grew some understanding of the anatomy underlying the induced contractions of muscles, and in 1868 he published a small book on muscular paralysis, in which he illustrated the muscle fiber abnormalities he found by light microscopy. It may be said that it was Duchenne who built the bridge between electrotherapy and electrodiagnosis, leaving his name to Duchenne dystrophy.

A less controversial ancestor of modern electrical techniques (the cardiac stimulator) is found in a report given to the Accademia di Torino in 1803, in which the hearts of three decapitated felons were found to retain excitability long after the voluntary muscles ceased to respond to galvanic stimulation. The reporters were Vassalli, Giulio, and Rossi.

Before the end of the nineteenth century, stimulation of the heart by alternating currents was being used in France for resuscitation by Prévost and Batelli, and it developed into a standard procedure in the twentieth century.