DIAGNOSIS TECHNOLOGY

Electrocardiograph

The electrocardiograph, an instrument designed to measure the electrical currents of the heart, was invented in 1924. Willem Einthoven was responsible for this new invention, which grew out of his work regarding the nature of heart action in disease as well as in health.

Unsatisfactory Instrumentation

Einthoven at first attempted to measure these currents by using the Lipp-mann capillary electrometer and various other instruments Einthoven built to aid his research. He found the capillary electrometer to be severely restrictive, but he was able to develop a way to correct its limitations. Still not satisfied with the available instrumentation and frustrated by the time and labor required for the current mechanisms to be effective, he searched for another means of recording the electrical currents attending the heartbeat.

A New Invention

The string galvanometer was Einthoven's answer to the limitations of other instruments. He described his new instrument and its relation to his experiments in electrocardiography in a series of papers. These papers dealt so completely with the field that little of major importance has been added that Einthoven did not at least touch on in his original research. For example, his first paper on electrocardiography noted a case of auricular fibrillation, although he was not yet aware of its significance. More than half a century after its invention, the electrocardiograph is still a major diagnostic tool in heart disease.

Psychophysiology Faces Change

As neurologists and psychiatrists in the later nineteenth century searched for a better understanding of brain function and its relation to mental processes, a renegade German scientist and psychiatrist developed a new approach. Always considered an outsider, Hans Berger dismissed the popular theories regarding the mind-brain relationship and sought a method grounded in the natural sciences. Berger's research led him on a search for a method to measure human brain-wave patterns and culminated in the development of the electroencephalograph.

Early Attempts

After disillusioning attempts at measuring changes in brain circulation and changes in the temperature of the brain during mental activity, Berger realized that studying the electrical activity of the brain would provide more insight into mental functioning and disturbances. Although Berger's knowledge of electrophysiology and physics was limited, he made his first attempt at recording the electrical impulses of the brain in 1920. This first experiment consisted of stimulating the cortex of patients with skull defects by applying electrical current to the skin covering the defect. The attempt was unsuccessful, but Berger continued his research and successfully recorded the first electroencephalogram (EEG), or brain-wave pattern, in 1929.

An Exciting Discovery

Berger's success was primarily due to his creating the appropriate instrument, the electroencephalograph. The instrument used pairs of electrodes placed on the scalp to transmit a signal to one of several recording channels of the electroencephalograph. The signal conveyed the difference in voltage between the pair, and the rhythmic fluctuation of the difference was shown as waves on a line graph.

Doubts

Bergeri research was monumental, and the potential impact of such a discovery was great, but the scientific world regarded this new diagnostic tool with open disbelief. Even Berger himself was not completely confident in the reliability of the EE C However, as he continued to study the working of the brain and the connections between parts of the central nervous system, he became convinced of the significance of the EEG. He published a series of fourteen papers in an effort to explain his research and win over the scientific community, and interest in the EEG eventually spread throughout the Western world.

Significance

By the time Berger published his last paper in 1938, the EEG was firmly entrenched as a medical diagnostic method. The EEG was somewhat limited as a research tool because it recorded only a small sample of electrical activity from the brain surface. Nevertheless, electroencephalography has proved to be vital in cases of serious head injury, brain tumors, cerebral infections, and various degenerative diseases of the nervous system. The electroencephalograph may be viewed as initiating a new era in neurophysiology, and Hans Berger may be called a true pioneer of medicine.

Cancer Test

In medical research the study of one subject often leads to a momentous discovery in another area. Such was the case with the research of George N. Papanicolaou, a Greek physician who immigrated to the United States in 1913. Papanicolaou worked at New York's Cornell Medical College in the area of cytology, specifically studying sex determination in guinea pigs. His research eventually led to a modern method for early detection of cancer in humans.

A Better Understanding

Papanicolaou's research required that he design a way to examine vaginal discharges of female guinea pigs. By microscopically studying the discharged cells, the doctor noted changes in their size and shape that correlated with the changes in the uterus and ovaries during the guinea pig menstrual cycle. Extending his theories to humans, Papanicolaou identified similar changes in the vaginal cells of women. More important, research showed clearly abnormal cells in the vaginal fluid from a woman diagnosed with cervical cancer. It was a short step from this discovery to Papanicolaou's development of the "Pap smear" as a method of early cancer detection.

Irrefutable Findings

A paper on the new cancer detection method was published in 1928 with Papanicolaou predicting that "a better understanding and more accurate analysis of the cancer problem is bound to result from use of this method. It is possible that analogous methods will be developed for the recognition of cancer in other organs." Although gynecologists initially preferred older methods of uterine cancer diagnosis to the new Pap smear, Papanicolaou's findings became irrefutable and were widely accepted by 1948.

Significance

Clearly, the Pap smear was a critical discovery. The method was able to detect cancer of the uterus five to ten years before symptoms appeared, and, as Papanicolaou predicted, the use of the Pap smear was extended to diagnosing cancer in other tissues of the body, such as the colon, kidney, bladder, prostate, lungs, breast, and sinuses.

Sources:

Daniel E, Carmichael, The Pap Smear: Life of George Papanicolaou (Springfield, 111.: Thomas, 1973);

Mary Erlichman, Electroencephalographic (EEG) Video Monitoring (Rockville, Md.: United States Department of Health and Human Services, 1990);

L. J. Rather, The Genesis of Cancer: A Study in the History of Ideas (Baltimore: Johns Hopkins University Press, 1978);

Donald F. Scott, Understanding EEG: An Introduction to Electroencephalography (Philadelphia: Lippincott, 1976);

Wrynn Smith, A Profile of Health and Disease in America: Cancer (New York: Facts On File, 1987), pp. 52, 100;

H. B. Williams, "Willem Einthoven," Science, 67 (4 May 1928): 456-457.

Berger, Hans

(b. Neuses bei Coburg, Germany, 21 May 1873; d. Jena, Germany, 1 June 1941)

psychiatry, electroencephalography.

The son of Paul Friedrich Berger and of Anna Rückert, Berger graduated from the Gymnasium at Coburg and then entered the University of Jena in 1892. After one semester in astronomy he transferred to medicine. In 1897 he became assistant to Otto Binswanger at the university’s psychiatric clinic. He was appointed chief doctor in 1912 and director and professor of psychiatry in 1919; he retired in 1938. His associates described Berger as punctual, strict, demanding, and reserved.

The central theme in Berger’s work was the search for the correlation between objective activity of the brain and subjective psychic phenomena. In his work on blood circulation in the brain (1901) he described his efforts to gain insight into this correlation through plethysmographic registration of the brain pulsations. He investigated the influence of the heartbeat, respiration, vasomotor functions, and position of the head and body on brain pulsations, which were measured through an opening, made by trephination, in the skull. Berger also studied the effects of a number of medications—such as camphor, digitoxin, caffeine, cocaine, and morphine—on brain pulsations. The results of these investigations were disappointing, yet Berger continued his search for measurable expressions of psychic conditions through experiments on blood circulation (1904, 1907).

After 1907 Berger tried to discover a correlation between the temperature of the brain and psychic processes. He postulated that through dissimilation in the cortex, psychic energy (P-Energie) develops, along with heat, electrical energy, and neural energy. These experiments also came to a dead end, according to Berger’s publication of 1910. Nevertheless, in his lectures on psychophysiology, given from 1905 on and published in 1921, the problem of P-Energie Continued to hold his interest. His tenaciousness in this matter is apparent from a memo in his journal dated 14 December 1921, in which he says that the goal of his research continues to be the correlation between the expressions of the human mind and the processes of dissimilation the in brain.

After his disappointing experiments measuring the blood circulation and temperature of the brain, Berger (following his return from World War I) devoted himself mainly to the measurement of the brain’s electrical activity. In 1902 he had taken measurements of electrical activity above skull defects with the Lippmann capillary electrometer, and later with the Edelmann galvanometer. In 1910, however, Berger mentioned in his journal that the results of these measurements were not satisfactory. Therefore, until 1925 he followed two methods of research: stimulation of the motor cortex through a defect in the skull, measuring the time between stimulus and contralateral motor reaction, and registration of the spontaneous potential differences of the brain surface. After 1925 Berger no longer used the stimulation method. He specialized, with ever increasing skill, in registering the spontaneous fluctuations in electrical potential that could be recorded through the skull from the cortex. In his first publication on electro-encephalography (1929), he called 6 July 1924 the date of discovery of the human electroencephalogram. The EEG, the curves of the electrical potentials measured again and again between two points of the skull, did not give him a closer insight into the correlation between the electrical activity of the brain and psychic energy. However, electroencephalography has proved to be of ever increasing importance in diagnosing and treating neurological diseases (epilepsy, brain tumors, traumata).

Berger’s work was strongly influenced by the exact psychology of the nineteenth century. In developing his psychophysiology, Berger used the ideas of J. F. Herbart, R. H. Lotze, G. T. Fechner, W. Wundt, and the Danish psychologist A. Lehmann as a base. In the experimental field, Berger was in all aspects a follower of A. Mosso. Berger’s experiments on brain circulation and brain temperature were identical with Mosso’s, and his publications on these subjects bore the same titles as Mosso’s papers.

In developing electroencephalography, Berger was influenced by Caton and by Nemminski. Caton had measured electrical potentials on the exposed cortex of experimental animals in 1875, but he was not able to record these phenomena graphically. Nemminski recorded the first electrocerebrogram on dogs with the skull intact by means of the Einthoven string galvanometer in 1913.

Berger’s historical significance lies in his discovery of the electroencephalogram of man. Although he began publishing his many papers on electroencephalography in 1929, he did not receive international recognition until Adrian and Matthews drew attention to his work in 1934.

BIBLIOGRAPHY

I. Original Works. Berger’s writings include Zur Lehre von der Blutzirkulation in der Schädelhöhle des Menschen nametlich unter dem Einfluss von Medikamenten (Jena, 1901); Ueber die körperlichen; Äusserungen psychischer Zustände, 2 vols. (Jena, 1904–1907); Untersuchungen überdie Temperatur des Gehirns (Jena, 1910); Hirn und Seele (Jena, 1919); Psychophysiologie in 12 Vorlesungen (Jena, 1921); Ueber die Lokalisation im Grosshirn (Jena, 1927); “Ueber das Elektrenkephalogramm des, Menschen,” in Archiv für Psychiatrie, 87 (1929), 527–570; 94 (1931), 16–60; 97 (1932), 6–26; 98 (1933). 231–254; 99 (1933), 555–574; 100 (1933), 301–320; 101 (1934), 452–469; 102 (1934), 538–557; 103 (1935), 444–454; 104 (1936), 678–689; 106 (1937), 165–187, 577–584; 108 (1938), 407–431; and Psyche (Jena, 1940).

II. Secondary Literature. Works on Berger are E. Adrian and B. Matthews. “The Berger Rhythm,” in Brain, 57 (1934), 355–385; Mary A. B. Brazier, “The Historical Development of Neurophysiology,” in Handbook of Physiology, I (Washington. D. C., 1959), 1–58, R. Caton, “The Electric Currents of the Brain,” in British Medical Journal (1875), ii , 278; H. Fischgold, “Hans Berger et sontemps;” in Actualitiés neurophysiologiques, 4th ser. (1962), 197–221; R. Jung, “Hans Berger und die Etdrckung des EEG nach seinen Tagebüchern und Protokollen,” in Jenenser EEG-Symposion (Jena, 1963), pp.” 20–53; K. Kolle, “Hans Berger.” in Grosse Nervenärzte, I (Stuttgart, 1956), 1–16; A. Mosso, Ueber den Kreislauf des Blutes im mensclihen Gehirn (Leipzig, 1881), pp. 104–197; and Die Temperatur des Gehirns (Leipzig, 1894), pp. 120–135; and W. Nemminski, “Ein Versuch der Registrierung derelektrischen Gehirnerscheichungen,” in Zentralblatt für Physiologie, 27 (1913), 951–960.

B. P. M. Schulte