Recording the brain at work: the visible, the readable, and the invisible in electroencephalography

The electroencephalogram (EEG), the graphic recording of the electric activity of the human brain, kindled far-reaching speculations about the imminent deciphering of mind and brain in the 1930s. Regardless of the thousands of neurons in the human cortex, recording from a person at rest produced a surprisingly regular line oscillating at 10 per second that disappeared at the moment of mental activity. With ever more groups specializing in electroencephalography, however, the deciphering of mind and brain did not materialize but moved further away in the information produced. In the various approaches employed in EEG research, such as the analysis of the graphic code, the search for pathognomic patterns or the imaging of cognitive processing, visualization guided research as well as theorizing, its productivity continued to keep the epistemological question open.

Ellen R. Grass lecture: present at the beginning. Ellen Grass and the evolution of modern concepts regarding EEG and epilepsy

Ellen Grass was a remarkable woman whose efforts on behalf of neurophysiology, epilepsy, and physiological technology contributed importantly to the development of neuroscience in the United States during the middle third of the 20th century. She initially provided an important link between a remarkable group of Harvard physiologists and her husband, Albert, a brilliant engineer whose innovative equipment played a critical role in accelerating advances in neurophysiology and, later, EEG and epilepsy. Mrs. Grass herself observed and personally facilitated much of the clinical and basic neuroscience research during this period, when the modern framework for a scientific understanding of epilepsy and EEG was established. She also supported the development of professional societies relevant to these areas, including ASET, the American EEG Society, the American Epilepsy Society, and the Epilepsy Foundation of America.

From lateral to mesial: the quest for a surgical cure for temporal lobe epilepsy

PURPOSE

A gap of more than a hundred years occurred between the first accounts of mesial temporal sclerosis and recognition of its role in the pathogenesis of psychomotor seizures. This paper reviews how the understanding and surgical treatment of temporal lobe epilepsy developed, particularly from the work of Penfield, Jasper, and their associates at the Montreal Neurological Institute (MNI).

METHODS

Publications on EEG and surgery for temporal lobe seizures from 1935 to 1953 were reviewed and charts of selected patients operated on at the MNI in the same period were examined. Attention was focused on the evolution of surgical techniques for temporal lobe epilepsy.

RESULTS

In the late 1930s, some EEG findings suggested deep-lying disturbances originating in the temporal lobe. However, it took another two decades before the correlation of clinical, neurophysiological, and anatomical findings provided evidence for the involvement of the mesial structures in psychomotor or temporal lobe seizures. From 1949 and onward, Penfield and his associates applied this evidence to extend the surgical resections to include the uncus and the hippocampus.

CONCLUSION

The collaborative work of a team led by Penfield and Jasper at the MNI helped to define the role of neurophysiological studies in epilepsy surgery. As a result, the importance of removing the mesial structures in order to obtain better seizure control in patients with temporal lobe epilepsy became firmly established.

The concept of brain death did not evolve to benefit organ transplants

Although it is commonly believed that the concept of brain death (BD) was developed to benefit organ transplants, it evolved independently. Transplantation owed its development to advances in surgery and immunosuppressive treatment; BD owed its origin to the development of intensive care. The first autotransplant was achieved in the early 1900s, when studies of increased intracranial pressure causing respiratory arrest with preserved heartbeat were reported. Between 1902 and 1950, the BD concept was supported by the discovery of EEG, Crile's definition of death, the use of EEG to demonstrate abolition of brain potentials after ischaemia, and Crafoord's statement that death was due to cessation of blood flow. Transplantation saw the first xenotransplant in humans and the first unsuccessful kidney transplant from a cadaver. In the 1950s, circulatory arrest in coma was identified by angiography, and the death of the nervous system and coma dépassé were described. Murray performed the first successful kidney transplant. In the 1960s, the BD concept and organ transplants were instantly linked when the first kidney transplant using a brain-dead donor was performed; Schwab proposed to use EEG in BD; the Harvard Committee report and the Sydney Declaration appeared; the first successful kidney, lung and pancreas transplants using cadaveric (not brain-dead) donors were achieved; Barnard performed the first human heart transplant. This historical review demonstrates that the BD concept and organ transplantation arose separately and advanced in parallel, and only began to progress together in the late 1960s. Therefore, the BD concept did not evolve to benefit transplantation.

State-of-the-Art of Seizure Prediction

SUMMARY

Although there are numerous studies exploring basic neuronal mechanisms that are likely to be associated with seizures, to date no definite information is available as to how, when, or why a seizure occurs in humans. The fact that seizures occur without warning in the majority of cases is one of the most disabling aspects of epilepsy. If it were possible to identify preictal precursors from the EEG of epilepsy patients, therapeutic possibilities and quality of life could improve dramatically. The last three decades have witnessed a rapid increase in the development of new EEG analysis techniques that appear to be capable of defining seizure precursors. Since the 1970s, studies on seizure prediction have advanced from preliminary descriptions of preictal phenomena and proof of principle studies via controlled studies to studies on continuous multiday recordings. At present, it is unclear whether prospective algorithms can predict seizures. If prediction algorithms are to be used in invasive seizure intervention techniques in humans, they must be proven to perform considerably better than a random predictor. The authors present an overview of the field of seizure prediction, its history, accomplishments, recent controversies, and potential for future development.

The concept of the epileptogenic zone: a modern look at Penfield and Jasper's views on the role of interictal spikes

In modern times, the determination of the epileptogenic zone demands a sophisticated combination of neurophysiological and neuroimaging tools. Historically however, the concept of the epileptogenic zone was based on and has evolved from the recording of interictal spikes, both in the scalp electroencephalogram (EEG) and, particularly, in the acute electrocorticogram (ECoG). Because the role of interictal spikes is still not always clear in the decision-making process of epilepsy surgery, the relevance of these spikes in the definition of the epileptogenic zone is reviewed here, starting with the pioneering work of the Montreal school.

Between local cultures and national styles: units of analysis in the history of electroencephalography

The history of the discovery of the human electroencephalogram (EEG) and the ensuing implementation of electroencephalography is characterized by striking national differences. The first publication on the EEG in 1929 by the German psychiatrist Hans Berger was met with skepticism. Substantial work in this area did not start before the public demonstration of the EEG by the British neurophysiologist Edgar Douglas Adrian in 1934. Soon afterwards, many groups specialized in the new method, particularly in the US, whereas interest remained more limited in France and Britain. A comparative analysis of the rise of electroencephalography has certainly to account for such national differences, but the trajectory of the implementation of this technology calls for an investigation of local research cultures in order to identify units of productivity and to understand the dynamics along this trajectory.

W. Grey Walter, pioneer in the electroencephalogram, robotics, cybernetics, artificial intelligence

With the announcement by William Lennox at the 1935 London International Neurology Congress of the use of electroencephalography in the study of epilepsy, it became evident that a new and powerful technique for the investigation of seizures had been discovered. William Grey Walter, a young researcher finishing his post-graduate studies at Cambridge, was selected to construct and study the EEG in clinical neurology at the Maudsley Hospital, London. His hugely productive pioneering career in the use of EEG would eventually lead to groundbreaking work in other fields --the emerging sciences of robotics, cybernetics, and early work in artificial intelligence. In this historical note his pioneering work in the fields of clinical neurophysiology is documented, both in the areas of epileptology and tumour detection. His landmark contributions to clinical neurophysiology are worthy of documentation.

Richard Caton (1842-1926): pioneer electrophysiologist and cardiologist

Richard Caton is recognized as the discoverer of the waves of electrical potential which today form the basis of electroencephalography. He reported his finding in three communications, two in the British Medical Journal and one to the Ninth International Congress of Medicine at Washington, DC. After defending his priority in having made this discovery, he did no further work on the brain: his family and colleagues were unaware of his discovery for many years after his death. This was possible partly because of many other things that he did in his long life but also because, in his later years, he took deliberate steps to hide the fact that he had worked on the brain. The most important of these other activities was a practical study of the treatment of rheumatic heart disease. The basis of his treatment--complete rest in bed--is still in use today.

The epileptology of William Aldren Turner

William Aldren Turner (1864-1945), in his day Physician to the National Hospital, Queen Square, and to King's College Hospital, London, was one of the major figures in the world of epileptology in the period between Hughlings Jackson in the latter part of the 19th century and the advent of electroencephalography in the 1930s. Although he also made contributions to knowledge in other areas of neurology, and with Grainger Stewart wrote a competent textbook on that subject, Turner's main professional interest throughout his career seems to have been epilepsy. On the basis of a series of earlier, rather heavily statistical, personal publications dealing with various aspects of the disorder, he authored what became a well-accepted monograph entitled Epilepsy - a study of the idiopathic disorder, which appeared in 1907, and he also gave the 1910 Morison lectures in Edinburgh on the topic. His writings on epilepsy over a period of three decades consolidated knowledge rather than led to significant advances, but helped maintain interest in the disorder during a rather long fallow phase in the development of the understanding of its nature.

The First Case of Invasive EEG Monitoring for the Surgical Treatment of Epilepsy: Historical Significance and Context

PURPOSE

Controversy persists about when EEG became a fundamental tool in the preoperative investigation for epilepsy surgery. We revisit Penfield's first use of invasive EEG monitoring, emphasizing its historical importance for the evolution of epilepsy surgery.

METHODS

Patients' hospital charts and articles published before 1940 regarding EEG and epilepsy or EEG and cerebral lesions were reviewed to evaluate the historical context of the surgery.

RESULTS

In April 1939, Penfield performed trephination over both temporal regions and placed electrodes on the dura, intending to lateralize seizure origin in a patient with bitemporal epilepsy. The patient underwent serial EEGs with this technique. The final report of the recordings from epidural leads was "continued random delta activity in the left temporal region indicating a cortical lesion on this side." The pneumoencephalogram showed "the presence of diffuse cerebral atrophy, particularly in the left cerebral hemisphere." Based on these findings, the patient underwent surgery on April 21, revealing a meningocerebral scar in the posterior part of the left temporal lobe. Brain stimulation and electrocorticography delineated the extent of resection, while preserving the speech area. Seizures did not improve.

CONCLUSIONS

We revisit the first case of epidural EEG monitoring for epilepsy surgery and show that the concept of EEG-directed surgery was already present at the Montreal Neurological Institute in the late 1930s.

["If Berger had survived the second world war - he certainly would have been a candidate for the Nobel Prize". Hans Berger and the legend of the Nobel Prize]

The public opinion pays much attention to the Nobel Prize as an indicator for the scientific efficiency of a university or a country in connection with foundation of so-called elite universities. The former holder of the psychiatric chair in Jena and discoverer of the electroencephalogram Hans Berger (1873 - 1941) came into discussion as candidate for the Nobel Prize in physiology or medicine. The current medical-historical publications maintain the view that Berger should have received the Nobel Prize in 1936 as well as in 1949. This was prevented in 1936 by an enactment from Hitler, which forbid him to accept the prize, and later in 1949 by Berger's own death. According to documents of the Nobel archives these statements can be disproved. Berger was only nominated three times out of 65 nominations in 1940. Because of his death the other two recommendations in 1942 and 1947 were never evaluated.