Nineteen-year-old Hans Berger falls from a rearing horse. A military vehicle almost crushes his skull.
Later that evening, Berger receives a telegram from his family. He finds this odd for two reasons:
1) He’d never received a single telegram from his family.
2) The telegram expressed concern; his family seemed to know something had happened even though they lived miles away.
Remembering how currents of fear flowed through him during the accident, Berger wonders if—by some mysterious brain mechanism—he had sent a “distress signal” to his family. Berger will spend the rest of his life looking for empircal evidence to explain the brain's abstract processes.
1892 - 1920, University of Jena, Germany
Berger craved more substance than brain theories could offer; he wanted to observe and measure actual brain activity, to see the mind in action. His experiments involved unorthodox apparatus and methods. (Picture a subject with a dish of water on his head. A wire connects him to a machine fixed with a set of metal symbols. Behind the subject’s unsuspecting back, Berger fires a pistol and listens as the clashing metal symbols record changes in the subject’s blood flow.)
Despite Berger’s creative techniques, he established only correlations between stimuli and energy output; he observed no imprints of brain activity.
1920 - 1940, University of Jena, Germany
Berger focused his attention on directly capturing electrical activity in the brain, or as he would say, “creating a brain mirror.” Having failed to collect electrical readings in the past, Berger committed to tweaking and adjusting his equipment—an electrometer, electrodes, and a string galvanometer—until he had tried every configuration and variation possible.
After weeks of modifications, Berger recorded the first electroencephalogram (EEG) readings. The lines, while faint, captured electrical oscillations—a measurable, scientific metric for studying brain activity.
Invigorated, Berger invested in new equipment, tested different configurations, and experimented on more subjects. In 1929, Berger published a paper on his findings, “On the Human Electroencephalogram (Uber das Elektrenkephalogramm des Menschen).”
Scientists, clinicians, and engineers around the world built on Berger’s invention, creating more accurate readings, finding clinical applications, and perfecting the instrumentation.
“Within 20 years of Berger’s first publication, EEG had become a formal laboratory or department in many institutions,” writes brain researcher Thomas F. Collura in a paper on the history and evolution of the EEG. “By the mid-1950s, nearly every teaching hospital was equipped for EEG. By 1960, systems were found in many other hospitals and in private practices.”
Present day, worldwide
During World War I, Berger kept a journal where he recorded ambitious hopes for his invention.
“Thinking about new paths in my scientific work. Go further along previous paths, but only those with some connection to [clinical] practice . . . i.e. Meaning of psychic origins for mental and other diseases (critical investigation!) . . .”
EEG fulfilled and surpassed Berger’s hopes.
The technology revolutionized neurological and psychiatric care. Real-time tracking of brain activity increased the precision and safety of brain surgery, and it also fortified the understanding and diagnosis of neurological disorders, including epilepsy and neurodegeneration. Researchers at UCLA now want to leverage EEG to establish biomarkers relevant to autism spectrum disorder (ASD).
"We should be able to use EEG to start understanding different processing patterns in high-risk infants and in children with autism across the spectrum,” says Shafali Spurling Jeste, MD. “If you can give a baby a task or show them pictures while recording EEG, you can get a readout of how the brain is processing information without having to ask the infant or child to provide an answer. You also can measure the way in which brain networks are connected and functioning. That's pretty powerful."