Hans Berger (21 May 1873 – 1 June 1941) was a German psychiatrist. He is best known as the inventor of electroencephalography (EEG) in 1924, which is a method used for recording the electrical activity of the brain, commonly described in terms of brainwaves, and as the discoverer of the alpha wave rhythm which is a type of brainwave. Alpha waves have been eponymously referred to as the "Berger wave." Biography Berger was born in Neuses (now part of Coburg), Saxe-Coburg and Gotha, Germany. After attending Casimirianum, where he gained his abitur in 1892, Berger enrolled as a mathematics student at the Friedrich Schiller University of Jena with the intention of becoming an astronomer. After one semester, he abandoned his studies and enlisted for a year of service in the cavalry. During a training exercise, his horse suddenly reared, and he landed in the path of a horse-drawn cannon. The driver of the artillery battery halted the horses in time, leaving the young Berger shaken but with no serious injuries. His sister, at home many kilometres away, had a feeling he was in danger and insisted their father telegram him. The incident made such an impression on Berger that, years later in 1940, he wrote: "It was a case of spontaneous telepathy in which at a time of mortal danger, and as I contemplated certain death, I transmitted my thoughts, while my sister, who was particularly close to me, acted as the receiver." On completion of his military service, and obsessed by the idea of how his mind could have carried a signal to his sister, Berger returned to Jena to study medicine with the goal of discovering the physiological basis of "psychic energy." His central theme became "the search for the correlation between objective activity in the brain and subjective psychic phenomena." After obtaining his medical degree from Jena in 1897, Berger joined the staff of Otto Ludwig Binswanger (1852–1929), who held the chair in psychiatry and neurology at the Jena clinic. Habilitated in 1901, he qualified as a senior university lecturer in 1906 and physician-in-chief in 1912, eventually succeeding Binswanger in 1919. He also collaborated with two famous scientists and physicians, Oskar Vogt (1870–1959) and Korbinian Brodmann (1868–1918), in their research on lateralization of brain function. Berger married his technical assistant, Baroness Ursula von Bülow, in 1911 and later served as an army psychiatrist on the Western front