Who recorded the first human electroencephalogram, or EEG?

Hans Berger recorded the first human electroencephalogram, or EEG.

Berger, a German psychiatrist, published his findings in 1929 after recording electrical activity from the human scalp. He identified rhythmic patterns, including the approximately 10-hertz rhythm later called the alpha wave, or Berger wave, when a person is relaxed with eyes closed.

An EEG measures voltage changes produced by synchronized electrical activity in the brain through electrodes placed on the scalp. It does not photograph individual neurons and does not directly read thoughts. Instead, it provides excellent timing information about broad patterns of brain activity.

EEG became useful in clinical neurology, especially for evaluating seizures and certain sleep patterns. Its historical development followed earlier animal experiments and advances in amplification and recording technology. Modern systems may use many electrodes, but the basic principle remains the measurement of electrical potential differences over time.