 His early research with Hans Helmut Kornhuber in the mid-1960s led to the discovery of the Bereitschaftspotential (or readiness potential), which is a measure of neural activity in the brain that precedes voluntary movements.This discovery set an important standard in research and rehabilitation of motor systems, and re-introduced the word will in key word registers.In 1964 Deecke performed as doctoral student of Hans Helmut Kornhuber, EEG-recordings in man accompanying volitional movements and actions, and they discovered a slowly increasing activation (negative deflection) in the EEG, which they called "Bereitschaftspotential"

The term Bereitschaftspotential (BP) can be found in the ‘List of German expressions in English‘.