Most researchers agree that the CNV component has been associated with information processing and response preparation. The main controversy is whether the CNV is composed of more than one component. After discovery of the CNV, researchers were able to distinguish between two main components of the CNV. Loveless and Sanford (1975) and Weerts and Lang (1973) increased the interstimulus interval to greater than 3 seconds and showed that two components can be visually distinguished from the CNV. The first wave followed the warning stimulus and was called the O wave, or orienting wave. This wave showed enhanced amplitude in the frontal regions. The second wave preceded the imperative stimulus and was called the E wave, or expectancy wave. A study conducted by Gaillard (1976) provided further evidence that the O wave was frontally distributed and was more strongly affected by auditory stimuli rather than visual stimuli.
