Errors arise not only from scarcity but from excess of information, especially in transmuted form. Dramatic advances in recording techniques, computing, and visual display allow the topographic quantification of the whole spectrum of frequencies of brain activity and many other features. The potential exists for objective classification of physiologic brain patterns, early detection of pathologic processes, and more accurate mapping of epileptic activity. And yet, every algorithm is a compromise, making assumptions that may distort the information from atypical cases. Both Dr Duffy and Dr Nuwer warn against artifacts—old artifacts in new shapes and new artifacts created by processing and computing. Dr Nuwer is also concerned that epileptic spikes are generally overlooked or considered artifactual, that transient slowing can be missed or washed out, and that unusual normal variants may be interpreted as abnormal.
Dr Duffy states that quantitative neurophysiologic studies should never be "diagnostic," and he and Dr Nuwer