2002 Volume 39 Issue 10 Pages 634-641
Richard Caton was the first to report the electrical activity from brain in animal, in as early as 1875. However, it took more than 50 yeas, when Hans Berger successfully recorded electrical activity from the human brain using surface scalp electrodes in 1929. In 1935, Gibbs, Davis and Lennox discovered the 3Hz spike-wave bursts in association with absence (petit mal) seizure, and in 1936 focal spike in epilepsy was found by Jasper and focal slowing was noted in brain tumor by Walter. Since, the EEG has brought tremendous contributions to the fields of clinical neurology and neurophysiology. As a clinical diagnostic tool, the EEG has provided information for functional as well as anatomical (structural) brain disturbances. As a functional diagnosis, the EEG is superior to other function tests such as PET, SPECT or functional MRI because of its excellent temporal resolution representing moment to moment changes in the level of consciousness. However, the progress has been hampered due to difficulty in quantifying EEG data because of its extreme dynamics and variability, which perhaps reflects complex yet unknown brain functions. This difficulty will be overcome by improved quantification methods and statistical measures using various computer applications including topographic mapping, power spectrum analysis, covariance, and correlation or coherence function. By solving these problems, EEG will become important tool for understanding the functional anatomy of brain and will fulfill Berger's dream, “EEG is a window of human mind”.
