We report a method of quantifying the analog signal of paper-recorded EEGs that involves readily available technology, including a standard personal computer and a compatible hand scanner. Simulations assessed the effects of erroneously scanning the paper at a slight angle and estimating pen arc distortion; these effects were demonstrated to be insignificant. The method allows application of several quantitative techniques, including power spectral analysis and determination of the squared coherence between homologous regions. In a companion study, we applied this technique to compare the coherence in patients with alpha pattern coma to coherence in normal subjects.
Department of Clinical Neurological Sciences, University of Western Ontario, London, Ontario, Canada
Dr. McKeown's present address is Computational Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd., La Jolla, CA 92037, U.S.A.
Address correspondence and reprint requests to Dr. G. B. Young at Department of Clinical Neurological Sciences, Victoria Hospital, 375 South St., London, Ontario N6A 4G5, Canada.