Electroencephalographic and other neurophysiological abnormalities in uremia.

1) Neurophysiological abnormalities in patients with renal failure are being investigated because a) it is the nervous system which preeminently produces the phenomena of clinical uremia that dialysis affects and b) objective quantitative measures of such functions are generally lacking and are needed to provide objective evidence for adequacy of dialysis and other treatment measures in uremic patients. Accordingly, the attempt is warranted to measure in objective terms what renal failure, alternatively maintenance dialysis, does to the patient's nervous system in the comprehensive terms and the several modalities by which the nervous system serves the patient. 2) It is clear from the foregoing presentation that electroencephalographic phenomena including some aspects of the spontaneous EEG and certain event-related potentials can be readily reduced to quantitative terms. Some of these are abnormal in the presence of renal failure, are improved by dialysis treatment, may vary with the frequency of dialysis treatment and are often normalized by renal transplantation. Apparently similar EEG changes may be induced by other intercurrent influences occasionally operating in patients with renal failure. These can usually be readily detected but appear at this time to limit the potential usefulness of the EEG in those instances. However, especially using successive determinations in individual patients, the quantitative measure of slow-wave-associated EEG power is a reasonable candidate-measure of adequacy of dialysis. Other measures should be explored. 3) Quantitative measures of EEG phenomena appear to be superior in speed and objectivity to conventional, descriptive reporting of electroencephalograms, especially for the repetitive comparisons which are necessary for clinical patient monitoring. 4) The data system so far employed to transform EEG phenomena into clinically useful data (Fig. 1) will be greatly simplified as soon as the most informative, sensitive and specific measures are selected from among those being explored. Dedicated micro-processing equipment, for example, can then be expected to replace the much more expensive, multipurpose computer system which is necessary for the initial investigation.