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Photically driven EEGs were recorded from patients with renal disease using photic stimulation at integer rates between 3 and 12 flashes/sec. Changes in the structure of the power spectrum of the potentials produced by this stimulus paradigm are described as a function of a patient's clinical state. The basic overall findings are that (1) harmonic activity is attenuated while activity below the fundamental driving frequency is increased as a patient's clinical condition deteriorates, and (2) that these effects are substantially reversed and controlled by means of dialysis and renal transplantation.

Transient visually evoked cortical potentials (VECPs) were recorded from patients with renal disease. Changes in VECP latencies are described for undialyzed patients, patients receiving dialysis therapy, and patients who received kidney transplants. Characteristics of VECP latencies in these patient groups as well as examples of changes in latency values with respect to time for two individual patients are examined. The basic overall finding is that the VECP latencies increase as a patient's clinical condition deteriorates and normalize as the condition improves.

EEGs wre recorded from renal patients to determine if there are quantifiable characteristic changes in the EEG was quantified by calculating the percentage of spectral power in the bandwidth 3-7 c/sec referrred to a frequency range of 3-13 c/sec and by computing the mean frequency of the dominant rhythm in the EEG. Blood urea nitrogen and creatinine concentrations, as well as a self-assessment of the patient's clinical condition, were recorded. The general finding of this research is that EEG slowing, as evaluated by power spectral techniques, is correlated with uremia-associated variables. 1. In a non-dialyzed patient population with renal failure, slowing in the EEG was found to be directly corelated with increased creatinine concentrations. 2. Quantitative measures of slow wave activity computed using power spectral techniques were found to be highly corelated with an estimate of slowing made by an electroencephalographer. 3. Compared with undialyzed azotemic patients, malignant hypertensive patients with comparable serum creatinine concentrations typically displayed increased slow wave activity, while slowing was generally reduced in the dialyzed patient population. 4. A series of EEGs recorded from one patient during the first three dialyses of her life revealed that slow wave activity decreased during each successive dialysis. In another patient, all quantified EEG values recorded prior to renal transplantation significantly improved after transplantation...