Quantitative EEG findings in patients with chronic renal failure.

OBJECTIVE Chronic renal failure frequently causes uremic encephalopathy with impairment of various cognitive functions, but the pathophysiology of uremic syndrome is complex and poorly understood. In this study, we wished to establish a reliable tool and monitor system to evaluate the central nervous system dysfunction of patients with uremic encephalopathy. METHODS A group of 31 patients with chronic renal failure was assessed with online real time brain mapping using the CATEEM technology to detect deviations and abnormal EEG patterns. Quantitative EEG data were compared with those of an age-matched healthy control group and correlated to laboratory markers and various dosages of erythropoietin. RESULTS Electrical power was most prominent in delta, theta and alpha frequencies in the temporal and central brain areas (electrode positions T5, T6, C3 and C4). Explorative statistical comparison of the two data sets with respect to these brain areas revealed that the increases in electrical power in delta, theta and alpha frequency bands were different from healthy people with p-values of p<0.003 (delta), p<0.0003 (theta), p<0.01 (alpha 1) and p<0.01 (alpha 2). In addition, high levels of hemoglobin were significantly correlated with higher theta activity. CONCLUSION We detected distinct EEG deviations from normality in patients with chronic renal failure. Online real time brain mapping using the CATEEM technology provides a unique possibility to monitor mental impairment and serves as a control for therapeutical intervention.