Abstract
The purpose of this study was to clarify the effects of chronic hemodialysis on cerebral neurocognitive function by studying P300.
Ten chronic hemodialysis patients (3 males and 7 females, of mean age=44.1±8.1 years, range=30-55 years) were investigated. The duration of hemodialysis, which was performed three times a week ranged from 9 to 15 years (mean=10.7±1.8). As controls, 30 normal subjects (14 males and 16 females, of mean age=47.7±19.0 years, range=22-105 years) were entered into this study.
An auditory oddball paradigm was used in which subjects counted low-probability, higher pitch, target tone-bursts (2000Hz, 20% trials) occurring randomly among more frequent, lower pitch, non-target tone-bursts (1000Hz, 80%). Two hundred tone-bursts were given. Electroencephalogram (EEG) electrodes were affixed to the scalp at Fz, Cz and Pz, and recorded against a linked earlobe reference (1-30Hz bandpass). To check artifacts, electrooculogram was recorded. EEG was analyzed from 100msec before the stimulus until 600msec after it. To confirm reproducibility, recordings were performed at least twice. P300 was defined as evoked potentials which had a positive peak between 250 and 500msec. The shortest peak latency of P300 was adopted.
In normal controls, the peak latencies of P300 increased in an orderly manner with age. The slope of the regression line was 2.23msec/year at Fz, 2.07msec/year at Cz and 1.97msec/year at Pz. The peak latencies of P300 in all hemodialysis patients ranged within normal limits.
Chronic (over nine years) hemodialysis patients have normal neurocognitive function as expressed by P300.
