血液透析患者の聴覚性誘発電位(AEP)と脳波

AEP (Auditory Evoked Potential) and EEG were studied with 20 patients undergoing hemodialysis (dialyzed group, 41~65 y. o.), consisted of non-diabetic group (13 with chronic glomerulonephritis) and diabetic group (7 with diabetic nephropathy), comparing with those of 20 healthy subjects (normal group, 38~66 y. o.). EEGs containing AEPs evoked by click stimulation were recorded with 1024 msec of analysis time through the two derivations (3 CH : Cz→A1+2 and 6CH : Cz→T5). The group-mean AEPs were obtained with each group, and compared with each other, and then the differences of latencies and peak-to-peak amplitudes of the components were tested statistically between the groups.
The EEGs were subjected to the quantitative frequency analysis. Correlation coefficients were tested statistically between the latencies, peak-to-peak amplitudes of AEP components and EEG power %, and between those and blood data. The following results were obtained.
1. The waveforms of group-mean AEP of normal group had hexaphasic contour, consisted of components P1~8 and N1~8, including the prominent negative peak N4 and positive peak P5, within 600 msec of latency.
2. The group-mean AEP of non-diabetic group had similar contour to that of normal group. Latencies of the components were significantly longer except for that of P5, and peak-to-peak amplitudes were mostly larger, than those of normal group.
3. The group-mean AEP of diabetic group had also similar contour to that of normal group, but the prominent negative peak was N3. Latencies of the components were significantly longer except for that of P5, and peak-to-peak amplitudes were smaller, than those of normal group.
4. The latencies of the diabetic group were significantly shorter, and the peak-to-peak amplitudes were also smaller, than those of non-diabetic group.
5. Quantitative frequency analysis of EEG resulted in significant decrease of α2 power% and increase of β1 power % in non-diabetic group, and significant decrease of β1 power % in diabetic group.
6. Positive correlation was found between δ power % of EEG and the latencies of long-latency components of AEP, and negative correlation between α1, α2, β2 power % and the latencies of middle-long-latency components. Between peak-to-peak amplitudes of AEP, negative correlation was found with δ power %, and positive correlation with β1 power %.
7. Between AEP-latencies, the positive correlation was found with Cr (creatinine) and K (potassium), negative correlation with P (phosphorus). Between AEP-amplitudes, positive correlation was found with BUN and P, and negative correlation with Cr and calcium.
These results were considered to be attributed to the more prominent inhibition of GABA-inhibitory system in gray matter in non-diabetics, and to severe disturbances in both white and gray matter in diabetics, reflecting antagonistic influences from pathological condition between non-diabetics (uremia) and diabetic nephropathy.