Table 1.
Gold Standard of the Classification in Visual Evoked Potential
| Visual Measurements |
No Change (n = 37) |
Increasing (n = 68) |
Decreasing (n = 47) |
P |
| Visual acuity, no. (%) | ||||
| Normal | 11 (29.7) | 33 (48.5) | 29 (61.7) | 0.003 |
| Abnormal | 26 (70.3) | 35 (51.5) | 18 (38.3) | |
| Visual field, no. (%) | ||||
| Normal | 15 (41.7) | 29 (42.6) | 21 (44.7) | 0.484 |
| Abnormal | 22 (58.3) | 39 (57.2) | 26 (55.3) | |
| Preanesthesia VEP, mean ± SD | ||||
| Amplitude (μv) | 4.4 ± 2.1 | 3.6 ± 2.1 | 4.2 ± 2.9 | 0.253 |
| Latency (ms) | 103.3 ± 28.4 | 97.2 ± 26.3 | 99.5 ± 27.9 | 0.586 |
| VEP after stable anesthesia (baseline) | ||||
| Amplitude (μv), mean ± SD | 2.2 ± 0.9 | 1.2 ± 0.7 | 1.5 ± 2.0 | 0.001 |
| Amplitude change from preanesthesia, (CI), % | −53 (−70, −20) | −67 (−79, −45) | −71 (−107, −21) | 0.037 |
| Latency (ms), mean ± SD | 112.8 ± 28.3 | 102.2 ± 28.7 | 102.0 ± 30.4 | 0.153 |
| Latency change from preanesthesia, (CI), % | 13 (−5, 31) | 8 (−23, 40) | 2 (−19, 32) | 0.892 |
| VEP during tumor decompression | ||||
| Amplitude (μv), mean ± SD | 2.1 ± 0.9 | 3.0 ± 1.9 | 1.4 ± 1.2 | <0.001 |
| Amplitude change from baseline, (CI), % | 0 (−10, 0) | 146 (69, 270) | −75 (−270, −43) | <0.001 |
| Latency (ms), mean ± SD | 99.1 ± 29.3 | 95.6 ± 27.1 | 100.6 ± 25.7 | 0.604 |
| Latency change from baseline, (CI), % | −5 (−17, 0) | −3 (−15, 5) | 0 (−12, 17) | 0.058 |
no., number; CI, 95% confidence interval.