Brown W S, Bjerke M D, Galbraith G C
The Travis Institute for Biopsychosocial Research, Fuller Graduate School of Psychology, Dept. of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, USA.
Cortex. 1998 Dec;34(5):677-92. doi: 10.1016/s0010-9452(08)70772-x.
Interhemispheric transfer time (IHTT) can be estimated from visual evoked potentials (EPs). Latency adjusted averaging (LAA) produces EPs which have enhanced components. LAA also provides estimates of EP latency variance and signal-to-noise ratio (S/N). LAA was tested in analysis of EP-IHTT in normal and acallosal subjects. It was hypothesized that in normals S/N and latency variance would reveal signal degradation resulting from interhemispheric transfer. LAA in normals replicated IHTT findings for both P1 and N1 latency. Latency variance did not increase for cross-callosal measures, whereas the S/N measure showed significant EP degradation due to callosal transfer. EPs from five subjects with callosal absence (two commissurotomy; two complete and one partial callosal agenesis) showed significantly larger than normal latency variability, as well as decreased S/N ratios, for cross-hemisphere visual EPs. Results support the value of LAA in EP research on adequacy of hemispheric interactions in clinical populations.
半球间传递时间（IHTT）可通过视觉诱发电位（EP）进行估算。潜伏期调整平均法（LAA）可产生具有增强成分的诱发电位。LAA还可提供诱发电位潜伏期方差和信噪比（S/N）的估计值。在正常人和胼胝体缺失者的EP-IHTT分析中对LAA进行了测试。假设在正常人中，信噪比和潜伏期方差将揭示半球间传递导致的信号退化。正常人的LAA复制了P1和N1潜伏期的IHTT结果。胼胝体交叉测量的潜伏期方差没有增加，而信噪比测量显示由于胼胝体传递导致诱发电位显著退化。五名胼胝体缺失患者（两名连合部切开术；两名完全性和一名部分性胼胝体发育不全）的跨半球视觉诱发电位显示，潜伏期变异性明显大于正常，信噪比降低。结果支持LAA在临床人群半球间相互作用充分性的诱发电位研究中的价值。
