Dichotic listening in patients with partial section of the corpus callosum.
Dichotic listening in patients with partial section of the corpus callosum.
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胼胝体部分切片患者的双耳听力。
DOI：
10.1093/brain/118.2.417
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
A. Shinohara
中科院分区：
文献类型：
--
作者：
M. Sugishita;K. Otomo;K. Yamazaki;H. Shimizu;M. Yoshioka;A. Shinohara
已经观察到具有完整胼胝体部分的患者在同时向双耳呈现不同的语音刺激时表现出强烈的左耳抑制（所谓的双耳分听）。关于胼胝体损伤导致左耳强抑制的部位的数据仍然很少。在本调查中，辅音-元音音节两分听测试给予5个右利手的患者胼胝体，这是使用MRI和准确定义的测量程序的部分。采用以下两种测量方法：（i）胼胝体压部（G-S）法，其中病变位于相对于胼胝体总长度的前后方向，定义为胼胝体最前点到压部最后点之间的距离;以及（ii）喙部压部（R-S）方法，其考虑了胼胝体的曲率，并且其中相对于胼胝体的总长度定位损伤，定义为从喙尖到压部末端的曲线的长度。结果与50名正常对照组进行比较。在两名患者中观察到强烈的左耳抑制，他们手术切除了胼胝体后部15.5-18.5%（用G-S方法测量）或胼胝体后部20-24%（用R-S方法测量）。这种抑制现象在术后持续了10年以上。另一方面，其余3名患者，其胼胝体前部病变占胼胝体后部的17-28%（用G-S法测量）或20-33%（用R-S法测量），未表现出左耳消退。尽管通常假设胼胝体躯干后部的损伤会引起强烈的左耳抑制，但G-S方法的结果表明，压部（定义为胼胝体最前点和最后点之间的后五分之一节段）的损伤会引起强烈的左耳抑制。通过R-S方法，结果表明，压部（胼胝体曲率的后五分之一）和可能延伸到躯干最后部分（曲率的后四分之一）的部分的损伤引起强烈的左耳抑制。
Patients with a complete section of the corpus callosum have been observed to exhibit strong left-ear suppression when different speech stimuli are presented to both ears simultaneously (so-called dichotic listening). Data concerning the locus of corpus callosum damage that causes strong left-ear suppression remains scanty. In the present investigation, a consonant-vowel syllable dichotic listening test was given to five right-handed patients with partial sections of the corpus callosum, which were located using MRI and accurately defined measurement procedures. The following two measurement methods were used: (i) the genu-splenium (G-S) method, in which a lesion was localized in the anteroposterior dimension relative to the total length of the corpus callosum, defined as the distance between the most anterior point of the genu to the most posterior point of the splenium; and (ii) the rostrum-splenium (R-S) method, which takes into account the curvature of the corpus callosum, and in which a lesion was localized relative to the total length of the corpus callosum, defined as the length of the curved line from the tip of the rostrum to the end of the splenium. Results were compared with scores from 50 normal control subjects. Strong left-ear suppression was observed in two patients, who had surgical sections of the posterior 15.5-18.5% of the corpus callosum as measured with the G-S method, or the posterior 20-24% of the corpus callosum as measured with the R-S method. The suppression phenomenon persisted for more than 10 years post-surgery. On the other hand, the remaining three patients, who had lesions anterior to the posterior 17-28% of the corpus callosum as measured with the G-S method or 20-33% as measured with the R-S method exhibited no left-ear extinction. Despite the common assumption that damage to the posterior part of the trunk of the corpus callosum causes strong left-ear suppression, the results from the G-S method indicated that damage to the splenium defined as the posterior one-fifth of the segment between the anterior-most and posterior-most points of the corpus callosum, cause strong left-ear suppression. By the R-S method, results showed that damage to the splenium (the posterior one-fifth of the curvature of the corpus callosum) and possibly the part extending to the most posterior part of the trunk (the posterior one-quarter of the curvature) causes strong left-ear suppression.