Price C J, Howard D, Patterson K, Warburton E A, Friston K J, Frackowiak S J
Wellcome Institute of Neurology Department of Cognitive Neurology London UK 12 Queen Square WC1N 3BG, UK.
J Cogn Neurosci. 1998 May;10(3):303-15. doi: 10.1162/089892998562753.
Deep dyslexia is a striking reading disorder that results from left-hemisphere brain damage and is characterized by semantic errors in reading single words aloud (e.g., reading 'spirit' as 'whisky'). Two types of explanation for this syndrome have been advanced. One is that deep dyslexia results from a residual left-hemisphere reading system that has lost the ability to pronounce a printed word without reference to meaning. The second is that deep dyslexia reflects right-hemisphere word processing. Although previous attempts to adjudicate between these hypotheses have been inconclusive, the controversy can now be addressed by mapping functional anatomy. In this study, we demonstrate that reading by two deep dyslexic patients (CJ and JG) involves normal or enhanced activity in spared left-hemisphere regions associated with naming (Broca's area and the left posterior inferior temporal cortex) and with the meanings of words (the left posterior temporo-parietal cortex and the left anterior temporal cortex). In the right-hemisphere homologues of these regions, there was inconsistent activation within the normal group and between the deep dyslexic patients. One (CJ) showed enhanced activity (relative to the normals) in the right anterior inferior temporal cortex, the other (JG) in the right Broca's area, and both in the right frontal operculum. Although these differential right-hemisphere activations may have influenced the reading behavior of the patients, their activation patterns primarily reflect semantic and phonological systems in spared regions of the left hemisphere. These results preclude an explanation of deep dyslexia in terms of purely right-hemisphere word processing.
深度失读症是一种由左半球脑损伤导致的显著阅读障碍，其特征是在大声朗读单个单词时出现语义错误（例如，将“spirit”读成“whisky”）。针对这种综合征提出了两种解释。一种是深度失读症源于残留的左半球阅读系统，该系统在不参考语义的情况下失去了读出印刷单词的能力。另一种是深度失读症反映了右半球的单词处理过程。尽管之前在这两种假设之间进行裁决的尝试尚无定论，但现在可以通过绘制功能解剖图来解决这一争议。在本研究中，我们证明两名深度失读症患者（CJ和JG）的阅读涉及与命名相关的左半球 spared 区域（布洛卡区和左后颞下皮质）以及与单词意义相关的区域（左后颞顶叶皮质和左前颞叶皮质）的正常或增强活动。在这些区域的右半球对应区域，正常组内以及深度失读症患者之间的激活情况不一致。其中一名患者（CJ）在右前颞下皮质表现出增强的活动（相对于正常人），另一名患者（JG）在右布洛卡区表现出增强的活动，两人在右额盖部均有增强活动。尽管这些右半球的差异激活可能影响了患者的阅读行为，但其激活模式主要反映了左半球 spared 区域中的语义和语音系统。这些结果排除了用纯粹的右半球单词处理来解释深度失读症的可能性。
