Department of Psychology, Monash University, Clayton, Victoria 3168, Australia.
Behav Neurol. 1994;7(2):67-77. doi: 10.3233/BEN-1994-7204.
Visual reaction time (RT) studies on patients with right hemisphere (RH) damage have demonstrated that the attentional imbalance to stimuli occupying left and right positions exists even within the "intact" ipsilesional hemifield. The purpose of the present study was to test whether such patients might also exhibit relative left-sided impairments in the tactile modality, where stimuli and responses involve the index and middle fingers of the non-hemiplegic ipsilesional hand. Eight patients with RH damage, and eight matched normal controls, were tested using a vibrotactile choice RT paradigm, with the responding hand held in prone or supine posture, and located either at the body midline, or in left or right hemispace. Patients showed significantly slower RTs with the left than the right finger in both hand postures, a difference which remained constant as a function of the hemispatial location of the responding hand. In the prone posture, patients' left finger RTs were slower than those of controls, who showed no difference between left and right finger RTs, while their right finger RTs were faster than those of controls. In the supine posture, both patients and controls exhibited slower left than right finger RTs, though in controls the left finger disadvantage was attributed to biomechanical rather than attentional factors. Patients also made more errors with left than right finger stimuli, both as failures of detection and as incorrect responses, while controls made fewer errors overall and showed no differences between fingers. These data demonstrate a bias in the distribution of attention to tactile stimuli at an intra-limb level, and suggest that the attentional imbalance created by RH damage may be supramodal.
对右脑（RH）损伤患者的视觉反应时间（RT）研究表明，即使在“完整”的同侧视野内，对占据左右位置的刺激也存在注意力不平衡。本研究的目的是测试此类患者是否在触觉模态中也表现出相对的左侧损伤，其中刺激和反应涉及非偏瘫同侧手的食指和中指。使用振动触觉选择 RT 范式对 8 名右脑损伤患者和 8 名匹配的正常对照者进行了测试，反应手分别处于俯卧或仰卧姿势，位于身体中线或左侧或右侧半空间。患者在两种手姿势下用左手的 RT 明显慢于右手，这种差异随着反应手的半空间位置而保持不变。在俯卧姿势下，患者的左手 RT 比对照组慢，对照组左手和右手 RT 之间没有差异，而他们的右手 RT 比对照组快。在仰卧姿势下，患者和对照组的左手 RT 都比右手 RT 慢，尽管在对照组中，左手的劣势归因于生物力学因素而不是注意力因素。患者用左手刺激的错误也比右手多，既包括检测失败，也包括错误反应，而对照组总的错误较少，且手指之间没有差异。这些数据表明，在肢体内部水平上，触觉刺激的注意力分布存在偏差，并且表明右脑损伤引起的注意力不平衡可能是超模式的。
