Department of Psychology, General and Experimental Psychology/Neuro-cognitive Psychology, Ludwig Maximilian University, Munich, Germany.
Neuropsychologia. 2010 Jan;48(1):298-308. doi: 10.1016/j.neuropsychologia.2009.09.018.
Patients with right hemisphere lesions often show contralesional neglect. Recent research focused on deficits beyond the typical neglect symptoms observed in the horizontal plane. Studies investigating deficits in the frontal and sagittal plane revealed impairments in the judgment of the subjective vertical. Systematic deviations in the subjective vertical have been demonstrated in the visual and tactile modality, indicating a supramodal spatial orientation deficit. Further, the magnitude of deviations appears to be manipulable by modulations of body posture. The present study investigated the subjective tactile vertical (STV) in neglect patients in the frontal and sagittal plane and its dependence on posture. Neglect patients and healthy controls performed tactile-spatial judgments of axis orientations in supine and upright posture. Neglect patients displayed a marked variability as well as a systematic tilt in their STV judgments. The STV was tilted counterclockwise in the frontal and backward in the sagittal plane. This tilt was larger in severe compared to moderate neglect patients, while it was not evident in healthy subjects. Our results support previous evidence and indicate a multisensory spatial orientation deficit in neglect patients which is related to neglect severity. Further, we found that performance of neglect patients deteriorated in supine compared to upright posture. This finding conflicts with the suggestion of a performance benefit in supine posture due to reduced (asymmetric) gravitational input. The negative effect of supine posture on the spatial bias in neglect is discussed with respect to a presumably further reduced intrinsic alertness state in the typically hypo-aroused neglect patients.
右侧大脑损伤的患者常表现为对侧忽略。最近的研究重点关注超出水平方向典型忽略症状的缺陷。研究表明，在额状面和矢状面都存在对主观垂直的判断缺陷。在视觉和触觉模态中都观察到了主观垂直的系统性偏差，表明存在超模态空间定向缺陷。此外，通过改变身体姿势，可以调节偏差的幅度。本研究调查了额状面和矢状面忽略患者的主观触觉垂直（STV）及其对姿势的依赖性。忽略患者和健康对照组在仰卧位和直立位时进行了触觉空间轴方向判断。忽略患者的 STV 判断表现出明显的可变性和系统性倾斜。在额状面，STV 逆时针倾斜；在矢状面，STV 向后倾斜。与中度忽略患者相比，严重忽略患者的倾斜更大，而健康受试者则没有明显的倾斜。我们的研究结果支持了之前的研究证据，表明忽略患者存在多感觉空间定向缺陷，且与忽略严重程度有关。此外，我们发现忽略患者在仰卧位时的表现比直立位时更差。这一发现与由于减少的（不对称的）重力输入导致仰卧位时表现更好的假设相矛盾。本文还讨论了仰卧位对忽略中空间偏差的负面影响，这可能与典型低警觉状态的忽略患者内在警觉性进一步降低有关。
