UCL Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK.
Neuropsychologia. 2011 Jan;49(2):264-70. doi: 10.1016/j.neuropsychologia.2010.11.016. Epub 2010 Nov 20.
Visuomotor integration deficits have been documented in Huntington disease (HD), with disproportionately more impairment when direct visual feedback is unavailable. Visuomotor integration under direct and indirect visual feedback conditions has not been investigated in the stage before clinical onset ('premanifest'). However, given evidence of posterior cortical atrophy in premanifest HD, we predicted visuomotor integration would be adversely affected, with greater impairment under conditions of indirect visual feedback.
239 subjects with the HD CAG expansion, ranging from more than a decade before predicted clinical onset until early stage disease, and 122 controls, completed a circle-tracing task, which included both direct and indirect visual feedback conditions. Measures included accuracy, speed, and speed of error detection and correction. Using brain images acquired with 3T magnetic resonance imaging (MRI), we generated grey and white matter volumes with voxel-based morphometry, and analyzed correlations with circle-tracing performance.
Compared with controls, early HD was associated with lower accuracy and slower performance in both circle-tracing conditions. Premanifest HD was associated with lower accuracy in both conditions and fewer rotations in the direct condition. Comparing performance in the indirect condition with the direct condition, HD gene expansion-carriers exhibited a disproportionate increase in errors relative to controls. Premanifest and early HD groups required longer to detect and correct errors, especially in the indirect condition. Slower performance in the indirect condition was associated with lower grey matter volumes in the left somatosensory cortex in VBM analyses.
Visuomotor integration deficits are evident many years before the clinical onset of HD, with deficits in speed, accuracy, and speed of error detection and correction. The visuomotor transformation demands of the indirect condition result in a disproportionate decrease in accuracy in the HD groups. Slower performance under indirect visual feedback was associated with atrophy of the left-hemisphere somatosensory cortex, which may reflect the proprioceptive demands of the task.
亨廷顿病（HD）存在视觉运动整合缺陷，当直接视觉反馈不可用时，这种缺陷更为明显。在临床发病前（“前显型”）阶段，尚未对直接和间接视觉反馈条件下的视觉运动整合进行研究。然而，鉴于前显型 HD 中存在皮质后区萎缩的证据，我们预测视觉运动整合将受到不利影响，间接视觉反馈条件下的损伤更大。
239 名携带 HD CAG 扩展的受试者，从预测临床发病前 10 多年到疾病早期阶段，以及 122 名对照者，完成了圆形跟踪任务，其中包括直接和间接视觉反馈条件。测量包括准确性、速度以及错误检测和纠正的速度。使用 3T 磁共振成像（MRI）采集的大脑图像，我们使用基于体素的形态测量学生成了灰质和白质体积，并分析了与圆形跟踪表现的相关性。
与对照组相比，早期 HD 与两种圆线追踪条件下的准确性降低和速度较慢有关。前显型 HD 与两种条件下的准确性降低以及直接条件下的旋转次数减少有关。与直接条件相比，在间接条件下，HD 基因扩展携带者的错误相对对照组不成比例增加。前显型和早期 HD 组在间接条件下需要更长的时间来检测和纠正错误，尤其是在间接条件下。间接条件下的运动速度较慢与 VBM 分析中左侧体感皮层灰质体积较低有关。
在 HD 临床发病前多年，就存在视觉运动整合缺陷，表现为速度、准确性以及错误检测和纠正的速度较慢。间接条件下的视觉运动转换要求导致 HD 组的准确性不成比例下降。间接视觉反馈下的运动速度较慢与左侧半球体感皮层萎缩有关，这可能反映了任务的本体感受需求。
