Program in Physical Therapy, Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, New York, USA.
Mov Disord. 2011 Apr;26(5):862-9. doi: 10.1002/mds.23606. Epub 2011 Mar 10.
Precision grip control is important for accurate object manipulation and requires coordination between horizontal (grip) and vertical (load) fingertip forces. Manifest Huntington's disease (HD) subjects demonstrate excessive and highly variable grip force and delayed coordination between grip and load forces. Because the onset of these impairments is unknown, we examined precision grip control in premanifest HD (pre-HD) subjects. Fifteen pre-HD and 15 age- and sex-matched controls performed the precision grip task in a seated position. Subjects grasped and lifted an object instrumented with a force transducer that measured horizontal grip and vertical load forces. Outcomes were preload time, loading time, maximum grip force, mean static grip force, and variability for all measures. We compared outcomes across groups and correlated grip measures with the Unified Huntington's Disease Rating Scale and predicted age of onset. Variability of maximum grip force (P < .0001) and variability of static grip force (P < .00001) were higher for pre-HD subjects. Preload time (P < .007) and variability of preload time (P < .006) were higher in pre-HD subjects. No differences were seen in loading time across groups. Variability of static grip force (r(2) = 0.23) and variability of preload time (r(2) = 0.59) increased with predicted onset and were correlated with tests of cognitive function. Our results indicate that pre-HD patients have poor regulation of the transition between reach and grasp and higher variability in force application and temporal coordination during the precision grip task. Force and temporal variability may be good markers of disease severity because they were correlated with predicted onset of disease.
精准握力控制对于准确操纵物体非常重要，需要协调水平（握力）和垂直（负载）指尖力。亨廷顿舞蹈症（HD）患者表现出过度和高度可变的握力，并延迟了握力和负载力之间的协调。由于这些损伤的发病时间未知，我们检查了前亨廷顿舞蹈症（pre-HD）患者的精准握力控制。15 名 pre-HD 和 15 名年龄和性别匹配的对照者在坐姿下进行了精准握力任务。受试者用装有力传感器的器械握住并提起一个物体，该传感器测量水平握力和垂直负载力。结果是预加载时间、加载时间、最大握力、平均静态握力以及所有测量的变异性。我们比较了组间的结果，并将握力测量结果与统一亨廷顿病评定量表和预测发病年龄相关联。pre-HD 患者的最大握力变异性（P <.0001）和静态握力变异性（P <.00001）更高。预加载时间（P <.007）和预加载时间变异性（P <.006）在 pre-HD 患者中更高。各组之间的加载时间没有差异。静态握力变异性（r（2）= 0.23）和预加载时间变异性（r（2）= 0.59）随预测发病而增加，与认知功能测试相关。我们的结果表明，pre-HD 患者在从伸手到抓握的过渡过程中调节能力较差，在进行精准握力任务时，力的应用和时间协调的变异性更高。力和时间变异性可能是疾病严重程度的良好标志物，因为它们与疾病的预测发病相关。
