Johnson Patricia L, Potts Geoffrey F, Sanchez-Ramos Juan, Cimino Cynthia R
a Department of Psychology , University of South Florida , Tampa , FL , USA.
b Department of Neurology , University of South Florida , Tampa , FL , USA.
J Clin Exp Neuropsychol. 2017 Sep;39(7):694-706. doi: 10.1080/13803395.2016.1257702. Epub 2016 Nov 28.
Few studies have directly investigated impulsivity in Huntington's disease (HD) despite known changes in dopaminergic and frontal functioning, changes that have been associated with impulsivity in other disorders and in the normal population. This study sought to further categorize impulsivity in HD through examining differences in self-reported impulsivity between community controls and HD patients, the relationship between executive dysfunction and impulsivity, and the relationship of a reward/punishment behavioral inhibition task in relation to these self-report measures. It was expected that HD patients would report higher impulsivity and executive dysfunction and that these measures would relate to a reward/punishment behavioral inhibition task.
The Barratt Impulsivity Scale (BIS-11) and Behavioral Inhibition/Behavioral Activation Scale (BIS/BAS) were completed, and the Mini-Mental State Examination (MMSE) and a reward-based flanker task with punishing and rewarding conditions were administered to 22 HD patients and 14 control participants.
HD patients reported higher trait impulsivity (BIS-11) and executive dysfunction (Frontal Systems Behavior Scale, FrSBE) but not increased impulsivity on the BIS/BAS relative to controls. Higher BIS-11 scores were related to increased self-reported executive dysfunction and the attention/working memory factor of the MMSE. On a reward/punishment behavioral inhibition task, BAS was uniquely related to increased accuracy on rewarding trials of the flanker task, but was not related to punishing trials in HD patients.
The relationships found suggest that trait impulsivity is reported higher in HD and may not be driven by altered reward evaluation and the appetitive nature of stimuli but rather by increased executive dysfunction and lack of sensitivity to punishment. Impulsivity in HD may represent a combination of trait impulsivity, altered dopaminergic circuitry, and executive dysfunction. Understanding impulsivity in HD is important as it is related to increased risk to the patient and difficult behaviors for the caregiver, and sheds light on the disease process.
尽管已知亨廷顿舞蹈症（HD）患者存在多巴胺能和额叶功能变化，且这些变化在其他疾病及正常人群中与冲动性有关，但很少有研究直接调查HD患者的冲动性。本研究旨在通过检查社区对照组与HD患者自我报告的冲动性差异、执行功能障碍与冲动性之间的关系以及奖励/惩罚行为抑制任务与这些自我报告测量之间的关系，进一步对HD患者的冲动性进行分类。预计HD患者会报告更高的冲动性和执行功能障碍，且这些测量结果将与奖励/惩罚行为抑制任务相关。
对22名HD患者和14名对照参与者进行了巴拉特冲动性量表（BIS-11）和行为抑制/行为激活量表（BIS/BAS）测试，并实施了简易精神状态检查表（MMSE）以及一项具有惩罚和奖励条件的基于奖励的侧翼任务。
与对照组相比，HD患者报告了更高的特质冲动性（BIS-11）和执行功能障碍（额叶系统行为量表，FrSBE），但在BIS/BAS上的冲动性并未增加。较高的BIS-11得分与自我报告的执行功能障碍增加以及MMSE的注意力/工作记忆因子相关。在奖励/惩罚行为抑制任务中，BAS与侧翼任务奖励试验中准确性的提高独特相关，但与HD患者的惩罚试验无关。
所发现的关系表明，HD患者报告的特质冲动性更高，可能不是由奖励评估改变和刺激的欲求性质驱动，而是由执行功能障碍增加和对惩罚缺乏敏感性驱动。HD患者的冲动性可能代表特质冲动性、多巴胺能回路改变和执行功能障碍的综合表现。了解HD患者的冲动性很重要，因为它与患者风险增加及照顾者面临的困难行为有关，并有助于揭示疾病过程。
