Department of Psychology, University of Cyprus, Nicosia, Cyprus.
Center for Applied Neuroscience, University of Cyprus, Nicosia, Cyprus.
Psychophysiology. 2017 Sep;54(9):1323-1334. doi: 10.1111/psyp.12887. Epub 2017 May 8.
Alexithymia is associated with deficiencies in recognizing and expressing emotions and impaired emotion regulation, though few studies have verified the latter assertion using objective measures. This study examined startle reflex modulation by fearful imagery and its associations with heart rate variability in alexithymia. Fifty-four adults (27 alexithymic) imagined previously normed fear scripts. Startle responses were assessed during baseline, first exposure, and reexposure. During first exposure, participants, in separate trials, engaged in either shallow or deep emotion processing, giving emphasis on descriptive or affective aspects of imagery, respectively. Resting heart rate variability was assessed during 2 min of rest prior to the experiment, with high alexithymic participants demonstrating significantly higher LF/HF (low frequency/high frequency) ratio than controls. Deep processing was associated with nonsignificantly larger and faster startle responses at first exposure for alexithymic participants. Lower LF/HF ratio, reflecting higher parasympathetic cardiac activity, predicted greater startle amplitude habituation for alexithymia but lower habituation for controls. Results suggest that, when exposed to prolonged threat, alexithymics may adjust poorly, showing a smaller initial defensive response but slower habituation. This pattern seems related to their low emotion regulation ability as indexed by heart rate variability.
述情障碍与识别和表达情绪的能力缺陷以及情绪调节受损有关，但很少有研究使用客观测量来验证后一种说法。本研究通过恐惧意象来检验惊吓反射的调节及其与述情障碍中心率变异性的关系。54 名成年人（27 名述情障碍）想象了之前规范的恐惧脚本。在基线、第一次暴露和重新暴露期间评估惊吓反应。在第一次暴露期间，参与者在单独的试验中分别进行浅层或深层情绪处理，分别强调意象的描述或情感方面。在实验前 2 分钟的休息期间评估静息心率变异性，高述情障碍组的 LF/HF（低频/高频）比值显著高于对照组。对于述情障碍组，深层处理与第一次暴露时的惊吓反应幅度更大、更快有关，但对于对照组则没有显著关系。较低的 LF/HF 比值反映了更高的副交感神经心脏活动，这预示着述情障碍的惊吓幅度适应更快，但对照组的适应更慢。结果表明，当暴露于长时间的威胁时，述情障碍者可能调节不良，表现出较小的初始防御反应，但适应较慢。这种模式似乎与他们的心率变异性所反映的低情绪调节能力有关。
