Background: There were 1.2 million registered heroin users in China by the end of 2011, but little research in the country has focused on the neuropsychological functioning of these individuals.
Aim: Assess error-related negativity (ERN) - an important indicator of high-level cognitive functioning - among males with heroin dependence undergoing rehabilitation.
Method: Twenty male patients in a rehabilitation center who met DSM-IV criteria for heroin dependence and 15 healthy male controls completed 800 trials of Erikson flanker tasks to provoke ERN waves on the 32-electrode electroencephalograph (EEG) when erroneous responses are induced by presenting incongruent flankers around the target stimulus. Mean error rates and reaction times for the task, and the amplitude and latency of crude ERN waves and standardized ERN waves (created by subtracting the wave for correct responses from that for incorrect responses) at three frontal midline EEG electrodes (Fz, FCz, and Cz) were compared between patients and controls.
Results: There was no significant difference in error rates between patients and controls but the reaction times for both erroneous and correct responses were shorter in patients than controls. The amplitude of both crude and standardized ERN waves was lower in patients than controls, but this difference became non-significant after adjustment for the lower educational level in the patient group. The latency of the peak value in both the crude and standardized ERN waves was significantly shorter in the patient group; this difference remained significant after adjustment for educational level. There was a significant correlation between the negative amplitude of the standardized ERN wave and the duration of heroin use.
Conclusion: These findings suggest impaired impulse control and abnormal error-monitoring functions in persons with a history of heroin dependence and add to the growing literature on the neurological mechanisms related to cognitive dysfunction in individuals with addictive disorders.
背景: 截止2011年底，全国登记吸毒人群中滥用海洛因人员共115.6万人，然而国内对海洛因依赖者神经心理功能的研究较少。
目的: 探讨康复期男性海洛因依赖者高级认知功能的重要指标之一，即错误相关负电位（error-related negativity，ERN）的特征。
方法: 符合DSM-IV诊断标准的男性海洛因依赖者20例和健康对照者15人完成视觉Eriksen Flanker刺激任务。该任务共800个刺激，在目标刺激两侧呈现与目标不完全一致的干扰刺激，以此诱发错误应答及ERN。记录被试头皮32导脑电图（EEG）信号。比较患者组与对照组的平均错误率和执行任务的反应时，并比较额叶中线3处EEG电极位置（Fz、FCz和Cz）原始ERN以及ERN差异波（在错误应答波基础上减去正确应答波后的负波）的波幅和潜伏期。
结果: 两组的错误率无明显差异，但与对照组相比，患者组的正确反应时和错误反应时均缩短。无论是原始ERN还是ERN差异波，患者组的波幅均低于对照组。由于患者组受教育年限较低，经校正后，两组波幅差异无统计学意义。患者组的原始ERN和ERN差异波的潜伏期均比对照组短，校正受教育水平后差异仍有统计学意义。海洛因依赖组ERN差异波波幅与吸毒年限呈正相关。
结论: 研究结果提示有海洛因依赖史的个体存在冲动控制能力受损以及错误监控功能异常。关于成瘾障碍个体认知功能障碍的神经机制的研究日益增加，本研究也为这一文献库添砖加瓦。