Tavakoli Paniz, Boafo Addo, Dale Allyson, Robillard Rebecca, Greenham Stephanie L, Campbell Kenneth
Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.
Department of Psychiatry, University of Ottawa, Ottawa, ON, Canada.
Front Psychiatry. 2018 Mar 19;9:85. doi: 10.3389/fpsyt.2018.00085. eCollection 2018.
Impaired executive functions, modulated by the frontal lobes, have been suggested to be associated with suicidal behavior. The present study examines one of these executive functions, attentional control, maintaining attention to the task-at-hand. A group of inpatient adolescents with acute suicidal behavior and healthy controls were studied using a passively presented auditory optimal paradigm. This "optimal" paradigm consisted of a series of frequently presented homogenous pure tone "standards" and different "deviants," constructed by changing one or more features of the standard. The optimal paradigm has been shown to be a more time-efficient replacement to the traditional oddball paradigm, which makes it suitable for use in clinical populations. The extent of processing of these "to-be-ignored" auditory stimuli was measured by recording event-related potentials (ERPs). The P3a ERP component is thought to reflect processes associated with the capturing of attention. Rare and novel stimuli may result in an executive decision to switch attention away from the current cognitive task and toward a probe of the potentially more relevant "interrupting" auditory input. On the other hand, stimuli that are quite similar to the standard should not elicit P3a. The P3a has been shown to be larger in immature brains in early compared to later adolescence. An overall enhanced P3a was observed in the suicidal group. The P3a was larger in this group for both the environmental sound and white noise deviants, although only the environmental sound P3a attained significance. Other deviants representing only a small change from the standard did not elicit a P3a in healthy controls. They did elicit a small P3a in the suicidal group. These findings suggest a lowered threshold for the triggering of the involuntary switch of attention in these patients, which may play a role in their reported distractibility. The enhanced P3a is also suggestive of an immature frontal central executive and may provide a promising marker for early identification of some of the risk factors for some of the cognitive difficulties linked to suicidality.
由额叶调节的执行功能受损被认为与自杀行为有关。本研究考察其中一种执行功能，即注意力控制，也就是对手头任务保持专注。使用被动呈现的听觉最优范式对一组有急性自杀行为的住院青少年和健康对照组进行了研究。这种“最优”范式由一系列频繁呈现的同质纯音“标准音”和不同的“偏差音”组成，通过改变标准音的一个或多个特征来构建。最优范式已被证明是传统oddball范式更节省时间的替代方法，使其适用于临床人群。通过记录事件相关电位（ERP）来测量对这些“需忽略”听觉刺激的处理程度。P3a ERP成分被认为反映了与注意力捕捉相关的过程。罕见和新颖的刺激可能导致执行决策，将注意力从当前认知任务转移到对潜在更相关的“干扰性”听觉输入的探测上。另一方面，与标准音非常相似的刺激不应引发P3a。研究表明，与青少年后期相比，早期未成熟大脑中的P3a更大。在自杀组中观察到总体上P3a增强。该组中环境声音和白噪声偏差音的P3a都更大，尽管只有环境声音的P3a达到显著水平。在健康对照组中，其他仅与标准音有微小变化的偏差音未引发P3a。它们在自杀组中确实引发了小的P3a。这些发现表明这些患者中触发非自愿注意力切换的阈值降低，这可能在他们所报告的注意力分散中起作用。增强的P3a也提示额叶中央执行功能不成熟，可能为早期识别与自杀倾向相关的一些认知困难的风险因素提供一个有前景的标志物。
