Investigating the effect of proactive interference control training on intrusive memories

ABSTRACT

Intrusive re-experiencing is a hallmark symptom of Posttraumatic Stress Disorder (PTSD). According to prominent models of intrusive phenomena, intrusive memories may result from impairments in the efficiency of working memory capacity (WMC), more specifically proactive interference control. Yet, experimental research is scarce. Therefore, the present study aimed to investigate experimentally the role of proactive interference control in intrusive memories. We randomly assigned 57 healthy participants to either receive a high interference control training or a low interference control training. Participants were then exposed to highly distressing film clips. WMC was assessed before and after the training. Intrusion symptoms were assessed directly post-training and after one week using an Intrusion Provocation Task (IPT), a one-week intrusions diary, and the retrospective intrusion subscale of the Impact of Event Sale – Revised (IES-R). Results indicated that both groups reported improvements in WMC and fewer intrusions on the second IPT post-training, with no differences between groups. Similarly, no group differences on intrusions were found at one-week follow-up (i.e., intrusion diary and IES-R). To conclude, these data are not consistent with the hypothesis that WMC plays a role in intrusive re-experiencing. Implications for future research are discussed.

HIGHLIGHTS

• Intrusions in PTSD may result from impairments in proactive interference control (PIC).• This study manipulated PIC.• There was no difference in outcomes of high versus low PIC training.• Results do not support a causal role of PIC.

La re-experiencia intrusiva es un síntoma distintivo del trastorno por estrés postraumático (TEPT). De acuerdo con los prominentes modelos de fenómenos intrusivos, las memorias intrusivas pueden resultar en deterioros en la eficiencia de la capacidad de memoria de trabajo (CMT), más específicamente del control proactivo de interferencias. Sin embargo, la investigación experimental a este respecto es escasa. Por lo tanto, el presente estudio tuvo como objetivo investigar experimentalmente el papel del control proactivo de interferencias en las memorias intrusivas. Asignamos aleatoriamente 57 participantes sanos a recibir, ya sea, un entrenamiento de control de alta interferencia o un entrenamiento de control de baja interferencia. Luego, los participantes fueron expuestos a videoclips de películas altamente angustiantes. La CMT fue evaluada antes y después del entrenamiento. Los síntomas de intrusión se evaluaron directamente después del entrenamiento y después de una semana utilizando una Tarea de Provocación de Intrusión (IPT), registro diario de intrusiones (por una semana), y la subescala de intrusión retrospectiva de la Escala del Impacto del Evento - Revisada (IES-R). Los resultados indicaron que ambos grupos experimentaron mejoras en la CMT y reducción de intrusiones en la segunda IPT posterior al entrenamiento, sin diferencias entre los grupos. De manera similar, no se encontraron diferencias de grupo en las intrusiones en el seguimiento de una semana (es decir, en el diario de intrusiones y la IES-R). Para concluir, estos datos no son consistentes con la hipótesis de que la CMT desempeña un papel en la re-experiencia intrusiva. Se discuten las implicaciones para futuras investigaciones.

闯入性再体验是创伤后应激障碍（PTSD）的标志性症状。根据闯入现象的经典模型，闯入性记忆可能是由工作记忆容量（WMC）效率的损害引起的，更具体地说是主动干扰控制。然而，这方面实验研究很少。因此，本研究通过实验研究主动干扰控制在闯入性记忆中的作用。我们随机分配了57名健康被试，以接受高干扰控制训练或低干扰控制训练。然后被试接触到令人非常痛苦的电影片段。在训练前后对WMC进行了评估。在训练后和一周后随访使用闯入激发任务（IPT），一周闯入症状日记以及事件影响量表修订版（IES－R）的回顾性闯入子量表直接评估闯入症状。结果表明，两组均报告WMC改善，第二次IPT训练后闯入较少，两组间无差异。同样，在一周的随访中没有发现闯入的群体差异（即闯入日记和IES-R）。总之，这些数据与WMC在闯入性再体验中发挥作用的假设不一致。文中讨论了对未来研究的启示。

KEYWORDS:

• Intrusions
• working memory capacity
• emotional disorders
• trauma
• inhibition control
• trauma film paradigm
• operation span task
• reading span task

PALABRAS CLAVES:

• intrusiones
• capacidad de memoria de trabajo
• trastornos emocionales
• trauma
• control inhibitorio
• paradigma experimental trauma film
• tarea de retención de operaciones
• tarea de retención de lectura

关键词:

• 闯入
• 工作记忆能力
• 情绪障碍
• 创伤
• 抑制控制
• 创伤影片范式
• 操作广度任务
• 阅读广度任务

Acknowledgments

We thank Jens Schulte for his help with programming the computer tasks. Marcella L. Woud is supported by a grant of the Deutsche Forschungsgemeinschaft (DFG; WO2018/2-1).

Disclosure statement

No potential conflict of interest was reported by the authors.

Ethical approval

All procedures performed in the present study involved human participants and were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The study was approved by the local ethic committee of the Ruhr-Universität Bochum (ethical approval number: 181).

Informed consent

Informed consent was obtained from all individual participants included in the study.

Additional information

Funding

This work was supported by the Daimler and Benz Foundation (32-12/4). The Daimler and Benz Foundation had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.