Background: Neurophysiological models link dissociation (e.g. feeling detached during or after a traumatic event) to hypoarousal. It is currently assumed that the initial passive reaction to a threat may coincide with a blunted autonomic response, which constitutes the dissociative subtype of post-traumatic stress disorder (PTSD). Objective: Within this systematic review we summarize research which evaluates autonomic nervous system activation (e.g. heart rate, blood pressure) and dissociation in PTSD patients to discern the validity of current neurophysiological models of trauma-related hypoarousal. Method: Of 553 screened articles, 28 studies (N = 1300 subjects) investigating the physiological response to stress provocation or trauma-related interventions were included in the final analysis.Results: No clear trend exists across all measured physiological markers in trauma-related dissociation. Extracted results are inconsistent, in part due to high heterogeneity in experimental methodology. Conclusion:The current review is unable to provide robust evidence that peri-and posttraumatic dissociation are associated with hypoarousal, questioning the validity of distinct psychophysiological profiles in PTSD.La disociación relacionada con el trauma y el sistema nervioso autónomo: Una revisión bibliográfica sistemática de los correlatos psicofisiológicos de la experiencia disociativa en pacientes con TEPT Antecedentes: Los modelos neurofisiológicos vinculan la disociación (por ejemplo, la sensación de desapego durante o después de un evento traumático) con la hipoactivación. Actualmente se asume que la reacción pasiva inicial ante una amenaza puede coincidir con una respuesta autonómica embotada, lo que constituye el subtipo disociativo del trastorno de estrés postraumático (TEPT). Objetivo: En esta revisión sistemática resumimos las investigaciones que evalúan la activación del sistema nervioso autónomo (por ejemplo, la frecuencia cardíaca, la presión arterial) y la disociación en pacientes con TEPT para discernir la validez de los modelos neurofisiológicos actuales de la hipoactivación relacionada con el trauma. Método: De 553 artículos seleccionados, se incluyeron en el análisis final 28 estudios (N=1300 sujetos) que investigaban la respuesta fisiológica a la provocación del estrés o a las intervenciones relacionadas con el trauma. Resultados: No existe una tendencia clara en todos los marcadores fisiológicos medidos en la disociación relacionada con el trauma. Los resultados extraídos son inconsistentes, en parte debido a la alta heterogeneidad en la metodología experimental. Conclusión: La presente revisión no puede aportar pruebas sólidas de que la disociación peri y postraumática esté asociada a la hipoactivación, lo que cuestiona la validez de los distintos perfiles psicofisiológicos en el TEPT 创伤相关解离和自主神经系统：一项对 PTSD 患者解离体验的心理生理相 关因素的系统文献综述 背景：神经生理学模型将解离(例如，在创伤事件期间或之后感到超然)与低唤起联系起 来。目前假设对威胁的初始被动反应可能与迟钝的自主反应同时发生，这构成了创伤后应 激障碍 (PTSD) 的解离亚型。 ARTICLE HISTORY

Assessing symptom frequencies is a core feature of psychological diagnostics and any evaluation of the effectiveness of a therapeutic approach is based on these. However, heuristic strategies are employed when estimating the frequency of past events, which can lead to recall biases. While the few studies published to date indicate that patients suffering from posttraumatic stress disorder tend to underreport dissociative symptoms, there is also some evidence for the tendency to overreport dissociative symptoms. To gain insights into absolute frequencies of dissociative symptoms and retrospective reporting styles we used ambulatory assessment in 42 participants with PTSD symptoms. Participants logged their symptoms via smartphone over 2 weeks and then estimated them again retrospectively for this entire period. In comparison to the daily logs, more participants tended to retrospectively underestimate experienced symptoms in their frequency for almost all items. The results reported in this sample thus argue for an underreporting style instead of overreporting of dissociative symptoms.

People suffering from chronic dissociation often experience stress and detachment during self-perception. We tested 18 people with dissociative disorders not otherwise specified (DDNOS; compared with a matched sample of 18 healthy controls) undergoing a stress-inducing facial mirror confrontation paradigm, and measured acute dissociation and frontal electroencephalography (measured with a four-channel system) per experimental condition (e.g. confrontation with negative cognition). Linear mixed models indicated a significant group×time×condition effect, with DDNOS group depicting less electroencephalography power than healthy controls at the beginning of mirror confrontation combined with negative and positive cognition. This discrepancy – most prominent in the negative condition – diminished in the second minute. Correlational analyses depicted a positive association between initial electroencephalography power and acute dissociation in the DDNOS group. These preliminary findings may indicate altered neural processing in DDNOS, but require further investigation with more precise electroencephalography measures.

Introduction The Sniffin’ Sticks threshold test is widely used to assess olfactory threshold due to its high reliability and validity. Nevertheless, this test procedure is quite long with an average duration of 10 to 20 min. In study designs that require multiple olfactory threshold tests on short intervals, this could exhaust participants. To counteract this limitation, we developed the informed-four-reversal (INFOUR) short version of the Sniffin’ Sticks threshold test for repeated measurement designs and piloted it in a sample of normosmic participants. Methods Forty-two participants performed the original Sniffin’ Sticks version before being assigned either to the control group that repeated the original version or to the test group that conducted the INFOUR short version. Results The correlation between the original version at T1 and INFOUR at T2 was r = .75 and did not differ significantly from the retest reliability of the original version. Compared to the original version, the INFOUR took 42% less time to perform. Conclusion The INFOUR leads to a significant time saving, while maintaining good validity. Implications Therefore, this approach has the potential to be a useful tool for study protocols with repeated olfactory threshold measurements. In particular, when research protocols are time intensive or testing needs to the shortened, because the interventional effects are short or subtle.