Understanding the neurobiological and cognitive processes underlying the development of posttraumatic stress disorder (PTSD) and its specific symptoms may facilitate preventive intervention development. Severe traumatic stress and resulting biological stress system activations can alter contextual memory processes. This may provide a neurobiological explanation for the occurrence of intrusive memories following trauma. Investigating the associations between temporal aspects and individual variation in peri- and post-traumatic hypothalamic pituitary adrenal (HPA) axis and sympathetic nervous system (SNS) stress reactivity and memory processing may increase our understanding of intrusive symptom development. The experimental trauma film paradigm is commonly used for this purpose but lacks robust SNS and HPA axis activation. Here, we performed an RCT to investigate the effect of an adjusted trauma film paradigm containing an added brief psychosocial stressor on HPA and SNS stress reactivity throughout the experiment and intrusive memory frequency in the following week in healthy males (N = 63, mean age = 22.3). Secondary, we investigated effects on film-related declarative memory accuracy and intrusion-related characteristics, and associations between acute HPA and SNS stress reactivity, film-related memory, glucocorticoid receptor functioning and intrusion frequency and characteristics. Participants were randomized to the socially-evaluated cold pressor test (seCPT n = 29) or control condition (warm water n = 34) immediately prior to a trauma film. Linear Mixed Models revealed increased acute SNS and cortisol reactivity, lower recognition memory accuracy and more intrusions that were more vivid and distressing during the following week in the seCPT compared to control condition. Linear regression models revealed initial associations between cortisol and alpha amylase reactivity during the experimental assessment and subsequent intrusions, but these effects did not survive multiple comparison corrections. Thus, with this adjustment, we increased the translational value of the trauma film paradigm as it appears to elicit a stronger stress response that is likely more comparable to real-life trauma. The adapted paradigm may be useful to investigate individual variation in biological and cognitive processes underlying early post-trauma PTSD symptoms and could advance potential preventive interventions.

While trauma-focused psychotherapies have been shown effective in youth with PTSD, the relationship between treatment response and alterations in the autonomic nervous system (ANS) associated with PTSD, remains incompletely understood. During neutral and personalized trauma script imagery heart rate (HR), pre-ejection period (PEP) and respiratory sinus arrhythmia (RSA) were recorded in youth aged 8–18 with PTSD or partial PTSD (n = 76) and trauma-exposed controls (TEC) (n = 27) to determine ANS activity and stress reactivity. Within the patient group, 77.6% met the full DSM-IV diagnostic criteria for PTSD, the remaining 22.4% met the criteria for partial PTSD. Youth with (partial) PTSD were subsequently treated with eight sessions of either trauma-focused cognitive behavioral therapy or eye movement desensitization and reprocessing. PTSD severity was assessed using the Clinician-Administered PTSD scale for Children and Adolescents to divide patients into responders and non-responders. Youth with (partial) PTSD relative to TEC had higher overall HR during both neutral and trauma imagery (p = .05). Youth with (partial) PTSD showed RSA decrease during trauma imagery relative to neutral imagery, the reverse of TEC (p = .01). Relative to non-responders, responders demonstrated a significant baseline to posttreatment increase of RSA response to stress only when employing a ≥ 50% response criterion (p = .05) and not with the primary ≥ 30% criterion (p = .12). Our results suggest overall higher HR and sympathetic nervous system activity as well as vagal withdrawal in response to stress in youth with (partial) PTSD and only provide partial support for normalization of the latter with successful trauma-focused psychotherapy.

BackgroundBilateral sensory stimulation (BLS), such as eye movements or alternating tactile stimulation, is a key component of Eye Movement Desensitisation and Reprocessing (EMDR), a recommended treatment for post-traumatic stress disorder (PTSD). However, the neurophysiological mechanisms underlying BLS remain poorly understood.AimsThis study examined the physiological effects of visual and tactile BLS on frontal electroencephalography (EEG) activity and autonomic arousal in patients with PTSD and healthy controls, by varying the type of stimulation in different emotional stimuli.MethodTwenty female PTSD patients and twenty matched healthy controls participated in a counterbalanced, within-subjects design. Participants recalled a subjectively stressful or neutral event while receiving visual or tactile BLS. Frontal EEG and peripheral psychophysiological measures were recorded before and after stimulation. Data were analysed using mixed model analysis to examine the effects of stimulation type, memory condition and group.ResultsBoth visual and tactile BLS significantly increased the total power of frontal EEG and decreased spectral edge frequency and peripheral physiological activation. These effects were consistent between the groups and memory conditions.ConclusionsBLS, regardless of visual or tactile modality or emotional memory content, is associated with increased frontal EEG activity and reduced autonomic arousal. These findings support the hypothesis that BLS facilitates top-down cortical regulation, potentially aiding emotional processing in EMDR by using an inherent mechanism to promote psychological recovery. More research is needed to clarify the neural mechanisms and clinical implications.