Posttraumatic Stress Symptoms Increase the Efficiency of Memory Functioning for Trauma-Related Information.

OBJECTIVE: The present study explored the resources reallocation explanation for memory biases in posttraumatic stress disorder (PTSD), whereby a preferential allocation of cognitive resources to the processing of threatening stimuli could result in both improvements in their memorization and deficits for other types of information. METHOD: To this end, 25 participants presenting significant symptoms of PTSD (i.e., total PCL-5 score ≥33) and 32 participants presenting low levels of symptoms (i.e., total PCL-5 score <20) took part in a Remember/Know recognition procedure associated with a dual-task encoding of positive, neutral, negative, and trauma-related words. In order to manipulate the availability of cognitive resources, the encoding of each word was associated with a simultaneous encoding of series of letters and numbers. RESULTS: Results replicated the increased production of Remember recognitions for trauma-related words in participants with significant PTSD symptoms. However, the dual-task load only impaired remember recognitions for non-trauma-related words. CONCLUSIONS: Contrary to expectations, these findings suggest that the encoding of trauma-related information in PTSD is relatively independent from the availability of cognitive resources. Thus, rather than reflecting an increased allocation of cognitive resources to the processing of threatening information, memory biases in PTSD appeared to be supported by an enhanced efficiency of their processing.

Combining Trauma Script Exposure With rTMS to Reduce Symptoms of Post-Traumatic Stress Disorder: Randomized Controlled Trial.

BACKGROUND: Innovative therapeutic interventions for post-traumatic stress disorder (PTSD) are required. We opted to facilitate fear extinction by combining trauma script exposure with repetitive transcranial magnetic stimulation (rTMS) to reduce symptoms of PTSD. OBJECTIVE: The efficacy and safety of 10 Hz rTMS of the right dorsolateral prefrontal cortex simultaneously with exposure to personal traumatic narrative were studied in patients with PTSD. MATERIALS AND METHODS: This trial was a single-center randomized controlled trial (NCT02584894). Patients were randomly assigned 1:1 to receive eight daily sessions of 110% of motor threshold high frequency (HF) 10 Hz rTMS (110% HF rTMS) or 70% low frequency (LF) 1 Hz rTMS (70% LF rTMS) with trauma script exposure in both groups. Severity of PTSD, depression, and anxiety were assessed before and after study treatment (one month, three months) by an assessor masked to the trial group assignment. The primary outcome was the severity of PTSD assessed by the Clinician Administered PTSD Scale (CAPS). We used mixed linear regression models for statistical comparisons. RESULTS: Thirty-eight patients (65.8% females) were randomly assigned to 110% HF rTMS (n = 18, 31.3 ± 10.0 years, 13 females) or 70% LF rTMS (n = 20, 33.5 ± 11.1 years, 12 females). From baseline to three months, mean CAPS scores decreased by 51% in the 110% HF rTMS group (from 83.7 ± 14.4 to 41.8 ± 31.9) and by 36.9% in the 70% LF rTMS group (from 81.8 ± 15.6 to 51.6 ± 23.7), but with no significant difference in improvement (time by treatment interaction -3.61 [95% confidence interval (CI), -9.70 to 2.47]; p = 0.24; effect size 0.53). One serious adverse event occurred during the study (psychogenic nonepileptic seizure). CONCLUSION: We found no evidence of difference in clinical improvement or remission rates between the 110% HF and 70% LF stimulation. These findings may reflect the importance of exposure procedure and that larger number of participants is needed.

Beyond Clinical Outcomes: Posttraumatic Stress Symptoms Favor Attentional and Memory Control Abilities for Trauma-Related Words.

Memory alterations and biases are core features of posttraumatic stress symptoms (PTSS). Although a large number of studies have investigated memory biases associated with PTSS, some inconsistencies remain regarding the nature of the mechanisms behind the threat-related biases observed in prior findings. The present study explored the extent to which inhibitory deficits, both for automatic and controlled processes, can account for these biases. Participants (N = 64) took part in a remember/know recognition procedure for positive, neutral, negative, and trauma-related words associated with negative priming and directed forgetting encoding. Half of the participants had high levels of PTSS (i.e., PCL-5 score > 40) and half had low levels (i.e., total PCL-5 score < 20). As both negative priming and directed forgetting effects are posited to depend on inhibitory abilities, we expected these effects to be absent for trauma-related words in participants with more severe PTSS. Replicating classic memory biases, participants with high levels of PTSS produced more "remember" recognition responses for trauma-related words, ηp 2 = .10. However, contrary to our expectations, directed forgetting, ηp 2 = .26; and negative priming effects were observed for trauma-related words but not for words of other valences, ηp 2 = .07 and .06, respectively. Hence, rather than the expected inhibitory deficits, our results suggest that PTSS preserve the ability to inhibit trauma-related information in both attentional and memory processes. As it appears to occur at the expense of other information, this preserved cognitive functioning for trauma-related stimuli is discussed with regard to resource reallocation theories.

Inhibitory control of threat remembering in PTSD.

Intrusive traumatic recollections suggest an inability in Posttraumatic Stress Disorder (PTSD) to control and notably to inhibit memories for trauma-related information. Supported by inhibitory deficits found on experimental settings in PTSD, memory functioning and memory biases in the disorder were usually explained through inhibitory and control deficits in the processing of trauma-related information. The present study aimed to directly assess this hypothesis by investigating memory control abilities for emotional information in PTSD. For this purpose, 34 patients diagnosed with PTSD were compared to 37 non-PTSD controls on an item-cued directed forgetting paradigm for emotional words combined with a Remember/Know recognition procedure. Results revealed enhanced amounts of Remember recognitions for trauma-related words in PTSD. Moreover, we replicated findings of memory control impairments in the disorder. However, such impairments only occurred for non-trauma-related words. Accordingly, it appeared that PTSD patients presented preserved memory control abilities for trauma-related words, at the expenses of other emotional valences. Surprisingly, PTSD patients presented a preserved ability to control and notably to inhibit their memory functioning for trauma-related material. In addition to potential theoretical and clinical relevance, these results are discussed in the light of resource reallocation hypotheses and vigilant-avoidant theories of information processing in PTSD.

Prospective and retrospective episodic metamemory in posttraumatic stress disorder.

OBJECTIVES: Posttraumatic stress disorder (PTSD) has been consistently associated with episodic memory deficits. To some extent, these deficits could be related to an impairment of metamemory in individuals with PTSD. This research consequently aims at investigating prospective (feeling-of-knowing, FOK) and retrospective (confidence) metamemory judgments for episodic information in PTSD. METHOD: Twenty participants with PTSD and without depression were compared to 30 healthy comparison participants on metamemory judgments during an episodic memory task. The concordance between metamemory judgments and recognition performance was then assessed by gamma correlations. RESULTS: The results confirmed that PTSD is associated with episodic memory impairment. Regarding metamemory, gamma correlations indicated that participants with PTSD failed to accurately predict their future memory performance as compared to the comparison group (mean FOK gamma correlations: .23 vs. .42, respectively). Furthermore, participants with PTSD made less accurate confidence judgments than comparison participants (mean confidence gamma correlations: .62 vs. .74, respectively). CONCLUSION: Our results demonstrate an alteration of both prospective and retrospective metamemory processes in PTSD, which could be of particular relevance to future therapeutic interventions focusing on metacognitive strategies.