How eye movements in EMDR work: Changes in memory vividness and emotionality

Background and objectives

Eye movements (EM) during recall of an aversive memory is a treatment element unique to Eye Movement Desensitization and Reprocessing (EMDR). Experimental studies have shown that EM reduce memory vividness and/or emotionality shortly after the intervention. However, it is unclear whether the immediate effects of the intervention reflect actual changes in memory. The aim of this study was to test whether immediate reductions in memory vividness and emotionality persist at a 24 h follow up and whether the magnitude of these effects is related to the duration of the intervention.

Methods

Seventy-three undergraduates recalled two negative autobiographical memories, one with EM (“recall with EM”) and one without (“recall only”). Half of participants recalled each memory for four periods of 24 s, the other half for eight periods of 24 s. Memory vividness/emotionality were self-rated at a pre-test, an immediate post-test, and a 24 h follow-up test.

Results

In both duration groups, recall with EM, but not recall only, caused an immediate decrease in memory vividness. There were no immediate reductions in memory emotionality. Furthermore, only the ‘eight periods’ group showed that recall with EM, but not recall only, caused a decrease in both memory emotionality and memory vividness from the pre-test to the follow-up.

Limitations

Only self-report measures were used.

Conclusions

The findings suggest that recall with EM causes 24-h changes in memory vividness/emotionality, which may explain part of the EMDR treatment effect, and these effects are related to intervention duration.     

EMDR and mindfulness. Eye movements and attentional breathing tax working memory and reduce vividness and emotionality of aversive ideation

Background and objectives

Eye Movement Desensitization and Reprocessing (EMDR) and Mindfulness-Based Cognitive Therapy (MBCT) are effective in reducing the subjective impact of negative ideation. In both treatments, patients are encouraged to engage in a dual-task (eye movements (EM) in the case of EMDR and attentional breathing (AB) in the case of MBCT) while they experience negative thoughts or images. Working memory theory explains the effects of EM by suggesting that it taxes limited working memory resources, thus rendering the image less vivid and emotional. It was hypothesized that both AB and EM tax working memory and that both reduce vividness and emotionality of negative memories.

Methods

Working memory taxation by EM and AB was assessed in healthy volunteers by slowing down of reaction times. In a later session, participants retrieved negative memories during recall only, recall + EM and recall + AB (study 1). Under improved conditions the study was replicated (study 2).

Results

In both studies and to the same degree, attentional breathing and eye movements taxed working memory. Both interventions reduced emotionality of memory in study 1 but not in study 2 and reduced vividness in study 2 but not in study 1.

Limitations

EMDR is more than EM and MBCT is more than AB. Memory effects were assessed by self reports.

Conclusions

EMDR and MBCT may (partly) derive their beneficial effects from taxing working memory during recall of negative ideation.     

Memory biases in remitted depression: The role of negative cognitions at explicit and automatic processing levels

Background and objectives

Cognitive models propose that depression is caused by dysfunctional schemas that endure beyond the depressive episode, representing vulnerability factors for recurrence. However, research testing negative cognitions linked to dysfunctional schemas in formerly depressed individuals is still scarce. Furthermore, negative cognitions are presumed to be linked to biases in recalling negative self-referent information in formerly depressed individuals, but no studies have directly tested this association.In the present study, we evaluated differences between formerly and never-depressed individuals in several experimental indices of negative cognitions and their associations with the recall of emotional self-referent material.

Methods

Formerly (n = 30) and never depressed individuals (n = 40) completed measures of explicit (i.e., scrambled sentence test) and automatic (i.e., lexical decision task) processing to evaluate negative cognitions. Furthermore participants completed a self-referent incidental recall task to evaluate memory biases.

Results

Formerly compared to never depressed individuals showed greater negative cognitions at both explicit and automatic levels of processing. Results also showed greater recall of negative self-referent information in formerly compared to never-depressed individuals. Finally, individual differences in negative cognitions at both explicit and automatic levels of processing predicted greater recall of negative self-referent material in formerly depressed individuals.

Limitations

Analyses of the relationship between explicit and automatic processing indices and memory biases were correlational and the majority of participants in both groups were women.

Conclusions

Our findings provide evidence of negative cognitions in formerly depressed individuals at both automatic and explicit levels of processing that may confer a cognitive vulnerability to depression.     

Contextual representations increase analogue traumatic intrusions: evidence against a dual-representation account of peri-traumatic processing

Background and objectives

Information processing accounts of post-traumatic stress disorder (PTSD) state that intrusive memories emerge due to a lack of integration between perceptual and contextual trauma representations in autobiographical memory. This hypothesis was tested experimentally using an analogue trauma paradigm in which participants viewed an aversive film designed to elicit involuntary recollections.

Method

Participants viewed scenes from the film either paired with contextual information or with the contextual information omitted. After viewing the film participants were asked to record for one week any involuntary intrusions for the film using a provided intrusions diary.

Results

The results revealed a significant increase in analogue intrusions for the film when viewed with contextual information in comparison to when the film was viewed with the contextual information omitted. In contrast there was no effect of contextual information on valence ratings or voluntary memory for the film, or on the reported vividness and emotionality of the intrusions.

Limitations

The analogue trauma paradigm may have failed to reproduce the effect of extreme stress on encoding that is postulated to occur during PTSD.

Conclusions

The findings have potential implications for trauma intervention as they suggest that the contextual understanding of a scene during encoding can be integral to the subsequent occurrence of traumatic intrusions. The pattern of results found in the study are inconsistent with dual-representation accounts of intrusive memory formation, and instead provide new evidence that contextual representations play a casual role in increasing the frequency of involuntary intrusions for traumatic material.     

Aging effects on ERP correlates of emotional word discrimination

Objective

To explore age-, and valence specific ERP-characteristics of word-discrimination processes.

Methods

A group of young (mean age: 21.26 yrs) and elderly (mean age: 65.73 yrs) individuals participated. The task was to respond to a word (target) with valence (neutral, negative, positive) and disregard others (non-target) with a different valence. Behavioral indices and the N4 and late positive complex (LPC) components were analyzed.

Results

For words with negative valence performance was better for non-target stimuli in the young. Higher N4 was elicited by negative non-target words in the fronto-central areas. Target words elicited a P3b-like LPC in the young while a P3a-like LPC was observed in the elderly.

Conclusion

The findings indicate that inhibition elicited by aversive events is observed for word stimuli as well, and is most effective in the young.

Significance

The effect of valence during emotional word discrimination shows age-dependent differences reflected by ERPs.     

Schizotypal personality and vulnerability to involuntary autobiographical memories

Background and objectives

Individuals who score high on positive schizotypy personality traits are vulnerable to more frequent trauma-related intrusive memories after a stressful event. This vulnerability may be the product of a low level of contextual integration of non-stressful material combined with a heightened sensitivity to a further reduction in contextual integration during a stressful event. The current study assessed whether high scoring schizotypes are vulnerable to frequent involuntary autobiographical memories (IAMs) of non-stressful material.

Methods

A free-association word task was used. Participants completed three recorded trials which were then replayed to allow the identification of any associations where an involuntary autobiographical memory had come to mind. Self-report measures of schizotypy and anxiety were completed.

Results

All participants retrieved at least one IAM from the three free-association word trials, with 70% experiencing two or more IAMs. Individuals scoring high in schizotypy reported more IAMs than those who scored low. Over 75% of the memories retrieved were neutral or positive in content.

Limitations

The current study is an improvement on previous methodologies used to assess IAMs. However, bias due to retrospective recall remains a possibility.

Conclusions

Individuals scoring high in schizotypy are vulnerable to an increased level of neutral intrusive memories which may be associated with a ‘baseline’ level of information-processing which is low in contextual integration.     

Relation between emotional face memory and social anhedonia in schizophrenia

Background

There is an interest in investigating the relation between emotional memory impairments in schizophrenia and specific symptom dimensions. We explored potential links between emotional memory and social anhedonia severity in patients with schizophrenia and in healthy individuals.

Methods

Twenty-nine patients with schizophrenia and 27 matched healthy individuals completed the Chapman Revised Social Anhedonia Scale and then performed an emotional face recognition memory task involving happy, sad and neutral face expressions. We calculated emotional memory performance using 2 independent measures: the discrimination accuracy index Pr and the response bias Br. We also measured valence ratings of the face stimuli. We performed correlation analyses using the inter-individual variability in social anhedonia severity and the individual score obtained for each memory performance variable and for each face valence rating condition.

Results

Patients with schizophrenia reported higher levels of social anhedonia compared with healthy individuals. They also showed lower recognition accuracy for faces compared with healthy participants. We found no significant correlation between social anhedonia severity and any of the memory performance variables for both patients with schizophrenia and healthy individuals. Regarding potential links between social anhedonia severity and face valence ratings, we found that individuals with elevated social anhedonia had a tendency to rate the face stimuli as more negative.

Limitations

Our negative finding may be partly explained by a lack of statistical power owing to our small patient sample. In addition, our patient sample had unusually high estimated IQ scores, which highlights potential issues regarding the generalization of our findings. Finally, we used a yes–no recognition memory task with a very short retention interval delay.

Conclusion

Our results suggest that social anhedonia is not directly linked to emotional memory deficits and biases and does not interfere with the modulatory effect of positively valenced emotion on memory.     

Schizotypy and emotional memory

Background

Emotional dysfunction is a core feature of psychotic disorders. One expression of such dysfunction is a reduction of the emotion-induced enhancement of memory which is normally found in healthy individuals. Less severe disruption of emotional processing may also be present in individuals prone to ‘unusual’ psychosis-like experiences. In this study we investigate voluntary declarative (i.e. explicit or episodic) emotional memory performance, primarily in relation to positive schizotypy (as measured by the unusual experiences scale of the O-LIFE). The effect of negative schizotypy (introvertive anhedonia scale of the O-LIFE) was also explored. We hypothesized that schizotypal individuals (scoring highly on Unusual Experiences) would show reduced memory enhancement.

Methods

One hundred and two healthy participants viewed a narrated slide-show containing neutral and negative emotional content. They rated the story on a number of affective dimensions and completed a variety of trait measures, including a multi-dimensional measure of schizotypy. Seven days later, a memory test was performed and frequency of involuntary memories related to the slide-show assessed.

Results

The voluntary declarative emotional memory advantage in recall seen in low scorers (25%ile) on unusual experiences was absent in high scorers (75%ile), despite greater subjective fearfulness and emotionality in that group. However, the high scoring group did report experiencing more involuntary memories related to the story. There was no effect of negative schizotypy on declarative emotional memory.

Conclusions

The emotional memory difficulties seen in studies of schizophrenia may extend to those with a vulnerability to positive psychosis-like experiences. This vulnerability may be expressed in both voluntary declarative – as well as involuntary – emotional memory performance.     

Exploring the cognitive load of negative thinking: A novel dual-task experiment

Background and Objectives

Females are more likely to engage in the preoccupation of past negative experiences than males, which might contribute to their greater tendency toward depression. However, there is limited understanding regarding the cognitive basis for the negative autobiographical information processing of females. In the present study, we assessed the cognitive resources required for negative thinking, by using a novel dual-task paradigm that combined think-aloud and time-estimation tasks.

Methods

Fifty-three Japanese undergraduate students were asked to think aloud about personal past or future emotional episodes for a particular duration. In addition, they were asked to estimate the duration of their speech. Their estimates were compared to the actual time taken, and the errors were used as indices of cognitive burden during the speech task.

Results

As compared to males, females exhibited greater judgment errors, particularly when thinking about their past negative experiences. This suggests that females allocate more attentional resources toward thinking about the past.

Limitations

Participants could rehearse the task during the time reproduction phase, and the quality of the rehearsal and their memory capacity might have influenced the accuracy of their duration judgment.

Conclusions

Females tend to allocate more attentional resources than males to thinking about past negative episodes, which in turn might be associated with reduced availability of resources for central cognitive control processes such as inhibition of and switching away from processing of negative autobiographical information.     

Reducing vividness and emotional intensity of recurrent "flashforwards" by taxing working memory: an analogue study

Several studies have found that making eye movements while retrieving visual images about past negative events reduces their vividness and emotional intensity. A working memory account states that eye movements tax working memory and interfere with visual imagery, thus degrading images. This study examined whether eye movements also affect recurrent, intrusive visual images about potential future catastrophes (“flashforwards”) in a sample of female undergraduates who had indicated on a screening-scale that they suffer from such intrusions. They were asked to recall two intrusive images with or without making eye movements. Before and after each condition, participants retrieved the image, and rated its vividness and emotionality. Results showed that vividness of intrusive images was lower after recall with eye movement, relative to recall only, and there was a similar trend for emotionality. Potential implications are discussed.     

Activation of working memory in patients at the earliest stage of multiple sclerosis—An fMRI study

Objective

Previous fMRI studies on activation of working memory in multiple sclerosis (MS) patients presented heterogeneous results. Patients were reported to have altered brain activation patterns either in typical working memory circuits or in other brain regions even if they did not have any cognitive impairment according to the test batteries. We hypothesized that brain activation patterns in patients at a very early stage of the disease at very low EDSS-Score would not differ from healthy subjects.

Methods

We examined 13 patients at an early stage of MS matched with 13 healthy controls with a detailed psychometric test battery and an fMRI working memory paradigm.

Results

Patients and healthy controls did not differ in psychometric test batteries. In both groups those cortex areas typically involved in working memory processes like dorso-lateral prefrontal (DLPFC), ventro-lateral-prefrontal (VLPFC), fronto-medial and parietal cortex areas (Brodmann 6, 7, 8, 9, 10, 32, 40, 45, 46, 47) were equally activated.

Conclusion

In contrast to former studies we found no differences in activation patterns in the fMRI scanning measuring working memory tasks between psychometrically tested homogenous groups of patients in early stages of MS and control subjects.     

Infant febrile seizures: Changes in declarative memory as revealed by event-related potentials

Objective

According to a widespread opinion the vast majority of infant febrile seizures (IFS) are harmless. However, IFS are often associated with hippocampal sclerosis, which should lead to deficient episodic memory with spared context-free semantic memories. Although IFS represent the most common convulsive disorder in children, these consequences are rarely examined.

Methods

We measured the hippocampal volume of 17 IFS children (7–9 years old) and an age-matched control group on the basis of MR images. Furthermore, we examined episodic and semantic memory performance with standardized neuropsychological tests. Two processes underlying recognition memory, namely familiarity and recollection, were assessed by means of event-related potentials (ERP).

Results

The IFS children did not show a decreased hippocampus volume. Intelligence, working memory, semantic and episodic memory were intact. However, ERP indices of recognition memory subprocesses revealed deficits in recollection-based remembering that presumably relies on the integrity of the hippocampus, whereas familiarity-based remembering seemed to be intact.

Conclusions

Although hippocampus volume remains unaffected, IFS seems to induce functional changes in the MTL memory network, characterized by a compensation of recollection by familiarity-based remembering.

Significance

This study significantly adds to the debate on the consequences of IFS by differentiating the impact on memory processing.     

Effect of continuous positive airway pressure treatment on short-term memory performance over 24 h of sustained wakefulness in patients with obstructive sleep apnea–hypopnea syndrome

Background

Few studies have examined the impact of continuous positive airway pressure (CPAP) therapy on short-term memory (STM) over sustained wakefulness in patients with obstructive sleep apnea–hypopnea syndrome (OSAHS). We have investigated if impaired STM can be reversed by CPAP treatment in a 24-h sustained wakefulness paradigm.

Methods

Our follow-up study was conducted with repeated-memory tasks within 12 OSAHS patients and 10 healthy controls who underwent three 32-h sessions, one before CPAP (T0) and the second (T3) and the third (T6), after 3 and 6 months of treatment, respectively, for OSAHS patients. Each session included one night of sleep followed by 24 h of sustained wakefulness, during which both groups performed STM tasks including both digit span (DS) and Sternberg tasks.

Results

Untreated OSAHS patients had no deficit in the forward DS task measuring immediate memory but were impaired in STM, especially working memory assessed by the complex Sternberg task and the backward DS. However, only performance in the latter was improved after 6 months of CPAP treatment.

Conclusions

Because the high level of memory scanning required high speed in information processing, persistent impairment on the complex Sternberg task may be attributable to working memory slowing, possibly enhanced by sustained wakefulness.     

Emotional distress and pain tolerance in obsessive-compulsive disorder

Background and objectives

Physical pain can reduce emotional distress, perhaps especially the psychic pain of guilt. This implies that people who continually experience guilt may exhibit greater tolerance for pain relative to people who do not.

Methods

To test this hypothesis, we administered a pressure algometer procedure to assess pain tolerance in patients with obsessive-compulsive disorder (OCD) plagued by moral obsessions (e.g., concerns about harming others, violating religious values), in patients with OCD with non-moral obsessions (e.g., regarding contamination and symmetry), and in healthy comparison subjects.

Results

The results indicated that the OCD groups did not differ in levels of guilt, emotional distress tolerance, or in pain endurance. However, when we collapsed across subtypes, OCD subjects endured pain significantly longer than did healthy subjects.

Limitations

Limitations included small sample size and use of a sample with complex OCD symptoms that were, in some instances, difficult to categorize.

Conclusions

The results suggest that individuals with severe OCD might be willing to endure physical pain as a distraction from emotional distress, an expression of negative self-worth, or as a means to gain control over some aspect of suffering.     

Neural correlates of the individual emotional Stroop in borderline personality disorder

Objective

Emotional dysregulation is a key feature of borderline personality disorder (BPD) with altered inhibitory functions having suggested as being crucial. The anterior cingulate cortex and further prefrontal brain regions are crucial for response inhibition. The regulation of emotions is ensured via inhibitory control over the amygdala. The present study aimed to investigate neural correlates of response inhibition in BPD by using an emotional Stroop paradigm extending the task to word stimuli which were related to stressful life events.

Methods

Twenty BPD patients and 20 healthy controls underwent functional magnetic resonance imaging (fMRI) while performing the individual emotional Stroop task. A block design was used with the following word type conditions: neutral words, general negative words, and individual negative words. The individual negative words were recruited from a prior interview conducted with each participant.

Results

While BPD patients had overall slower reaction times in the Stroop task compared to healthy controls, there was no increased slowing with emotional interference. Controls exhibited significant fMRI blood oxygenation level-dependent signal increases in the anterior cingulate cortex as well as in frontal cortex contrasting generally negative vs. neutral and individual negative vs. neutral conditions, respectively. BPD patients did not show equivalent signal changes.

Conclusions

These results provide further evidence for a dysfunctional network of brain areas in BPD, including the ACC and frontal brain regions. These areas are crucial for the regulation of stress and emotions, the core problems of BPD patients.     

Evaluación ecológica en el deterioro cognitivo leve y enfermedad de Alzheimer mediante el Rivermead Behavioural Memory Test

Introduction

The Rivermead Behavioural Memory Test (RBMT) is a short, ecologically-valid memory test battery that can provide data about a subject's memory function in daily life. We used RBMT to examine daily memory function in patients with mild cognitive impairment (MCI), Alzheimer disease (AD), and in healthy controls. We also evaluated differences between the memory profiles of subjects whose MCI remained stable after 1 year and those with conversion to AD.

Patients and methods

Sample of 91 subjects older than 60 years: 30 controls, 27 MCI subjects and 34 AD patients. Subjects were assessed using MMSE and RBMT.

Results

The 40 men and 51 women in the sample had a mean age of 74.29 ± 6.71 and 5.87 ± 2.93 years of education. For the total profile and screening RBMT scores (P<.001) and total MMSE scores (P<.05), control subjects scored significantly higher than those with MCI, who in turn scored higher than AD patients. In all subtests, the control group (P<.001) and MCI group (P<.05) were distinguishable from the AD group. Prospective, retrospective, and orientation subtests found differences between the MCI and control groups (P<.05). MCI subjects who progressed to AD scored lower at baseline on the total RBMT and MMSE, and on name recall, belongings, story − immediate recall, route − delayed recall, orientation (P<.05), face recognition, story − delayed recall, and messages − delayed recall sections (P<.01).

Conclusions

RBMT is an ecologically-valid episodic memory test that can be used to differentiate between controls, MCI subjects, and AD subjects. It can also be used to detect patients with MCI who will experience progression to AD.     

An informational pathway to the development of a contamination-related memory bias

Background and objectives

Following from previous research in which post-encoding suggestions of threat led to the development of a memory bias (in the presumed absence of an attentional bias; Senn & Radomsky, 2012), we sought to examine whether the development of a similar threat-relevant memory bias could be fostered via a purely informational pathway.

Methods

A vignette about a classroom interaction was read aloud to (n = 96) undergraduate participants who then completed a post-encoding recall test. Participants were told that the experimenter forgot to read the last sentence of the vignette, and were then randomly assigned either to the Threat condition, in which the additional statement indicated that a character in the vignette had a highly contagious flu, or to the No-Threat condition, in which the additional statement indicated that a character in the vignette had been accepted to graduate school. A second recall test was then administered.

Results

Participants in the Threat condition (but not those in the No-Threat condition) demonstrated aproportionate memory bias in favor of threatening information. This bias was not evident at the initial recall test.

Limitations

Time spent engaging in active recall was not assessed. Also, although the study was designed to minimize demand characteristics, it is possible that these played a role.

Conclusions

An explicit memory bias for threat can be created through informational means alone, even when no threat was present at encoding. Results are discussed in terms of pathways to fear and of cognitive approaches to understanding and treating anxiety disorders.     

Overgeneral memory in asylum seekers and refugees

Background and objectives

Studies in western samples have shown that post-traumatic stress disorder (PTSD) and depression are associated with overgeneral autobiographical memory retrieval. This study assesses whether this association extends to asylum seekers and refugees from diverse cultural backgrounds. We discuss implications for those providing testimony of their experiences when seeking asylum.

Method

38 asylum seekers and refugees were recruited through clinics and community groups. Clinical interviews assessed PTSD and depression and participants completed a test of autobiographical memory specificity.

Results

When accounting for omissions, participants with PTSD and depression recalled a lower proportion of specific memories. Those with PTSD also failed more frequently to report any memory.

Limitations

The sample did not permit separate evaluation of the effects of PTSD and depression on specificity.

Conclusions

Lower memory specificity observed in people experiencing PTSD and depression in western populations extends to asylum seekers and refugees from diverse cultural backgrounds. This study adds to the literature suggesting that being recognised as a refugee fleeing persecution is more difficult for those with post-traumatic symptoms and depression.     

Apathy,poor verbal memory and male gender predict lower psychosocial functioning one year after the first treatment of psychosis

Background

Apathy is a negative symptom associated with poor psychosocial functioning in schizophrenia but has not been sufficiently studied as predictor of poor functioning in first episode psychosis (FEP).

Objective

The main aim of the current study was to evaluate if apathy predicts poor functioning after 1 year in FEP patients in the context of other clinical variables with influence on outcome.

Method

Sixty-four FEP patients completed an extensive clinical and neuro-psychological test battery at baseline and 1-year follow-up. Symptoms were assessed with the Positive and Negative Syndrome scale (PANSS), apathy with the shortened Apathy Evaluation Scale (AES-C-12) and psychosocial functioning with the functioning score from the split version of the Global Assessment of Functioning scale (GAF-F).

Results

High levels of apathy, poor verbal memory and being male were the baseline variables that best predicted poor functioning at 1-year follow-up, explaining 34% of the variance in GAF-F. When PANSS negative factor was included in the analysis, the significance of AES-C-12 diminished.

Conclusion

These findings points to a robust role for apathy among the negative symptoms in the development of persisting psychosocial dysfunction in FEP and supports the current effort in targeting motivation to improve functioning.     

Effect of task-irrelevant high-speed verbal stimulation on a visual/verbal word-discrimination task: An event-related potential study

Objectives

We investigated whether incomprehensible high-speed auditory speech stimulation was processed and interacted with visual-word discrimination processing. We hypothesised that an interaction might indicate the capacity of working memory (WM) to perform the temporal processing of auditory verbal information.

Methods

We recorded P300 for a visual-word discrimination Oddball paradigm in 14 healthy subjects. Auditory speech and reversed speech stimulation were presented at various speeds as task-irrelevant stimuli during the P300 tasks.

Results

The P300 latency was prolonged under forward high-speed speech stimuli (×2.5 and ×3.5) compared with the standard speed and white noise, but there was no effect of reversed speech stimuli on the P300 latency during the word-discrimination paradigm.

Conclusions

We considered that high-speed speech stimulation was processed without conscious comprehension and competed with verbal processing during the visual-word-discrimination task, possibly by interfering with the use of WM.

Significance

The present study shows the capacity of the brain to process high-speed verbal stimulation and the interaction with a visual-verbal task.