DEPERSONALIZATION IN TEMPORAL LOBE EPILEPSY AND THE ORGANIC PSYCHOSES

Altered Sense of Body Ownership and Agency in Posttraumatic Stress Disorder and Its Dissociative Subtype: A Rubber Hand Illusion Study

Traumatic experiences have been linked to the development of altered states of consciousness affecting bodily perception, including alterations in body ownership and in sense of agency, the conscious experience of the body as one's own and under voluntary control. Severe psychological trauma and prolonged distress may lead to posttraumatic stress disorder (PTSD). Together, symptoms of derealization and, related specifically to the sense of body ownership and agency, of depersonalization (where parts of the body or the entire body itself is perceived as detached and out of control), constitute the dissociative subtype (PTSD+DS). In this study, we explored the Rubber Hand Illusion, an experimental paradigm utilized to manipulate sense of body ownership in PTSD (n = 4) and PTSD+DS (n = 6) as compared to healthy controls (n = 7). Perceived finger location and self-report questionnaires were used as behavioral and subjective measures of the illusion, respectively. In addition, the correlation between the illusion's effect and sense of agency as a continuous feeling of controlling one's own body movements was explored. Here, a lower illusion effect was observed in the PTSD as compared to the control group after synchronous stimulation for both the proprioceptive drift and subjectively perceived illusion. Moreover, by both proprioceptive drift and by subjective ratings, the PTSD+DS group showed a response characterized by high variance, ranging from a very strong to a very weak effect of the illusion. Finally, sense of agency showed a trend toward a negative correlation with the strength of the illusion as subjectively perceived by participants with PTSD and PTSD+DS. These findings suggest individuals with PTSD may, at times, maintain a rigid representation of the body as an avoidance strategy, with top-down cognitive processes weakening the impact of manipulation of body ownership. By contrast, the response elicited in PTSD+DS appeared to be driven by either an increased vulnerability to manipulation of embodiment or by a dominant top-down cognitive representation of the body, with disruption of multisensory integration processes likely in both cases. Taken together, these findings further our understanding of bodily consciousness in PTSD and its dissociative subtype and highlight the supportive role played by sense of agency for the maintenance of body ownership.

Relation between patterns of intrinsic network connectivity, cognitive functioning, and symptom presentation in trauma-exposed patients with major depressive disorder

OBJECTIVE

The present study investigated resting fMRI connectivity within the default mode (DMN), salience (SN), and central executive (CEN) networks in relation to neurocognitive performance and symptom severity in trauma-exposed patients with major depressive disorder (MDD).

METHOD

Group independent component analysis was conducted among patients with MDD (n = 21), examining DMN, SN, and CEN connectivity in relation to neurocognitive performance and symptom severity. Activation in these networks was also compared between the patient group and healthy controls (n = 20).

RESULTS

Among the patient group, higher levels of performance on measures of verbal memory and executive functioning were related to increased connectivity within the DMN (i.e., inferior parietal lobe; precuneus). Greater depression severity was related to reduced connectivity between the SN and a node of the DMN (i.e., posterior cingulate cortex) and higher depersonalization symptoms were related to enhanced connectivity between the SN and a node of the DMN (i.e., middle temporal gyrus). Higher symptoms of depersonalization were also associated with reduced integration of the DMN with the medial frontal gyrus. Relative to controls, patients with MDD showed greater connectivity of the ventromedial prefrontal cortex within the DMN.

CONCLUSION

Intrinsic connectivity network patterns are related to cognitive performance and symptom presentation among trauma-exposed patients with MDD.

"I can't tell whether it's my hand": a pilot study of the neurophenomenology of body representation during the rubber hand illusion in trauma-related disorders

BACKGROUND

Early traumatic experiences are thought to be causal factors in the development of trauma-related dissociative experiences, including depersonalization and derealization. The rubber hand illusion (RHI), a well-known paradigm that measures multi-sensorial integration of a rubber hand into one's own body representation, has been used to investigate alterations in the experience of body ownership and of body representation. Critically, however, it has never been studied in individuals with trauma-related disorders.

OBJECTIVE

To investigate body representation distortions occurring in trauma-related disorders in response to the RHI.

METHOD

The RHI was administered to three individuals with the dissociative subtype of posttraumatic stress disorder (PTSD), and subjective, behavioral, cardiovascular and skin conductance responses were recorded.

RESULTS

Participants' subjective experiences of the RHI were differentiated and complex. The illusion was induced following both synchronous and asynchronous brushing and variably evoked subjective distress, depersonalization and derealization experiences, tonic immobility, increased physiological arousal and flashbacks.

CONCLUSIONS

The present findings point towards the RHI as a strong provocation stimulus that elicits individual patterns of symptom presentation, including experiences of distress and dissociation, in individuals with trauma-related disorders, including the dissociative subtype of PTSD.

HIGHLIGHTS OF THE ARTICLE

The rubber hand illusion (RHI) elicits distress, tonic immobility, depersonalization and derealization, and autonomic responses in individuals with trauma-related disorders, including the dissociative subtype of posttraumatic stress disorder (PTSD). RHI effects related to body misrepresentation may trigger altered experiences related to body ownership. The RHI represents a promising paradigm for studying the neurophenomenology of body distortion in individuals experiencing trauma-related altered states of consciousness (TRASC).

Dissociative symptoms and epilepsy

This article considers the relationship between various types of dissociative symptoms, including symptoms of depersonalization, derealization, and conversion disorders, and epilepsy. After introductory remarks concerning dissociation, this relationship is discussed through two main themes: firstly, the phenomenology and mechanisms of so-called 'dreamy states' in epilepsy and their closest analogs in psychiatric disorders, and secondly, the similarities and differences between epileptic seizures and psychogenic nonepileptic attacks. Although epileptic and dissociative symptoms may appear similar to observers, they arise through different mechanisms and have different experiential qualities.

Epilepsy-induced behavioral changes during the ictal phase

In epilepsy, experiential phenomena and behavioral manifestations may pose a number of problems in terms of differential diagnosis. From a clinical point of view, ictal psychiatric symptoms represent partial seizures, mainly partial ones. In the majority of cases, they are very brief (lasting from a few seconds to a few minutes), stereotyped, out of context, and frequently associated with subtle or overt automatisms and postictal confusion of variable duration. In some cases, such symptoms are followed by alteration of consciousness as the ictus evolves to a complex partial seizure or a generalized tonic-clonic seizure. This paper reviews clinically relevant behavioral patterns during seizures discussing clinical phenomenology and relevance in terms of lateralizing value.

Is the Charcot and Bernard case (1883) of loss of visual imagery really based on neurological impairment?

INTRODUCTION. The Charcot and Bernard case of visual imagery, Monsieur X, is a classic case in the history of neuropsychology. Published in 1883, it has been considered the first case of visual imagery loss due to brain injury. Also in recent times a neurological valence has been given to it. However, the presence of analogous cases of loss of visual imagery in the psychiatric field have led us to hypothesise functional origins rather than organic. METHODS. In order to assess the validity of such an inference, we have compared the symptomatology of Monsieur X with that found in cases of loss of visual mental images, both psychiatric and neurological, presented in literature. RESULTS. The clinical findings show strong assonances of the Monsieur X case with the symptoms manifested over time by the patients with functionally based loss of visual imagery. CONCLUSION. Although Monsieur X's damage was initially interpreted as neurological, reports of similar symptoms in the psychiatric field lead us to postulate a functional cause for his impairment as well.

Cognitive-affective neuroscience of depersonalization

Depersonalization disorder (DPD) is characterized by a subjective sense of detachment from one's own being and a sense of unreality. An examination of the psychobiology of depersonalization symptoms may be useful in understanding the cognitive-affective neuroscience of embodiment. DPD may be mediated by neurocircuitry and neurotransmitters involved in the integration of sensory processing and of the body schema, and in the mediation of emotional experience and the identification of feelings. For example, DPD has been found to involve autonomic blunting, deactivation of sub-cortical structures, and disturbances in molecular systems in such circuitry. An evolutionary perspective suggests that attenuation of emotional responses, mediated by deactivation of limbic structures, may sometimes be advantageous in response to inescapable stress.

A review of neuroimaging studies in PTSD: heterogeneity of response to symptom provocation

Different experiential, psychophysiological, and neurobiological responses to traumatic symptom provocation in posttraumatic stress disorder (PTSD) have been reported in the literature. Two subtypes of trauma response have been hypothesized, one characterized predominantly by hyperarousal and the other primarily dissociative, each one representing unique pathways to chronic stress-related psychopathology. Recent PTSD neuroimaging findings in our own laboratory support this notion and are consistent with the view that grouping all PTSD subjects, regardless of their different symptom patterns, in the same diagnostic category may interfere with our understanding of posttrauma psychopathology. This review will integrate findings of different experiential, psychophysiological, and neurobiological responses to traumatic symptom provocation with the clinical symptomatology and the neurobiology of PTSD.

Episodic depersonalization in focal epilepsy

In this report a patient with episodic depersonalization is described. As the depersonalization episodes had been attributed to partial seizures, this patient was treated with antiepileptic medication. However, clinical evaluation with long-term video/EEG revealed no evidence of seizure activity during the depersonalization episodes. On the other hand, further evaluation revealed findings that are frequently associated with focal epilepsy. In addition to episodic depersonalization, this patient had secondary generalized seizures. The relationship between episodic depersonalization, temporal lobe pathology, and epilepsy is discussed against the background of this case.

Brain activation during script-driven imagery induced dissociative responses in PTSD: a functional magnetic resonance imaging investigation

BACKGROUND

The goal of this study was to examine the neuronal circuitry underlying dissociative responses to traumatic script-driven imagery in sexual-abuse-related posttraumatic stress disorder (PTSD). Pilot studies in our laboratory have shown that PTSD patients had very different responses to traumatic script-driven imagery. Approximately 70% of patients relived their traumatic experience and showed an increase in heart rate while recalling the traumatic memory. The other 30% of patients had a dissociative response with no concomitant increase in heart rate. This article focuses on the latter group.

METHODS

The neuronal circuitry underlying dissociative responses in PTSD was studied using the traumatic script-driven symptom provocation paradigm adapted to functional magnetic resonance imaging (fMRI) at a 4 Tesla field strength in 7 subjects with sexual-abuse-related PTSD and 10 control subjects.

RESULTS

Compared with control subjects, PTSD patients in a dissociative state showed more activation in the superior and middle temporal gyri (BA 38), the inferior frontal gyrus (BA 47), the occipital lobe (BA 19), the parietal lobe (BA 7), the medial frontal gyrus (BA 10), the medial cortex (BA 9), and the anterior cingulate gyrus (BA 24 and 32).

CONCLUSIONS

These findings suggest that prefrontal and limbic structures underlie dissociative responses in PTSD. Differences observed clinically, psychophysiologically, and neurobiologically between patients who respond to traumatic script-driven imagery with dissociative versus nondissociative responses may suggest different neuronal mechanisms underlying these two distinct reactions.

Depersonalization disorder: thinking without feeling

Patients with depersonalization disorder (DP) experience a detachment from their own senses and surrounding events, as if they were outside observers. A particularly common symptom is emotional detachment from the surroundings. Using functional magnetic resonance imaging (fMRI), we compared neural responses to emotionally salient stimuli in DP patients, and in psychiatric and healthy control subjects. Six patients with DP, 10 with obsessive-compulsive disorder (OCD), and six volunteers were scanned whilst viewing standardized pictures of aversive and neutral scenes, matched for visual complexity. Pictures were then rated for emotional content. Both control groups rated aversive pictures as much more emotive, and demonstrated in response to these scenes significantly greater activation in regions important for disgust perception, the insula and occipito-temporal cortex, than DP patients (covarying for age, years of education and total extent of brain activation). In DP patients, aversive scenes activated the right ventral prefrontal cortex. The insula was activated only by neutral scenes in this group. Our findings indicate that a core phenomenon of depersonalization--absent subjective experience of emotion--is associated with reduced neural responses in emotion-sensitive regions, and increased responses in regions associated with emotion regulation.

Basal activity of the hypothalamic-pituitary-adrenal axis in patients with depersonalization disorder

Depersonalisation disorder may occur during severe anxiety or following a traumatic event, suggesting a possible role of stress hormones. This study investigated basal activity of the hypothalamic-pituitary-adrenal (HPA) axis in patients with depersonalisation disorder. Salivary cortisol levels were measured at four time points over 12 h in patients with depersonalisation disorder (N=13), major depressive disorder (MDD, N=14) and healthy controls (N=13). Beck Depression Inventory scores were significantly higher in depersonalised subjects than controls, while MDD subjects demonstrated higher scores than both groups. Basal cortisol levels of depersonalised subjects were significantly lower than those of MDD subjects but not healthy controls. These results point to reduced basal activity of the HPA axis in depersonalisation disorder. This pilot study supports the distinction between depersonalisation disorder and major depressive disorder which should be examined in a larger sample.

Primary and secondary depersonalisation disorder: a psychometric study

INTRODUCTION

Depersonalisation may be part of a symptom-complex, a primary or a secondary disorder. Optimal methods of measurement and diagnosis have not been established.

METHODS

We assessed 42 patients with primary or secondary depersonalisation, plus psychiatric and non-psychiatric controls using a variety of self-report questionnaire scales including the Beck depression and anxiety Inventories, and one developed by the authors (the Fewtrell Depersonalisation Scale (FDS)). The correlations between the scales and measures of anxiety and depression were calculated, as were sensitivity and specificity against an operational case definition.

RESULTS

All the scales were highly correlated. All could distinguish depersonalisation cases from the rest but none could distinguish between primary and secondary depersonalisation disorder. Anxiety and especially depression were correlated with depersonalisation symptoms. The FDS had high sensitivity (85.7%) and specificity (92.3%) which compared favourably with other instruments. Patients with both derealisation and depersonalisation scored the highest on the FDS.

DISCUSSION

Depersonalisation disorder comprises a measurable cluster of symptoms which may be quantified with the help of self-report scales. Primary and secondary forms overlap, with depressed mood a frequent feature.

Neuropsychiatric manifestations of right hemisphere lesions

A wide variety of neuropsychiatric syndromes are associated with right brain dysfunction, including mania, depression, psychosis, hallucinations, personality changes, anxiety, dissociative states, and altered sexual behavior. This review summarizes the anatomic relationships reported between specific neuropsychiatric syndromes and localized right brain lesions. Information is derived from individual case studies and case series. Most neuropsychiatric syndromes are found to be associated with damage to the limbic system. Disruption of body schema and interpersonal functions mediated primarily by the right hemisphere contributes to the neuropsychiatric disability associated with right hemisphere injury. Nonlesion biologic and sociocultural influences including a family history of psychiatric disorder, personal psychiatric history, and the presence of cerebral atrophy increase the vulnerability to neuropsychiatric morbidity following right brain damage. Investigation of the secondary neuropsychiatric disorders occurring with right brain dysfunction contributes to understanding the pathophysiology of idiopathic psychiatric syndromes.

Depersonalization in a group of normal subjects

There have been relatively few studies concerning the occurrence of depersonalization phenomena in normal subjects. Roberts (1960) and Dixon (1963) studied college students and reported a high incidence of brief depersonalization experiences in their samples. The aim of the present study is to investigate the relationship between depersonalization, the conditions under which it occurred and a measure of extraversion/ introversion in a group of normal subjects.