| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
CASE REPORT |
From the Department of Psychological Medicine (R.A.A.K., S.C.W.), Section of Cognitive Neuropsychiatry (R.A.A.K., A.S.D.), and Department of Health Services Research (T.K.J.C.), King's College London, Institute of Psychiatry, London, United Kingdom.
Address correspondence and reprint requests to DrA. Kanaan, Institute of Psychiatry, Psychological Medicine, P062, WEC, Denmark Hill, London SE5 9RJ. E-mail: r.kanaan{at}iop.kcl.ac.uk
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONNOTESREFERENCES |
|---|
Methods: Single case study of a 37-year-old woman with clinically repressed recall and unexplained right-sided paralysis. We describe the application of the Life Events and Difficulties Schedule (LEDS) to her history, and a novel functional magnetic resonance imaging (fMRI) procedure exploring emotion processing of traumatic and control memories.
Results: While in the scanner, cued recall of the clinically repressed event was associated with regional brain activations characteristic of emotional arousal, including the amygdala and right inferior frontal lobe, when compared with an equally severe event from the patient's past, as rated by the LEDS. Such recall was also associated with decreased motor activity in the area corresponding to the subjectively paralyzed limb.
Conclusion: This case study provides neuroimaging evidence for a connection between traumatic events and ongoing neurological symptoms.
Key Words: conversion • dissociative • repressed • fMRI • paralysis • memory
Abbreviations: CT = computerized tomography; MRI = magnetic resonance imaging; EEG = Electroencephalogram; ICD = International Classification of Diseases; fMRI = functional magnetic resonance imaging; LEDS = Life Events & Difficulties Schedule; mg = milligrams; BA = Brodmann area; T = Tesla; BOLD = Blood Oxygen Level Dependent; TR = Time to repeat.
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONNOTESREFERENCES |
|---|
We describe a patient with prototypical emotional repression and motor conversion. In addition to the usual investigations and multi-disciplinary management, we describe the use of the Life Events & Difficulties Schedule (LEDS) (7) to provide more objective ratings of her life events, and a novel use of fMRI to elucidate the processing of the emotional events relevant to her neurological symptoms.
|
METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONNOTESREFERENCES |
|---|
In her history, she reported that she had been born 6-weeks prematurely, but had developed normally thereafter. She had a disrupted family life, being raised in various care homes from the age of 4, and suffered sexual abuse. Her father was imprisoned when she was a child and subsequent disturbance in her behavior led to her seeing a child psychologist for one month. As an adolescent, she had some contact with the justice system. She also had a history of deliberate self harm. At 27, in the context of relationship difficulties, she took an overdose of paracetamol but received no psychiatric follow-up. She held a number of unskilled jobs, including most recently as a delivery driver. Her family history is notable for epilepsy in a sibling.
She was referred to our neuropsychiatry service, where a diagnosis of mixed dissociative (conversion) disorder was made, according to ICD-10 criteria (8) and admission recommended. In the intervening period, she spontaneously recovered motor power in her leg, though her arm remained weak, with 0/5 power. She had several recurrences of her seizures, in which witnesses reported she lost consciousness, shook on the left side of her body, and was unable to speak for several days afterward. She commenced anti-depressant treatment (amitriptyline 50 mg nocte) to help her sleep.
She was admitted to the Lishman Unit at the Maudsley (psychiatric) Hospital in August 2005. She received multi-disciplinary treatment from physiotherapy, cognitive-behavioral therapy, and psychiatry. Her amitriptyline was increased to 100 mg, for low mood, though this did not meet the criteria for a depressive episode. She also underwent the further investigation of her blood tests (including a normal post-seizure prolactin), a normal sleep EEG, and normal nerve-conduction studies (including transcranial magnetic stimulation, which evoked muscular twitches in her affected limbs by cortical stimulation). She underwent neuropsychological assessment, which found her to be functioning below her predicted premorbid level, in the average/low-average range, with a particular difficulty with abstract reasoning. She also underwent the fMRI investigation of her relevant traumatic experiences, as described below. After 6 weeks she was discharged with significant improvement in all her symptoms, though with some residual weakness in her right hand.
Life Events Assessment and fMRI Scanning
She was interviewed at length, focusing on the 3 months preceding the onset of her symptoms, to identify potentially stressful life events. These events were then rated using the LEDS (7). This is a highly reliable, validated measure that significantly overcomes the problems of recall and interviewer bias that operate when probing past events. The LEDS employs a recorded, extensive semi-structured interview to detect events, and the creation of a narrative of each life event or difficulty. These narratives are given to a panel, blind to diagnosis, which provides an external, consensus rating of severity that reflects how the ‘average' person might regard the event taking account of the wider contextual circumstances. Two adverse life events were identified—her daughter's attempted suicide, and her partner's announcement that he was leaving her—both of which scored the highest rating of severity on the LEDS. Clinically, the latter event was readily identifiable as crucial to the genesis of her symptoms, both by its immediate temporal antecedence, and by the potential secondary gain that it accrued (preventing, or at least delaying, her partner's leaving). Subjectively, her report of these events was equally characteristic: she described her daughter's suicide attempt as a harrowing experience, but, in marked contrast to the severity assigned by the LEDS, claimed that her partner's announced intention was not at all distressing. Consequently, though receptive to psychological explanations, she did not feel that her partner's announcement was important—consistent with a model of emotional repression.
Based on this interview, adapting the technique of Maguire & Mummery (9), we created a set of auditory probes for use in the fMRI scanner. Twenty-four length-matched statements were recorded for each of the two adverse events, and for a nonstressful (lowest rating on the LEDS) control event from the same epoch (a weekend visit to her sister). One quarter of these were changed to make them false. For example, she recalled having to break into her daughter's room during the overdose: her statement "It was easy to kick the door down" was changed to "It was hard to kick the door down". Maguire & Mummery found that in correctly identifying the truth or falsity of the statements' subjects had to vividly recall the events.
The probes were presented auditorily to her while in a neuro-optimized 1.5T GE MRI scanner. Statements were presented in blocks of eight from each event, using a counterbalanced design to facilitate recall and minimize the overlap of affective response between events. Before each block of eight, a word identifying the next block ("weekend", "overdose" or "break-up") was presented visually for eight seconds, via a reflector system. The block of statements was then played, taking up to four seconds per statement, and she was given seven seconds after each to respond true or false with a button press of her left hand, while T2* images were acquired (TR 3.1s; 38 x 3 mm slices, 0.3 mm gap). The total scanning time was 14 minutes 20 seconds. Images were processed using XBAM_v3.4, a fMRI analysis software package written at the Institute of Psychiatry in London. Data were first processed to minimize motion related artifacts, and then smoothed with a 7.2 mm Gaussian filter. The experimental model was fitted to the time series and a goodness-of-fit statistic computed at each voxel. The permutation of this statistic generates a null distribution under the assumption of no experimentally-determined response. The observed and permuted test statistic maps were then transformed into standard space using a two-stage warping procedure. Analyses of variance (ANOVAs) were carried out on the test-statistic maps by computing the between-condition differences at each voxel in standard space. The probability of this difference under the null hypothesis was inferred by reference to the permuted null distribution, tested at the cluster level. See http://brainmap.co.uk for full details.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONNOTESREFERENCES |
|---|
2 = 2.4, df = 2, p = .3) or reaction times (Kruskal-Wallis, p = .8) between the three events. The analysis of the fMRI scans showed a consistent pattern between conditions (at voxel and cluster thresholds of p < .05). The ‘break-up' condition showed greater activation than both the ‘neutral' and the ‘overdose' conditions, in the right medial temporal lobe (Talairach coordinates 22,–15,–20, p = .015) extending to the amygdala (see Figure 1), the right inferior frontal lobe (Brodmann area (BA) 46), the right parietal lobe, and the cingulate gyrus/ premotor area (BA 32/6). It showed a large relative de-activation in the left primary motor cortex (BA 4), in the area corresponding to the affected right upper limb, when compared with the ‘overdose' condition (Talairach coordinates –25,–4,56, p = .003; see Figure 2).
|
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONNOTESREFERENCES |
|---|
The recall of emotional events activates a network centered on the amygdalae and the right inferior frontal cortex (10). Intact amygdalae are necessary for vivid emotional recall (11), and amygdala activation, both at encoding (12) and at retrieval (13), correlates with successful recall of emotional events. The patient had no recall deficit with regards to the key event—in fact she made (nonsignificantly) fewer recall errors than with the subjectively more emotional event—but she did deny that she found the key event emotionally salient, in apparent conflict with her functional activation. One interpretation of this activation is suggested by the role of the amygdala in emotional recall, namely that the ‘break-up' event was more emotionally salient than the ‘overdose' (or the neutral event), and this would concord with the dramatic symptoms the ‘break-up' event appeared to produce. This would be consistent with dissociation, in the sense that the emotional experience may have been processed at a physiological level but apparently cut-off from phenomenal awareness. However, functional neuroimaging studies of dissociation, and of memory suppression, suggest these processes require prefrontal activation, presumed to reflect inhibition of memories and emotional salience as reflected in hippocampal (6) and amygdala (14) deactivation, respectively. The results can also be understood in terms of the separation of semantic from episodic memory proposed by Kihlstrom (15), and by theories of emotion which separate the labeling, based on social and cognitive cues, from the felt experience of emotion (16).
|
NOTES |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONNOTESREFERENCES |
|---|
DOI:10.1097/PSY.0b013e31802e4297
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONNOTESREFERENCES |
|---|
This article has been cited by other articles:
 |
|
 |
|
  V. Voon, C. Gallea, N. Hattori, M. Bruno, V. Ekanayake, and M. Hallett The involuntary nature of conversion disorder Neurology, January 19, 2010; 74(3): 223 - 228. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A Abbass, D Lovas, and A Purdy Direct Diagnosis and Management of Emotional Factors in Chronic Headache Patients Cephalalgia, December 1, 2008; 28(12): 1305 - 1314. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Stone, A. Zeman, E. Simonotto, M. Meyer, R. Azuma, S. Flett, and M. Sharpe fMRI in Patients With Motor Conversion Symptoms and Controls With Simulated Weakness Psychosom Med, November 1, 2007; 69(9): 961 - 969. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
