Conversion Paralysis Research Articles

A psychogenic unilateral ptosis: The interest of a multidisciplinary management

Psychogenic ptosis or pseudoptosis is a rare presentation of motor conversion disorder. We report a case study of patient with a left atypical ptosis diagnosed “conversion disorder” and who has been treated in our physical medicine and rehabilitation department. A 40-year-old woman was presented with a left atypical ptosis. The symptomatology has associated muscle spasm of orbicular oculi, inability to elevate eyebrow, photophobia and ipsilateral hemiface pain. Neurologists have diagnosed “pseudoptosis”. Psychiatrists have confirmed psychogenic origin of the symptoms and have diagnosed “pseudoptosis secondary to conversion disorder”. Therapeutic management has been early and multidisciplinary. In our department of physical medicine and rehabilitation, the patient has been treated by electrotherapy. In psychiatry, the patient has been treated by drugs and by psychotherapy. All symptoms were disappeared after six months of treatment. Conversion disorders designate some unexplained neurological symptoms (motor, sensory, epileptoid), influenced by psychological factors. Paralysis is the most common symptom of conversion disorder. It reproduces all forms of organic paralyses. Paralysis of eyelid lifting muscle (ptosis) is an uncommon conversion paralysis. Clinically, it manifests by muscle spasm of orbicular oculi, inability to elevate eyebrow and photophobia. Early multidisciplinary management which combines neurology, psychiatry, physical medicine and rehabilitation, optimize evolution of patients. All symptoms of the woman have disappeared after an early and multidisciplinary treatment involving physical medicine and rehabilitation and psychiatry.

Conversion paralysis after cervical spine arthroplasty: A case report and literature review

We report a case of conversion paralysis after cervical spine arthroplasty performed in a 45-year-old woman to treat cervico-brachial neuralgia due to a left-sided C6–C7 disc herniation. Upon awakening from the anaesthesia, she had left hemiplegia sparing the face, with normal sensory function. Magnetic resonance imaging (MRI) of the brain ruled out a stroke. MRI of the spinal cord showed artefacts from the cobalt-chrome prosthesis that precluded confident elimination of mechanical spinal cord compression. Surgery performed on the same day to substitute a cage for the prosthesis ruled out spinal cord compression, while eliminating the source of MRI artefacts. Findings were normal from follow-up MRI scans 1 and 15days later, as well as from neurophysiological testing (electromyogram and motor evoked potentials). The deficit resolved fully within the next 4days. A psychological assessment revealed emotional distress related to an ongoing divorce. The most likely diagnosis was conversion paralysis. Surgeons should be aware that conversion disorder might develop after a procedure on the spine, although the risk of litigation requires re-operation. Familiarity with specific MRI sequences that minimise artefacts can be valuable. A preoperative psychological assessment might improve the detection of patients at high risk for conversion disorder.

La lésion fonctionnelle dans la conversion hystérique : des aliénistes à l’imagerie cérébrale

Recent progress in functional imagery confirmed the intuition of the 19th century French alienists who introduced, before Charcot, the concept of “functional lesion” applied to hysterical conversion. Neural mechanism underlying conversion paralysis has been more particularly studied in recent years using these new tools. Distinct patterns of brain activation have been elicited in healthy subjects simulating weakness and conversion paralysis. Several brain areas are over-activated in conversion paralysis when compared to healthy subjects: prefrontal cortex, precuneus, anterior cingulate cortex, amygdala. These results, not only confirm that conversion must be distinguished from malingering, they also provide new insights on the neural mechanisms of conversion paralysis. The activation of regions associated to the default mode network such as the precuneus and the ventral prefrontal cortex could reflect an increase in self-monitoring or motor imagery. The involvement of limbic regions like the anterior cingulate cortex and the amygdala suggest disturbed influence of emotional processes over motor execution. In the second part of this study, we report the results of brain structural and functional explorations performed in a case of chronic left conversion paralysis. The abnormal involvement of the precuneus is discussed together with the possible transition from functional to organic lesion in chronic paralysis. Simultaneous presence of sensory impairment and more remarkably left spatial neglect emphasize the singularity of each case and the necessary caution that should be taken for the interpretation of brain images. From a therapeutic point of view, these data could provide some new theoretical basis for rehabilitation and the use of brain stimulation techniques.

P 115. Effects of rTMS in conversion paralysis

Introduction Conversion paralysis (CP) concerns patients with unintentional neurological symptoms (i.e. paralysis) which are present without a neurological explanation. Neuroimaging research shows that abnormal cerebral activity accompanies conversion paralysis. Previously, a positive effect of repetitive transcranial magnetic stimulation (rTMS) in CP was reported (Schonfeldt-Lecuona et al., 2006) after 110% motor threshold (MT) stimulation. To avoid a psychological effect of thumb movement, we stimulated below MT (80%). Objective Does rTMS treatment decrease symptoms in conversion disorder? Methods 10 subjects (three male, 34–65years old) with CP of the hand were admitted to the hospital for two weeks, with the exception of weekends and received rTMS over the contralateral motor cortex (hand area) during 30min, 2 times 5days, once a day (15Hz, 300×2s trains, intensity 80% of motor threshold). Illness duration varied between 4weeks and 25years. 6 out of 10 patients were additionally included in a sham condition. Before the first session and after the last session, we monitored strength of the hand muscles using dynamometry and subjective patients' ratings. A Wilcoxon signed-rank test was used to compare muscle strength before and after rTMS. Preliminary results A Wilcoxon Signed Ranks Test showed a significant effect of rTMS ( Z =−2.803, p =0.005). Indeed, median muscle strength before rTMS was 36.5Newton, median muscle strength after rTMS was 64Newton. In contrast, only 2 patients showed improvement in the sham condition, 3 out of 6 patients showed no improvement after sham rTMS and 1 patient showed reduced muscle strength. The median muscle strength pre-and post-sham rTMS was 42.5 and 34.5Newton. The subjective patient's rating did not match these results, only 2 patients reported subjective improvement of the function of their hand after rTMS. Conclusion These results confirm that 80% rTMS is an effective method to increase muscle strength in patients with conversion paralysis. Its effect does not rely on psychological components such as visible thumb movement.

Response inhibition in motor conversion disorder

Conversion disorders (CDs) are unexplained neurological symptoms presumed to be related to a psychological issue. Studies focusing on conversion paralysis have suggested potential impairments in motor initiation or execution. Here we studied CD patients with aberrant or excessive motor movements and focused on motor response inhibition. We also assessed cognitive measures in multiple domains. We compared 30 CD patients and 30 age-, sex-, and education-matched healthy volunteers on a motor response inhibition task (go/no go), along with verbal motor response inhibition (color-word interference) and measures of attention, sustained attention, processing speed, language, memory, visuospatial processing, and executive function including planning and verbal fluency. CD patients had greater impairments in commission errors on the go/no go task (P < .001) compared with healthy volunteers, which remained significant after Bonferroni correction for multiple comparisons and after controlling for attention, sustained attention, depression, and anxiety. There were no significant differences in other cognitive measures. We highlight a specific deficit in motor response inhibition that may play a role in impaired inhibition of unwanted movement such as the excessive and aberrant movements seen in motor conversion. Patients with nonepileptic seizures, a different form of conversion disorder, are commonly reported to have lower IQ and multiple cognitive deficits. Our results point toward potential differences between conversion disorder subgroups. © 2013 Movement Disorder Society.

Deciphering the Neural Signature of Conversion Blindness

Deciphering the Neural Signature of Conversion Blindness

Aberrant supplementary motor complex and limbic activity during motor preparation in motor conversion disorder

Conversion disorder (CD) is characterized by unexplained neurological symptoms presumed related to psychological issues. The main hypotheses to explain conversion paralysis, characterized by a lack of movement, include impairments in either motor intention or disruption of motor execution, and further, that hyperactive self-monitoring, limbic processing or top-down regulation from higher order frontal regions may interfere with motor execution. We have recently shown that CD with positive abnormal or excessive motor symptoms was associated with greater amygdala activity to arousing stimuli along with greater functional connectivity between the amygdala and supplementary motor area. Here we studied patients with such symptoms focusing on motor initiation. Subjects performed either an internally or externally generated 2-button action selection task in a functional MRI study. Eleven CD patients without major depression and 11 age- and gender-matched normal volunteers were assessed. During both internally and externally generated movement, conversion disorder patients relative to normal volunteers had lower left supplementary motor area (SMA) (implicated in motor initiation) and higher right amygdala, left anterior insula, and bilateral posterior cingulate activity (implicated in assigning emotional salience). These findings were confirmed in a subgroup analysis of patients with tremor symptoms. During internally versus externally generated action in CD patients, the left SMA had lower functional connectivity with bilateral dorsolateral prefrontal cortices. We propose a theory in which previously mapped conversion motor representations may in an arousing context hijack the voluntary action selection system, which is both hypoactive and functionally disconnected from prefrontal top-down regulation.

Conversion Paralysis After Surgery for Lumbar Disc Herniation

New neurologic deficit after spinal surgery is a rare complication that must be promptly diagnosed and treated to reduce the risk of permanent neurologic disability. A 37-year-old woman underwent left laminotomy and L5-S1 diskectomy for the treatment of L5-S1 disc herniation. She was found to be normal after recovery from anesthesia but loss of muscle power in the left lower limb after 1 h. Surgical exploration was performed; no obvious hemorrhage or compression because of hematoma was observed. After the exploration, the muscle power recovered but deteriorated after 10 h. Re-exploration did not yield any specific findings. In view of the normal electrophysiological and anatomic findings, a psychiatric evaluation confirmed the diagnosis of conversion paralysis with major depression disorder. Normal somatosensory-evoked potentials or motor-evoked potentials in a patient denying sensation of stimuli offer objective evidence of the psychogenic nature of the para/tetraplegia. This report describes a case in which psychopathology interfered with the outcome of a frequently used procedure for a well-defined, chronic, painful condition.

Altered connectivity between prefrontal and sensorimotor cortex in conversion paralysis

Conversion paralysis (CP) is a frequent and impairing psychiatric disorder, affecting voluntary motor function. Yet, we have previously shown that the motor system of CP patients with a unilateral conversion paresis is recruited to a similar degree during imagined movements of the affected and unaffected limb. In contrast, imagery of movements with the affected limb results in larger prefrontal activation. It remains unclear how this hand-specific increased prefrontal activity relates to the reduced responsiveness of motor and somatosensory areas, a consistent and important feature of CP patients.In the current study, we investigated changes in the inter-regional coupling between prefrontal cortex (PFC) and sensorimotor regions when CP patients imagined movements involving either the affected or the unaffected hand. We found that there were distinct connectivity patterns for different parts of the PFC. While ventromedial PFC was not functionally connected to the motor system, we observed strong functional coupling between the dorsolateral PFC and various sensorimotor areas. Furthermore, this coupling was modulated by whether patients imagined movements of their affected or unaffected hand. Together, these results suggest that the reduced motor responsitivity observed in CP may be linked to altered dorsolateral prefrontal-motor connectivity.

Motor inhibition in hysterical conversion paralysis

Brain mechanisms underlying hysterical conversion symptoms are still poorly known. Recent hypotheses suggested that activation of motor pathways might be suppressed by inhibitory signals based on particular emotional situations. To assess motor and inhibitory brain circuits during conversion paralysis, we designed a go–nogo task while a patient underwent functional magnetic resonance imaging (fMRI). Preparatory activation arose in right motor cortex despite left paralysis, indicating preserved motor intentions, but with concomitant increases in vmPFC regions that normally mediate motivational and affective processing. Failure to execute movement on go trials with the affected left hand was associated with activations in precuneus and ventrolateral frontal gyrus. However, right frontal areas normally subserving inhibition were activated by nogo trials for the right (normal) hand, but not during go trials for the left hand (affected by conversion paralysis). By contrast, a group of healthy controls who were asked to feign paralysis showed similar activation on nogo trials and left-go trials with simulated weakness, suggesting that distinct inhibitory mechanisms are implicated in simulation and conversion paralysis. In the patient, right motor cortex also showed enhanced functional connectivity with the posterior cingulate cortex, precuneus, and vmPFC. These results suggest that conversion symptoms do not act through cognitive inhibitory circuits, but involve selective activations in midline brain regions associated with self-related representations and emotion regulation.

Video Neuro Image : Diagnosing conversion weakness with the Spinal Injuries Center test

The Hoover sign has been used since 1908 to aid in diagnosing conversion paralysis in unilateral lower extremity weakness. The abductor sign tests the …

Motor imagery: A window into the mechanisms and alterations of the motor system

Motor imagery is a widely used paradigm for the study of cognitive aspects of action control, both in the healthy and the pathological brain. In this paper we review how motor imagery research has advanced our knowledge of behavioral and neural aspects of action control, both in healthy subjects and clinical populations. Furthermore, we will illustrate how motor imagery can provide new insights in a poorly understood psychopathological condition: conversion paralysis (CP). We measured behavioral and cerebral responses with functional magnetic resonance imaging (fMRI) in seven CP patients with a lateralized paresis of the arm as they imagined moving the affected or the unaffected hand. Imagined actions were either implicitly induced by the task requirements, or explicitly instructed through verbal instructions. We previously showed that implicitly induced motor imagery of the affected limb leads to larger ventromedial prefrontal responses compared to motor imagery of the unaffected limb. We interpreted this effect in terms of greater self-monitoring of actions during motor imagery of the affected limb. Here, we report new data in support of this interpretation: inducing self-monitoring of actions of both the affected and the unaffected limb (by means of explicitly cued motor imagery) abolishes the activation difference between the affected and the unaffected hand in the ventromedial prefrontal cortex. Our results show that although implicit and explicit motor imagery both entail motor simulations, they differ in terms of the amount of action monitoring they induce. The increased self-monitoring evoked by explicit motor imagery can have profound cerebral consequences in a psychopathological condition.

Increased self-monitoring during imagined movements in conversion paralysis

Conversion paralysis is characterized by a loss of voluntary motor functioning without an organic cause. Despite its prevalence among neurological outpatients, little is known about the neurobiological basis of this motor dysfunction. We have examined whether the motor dysfunction in conversion paralysis can be linked to inhibition of the motor system, or rather to enhanced self-monitoring during motor behavior. We measured behavioral and cerebral responses (with fMRI) in eight conversion paralysis patients with a lateralized paresis of the arm as they were engaged in imagined actions of the affected and unaffected hand. We used a within-subjects design to compare cerebral activity during imagined movements of the affected and the unaffected hand. Motor imagery of the affected hand and the unaffected hand recruited comparable cerebral resources in the motor system, and generated equal behavioral performance. However, motor imagery of the affected limb recruited additional cerebral resources in the ventromedial prefrontal cortex and superior temporal cortex. These activation differences were caused by a failure to de-activate these regions during movement imagery of the affected hand. These findings lend support to the hypothesis that conversion paralysis is associated with heightened self-monitoring during actions with the affected arm.

Conversion Disorder

Conversion Disorder

Functional correlates of conversion and hypnotic paralysis: a neurophysiological hypothesis

AbstractSince conversion disorder was thoroughly described by Pierre Janet psychiatric findings have traditionally been the only available source of contribution to the clarification of the phenomena. Some recent cognitive approaches though, have tried to explain conversion paralysis in terms of a disconnection phenomenon supposedly causative of degeneration in motor information processes. These approaches though relevant are purely theoretical, and only in recent years has neurological research provided sufficient evidence to commence developing a neuropsychological theory of conversion paralysis. Defined cortical regions like the anterior cingulate cortex (ACC) and orbitofrontal cortex (OFC) have been found to be related to conversion and hypnotic paralysis, while on the other hand, psychological evidence linking hypnotizability and conversion has also emerged. This paper attempts to relate some neurological and psychological evidence in a first step towards a general theory of conversion paralysis. Copyright © 2005 British Society of Experimental &amp; Clinical Hypnosis. Published by John Wiley &amp; Sons, Ltd.

Abnormal brain activation during movement observation in patients with conversion paralysis

Dissociative paralysis in conversion disorders has variably been attributed to a lack of movement initiation or an inhibition of movement. While psychodynamic theory suggests altered movement conceptualization, brain activation associated with observation and replication of movements has so far not been assessed neurobiologically. Here, we measured brain activation by functional magnetic resonance imaging during observation and subsequent imitative execution of movements in four patients with dissociative hand paralysis. Compared to healthy controls conversion disorder patients showed decreased activation of cortical hand areas during movement observation. This effect was specific to the side of their dissociative paralysis. No brain activation compatible with movement inhibition was observed. These findings indicate that in dissociative paralysis, there is not only derangement of movement initiation but already of movement conceptualization. This raises the possibility that strategies targeted at reestablishing appropriate movement conceptualization may contribute to the therapy of dissociative paralysis.

Hyperactive action monitoring during motor-initiation in conversion paralysis: An event-related potential study

Conversion paralysis (CP) is featured by a stress-induced tonic immobility. Although the neural correlates of this psychiatric condition remain largely unexplored, previous reports showed CP to be associated with anterior cingulate cortex (ACC) hyperactivity. We examined the ACC action monitoring function by recording event-related potentials (ERPs) when conversion patients ( n = 6) with unilateral arm paresis made speeded responses with their affected and healthy arms on a flankers task. During this task, pre-response ACC action monitoring is reflected in the N2 ERP component, which is increased when incongruent stimuli lead to simultaneously activated competing response tendencies. The results showed that the N2 congruency effects were significantly increased for responses with affected hands compared to healthy hands. There were no such results for post-response monitoring. This study is the first to present electrophysiological correlates of action monitoring in CP and suggests ACC to be hyperactive when movements with affected arms are to be initiated.

Endogenous and Exogenous Attention in Patients with Conversion Paresis

Endogenous and exogenous attention of patients with conversion paresis was investigated using Posner's ‘covert orienting of visual attention’ task. In the light of previous evidence showing that inhibition of higher‐level control functions plays a role in conversion paralysis (e.g., Marshall, Halligan, Fink, Wade, & Frackowiak, 1997), patients were expected to display weaker cue effects in the endogenous condition and weaker inhibition of return (IOR) in the exogenous condition. Eight patients with conversion paresis in one or more limbs and eight healthy controls were administered the attention task in a verbal response condition and in a limb response condition in which subjects responded with each limb separately. When responding verbally, patients showed relatively weakened endogenous cue effects on a 150‐ms stimulus onset asynchronicity (SOA) and no IOR in the exogenous condition. Comparable effects emerged when patients responded with affected limbs but not when they responded with unaffected limbs. The findings suggest impairment in voluntary attention. High‐level inhibition is suggested to interfere with the orientation to stimuli that prime responses with affected limbs. The fact that similar results were found for verbal responses is interpreted as supporting the view that attention deficits are manifested on a high, abstract level of cognitive processing.

Selective attention as possible mechanism of symptom production in conversion disorders

Brain mechanisms underlying hysterical conversion symptoms are still poorly known. Recent hypotheses suggested that activation of motor pathways might be suppressed by inhibitory signals based on particular emotional situations. To assess motor and inhibitory brain circuits during conversion paralysis, we designed a go–nogo task while a patient underwent functional magnetic resonance imaging (fMRI). Preparatory activation arose in right motor cortex despite left paralysis, indicating preserved motor intentions, but with concomitant increases in vmPFC regions that normally mediate motivational and affective processing. Failure to execute movement on go trials with the affected left hand was associated with activations in precuneus and ventrolateral frontal gyrus. However, right frontal areas normally subserving inhibition were activated by nogo trials for the right (normal) hand, but not during go trials for the left hand (affected by conversion paralysis). By contrast, a group of healthy controls who were asked to feign paralysis showed similar activation on nogo trials and left-go trials with simulated weakness, suggesting that distinct inhibitory mechanisms are implicated in simulation and conversion paralysis. In the patient, right motor cortex also showed enhanced functional connectivity with the posterior cingulate cortex, precuneus, and vmPFC. These results suggest that conversion symptoms do not act through cognitive inhibitory circuits, but involve selective activations in midline brain regions associated with self-related representations and emotion regulation.

Motor initiation and execution in patients with conversion paralysis

Motor initiation and motor execution in four patients with conversion paralysis were investigated in a non-affected motor modality (speech). In line with the hypothesis of dissociated control in conversion disorder [Cognit. Neuropsychiatry 8 (1) (2001) 21] motor initiation, but not response duration, was expected to be impaired. The motor initiation times (reaction time: RT) and motor execution times (response duration: RD) were compared on four RT-tasks that required the production of a verbal response: a simple choice RT-task, a mental letter rotation task, and an implicit and an explicit mental hand rotation task. Because conversion disorder is expected to primarily involve an impairment in the initiation of movement, we expected the following task characteristics to uniquely affect RT and not RD: type of instruction (implicit versus explicit instructed imagery), angle of rotation, and target arm (affected versus non-affected arm). The results indeed showed the task characteristics to significantly affect the participants' RT and not their RD. It was concluded that conversion paralysis is associated with a specific impairment in the explicit initiation of processes with a spatial and motor component.