Selma Aybek

The value of ‘positive’ clinical signs for weakness, sensory and gait disorders in conversion disorder: a systematic and narrative review

Experts in the field of conversion disorder have suggested for the upcoming DSM-V edition to put less weight on the associated psychological factors and to emphasise the role of clinical findings. Indeed, a critical step in reaching a diagnosis of conversion disorder is careful bedside neurological examination, aimed at excluding organic signs and identifying ‘positive’ signs suggestive of a functional disorder. These positive signs are well known to all trained neurologists but their validity is still not established. The aim of this study is to provide current evidence regarding their sensitivity and specificity. We conducted a systematic search on motor, sensory and gait functional signs in Embase, Medline, PsycINfo from 1965 to June 2012. Studies in English, German or French reporting objective data on more than 10 participants in a controlled design were included in a systematic review. Other relevant signs are discussed in a narrative review. Eleven controlled studies (out of 147 eligible articles) describing 14 signs (7 motor, 5 sensory, 2 gait) reported low sensitivity of 8–100% but high specificity of 92–100%. Studies were evidence class III, only two had a blinded design and none reported on inter-rater reliability of the signs. Clinical signs for functional neurological symptoms are numerous but only 14 have been validated; overall they have low sensitivity but high specificity and their use should thus be recommended, especially with the introduction of the new DSM-V criteria.

Rapid resolution of dopamine dysregulation syndrome (DDS) after subthalamic DBS for Parkinson disease (PD): a case report.

ObjectiveTo describe how subthalamic deep brain stimulation (STN-DBS) and reduction in dopamine replacement therapy (DRT) allowed rapid resolution of dopamine dysregulation syndrome (DDS) with severe behavioral disorder in a patient with late stage Parkinson disease (PD). BackgroundDDS was recently defined as compulsive use of dopaminergic drugs, associated with severe behavioral symptoms, and impaired social functioning, occurring in about 4% of PD patients under DRT. STN-DBS is an effective treatment for late stage PD with treatment resistant motor fluctuations, which frequently allows also to reduce DRT. MethodsA late stage PD patient referred to our center for STN-DBS, suffering from severe DDS necessitating in-ward psychiatric management, was comprehensively assessed preoperatively and postoperatively for motor, cognitive, and psychiatric status. ResultsFollowing subthalamic DBS procedure and medication reduction, we observed a rapid and dramatic resolution of DDS and associated psychiatric symptoms, allowing discharge from a 2-year stay in a psychiatric institution. ConclusionsDDS occurring in late stage PD patients may be dramatically improved by STN-DBS, possibly in relation with the reduction of dopaminergic medication. In contrast to other psychiatric symptoms, DDS should not be considered as an obstacle to DBS procedure in late stage PD patients.

The neuropsychiatry of conversion disorder.

Purpose of review During the past two decades there has been a relative surge of interest in conversion disorder, and a multitude of studies have emerged on the subject. With continuing developments in neuroscience – mainly brain imaging – new applications to conversion disorder are being reported every year. Recent findings Diagnosis continues to represent a challenge, although neurological signs are increasingly being developed and validated to assist with this. Psychiatric co-morbidity diagnosed according to operational criteria is common. Brain imaging studies have brought some clues to understanding the pathophysiology of conversion disorder. Summary Evidence-based medicine requires reliable diagnostic criteria, and attempts have recently been made to validate some of the well known neurological signs of conversion disorder. From a psychiatric point of view, there is a need for greater understanding of the aetiology and mechanisms underlying conversion disorder and its relationship to other psychiatric disorders. Although advances have been made both in diagnostic methods and in the groundwork for a neurobiological model, no clear rationale for treatment is yet available and further research is strongly needed.

Emotion-motion interactions in conversion disorder: an FMRI study

Objectives To evaluate the neural correlates of implicit processing of negative emotions in motor conversion disorder (CD) patients. Methods An event related fMRI task was completed by 12 motor CD patients and 14 matched healthy controls using standardised stimuli of faces with fearful and sad emotional expressions in comparison to faces with neutral expressions. Temporal changes in the sensitivity to stimuli were also modelled and tested in the two groups. Results We found increased amygdala activation to negative emotions in CD compared to healthy controls in region of interest analyses, which persisted over time consistent with previous findings using emotional paradigms. Furthermore during whole brain analyses we found significantly increased activation in CD patients in areas involved in the ‘freeze response’ to fear (periaqueductal grey matter), and areas involved in self-awareness and motor control (cingulate gyrus and supplementary motor area). Conclusions In contrast to healthy controls, CD patients exhibited increased response amplitude to fearful stimuli over time, suggesting abnormal emotional regulation (failure of habituation / sensitization). Patients with CD also activated midbrain and frontal structures that could reflect an abnormal behavioral-motor response to negative including threatening stimuli. This suggests a mechanism linking emotions to motor dysfunction in CD.

What's so special about conversion disorder? A problem and a proposal for diagnostic classification.

Conversion disorder presents a problem for the revisions of DSM-IV and ICD-10, for reasons that are informative about the difficulties of psychiatric classification more generally. Giving up criteria based on psychological aetiology may be a painful sacrifice but it is still the right thing to do.

Grey matter changes in motor conversion disorder

Objective To detect anatomical differences in areas related to motor processing between patients with motor conversion disorder (CD) and controls. Methods T1-weighted 3T brain MRI data of 15 patients suffering from motor CD (nine with hemiparesis and six with paraparesis) and 25 age- and gender-matched healthy volunteers were compared using voxel-based morphometry (VBM) and voxel-based cortical thickness (VBCT) analysis. Results We report significant cortical thickness (VBCT) increases in the bilateral premotor cortex of hemiparetic patients relative to controls and a trend towards increased grey matter volume (VBM) in the same region. Regression analyses showed a non-significant positive correlation between cortical thickness changes and symptom severity as well as illness duration in CD patients. Conclusions Cortical thickness increases in premotor cortical areas of patients with hemiparetic CD provide evidence for altered brain structure in a condition with presumed normal brain anatomy. These may either represent premorbid vulnerability or a plasticity phenomenon related to the disease with the trends towards correlations with clinical variables supporting the latter.

Interobserver agreement and validity of bedside ‘positive signs’ for functional weakness, sensory and gait disorders in conversion disorder: a pilot study

Background Conversion disorder (CD) is no longer a diagnosis of exclusion. The new DSM-V criteria highlight the importance of ‘positive signs’ on neurological examination. Only few signs have been validated, and little is known about their reliability. Objective The aim was to examine the clinical value of bedside positive signs in the diagnosis of CD presenting with weakness, gait or sensory symptoms by assessing their specificity, sensitivity and their inter-rater reliability. Patients and methods Standardised video recorded neurological examinations were performed in 20 consecutive patients with CD and 20 ‘organic’ controls. Ten previously validated sensory and motor signs were grouped in a scale. Thirteen additional motor/sensory ‘positive signs’, 14 gait patterns and 1 general sign were assessed in a pilot validation study. In addition, two blinded independent neurologists rated the video recordings to assess the inter-rater reliability (Cohens κ) of each sign. Results A score of ≥4/14 on the sensory motor scale showed a 100% specificity (CI 85 to 100) and a 95% sensitivity (CI 85 to 100). Among the additional tested signs, 10 were significantly more frequent in CD than controls. The interobserver agreement was acceptable for 23/38 signs (2 excellent, 10 good, 11 moderate). Conclusions Our study confirms that six bedside ‘positive signs’ are highly specific for CD with good-excellent inter-rater reliability; we propose to consider them as ‘highly reliable signs’. In addition 13 signs could be considered as ‘reliable signs’ and six further signs as ‘suggestive signs’ while all others should be used with caution until further validation is available.

A structural MRI study of motor conversion disorder: evidence of reduction in thalamic volume

Objective To investigate potential abnormalities in subcortical brain structures in conversion disorder (CD) compared with controls using a region of interest (ROI) approach. Methods Fourteen patients with motor CD were compared with 31 healthy controls using high-resolution MRI scans with an ROI approach focusing on the basal ganglia, thalamus and amygdala. Brain volumes were measured using Freesurfer, a validated segmentation algorithm. Results Significantly smaller left thalamic volumes were found in patients compared with controls when corrected for intracranial volume. These reductions did not vary with handedness, laterality, duration or severity of symptoms. Conclusions These differences may reflect a primary disease process in this area or be secondary effects of the disorder, for example, resulting from limb disuse. Larger, longitudinal structural imaging studies will be required to confirm the findings and explore whether they are primary or secondary to CD.

Life events and escape in conversion disorder

Background Psychological models of conversion disorder (CD) traditionally assume that psychosocial stressors are identifiable around symptom onset. In the face of limited supportive evidence such models are being challenged. Method Forty-three motor CD patients, 28 depression patients and 28 healthy controls were assessed using the Life Events and Difficulties Schedule in the year before symptom onset. A novel ‘escape’ rating for events was developed to test the Freudian theory that physical symptoms of CD could provide escape from stressors, a form of ‘secondary gain’. Results CD patients had significantly more severe life events and ‘escape’ events than controls. In the month before symptom onset at least one severe event was identified in 56% of CD patients – significantly more than 21% of depression patients [odds ratio (OR) 4.63, 95% confidence interval (CI) 1.56–13.70] and healthy controls (OR 5.81, 95% CI 1.86–18.2). In the same time period 53% of CD patients had at least one ‘high escape’ event – again significantly higher than 14% in depression patients (OR 6.90, 95% CI 2.05–23.6) and 0% in healthy controls. Previous sexual abuse was more commonly reported in CD than controls, and in one third of female patients was contextually relevant to life events at symptom onset. The majority (88%) of life events of potential aetiological relevance were not identified by routine clinical assessments. Nine per cent of CD patients had no identifiable severe life events. Conclusions Evidence was found supporting the psychological model of CD, the Freudian notion of escape and the potential aetiological relevance of childhood traumas in some patients. Uncovering stressors of potential aetiological relevance requires thorough psychosocial evaluation.

Stressful life events and maltreatment in conversion (functional neurological) disorder: systematic review and meta-analysis of case-control studies

BACKGROUND Stressful life events and maltreatment have traditionally been considered crucial in the development of conversion (functional neurological) disorder, but the evidence underpinning this association is not clear. We aimed to assess the association between stressors and functional neurological disorder. METHODS We systematically reviewed controlled studies reporting stressors occurring in childhood or adulthood, such as stressful life events and maltreatment (including sexual, physical abuse, and emotional neglect) and functional neurological disorder. We did a meta-analysis, with assessments of methodology, sources of bias, and sensitivity analyses. FINDINGS 34 case-control studies, with 1405 patients, were eligible. Studies were of moderate-to-low quality. The frequency of childhood and adulthood stressors was increased in cases compared with controls. Odds ratios (OR) were higher for emotional neglect in childhood (49% for cases vs 20% for controls; OR 5·6, 95% CI 2·4-13·1) compared with sexual abuse (24% vs 10%; 3·3, 2·2-4·8) or physical abuse (30% vs 12%; 3·9, 2·2-7·2). An association with stressful life events preceding onset (OR 2·8, 95% CI 1·4-6·0) was stronger in studies with better methods (interviews; 4·3, 1·4-13·2). Heterogeneity was significant between studies (I2 21·1-90·7%). 13 studies that specifically ascertained that the participants had not had either severe life events or any subtype of maltreatment all found a proportion of patients with functional neurological disorder reporting no stressor. INTERPRETATION Stressful life events and maltreatment are substantially more common in people with functional neurological disorder than in healthy controls and patient controls. Emotional neglect had a higher risk than traditionally emphasised sexual and physical abuse, but many cases report no stressors. This outcome supports changes to diagnostic criteria in DSM-5; stressors, although relevant to the cause in many patients, are not a core diagnostic feature. This result has implications for ICD-11. FUNDING None.