Downloaded from jnnp.bmj.com on March 7, 2013 - Published by group.bmj.com JNNP Online First, published on March 6, 2013 as 10.1136/jnnp-2012-304607 Neuropsychiatry REVIEW The value of ‘positive’ clinical signs for weakness, sensory and gait disorders in conversion disorder: a systematic and narrative review Corinna Daum,1 Monica Hubschmid,2 Selma Aybek1 ▸ Additional material is ABSTRACT findings play a crucial role. Indeed, the DSM-V task published online only. To view fi fi Experts in the eld of conversion disorder have forceproposedtointroduceanewcriterionstating this le please visit the journal ‘ fi online (http://dx.doi.org/ suggested for the upcoming DSM-V edition to put less that: clinical ndings provide evidence of internal 10.1136/jnnp-2012-304607) weight on the associated psychological factors and to inconsistency or incompatibility with recognised emphasise the role of clinical findings. Indeed, a critical neurological or medical disease’. This distinction is 1Department of Neurology, Clinical Neurosciences step in reaching a diagnosis of conversion disorder is based on the exclusion of neurological signs pointing Department, University Hospital careful bedside neurological examination, aimed at to a lesion of the central or peripheral nervous (CHUV), Lausanne, Switzerland excluding organic signs and identifying ‘positive’ signs system, together with the identification of ‘positive 2 Psychiatric Liaison Service, suggestive of a functional disorder. These positive signs signs’ knowntobespecific for functional symptoms.7 Psychiatry Department, University Hospital (CHUV), are well known to all trained neurologists but their In the era of evidence-based medicine however, Lausanne, Switzerland validity is still not established. The aim of this study is to clinicians are facing a lack of proof regarding the val- provide current evidence regarding their sensitivity and idity of those clinical ‘positive signs’. The majority of Correspondence to specificity. We conducted a systematic search on motor, the commonly used signs rely on traditional knowl- Dr Selma Aybek, Department sensory and gait functional signs in Embase, Medline, edge and very few have been validated.8 Diagnostic of Neurology, Clinical 9 Neurosciences Department, PsycINfo from 1965 to June 2012. Studies in English, criteria for movement disorders exist, reliable signs 10 University Hospital (CHUV), German or French reporting objective data on more than for non-epileptic seizures are available and both Service de Neurologie- BH13, 10 participants in a controlled design were included in a presentations have laboratory supportive criteria11 12 Bugnon 44, Lausanne 1011, systematic review. Other relevant signs are discussed in a to help with diagnosis. Therefore we chose to focus Switzerland; [email protected] narrative review. Eleven controlled studies (out of 147 here on clinical signs pertaining to weakness, sensory eligible articles) describing 14 signs (7 motor, 5 sensory, and gait disorders. The aim of this study is to Received 17 November 2012 2 gait) reported low sensitivity of 8–100% but high provide a systematic review of the existing validated Revised 23 January 2013 specificity of 92–100%. Studies were evidence class III, clinical ‘positive signs’ and report their specificity Accepted 5 February 2013 only two had a blinded design and none reported on and sensitivity. In a narrative review we also critically inter-rater reliability of the signs. Clinical signs for discuss other described signs that have not been eval- functional neurological symptoms are numerous but only uated on objective criteria. 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 METHODS new DSM-V criteria. Search strategy The following databases were searched: Medline (from 1966), EMBASE (from 1980) and PsycINFO Conversion disorder (CD) is a disabling medical (from 1965) all to June 2012. Our search terms condition where patients present with a neuro- were: HYSTERIA, CONVERSION DISORDER, logical symptom for which no medical explanation DISSOCIATIVE DISORDER, FUNCTIONAL is found and which is interpreted as being rooted DISORDER, NON-ORGANIC, PSYCHOGENIC, in a psychological origin.12The term ‘conversion’ MEDICALLY UNEXPLAINED SYMPTOMS. They derives from Freud’s hypothesis of the conversion were combined with PARESIS, PARALYSIS, of a painful affect into a physical symptom, as a MOTOR SYMPTOM, MOTOR DEFICIT, defence mechanism to unbearable emotional stres- HEMIPARESIS, HEMIPLEGIA, PARAPARESIS, sors.3 Hence in the current Diagnostic and PARAPLEGIA, WEAKNESS, SENSORY Statistical Manual of Mental Disorders (DSM-IV) SYMPTOM, SENSORY DEFICIT, SENSORY manual; the association of a functional, medically LOSS, SENSITIVE, DERMATOMAL, GAIT, unexplained, neurological symptom (criterion A) WALK, CLINICAL SIGN, PHYSICAL with a psychological stressor (criterion B). There EXAMINATION, NEUROLOGICAL – has been a recent debate4 6 about which diagnostic EXAMINATION, NEUROLOGICAL SIGN. criteria should be retained in the future revised Excluded were SEIZURES and EPILEPSY. Abstracts DSM-V, most of the controversy being about the containing our search terms were sorted in a first To cite: Daum C, Hubschmid M, Aybek S. J role of psychological stressors and the differenti- screening and full-text articles were obtained using Neurol Neurosurg Psychiatry ation with malingering (criteria D) arguing that the defined inclusion criteria as far as possible (see Published Online First: both should disappear (DSM-V draft, http://www. below). The full-text articles were then selected in [please include Day Month dsm5.org). Thus, the adequate evaluation of the a second-stage screening using the inclusion cri- Year] doi:10.1136/jnnp- 2012-304607 presenting neurological symptom and clinical teria. Both steps were accomplished by two authors DaumCopyright C, et al. J Neurol Article Neurosurg author Psychiatry (or2013; their0:1– 11.employer) doi:10.1136/jnnp-2012-304607 2013. Produced by BMJ Publishing Group Ltd under licence. 1 Downloaded from jnnp.bmj.com on March 7, 2013 - Published by group.bmj.com Neuropsychiatry (CD/SA). The bibliographies of all articles were looked at and focused on objective equivalents of clinical signs: Hoover19 hand searching of pertinent journals was undertaken. An add- and give-way weakness.19 20 Three studies compared clinical itional hand search for every single cited ‘positive sign’ was characteristics of functional and organic patients in case-control – undertaken. designs.21 23 Two studies using objective quantification methods were judged Class II and nine studies using clinical bedside tests Eligibility criteria were judged class III, none reported inter-rater reliability of the Studies were included if they met the following criteria: signs. Altogether, those studies reported information on 14 clinical ▸ Studying clinical signs on neurological examination signs (7 motor, 5 sensory, 2 gait), most of them in single studies, in patients with hysteria/conversion disorder/dissociative with the exception of the Hoover sign (4 studies). A detailed disorder/functional disorder/non-organic disorder/ description of those signs is presented here (see also table 1). psychogenic disorder or medically unexplained symptoms presenting a motor or sensory deficit or gait disorder. Motor signs ▸ Reports written in English, French or German. The Hoover’s sign is based on the assumption that when a limb ▸ The participants were over 18 years. does a flexion, the contralateral limb does a reflex simultaneous ▸ There were more than 10 participants in the study. extension movement. It is considered positive when there is ▸ A control group was available. weakness of voluntary hip extension in the presence of normal ▸ An evaluation of sensitivity and specificity of a ‘positive involuntary hip extension during contralateral hip flexion against sign’ was available. resistance. Our systematic search identified four studies reporting ▸ Minimum class III evidence level according to the classifi- the frequency of this sign. The sensitivity varied between cation scheme employed by the American Academy of 100%,15 95%,21 75%14 and 63%13 and specificity between – Neurology. 100%13 15 and 86%.21 The first three studies were not primarily Studies focused on factitious disorder, malingering or chronic designed to evaluate the Hoover’s sign; only a subset of subjects pain were not considered, as well as studies focused on evoked (59% of patients and 16% of controls in21) presented leg weak- potentials, transcranial magnetic stimulation (TMS) or func- ness sufficient to render the Hoover’s sign applicable. Only the tional magnetic resonance (fMRI). Studies evaluating movement study of McWhirter et al was designed to prospectively evaluate disorders (tremor, dystonia, parkinsonism, etc), vertigo, deaf- this sign. Pooling the data of those four studies when Hoover’s ness, blindness or other functional symptoms or signs were sign was evaluable (148 controls and 92 patients) the overall esti- excluded. mated sensitivity is 94% and the specificity 99%. To obtain an objective equivalent of this test, a computerised Data extraction and analysis quantitative version of the manoeuvre has been evaluated19 in All reports were reviewed independently by two authors nine functional and seven organic patients. It showed a signifi- (CD/SA) and differences were reconciled by mutual agreement. cant increase in the involuntary/voluntary strength ratio