Psychogenic Movement Disorders Amitabh Gupta and Anthony E
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Psychogenic movement disorders Amitabh Gupta and Anthony E. Lang Movement Disorders Unit, Toronto Western Hospital, Purpose of review University of Toronto, Ontario, Canada This review summarizes the progress made in the area of psychogenic movement Correspondence to Dr Anthony E. Lang, MD, FRCPC, disorders (PMDs) over the past 2 years, and a simplified classification of diagnostic Director, Movement Disorders Unit, Toronto Western Hospital, 399 Bathurst Street, McLaughlin 7-418, certainty is proposed that incorporates electrophysiological assessment. Toronto M5T 2S8, Ontario, Canada Recent findings Tel: +1 416 603 6422; fax: +1 416 603 5004; e-mail: [email protected] Functional magnetic resonance imaging studies have demonstrated altered blood flow in conversion disorders that may reflect changes in synaptic activity. Current Opinion in Neurology 2009, 22:430–436 Electrophysiological testing shows limitations in distinguishing between psychogenic and organic propriospinal myoclonus and dystonia. Recent evidence cautions against the uncritical acceptance of all cases of posttraumatic myoclonus and ‘jumpy stump’ as being organic in nature. ‘Essential palatal tremor’ is recognized as a rather heterogeneous group of tremors that includes psychogenic tremor. Two recent studies evaluating the long-term prognosis of psychogenic tremor differ in the degree of unfavorable outcome. Different groups of PMDs might have distinctive gait characteristics with prognostic, diagnostic, or therapeutic value. Two recent reviews provide comprehensive information on the understudied area of PMDs in children. Summary The diagnosis of PMDs should not be regarded as a diagnosis of exclusion. Careful clinical assessment is critical, and imaging or electrophysiological studies may provide important insights and confirmation of the diagnosis though some cases remain challenging and current assessments fail to provide needed clarification. Treatment is often delayed, contributing to a largely unfavorable long-term outcome. Well designed randomized control trials that validate and compare therapeutic options are urgently required. Keywords children, diagnosis, investigations, movement disorders, psychogenic, treatment Curr Opin Neurol 22:430–436 ß 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 1350-7540 the literature of the past 2 years and summarize how Introduction PMDs are currently diagnosed, investigated, and treated. Psychogenic movement disorders (PMDs) are movement disorders that result from a psychological or psychiatric rather than neurological disturbance. The primary psy- Diagnosis chiatric diagnosis varies; most cases are considered to be Although no single clinical finding is pathognomonic for conversion disorders, in which the problem is caused by PMDs, several features are quite helpful. The clinical an unconscious mechanism, but infrequently some are aspects of specific types of PMDs (i.e. tremors, myoclo- factitious disorders or malingering, in which the abnormal nus, dystonia, Parkinsonism, gait disorders) have been movements are purposefully feigned. Traditionally, reviewed at length elsewhere [6–8]. Table 1 [8,9] pro- PMDs represented a diagnosis of exclusion. This percep- vides a list of typical historical and clinical clues to the tion was fuelled by the observation that PMDs can mimic diagnosis. various organic diseases, sometimes with confounding test results [1], and by studies and experiences of high Over a decade ago, criteria were proposed for various false positive rates [2–4]. Over the years, stricter clinical levels of diagnostic certainty of PMDs [10]. With the criteria, improved imaging, and investigational advances subsequent progress made in establishing clinical charac- have allowed the diagnosis of PMDs to be made more teristics and investigational methods, it appears timely comfortably [5], and organic movements are far less to propose modifications to the diagnostic classifica- often misdiagnosed as psychogenic. Here, we review tion, including the incorporation of electrophysiological 1350-7540 ß 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins DOI:10.1097/WCO.0b013e32832dc169 Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Psychogenic movement disorders Gupta and Lang 431 Table 1 Clues suggesting psychogenic cause Historical General examination Abrupt onset (symptoms often maximal at that time) Movement inconsistent Static course Variability over time (frequency, amplitude, direction/distribution of movement) Spontaneous remissions/cures Distractibility reduces or resolvesa, attention increases movement Paroxysmal symptoms (generally nonkinesigenic)b Selective disability Psychiatric comorbiditiesc Entrainment (especially with tremor) Secondary gain (often not apparent) Movement incongruous with organic movement disorders Risk factors for conversion disorderd Mixed (often bizarre) movement disorders Psychological stressorse Paroxysmal attacks (including pseudoseizures) Multiple somatizations/undiagnosed conditions Precipitated paroxysms (often suggestible/startle) Employed in allied health professions (infrequent) Suggestibilityf Effortful production or deliberate slowness (without fatiguing) of movement Self-inflicted injury (caution: tic disorders) Delayed and excessive startle response to a stimulus Burst of verbal gibberish or stuttering speechg False (give-away) weakness Nonanatomical sensory loss or spread of movement Certain types of abnormal movements common in individuals with PMDsh Functional disability out of proportion to examination findings a Distractibility should be tested both with mental and motor tasks. Although most often organic movement disorders are not suppressed, organic tics or akathisia can be suppressible, and recently it was shown that diaphragmatic tremor was suppressed by simple motor tasks, perhaps by interference with central nervous system circuitry [9]. b Separation from organic paroxysmal dyskinesias can be challenging, particularly if they occur infrequently with prolonged symptom-free periods. c Psychiatric diseases can also coincide with organic illness or present as part of the organic movement disorder. d Sexual and physical abuse, trauma. e Often initiated by injury (often minor) or motor vehicle accident associated with litigation or compensation. f Application of pressure with finger or tuning fork may reduce symptom. With paroxysmal symptom, suggestibility and placebo trial may not be helpful, unless repeated reversals with placebo are documented when symptom otherwise is frequent and attacks are prolonged. g Particularly if the entire word is repeated (typically broken up into syllables, each repeated), rather than the initial syllable. h Such movements include dystonia that begins as a fixed posture (particularly if abrupt onset, painful, and early contractures are seen); bizarre gait; twisting facial movements that move mouth to one side or the other (organic dystonia of the facial muscles usually does not pull the mouth sidewise). Adapted from [8]. techniques (Table 2) [10–12]. The remainder of this Patients with motor conversion disorders (MCDs) have review will discuss recent diagnostic and therapeutic been shown to activate the motor cortex in a pattern that approaches, with an emphasis on developments in the differs from controls simulating weakness [17]. areas of investigational methods, posttraumatic move- Although this suggests that cerebral activity is changed ment disorders, psychogenic tremor, psychogenic gait in MCD, comparison to organic weakness requires elu- disorders, and PMDs in children. cidation. Similarly, in patients with a sensory conversion disorder, fMRI has demonstrated that vibratory stimu- Investigations lation of the affected limb fails to activate the contra- Nuclear imaging, in contrast to magnetic resonance ima- lateral cortical sensory area. This result supports the ging (MRI), has proven quite helpful in distinguishing notion that clinical deficits in this psychiatric condition psychogenic Parkinsonism from Parkinson’s disease. are associated with real changes in blood flow that Well established methods include fluorodopa positron indicate reduced cortical responsiveness. The mechan- emission tomography (FDOPA-PET), bCIT single ism underlying these changes is not well understood, but photon emission computed tomography (SPECT) cortical activation was shown to be restored with bilateral [13,14], and, recently also, 123I-Isoflupane SPECT stimulation [18], possibly acting as a ‘distractor’ to [15]. As these methods detect the degree of viable reverse inhibition. dopaminergic neurons of the substantia nigra (PET) or their respective synaptic termini in the striatum Previous studies have established the utility of specialized (SPECT), scan results are normal in psychogenic cases electrophysiological techniques in aiding or confirming the but show diminished signal in Parkinson’s disease. diagnosis of certain PMDs, particularly psychogenic tre- Although it has been suggested that nuclear imaging mor and psychogenic myoclonus. These studies have been may be normal in some early cases of Parkinson’s disease, reviewed elsewhere [11,19,20]. Recent electrophysiologi- recent evidence suggests that most of these cases are cal studies have better delineated PMDs. Compared with likely falsely classified [16]. Therefore, nuclear imaging controls, PMD patients exhibited an excessive affective may be extremely useful in distinguishing psychogenic response to the startle eye blink reflex