Psychogenic Movement Disorders

Key points

Nomenclature and diagnostic criteria

This review uses the term, psychogenic movement disorder (PMD), acknowledging that there is considerable debate about the appropriate nomenclature. Several other terms have been used in the literature, including hysteria, functional, nonorganic, medically unexplained, and conversion disorder (Box 1).1, 2 The authors prefer the term psychogenic to functional because the latter term seems vague and patients perceive themselves as dysfunctional rather than functional. When the term psychogenic is

Prevalence and risk factors

The reported prevalence of PMDs at movement disorders clinic varies from 2% to 20%.⁹ These disorders are associated with marked disability and distress, reported to be similar to or greater than those reported by patients with neurodegenerative disease, such as Parkinson disease.¹⁰ A study evaluating the social impact of disease in patients with psychogenic neurologic disorders found these patients to have worse physical and mental health status compared with controls.¹¹ They were also more

Clinical features

The clinical history and neurologic examination provide the essential information needed to arrive at a clinical diagnosis. It is important to inquire about the circumstances regarding the onset of symptoms, the progression of symptoms, and variation over time. Additional history about other unexplained medical conditions, investigations, and procedures as well as social and family history can provide important contextual information regarding a patient’s clinical and social environment.

Historical features

PMDs typically have an abrupt onset with a rapid progression to maximum severity. Patients often recall the exact moment symptoms started and what they were doing at the time. The movements may be paroxysmal or episodic with spontaneous remissions and recurrences.²¹ Patients may describe a change in phenomenology over time. In addition to their motor symptoms, many have marked somatization and present a long list of other unexplained medical symptoms, such as atypical chest pain, fibromyalgia,

General clinical findings

Many features of PMDs can be noted through careful observation throughout the encounter in addition to focused examination (Box 4). The neurologic examination of PMDs often demonstrates variability of phenomenology in terms of direction, amplitude, and frequency. There can be distractibility of movements when focusing on other motor or mental tasks. Distractibility can be demonstrated by asking the patient to focus on motor tasks, such as finger tapping with the opposite hand, or more complex

Psychogenic tremor

Psychogenic tremor comprises the largest subcategory of PMDs, reported to represent approximately 50% of cases.²⁵ Psychogenic tremor is often present in all states (rest, posture, and kinetic), which is not typical of organic tremor. Tremor may spread to different body parts, especially when 1 limb is restrained or occupied with another activity. There are several classic clinical features of psychogenic tremor that can be demonstrated in the clinic or at the bedside (Video 2).²⁶ Tremor

Psychogenic dystonia

Psychogenic dystonia may present as fixed or mobile dystonia. Patient with psychogenic dystonia generally do not describe alleviating maneuvers or sensory tricks that are typically used by patients with organic dystonia to correct the abnormal posture.³⁴ Although the posture is fixed at rest, an examiner may be able to easily passively move the joint, or active resistance to passive range of motion may be detected. There may be variability of the abnormal posture in different states, without

Psychogenic myoclonus

Psychogenic myoclonus can be challenging to distinguish from organic myoclonus, which is characterized by intermittent random jerks. Patients with psychogenic myoclonus, however, can show distractibility when concentrating on other tasks or may have episodes of myoclonic jerks (Video 4). These patients may also demonstrate an excessive startle response to sensory stimuli, such as loud sounds. The largest reported series of 76 patients with psychogenic axial myoclonus described flexor spasms,

Psychogenic parkinsonism

Psychogenic parkinsonism presents with a variety of clinical signs, including tremor, slowness, and abnormalities of speech and gait.⁴⁹ The tremor often involves the dominant hand and is variable and distractible. There may be spread of tremor to other body parts when the affected limb is restricted. The slowness of movement is characterized by effortful rapid successive movements often associated with grimacing and sighing without a clear decrement of amplitude when performing rapid successive

Psychogenic tics

Psychogenic tics can be challenging to discriminate from organic tics, which can demonstrate features classically associated with PMDS, such as distractibility, suggestibility, and a fluctuating course with spontaneous remissions. One study identified 9 patients with psychogenic motor tics.⁵⁶ No patients had a family or childhood history of organic tics. Compared with Tourette syndrome, patients presenting to the same center during the study period, those with psychogenic tics had an older age

Psychogenic paroxysmal dyskinesia

PMDs often include movements that occur intermittently and episodically and can be categorized as psychogenic paroxysmal dyskinesias. The largest series of psychogenic paroxysmal dyskinesias, involving 26 cases, predominantly women, had a mean age at onset of 38.6 years, later than the typical childhood onset in organic paroxysmal dyskinesias.²¹ The clinical presentation for psychogenic paroxysmal dyskinesia was commonly dystonia in isolation but 69.2% had a combination of movements. Although

Psychogenic gait disorders

Psychogenic gait disorders can have various clinical presentations and are frequently associated with other PMDs. Psychogenic gait disorders need to be distinguished from complex gait patterns than can be seen in dystonia and Huntington disease. Psychogenic patients may have astasia-abasia, characterized by the ability to maintain good balance and even perform tandem gait, despite bizarre contortions and side-to-side swaying of their bodies, without falling (Video 8). They may also have

Other psychogenic movement disorders

Psychogenic chorea has been rarely reported in the literature, in 1 series representing 0.6% of patients with PMDs (Video 9).⁶² A single case report of psychogenic chorea in a patient with a strong family history of Huntington disease highlighted the importance of “anticipation” in patients with this hereditary disease.⁶³ She had choreic movements of the head, arms, and legs that were distractible, markedly diminishing when performing voluntary repetitive movements. She did not have other

Pathophysiology

The pathophysiology of PMDs is not well understood but the traditional view has suggested the contribution of an underlying psychological or physical stress to the development of abnormal movements. Not all patients with PMDs, however, report an underlying stressor. Some investigators have suggested the chief mechanism of psychogenic disorders involves repression of memories and conversion to somatic symptoms.⁶⁹

Structural imaging, such as CT and MRI, are generally unremarkable in patients with

Treatment

Although there is no standard protocol for the treatment of PMDs, several approaches have been suggested, including open and candid communication with patients about the diagnosis at the initiation of treatment.78, 79 Because patients who are accepting of their diagnosis at the onset are more likely to have long-term successful outcomes,⁸⁰ appropriate education is critical. In addition to providing insight to the psychodynamics of the PMD, the authors provide patients with educational materials

Prognosis

Early diagnosis and treatment of PMDs is associated with improved outcome; however, the long-term outcome in PMDs is often poor. In 1 study on the long-term outcome of psychogenic tremor, after a median follow-up of 5.1 years, 64% of patients reported moderate to severe tremor.⁹³ Those with mild or no tremor at follow-up had a shorter duration of symptoms prior to diagnosis. A systematic review of the literature of the prognosis of patients with psychogenic motor symptoms found highly variable

Summary

PMDs represent a group of disorders that are challenging to diagnose and treat. There are many characteristic features of the history as well as classic findings on physical examination that can help clinicians arrive at an accurate diagnosis and avoid unnecessary testing. The diagnosis is not one of exclusion but should be based on supporting features of PMDs. It is important to recognize that PMDs can coexist with organic disease and a skilled clinician must discern between the 2. Ancillary