42 Psychogenic Movement Disorders

Diana Apetauerova

Clinical Vignette

A 35-year-old woman with a medical history of depression presented with intermittent head tremor. Several months ago while driving, with her seat belt on, and stopped at a traffic signal she had a motor vehicle accident (MVA) when her car was rear ended. She had no immediate overt injuries, but did complain of mild neck pain after that. Subsequently, just 3 weeks later, she first noted tremor. Her tremor was fairly persistent and did not improve after drinking alcoholic beverages or disappear at night. She “had to leave work” due to this tremor; she then filed formal litigation against the offending driver. Her family history included a younger brother with dystonic cerebral palsy. This patient used fluoxetine (Prozac) long-term for her depression.

This patient appeared very anxious; however, her general physical examination was unremarkable. Her neurologic examination demonstrated an intermittent shaking horizontal “no–no” head posture as well as “yes–yes” vertical tremor of her head. The tremor continually changed in frequency as well as amplitude; there was no consistent pattern evident; that is, it was consistently inconsistent. She had no dystonic posturing or hypertrophy of any neck muscles. Her tremor became very prominent while discussing the details of the MVA and completely disappeared when she was deliberately distracted. Similarly, the tremor was totally absent during other portions of the neurologic examination. However, her muscle strength testing also demonstrated consistently inconsistent “weakness” of the “give way” type typical of nonorganic secondary gain patients. The remainder of her examination was unremarkable. She did not have any tremor in other body parts, nor any cogwheeling, rigidity, or signs of dystonia. While ambulating, her head tremor again became very prominent.

Laboratory testing for Wilson disease, thyroid, vitamin B₁₂ level, head and neck magnetic resonance imaging (MRI), and magnetic resonance angiography were all normal. With her consistently inconsistent neurologic findings, a diagnosis of psychogenic tremor was suspected. Several treatment options including propranolol, anxiolytics, and antidepressants were tried without either objective or subjective improvement. Later, after undergoing psychotherapy, she experienced a sudden and complete remission of these symptoms.

Psychogenic, psychosomatic, hysterical, or functional movement disorders are conditions related to an underlying psychiatric illness with no evidence of any organic etiology. One has to be very cautious. There is a major inherent difficulty whenever one entertains a diagnosis of a psychogenic movement disorder as studies demonstrate that this is a too common and poorly documented diagnosis, in that up to 30% of patients diagnosed with psychogenic disorders eventually are found to have an organic neurologic illness, Because, with just a few exceptions, most movement disorders have no specific diagnostic laboratory or imaging study available, beyond clinical observation, there is a temptation by the uninitiated to label a patient hysterical when the clinician cannot arrive at a definitive organic diagnosis. An important diagnostic caveat is for the evaluating physician to not rush to judgment when the patient’s findings do not initially fit a specific diagnostic set, such as pill-rolling rest tremor, cogwheel rigidity, masked facies, and en bloc walking as is typical of Parkinson disease. Astute clinicians often use a “tincture of time” to prospectively and carefully follow patients by repeated clinical evaluations. Here one monitors the individual patient for the gradual development of recognized classic signs of an evolving and well-recognized neurologic process. Barring the later clinical evolution of symptoms and findings into a more classic organic movement disorder, the clinician will gradually acquire information from the patient or family to become more comfortable with the importance of underlying psychogenic factors.

A variety of underlying psychiatric diagnoses are found in patients with psychogenic neurologic movement disorders; these include various somatoform and factitious disorders, malingering, depression, anxiety, and histrionic personality disorders. Although a specific psychiatric diagnosis cannot always be confirmed for these various abnormal and consistently inconsistent motor symptoms, despite the clinician’s high suspicion of psychogenicity, an emotionally based diagnosis is not totally precluded. Often it is only time and a cautious diagnostic approach that will allow one to sort out the majority of these challenging patients’ specific diagnosis. In young women, one has to be particularly careful to not overlook sexual abuse, particularly incest.

Psychogenic tremor, dystonia, myoclonus, chorea, and parkinsonism are the typical means for a functional movement disorder to present and are particularly common in women (Fig. 42-1

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