Psychogenic Movement Disorders

Certain features may suggest a nonorganic basis for the movement disorder. Features in the history that raise this possibility are the abrupt onset of symptoms and their marked variability in nature or severity over short periods of time. In addition, there is often a marked disparity between symptom severity and the functional limitation to which they reportedly lead. Patients may report that they are unable to work because of their abnormal movements, and yet they can perform the activities of daily living, such as using a personal computer, shopping, cooking, and the like. In other words, any disability is selective. It is also important to enquire about a past history of psychiatric or psychogenic illness and to seek any possible secondary gain, as from pending litigation or workers’ compensation, which may result from the current symptoms.

The examination findings may also be helpful, especially the general appearance and affect of the patient. There may be a combination of different dyskinesias that vary markedly in nature and distribution over time and worsen when formally examined. Other signs of nonorganic neurologic deficits may be present, such as a nonanatomic sensory loss or a lurching unsteady gait that never results in falls.

Psychogenic tremor is typically of variable frequency and can be entrained by such maneuvers as foot tapping. With mental distraction, tremors or other hyperkinetic movement disorders may become more intermittent, variable, or irregular. During skilled movements with the affected limb, they may cease. Loading the limb with weights may increase rather than diminish tremor amplitude. Patients with psychogenic dystonia sometimes report that their symptoms are especially troublesome at rest, whereas organic dystonia is often more conspicuous with volitional activity. In a psychogenic gait disorder, the gait is often very slow, with excessive gesturing and sometimes wild or bizarre motor activity. It typically is quite variable in severity, lessening with distraction and worsening when the patient is observed overtly.

No anatomic correlation can be made, and the neurochemical basis of the movement disorder is unknown. Patients with psychogenic movement disorders typically are unresponsive to appropriate medications, but remission may occur with treatment of the underlying psychiatric disorder. The psychiatric diagnosis may include various somatoform and factitious disorders, depression, anxiety, and histrionic personality disorders. A specific psychiatric diagnosis cannot always be made despite a high index of suspicion for psychogenicity, and the neurologist and psychiatrist may differ in their assessments of the underlying problem.

Investigations may be required to exclude possible organic causes for the patient’s symptoms. Symptoms may have developed on an organic basis and then been perpetuated and elaborated psychogenically. Studies may include brain MRI; serum copper and ceruloplasmin levels and 24-hour urine copper excretion, thyroid function studies, and other tests based on clinical suspicion. The diagnostic evaluation may also include a trial of medications typically used for various organic movement disorders, depending on the patient’s clinical state. Psychiatric referral is then required, with careful follow-up of the patient. Prognosis is variable. Features suggesting a good prognosis are acute onset, short duration of symptoms, healthy premorbid functioning, absence of other organic or psychogenic disorders, and presence of an identifiable precipitant.

Only gold members can continue reading. Log In or Register to continue