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The Neuroanatomy of Hysterical Paralysis

Hysterical conversion symptoms are transient functional neurologic deficits (e.g., paralysis, blindness, or anesthesia) often triggered by emotional stress. Although they have no known neurologic cause, their facilitation by organic brain disease as well as by mood disorders and their association with neurophysiologic and neuropsychologic abnormalities suggest that conversion symptoms may have an underlying neurobiologic basis. These researchers used SPECT to examine regional cerebral blood flow in 7 patients with unilateral sensorimotor loss due to conversion disorder. The SPECT examination was conducted at rest and during passive vibratory stimulation to both limbs.

All patients showed decreased blood flow in the thalamus and nucleus caudate in the hemisphere contralateral to the symptoms and increased flow in the contralateral lenticular nucleus. Three patients who did not recover showed significantly lower blood flow in the contralateral caudate and thalamus than did the 4 patients who later recovered. Two to four months later, patients who recovered underwent the scan with vibratory stimulation again; blood flow became normal when the deficit resolved. These findings were confirmed by independent statistical and analytic methods.

Comment: These results suggest that conversion disorder is associated with an abnormality in striatothalamocortical circuits controlling sensorimotor function and voluntary movement. These areas have important connections to limbic areas that both process emotional and situational cues and provide reinforcing motivational value to stimuli. These striatal areas also are involved in unilateral motor neglect after organic neurologic damage, when limb movement fails despite lack of true paralysis. Because these areas mediate a wide array of cognitive, emotional, and motor effects, they may serve as a final common pathway for disparate conversion symptoms.

— P Roy-Byrne

Published in Journal Watch Psychiatry July 26, 2001

Citation(s):

Vuilleumier P et al. Functional neuroanatomical correlates of hysterical sensorimotor loss. Brain 2001 Jun 124 1077-1090.

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• Inspirational
  Anita Mahajan, Sir Ganga Ram Hospital Delhi,India, 10 Mar 2010 3:35 PM EST
  My favourite topic, few references of good value available. Two step examination as well as follow up makes it a... [more]

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