Four legs. Illusory reduplication of the lower limbs after bilateral parietal lobe damage
P. Vuilleumier, A. Reverdin and T. Landis
Department of Neurology, University Hospital of Geneva, Switzerland.
OBJECTIVE: To report an unusual disorder of body schema and its neurologic
and neuropsychological correlates. DESIGN AND METHODS: We describe a
patient with a reduplicative phantom illusion of her lower limbs. Motor and
sensory functions, as well as mental representation of body and space, were
studied during the reduplication experience until its resolution. SETTING:
Clinical neurology department in a primary care hospital. PATIENT: A
64-year-old, left-handed woman who experienced the uncontrollable and
distressing feeling of having 4 legs, without delusional belief, after
surgical removal of a right-predominant parasagittal parietal meningioma.
This phenomenon spontaneously resolved after 2 weeks. INTERVENTION: None.
MAIN OUTCOME MEASURES: Clinical neurologic examinations and standardized
neuropsychological tests, with emphasis on tests assessing orientation to
body parts, right-left discrimination, and mental orientation in space.
RESULTS: The patient had severe weakness and proprioceptive sensory loss in
both lower limbs. She had no disturbances of body schema knowledge but a
striking impairment in tasks requiring mental orientation in space,
particularly for right-left laterality discrimination. Resolution of the
reduplication experience correlated with improvement in the affected
spatial abilities, while motor, sensory, and other cognitive functioning
did not significantly change. CONCLUSION: This patient's reduplicative
phantom illusion might be related to the combination of the severe
somatosensory loss with an underlying impaired mental representation of
relative positions in space.
