Mirror asomatognosia in right lesions stroke victims

The objectives of this prospective study were: to search for mirror-induced disorders of the body image in right hemisphere stroke victims using a description task of the contralateral upper limb, to analyze their clinical features, and to discuss possible mechanisms. Sixteen consecutive patients with documented unilateral right hemisphere stroke were examined for asomatognosia at the acute phase of stroke, then at least 2 months after stroke under three test conditions: without a mirror, with a conventional mirror, with an inverted mirror. Video recordings of the tests were analyzed to assess performance. The diagnosis of asomatognosia was retained if the subject reported at least one of three sensations: limb transformation, limb strangeness, and/or limb alienation. During the acute phase, 14/16 patients presented manifestations of asomatognosia. All of these spontaneous manifestations had disappeared 2 months later, but were reactivated in 12 patients when exposed to mirror images. The mirror tests revealed four situations: no disorder (n = 4), asomatognosia with both mirrors (n = 5), asomatognosia with the conventional or inverted mirrors (n = 1 and 5), and asomatognosia with the inverted mirror (n = 1). These manifestations were designated as mirror-asomatognosia, a disorder resulting from adaptations of the procedures leading to reorganization of the internal representations of the body image. These findings suggest there are several such internal representations of the body image and that direct body image and mirror body image would be two specific ones. These clinical manifestations and their evolution over time are an expression of the progressive nature of the underlying compensatory mechanisms made possible by brain plasticity.