Body Representation Alterations in Patients with Unilateral Brain Damage.

OBJECTIVE: Systematic studies about the impact of unilateral brain damage on the different body representations (body schema, body structural representation, and body semantics) are still rare. Aim of this study was to evaluate body representation deficits in a relatively large sample of patients with unilateral brain damage and to investigate the impact of right or left brain damage on body representations (BRs), independently from deficits in other cognitive processes. METHOD: Sixty-four patients with unilateral stroke (22 with left brain damage, LBD; 31 with right brain damage without neglect, RBD-N; 11 with right brain damage with neglect, RBD+N) and 41 healthy individuals underwent a specific battery including BR as well as control tasks. RESULTS: In more than a third of the sample, selective (37.5%) and pure (31%) deficits of BR were presented and equally distributed among the different BRs (˜10% for each representation), with selective (27.2%) and pure (22.7%) body schema deficit mainly presented after left brain damage. As a group, patients with unilateral brain damage, independently of the side of lesion (LBD, RBD-N, RBD+N), had significantly worse performance on body structural representation with respect to healthy individuals, whereas LBD had numerically worse performance on body schema with respect to healthy individuals and RBD-N. No significant differences among groups were found on body semantics. CONCLUSION: BR deficits are not a rare consequence of unilateral brain damage and are independent of a more general cognitive dysfunction. Accordingly, the need for an accurate assessment and specific neuropsychological training in clinical settings is discussed.

Interoceptive awareness in focal brain-damaged patients.

BACKGROUND: Interoception is the basic process enabling evaluation of one's own internal state of body, but its alteration in brain-damaged patients has not been adequately investigated. Our study aimed to investigate awareness of visceral and somatosensorial sensations in brain-damaged patients with unilateral stroke. METHODS: Sixty patients (22 with left brain damage, LP; 25 with right brain damage without neglect, RPN-; and 13 with right brain-damage and extrapersonal and/or personal neglect, RPN+) and 45 healthy controls (HC) completed the Self-Awareness Questionnaire (SAQ), a self-report tool for assessing interoceptive awareness with two domains related to visceral (VD) and somatosensory feelings (SD), respectively. RESULTS: Comparing the SAQ subdomains scores between three groups of patients (LP, RPN-, and RPN+) and HC, we found that RPN+ had significantly lower scores on VD than HC and LP, whereas no significant difference was found on scores of SD between groups. CONCLUSION: Our results support the hypothesis of a right-hemispheric dominance for "interoceptive neural network" suggesting that processing of visceral sensations would be located mainly in the right hemisphere. Therefore, a careful assessment of interoceptive awareness in clinical practice would be useful to improve rehabilitation and to engage patients with deficit of interoceptive awareness in developing greater accuracy of body signals.

Drawing with oblique coordinates: on a single case.

We describe a patient with right hemisphere damage affected by mild left visuo-spatial neglect and constructional apraxia. During the rehabilitation, he failed to draw a draught-board using horizontal and vertical trajectories, but he performed it successfully using oblique trajectories. These observations suggested an impairment of vertical/horizontal spatial coordinates system. In copying tasks including figure elements in different orientations he drew more accurately components in oblique orientation, whereas failed to reproduce components in horizontal orientation. The patient performed visuospatial perceptual and perceptual-imaginative tasks successfully. From these findings, it is possible to suggest that the oblique coordinate system of reference operates independently of vertical and horizontal coordinate systems in building a complex figure and that, therefore, cardinal orientation do not constitute a reference norm to define oblique orientation, as previously suggested.

Persistent left unilateral mirror writing: A neuropsychological case study.

Mirror writing (MW) is a rare disorder in which a script runs in direction opposite to normal and individual letters are reversed. The disorder generally occurs after left-hemisphere lesions, is transient and is observed on the left hand, whereas usually motor impairments prevent assessment of direction of right handwriting. We describe a left-handed patient with complete left hand mirror writing, still evident 2 years after a hemorrhagic stroke in left nucleo-capsular region. Since the patient could write with his right hand he underwent several writing tasks with either hand, and a thorough assessment to clarify the nature of MW. MW was evident in writing to dictation with left hand only, both in right and left hemispace, but the patient could modify his behavior when a verbal instruction was provided. No mirror errors were found in reading words, in copying geometric figures and in spatial orientation tasks. MW in our patient could be accounted for by a failure in automatic transformation of grapho-motor programs to write with the left hand. A lack of concern (a sort of anosodiaphoria) and a poor cognitive flexibility could contribute to long-term persistence of MW.