The flubbed body: Pathological body size representation in personal neglect

Area of Science:

• Neuroscience
• Cognitive Psychology
• Clinical Neurology

Background:

• Personal Neglect (PN) is a body representation disorder often linked to parietal lobe damage.
• Previous research suggests PN involves misrepresentation of body size, particularly the contralesional hand.
• The specificity and generalization of body misrepresentation in PN remain unclear.

Purpose of the Study:

• To investigate the features of hand and face representation in patients with and without PN.
• To determine if body misrepresentation extends beyond the hands to other body parts.
• To explore the relationship between neglect, motor performance, and body representation.

Main Methods:

• A body size estimation task using pictures was administered to 9 right brain-damaged patients (with and without PN) and healthy controls.
• Participants selected images that best matched the perceived size of their hands and face.
• Performance was analyzed to compare body representation across groups.

Main Results:

• Patients with PN (PN+) displayed labile body representations for both hands and face, with a wider range of distortion.
• Patients without PN (PN-) showed misrepresentation of the left contralesional hand, distinct from PN+ patients and controls.
• This misrepresentation in PN- patients may correlate with impaired upper limb motor function.

Conclusions:

• PN is associated with unstable body representations affecting multiple body parts.
• Body representation deficits can exist even in the absence of overt neglect, potentially linked to motor impairments.
• Multisensory integration, including body ownership and motor feedback, is crucial for accurate body size representation.