Neglecting posture: differences in balance impairments between peripersonal and extrapersonal neglect.

Neglect is a heterogeneous disorder and may be specific for only peripersonal or extrapersonal space. Behavioural consequences at the level of independency in basic activities of daily living differ between patients with peripersonal and those with extrapersonal neglect. One of the most important factors that determine independency in basic activities of daily living is balance. Here, potential differences in postural imbalance between patients with peripersonal and those with extrapersonal neglect were investigated. A total of 81 stroke patients were screened within the first 2 weeks after admission to the rehabilitation centre. Mediolateral (horizontal) and anteroposterior (vertical) displacements of the centre of pressure (CoP) were measured using a Nintendo Wii Balance Board in an eyes-open and eyes-closed condition. Patients with peripersonal neglect showed a significant displacement of mediolateral CoP from the ideal CoP, but not in the anteroposterior dimension or postural sway. Patients with extrapersonal neglect did not differ from the no-neglect patients in terms of displacement of both mediolateral and anteroposterior CoP and postural sway. There were no differences between the eyes-open and eyes-closed conditions in any of the groups. Consequences of region-specific neglect on postural imbalance appear to be very specific and cannot be accounted for by neglecting visual information only. The current findings might directly reflect a relation between body perception and body representation and (actions in) peripersonal space. When diagnosing neglect, it is relevant to distinguish the type of region-specific neglect and, when needed, to adjust the rehabilitation programme accordingly.