Parietal-insular strokes are associated with impaired standing balance as assessed by computerized dynamic posturography

Objective: To identify the location of supratentorial strokes associated with impaired standing balance not due to hemiparesis, proprioceptive deficit, or visual-vestibular abnormality as assessed by computerized dynamic posturography (CDP). Design: Patients with impaired standing balance (ISB group) were identified with initial supratentorial stroke who could stand unassisted with eyes open on a stable platform (CDP condition 1) but could not stand with eyes closed on a sway-referenced platform (CDP condition 5). A second group of patients who could maintain standing balance during both CDP conditions 1 and 5 were selected as controls (control group). Composite CT lesion templates of patients in the ISB group were compared with those of patients in the control group. Setting: An inpatient stroke rehabilitation unit with a mean study entry date of 34 +/- 22 SD days post stroke. Results: The ISB group had significantly more lesions in the insula and subinsular white matter than the control group (p < 0.05). Seventeen of 25 patients in the ISB group (68%) had lesions in the insula or adjacent structures: superior temporal gyrus, frontal operculum, subinsular white matter, putamen. None of eight patients in the control group had lesions in these areas. Conclusions: The parietal-insular cortex of man may represent a cortical integration area necessary for recovery of standing balance during the first two months following supratentorial stroke.