Abstract WP200: Deficits in Proprioception Associated With Supramarginal Gyrus Lesions After Stroke - A Case Series Approach

Abstract

Proprioception is our sense of limb position and movement without vision. Impaired proprioception leads to difficulty performing activities of daily living. While proprioceptive deficits are common after stroke, the neural correlates underlying them are relatively unknown. Recent voxel based lesion analysis evidence suggests that a cluster of regions is implicated in these deficits, including the supramarginal gyrus (SMG) and S1. Using a case series approach, we assessed the impact of different lesion combinations on proprioception, encapsulating SMG with and without S1 and other brain regions in this network. Robotic assessments of proprioception (position matching and kinaesthesia) and MRI/CT scans were acquired for 217 individuals around 1-week post stroke. Across both robotic assessments, performance was compared to a normative model of healthy controls to detect the presence of proprioceptive deficits. Lesions on scans were marked by a trained assessor and then verified by a neurologist. Individuals with lesions to combinations of SMG, S1, insula and operculum were extracted. The extent of damage to each region was determined using the Automated Anatomical Labelling and Catani atlases. A total of 62 subjects with lesion combinations of interest were identified and analysed in more detail (13 SMG lesions). The extent of SMG damage was small, ranging from 0.03% to 25.95%. Position sense deficits were common for both right (6/6) and left SMG (6/7) lesions. Even in the absence of S1 lesions, these deficits remained prevalent. Deficits in kinaesthesia were more common in individuals with combined SMG and S1 lesions than in those without concurrent S1 lesions. Deficits in both proprioceptive assessments were uncommon in those with left S1 lesions in the absence of SMG lesions. Those with right S1 lesions displayed greater deficits than those with left S1 lesions. Results indicate that brain areas beyond S1 must be considered to better understand proprioceptive deficits and develop better strategies for improving proprioceptive function after stroke. The contributory influence of each area should be further explored in isolation.