Session Information
Session Title: AA 2021 Virtual Posters - Neurological Rehabilitation
Session Time: None. Available on demand.
Disclosures: Colleen L. Schneider, PhD: No financial relationships or conflicts of interest
Objective: To relate vision recovery after stroke with the change in voxel receptive field size in early visual cortex using functional magnetic resonance imaging (fMRI).
Design: ProspectiveSetting : Tertiary care hospitalParticipants : 14 stroke patients with hemianopia, studied at multiple time points in the first 6 months post-stroke
Interventions: Not applicable
Main Outcome Measures: Change in ability to detect a letter at each of 72 visual field locations from one timepoint to the next (stably blind, recovered vision, stably sighted) as a function of the relative change in the size of the receptive field of each early visual cortex voxel (size at tn / size at tn-1).
Results: Across patients, the average (± standard deviation) receptive field expansion for voxels representing the affected hemifield was 2.4±1.34 for stably blind locations, 1.99±0.84 for recovered locations and 1.63±0.36 for stably sighted locations compared to 1.37±0.29, 1.58±0.39, and 1.54±0.32, respectively for mirror image locations in the unaffected hemifield. A two-way repeated-measures ANOVA revealed a significant interaction between hemifield and change-in-vision (F(2,20)=6.64, p=0.006). Receptive fields representing stably blind locations expanded more than their mirror image counterparts in the unaffected hemifield (t(10)=2.47, p=0.03), but there was no difference for recovered or stably sighted locations in the affected hemifield and their mirror image counterparts (t(13)=1.54, p=0.15; t(13)=0.73, p=0.48, respectively). A one-way repeated measures ANOVA on change-in-vision in the hemianopic hemifield was significant (F(1,12)=5.24, p=0.04), with a significant difference between all change-in-vision pairs in the affected hemifield (all p < 0.05). There was no significant difference between the three mirror image change-in-vision counterparts in the unaffected hemifield (F(2,20)=1.36, p=0.28).Conclusions: Receptive field expansion was greatest for voxels that represented stably blind locations of the visual field, while recovered locations had a medium amount of expansion. This difference may suggest that, like motor recovery, successful vision recovery post-stroke requires two steps: expansion of the cortical representation followed by pruning.
Level of Evidence: Level I
To cite this abstract in AMA style:
Schneider CL, Prentiss E, Sahin B, Mahon B, Busza A, Williams Z. In Hemianopic Stroke Patients, Poor Vision Recovery Is Associated with Enduring Expansion of the Cortical Representation of the Original Blind Field [abstract]. PM R. 2021; 13(S1)(suppl 1). https://pmrjabstracts.org/abstract/in-hemianopic-stroke-patients-poor-vision-recovery-is-associated-with-enduring-expansion-of-the-cortical-representation-of-the-original-blind-field/. Accessed January 18, 2025.« Back to AAPM&R Annual Assembly 2021
PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/in-hemianopic-stroke-patients-poor-vision-recovery-is-associated-with-enduring-expansion-of-the-cortical-representation-of-the-original-blind-field/