Post-stroke impairment and recovery are predicted by task-specific regionalization of injury

Absolutely useless, predictions are not what survivors want. THEY WANT RESULTS.   This is predictions assuming the status quo, and the status quo is a COMPLETE FUCKING FAILURE!

Just maybe you want to talk to survivors and not presuppose the tyranny of low expectations you normally use to justify the failure to recover from a stroke. 

Post-stroke impairment and recovery are predicted by task-specific regionalization of injury

Matthew S. Jeffers, Boris Touvykine, Allyson Ripley, Gillian Lahey, Anthony Carter, Numa Dancause and Dale Corbett

Journal of Neuroscience 30 June 2020, JN-RM-0057-20; DOI: https://doi.org/10.1523/JNEUROSCI.0057-20.2020

Abstract

Lesion size and location affect the magnitude of impairment and recovery following stroke, but the precise relationship between these variables and functional outcome is unknown. Herein, we systematically varied the size of strokes in motor cortex and surrounding regions to assess effects on impairment and recovery of function. Female Sprague Dawley rats (N=64) were evaluated for skilled reaching, spontaneous limb use, and limb placement over a 7-week period post-stroke. Exploration and reaching were also tested in a free ranging, more naturalistic, environment. MRI voxel based analysis of injury volume and its likelihood of including the caudal forelimb area (CFA), rostral forelimb area (RFA), hindlimb (HL) cortex (based on intracranial microstimulation), or their bordering regions was related to both impairment and recovery. Severity of impairment on each task was best predicted by injury in unique regions: impaired reaching – by damage in voxels encompassing CFA/RFA, hindlimb placement – by damage in HL, and spontaneous forelimb use – by damage in CFA. An entirely different set of voxels predicted recovery of function: damage lateral to RFA reduced recovery of reaching, damage medial to HL reduced recovery of hindlimb placing, and damage lateral to CFA reduced recovery of spontaneous limb use. Precise lesion location is an important, but heretofore relatively neglected, prognostic factor in both preclinical and clinical stroke studies, especially those employing region-specific therapies such as transcranial magnetic stimulation.

Significance Statement

By estimating lesion location relative to cortical motor representations, we established the relationship between individualized lesion location, and functional impairment and recovery in reaching/grasping, spontaneous limb use, and hindlimb placement during walking. We confirmed that stroke results in impairments to specific motor domains linked to the damaged cortical sub-region and that damage encroaching on adjacent regions reduces the ability to recover from initial lesion-induced impairments. Each motor domain encompasses unique brain regions that are most-associated with recovery and likely represent targets where beneficial reorganization is taking place. Future clinical trials should employ individualized therapies (e.g. TMS, intracerebral stem/progenitor cells) that consider precise lesion location and the specific functional impairments of each subject since these variables can markedly affect therapeutic efficacy.

Footnotes

• This work was supported by a collaborative research grant to D.C. and N.D. from the Heart and Stroke Foundation of Canada. A.R. produced the artwork for each figure. The University of Ottawa Preclinical Imaging Core and Dr. Greg Cron were instrumental for conducting MRI imaging.