Stroke is a growing cardiovascular concern in the United States, with approximately 7 million individuals reporting
a stroke event. Stroke is a particular concern in the South Texas Rio Grande Valley, where incidence is
approximately 3.8% (compared to 0.27% in the general population). Common limitations after a stroke include:
gait instability, upper limb paralysis, sensory deficits, pain, depression and cognitive impairments. Of all
impairments, paresis of the upper and lower limb remains the most common. Rehabilitation strategies can
improve upper and lower limb mobility in stroke survivors. Unfortunately, though, the majority of rehabilitation
strategies employ a ‘one-size-fits-all’ approach, thereby limiting efficacy in the heterogenous stroke population.
To address this limitation, the use of biomarkers has emerged as a means to inform patient selection for the
differing rehabilitation approaches.
In general, biomarkers have focused on how changes in corticospinal tract structure or function influence
recovery. Overall, published work has suggested that changes to the corticospinal tract pathways in the brain
may influence functional recovery in patients with stroke. However, current rehabilitation approaches targeting
spared corticospinal pathways have had limited efficacy in patient populations, particularly those with severe
impairments. Therefore, it is vital to understand what other pathways beyond the corticospinal tract may influence
functional recovery as to better inform clinical treatment of patients with stroke.
Here, we propose to evaluate the progression of alternate sensorimotor pathway degeneration in patients
with stroke by imaging the brainstem and spinal cord, where the sensorimotor pathways diverge. To evaluate
our premise, we will perform a longitudinal, repeated-measures clinical study in 30 subjects with acute ischemic
stroke. We will evaluate sensorimotor pathway neurodegeneration in the cervical, thoracic and lumbar spinal
cord and in the brainstem by collecting magnetic resonance imaging (MRI) and diffusion weighted imaging (DWI)
at two-, twelve- and twenty-four weeks post-stroke. Neuroimaging will also be collected in 10 age-matched
healthy controls. Our aims will: (1) evaluate alternate sensorimotor pathway neurodegeneration in the brain
stem and (2) spinal cord and (3) determine how neurodegeneration affects motor function and impairment in
acute stroke patients. Our central hypothesis is that degeneration of the alternate sensorimotor pathways is
progressive after a first-time stroke and will affect both the lesioned and non-lesioned hemisphere pathways to
significantly impact motor function.
The results from our study will provide the basis for larger-scale clinical trials evaluating alternate
sensorimotor pathway degeneration. Further, our work will provide the framework for whether treatment options
targeting alternate sensorimotor pathways should be considered in populations with acute stroke.