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Principal Investigator: Clayton Swanson
Organization: VETERANS HEALTH ADMINISTRATION
Fiscal Year: 2024
Funding agency: Veterans Affairs
The objective of this CDA-1 proposal is to launch my independent research career in the area of mobility function
and rehabilitation in Veterans with neurological impairments. Specifically, I am interested in the neural control of
turning while walking, which is often impaired for older adults and people who have had a stroke. Leveraging my
prior training and experience in assessing and analyzing turning performance, I am proposing to expand my
skillset by adding training in clinical trials, neuroimaging, and neuromodulation. I have assembled a mentoring
team of experts in these particular fields who hold faculty appointments at Malcom Randall VA Medical Center
and the University of Florida. This CDA-1 proposal is supported by the infrastructure of Dr. David Clark’s (primary
mentor) ongoing Merit Review study that aims to determine the effects of prefrontal transcranial direct current
stimulation (tDCS) in augmenting complex locomotor learning in older adults with mobility impairment. Recent
research from Clark and colleagues indicates that the prefrontal cortical networks play a critical role in the control
of complex walking tasks and the acquisition and consolidation of new motor skills (as suggested by
neuroimaging and neuromodulation studies). These findings provide the scientific basis for the parent Merit
Review study and supports the innovative use of tDCS as an adjuvant to enhance training for complex walking
tasks. Dr. Clark’s novel complex locomotor learning protocol trains study participants to practice complex walking
tasks such as walking over obstacles, over compliant (soft) terrain, and turning. While assessing a variety of
functional gait measures, the parent Merit Review study does NOT include turning as an outcome measure.
Turning assessments proposed in this CDA-1 will be a novel addition to the study. Notably, turning is a complex
movement requiring neural control, movement planning, dynamic balance, and coordination. From the moment
we wake up, to when we fall asleep, nearly half of our steps incorporate some degree of a turn, which can result
in serious injury if performed poorly. For instance, a fall while turning is eight times more likely to result in a hip
fracture compared to a fall while walking straight ahead. Additionally, prolonged 360˚ turn duration in older adults
is strongly associated with increased fall risk, loss of independence, and reduced walking speed. However, our
understanding of the specific characteristics and mechanisms of declines in turning function remain poorly
understood, and the potential for restoration of turning function is uncertain. The proposed CDA-1 will study
whether tDCS combined with a complex walking intervention can specifically enhance turning performance.
Therefore, the objective of this proposal is to elucidate whether tDCS and complex locomotor learning can
enhance turning performance and furthermore, identify associations between gains in turning performance and
baseline measures of cognitive function, neuroanatomical structure and function (measured with magnetic
resonance imaging; MRI), and [neurophysiological function (measured with transcranial magnetic stimulation;
TMS)]. Specific Aim 1 will test the hypothesis that turn related performance gains and retention for the 360˚ and
180˚ turns will be greater for the active tDCS group vs. the sham tDCS group. To test this, we will measure
turning performance at four distinct timepoints (baseline, 1-day, 1-week, and 1-month post intervention) using
wireless inertial sensors. Specific Aim 2 will test the hypothesis that larger turning improvements on the 360˚
and 180˚ turn tests will be associated with – greater baseline working memory (2a), greater baseline gray matter
volume (2b), and greater baseline functional network connectivity (2c). [Specific Aim 3 will test the hypothesis
that participants with greater baseline cortical inhibition (measured by TMS) will demonstrate larger 360˚ and
180˚ turning performance gains.] This pilot study will enroll 40 mobility compromised older adults and 10
participants post-stroke which will provide preliminary data for a future CDA-2 grant submission, proposing a
larger scale clinical trial of turning rehabilitation for mobility compromised Veterans. The long-term objectives of
this research are to improve turning performance, mitigate fall risk, and improve the quality of life for Veterans.
Terms: <21+ years old><65 and older><65 or older><65 years of age and older><65 years of age or more><65 years of age or older><65+ years><65+ years old><> 65 years><Accounting><Address><Adjuvant><Adult><Adult Human><Aged 65 and Over><Aging><Anodes><Apoplexy><Appointment><Area><Award><Behavior assessment><Bilateral><Brain><Brain Nervous System><Brain Vascular Accident><Cathodes><Cerebral Stroke><Cerebrovascular Apoplexy><Cerebrovascular Stroke><Characteristics><Clinical><Clinical Trials><Complex><Corticospinal Tracts><Data><Decline in mobility><Decrease in mobility><Decreased mobility><Diminished mobility><E-stim><Elderly><Electric Stimulation><Electrodes><Encephalon><Enrollment><Equilibrium><Faculty><Florida><Future><Gait><Goals><Grant><Hip Fractures><Immediate Memory><Impairment><Incidence><Individual Differences><Infrastructure><Injury><Intervention><Intervention Strategies><Knowledge><Learning><Left><Lower Extremity><Lower Limb><MR Imaging><MR Tomography><MRI><MRI Scans><MRIs><Magnetic Resonance Imaging><Magnetic Resonance Imaging Scan><Measures><Medical Imaging, Magnetic Resonance / Nuclear Magnetic Resonance><Medical Rehabilitation><Medical center><Membrum inferius><Mentors><Mobility decline><Mobility impairment><Motor Skills><Movement><NMR Imaging><NMR Tomography><Neuranatomies><Neuranatomy><Neuroanatomies><Neuroanatomy><Neurologic><Neurological><Nuclear Magnetic Resonance Imaging><Outcome><Outcome Measure><Parents><Participant><Performance><Persons><Pilot Projects><Play><Prefrontal Cortex><Protocol><Protocols documentation><QOL><Quality of life><Randomized><Reduced mobility><Reduction in mobility><Rehabilitation><Rehabilitation therapy><Research><Rest><Risk><Role><Sampling><Scalp><Scalp structure><Short-Term Memory><Shortterm Memory><Stroke><Structure><Task Performances><Testing><Time><Training><Transcranial magnetic stimulation><Universities><Veterans><Walking><Zeugmatography><above age 65><adulthood><advanced age><after age 65><after stroke><age 65 and greater><age 65 and older><age 65 or older><age > 65><age of 65 years onward><aged><aged 65 and greater><aged 65+><aged ≥65><balance><balance function><behavioral assessment><body movement><brain attack><career><career development><cerebral vascular accident><cerebrovascular accident><cognitive assessment><cognitive function><cognitive testing><design><designing><electrostimulation><enroll><experience><fall risk><falls><geriatric><gray matter><human old age (65+)><improved><injuries><innovate><innovation><innovative><interest><interventional strategy><locomotor learning><measurable outcome><mobility rehab><mobility rehabilitation><motor learning><neural><neural circuit><neural circuitry><neural control><neural imaging><neural mechanism><neural regulation><neuro-imaging><neurocircuitry><neuroimaging><neurological imaging><neuromechanism><neuromodulation><neuromodulatory><neurophysiological><neurophysiology><neuroregulation><non-invasive brain stimulation><noninvasive brain stimulation><novel><old age><older adult><older adulthood><outcome measurement><over 65 years><parent><pilot study><post intervention><post stroke><poststroke><primary outcome><randomisation><randomization><randomly assigned><rehab therapy><rehabilitative><rehabilitative therapy><restoration><senior citizen><sensor><skills><social role><stroke hemiparesis><stroke survivor><stroked><strokes><substantia grisea><synaptic circuit><synaptic circuitry><transcranial direct current stimulation><walking intervention><walking pace><walking speed><wireless><working memory><≥65 years>