Theory Report
Population: Adult
Lara A Boyd, PT, PhD, Professor, University of British Columbia lara.boyd@ubc.ca
Kathryn Hayward, PT PhD, Postdoctoral Fellow, University of British Columbia; University of Melbourne kathryn.hayward@ubc.ca
Julie Bernhardt, PT PhD, Professor, University of Melbourne; La Trobe University j.bernhardt@unimelb.edu.au
Katie Wadden, MSc, PhD Candidate, University of British Columbia k.wadden@alumni.ubc.ca
Sue Peters, PT, PhD Candidate, University of British Columbia s.peters@alumni.ubc.ca
Keywords: Prediction, Stroke, Somatosensation, MRI
Upper limb disability has been identified as one of the Top 10 research priorities for life after stroke. The population of stroke survivors with severe upper limb disability is rising and they have been historically identified to have the poorest prognosis for optimal recovery. This is likely underpinned by the fact that they often lack an important neuroimaging indicator of recovery potential, that is, sufficient projections arising from the posterior limb of the corticospinal tract (PLIC) using diffusion tensor imaging (DTI). However, there are reports that this cohort can achieve positive functional outcomes in response to intensive task-oriented training administered beyond 6-months post stroke. This would suggest that there is some degree of untapped recovery potential that is unrecognized. It would therefore, appear timely to explore how we can accurately identify the recovery potential of stroke survivors with severe upper limb disability earlier post stroke. We propose that it is the collective integrity of the remaining brain networks, derived from multimodal neuroimaging, which will enable the best identification of recovery potential in people with severe upper limb disability. A single indicator derived from an isolated bundle of fibre projections (i.e. PLIC) is likely to be insufficient in identifying the ‘true’ recovery potential of an individual with severe disability. Studies from our laboratory have demonstrated that optimal recovery is related to functional networks and available fibre projections beyond the PLIC. As such, in people with little to no measurable projections from the PLIC, it is likely to be even more pertinent to explore the collective integrity of the remaining brain networks. By moving from a singular neuroimaging indicator (e.g. DTI) to a multimodal indicator (e.g. DTI + resting state functional magnetic resonance imaging + myelin water imaging), we will be able to explore the role of the individuals’ whole brain network to more accurately identify the recovery potential of stroke survivors with severe upper limb disability after stroke. Given that the optimal time window to exploit recovery potential remains unknown, a longitudinal approach is necessary to explore the dynamic capacity of the severely damaged brain. In doing so, natural recovery will also be documented and will provide the foundations to explore the additive value of novel training approaches that seek to maximise an individual’s recovery potential. Failure to identify the recovery potential of people with severe upper limb disability limits the clinician’s ability to support achievement of optimal recovery and quality of life. Currently, we are undertaking a longitudinal cohort study of stroke survivors with severe upper limb disability who are recruited early post stroke (2-4 weeks) and followed up at 3-, 6-, and 12-months post stroke. We are adopting the proposed multimodal neuroimaging approach to explore the role of the individual’s residual brain network to achievement of optimal recovery after stroke. At the STEP-IV Meeting we will present preliminary data.
Citation:
Boyd, Lara A, PT, PhD; Hayward, Kathryn S, PT PhD; Bernhardt, Julie , PT PhD; Wadden, Katie P, MSc; Peters, Sue , PT. Identifying recovery potential of stroke survivors with severe upper limb disability: The need for multimodal neuroimaging.. Poster Presentation. IV STEP Conference, American Physical Therapy Association, Columbus, OH, July 17, 2016. Online. https://u.osu.edu/ivstep/poster/abstracts/079_boyd-et-al/