Efficacy of mechanisms of neuroplasticity after a stroke

Article type: Research Article

Authors: Cabral, Danylo F.^a | Fried, Peter^b | Koch, Sebastian^c | Rice, Jordyn^a | Rundek, Tatjana^{c; d} | Pascual-Leone, Alvaro^{e; f; g} | Sacco, Ralph^{c; d} | Wright, Clinton B.^h | Gomes-Osman, Joyce^{a; c; d; *}

Affiliations: [a] Department of Physical Therapy, University of Miami, Coral Gables, FL, USA | [b] Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA | [c] Department of Neurology, University of Miami, Miami, USA | [d] Evelyn McKnight Brain Institute, University of Miami, Miami, USA | [e] Department of Neurology, Harvard Medical School, Boston MA, USA | [f] Hinda and Arthur Marcus Institute for Aging Research and Deanna and Sidney Wolk Center for Memory Health, Hebrew SeniorLife, Rosindale, MA, USA | [g] Guttmann Brain Health Institute, Barcelona, Spain | [h] National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA

Correspondence: [*] Corresponding author: Joyce Gomes-Osman, PT, PhD, University of Miami Miller School of Medicine, Department of Neurology, 1150 NW 14th St #609, Miami, 33136, FL, USA. Tel.: +1 305 243 6732; Fax: +1 305 284 6128; E-mail: j.gomes@miami.edu.

Abstract: Background:The sequelae of stoke, including the loss and recovery of function, are strongly linked to the mechanisms of neuroplasticity. Rehabilitation and non-invasive brain stimulation (NIBS) paradigms have shown promise in modulating corticomotor neuroplasticity to promote functional recovery in individuals post-stroke. However, an important limitation to these approaches is that while stroke recovery depends on the mechanisms of neuroplasticity, those mechanisms may themselves be altered by a stroke. Objective:Compare Transcranial Magnetic Stimulation (TMS)-based assessments of efficacy of mechanism of neuroplasticity between individuals post-stroke and age-matched controls. Methods:Thirty-two participants (16 post-stroke, 16 control) underwent an assessment of mechanisms of neuroplasticity, measured by the change in amplitude of motor evoked potentials elicited by single-pulse TMS 10–20 minutes following intermittent theta-burst stimulation (iTBS), and dual-task effect (DTE) reflecting cognitive-motor interference (CMI). In stroke participants, we further collected: time since stroke, stroke type, location, and Stroke Impact Scale 16 (SIS-16). Results:Although there was no between-group difference in the efficacy of TMS-iTBS neuroplasticity mechanism (p = 0.61, η2 = 0.01), the stroke group did not exhibit the expected facilitation to TMS-iTBS (p = 0.60, η2 = 0.04) that was shown in the control group (p = 0.016, η2 = 0.18). Sub-cohort analysis showed a trend toward a difference between those in the late-stage post-stroke and the control group (p = 0.07, η2 = 0.12). Within the post-stroke group, we found significant relationships between TMS-iTBS neuroplasticity and time since stroke onset, physical function (SIS-16), and CMI (all rs > |0.53| and p-values < 0.05). Conclusions:In this proof-of-principle study, our findings suggested altered mechanisms of neuroplasticity in post-stroke patients which were dependent on time since stroke and related to motor function. TMS-iTBS neuroplasticity assessment and its relationship with clinical functional measures suggest that TMS may be a useful tool to study post-stroke recovery. Due to insufficient statistical power and high variability of the data, generalization of the findings will require replication of the results in a larger, better-characterized cohort.

Keywords: Mechanism of neuroplasticity, transcranial magnetic stimulation, iTBS, functional capacity, motor function, stroke

DOI: 10.3233/RNN-211227

Journal: Restorative Neurology and Neuroscience, vol. 40, no. 2, pp. 73-84, 2022