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  • 1
    In: Brain Communications, Oxford University Press (OUP), Vol. 3, No. 4 ( 2021-10-01)
    Abstract: Up to two-thirds of stroke survivors experience persistent sensorimotor impairments. Recovery relies on the integrity of spared brain areas to compensate for damaged tissue. Deep grey matter structures play a critical role in the control and regulation of sensorimotor circuits. The goal of this work is to identify associations between volumes of spared subcortical nuclei and sensorimotor behaviour at different timepoints after stroke. We pooled high-resolution T1-weighted MRI brain scans and behavioural data in 828 individuals with unilateral stroke from 28 cohorts worldwide. Cross-sectional analyses using linear mixed-effects models related post-stroke sensorimotor behaviour to non-lesioned subcortical volumes (Bonferroni-corrected, P  & lt; 0.004). We tested subacute (≤90 days) and chronic (≥180 days) stroke subgroups separately, with exploratory analyses in early stroke (≤21 days) and across all time. Sub-analyses in chronic stroke were also performed based on class of sensorimotor deficits (impairment, activity limitations) and side of lesioned hemisphere. Worse sensorimotor behaviour was associated with a smaller ipsilesional thalamic volume in both early (n = 179; d = 0.68) and subacute (n = 274, d = 0.46) stroke. In chronic stroke (n = 404), worse sensorimotor behaviour was associated with smaller ipsilesional putamen (d = 0.52) and nucleus accumbens (d = 0.39) volumes, and a larger ipsilesional lateral ventricle (d = −0.42). Worse chronic sensorimotor impairment specifically (measured by the Fugl-Meyer Assessment; n = 256) was associated with smaller ipsilesional putamen (d = 0.72) and larger lateral ventricle (d = −0.41) volumes, while several measures of activity limitations (n = 116) showed no significant relationships. In the full cohort across all time (n = 828), sensorimotor behaviour was associated with the volumes of the ipsilesional nucleus accumbens (d = 0.23), putamen (d = 0.33), thalamus (d = 0.33) and lateral ventricle (d = −0.23). We demonstrate significant relationships between post-stroke sensorimotor behaviour and reduced volumes of deep grey matter structures that were spared by stroke, which differ by time and class of sensorimotor measure. These findings provide additional insight into how different cortico-thalamo-striatal circuits support post-stroke sensorimotor outcomes.
    Type of Medium: Online Resource
    ISSN: 2632-1297
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 3020013-1
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  • 2
    In: Journal of the American Heart Association, Ovid Technologies (Wolters Kluwer Health), Vol. 11, No. 10 ( 2022-05-17)
    Abstract: Persistent sensorimotor impairments after stroke can negatively impact quality of life. The hippocampus is vulnerable to poststroke secondary degeneration and is involved in sensorimotor behavior but has not been widely studied within the context of poststroke upper‐limb sensorimotor impairment. We investigated associations between non‐lesioned hippocampal volume and upper limb sensorimotor impairment in people with chronic stroke, hypothesizing that smaller ipsilesional hippocampal volumes would be associated with greater sensorimotor impairment. Methods and Results Cross‐sectional T1‐weighted magnetic resonance images of the brain were pooled from 357 participants with chronic stroke from 18 research cohorts of the ENIGMA (Enhancing NeuoImaging Genetics through Meta‐Analysis) Stroke Recovery Working Group. Sensorimotor impairment was estimated from the FMA‐UE (Fugl‐Meyer Assessment of Upper Extremity). Robust mixed‐effects linear models were used to test associations between poststroke sensorimotor impairment and hippocampal volumes (ipsilesional and contralesional separately; Bonferroni‐corrected, P 〈 0.025), controlling for age, sex, lesion volume, and lesioned hemisphere. In exploratory analyses, we tested for a sensorimotor impairment and sex interaction and relationships between lesion volume, sensorimotor damage, and hippocampal volume. Greater sensorimotor impairment was significantly associated with ipsilesional ( P =0.005; β=0.16) but not contralesional ( P =0.96; β=0.003) hippocampal volume, independent of lesion volume and other covariates ( P =0.001; β=0.26). Women showed progressively worsening sensorimotor impairment with smaller ipsilesional ( P =0.008; β=−0.26) and contralesional ( P =0.006; β=−0.27) hippocampal volumes compared with men. Hippocampal volume was associated with lesion size ( P 〈 0.001; β=−0.21) and extent of sensorimotor damage ( P =0.003; β=−0.15). Conclusions The present study identifies novel associations between chronic poststroke sensorimotor impairment and ipsilesional hippocampal volume that are not caused by lesion size and may be stronger in women.
    Type of Medium: Online Resource
    ISSN: 2047-9980
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2022
    detail.hit.zdb_id: 2653953-6
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  • 3
    In: Journal of Electromyography and Kinesiology, Elsevier BV, Vol. 41 ( 2018-08), p. 9-18
    Type of Medium: Online Resource
    ISSN: 1050-6411
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2018
    detail.hit.zdb_id: 2006766-5
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  • 4
    In: Neurology, Ovid Technologies (Wolters Kluwer Health), Vol. 100, No. 20 ( 2023-05-16), p. e2103-e2113
    Abstract: Functional outcomes after stroke are strongly related to focal injury measures. However, the role of global brain health is less clear. In this study, we examined the impact of brain age, a measure of neurobiological aging derived from whole-brain structural neuroimaging, on poststroke outcomes, with a focus on sensorimotor performance. We hypothesized that more lesion damage would result in older brain age, which would in turn be associated with poorer outcomes. Related, we expected that brain age would mediate the relationship between lesion damage and outcomes. Finally, we hypothesized that structural brain resilience, which we define in the context of stroke as younger brain age given matched lesion damage, would differentiate people with good vs poor outcomes. Methods We conducted a cross-sectional observational study using a multisite dataset of 3-dimensional brain structural MRIs and clinical measures from the ENIGMA Stroke Recovery. Brain age was calculated from 77 neuroanatomical features using a ridge regression model trained and validated on 4,314 healthy controls. We performed a 3-step mediation analysis with robust mixed-effects linear regression models to examine relationships between brain age, lesion damage, and stroke outcomes. We used propensity score matching and logistic regression to examine whether brain resilience predicts good vs poor outcomes in patients with matched lesion damage. Results We examined 963 patients across 38 cohorts. Greater lesion damage was associated with older brain age (β = 0.21; 95% CI 0.04–0.38, p = 0.015), which in turn was associated with poorer outcomes, both in the sensorimotor domain (β = −0.28; 95% CI −0.41 to −0.15, p 〈 0.001) and across multiple domains of function (β = −0.14; 95% CI −0.22 to −0.06, p 〈 0.001). Brain age mediated 15% of the impact of lesion damage on sensorimotor performance (95% CI 3%–58%, p = 0.01). Greater brain resilience explained why people have better outcomes, given matched lesion damage (odds ratio 1.04, 95% CI 1.01–1.08, p = 0.004). Discussion We provide evidence that younger brain age is associated with superior poststroke outcomes and modifies the impact of focal damage. The inclusion of imaging-based assessments of brain age and brain resilience may improve the prediction of poststroke outcomes compared with focal injury measures alone, opening new possibilities for potential therapeutic targets.
    Type of Medium: Online Resource
    ISSN: 0028-3878 , 1526-632X
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2023
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  • 5
    Online Resource
    Online Resource
    SAGE Publications ; 2018
    In:  Neurorehabilitation and Neural Repair Vol. 32, No. 12 ( 2018-12), p. 1020-1030
    In: Neurorehabilitation and Neural Repair, SAGE Publications, Vol. 32, No. 12 ( 2018-12), p. 1020-1030
    Abstract: Background. Studies in neurologically intact subjects suggest that the gradual presentation of small perturbations (errors) during learning results in better transfer of a newly learned walking pattern to overground walking. Whether the same result would be true after stroke is not known. Objective. To determine whether introducing gradual perturbations, during locomotor learning using a split-belt treadmill influences learning the novel walking pattern or transfer to overground walking poststroke. Methods. Twenty-six chronic stroke survivors participated and completed the following walking testing paradigm: baseline overground walking; baseline treadmill walking; split-belt treadmill/adaptation period (belts moving at different speeds); catch trial (belts at same speed); post overground walking. Subjects were randomly assigned to the Gradual group (gradual changes in treadmill belts speed during adaptation) or the Abrupt group (a single, large, abrupt change during adaptation). Step length asymmetry adaptation response on the treadmill and transfer of learning to overground walking was assessed. Results. Step length asymmetry during the catch trial was the same between groups ( P = .195) confirming that both groups learned a similar amount. The magnitude of transfer to overground walking was greater in the Gradual than in the Abrupt group ( P = .041). Conclusions. The introduction of gradual perturbations (small errors), compared with abrupt (larger errors), during a locomotor adaptation task seems to improve transfer of the newly learned walking pattern to overground walking poststroke. However, given the limited magnitude of transfer, future studies should examine other factors that could impact locomotor learning and transfer poststroke.
    Type of Medium: Online Resource
    ISSN: 1545-9683 , 1552-6844
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2018
    detail.hit.zdb_id: 2100545-X
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  • 6
    In: The Journal of Physiology, Wiley, Vol. 596, No. 10 ( 2018-05-15), p. 1999-2016
    Abstract: Previous work demonstrated an effect of a single high‐intensity exercise bout coupled with motor practice on the retention of a newly acquired skilled arm movement, in both neurologically intact and impaired adults. In the present study, using behavioural and computational analyses we demonstrated that a single exercise bout, regardless of its intensity and timing, did not increase the retention of a novel locomotor task after stroke. Considering both present and previous work, we postulate that the benefits of exercise effect may depend on the type of motor learning (e.g. skill learning, sensorimotor adaptation) and/or task (e.g. arm accuracy‐tracking task, walking).
    Type of Medium: Online Resource
    ISSN: 0022-3751 , 1469-7793
    URL: Issue
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 1475290-6
    SSG: 12
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  • 7
    In: Journal of Visualized Experiments, MyJove Corporation, , No. 144 ( 2019-02-19)
    Type of Medium: Online Resource
    ISSN: 1940-087X
    Language: English
    Publisher: MyJove Corporation
    Publication Date: 2019
    detail.hit.zdb_id: 2259946-0
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  • 8
    In: PLOS ONE, Public Library of Science (PLoS), Vol. 18, No. 3 ( 2023-3-2), p. e0272114-
    Abstract: Relapsing-remitting Multiple Sclerosis is the most common demyelinating neurodegenerative disease and is characterized by periods of relapses and generation of various motor symptoms. These symptoms are associated with the corticospinal tract integrity, which is quantified by means of corticospinal plasticity which can be probed via transcranial magnetic stimulation and assessed with corticospinal excitability measures. Several factors, such as exercise and interlimb coordination, can influence corticospinal plasticity. Previous work in healthy and in chronic stroke survivors showed that the greatest improvement in corticospinal plasticity occurred during in-phase bilateral exercises of the upper limbs. During in-phase bilateral movement, both upper limbs are moving simultaneously, activating the same muscle groups and triggering the same brain region respectively. Altered corticospinal plasticity due to bilateral cortical lesions is common in MS, yet, the impact of these type of exercises in this cohort is unclear. The aim of this concurrent multiple baseline design study is to investigate the effects of in-phase bilateral exercises on corticospinal plasticity and on clinical measures using transcranial magnetic stimulation and standardized clinical assessment in five people with relapsing-remitting MS. The intervention protocol will last for 12 consecutive weeks (30–60 minutes /session x 3 sessions/week) and include in-phase bilateral movements of the upper limbs, adapted to different sports activities and to functional training. To define functional relation between the intervention and the results on corticospinal plasticity (central motor conduction time, resting motor threshold, motor evoked potential amplitude and latency) and on clinical measures (balance, gait, bilateral hand dexterity and strength, cognitive function), we will perform a visual analysis and if there is a potential sizeable effect, we will perform statistical analysis. A possible effect from our study, will introduce a proof-of-concept for this type of exercise that will be effective during disease progression. Trial registration: ClinicalTrials.gov NCT05367947 .
    Type of Medium: Online Resource
    ISSN: 1932-6203
    Language: English
    Publisher: Public Library of Science (PLoS)
    Publication Date: 2023
    detail.hit.zdb_id: 2267670-3
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  • 9
    In: Journal of Orthopaedic Research, Wiley, Vol. 36, No. 11 ( 2018-11), p. 2941-2948
    Abstract: Neuromuscular impairments, such as quadriceps weakness and activation deficits, persist after anterior cruciate ligament reconstruction (ACLR). Recent research demonstrating changes in the function of the primary motor cortex after ACLR posits that quadriceps impairments may be influenced by reduced corticospinal excitability. The purpose of this study was to investigate whether the integrity of the neuromotor axis of the vastus medialis is altered in subjects 2 weeks post‐ACLR compared to uninjured control subjects. Eighteen athletes 2 weeks post‐ACLR and 18 age and sex matched uninjured control subjects participated in this cross‐sectional study. We quantified corticospinal (resting motor threshold, RMT; motor evoked potential amplitudes at 120% RMT, MEP 120 ) and intracortical (inhibition and facilitation) excitability using single and paired pulse transcranial magnetic stimulation (TMS), respectively. We assessed spinal‐reflex excitability (H‐reflex amplitude normalized to maximal M‐wave, H/M ratio) using peripheral stimulation. Subjects post‐ACLR had higher RMTs ( p  = 0.001), greater MEP 120 amplitudes ( p  = 0.001), and more asymmetric facilitation ( p  = 0.041) than the uninjured control subjects. No significant group differences were found for intracortical inhibition ( p  = 0.289) and H/M ratio ( p  = 0.332). Our findings indicate that both intracortical and corticospinal excitability of vastus medialis are bilaterally altered in subjects 2 weeks after ACLR. Given persistent neuromuscular deficits seen after ACLR, rehabilitation strategies targeting intracortical and corticospinal deficits may potentially improve clinical outcomes. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2941–2948, 2018.
    Type of Medium: Online Resource
    ISSN: 0736-0266 , 1554-527X
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 2050452-4
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  • 10
    Online Resource
    Online Resource
    Frontiers Media SA ; 2022
    In:  Frontiers in Systems Neuroscience Vol. 16 ( 2022-10-28)
    In: Frontiers in Systems Neuroscience, Frontiers Media SA, Vol. 16 ( 2022-10-28)
    Abstract: Alpha and beta oscillations have been assessed thoroughly during walking due to their potential role as proxies of the corticoreticulospinal tract (CReST) and corticospinal tract (CST), respectively. Given that damage to a descending tract after stroke can cause walking deficits, detailed knowledge of how these oscillations mechanistically contribute to walking could be utilized in strategies for post-stroke locomotor recovery. In this review, the goal was to summarize, synthesize, and discuss the existing evidence on the potential differential role of these oscillations on the motor descending drive, the effect of transcranial alternate current stimulation (tACS) on neurotypical and post-stroke walking, and to discuss remaining gaps in knowledge, future directions, and methodological considerations. Electrophysiological studies of corticomuscular, intermuscular, and intramuscular coherence during walking clearly demonstrate that beta oscillations are predominantly present in the dorsiflexors during the swing phase and may be absent post-stroke. The role of alpha oscillations, however, has not been pinpointed as clearly. We concluded that both animal and human studies should focus on the electrophysiological characterization of alpha oscillations and their potential role to the CReST. Another approach in elucidating the role of these oscillations is to modulate them and then quantify the impact on walking behavior. This is possible through tACS, whose beneficial effect on walking behavior (including boosting of beta oscillations in intramuscular coherence) has been recently demonstrated in both neurotypical adults and stroke patients. However, these studies still do not allow for specific roles of alpha and beta oscillations to be delineated because the tACS frequency used was much lower (i.e., individualized calculated gait frequency was used). Thus, we identify a main gap in the literature, which is tACS studies actually stimulating at alpha and beta frequencies during walking. Overall, we conclude that for beta oscillations there is a clear connection to descending drive in the corticospinal tract. The precise relationship between alpha oscillations and CReST remains elusive due to the gaps in the literature identified here. However, better understanding the role of alpha (and beta) oscillations in the motor control of walking can be used to progress and develop rehabilitation strategies for promoting locomotor recovery.
    Type of Medium: Online Resource
    ISSN: 1662-5137
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2453005-0
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