[Review] Neuroplasticity and functional recovery in rehabilitation after stroke – Full Text PDF

ABSTRACT

The concept of rehabilitation in stroke is currently based on evidence of neuroplasticity, considered to be responsible for recovery after a stroke. The scarcity of information in the literature, especially concerning methods that specifically evaluate neuroplasticity, does not match its functional importance. In general, the literature discusses the functional evaluations of limbs after a stroke and a few studies focus on cerebral impairment.

Objective: To review the literature and evaluate current rehabilitation programs for stroke and their potential to promote functional improvement and neuronal plasticity.

Method: A literature review was conducted searching the PubMed database with articles published from 2000 to 2015. The descriptors used were: “Stroke/ rehabilitation” OR “Stroke/therapy” AND “Neuronal Plasticity”.

Results: From the 86 studies found, 36 were classified as Therapy/Narrow, with 17 articles being excluded either for not meeting the inclusion criteria or for not presenting a theme relevant to the study. After the selection by title and abstract, 19 articles were read entirely. Of those, six were excluded for not addressing the objective of the present study. In all, 13 articles were reviewed. The evaluation instruments in those 13 articles varied between functional magnetic resonance, transcranial magnetic stimulation, and single photon emission computed tomography (SPECT). The interventions used were specific for the upper limbs, except for one article about an intervention through hyperbaric oxygen therapy.

Conclusion: Few studies evaluated the neuronal plasticity in rehabilitation after a stroke, and most articles presented improvements in function as well as in neuroplasticity. However, larger studies should investigate and correlate both aspects in the rehabilitation of stroke patients.

Full Text PDF

[Abstract] Sensorimotor modulation by botulinum toxin A in post-stroke arm spasticity: Passive hand movement – Journal of the Neurological Sciences

Highlights

• •Patients with upper limb post-stroke spasticity were treated with botulinum toxin.
• •Central effects of spasticity treatment were studied using functional MRI.
• •Brain activation pattern was assessed during passive hand movements.
• •BoNT-induced spasticity relief is associated with changes in sensorimotor network.

Abstract

Introduction

In post-stroke spasticity, functional imaging may uncover modulation in the central sensorimotor networks associated with botulinum toxin type A (BoNT) therapy. Investigations were performed to localize brain activation changes in stroke patients treated with BoNT for upper limb spasticity using functional magnetic resonance imaging (fMRI).

Methods

Seven ischemic stroke patients (4 females; mean age 58.86) with severe hand paralysis and notable spasticity were studied. Spasticity was scored according to the modified Ashworth scale (MAS). fMRI examination was performed 3 times: before (W0) and 4 (W4) and 11 weeks (W11) after BoNT. The whole-brain fMRI data were acquired during paced repetitive passive movements of the plegic hand (flexion/extension at the wrist) alternating with rest. Voxel-by-voxel statistical analysis using the General Linear Model (GLM) implemented in FSL (v6.00)/FEAT yielded group session-wise statistical maps and paired between-session contrasts, thresholded at the corrected cluster-wise significance level of p < 0.05.

Results

As expected, BoNT transiently lowered MAS scores at W4. Across all the sessions, fMRI activation of the ipsilesional sensorimotor cortex (M1, S1, and SMA) dominated. At W4, additional clusters transiently emerged bilaterally in the cerebellum, in the contralesional sensorimotor cortex, and in the contralesional occipital cortex. Paired contrasts demonstrated significant differences W4 > W0 (bilateral cerebellum and contralesional occipital cortex) and W4 > W11 (ipsilesional cerebellum and SMA). The remaining paired contrast (W0 > W11) showed activation decreases mainly in the ipsilesional sensorimotor cortex (M1, S1, and SMA).

Conclusions

The present study confirms the feasibility of using passive hand movements to map the cerebral sensorimotor networks in patients with post-stroke arm spasticity and demonstrates that BoNT-induced spasticity relief is associated with changes in task-induced central sensorimotor activation, likely mediated by an altered afferent drive from the spasticity-affected muscles.

Source: Sensorimotor modulation by botulinum toxin A in post-stroke arm spasticity: Passive hand movement – Journal of the Neurological Sciences

[ARTICLE] A Randomized Controlled Trial of the Effect of Early Upper-Limb Training on Stroke Recovery and Brain Activation – Full Text

Abstract

Background: Upper-limb (UL) dysfunction is experienced by up to 75% of patients poststroke. The greatest potential for functional improvement is in the first month. Following reperfusion, evidence indicates that neuroplasticity is the mechanism that supports this recovery.

Objective: This preliminary study hypothesized increased activation of putative motor areas in those receiving intensive, task-specific UL training in the first month poststroke compared with those receiving standard care.

Methods: This was a single-blinded, longitudinal, randomized controlled trial in adult patients with an acute, first-ever ischemic stroke; 23 participants were randomized to standard care (n = 12) or an additional 30 hours of task-specific UL training in the first month poststroke beginning week 1. Patients were assessed at 1 week, 1 month, and 3 months poststroke. The primary outcome was change in brain activation as measured by functional magnetic resonance imaging.

Results: When compared with the standard-care group, the intensive-training group had increased brain activation in the anterior cingulate and ipsilesional supplementary motor areas and a greater reduction in the extent of activation (P = .02) in the contralesional cerebellum. Intensive training was associated with a smaller deviation from mean recovery at 1 month (Pr>F0 = 0.017) and 3 months (Pr>F = 0.006), indicating more consistent and predictable improvement in motor outcomes.

Conclusion: Early, more-intensive, UL training was associated with greater changes in activation in putative motor (supplementary motor area and cerebellum) and attention (anterior cingulate) regions, providing support for the role of these regions and functions in early recovery poststroke.

Full Text HTML

Source: A Randomized Controlled Trial of the Effect of Early Upper-Limb Training on Stroke Recovery and Brain Activation

[SPECIAL REPORT] Brain Plasticity and Stroke Rehabilitation – Full Text HTML

Abstract

Neuronal connections and cortical maps are continuously remodeled by our experience. Knowledge of the potential capabilityof the brain to compensate for lesions is a prerequisite for optimal stroke rehabilitation strategies.

Experimental focal cortical lesions induce changes in adjacent cortex and in the contralateral hemisphere. Neuroimaging studies in stroke patients indicate altered poststroke activation patterns, which suggest some functional reorganization. To what extent functional imaging data correspond to outcome data needs to be evaluated. Reorganization may be the principle process responsible for recovery of function after stroke, but what are the limits, and to what extent can postischemic intervention facilitate such changes?

Postoperative housing of animals in an enriched environment can significantly enhance functional outcome and can also interact with other interventions, including neocortical grafting. What role will neuronal progenitor cells play in future rehabilitation—stimulated in situ or as neural replacement? And what is the future for blocking neural growth inhibitory factors?

Better knowledge of postischemic molecular and neurophysiological events, and close interaction between basic and applied research, will hopefully enable us to design rehabilitation strategies based on neurobiological principles in a not-too-distant future.

Continue —>  Brain Plasticity and Stroke Rehabilitation.