Posts Tagged ischemic stroke

[ARTICLE] Prediction of Upper Limb Motor Recovery after Subacute Ischemic Stroke Using Diffusion Tensor Imaging: A Systematic Review and Meta-Analysis – Full Text

Abstract

Early evaluation of the pyramidal tract using Diffusion Tensor Imaging (DTI) is a prerequisite to decide the optimal treatment or to assess appropriate rehabilitation. The early predictive value of DTI for assessing motor and functional recovery in ischemic stroke (IS) has yielded contradictory results. The purpose is to systematically review and summarize the current available literature on the value of Fractional Anisotropy (FA) parameter of the DTI in predicting upper limb motor recovery after sub-acute IS. MEDLINE, PubMed, EMBASE, Google Scholar and Cochrane CENTRAL searches were conducted from January 1, 1950, to July 31, 2015, which was supplemented with relevant articles identified in the references. Correlation between FA and upper limb motor recovery measure was done. Heterogeneity was examined using Higgins I-squared, Tau-squared. Summary of correlation coefficient was determined using Random Effects model. Out of 166 citations, only eleven studies met the criteria for inclusion in the systematic review and six studies were included in the meta-analysis. A random effects model revealed that DTI parameter FA is a significant predictor for upper limb motor recovery after sub-acute IS [Correlation Coefficient=0.82; 95% Confidence Interval-0.66 to 0.90, P value<0.001]. Moderate heterogeneity was observed (Tau-squared=0.12, I-squared=62.14). The studies reported so far on correlation between DTI and upper limb motor recovery are few with small sample sizes. This meta-analysis suggests strong correlation between DTI parameter FA and upper limb motor recovery. Well-designed prospective trials embedded with larger sample size are required to establish these findings.

Introduction

Stroke is a major leading cause of death and disability worldwide especially in the elderly population [1]. Upper limb motor weakness is one of the most frequent complications after stroke with over 50% of stroke patients experiencing residual motor deficit [2]. Despite advances in treatment of acute ischemic stroke (IS) and post-stroke rehabilitation, the dependency rate after stroke still reaches 20%-30% [3]. Prognostication of upper limb motor outcomes after stroke is an important for specific rehabilitation strategies and final motor outcomes but, considered a difficult task. Many studies have tried to predict motor outcome in hemiparetic stroke patients using clinical findings [4,5], electrophysiological methods [6,7], and functional neuroimaging [8,9]. However, these studies have an inherent weakness that they were unable to visualize the corticospinal tract (CST), the most important structure for motor control, especially for fine motor control of the hand in humans [10].
Diffusion tensor imaging (DTI) is an advance non-invasive magnetic resonance imaging technique used to characterize the orientation properties of diffusion process of water molecules. DTI has a unique advantage in visualization and estimation of CST which is the most important neural tract for mainly upper limb motor function [11]. DTI permits the imaging of axonal pathways of the living brain and provides information about tissue microstructure by measuring fractional anisotropy (FA) [12]. FA is an index of the diffusion characteristics of water molecules preferentially directed along the axis of major axonal pathways. FA of the entire tract, acquired early after stroke, reflect acute and permanent damage to pyramidal tracts to determine clinical motor deficit and outcome. A tissue is considered to be fully isotropic when its FA is equal to 0, and fully anisotropic when its FA is equal to 1 [13].
Over the past two decades, numerous cross-sectional DTI studies have examined the relationships between age and the degree of anisotropy FA in white matter tracts [14]. Cross-sectional studies have demonstrated that older adults display lower FA values and higher mean diffusivity and radial diffusivity values compared with younger adults [15,16], with age correlations relatively weak during adulthood and stronger in senescence [17,18]. Currently, the most widely used invariant measure of anisotropy is FA described originally by Basser and Pierpaoli [12]. In the parametric data obtained from DTI, taking advantage of the much larger FA values of highly directional white matter structures, FA images are used to distinguish white matter and non-white matter tissues [19]. Studies that have examined small homogeneous samples of subcortical stroke patients have found that large asymmetries in FA are associated with poorer motor recovery [20,21]. Findings from recent studies have demonstrated the predictive value of DTI for motor outcome after stroke [22,23], however, it is not yet used routinely to make a prognosis but there have been some interesting recent developments in this area. Therefore, the purpose of this review is to establish the predictive value of DTI for upper limb motor recovery in IS patients.

Continue —> Prediction of Upper Limb Motor Recovery after Subacute Ischemic Stroke Using Diffusion Tensor Imaging: A Systematic Review and Meta-Analysis

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[Abstract] Mobile game-based virtual reality rehabilitation program for upper limb dysfunction after ischemic stroke.

Source: Mobile game-based virtual reality rehabilitation program for upper limb dysfunction after ischemic stroke – IOS Press

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[Abstract] Effect of Electroacupuncture Intervention on Rehabilitation of Upper Limb Motor Function in Patients with Ischemic Stroke. – PubMed – NCBI

Abstract

OBJECTIVE:

To observe the effect of electro-elongated needle intervention on rehabilitation of upper limb motor function in patients with ischemic stroke.

METHODS:

A total of 100 ischemic stroke patients were equally and randomly divided into manual acupuncture group and electro-elongated needle group (n=50 cases/group). For patients of the manual acupuncture group, filiform needles were respectively inserted into Jianyu (LI 15), Jiquan (HT 1), Shousanli (LI 10), Neiguan (PC 6) and Hegu (LI 4) on the affected side, manipulated with lifting-thrusting reinforcing or reducing method for 40 min, once daily for two weeks except the weekends, and for those of the electro-elongated needle group, elongated needles were repeatedly penetrated from LI 15 to Binao (LI 14), and from LI 10 to Waiguan (TE 5) on the affected side, followed by electrical stimulation for 40 min, once daily for two weeks except weekends. The therapeutic effect of manual acupuncture and electro-elongated needle for upper extremity rehabilitation was assessed according to the modified upper-extremity Fugl-Meyer Assessment (FMA) and Wolf Motor Function Test (WMFT) separately. The surface electromyogram (sEMG) of the deltoid muscle was recorded by using a Megawin Surface Electrogram System and the root mean square (RMS) of the amplitude of sEMG was used to evaluate the functional state of the deltoid muscle.

RESULTS:

After the treatment, the score of FMA and WMFT in both manual acupuncture and electro-elongated needle groups were significantly increased compared with pre-treatment in the same one group (P<0.01), suggesting an improvement of the motor function of the upper limbs, but RMS ratios of the amplitude of sEMG were evidently decreased in both groups (P<0.05, P<0.01), suggesting a relief of the abnormal muscular tension. The therapeutic effects of the electro-elongated needle were obviously superior to those of manual acupuncture in up-regulating FMA and WMFT scores and down-regulating RMS ratio (P<0.01).

CONCLUSION:

Electro-elongated needle therapy can effectively improve the motor function of upper limb in ischemic stroke patients and has a better effect in comparison with simple manual acupuncture.

Source: [Effect of Electroacupuncture Intervention on Rehabilitation of Upper Limb Motor Function in Patients with Ischemic Stroke]. – PubMed – NCBI

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[Abstract] Promoting recovery from ischemic stroke – Expert Review of Neurotherapeutics –

21 DEC 2015

Summary

Over recent decades, experimental and clinical stroke studies have identified a number of neurorestorative treatments that stimulate neural plasticity and promote functional recovery. In contrast to the acute stroke treatments thrombolysis and endovascular thrombectomy, neurorestorative treatments are still effective when initiated days after stroke onset, which makes them applicable to virtually all stroke patients. In this article, selected physical, pharmacological and cell-based neurorestorative therapies are discussed, with special emphasis on interventions that have already been transferred from the laboratory to the clinical setting. We explain molecular and structural processes that promote neural plasticity, discuss potential limitations of neurorestorative treatments, and offer a speculative viewpoint on how neurorestorative treatments will evolve.

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Source: Promoting recovery from ischemic stroke – Expert Review of Neurotherapeutics –

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[ARTICLE] Influence of Kinesitherapy on Gait in Patients with Ischemic Stroke in the Chronic Period – Full Text PDF

Abstract

AIM: The study aims to trace the influence of specialized kinesitherapeutic methodology (SKTM) on gait in patients with ischemic stroke in the chronic period (ISChP).

MATERIAL AND METHODS: The study was conducted with 56 patients with ISChP (duration of the disease up to 1 year). For determining changes in gait before and after the treatment a cadence of gait and maximum movement speed were taken into consideration. To determine the cadence, steps are counted for covering 6 meters and 10 meters respectively. The maximum speed of the gait is determined in m / min by dividing undergone distance (m) and time (min).

RESULTS: Patients were found to significantly normalize the parameters of gait. Compared to the initial data, there is a significant reduction in the number of steps on 6 and 10 meters and a tendency to increase the speed of gait, with the significant change during the 1st month with a level of significance of p <0.001.

CONCLUSION: The applied specialized kinesitherapeutic methodology continued later as exercise program at home, which significantly improved gait cadence and speed of movement in patients with ischemic stroke in the chronic period and is with a supportive prolonged exposure.

Full Text PDF

 

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[ARTICLE] Non-invasive electric current stimulation for restoration of vision after unilateral occipital stroke

Abstract

Occipital stroke often leads to visual field loss, for which no effective treatment exists. Little is known about the potential of non-invasive electric current stimulation to ameliorate visual functions in patients suffering from unilateral occipital stroke. One reason is the traditional thinking that visual field loss after brain lesions is permanent. Since evidence is available documenting vision restoration by means of vision training or non-invasive electric current stimulation future studies should also consider investigating recovery processes after visual cortical strokes. Here, protocols of repetitive transorbital alternating current stimulation (rtACS) and transcranial direct current stimulation (tDCS) are presented and the European consortium for restoration of vision (REVIS) is introduced. Within the consortium different stimulation approaches will be applied to patients with unilateral occipital strokes resulting in homonymous hemianopic visual field defects. One goal is to evaluate effects of the stimulation on vision parameters, vision-related quality of life, and physiological parameters that allow conclude about the mechanisms of vision restoration as induced by electrical current stimulation. These include EEG-spectra and coherence measures, and visual evoked potentials. The design of stimulation protocols involves an appropriate sham-stimulation condition and sufficient follow-up periods to test whether the effects are stable.

This is the first application of non-invasive current stimulation for vision rehabilitation in stroke-related visual field deficits. Positive results of the trials could have far-reaching implications for clinical practice. The ability of non-invasive electrical current brain stimulation to modulate the activity of neuronal networks may have implications for stroke rehabilitation also in the visual domain.

 

via Non-invasive electric current stimulation for restoration of vision after unilateral occipital stroke.

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[WEB SITE] New Computational Method Matches Brain Lesions to Impairments

Researchers at Weill Cornell Medical College have developed a new mathematical method that can predict the type and severity of impairment that a patient with brain damage will have given the location of their lesion.

With further development, this tool could not only allow clinicians to make more precise prognoses, but could also help them provide individual patients with personalized treatment plans, investigators say.

This so-called “glassbrain” visualizes the brain’s structural connectivity network and the effects on the network of a particular ischemic stroke lesion, plotted in green. Each sphere represents a different gray matter region, with blue indicating that the stroke had no effect on the gray matter region’s connectivity to the rest of the brain and red indicating that the stroke had some effect on the gray matter region’s connectivity to the rest of the brain. Pipes between the spheres indicate that a structural connection exists between the gray matter regions, with connections not affected by stroke drawn in black and those effected by the stroke in red. Image credit: Dr. Amy Kuceyski

Dr. Amy Kuceyeski, an assistant professor of mathematics in the Department of Radiology and at the Feil Family Brain and Mind Research Institute at Weill Cornell, pioneered this computational Network Modification (NeMo) Tool, which calculates how much damage a patient has sustained to their brain’s white matter, the tissue that connects different brain regions. When using this tool to evaluate patients with either multiple sclerosis (MS) or stroke, Dr. Kuceyeski and her team, who imported data into the NeMo tool that was derived solely from earlier MRI images of the brain, found that white matter damage can be used to predict physical and cognitive impairments a patient will experience. This research, which was published in two separate journals in November 2014 and February of this year, shows that using the NeMo tool could provide clinicians with an easy way to deliver more accurate prognoses and rehabilitation plans for their patients.

Continue –> Health News – New Computational Method Matches Brain Lesions to Impairments.

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