Stroke: a global response is needed

Estimating morbidity due to stroke in Nigeria: a systematic review and meta-analysis

BACKGROUND

The response to stroke in Nigeria is impaired by inadequate epidemiologic information. We sought to collate available evidence and estimate the incidence of stroke and prevalence of stroke survivors in Nigeria.

METHODS

Using random effects meta-analysis, we pooled nationwide and regional incidence and prevalence of stroke from the estimates reported in each study.

RESULTS

Eleven studies met our selection criteria. The pooled crude incidence of stroke in Nigeria was 26.0 (12.8-39.0) /100,000 person-years, with this higher among men at 34.1 (9.7-58.4) /100,000, compared to women at 21.2 (7.4-35.0) /100,000. The pooled crude prevalence of stroke survivors in Nigeria was 6.7 (5.8-7.7) /1000 population, with this also higher among men at 6.4 (5.1-7.6) /1000, compared to women at 4.4 (3.4-5.5) /1000. In the period 2000-2009, the incidence of stroke in Nigeria was 24.3 (95% CI: 11.9-36.8) per 100,000, with this increasing to 27.4 (95% CI: 2.2-52.7) per 100,000 from 2010 upwards. The prevalence of stroke survivors increased minimally from 6.0 (95% CI: 4.6-7.5) per 1000 to 7.5 (95% CI: 5.8-9.1) per 1000 over the same period. The prevalence of stroke survivors was highest in the South-south region at 13.4 (9.1-17.8) /100,000 and among rural dwellers at 10.8 (7.5-14.1) /100,000.

CONCLUSION

Although study period does not appear to contribute substantially to variations in stroke morbidity in Nigeria, an increasing number of new cases compared to survivors may be due in part to limited door-door surveys, or possibly reflects an increasing mortality from stroke in the country.

UPLC-QTOF/MS-Based Metabolomics Reveals the Protective Mechanism of Hydrogen on Mice with Ischemic Stroke

As a reductive gas, hydrogen plays an antioxidant role by selectively scavenging oxygen free radicals. It has been reported that hydrogen has protective effects against nerve damage caused by ischemia-reperfusion in stroke, but the specific mechanism is still unclear. Therefore, this study aims to investigate the protective effects of hydrogen on stroke-induced ischemia-reperfusion injury and its detailed mechanism. Two weeks after the inhalation of high concentrations (66.7%) of hydrogen, middle cerebral artery occlusion (MCAO) was induced in mice using the thread occlusion technique to establish an animal model of the focal cerebral ischemia-reperfusion. Then, a metabolomics analysis of mouse cerebral cortex tissues was first performed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) to study the metabolic changes and protective mechanisms of hydrogen on stroke ischemia-reperfusion injury. According to the metabolomic profiling of cortex tissues, 29 different endogenous metabolites were screened, including palmitoyl-L-carnitine, citric acid, glutathione, taurine, acetyl-L-carnitine, N-acetylaspartylglutamic acid (NAAG), L-aspartic acid, lysophosphatidylcholine (LysoPC) and lysophosphatidylethanolamine (LysoPE). Through pathway analysis, the metabolic pathways were concentrate on the glutathione pathway and the taurine pathway, mitochondrial energy metabolism and phospholipid metabolism that related to the oxidative stress process. This result reveals that hydrogen may protect against ischemic stroke by reducing oxidative stress during ischemia-reperfusion, thereby protecting nerve cells from reactive oxygen species(ROS).

Experiences of venue based exercise interventions for people with stroke in the UK: a systematic review and thematic synthesis of qualitative research

BACKGROUND

The physical benefits of exercise following stroke are research evidenced and the UK stroke population is increasingly encouraged to engage with exercise interventions. A synthesis of qualitative research is required to further understand the perceived experience and psychosocial effect of exercise for people with stroke.

OBJECTIVES

To provide a systematic search and synthesis of evidence about the experiences and reported impact of participation in venue based exercise following stroke in the UK.

DATA SOURCES

Eligible studies were identified through a rigorous search of Medline, Cinahl, AMED, PsycINFO, SportDiscus, Proquest and ETHOS from January 2000 until December 2017.

STUDY ELIGIBILITY CRITERIA

Full text qualitative studies or service evaluations conducted in the UK which explored the reported experience of venue based exercise amongst people with stroke.

STUDY SYNTHESIS AND APPRAISAL

Included studies were evaluated through application of the Consolidated Criteria for Reporting Qualitative Research. Data synthesis using a thematic approach generated descriptive and analytical themes.

RESULTS

Six research studies and one service evaluation met the inclusion criteria; methodological quality was variable. These studies highlighted that people with stroke gain confidence and renewed identity through exercise participation. Perceived improvements in physical function were reported and participants enjoyed stroke specific exercise programmes in de-medicalised venues.

LIMITATIONS

The studies only accessed people who had completed the exercise programmes; non-completers were not represented.

CONCLUSION

Venue based exercise programmes have a positive effect on perceived wellbeing following stroke. Further research into the reasons for discontinuation of exercise participation following stroke is required. Systematic Review Registration Number PROSPERO 2017:CRD42017072483.

Paroxysmal supraventricular tachycardia and risk of ischemic stroke: A systematic review and meta-analysis

BACKGROUND

Paroxysmal supraventricular tachycardia (PSVT) has been traditionally considered as a benign rhythm disorder. However, recent studies have suggested that patients with PSVT may have a higher risk of ischemic stroke although the data are limited and inconclusive. The current systematic review and meta-analysis was conducted with the aims to identify all available studies and summarize their results together to better characterize the risk of ischemic stroke among patients with PSVT.

METHODS

A comprehensive literature review was conducted by searching for published articles indexed in MEDLINE and EMBASE databases from inception through November 11, 2018 to identify all observational studies that compared the risk of ischemic stroke between patients with PSVT and individuals without PSVT. Pooled risk ratio (RR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method of DerSimonian and Laird.

RESULTS

A total 5 studies (4 cohort studies and 1 case-control study) with 4 886 977 participants met the eligibility criteria and were included into the meta-analysis. The risk of ischemic stroke among patients with PSVT was significantly higher than individuals without PSVT with the pooled RR of 2.03 (95% CI, 1.22-3.38, I 2 = 89%).

CONCLUSION

This study found that PSVT is associated with a higher risk of ischemic stroke. Whether this association is causal and how it should be addressed in clinical practice require further investigations.

The Role of Mast Cells in Stroke

Mast cells (MCs) are densely granulated perivascular resident cells of hematopoietic origin. Through the release of preformed mediators stored in their granules and newly synthesized molecules, they are able to initiate, modulate, and prolong the immune response upon activation. Their presence in the central nervous system (CNS) has been documented for more than a century. Over the years, MCs have been associated with various neuroinflammatory conditions of CNS, including stroke. They can exacerbate CNS damage in models of ischemic and hemorrhagic stroke by amplifying the inflammatory responses and promoting brain–blood barrier disruption, brain edema, extravasation, and hemorrhage. Here, we review the role of these peculiar cells in the pathophysiology of stroke, in both immature and adult brain. Further, we discuss the role of MCs as potential targets for the treatment of stroke and the compounds potentially active as MCs modulators.

Post-stroke inflammation-target or tool for therapy?

Inflammation is currently considered a prime target for the development of new stroke therapies. In the acute phase of ischemic stroke, microglia are activated and then circulating immune cells invade the peri-infarct and infarct core. Resident and infiltrating cells together orchestrate the post-stroke inflammatory response, communicating with each other and the ischemic neurons, through soluble and membrane-bound signaling molecules, including cytokines. Inflammation can be both detrimental and beneficial at particular stages after a stroke. While it can contribute to expansion of the infarct, it is also responsible for infarct resolution, and influences remodeling and repair. Several pre-clinical and clinical proof-of-concept studies have suggested the effectiveness of pharmacological interventions that target inflammation post-stroke. Experimental evidence shows that targeting certain inflammatory cytokines, such as tumor necrosis factor, interleukin (IL)-1, IL-6, and IL-10, holds promise. However, as these cytokines possess non-redundant protective and immunoregulatory functions, their neutralization or augmentation carries a risk of unwanted side effects, and clinical translation is, therefore, challenging. This review summarizes the cell biology of the post-stroke inflammatory response and discusses pharmacological interventions targeting inflammation in the acute phase after a stroke that may be used alone or in combination with recanalization therapies. Development of next-generation immune therapies should ideally aim at selectively neutralizing pathogenic immune signaling, enhancing tissue preservation, promoting neurological recovery and leaving normal function intact.

Investigation of the emotional network in depression after stroke: A study of multivariate Granger causality analysis of fMRI data

OBJECTIVE

Depression after stroke (DAS) is a serious complication of stroke that significantly restricts rehabilitation. Brain imaging technology is an important method for studying the emotional network of DAS. However, few studies have focused on dynamic interactions within the network. The aim of this study was to investigate the emotional network of frontal lobe DAS using the multivariate Granger causality analysis (GCA) method, a technique that can estimate the association among the brain areas to analyze functional magnetic resonance imaging (fMRI) data collected from DAS and no depression after stroke (NDAS).

METHOD

Thirty-six first-time ischemic right frontal lobe stroke patients underwent resting-state fMRI (rs-fMRI) scans. The clinical assessment scale used for screening subjects was as follows: the 24-item Hamilton Rating Scale for Depression (HAMD-24), the National Institutes of Health Stroke Scale (NIHSS), the Mini-Mental State Examination (MMSE), and the Barthel Index (BI). The multivariate GCA method was used to analyze fMRI data collected from DAS and NDAS.

RESULTS

The results showed positive regulations in the order from the ventromedial prefrontal cortex (VMPFC), the anterior cingulate cortex (ACC), and the amygdala (AMYG) to the thalamus, and when the interaction order is opposite, the moderating effect is negative. The thalamus could predict the negative activity of the insular (IC) via the ACC. The dorsolateral prefrontal cortex (DLPFC) could predict the activity of the ACC via the temporal pole (TP).

CONCLUSION

This study found a VMPFC-ACC-AMYG-thalamus emotional circuit to explain the network between different brain regions associated with DAS. The DLPFC and TP play an important role in the emotional regulation of DAS, and the function of the IC is regulated negatively by the thalamus. These findings advance the neural theory of DAS, which is based on the functional relationship between different brain areas.

Acute and Post-acute Neuromodulation Induces Stroke Recovery by Promoting Survival Signaling, Neurogenesis, and Pyramidal Tract Plasticity

Repetitive transcranial magnetic stimulation (rTMS) has gained interest as a non-invasive treatment for stroke based on the data promoting its effects on functional recovery. However, the exact action mechanisms by which the rTMS exert beneficial effects in cellular and molecular aspect are largely unknown. To elucidate the effects of high- and low-frequency rTMS in the acute-ischemic brain, we examined how rTMS influences injury development, cerebral blood flow (CBF), DNA fragmentation, neuronal survival, pro- and anti-apoptotic protein activations after 30 and 90 min of focal cerebral ischemia. In addition, inflammation, angiogenesis, growth factors and axonal outgrowth related gene expressions, were analyzed. Furthermore, we have investigated the effects of rTMS on post-acute ischemic brain, particularly on spontaneous locomotor activity, perilesional tissue remodeling, axonal sprouting of corticobulbar tracts, glial scar formation and cell proliferation, in which rTMS was applied starting 3 days after the stroke onset for 28 days. In the high-frequency rTMS received animals reduced DNA fragmentation, infarct volume and improved CBF were observed, which were associated with increased Bcl-xL activity and reduced Bax, caspase-1, and caspase-3 activations. Moreover, increased angiogenesis, growth factors; and reduced inflammation and axonal sprouting related gene expressions were observed. These results correlated with reduced microglial activation, neuronal degeneration, glial scar formation and improved functional recovery, tissue remodeling, contralesional pyramidal tract plasticity and neurogenesis in the subacute rTMS treated animals. Overall, we propose that high-frequency rTMS in stroke patients can be used to promote functional recovery by inducing the endogenous repair and recovery mechanisms of the brain.

Effects of transcranial direct current stimulation on the rehabilitation of painful shoulder following a stroke: protocol for a randomized, controlled, double-blind, clinical trial

Background

Shoulder pain is reported to be one of the major challenges faced in the functional recovery of patients in rehabilitation following a stroke. In such cases, transcranial direct current stimulation (tDCS) has been used as an additional therapeutic tool for improvements in central and peripheral pain. The aim of the proposed study is to evaluate the effect of tDCS when combined with upper limb physical therapy on pain intensity and functional improvement in stroke survivors with shoulder pain in the hemiplegic limb.

Methods

A randomized, placebo-controlled, double-blind, clinical trial is proposed. The volunteers will be randomly allocated to receive passive movement on the upper limb, which will be performed by the therapist for 20 min followed by either active tDCS or sham tDCS (current stimulation for 30 s) during simultaneous physical activity of the upper limb (“mini-bike”) for 20 min, totaling 40 min of intervention performed in 10 consecutive sessions. The anode electrode will be positioned over the primary motor cortex with a current of 2 mA and the cathode electrode will be positioned in the supraorbital region contralateral to the anode. The primary outcome will be shoulder pain intensity, which will be measured using the visual analog scale (VAS) on three occasions: 1) pre-intervention; 2) after 10 interventions (5 weekly sessions, for 2 weeks); and 3) 30 days after the end of the interventions. The secondary outcomes will be motor performance, upper limb function, and quality of life.

Trial registration

Brazilian Registry of Clinical Trials, RBR-8F5MNY. Registered on June 2, 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3266-y) contains supplementary material, which is available to authorized users.

Seasonal variation in the occurrence of ischemic stroke: A meta-analysis

Stroke was demonstrated to correlate with seasonal variation. However, the relevant studies were incongruous. To better understand the rules of seasonal impact on ischemic stroke (IS) patients, we performed this meta-analysis. We systematically searched relevant observational studies in Pubmed, Web of science and Embase from January 1, 1980, to November 1, 2017, in English. Patients included in this study were adults who suffered from IS. Stata version 12.0 software was used to pool useful data and calculate incidence rate ratios (IRRs) and their 95% confidence intervals (CIs). We also performed heterogeneity and sensitivity analyses and evaluated publication bias. Thirty-three observational studies involving 234,196 participants were incorporated into the meta-analysis. Summer and December were regarded as reference, respectively. The IRRs were calculated showing: IRR_Winter 1.05 (95% CI 1.04-1.07), IRR_Autumn 1.03 (95% CI 1.02-1.04), IRR_Spring 1.02 (95% CI 1.01-1.03). No obvious difference existed among 12 months. Stratified analyses on Köppen classification were also conducted. Between-study heterogeneity was discovered; however, predefined stratified analyses and meta-regression could not reduce this heterogeneity. Our meta-analysis has revealed very little seasonal variation in the overall study. Both cold and hot months may be high risky for IS after stratified by Köppen Climate Classification. Thus, a rationale to environmental setting of risky patient management could be provided. More studies with specific assessments are warranted for further comprehensive investigation.

Anthology of stroke epidemiology in the 20th and 21st centuries: Assessing the past, the present, and envisioning the future

This narrative overview of stroke epidemiology shows dramatic changes in stroke incidence, prevalence, mortality, disability, and the understanding of risk factors and primary stroke prevention strategies over the last few decades. Likely future directions of stroke epidemiology and prevention are outlined.

Translation and Cross-Cultural Adaptation of SATIS-Stroke for Use in Brazil: A Satisfaction Measure of Activities and Participation in Stroke Survivors

Introduction

SATIS-Stroke was developed to measure satisfaction regarding activities and participation among stroke survivors based on the concepts contained in the International Classification of Functioning, Disability, and Health. However, this measure is only available in English and French.

Objective

Perform the translation and cross-cultural adaptation of SATIS-Stroke to Brazilian Portuguese and test the preliminary reliability of this measure.

Methods

The translation process followed standardized guidelines and consisted of six phases: initial translation, back-translation, analysis of expert committee, test of final version, submission, and assessment of all written reports. To test the preliminary test-retest reliability, the measure was administered by a single observer on two occasions with an interval of 7 to 14 days for the determination of intraobserver agreement and administered again by a second observer for the determination of interobserver agreement. Reliability was analyzed using the intraclass correlation coefficient (ICC_2,1) and respective 95% confidence intervals (CI).

Results

All stages of the cross-cultural adaptation process were respected and the final translated version of SATIS-Stroke exhibited semantic, idiomatic, cultural, and conceptual equivalence to the original version. The preliminary analysis revealed excellent intraobserver and interobserver reliability (ICC = 0.93; 95% CI: 0.83-0.97, p = 0.001 and ICC = 0.90; 95% CI: 0.74-0.96; p = 0.001, respectively). The items demonstrated adequate internal consistency, although ceiling and floor effects were considered beyond acceptable standards for some items. In the exploratory factor analysis, three factors were extracted that aggregated more than one construct to each component, but all were related to the “Activities and Participation” component of the International Classification of Functioning, Disability, and Health.

Conclusion

The final version of the SATIS-Stroke scale in Brazilian Portuguese proved to be adequate and reliable for use on the Brazilian population. Further studies are underway to give continuity to the validation process and analyze the others measurement properties of the scale in the Brazilian population.

Brain-gut axis after stroke

Stroke leads to inflammatory and immune response in the brain and immune organs. The gut or gastrointestinal tract is a major immune organ equipped with the largest pool of immune cells representing more than 70% of the entire immune system and the largest population of macrophages in the human body. The bidirectional communication between the brain and the gut is commonly known as brain–gut or gut–brain axis. Stroke often leads to gut dysmotility, gut microbiota dysbiosis, “leaky” gut, gut hemorrhage, and even gut-origin sepsis, which is often associated with poor prognosis. Emerging evidence suggests that gut inflammatory and immune response plays a key role in the pathophysiology of stroke and may become a key therapeutic target for its treatment. Ischemic brain tissue produces damage-associated molecular patterns to initiate innate and adaptive immune response both locally and systemically through the specialized pattern-recognition receptors (e.g., toll-like receptors). After stroke, innate immune cells including neutrophils, microglia or macrophages, mast cells, innate lymphocytes (IL-17 secreting γδ T-cell), and natural killer T-cell respond within hours, followed by the adaptive immune response through activation of T and B lymphocytes. Subpopulations of T-cells can help or worsen ischemic brain injury. Pro-inflammatory Th1, Th17, and γδ T-cells are often associated with increased inflammatory damage, whereas regulatory T-cells are known to suppress postischemic inflammation by increasing the secretion of anti-inflammatory cytokine IL-10. Although known to play a key role, research in the gut inflammatory and immune response after stroke is still in its initial stage. A better understanding of the gut inflammatory and immune response after stroke may be important for the development of effective stroke therapies. The present review will discuss recent advances in the studies of the brain–gut axis after stroke, the key issues to be solved, and the future directions.

Stroke in HIV

Stroke is a heterogeneous disease in persons living with human immunodeficiency virus (HIV). HIV is thought to increase the risk of stroke through both HIV-related and traditional stroke risk factors, which vary with respect to the patient's age and clinical characteristics. Numerous studies show that detectable viremia and immunosuppression increase the risk of stroke across all ages, whereas traditional risk factors are more common in the aging population with HIV. As persons living with HIV age and acquire traditional stroke risk factors, the prevalence of stroke will likely continue to increase. Large- and small-vessel disease are the most common causes of stroke, although it is important to evaluate for infectious etiology as well. Research regarding the management of stroke in patients with HIV is scant, and recommendations often parallel those for the general population. Treatment of HIV and effective reduction of traditional stroke risk factors is important to reduce the risk of stroke in persons living with HIV. Future research will help elucidate the pathophysiology of HIV and stroke risk, investigate sex differences in stroke risk, and evaluate the safety and benefits of standard stroke preventative measures and HIV-specific interventions in this population.

Stroke in the Arab World: A bibliometric analysis of research activity (2002-2016)

Background

The Arab world has an increasing prevalence of strokes, a leading cause of death in this part of the world.

Aims

The aim of this article is to quantify the stroke research activity in the Arab countries over the past 15 years taking into consideration the population, GDP, and DALY of each country.

Methods

A PubMed search was conducted to find stroke research articles published from the Arab countries between 2002 and 2016 (inclusive). Medical subject headings related to strokes and author origin/affiliation were used for this purpose.

Results

The Arab world only produced 0.51% of all the stroke-related publications on PubMed even though the stroke-related DALY percentage in this region was greater than 2.88% during the period we studied. In general, the number of publications increased in the last few years. Somalia came first regarding the percentage of stroke to non-stroke publications released. Lebanon had the highest number of publications per GDP (in US Billion Dollars), Qatar had the highest number of publications per million persons (PPMP), while Saudi Arabia had the highest number of publications per 1% of stroke DALY. In addition, a strong positive correlation was found between the number of stroke publications and GDP; however, the correlation between the number of stroke publication and either population size or DALY was a weak positive one.

Conclusions

A general increase in publications is noticed, but stroke research activity in the Arab world is still poor compared to other parts of the world.

•

The Arab world only contributed to 0.51% of all the stroke-related publications on PubMed even though the stroke-related DALY percentage in this region was greater than 2.88% between 2002 and 2016.

•

The number of stroke-related publications produced by the Arab world increased in the last few years.

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Lebanon had the highest number of publications per GDP (in US Billion Dollars), Qatar had the highest number of publications per million persons (PPMP).

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A strong positive correlation was found between the number of stroke publications and GDP.

Intra-carotid arterial transfusion of autologous circulatory derived CD34+ cells for old ischemic stroke patients - a phase I clinical trial to evaluate safety and tolerability

This phase I clinical trial tested the hypothesis that circulatory CD34+ cell therapy might be safe for old ischemic stroke (IS) (defined as IS>6 months) patients and also to evaluate the neurological function after the therapy. Nine old IS patients (with mean IS interval: 8.6 ± 6.4 years) were consecutively enrolled and received intra-carotid artery transfusion of circulatory-derived autologous CD34+ cells (3.0×10⁷ cells/patient) into the ipsilateral brain infarct area at catheterization room by Catheter Looping Technique, after subcutaneous G-CSF injection (5 μg/kg twice a day for 4 days). The results showed that procedural safety was 100% with all patients uneventfully discharged. The circulating number of EPCs and angiogenesis (i.e., by Matrigel assay) were significantly higher at post than at prior to G-CSF treatment (all P<0.001). Time courses (0/5/10/30 minutes) of blood samplings from right-internal jugular vein exhibited significantly increased in levels of SDF-1α and EPCs numbers in time points of 5/10/30 minutes than in the baseline (0 minute) (all P<0.05). Barthel index was increased (defined as ≥5 scores) in 44.4% (4/9) and CASI score was notably improved (all P<0.01) at 6-month follow-up after the cell therapy as compared to the baseline. No recurrent IS or any tumorigenesis was found in these patients with a mean follow-up time interval of 16.5 ± 6.2 months. All of these patients remain survive and are followed up at outpatient department. In conclusion, CD34+ cell therapy is safe and might offer some benefit to old IS patients.

Involvement of polymorphisms of the nerve growth factor and its receptor encoding genes in the etiopathogenesis of ischemic stroke

Background

Despite the important role of the nerve growth factor in the survival and maintenance of neurons in ischemic stroke, data regarding the relationships between variations in the encoding gene and stroke are lacking. In the present study, we evaluated the association of the functional polymorphisms in NGF (rs6330) and NGFR (rs2072446 and rs734194) genes with ischemic stroke in an Armenian population.

Methods

In total, 370 unrelated individuals of Armenian nationality were enrolled in this study. Genomic DNA samples of patients and healthy controls were genotyped using polymerase chain reaction with sequence-specific primers.

Results

The results obtained indicate that the minor allele of rs6330 (P_corr = 2.4E-10) and rs2072446 (P_corr = 0.02) are significantly overrepresented in stroke group, while the minor allele of rs734194 (P_corr = 8.5E-10) was underrepresented in diseased subjects. Single nucleotide polymorphisms in NGF gene (rs6330) and NGFR gene (rs2072446 and rs734194) are associated with the disease. Furthermore, it was shown that the carriage of the NGF rs6330*T minor allele is associated with increased infarct volume and higher risk of recurrent stroke.

Conclusions

In conclusion, our findings suggest that the NGF rs6330*T and NGFR rs2072446*T minor alleles might be nominated as a risk factor for developing ischemic stroke and NGFR rs734194*G minor allele as a protective against this disease at least in Armenian population.

Hierarchical Compliance Control of a Soft Ankle Rehabilitation Robot Actuated by Pneumatic Muscles

Traditional compliance control of a rehabilitation robot is implemented in task space by using impedance or admittance control algorithms. The soft robot actuated by pneumatic muscle actuators (PMAs) is becoming prominent for patients as it enables the compliance being adjusted in each active link, which, however, has not been reported in the literature. This paper proposes a new compliance control method of a soft ankle rehabilitation robot that is driven by four PMAs configured in parallel to enable three degrees of freedom movement of the ankle joint. A new hierarchical compliance control structure, including a low-level compliance adjustment controller in joint space and a high-level admittance controller in task space, is designed. An adaptive compliance control paradigm is further developed by taking into account patient’s active contribution and movement ability during a previous period of time, in order to provide robot assistance only when it is necessarily required. Experiments on healthy and impaired human subjects were conducted to verify the adaptive hierarchical compliance control scheme. The results show that the robot hierarchical compliance can be online adjusted according to the participant’s assessment. The robot reduces its assistance output when participants contribute more and vice versa, thus providing a potentially feasible solution to the patient-in-loop cooperative training strategy.

Influence of pilates training on the quality of life of chronic stroke patients

[Purpose] This study was to observe the influence of Pilates training on the quality of life in chronic stoke patients. [Subjects and Methods] Forty chronic stroke patients participated in this study. They were divided into same number of experimental group (EG) and control group (CG). EG participated in a 60-min Pilates training program, twice a week for 12 weeks, while the CG did not participate in any exercise-related activities for the duration and participating in general occupational therapy without any exercise-related activities. Then the MMSE-K was performed before and after Pilates training to observe the influence of Pilates training on the quality of life in chronic stroke patients. [Results] Statistically significant improvement in the physical, social, and psychological domains was found in EG after the training. No statistically significant difference was found in all three quality of life domains for the CG. EG experienced a statistically significant improvement in all quality of life domains compared with that of CG. [Conclusion] Therefore, participation in Pilates training was found to effectively improve the quality of life in stroke patients. Pilates training involves low and intermediate intensity resistance and repetition that match the patient’s physical ability and can be a remedial exercise program that can improve physical ability and influence quality of life.

Advancing stroke genomic research in the age of Trans-Omics big data science: Emerging priorities and opportunities

BACKGROUND

We systematically reviewed the genetic variants associated with stroke in genome-wide association studies (GWAS) and examined the emerging priorities and opportunities for rapidly advancing stroke research in the era of Trans-Omics science.

METHODS

Using the PRISMA guideline, we searched PubMed and NHGRI- EBI GWAS catalog for stroke studies from 2007 till May 2017.

RESULTS

We included 31 studies. The major challenge is that the few validated variants could not account for the full genetic risk of stroke and have not been translated for clinical use. None of the studies included continental Africans. Genomic study of stroke among Africans presents a unique opportunity for the discovery, validation, functional annotation, Trans-Omics study and translation of genomic determinants of stroke with implications for global populations. This is because all humans originated from Africa, a continent with a unique genomic architecture and a distinctive epidemiology of stroke; as well as substantially higher heritability and resolution of fine mapping of stroke genes.

CONCLUSION

Understanding the genomic determinants of stroke and the corresponding molecular mechanisms will revolutionize the development of a new set of precise biomarkers for stroke prediction, diagnosis and prognostic estimates as well as personalized interventions for reducing the global burden of stroke.

Model-based cap thickness and peak cap stress prediction for carotid MRI

A rupture-prone carotid plaque can potentially be identified by calculating the peak cap stress (PCS). For these calculations, plaque geometry from MRI is often used. Unfortunately, MRI is hampered by a low resolution, leading to an overestimation of cap thickness and an underestimation of PCS. We developed a model to reconstruct the cap based on plaque geometry to better predict cap thickness and PCS. We used histological stained plaques from 34 patients. These plaques were segmented and served as the ground truth. Sections of these plaques contained 93 necrotic cores with a cap thickness <0.62mm which were used to generate a geometry-based model. The histological data was used to simulate in vivo MRI images, which were manually delineated by three experienced MRI readers. Caps below the MRI resolution (n=31) were (digitally removed and) reconstructed according to the geometry-based model. Cap thickness and PCS were determined for the ground truth, readers, and reconstructed geometries. Cap thickness was 0.07mm for the ground truth, 0.23mm for the readers, and 0.12mm for the reconstructed geometries. The model predicts cap thickness significantly better than the readers. PCS was 464kPa for the ground truth, 262kPa for the readers and 384kPa for the reconstructed geometries. The model did not predict the PCS significantly better than the readers. The geometry-based model provided a significant improvement for cap thickness estimation and can potentially help in rupture-risk prediction, solely based on cap thickness. Estimation of PCS estimation did not improve, probably due to the complex shape of the plaques.

Stroke in Indigenous Africans, African Americans, and European Americans: Interplay of Racial and Geographic Factors

BACKGROUND AND PURPOSE

The relative contributions of racial and geographic factors to higher risk of stroke in people of African ancestry have not been unraveled. We compared stroke type and contributions of vascular risk factors among indigenous Africans (IA), African Americans (AA), and European Americans (EA).

METHODS

SIREN (Stroke Investigative Research and Educational Network) is a large multinational case-control study in West Africa-the ancestral home of 71% AA-whereas REGARDS (Reasons for Geographic and Racial Differences in Stroke) is a cohort study including AA and EA in the United States. Using harmonized assessments and standard definitions, we compared data on stroke type and established risk factors for stroke in acute stroke cases aged ≥55 years in both studies.

RESULTS

There were 811 IA, 452 AA, and 665 EA stroke subjects, with mean age of 68.0±9.3, 73.0±8.3, and 76.0±8.3 years, respectively (P<0.0001). Hemorrhagic stroke was more frequent among IA (27%) compared with AA (8%) and EA (5.4%; P<0.001). Lacunar strokes were more prevalent in IA (47.1%), followed by AA (35.1%) and then EA (21.0%; P<0.0001). The frequency of hypertension in decreasing order was IA (92.8%), followed by AA (82.5%) and then EA (64.2%; P<0.0001) and similarly for diabetes mellitus IA (38.3%), AA (36.8%), and EA (21.0%; P<0.0001). Premorbid sedentary lifestyle was similar in AA (37.7%) and EA (34.0%) but lower frequency in IA (8.0%).

CONCLUSIONS

Environmental risk factors such as sedentary lifestyle may contribute to the higher proportion of ischemic stroke in AA compared with IA, whereas racial factors may contribute to the higher proportion of hypertension and diabetes mellitus among stroke subjects of African ancestry.