Subacute Stage Of Stroke Research Articles

Epiglottic Retroflexion is a Key Indicator of Functional Recovery of Post-stroke Dysphagia.

ObjectiveTo evaluate the longitudinal changes of swallowing kinematics based on videofluoroscopic swallowing studies (VFSSs) in subacute stroke patients grouped according to the method of dietary intake.MethodsSixty-nine subacute stroke patients who had taken at least 2 successive VFSSs were included. Subjects were allocated into 3 groups according to the degree of swallowing function recovery—not improved group (tube feeding recommended to patients at both studies), improved group (tube feedings recommended initially to patients and oral feeding recommended at follow-up study), and well-maintained group (oral feeding at both studies recommended to patients). Initial VFSS was performed during the subacute stage of stroke, 1 to 12 weeks after the onset of stroke, and follow-up VFSS was performed at least once. Kinematic variables were calculated by two-dimensional motion analysis of multiple structures, including the hyoid bone, epiglottis, and vocal cord. Changes of kinematic variables were analyzed in serial VFSSs.ResultsAt the initial VFSS, the well-maintained group showed significantly larger angles of epiglottic folding than the not improved group, while at the follow-up VFSS, the improved and the well-maintained groups showed significantly larger epiglottic folding angles than the not improved group. The distribution of epiglottic folding angles was in a dichotomous pattern, and each cluster was related to the swallowing function.ConclusionThis study showed that improved epiglottic folding angles are associated with the recovery of the swallowing process and suitability for oral feeding among various kinematic variables in subacute stroke patients.

Brain Functional Networks Study of Subacute Stroke Patients With Upper Limb Dysfunction After Comprehensive Rehabilitation Including BCI Training.

Brain computer interface (BCI)-based training is promising for the treatment of stroke patients with upper limb (UL) paralysis. However, most stroke patients receive comprehensive treatment that not only includes BCI, but also routine training. The purpose of this study was to investigate the topological alterations in brain functional networks following comprehensive treatment, including BCI training, in the subacute stage of stroke. Twenty-five hospitalized subacute stroke patients with moderate to severe UL paralysis were assigned to one of two groups: 4-week comprehensive treatment, including routine and BCI training (BCI group, BG, n = 14) and 4-week routine training without BCI support (control group, CG, n = 11). Functional UL assessments were performed before and after training, including, Fugl-Meyer Assessment-UL (FMA-UL), Action Research Arm Test (ARAT), and Wolf Motor Function Test (WMFT). Neuroimaging assessment of functional connectivity (FC) in the BG was performed by resting state functional magnetic resonance imaging. After training, as compared with baseline, all clinical assessments (FMA-UL, ARAT, and WMFT) improved significantly (p < 0.05) in both groups. Meanwhile, better functional improvements were observed in FMA-UL (p < 0.05), ARAT (p < 0.05), and WMFT (p < 0.05) in the BG. Meanwhile, FC of the BG increased across the whole brain, including the temporal, parietal, and occipital lobes and subcortical regions. More importantly, increased inter-hemispheric FC between the somatosensory association cortex and putamen was strongly positively associated with UL motor function after training. Our findings demonstrate that comprehensive rehabilitation, including BCI training, can enhance UL motor function better than routine training for subacute stroke patients. The reorganization of brain functional networks topology in subacute stroke patients allows for increased coordination between the multi-sensory and motor-related cortex and the extrapyramidal system. Future long-term, longitudinal, controlled neuroimaging studies are needed to assess the effectiveness of BCI training as an approach to promote brain plasticity during the subacute stage of stroke.

Re-initiation of Oral Food Intake Following Enteral Nutrition Alters Oral and Gut Microbiota Communities.

Stroke is associated with multiple forms of disability, including dysphagia. Post-stroke dysphagia increases the risks of pneumonia and mortality and often results in cessation of oral feeding. However, appropriate rehabilitation methods can eventually lead to resumption of oral food intake. This study tried to clarify that re-initiating oral food intake could modify the composition of oral/gut microbial communities in patients with dysphagia. From 78 patients with sub-acute stage of stroke, 11 complete tube feeding subjects without taking antibiotics were enrolled and received rehabilitation for re-initiation of oral food intake, and 8 subjects were brought back to complete oral feeding. Oral and gut microbiota community profiles were evaluated using 16S rRNA sequencing of the saliva and feces samples before and after re-initiation of oral food intake in patients recovering from enteral nutrition under the same nutrient condition. Standard nutrition in the hospital was 1,840 kcal, including protein = 75 g, fat = 45 g, and carbohydrates = 280 g both for tube and oral feeding subjects. Oral food intake increased oral and gut microbiome diversity and altered the composition of the microbiome. Oral and gut microbiome compositions were drastically different; however, the abundance of family Carnobacteriaceae and genus Granulicatella was increased in both the oral and gut microbiome after re-initiation of oral food intake. Although oral microbiota showed more significant changes than the gut microbiota, metagenome prediction revealed the presence of more differentially enriched pathways in the gut. In addition, simpler co-occurrence networks of oral and gut microbiomes, indicating improved dysbiosis of the microbiome, were observed during oral feeding as compared to that during tube feeding. Oral food intake affects oral and gut microbiomes in patients recovering from enteral nutrition. Rehabilitation for dysphagia can modify systemic health by increasing the diversity and altering the composition and co-occurrence network structure of oral and gut microbial communities.

MicroRNA expression profile in patients in the early stages of ischemic stroke

Stroke is one of the leading causes of death and disability in the population, has a complex multifactorial nature and develops through the interaction of environmental factors and genetic predisposition, the pattern and mechanisms of which have been insufficiently studied. Ischemic stroke (IS) is most commonly encountered. Objective: to investigate the differential expression of microRNAs (miRNAs) in the plasma of patients in the acute and subacute stages of stroke. Patients and methods. The investigation enrolled 10 patients (5 men and 5 women; mean age, 64.5 years) with IS and 10 gender- and agematched volunteers (a control group). A real-time polymerase chain reaction (PCR) was used to analyze the expression of 45 miRNAs isolated from the plasma samples of the patients on days 1 and 8 after onset of IS and isolated once from those of the controls. Results. A list of 45 miRNAs, that might be potential biomarkers and/or prognostic factors of stroke, was compiled. The investigation showed a decrease in let-7i-3p and miR-23a-3p miRNA expression in patients on the first day after onset of IS compared to the control group. The expression of miR-23a-3p increased in the patients at 8 days after IS. The patients with IS and the controls both showed gender differences in the expression of let-7i-5p and miR-92b-3p. Conclusion. The in-silico analysis revealed specific miRNA clusters associated with the peculiarities of clinical manifestations of IS. This may suggest that the patients with the favorable and unfavorable course of stroke may have its different molecular basis. In addition, it is necessary to take into account gender differences in the expression of individual miRNAs in assessing their significance in the pathogenesis and prognosis of IS.

Inhibition of Notch1 Signaling at the Subacute Stage of Stroke Promotes Endogenous Neurogenesis and Motor Recovery After Stroke.

Background and Purpose: It is still not clear whether Notch1 signaling inhibition can promote functional outcomes after stroke, given that it plays time-dependent roles in the sequential process of endogenous neurogenesis. The purpose of this study was to identify the appropriate time frame for Notch1 signaling inhibition according to the temporal evolution of Notch1 signaling activation and the responses of neural stem cells (NSCs), in order to target it for therapeutic intervention and stimulate neurorestorative strategies after stroke.Methods: Sprague-Dawley (SD) rats were subjected to 90-min of middle cerebral artery occlusion (MCAO). Rats were sacrificed before, and at day 1, day 2, day 3, day 4, and day 7 after ischemia for immunohistochemical analysis of the Notch intracellular domain (NICD), Nestin and doublecortin (Dcx). Next, MCAO rats were treated with the γ-secretase inhibitor N-[N-(3,5-di uorophenacetyl)-1-alanyl]-S-phenylglycine t-butylester (DAPT) or with saline at day 4 after ischemia, and subsequently evaluated with behavioral test analysis and magnetic resonance imaging (MRI). The rat brains were then harvested for immunohistochemical analysis of Dcx, NeuN and myelin basic protein (MBP) at 2, 3, 4, and 8 weeks.Results: Notch1 signaling was maximally activated at day 3 after ischemia in parallel with the temporal evolution of NSCs. Inhibiting Notch1 signaling at day 4 after reperfusion with DAPT further promoted recovery of MRI parameters of the corticospinal tract (CST) and the functional outcomes, concomitantly with an increase in neuroblasts, their migration to the ischemic boundary, and potential differentiation to mature neurons, as well as the amelioration of axonal bundle integrity.Conclusion: Inhibition of Notch1 signaling at the subacute stage of stroke could maximally promote endogenous neurogenesis and axonal reorganization.

Long-term use benefits of personal frequency-modulated systems for speech in noise perception in patients with stroke with auditory processing deficits: a non-randomised controlled trial study

ObjectivesApproximately one in five stroke survivors suffer from difficulties with speech reception in noise, despite normal audiometry. These deficits are treatable with personal frequency-modulated systems (FMs). This study aimed to...

Subacute Percutaneous Cerebral Balloon Angioplasty for Middle Cerebral Artery Occlusion in Patients with Internal Border Zone Infarcts.

Background We report our initial experiences of subacute percutaneous cerebral balloon angioplasty (PTCBA) for atherothrombotic middle cerebral artery (MCA) occlusion in patients with internal border zone (IBZ) infarcts more than 1 week after stroke onset. Methods Included in the retrospective analysis were patients (1) who were admitted to our institution between 3 and 72 hours after an atherothrombotic stroke onset, (2) whose diffusion-weighted image at admission showed small high-intensity lesions in the IBZ area, (3) whose magnetic resonance angiography at admission displayed the MCA occlusion, (4) whose computed tomography scans on day 7 showed the IBZ infarcts, (5) whose National Institutes of Health Stroke Scale (NIHSS) score was ≥ 10 on day 7, and (6) whose neurologic symptoms deteriorated day by day within 7 days of onset (a > 4-point increase on the NIHSS) despite medical therapy. Results Ten patients met our criteria and were informed of their treatment options including angioplasty and/or stenting for atherothrombotic MCA occlusion in a subacute stroke stage. Four patients gave written informed consent and underwent subacute PTCBA; six did not. Although there were no significant differences in the prestroke modified Rankin Scale (mRS), NIHSS on admission and NIHSS on day 7 after onset between the two groups, 3-month mRS score (median) was 3 in the PTCBA group and 5 in the medical treatment group (p < 0.05). Conclusion Subacute PTCBA for atherothrombotic MCA occlusion may be effective in improving long-term clinical outcome in patients with IBZ infarcts.

Hybrid Assistive Limb enhances the gait functions in sub-acute stroke stage: A multi single-case study

Hybrid Assistive Limb enhances the gait functions in sub-acute stroke stage: A multi single-case study

The Fugl–Meyer assessment of the upper extremity: reliability, responsiveness and validity of the Danish version

Objective: To translate the Fugl-Meyer Assessment of the Upper Extremity (FMA-UE) into Danish and to establish the inter-tester reliability, responsiveness, Minimal Clinically Important Difference (MCID) and concurrent validity of the FMA-UE in a population of stroke patients. Method: The translation was conducted in accordance with the principles outlined by the ISPOR Task Force for Translation and Cultural Adaption. Inter-rater reliability was assessed at baseline. Each patient was tested by two examiners and inter class correlation (ICC) was calculated. Responsiveness was assessed using receiver operating characteristic (ROC) curve statistics. The FMA-UE change score was used to assess sensitivity and specificity and to correctly determine which patients had improved. The MCID and the area under the curve (AUC) were established using the ROC. The FMA-UE’s concurrent validity with the Motor Assessment Scale was determined using Spearman’s rank correlation. Setting: The study took place at Skive Neurorehabilition, Denmark from May 2014 to February 2015. Participants: Inpatients, who were in the acute to sub-acute stage of stroke and aged > 18 years. Interventions: Not applicable. Main outcome measure: The FMA-UE. Results: In 50 inpatients the ICC was 0.95, AUC was 0.87, with a sensitivity of 77%, a specificity of 89% and an MCID ≥ 4. Concurrent validity was high, with r = 0.94–0.95. Conclusion: The FMA-UE was successfully translated into Danish. An MCID ≥ 4 was found. This study provides evidence that the FMA-UE is a reliable, responsive and valid instrument for measuring upper limb impairment after stroke.Implications for rehabilitationOne of the most widely recognized measures of upper extremity motor impairment post-stroke is the Fugl-Meyer Assessment of the Upper Extremity (FMA-UE).The psychometric properties of a measurement depends on the population and setting in which it is used.In this study, the FMA-UE is translated into Danish and the psychometric properties of FMA-UE is determined in a Danish population of patients with stroke.The FMA-UE is now available to use for clinicians in Denmark.

Frontal Cortical Atrophy as a Predictor of Poststroke Apathy.

The aim of the study was to identify associations between the symptoms of poststroke apathy and sociodemographic, stroke-related (severity of stroke, degree of disability, and performance in activities of daily living), and radiological correlates. We determined the degree of cortical and subcortical brain atrophy, the severity of white matter and basal ganglia lesions on baseline computed tomography (CT) scans, and the localization of acute ischemia on control CT or magnetic resonance imaging scans in subacute stages of stroke. During follow-up examinations, in addition to the assessment of apathy symptoms using the Apathy Scale, we also evaluated symptoms of depression and anxiety using the Hospital Anxiety and Depression Scale. The study included 47 consecutive patients with acute ischemic stroke. Correlates significantly associated with apathy, determined at baseline and during follow-up, were entered into the "predictive" and "associative" multiple regression models, respectively. Frontal cortical atrophy and symptoms of depression were most strongly associated with poststroke apathy symptoms. In order to model an interrelation between both cortical atrophy and white matter lesions and aging, we supplemented 2 additional "predictive" models using interaction variables, whereby we confirmed the role of frontal cortical atrophy as a predictor of poststroke apathy also as a function of the increasing age of patients.

Neuronal deficiency of HIF prolyl 4-hydroxylase 2 in mice improves ischemic stroke recovery in an HIF dependent manner

Hypoxia inducible factors (HIFs) mediate the endogenous adaptive responses to hypoxia. HIF prolyl 4-hydroxylase domain proteins (PHD) are important suppressors of the HIF pathway. Recently, we demonstrated that neuron-specific deletion of Phd2 reduces cerebral tissue damage in the very acute phase of ischemic stroke. In the present study, we investigated whether neuronal Phd2 ablation is likewise beneficial for stroke recovery, and aimed to identify underlying cellular mechanisms. Mice underwent permanent occlusion of the distal middle cerebral artery (pdMCAO) for either 7days (sub-acute stage) or 30days (chronic stage). One week after pdMCAO the infarct size of Phd2-deficient mice was significantly reduced as compared to wild-type (WT) mice. Accordingly, Phd2-deficient animals showed less impaired sensorimotor function. Neuronal loss of Phd2 upregulated vascular endothelial growth factor (VEGF) and significantly increased microvascular density along the infarct border in the sub-acute stage of stroke. Phd2-deficient mice showed reduced expression of pro-inflammatory cytokines and increased numbers of resting microglia/macrophages and reactive astrocytes within peri-infarct regions in comparison to WT littermates. Finally, brain tissue protection and increased angiogenesis upon sub-acute ischemic stroke was completely absent in Phd2 knockout mice that were additionally deficient for both Hif1a and Hif2a. Our findings suggest that lack of PHD2 in neurons improves histological and functional long-term outcome from ischemic stroke at least partly by amplifying endogenous adaptive neovascularization through activation of the HIF-VEGF axis.

Sleep Disturbances at 3 Months after Cerebral Infarction

Background: Post-stroke sleep disturbances (PSSD) are common and associated with various adverse outcomes. However, PSSD in the sub-acute stages of stroke have been scarcely studied. We aimed to evaluate the characteristics of and the factors related to PSSD in stroke patients 3 months post stroke. Methods: A total of 199 patients were evaluated for PSSD at 3 months after stroke. The qualities of nighttime sleep and excessive daytime sleepiness (EDS) were assessed using the Verran Snyder-Halpern sleep scale and Epworth Sleepiness Scale, respectively. Presence of motor dysfunction and post-stroke pain, post-stroke depression, fatigue and social support were evaluated. Results: Eighty-eight patients (44.2%) had poor quality of nighttime sleep. Twenty-eight patients (14.4%) reported EDS. Poor quality of nighttime sleep was independently associated with depression (p = 0.044) and EDS (p = 0.041) whereas fatigue (p < 0.001) and poor nighttime sleep (p = 0.045) were independently associated with EDS. Post-stroke pain and social support showed no association with PSSD. Conclusions: We found that the occurrence of PSSD 3 months after stroke is common. Although causality remained to be determined, depression and nighttime sleep disturbances were related, whereas fatigue and nighttime sleep disturbances were related to EDS.

Abstract NS8: Prevalence and Relating Factors of Sleep Disturbances at 3 Months Post Stroke

Background: Post-stroke sleep disturbances (PSSD) are common and associated with various adverse outcomes. However, PSSD in the subacute stages of stroke have been scarcely studied. We aimed to evaluate the characteristics of and the factors related to PSSDs in stroke patients 3 months post-stroke. Methods: A total of 199 patients were evaluated for PSSD at 3 months after stroke. The quality of nighttime sleep and excessive daytime sleepiness (EDS) were assessed using the Verran Snyder-Halpern sleep scale and Epworth Sleepiness Scale, respectively. Presence of motor dysfunction and post-stroke pain, post-stroke depression, fatigue, and social support were evaluated. Results: Eighty eight patients (44.2%) had poor quality of night time sleep. Twenty eight patients (14.4%) reported EDS. Poor quality of sleep was independently associated with depression (p = 0.044) and EDS (p = 0.041) whereas fatigue (p = 0.000) and poor nighttime sleep (p = 0.045) were independently associated with EDS. Post-stroke pain and social support showed no association with PSSD. Conclusions: We found that PSSD 3 month post-stroke is common. Although causality remained to be determined, depression and nighttime sleep disturbances were related, whereas fatigue and nighttime sleep disturbances were related to EDS.

Comparison of Diffusion Tensor Tractography and Motor Evoked Potentials for the Estimation of Clinical Status in Subacute Stroke.

ObjectiveTo compare diffusion tensor tractography (DTT) and motor evoked potentials (MEPs) for estimation of clinical status in patients in the subacute stage of stroke.MethodsPatients with hemiplegia due to stroke who were evaluated using both DTT and MEPs between May 2012 and April 2015 were recruited. Clinical assessments investigated upper extremity motor and functional status. Motor status was evaluated using Medical Research Council grading and the Fugl-Meyer Assessment of upper limb and hand (FMA-U and FMA-H). Functional status was measured using the Modified Barthel Index (MBI). Patients were classified into subgroups according to DTT findings, MEP presence, fractional anisotropy (FA) value, FA ratio (rFA), and central motor conduction time (CMCT). Correlations of clinical assessments with DTT parameters and MEPs were estimated.ResultsFifty-five patients with hemiplegia were recruited. In motor assessments (FMA-U), MEPs had the highest sensitivity and negative predictive value (NPV) as well as the second highest specificity and positive predictive value (PPV). CMCT showed the highest specificity and PPV. Regarding functional status (MBI), FA showed the highest sensitivity and NPV, whereas CMCT had the highest specificity and PPV. Correlation analysis showed that the resting motor threshold (RMT) ratio was strongly associated with motor status of the upper limb, and MEP parameters were not associated with MBI.ConclusionDTT and MEPs could be suitable complementary modalities for analyzing the motor and functional status of patients in the subacute stage of stroke. The RMT ratio was strongly correlated with motor status.

Robot training for hand motor recovery in subacute stroke patients: A randomized controlled trial

BackgroundEvidence of superiority of robot training for the hand over classical therapies in stroke patients remains controversial. During the subacute stage, hand training is likely to be the most useful. AimTo establish whether robot active assisted therapies provides any additional motor recovery for the hand when administered during the subacute stage (<4 months from event) in a Mexican adult population diagnosed with stroke. HypothesisCompared to classical occupational therapy, robot based therapies for hand recovery will show significant differences at subacute stages. Trial designA randomized clinical trial. MethodsA between subjects randomized controlled trial was carried out on subacute stroke patients (n = 17) comparing robot active assisted therapy (RT) with a classical occupational therapy (OT). Both groups received 40 sessions ensuring at least 300 repetitions per session. Treatment duration was (mean ± std) 2.18 ± 1.25 months for the control group and 2.44 ± 0.88 months for the study group. The primary outcome was motor dexterity changes assessed with the Fugl-Meyer (FMA) and the Motricity Index (MI). ResultsBoth groups (OT: n = 8; RT: n = 9) exhibited significant improvements over time (Non-parametric Cliff's delta-within effect sizes: dwOT-FMA = 0.5, dwOT-MI = 0.5, dwRT-FMA = 1, dwRT-MI = 1). Regarding differences between the therapies; the Fugl-Meyer score indicated a significant advantage for the hand training with the robot (FMA hand: WRS: W = 8, p <0.01), whilst the Motricity index suggested a greater improvement (size effect) in hand prehension for RT with respect to OT but failed to reach significance (MI prehension: W = 17.5, p = 0.080). No harm occurred. ConclusionsRobotic therapies may be useful during the subacute stages of stroke – both endpoints (FM hand and MI prehension) showed the expected trend with bigger effect size for the robotic intervention. Additional benefit of the robotic therapy over the control therapy was only significant when the difference was measured with FM, demanding further investigation with larger samples. Implications of this study are important for decision making during therapy administration and resource allocation.

Cerebral lesions of DWI hyperintensity in patients with subacute stroke assessed by intravoxel incoherent motion technique

To investigate the cerebral lesions of diffusion weighted imaging (DWI) hyperintensity in patients with subacute stroke with intravoxel incoherent motion (IVIM) technique. The clinical data of 20 patients with ischemic stroke (3 to 7 d after onset) who underwent DWI and IVIM scanning between June 2014 and July 2015, were retrospectively analyzed. The parameters from IVIM including slow diffusion coefficient (D), fast diffusion coefficient (D(*)) and perfusion fraction (f) were processed. DWI hyperintensity was segmented by its signal intensity greater than the mean+2 standard deviations of the value in the homologous contralateral region. Then, DWI hyperintensity was classified into two regions of interest (ROIs): infarction core and peri-core with the ADC threshold of 0.55 × 10⁻³ mm²/s. The mirrored ROIs of infarction core and peri-core were also obtained. Then, we measured the values of ADC and D, D(*) and f in these ROIs. The ratios of ADC (rADC), D (rD), D(*) (rD(*)) and f (rf) were also calculated (e.g., rADC=ADCinfarction core/ADCmirrored region). Compared with mirrored region, ADC, D and f in the infarction core region decreased by 45% (P<0.001), 42% (P<0.001) and 32% (P<0.001), respectively; while ADC, D and f in the peri-core region decreased by 22% (P<0.001), 32% (P<0.001) and 8% (P=0.009), respectively. The values of rADC, rD, rD(*) and rf in the infarction core region were significantly lower than those in the peri-core region (all P<0.001). Pearson analysis showed that rADC was positively correlated with rf in the peri-core region (r=0.467, P=0.038). During subacute stage of stroke, compared to the infarction core region within DWI hyperintensity, D and f increase in the peri-core region of DWI hyperintensity, reflecting the increased water diffusion in microstructure and perfusion volume in microvasculature. This result shows that the potential reason for the heterogeneous ADC signal is associated with the disappearance of cellular edema and microvascular compensatory with increased blood volume.

Is motor imagery really a window for studying stroke recovery at subacute stage?

Because of similarities with overt movement execution, motor imagery is considered as a way to study motor recovery after stroke. However, some studies could not correlate motor imagery abilities with motor function at the subacute stage of stroke challenging motor imagery as a substitute to motor execution in these patients. The aim of this study was to compare explicit and implicit motor imagery abilities in stroke patients and in healthy subjects, to correlate those with motor function and investigate the role of lesion side and location on performances. Twenty-two stroke patients at the subacute stage and 22 healthy volunteers performed implicit and explicit motor imagery tasks (Hand Laterality Judgment Task [HJLT], imagined and executed self-paced hand movements) and a motor assessment (maximal grip strength, Jebsen-Taylor Test [JTT]). Differences between healthy subjects and patients and the impact of lesion side and location on motor imagery were studied using ANOVA. Correlation coefficients were used to analyze the relationship between motor imagery abilities and motor function. For implicit imagery in HLJT, stroke patients had slower reaction times ( P ≤ 0.03) and tended to have higher rates of errors ( P = 0.05) but shared similar characteristics (angle effect: P ≤ 0.01) compared to healthy subjects. For explicit imagery, patients were slower than healthy subjects for the affected hand in the executed condition ( P = 0.04) and tended to be slower in the imagined condition ( P = 0.06). Patients and healthy subjects exhibited a temporal congruence ( P ≤ 0.004) except for right-sided strokes ( n = 8) and patients with parietal damages ( n = 9) for the affected hand. Finally, in stroke patients, implicit and explicit imagery performances were not correlated with upper limb function. Caution must be taken to use motor imagery as a tool for monitoring stroke recovery because subacute stroke patients exhibit motor imagery deficits, independently of the severity of motor impairment.

On the importance of cognitive profiling: A graphical modelling analysis of domain-specific and domain-general deficits after stroke

Cognitive problems following stroke are typically analysed using either short but relatively uninformative general tests or through detailed but time consuming tests of domain specific deficits (e.g., in language, memory, praxis). Here we present an analysis of neuropsychological deficits detected using a screen designed to fall between other screens by being ‘broad’ (testing multiple cognitive abilities) but ‘shallow’ (sampling the abilities briefly, to be time efficient) – the BCoS. Assessment using the Birmingham Cognitive Screen (BCoS) enables the relations between ‘domain specific’ and ‘domain general’ cognitive deficits to be evaluated as the test generates an overall cognitive profile for individual patients. We analysed data from 287 patients tested at a sub-acute stage of stroke (<3 months). Graphical modelling techniques were used to investigate the associative structure and conditional independence between deficits within and across the domains sampled by BCoS (attention and executive functions, language, memory, praxis and number processing). The patterns of deficit within each domain conformed to existing cognitive models. However, these within-domain patterns underwent substantial change when the whole dataset was modelled, indicating that domain-specific deficits can only be understood in relation to linked changes in domain-general processes. The data point to the importance of using over-arching cognitive screens, measuring domain-general as well as domain-specific processes, in order to account for neuropsychological deficits after stroke. The paper also highlights the utility of using graphical modelling to understand the relations between cognitive components in complex datasets.

Attenuation of acute stroke injury in rat brain by minocycline promotes blood-brain barrier remodeling and alternative microglia/macrophage activation during recovery.

BackgroundMinocycline reduces reperfusion injury by inhibiting matrix metalloproteinases (MMPs) and microglia activity after cerebral ischemia. Prior studies of minocycline investigated short-term neuroprotective effects during subacute stage of stroke; however, the late effects of minocycline against early reperfusion injury on neurovascular remodeling are less well studied. We have shown that spontaneous angiogenesis vessels in ischemic brain regions have high blood–brain barrier (BBB) permeability due to lack of major tight junction proteins (TJPs) in endothelial cells at three weeks. In the present study, we longitudinally investigated neurological outcome, neurovascular remodeling and microglia/macrophage alternative activation after spontaneous and minocycline-induced stroke recovery.MethodsAdult spontaneously hypertensive rats had a 90 minute transient middle cerebral artery occlusion. At the onset of reperfusion they received a single dose of minocycline (3 mg/kg intravenously) or a vehicle. They were studied at multiple time points up to four weeks with magnetic resonance imaging (MRI), immunohistochemistry and biochemistry.ResultsMinocycline significantly reduced the infarct size and prevented tissue loss in the ischemic hemispheres compared to vehicle-treated rats from two to four weeks as measured with MRI. Cerebral blood flow measured with arterial spin labeling (ASL) showed that minocycline improved perfusion. Dynamic contrast-enhanced MRI indicated that minocycline reduced BBB permeability accompanied with higher levels of TJPs measured with Western blot. Increased MMP-2 and −3 were detected at four weeks. Active microglia/macrophage, surrounding and within the peri-infarct areas, expressed YM1, a marker of M2 microglia/macrophage activation, at four weeks. These microglia/macrophage expressed both pro-inflammatory factors tumor necrosis factors-α (TNF-α) and interleukin-1β (IL-1β) and anti-inflammatory factors transforming growth factor-β (TGF-β) and interleukin-10 (IL-10). Treatment with minocycline significantly reduced levels of TNF-α and IL-1β, and increased levels of TGF-β, IL-10 and YM1.ConclusionsEarly minocycline treatment against reperfusion injury significantly promotes neurovascular remodeling during stroke recovery by reducing brain tissue loss, enhancing TJP expression in ischemic brains and facilitating neuroprotective phenotype alternative activation of microglia/macrophages.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-015-0245-4) contains supplementary material, which is available to authorized users.

Can Motor Evoked Potentials Be an Objective Parameter to Assess Extremity Function at the Acute or Subacute Stroke Stage?

ObjectiveTo investigate whether motor evoked potential (MEP) amplitude ratio measurements are sufficiently objective to assess functional activities of the extremities. We also delineated the distribution between the presence or absence of MEPs and the Medical Research Council (MRC) scale for muscle strength of the extremities.MethodsWe enrolled 183 patients with first-ever unilateral hemiplegia after stroke. The MEP parameters were amplitude ratio (amplitude of affected side/amplitude of unaffected side) recorded at the first dorsal interosseous (FDI) and tibialis anterior (TA) muscles. We performed frequency analyses using the MRC scale for muscle strength and the presence or absence of evoked MEPs. Change on the MRC scale, hand function tests (HFTs), and the Modified Barthel Index (MBI) subscore were compared between the evoked MEP and absent MEP groups using the independent t-test. Receiver operating characteristic curves were used to determine the optimal cutoff scores for the MEP amplitude ratio using the HFT results and MBI subscores. Correlations between the MEP amplitude ratio and the MRC scale, HFTs, and MBI subscore were analyzed.ResultsAbout 10% of patients with MRC scale grades 0-2 showed evoked MEPs at the FDI muscle, and 4% of patients with MRC scale grades 3-5 did not show MEPs. About 18% of patients with MRC scale grades 0-2 showed evoked MEPs at the TA muscle, and 4% of patients with MRC scale grades 3-5 did not show MEPs. MEP amplitude increased with increasing MRC scale grade. The evoked MEP group had more significant changes on the MRC scale, HFT, and the climbing stair score on the MBI than those in the group without MEPs. Larger MEP amplitude ratios were observed in patients who had more difficulty with the HFTs and ambulation. The MEP amplitude ratio was significantly correlated with the MRC scale, HFT, and MBI subscore.ConclusionWe conclude that the MEP amplitude ratio may be useful to predict functional status of the extremities in patients who suffered stroke.