Alteration in brain functional connectivity in patients with post-stroke cognitive impairment during memory task: A fNIRS study

ObjectiveThis study attempted to evaluate the functional connectivity (FC) in relevant cortex areas during three memory tasks using the functional near-infrared spectroscopy (fNIRS) method to expound the neural mechanisms in individuals with post-stroke cognitive impairment (PSCI).MethodsShort-term memory and visuospatial abilities were assessed using the clock drawing test, digit span test, and Corsi Block-tapping tests with simultaneous fNIRS. The oxygenated hemoglobin concentration signals were recorded from the bilateral motor sense cortex (LMS/RMS) and prefrontal lobe (LPFT/PFT/RPFT) of 19 subjects with cognitive impairment (PSCI group), 27 stroke subjects (STR group) and 26 healthy subjects (HC group).ResultsMMSE scores were positively correlated with the clock drawing test and digit span test scores but not with Corsi Block-tapping scores. During each test, functional connectivity between the bilateral MS (LMS/RMS) was highest within each group, but the functional connectivity between motor sense cortex and frontal lobe was lowest. PSCI group showed decreased FC between bilateral motor sense cortex (P < 0.05) and between motor sense cortex and frontal lobe (P > 0.05) during clock drawing test and Corsi Block-tapping test while decreased FC between each region of interest during digit span test with no significant difference. Functional connectivity levels were closely related to MMSE scores.ConclusionsDecreased functional connectivity level may be a marker of impaired cognitive function in post-stroke cognitive impairment. The fNIRS-based functional connectivity provides a non-invasive method to recognize cognitive impairment post-stroke. Functional connectivity changes may help to further understand the neural mechanisms of cognitive impairment post stroke.     

Resting state alpha-band functional connectivity and recovery after stroke

After cerebral ischemia, disruption and subsequent reorganization of functional connections occur both locally and remote to the lesion. However, the unpredictable timing and extent of sensorimotor recovery reflects a gap in understanding of these underlying neural mechanisms. We aimed to identify the plasticity of alpha-band functional neural connections within the perilesional area and the predictive value of functional connectivity with respect to motor recovery of the upper extremity after stroke. Our results show improvements in upper extremity motor recovery in relation to distributed changes in MEG-based alpha band functional connectivity, both in the perilesional area and contralesional cortex. Motor recovery was found to be predicted by increased connectivity at baseline in the ipsilesional somatosensory area, supplementary motor area, and cerebellum, contrasted with reduced connectivity of contralesional motor regions, after controlling for age, stroke onset-time and lesion size. These findings support plasticity within a widely distributed neural network and define brain regions in which the extent of network participation predicts post-stroke recovery potential.     

Additional therapy promotes a continued pattern of improvement in upper-limb function and independence post-stroke

BackgroundUpper-limb motor impairment after stroke is common and disabling. Growing evidence suggests that rehabilitation is effective in the chronic period. However, there is limited knowledge on the effects of ongoing targeted rehabilitation programs on patient outcomes.ObjectivesThis study investigated the effects of delivering two programs of dose-matched evidence-based upper-limb rehabilitation to community-dwelling post-acute stroke patients with low, moderate and high motor-function.Materials and methods12 patients (2 female) aged 50.5±18.2 years and 13.8±10.8 months post-stroke completed 2-weeks of modified-Constraint-Induced Movement Therapy followed by 2-weeks of Wii-based Movement Therapy after a mean interval of 9.6±1.1 months (range 6-19months). Function was assessed at 6 time points (i.e. before and after each therapy program and 6-month follow-up after each program). Primary outcome measures were the Wolf Motor Function Test timed-tasks (WMFT-tt), upper-limb Fugl-Meyer Assessment (F-M) and the Motor Activity Log Quality of Movement Scale (MALQOM). Improvement and maintenance was analyzed using Paired T-Tests and Wilcoxon Signed Rank Tests.ResultsUpper-limb function significantly improved on all primary outcome measures with the first therapy program (WMFT-tt p=0.008, F-M p=0.007 and MALQOM p<0.0001). All scores continued to improve with the second therapy program with significant improvements in the F-M (p=0.048) and the MALQOM (p=0.001).ConclusionsAll patients showed a pattern of continued improvement in upper-limb motor-function and independence in activities of daily living. These improvements demonstrate the benefit of ongoing post-stroke rehabilitation for community-dwelling stroke survivors for individuals of varying baseline functional status.     

Changes of cortico-cortical neural connections associated with motor functional recovery after stroke

ObjectivesDuring functional recovery after stroke, some neural connections in the brain are augmented and new neural networks are constructed to compensate for impaired neurological functions. Recently, it was reported that the extent of cortico-cortical neural connections can be estimated by correlation analysis based on electroencephalography (EEG). The purpose of this study was to investigate changes of correlation coefficients in the cerebral cortex with motor functional recovery after stroke.Materials and methodsTwenty-two post-stroke hemiparetic patients admitted to our rehabilitation ward (mean age at admission: 71.4 ± 12.9 years old), were studied. For the evaluation of hemiparesis, Fugl-Meyer Assessment (FMA) was applied. All subjects underwent EEG with electrodes placed according to the international 10-20 system for correlation analysis, on admission to our ward and 4 weeks after admission. EEG data were analyzed with the program software FOCUS (NIHON KOHDEN, Japan), and squared correlation coefficients in some cortico-cortical areas of the cerebral cortex were calculated.ResultsThe correlation coefficients in some cortico-cortical areas of the lesional hemisphere, such as C3-F3 or C4-F4, C3-F7 or C4-F8, and F3-F7 or F4-F8, significantly increased with rehabilitation training. The change of the correlation coefficient in F3-F7 or F4-F8 and F7-T3 or F8-T4 in the lesional hemisphere was significantly correlated with the change of the upper-limb FMA.ConclusionsThe augmentation of cortico-cortical connections, represented by an increase of the correlation coefficient in the lesional hemisphere, may contribute to motor functional recovery, especially in hemiparetic upper limbs, after stroke.     

Factors related to daily step counts of stroke patients during hospitalization in a convalescent rehabilitation ward

ObjectivesClarifying the factors related to decreased physical activity in post-stroke patients is essential for effective disease management. This study aimed to examine the factors influencing the amount of daily steps taken by post-stroke patients in a convalescent rehabilitation ward during activities other than rehabilitation (non-rehabilitation steps).Materials and methodsEighty-nine post-stroke patients (60.8±14.4 years; 55 men) were enrolled. The inclusion criteria were walking independently within the ward and having a walking speed of ≥24 m/min. Data on patient clinical characteristics including age, sex, body mass index, stroke type, hemiparetic side, and time from stroke onset were collected. Stroke impairment and motor and cognitive functional disabilities were assessed using the Stroke Impairment Assessment Set and the Functional Independence Measure, respectively. The non-rehabilitation steps were calculated by subtracting the steps during the rehabilitation activities from the total steps using Fitbit Flex2.ResultsThe average number of non-rehabilitation steps was 4,523±2,339 steps/day. The hierarchical multiple regression analysis revealed that sex, motor disability, and the interaction term of stroke impairment with cognitive disability were significantly related to non-rehabilitation steps. Simple slope analysis demonstrated that the stroke impairment slope was steeper at lower levels than at higher levels of cognitive disability for non-rehabilitation steps.ConclusionsIn addition to independent effects of sex and motor disability, this study found that stroke impairment and cognitive disability were interactively related to non-rehabilitation steps in post-stroke patients in a convalescent rehabilitation ward. These findings may provide useful information for managing physical activity in post-stroke patients after hospital discharge.     

Mood and Cognitive Trajectories Over the First Year after Mild Ischemic Stroke

ObjectivesCognitive and mood dysfunction are major contributors to post-stroke disability. The longer-term trajectories of mood and cognition post-stroke remain unclear, as do which cognitive domains decline, improve, or remain stable after stroke, and in which patients. We aimed to characterize the cognitive trajectories of mild ischemic stroke survivors over one year compared to stroke-free controls, and to investigate whether symptoms of anxiety and depression were associated with cognitive function.Materials and methodsAll participants were tested with a neuropsychological test battery at 3-months and 12-months post-stroke, assessing attention/processing speed, memory, visuospatial function, executive function, and language. Anxiety and depression symptomatology were also assessed at both timepoints.ResultsStroke participants (N=126, mean age 68.44 years ±11.83, 87 males, median [Q1, Q3] admission NIHSS=2 [1, 4]) performed worse on cognitive tests and endorsed significantly higher depression and anxiety symptomatology than controls (N=40, mean age=68.82 years ±6.33, 25 males) at both timepoints. Mood scores were not correlated with cognitive performance. Stroke participants' scores trended higher across cognitive domains from 3- to 12-months but statistically significant improvement was only observed on executive function tasks.ConclusionStroke participants performed significantly worse than controls on all cognitive domains following mild ischemic stroke. Stroke participants only exhibited statistically significant improvement on executive function tasks between 3- and 12- months. Whilst anxiety and depression symptoms were higher in stroke participants, this was not correlated with cognitive performance. Further studies are needed to understand factors underlying cognitive recovery and decline after stroke.     

Motor Impairment Three Months Post Stroke Implies A Corresponding Cognitive Deficit

BackgroundWhile both motor and cognitive impairment are common after stroke, the focus of (early) treatment has always been on motor deficit.AimsThe objective of the current study was to explore the link between motor and cognitive performance in stroke patients and to examine whether motor performance is associated with cognitive functioning at three months post stroke.MethodsIn both stroke patients (n = 142) and controls (n = 135), with the groups matched on age, gender and premorbid IQ, motor functioning was evaluated using both objective (Purdue Pegboard Test) and subjective measures (specific items from the Frenchay Activities Index and Barthel Index). Cognition, specifically information processing speed, working memory and cognitive flexibility, was assessed using objective tasks. The data were analyzed using Pearson product-moment correlation coefficients and logistic regression.ResultsSignificant correlations between motor and cognitive functioning were found in stroke patients. The objective motor task was stronger than subjective measures in statistically explaining and predicting cognitive deficit, irrespective of stroke severity.ConclusionsWe conclude that motor impairment at three months post-stroke should serve as a ‘red flag’ for professionals: cognitive impairment is likely and should also be evaluated.     

Risk Prediction of Cognitive Decline after Stroke

Background and purposeCognitive decline is one of the major outcomes after stroke. We have developed and evaluated a risk predictive tool of post-stroke cognitive decline and assessed its clinical utility.MethodsIn this population-based cohort, 4,783 patients with first-ever stroke from the South London Stroke Register (1995-2010) were included in developing the model. Cognitive impairment was measured using the Mini Mental State Examination (cut off 24/30) and the Abbreviated Mental Test (cut off 8/10) at 3-months and yearly thereafter. A penalised mixed-effects linear model was developed and temporal-validated in a new cohort consisted of 1,718 stroke register participants recruited from (2011-2018). Prediction errors on discrimination and calibration were assessed. The clinical utility of the model was evaluated using prognostic accuracy measurements and decision curve analysis.ResultsThe overall predictive model showed good accuracy, with root mean squared error of 0.12 and R2 of 73%. Good prognostic accuracy for predicting severe cognitive decline was observed AUC: (88%, 95% CI [85-90]), (89.6%, 95% CI [86-92]), (87%, 95% CI [85-91]) at 3 months, one and 5 years respectively. Average predicted recovery patterns were analysed by age, stroke subtype, Glasgow-coma scale, and left-stroke and showed variability.Decisioncurve analysis showed an increased clinical benefit, particularly at threshold probabilities of above 15% for predictive risk of cognitive impairment.ConclusionsThe derived prognostic model seems to accurately screen the risk of post-stroke cognitive decline. Such prediction could support the development of more tailored management evaluations and identify groups for further study and future trials.     

Uncharted territory: The feasibility of serial computerised cognitive assessment the first week post-stroke

BackgroundCognitive impairment is common and problematic post-stroke, yet vital information to understand early cognitive recovery is lacking. To examine early cognitive recovery, it is first necessary to establish the feasibility of repeat cognitive assessment during the acute post-stroke phase.ObjectiveTo determine if serial computerised testing is feasible for cognitive assessment in an acute post-stroke phase, measured by assessment completion rates.MethodAn observational cohort study recruited consecutive stroke patients admitted to an acute stroke unit within 48 hours of onset. Daily assessment with the Cambridge Neuropsychological Test Automated Battery (CANTAB) was performed for seven days, and single Montreal Cognitive Assessment (MoCA).ResultsSeventy-one participants were recruited, mean age 74 years, with 67 completing daily testing. Participants had predominantly mild (85%; NIHSS ≤6), ischemic (90%) stroke, 32% demonstrated clinical delirium. The first day of testing, 76% of participants completed CANTAB batteries. Eighty-seven percent of participants completed MoCA a mean of 3.4 days post-stroke. The proportion of CANTAB batteries completed improved significantly from day 2 to day 3 post-stroke with test completion rates stabilizing ≥ 92% by day 4. Participants with incomplete CANTAB were older, with persisting delirium, and longer stay in acute care.ConclusionSerial computerised cognitive assessments are feasible the first week post-stroke and provide a novel approach to measuring cognitive change for both clinical and research purposes. Maximum completion rates by day four have clinical implications for optimal timing of cognitive testing.     

Early cognitive impairment predicts long-term depressive symptoms and quality of life after stroke

OBJECTIVE: The aim of the present study was to examine the predictive value of cognitive impairment in the acute phase after stroke as a risk factor for long-term (six to ten months after stroke) depressive symptoms (DS) and a reduced quality of life (QOL), independent of demographic and neurological predictors. METHODS: We evaluated 143 patients within the first 3 weeks post-stroke. Predictor variables included domain-specific cognitive function, demographic data, vascular risk factors, lesion characteristics, and clinical factors. Predictor variables associated with long-term DS (Montgomery Asberg Depression Rating Scale >or=7) and QOL (Stroke-Specific Quality of Life Scale) were identified with multiple logistic and linear regression. RESULTS: Long-term DS were independently predicted by cognitive impairment at baseline, DS at baseline, female sex, diabetes mellitus, and previous TIA(s). Cognitive impairment, increasing age, and functional dependence predicted a reduced QOL, whereas hypercholesterolaemia predicted a better QOL. Among all cognitive disorders, unilateral neglect was the greatest risk factor for DS after 6 months, whereas a disorder in visual perception and construction affected QOL the most. CONCLUSIONS: Cognitive impairment and vascular risk factors are important predictors of long-term DS and QOL after stroke. The prognostic value of cognition suggests a reactive component in the development or continuation of long-term DS.     

Cognitive recovery trajectories 3 months following stroke in Mexican American and non-Hispanic white adults

ObjectivesWe examined whether cognitive trajectories from 0-3 months after stroke differ between Mexican Americans (MAs) and non-Hispanic white (NHW) adults.Materials and MethodsThe sample included 701 participants with ischemic stroke (62% MA; 38% NHW) from the population-based stroke surveillance study, the Brain Attack Surveillance in Corpus Christi (BASIC) Project, between 2008-2013. The outcome was the modified Mini Mental State Examination (3MSE, range 0-100 lower scores worse). Linear mixed effects models were utilized to examine the association between ethnicity and cognitive trajectories from 0-3 months following stroke, adjusting for confounders.ResultsMAs were younger, had lower educational attainment, and fewer had health insurance than NHWs (all p< 0.01). A smaller proportion of MAs were rated by informants as exhibiting pre-stroke cognitive decline than NHW (p < .0.05). After accounting for confounders, MAs demonstrated lower cognitive performance at post-stroke baseline and at 3-months following stroke (-2.00; 95% CI =-3.92, -0.07). Cognitive trajectories from 0-3 months following stroke were indicative of modest cognitive recovery (increase of 0.034/day, 95% CI =0.030-0.036) and did not differ between MAs and NHWs (p = 0.68).ConclusionWe found no evidence that cognitive trajectories in the first three months following stroke differed between MAs and NHWs. MAs demonstrated lower cognitive performance shortly after stroke and at three months following stroke compared to NHWs. Further research is needed to identify factors contributing to ethnic disparities in cognitive outcomes after stroke.     

The unsolved role of heightened connectivity from the unaffected hemisphere to paretic arm muscles in chronic stroke

ObjectiveIpsilateral connectivity from the non-stroke hemisphere to paretic arm muscles appears to play little role in functional recovery, which instead depends on contralateral connectivity from the stroke hemisphere. Yet the incidence of ipsilateral projections in stroke survivors is often reported to be higher than normal. We tested this directly using a sensitive measure of connectivity to proximal arm muscles.MethodTMS of the stroke and non-stroke motor cortex evoked responses in pre-activated triceps and deltoid muscles of 17 stroke survivors attending reaching training. Connectivity was defined as a clear MEP or a short-latency silent period in ongoing EMG in ≥ 50% of stimulations. We measured reaching accuracy at baseline, improvement after training and upper limb Fugl-Meyer (F-M) score.ResultsIncidence of ipsilateral connections to triceps (47%) and deltoid (58%) was high, but unrelated to baseline reaching accuracy and F-M scores. Instead, these were related to contralateral connectivity from the stroke hemisphere. Absolute but not proportional improvement after training was greater in patients with ipsilateral responses.ConclusionsDespite enhanced ipsilateral connectivity, arm function and learning was related most strongly to contralateral pathway integrity from the stroke hemisphere.SignificanceFurther work is needed to decipher the role of ipsilateral connections.     

Domain-specific cognitive recovery after first-ever stroke: a follow-up study of 111 cases.

The objective of this study is to examine the prognosis of acute cognitive disorders post-stroke, and to evaluate which clinical factors predict domain-specific cognitive recovery. We followed the course of cognitive functioning in 111 stroke patients and 77 healthy controls by administering two neuropsychological examinations with a 6 to 10 month interval (mean interval, 7.5 +/- 1.3 months). The baseline examination was administered within three weeks post-stroke (mean interval, 7.9 +/- 4.2 days). To examine determinants of domain-specific cognitive recovery, we recorded vascular risk factors, clinical variables, and lesion characteristics. Recovery in visual perception/construction (83%) and visual memory (78%) was the most common. An acute cognitive disorder predicted a long-term disorder in the same domain (all p < .05), except for visual perception/construction. Factors associated with poor cognitive recovery were age (all p < .01), preexistent verbal ability (all p < .005), lesion locations involving the temporal (all p < .05), frontal (p < .05) and occipital lobe (allp < .05), lesion volume (p < or = .001), and diabetes mellitus (p < .01). An early neuropsychological examination provides valuable information on long-term cognitive performance. The prognosis of higher-level visual disorders is the most favorable. Cognitive recovery is associated with age, preexistent ability, lesion volume, lesion location, and diabetes mellitus.     

Significance of longitudinal changes in the default‐mode network for cognitive recovery after stroke

Although a considerable number of patients suffer from cognitive impairments after stroke, the neural mechanism of cognitive recovery has not yet been clarified. Repeated resting‐state functional magnetic resonance imaging (fMRI) was used in this study to examine longitudinal changes in the default‐mode network (DMN) during the 6 months after stroke, and to investigate the relationship between DMN changes and cognitive recovery. Out of 24 initially recruited right‐hemispheric stroke patients, 11 (eight males, mean age 55.7 years) successfully completed the repeated fMRI protocol. Patients underwent three fMRI sessions at 1, 3 and 6 months after stroke. Their DMNs were analysed and compared with those of 11 age‐matched healthy subjects (nine males, mean age 56.2 years). Correlations between DMN connectivity and improvement of the cognitive performance scores were also assessed. The stroke patients were found to demonstrate markedly decreased DMN connectivity of the posterior cingulate cortex, precuneus, medial frontal gyrus and inferior parietal lobes at 1 month after stroke. At 3 months after stroke, the DMN connectivity of these brain areas was almost restored, suggesting that the period is critical for neural reorganization. The DMN connectivity of the dorsolateral prefrontal cortex in the contralesional hemisphere showed a significant correlation with cognitive function recovery in stroke patients, and should be considered a compensatory process for overcoming cognitive impairment due to brain lesion. This is the first longitudinal study to demonstrate the changes in DMN during recovery after stroke and the key regions influencing cognitive recovery.     

Stratifying chronic stroke patients based on the influence of contralesional motor cortices: An inter-hemispheric inhibition study

ObjectiveA recent “bimodal-balance recovery” model suggests that contralesional influence varies based on the amount of ipsilesional reserve: inhibitory when there is a large reserve, but supportive when there is a low reserve. Here, we investigated the relationships between contralesional influence (inter-hemispheric inhibition, IHI) and ipsilesional reserve (corticospinal damage/impairment), and also defined a criterion separating subgroups based on the relationships.MethodsTwenty-four patients underwent assessment of IHI using Transcranial Magnetic Stimulation (ipsilateral silent period method), motor impairment using Upper Extremity Fugl-Meyer (UEFM), and corticospinal damage using Diffusion Tensor Imaging and active motor threshold. Assessments of UEFM and IHI were repeated after 5-week rehabilitation (n = 21).ResultsRelationship between IHI and baseline UEFM was quadratic with criterion at UEFM 43 (95%conference interval: 40–46). Patients less impaired than UEFM = 43 showed stronger IHI with more impairment, whereas patients more impaired than UEFM = 43 showed lower IHI with more impairment. Of those made clinically-meaningful functional gains in rehabilitation (n = 14), more-impaired patients showed further IHI reduction.ConclusionsA criterion impairment-level can be derived to stratify patient-subgroups based on the bimodal influence of contralesional cortex. Contralesional influence also evolves differently across subgroups following rehabilitation.SignificanceThe criterion may be used to stratify patients to design targeted, precision treatments.     

Remote Ischemic Post-Conditioning may Improve Post-Stroke Cognitive Impairment: A Pilot Single Center Randomized Controlled Trial

Background and PurposeWe aimed to demonstrate the tolerability and feasibility and the effect of remote ischemic post-conditioning on cognitive functioning in patients with post-stroke cognitive impairment.MethodsThis was a single-center, randomized, outcome-blinded, placebo-controlled trial, randomized 1:1 to receive 4 cycles of remote ischemic post-conditioning or a sham procedure for 7 days. The primary outcome measure was tolerability and feasibility of remote ischemic post-conditioning. Secondary outcomes to measure the neurological function with national institute of health stroke scale and the cognitive impairment with Montreal Cognitive Assessment scale and Alzheimer's disease assessment scale-cognitive (at baseline, 90 days, 180 days).Results48 patients (24 RIPC and 24 Control) were recruited. remote ischemic post-conditioning was well tolerated with 90 out of 96 cycles completed in full. 4 patients experienced vascular events in the control group: 3 cerebrovascular and 1 cardiovascular event versus only 2 cerebrovascular events in the RIPC group. We showed the similar result in the neurological function with national institute of health stroke scale score with no statistically significant differences between RIPC and control group at baseline (P = 0.796) and 90 days (P = 0.401) and 180 days (P = 0.695). But compare with baseline, it was significantly difference in the control and RIPC group at 90 days (P < 0.05) and 180 days (P < 0.05). The comparison of Montreal Cognitive Assessment scale between two groups both showed that P > 0.05 at baseline which was no statistical difference, but P < 0.05 at 90 days and 180 days which were significant statistical difference. The comparison of Alzheimer's disease assessment scale-cognitive between two groups showed that P > 0.05 at baseline (P = 0.955) and 90 days (P = 0.138) was no statistical difference, but P = 0.005<0.05 at 180 days was significant statistical difference.ConclusionsThe remote ischemic post-conditioning for post-stroke cognitive impairment was well tolerated, safe and feasible. The remote ischemic post-conditioning may improve neurological and cognitive outcomes in patients with post-stroke cognitive impairment. A larger trial is warranted. (Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: ChiCTR1800015231.)     

Post-stroke cognitive impairment and the risk of stroke recurrence and death in patients with insulin resistance

ObjectivePost-stroke cognitive impairment (PSCI) is associated with etiology, severity, and functional outcome of stroke. The risks of recurrent stroke and death in patients with PSCI and insulin resistance (IR) is unknown. The goal of this study was to determine whether global and domain-specific cognitive impairment after stroke in patients with IR was associated with recurrent stroke and death.Materials and MethodsWe studied patients with recent stroke or transient ischemic attack (TIA) and IR with a baseline Modified Mini-Mental State Examination (3MS) cognitive exam at median of 79 days after stroke. We considered a baseline score of ≤ 88 on the 3MS to indicate global cognitive impairment, and domain-specific summary scores in the lowest quartile to indicate language, attention, orientation, memory and visuospatial impairments. The primary endpoint was fatal or non-fatal recurrent stroke, and the secondary endpoints were all-cause mortality, and fatal or non-fatal myocardial infarction (MI).ResultsAmong studied n = 3,338 patients 13.6% had global cognitive impairment. During the median 4.96 years of follow-up, 7.4% patients experienced recurrent stroke, 3.5% MI, and 7.3% died. In the fully adjusted model, impairment in language (HR 1.35; 95% CI 1.01—1.81) and orientation (HR 1.41; 95% CI: 1.06—1.87) were associated with a higher risk of recurrent stroke, while attention impairment was associated with all-cause mortality (HR 1.34; 95% CI: 1.01—1.78).Discussion/ConclusionIn patients with recent stroke/TIA and IR, post-stroke language and orientation impairments independently predicted recurrent stroke, while attention deficit was associated with increased risk of all-cause mortality.     

Longitudinal in vivo MRI of alterations in perilesional tissue after transient ischemic stroke in rats

Spontaneous restoration of function after stroke is associated with remodelling of functional neuronal networks in and around the ischemic lesion. However, the spatiotemporal profile of structural alterations in (peri)lesional tissue in relation to post-stroke recovery of neuronal function remains largely to be elucidated.We performed neurological testing in combination with in vivo serial T₂-weighted magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to assess functional recovery in relation to longitudinal changes in tissue integrity from 3 h up to 9 weeks after experimental unilateral stroke in rats (n = 7). Subsequently, to evaluate perilesional neuronal connectivity, we conducted manganese-enhanced MRI after MnCl₂ injection in cortical tissue at the boundary of the lesion at 10 weeks post-stroke (n = 5). All animals showed significant improvement of neurological function over time. Normalization of tissue T₂ and fractional diffusion anisotropy (FA) after significant subacute change was observed in cortical and subcortical lesion borderzones between 3 and 9 weeks post-stroke. Progressive FA increase above baseline levels was detected in perilesional white matter areas (n = 4). In these animals particularly, significant manganese enhancement appeared within the neuronal network around the chronic lesion, including areas that were part of the lesion at day 3 post-stroke. This longitudinal multi-parametric MRI study suggests that resolution of early ischemic damage and reorganization of white matter in perilesional tissue is chronically accompanied by preservation or restoration of neuronal connectivity, which may significantly contribute to post-stroke functional recovery.     

Recovery of submaximal upper limb force production is correlated with better arm position control and motor impairment early after a stroke

Objective

This study determined whether recovery of upper limb position control using submaximal force production correlates with an improvement in functional arm impairment during early recovery from stroke.

Methods

Ten consecutive inpatients were recruited from a stroke unit. Each patient was in early recovery (<8 weeks post-lesion) from their first ever stroke. Evaluations of submaximal continuous force production and position control, maximal force production at the shoulder and a clinical outcome measure of motor impairment (Fugl-Meyer score; FM) were performed 20 days post-stroke as a baseline and then once a week for the following four weeks.

Results

Submaximal force production and its modulation during a position-holding task improved in early recovery after stroke, whereas maximal force production did not. Better modulation of submaximal force production enabled improved arm position control which was significantly correlated to the changes in FM score of motor impairment during recovery.

Conclusions

This study demonstrated that improvement in submaximal force modulation can operate as a mechanism enabling better motor behaviour such as arm position control during early recovery from a stroke.

Significance

Future rehabilitation strategies may benefit from adding submaximal force development and modulation to early interventions after stroke.     

Leukoaraiosis Predicts Short-term Cognitive But not Motor Recovery in Ischemic Stroke Patients During Rehabilitation

Background: Leukoaraiosis has been shown to impact functional outcomes after acute ischemic stroke. However, its association with domain specific recovery after ischemic stroke is uncertain. We sought to determine whether pre-existing leukoaraiosis is associated with short-term motor and cognitive recovery after stroke. Methods: We retrospectively studied ischemic stroke patients admitted to acute inpatient rehabilitation (AIR) between January 2013 and September 2015. Patient baseline characteristics, infarct volume, prestroke modified Rankin Scale, stroke cause, rehabilitation length of stay, and Functional Independence Measure (FIM) scores were recorded. Leukoaraiosis severity was graded on brain magnetic resonance imaging using the Fazekas scale. Multiple linear regression was used to determine factors independently associated with the total, cognitive, and motor FIM scores at AIR discharge, respectively. Results: Of 1600 ischemic stroke patients screened, 109 patients were included in the final analysis. After adjustment, the initial National Institute of Health Stroke Scale (β ?0.541, confidence interval [CI] ?0.993 to ?0.888; P = 0.020) and pre-existing leukoaraiosis severity (β ?1.448, CI ?2.861 to ?0.034; P = 0.045) independently predicted the total FIM score. Domain specific analysis showed that infarct volume (β ?0.012, CI ?0.019 to ?0.005; P = 0.002) and leukoaraiosis severity (β ?0.822, CI ?1.223 to ?0.410; P = 0.0001) independently predicted FIM cognitive scores at discharge from AIR. Leukoaraiosis did not predict FIM motor score (P = 0.17). Conclusions: Leukoaraiosis severity is an independent predictor of total and cognitive, but not motor FIM scores after AIR for acute ischemic stroke. This highlights that leukoaraiosis affects poststroke recovery in a domain specific fashion, information that may aid counseling of patients and families as well as tailor rehabilitative efforts.