Predictors of cognitive functioning after carotid revascularization

Cerebral autoregulation, spreading depolarization, and implications for targeted therapy in brain injury and ischemia

Cerebral autoregulation is an intrinsic myogenic response of cerebral vasculature that allows for preservation of stable cerebral blood flow levels in response to changing systemic blood pressure. It is effective across a broad range of blood pressure levels through precapillary vasoconstriction and dilation. Autoregulation is difficult to directly measure and methods to indirectly ascertain cerebral autoregulation status inherently require certain assumptions. Patients with impaired cerebral autoregulation may be at risk of brain ischemia. One of the central mechanisms of ischemia in patients with metabolically compromised states is likely the triggering of spreading depolarization (SD) events and ultimately, terminal (or anoxic) depolarization. Cerebral autoregulation and SD are therefore linked when considering the risk of ischemia. In this scoping review, we will discuss the range of methods to measure cerebral autoregulation, their theoretical strengths and weaknesses, and the available clinical evidence to support their utility. We will then discuss the emerging link between impaired cerebral autoregulation and the occurrence of SD events. Such an approach offers the opportunity to better understand an individual patient's physiology and provide targeted treatments.

Long-term cognitive and neurovascular changes after carotid endarterectomy

BACKGROUND

Carotid endarterectomy (CEA) has been associated with both cognitive decline and improvement, but the underlying neurovascular mechanisms are unclear. The aim of this study was to investigate the relationship between neurovascular indices and cognitive changes after CEA.

METHODS

We studied 55 patients with severe (≥70%) symptomatic or asymptomatic carotid stenosis before and six months after CEA. A wide array of neuropsychological tests was arranged in eight cognitive domains and cognitive functions specific to hemisphere ipsilateral to operation. Differences in cognitive performance between patients and 38 matching healthy controls were studied with linear mixed models. Neurovascular functioning and microembolic signals were assessed with transcranial Doppler ultrasound of the middle cerebral artery. Associations between neurovascular indices and cognitive change were assessed with linear regression analyses.

RESULTS

On group level, the CEA patients improved more than controls in working memory, whereas no cognitive deterioration was detected. Also on individual level, improvement was most frequently observed in working memory. Worse preoperative cerebrovascular reactivity was related with improvement in cognitive functions of the ipsilateral hemisphere. Low preoperative pulsatility index was associated with improvement in executive functioning and ipsilateral cognitive functions. Poorer preoperative blood flow velocity associated with improvement in complex attention. Microembolic signals were rare.

CONCLUSION

The present findings suggest that CEA may have beneficial long-term effects on cognition. These effects may specifically involve patients with impaired preoperative circulatory adaptive mechanisms.

Short-term blood pressure variability and brain functional network connectivity in older adults

Background

Blood pressure variability is increasingly linked with cerebrovascular disease and Alzheimer's disease, independent of mean blood pressure levels. Elevated blood pressure variability is also associated with attenuated cerebrovascular reactivity, which may have implications for functional hyperemia underpinning brain network connectivity. It remains unclear whether blood pressure variability is related to functional network connectivity. We examined relationships between beat-to-beat blood pressure variability and functional connectivity in brain networks vulnerable to aging and Alzheimer's disease.

Methods

53 community-dwelling older adults (mean [SD] age = 69.9 [7.5] years, 62.3% female) without history of dementia or clinical stroke underwent continuous blood pressure monitoring and resting state fMRI scan. Blood pressure variability was calculated as variability independent of mean. Functional connectivity was determined by resting state fMRI for several brain networks: default, salience, dorsal attention, fronto-parietal, and language. Multiple linear regression examined relationships between short-term blood pressure variability and functional network connectivity.

Results

Elevated short-term blood pressure variability was associated with lower functional connectivity in the default network (systolic: standardized ß = -0.30 [95% CI -0.59, -0.01], p = .04). There were no significant associations between blood pressure variability and connectivity in other functional networks or between mean blood pressure and functional connectivity in any network.

Discussion

Older adults with elevated short-term blood pressure variability exhibit lower resting state functional connectivity in the default network. Findings support the role of blood pressure variability in neurovascular dysfunction and Alzheimer's disease. Blood pressure variability may represent an understudied early vascular risk factor for neurovascular dysfunction relevant to Alzheimer's disease, with potential therapeutic implications.

Why do guidelines recommend screening for abdominal aortic aneurysms, but not for asymptomatic carotid stenosis? A plea for a randomized controlled trial

BACKGROUND

Current guidelines do not recommend screening for asymptomatic carotid artery stenosis (AsxCS). The rationale behind this recommendation is that detection of AsxCS may lead to an unnecessary carotid intervention. In contrast, screening for abdominal aortic aneurysms is strongly recommended.

METHODS

A critical analysis of the literature was performed to evaluate the implications of detecting AsxCS.

RESULTS

Patients with AsxCS are at high risk for future stroke, myocardial infarction and vascular death. Population-wide screening for AsxCS should not be recommended. Additionally, screening of high-risk individuals for AsxCS with the purpose of identifying candidates for a carotid intervention is inappropriate. Instead, selective screening for AsxCS should be considered and should be viewed as an opportunity to identify individuals at high risk for atherosclerotic cardiovascular disease and future cardiovascular events for the timely initiation of intensive medical therapy and risk factor modification.

CONCLUSIONS

Although mass screening should not be recommended, there are several arguments suggesting that selective screening for AsxCS should be considered. The rationale supporting such selective screening is to optimize risk factor control and to initiate intensive medical therapy for prevention of future cardiovascular events, rather than to identify candidates for an intervention.

Volumetric Flow Assessment in Extracranial Arteries in Patients with 70-99% Internal Carotid Artery Stenosis

Background: Cerebral blood flow (CBF) can be related to the risk of occurrence of neurological symptoms. Well-developed collateral circulation is a good prognostic factor in patients with cerebrovascular disease. Understanding the mechanisms of collateral circulation may be important in the diagnosis, treatment, and monitoring in this group of patients. The aim of this study covered the assessment of CBF in patients with 70−99% Internal carotid artery (ICA) stenosis, focusing on the circulation pathways and flow volume in extracranial arteries. Materials and methods: 53 patients with 70−99% ICA stenosis (mean age 73.4 ± 7 years old; 17 female, mean age 73.9 ± 7.5 years old; 36 male, mean age 73.2 ± 6.8 years old) were included in the study. In all patients a Doppler ultrasound (DUS) examination, measuring blood flow volume in the internal carotid artery (ICA), external carotid artery (ECA), and vertebral artery (VA), was performed. The cerebral blood flow (CBF) was compared to the previously reported CBF values in the healthy population > 65 years old. Results: Among the study groups three subgroups with flow differences were identified: patients with elevated CBF (significant volumetric flow compensation—26/53, 49%), patients with CBF similar to (mild compensation—17/53, 32%), and patients with CBF lower than (no compensation—10/53, 19%) the healthy, equally aged population. The percentage of patients with significant volumetric flow compensation was the highest in age groups 65−69 years old (62.5%) and >80 years old (60%). In the oldest age group (>80 years old) no patients without flow compensation (0%) were observed. The level of compensation depends on the number of the arteries with compensatory increased flow. In patients with significant volumetric flow compensation, the compensatory increased flow was observed, on average, in 3.31 arteries, in the mild compensation group—in 2.18 arteries, and in the no compensation group only in 1 artery. ICA plays the most important role in the volumetric flow compensation—the increase in the flow volume, in comparison to the reference values, was between 116.7 mL/min and 251.9 mL/min (in the ECA 57.6 mL/min−110.4 mL/min; in the VA 73.9 mL/min−104.9 mL/min). The relative flow increase was highest in the VA: 215−246%, then in the ECA: 163−206%, and finally in the ICA: 148.6−192%. The increased flow was most commonly observed in the VA—57 arteries, in second place in the ECA—42 arteries, and ICA—31 arteries. In patients with unilateral ICA stenosis, the volumetric flow increase was stated more frequently in the ipsilateral ECAs then in the contralateral ones (23 vs. 14). In the VA the opposite tendency was observed (29 contralateral vs. 23 ipsilateral). The ability of volumetric flow compensation decreased significantly with increasing age. Conclusions: Understanding the mechanisms of collateral circulation and their assessment in Doppler ultrasonography may provide a novel and easily accessible tool of identifying and monitoring patients with cerebrovascular disease.

Volumetric Flow Assessment in Doppler Ultrasonography in Risk Stratification of Patients with Internal Carotid Stenosis and Occlusion

(1) Background: Alterations of blood flow volume in extracranial arteries may be related to the risk of occurrence of neurological symptoms. The aim of this study was the estimation of cerebral blood flow (CBF) in Doppler ultrasonography, as well as comparison of the flow volume in asymptomatic patients over 65 years old with ≥50%, and symptomatic patients with ≥70% internal carotid artery (ICA) stenosis, in order to assess whether the changes in the CBF correlates with the presence of neurological symptoms. (2) Methods: 308 patients over 65 years old were included in the retrospective cohort observational study: 154 asymptomatic with ≥50% ICA stenosis, 123 healthy volunteers, and 31 symptomatic referred for surgical treatment. The study group was split according to ICA stenosis (50–69%, 70–99% and occlusion). In all patients an extensive Doppler ultrasound examination with measurements of flow volume in common, internal, external carotid (ECA) and vertebral arteries (VA) was performed. (3) Results: Among asymptomatic (A) and symptomatic (S) patients with carotid stenosis 3 subgroups were identified: 57/154—37% (A) and 8/31—25.5% (S)—with significantly increased flow volume (CBF higher than reference range: average CBF + std. dev in the group of healthy volunteers), 67/154—43.5% (A) and 12/31—39% (S)—with similar to reference group flow volume (CBF within range average ± std.dev), and 30/154—19.5% (A) and 11/31—35.5% (S)—with decreased flow volume in extracranial arteries (flow lower than average-std.dev. in healthy volunteers). In symptomatic patients the percentage of patients with significant compensatory increased flow tends to raise with the severity of the stenosis, while simultaneous decline of number of patients with mild compensation (unchanged total CBF) is observed. The percentage of patients without compensation remains unchanged. In the group referred for surgical treatment (symptomatic, ≥70% ICA stenosis) the percentage of patients with flow compensation is twice as low as in the asymptomatic ones with similar degree of the ICA stenosis (8/31—25.8% vs. 26/53—49%, p = 0.04). Compensatory elevated flow was observed most frequently in ECA. (4) Conclusions: The presence of significant volumetric flow compensation has protective influence on developing ischaemic symptoms, including TIA or stroke. The assessment of cerebral inflow in Doppler ultrasonography may provide novel and easily accessible tool of identifying patients prone to cerebral ischaemia. The multivessel character of compensation with enhanced role of ECA justifies the importance of including this artery in the estimation of CBF.

Gray matter asymmetry in asymptomatic carotid stenosis

Even clinically “asymptomatic” carotid stenosis is associated with multidomain cognitive impairment, gray matter (GM) atrophy, and silent lesion. However, the links between them remain unclear. Using structural MRI data, we examined GM asymmetry index (AI) and white matter hyperintensity (WMH) in 24 patients with severe asymptomatic carotid stenosis (SACS), 24 comorbidity‐matched controls, and independent samples of 84 elderly controls and 22 young adults. As compared to controls, SACS patients showed worse verbal memories, higher WMH burden, and right‐lateralized GM in posterior middle temporal and mouth‐somatomotor regions. These clusters extended to pars triangularis, lateral temporal, and cerebellar regions, when compared with young adults. Further, a full‐path of WMH burden (X), GM volume (atrophy, M1), AI (asymmetry, M2), and neuropsychological variables (Y) through a serial mediation model was analyzed. This analysis identified that left‐dominated GM atrophy and right‐lateralized asymmetry in the posterior middle temporal cortex mediated the relationship between WMH burden and recall memory in SACS patients. These results suggest that the unbalanced hemispheric atrophy in the posterior middle temporal cortex is crucial to mediating relationship between WMH burden and verbal recall memories, which may underlie accelerated aging and cognitive deterioration in patients with SACS and other vascular cognitive impairment.

Carotid revascularization and cognitive impairment: the neglected role of cerebral small vessel disease

Carotid atherosclerosis is a pathological process that leads to narrowing of the vessel lumen and a consequent risk of stroke. Revascularization procedures such as carotid endarterectomy (CEA) and carotid stenting aim to reduce occurrence of stroke in selected patients. Due to the proven benefit and low intraoperative risk, CEA is currently the preferred choice in candidates for carotid revascularization. However, the risk of cognitive impairment subsequent to CEA has not been fully elucidated and is unclear whether certain conditions, such as frailty, may increase this risk. There is consistent evidence that shows that frail patients have higher risk of cognitive impairment after surgical procedure. Moreover, brain pre-existing conditions may play a role in cognitive impairment after CEA. Cerebral small vessel disease (SVD) is a pathology that involves microcirculation and is detectable with computed tomography or magnetic resonance. SVD shares common vascular risk factors with carotid atherosclerosis, is a major contributor to vascular cognitive impairment and vascular dementia, and has been proposed as a marker of brain frailty. In this review, we discuss the current evidence about the link between carotid revascularization and cognitive impairment and advance the hypothesis that SVD may play a relevant role in development of cognitive impairment after carotid revascularization.

Relationship of Neutrophil-to-Lymphocyte Ratio with Carotid Plaque Vulnerability and Occurrence of Vulnerable Carotid Plaque in Patients with Acute Ischemic Stroke

Background

Carotid plaque is an undefined risk factor in ischemic stroke and is driven by inflammation. Mounting evidence suggests that neutrophil-to-lymphocyte ratio (NLR) is crucial not only for cerebrovascular events but also in atherosclerosis progression. Here, we aimed to explore the association between the admission NLR and carotid plaque vulnerability as well as the occurrence of vulnerable carotid plaque detected by carotid ultrasonography in patients with acute ischemic stroke (AIS) among Chinese.

Methods

We conducted a retrospective study composed of 588 patients with AIS and 309 healthy controls free of carotid plaque in the Department of Neurology in The Second Hospital of Lanzhou University from March 2014 to February 2015. All patients were classified as nonplaque, stable plaque, and vulnerable plaque groups on the basis of carotid ultrasonography results. The baseline information was collected and compared among the four different groups. The correlation between variables and carotid plaque vulnerability was tested by Spearman linear correlation analysis. To identify the independent predictors for vulnerable carotid plaque, univariate and multivariate logistic regression analysis was performed.

Results

The comparisons of age, sex proportion, history of hypertension, diabetes, and smoking, the levels of HDL-C, Lp(a), BMI, SBP, DBP, Fib, CRP, leukocyte, and NLR among the four groups showed a statistically significant difference (P < 0.05); in particular, the NLR was significantly higher in the vulnerable plaque group as compared to the control (P = 0.043), nonplaque (P = 0.022), and stable plaque groups (P = 0.015). The Spearman correlation analysis presented a positive correlation between carotid plaque vulnerability and age (r = 0.302; P < 0.001), SBP (r = 0.163; P < 0.001), and NLR (r = 0.087; P = 0.034), while the lymphocyte was negatively related to the carotid plaque vulnerability (r = −0.089; P = 0.030). The multivariate logistic regression analysis adjusted for confounding factors revealed that age (odds ratio [OR], 1.042; 95% confidence interval [CI], 1.025-1.060; P < 0.001), male gender (OR, 2.005; 95% CI, 1.394-2.884; P < 0.001), diabetes (OR, 1.481; 95% CI, 1.021-2.149; P = 0.039), SBP (OR, 1.012; 95% CI, 1.003-1.021; P = 0.010), and NLR (OR, 1.098; 95% CI, 1.018-1.184; P = 0.015) are independent predictors of vulnerable carotid plaque in patients with AIS.

Conclusion

The admission NLR is a novel and meaningful biomarker that can be used in predicting carotid plaque vulnerability and the presence of vulnerable carotid plaque assessed by carotid ultrasonography in patients with AIS among Chinese.

Surface-based Cortical Morphometry, White Matter Hyperintensity, and Multidomain Cognitive Performance in Asymptomatic Carotid Stenosis

Carotid stenosis is a major contributor to vascular dementia. Recent studies suggest that even clinically "asymptomatic" carotid stenosis is linked with cognitive decline and neuroimaging changes. Here we examined surface-based cortical morphometry, white matter hyperintensity (WMH), and multidomain cognitive performance in unilateral severe (>70% narrowing) asymptomatic carotid stenosis (SACS). We included 24 SACS patients (19 males/5 females; 64.25 ± 7.18 years) and 24 comorbidities-matched controls (19 males/5 females; 67.16 ± 6.10 years), and measured cortical thickness, sulcal depth, gyrification, cortical complexity, and WMH loads with structural MRI images. The SACS patients exhibited: (1) thinner cortex in bilateral somatosensory/motor, bilateral inferior frontal, bilateral fusiform, and left lateral temporal areas; (2) shallower sulci in left lateral temporal, parietal, insular and somatosensory/motor areas; (3) both hyper- and hypo-gyrification in lateral temporal and frontal cortices; (4) lower complexity (fractal dimension) in left insular and right superior temporal areas. Further association analyses showed that the cortical alterations were significantly correlated with verbal memory and WMH burden in SACS. These results suggest that SACS patients present a left-dominated damage tendency, especially in the Perisylvian cortices that span across several large-scale systems of somatosensory/motor and language. Our findings also provide cortical anatomy evidence for cognitive impairment in SACS, suggesting a neuroanatomical predisposition to dementia and cerebrovascular events.

Effects of Carotid Artery Stent and Carotid Endarterectomy on Cognitive Function in Patients with Carotid Stenosis

BACKGROUND

Carotid artery stenosis is closely related to cognitive dysfunction, in which decreased cerebral perfusion is one of the important factors. Both carotid artery stent implantation and carotid endarterectomy can relieve stenosis and increase cerebral perfusion. In this study, we aimed to compare the effects of carotid artery stent implantation and endarterectomy on cognitive function.

METHODS

A total of 98 patients with carotid artery stenosis hospitalized in our hospital from July 2015 to January 2017 were included. Among them, 50 cases underwent carotid artery stent implantation treatment as stent implantation group (CAS group), and 48 cases underwent carotid artery endarterectomy treatment as carotid endarterectomy group (CEA group). Using the Mini-Mental State Examination Scale (MMSE Scale) and the Montreal Cognitive Assessment Scale (MoCA Scale), the cognitive function scores of the two groups of patients before and after 3 and 6 months of operation were measured, and the patients were also measured before and after surgery, after the serum NSE, hs-CRP content.

RESULTS

The serum NSE, hs-CRP content, MMSE score, and MoCA score of the two groups before treatment were not statistically significant (P > 0.05). The MMSE score and MoCA score of the two groups of patients before treatment were lower than the normal value, suggesting carotid artery stenosis combined with different degrees of cognitive dysfunction. Carotid artery stenosis is different, and patients' cognitive function is also different. The MMSE score and MoCA score of the two groups at 3 and 6 months after operation were higher than before treatment, and there was a statistically significant difference between 6 and 3 months after operation (P < 0.05), but at each time There was no statistically significant difference between the two groups (P > 0.05). The NSE content of the two groups of patients after operation decreased compared with that before treatment, and the decrease in 6 months after operation was more obvious than that in March (P < 0.05). However, the difference between the two groups at each time point was not statistically significant (P > 0.05). The content of hs-CRP in the two groups of patients was higher than that before the operation, and the CAS group was significantly higher than the CEA group; the difference was statistically significant (P < 0.05).

CONCLUSION

Carotid artery stent and carotid endarterectomy are effective in improving the cognitive function of patients with carotid stenosis, but there is no significant difference between the two.

Endovascular treatment and cognitive outcome after anterior circulation ischemic stroke

The impact of reperfusion therapies on cognition has been poorly explored and little knowledge exists. We explored the influence of endovascular treatment (EVT) on cognitive outcome in patients with anterior circulation ischemic stroke. Patients presenting with ischemic stroke due to anterior large vessel occlusion who underwent intravenous thrombolysis (IVT) alone or EVT plus IVT were recruited. Cognitive abilities were evaluated at 6 months from stroke through a neuropsychological test battery. A total of 88 patients with a mean age of 66.3 ± 12.9 years were included, of which 38 treated with IVT alone and 50 with IVT plus EVT. Compared to patients treated with IVT alone, patients who received EVT plus IVT performed significantly better at the neuropsychological tests exploring executive functions, attention, abstract reasoning, visuospatial ability, visual and verbal and memory. At multivariable regression analysis, the EVT was independently associated with the 6-month cognitive performance after the adjustment for age, sex, admission National Institutes of Health Stroke Scale score, systolic blood pressure, glucose level, Alberta Stroke Program Early CT score, side of stroke, site of occlusion, and Back Depression Inventory score [Stroop Test Word Reading: _adjβ = 13.99, 95% confidence interval (CI) 8.47–19.50, p < 0.001; Stroop Test Colour Naming: _adjβ = 6.63, 95% CI 2.46–10.81, p = 0.002; Trail Making Test-A: _adjβ = − 92.98, 95% CI − 153.76 to − 32.20, p = 0.003; Trail Making Test-B: _adjβ = − 181.12, 95% CI − 266.09 to − 96.15; p < 0.001; Digit Span Test Forward: _adjβ = 1.44, 95% CI 0.77–2.10, p < 0.001; Digit Span Test Backward: _adjβ = 1.10, 95% CI 0.42–1.77, p = 0.002; Coloured Progressive Matrices: _adjβ = 5.82, 95% CI 2.71–8.93, p < 0.001; Rey Complex Figure Test-Copy: _adjβ = 6.02, 95% CI 2.74–9.30, p < 0.001; Rey Complex Figure Test-Immediate recall: _adjβ = 6.00, 95% CI 2.34–9.66, p = 0.002; Rey Complex Figure Test-Delayed recall: _adjβ = 5.73, 95% CI 1.95–9.51, p = 0.003; Rey Auditory Verbal Learning Test-Immediate recall: _adjβ = 12.60, 95% CI 6.69–18.52, p < 0.001; Rey Auditory Verbal Learning Test-Delayed recall: _adjβ = 1.85, 95% CI 0.24–3.45, p = 0.025]. Patients treated with EVT plus IVT had better cognitive performance than patients treated with IVT alone at 6 months from anterior circulation ischemic stroke.

Effects of Endovascular Stent-Assisted Angioplasty on Cellular Metabolism in the Hippocampus of Elderly Patients with Symptomatic Vertebrobasilar Artery Stenosis

BACKGROUND Cerebral artery stenosis is closely related to cognitive function, and angioplasty can improve the cognitive function of elderly patients with vertebrobasilar artery stenosis. The specific mechanism, however, is not clear. This study explored the effect of angioplasty on cellular metabolism in the hippocampus of elderly patients with symptomatic vertebrobasilar artery stenosis. MATERIAL AND METHODS Eighteen elderly patients with symptomatic vertebrobasilar artery stenosis who underwent endovascular stent-assisted angioplasty (ESAA) in our department were studied. The changes in cellular metabolism (NAA / Cr, CHO / Cr, NAA / CHO) in bilateral hippocampal areas were detected by MRS before and at 6 months and 12 months after the ESAA. The Montreal Cognitive Assessment Scale (MoCA), Hamilton Depression Self-assessment Scale (HAMD), and Hamilton Anxiety Self-assessment Scale (HAMA) were also used to evaluate the cognition, depression, and anxiety of patients at different time points of the study, and analyzed the correlation between the changes of cellular metabolism in the hippocampus and the scores of MoCA, HAMD, and HAMA. RESULTS The levels of NAA/Cr in left/right hippocampal areas were significantly higher at 6 and 12 months after the ESAA than before (1.01±0.17/1.22±0.26 vs. 1.10±0.20/1.05±0.26 vs. 0.82±0.10/0.84±0.11, respectively) (P<0.01). MoCA scores were positively correlated with the levels of NAA/Cr in the left/right hippocampal areas (P<0.05 and P<0.01, respectively). CONCLUSIONS ESAA can improve cognitive function of patients by changing the cellular metabolism of the hippocampus in elderly patients with symptomatic vertebrobasilar artery stenosis.

Predicting Functional Outcome Based on Linked Data After Acute Ischemic Stroke: S-SMART Score

Prediction of outcome after stroke may help clinicians provide effective management and plan long-term care. We aimed to develop and validate a score for predicting good functional outcome available for hospitals after ischemic stroke using linked data. A total of 22,005 patients with acute ischemic stroke from the Clinical Research Center for Stroke Registry between July 2007 and December 2014 were included in the derivation group. We assessed functional outcomes using a modified Rankin scale (mRS) score at 3 months after ischemic stroke. We identified predictors related to good 3-month outcome (mRS score ≤ 2) and developed a score. External validations (geographic and temporal validations) of the developed model were performed. The prediction model performance was assessed using the area under the receiver operating characteristic curve (AUC) and the calibration test. Stroke severity, sex, stroke mechanism, age, pre-stroke mRS, and thrombolysis/thrombectomy treatment were identified as predictors for 3-month good functional outcomes in the S-SMART score (total 34 points). Patients with higher S-SMART scores had an increased likelihood of a good outcome. The AUC of the prediction score was 0.805 (0.798-0.811) in the derivation group and 0.812 (0.795-0.830) in the geographic validation group for good functional outcome. The AUC of the model was 0.812 (0.771-0.854) for the temporal validation group. Moreover, they had good calibration. The S-SMART score is a valid and useful tool to predict good functional outcome following ischemic stroke. This prediction model may assist in the estimation of outcomes to determine care plans after stroke.

Machine-learning prediction of self-care activity by grip strengths of both hands in poststroke hemiplegia

To investigate the relationships between grip strengths and self-care activities in stroke patients using a non-linear support vector machine (SVM).Overall, 177 inpatients with poststroke hemiparesis were enrolled. Their grip strengths were measured using the Jamar dynamometer on the first day of rehabilitation training. Self-care activities were assessed by therapists using Functional Independence Measure (FIM), including items for eating, grooming, dressing the upper body, dressing the lower body, and bathing at the time of discharge. When each FIM item score was ≥6 points, the subject was considered independent. One thousand bootstrap grip strength datasets for each independence and dependence in self-care activities were generated from the actual grip strength. Thereafter, we randomly assigned the total bootstrap datasets to 90% training and 10% testing datasets and inputted the bootstrap training data into a non-linear SVM. After training, we used the SVM algorithm to predict a testing dataset for cross-validation. This validation procedure was repeated 10 times.The SVM with grip strengths more accurately predicted independence or dependence in self-care activities than the chance level (mean ± standard deviation of accuracy rate: eating, 0.71 ± 0.04, P < .0001; grooming, 0.77 ± 0.03, P < .0001; upper-body dressing, 0.75 ± 0.03, P < .0001; lower-body dressing, 0.72 ± 0.05, P < .0001; bathing, 0.68 ± 0.03, P < .0001).Non-linear SVM based on grip strengths can prospectively predict self-care activities.