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1.

Objective

Diffusion-weighted imaging (DWI) infarct patterns can play a useful role in the management of ischemic stroke patients, particularly in identifying index stroke mechanisms. Novel vascular risk factors like high sensitivity C-reactive protein (hs-CRP) and the metabolic syndrome have recently been shown to be of prognostic importance following ischemic stroke. We aimed to determine the relationship between these novel factors and infarct patterns noted on DWI.

Methods

A total of 886 patients with acute cerebral infarcts within the MCA territory were prospectively studied. Using the DWI data the patients were divided into four groups: cortical, small (<1 cm) superficial, border-zone, and deep infarcts patterns. The independent associations of various infarct DWI patterns vs. hs-CRP and presence of the metabolic syndrome were evaluated after adjusting for the confounders.

Results

hs-CRP was highest among patients with cortical infarcts, while the metabolic syndrome was most frequent in patients with border-zone infarcts. Compared to the lowest quartile of hs-CRP level, those in the highest quartile were more likely to have the cortical pattern (OR, 3.55; 95% CI, 1.92–6.56; P < 0.001), and less likely to have the deep infarct pattern (OR, 0.49; 95% CI, 0.29–0.81; P = 0.006) in logistic regression analyses. There was an independent association between presence of the metabolic syndrome and the border-zone pattern (OR, 1.75; 95% CI, 1.12–2.73; P = 0.013).

Conclusions

hs-CRP levels and metabolic derangements are independently associated with infarct pattern in acute ischemic stroke, and may be the potential targets for lessening the clinical impact of certain infarct patterns.  相似文献   

2.

Background and purpose

Impaired autonomic function is common in the acute poststroke phase but little is known about its effects on functional outcome after acute ischemic stroke. This study sought to investigate the impact of autonomic dysfunction by Ewing's classification on functional outcome 2 months after acute ischemic stroke.

Methods

34 consecutive acute ischemic stroke patients within 7 days after onset were enrolled. On admission, autonomic function was assessed by Ewing's battery tests. Stroke severity was assessed by the National Institutes of Health Stroke Scale (NIHSS), autonomy in activities of daily living by the Barthel Index (BI), and global disability by the modified Rankin Scale (mRS). BI and mRS were also evaluated 2 months after ischemic stroke onset.

Results

On admission, eight patients were diagnosed as minor autonomic dysfunction and 26 patients as relatively severe autonomic dysfunction. The prevalence of relatively severe autonomic dysfunction in ischemic stroke patients was 76.5%. There were no significant differences in baseline characteristics between the minor and severe autonomic dysfunction groups. 2 months after stroke onset, the mean BI score of patients with minor autonomic dysfunction and severe autonomic dysfunction increased from 76.3 ± 15.3 on admission to 95.0 ± 7.1, 66.5 ± 15.2 on admission to 74.8 ± 15.9 respectively. The mean BI score after 2-month stroke onset and the change in BI from admission to 2-month outcome (delta BI) in patients with severe autonomic dysfunction were lower than those in patients with minor autonomic dysfunction (all P < 0.05).

Conclusions

Autonomic dysfunction occurs in acute stroke patients. Relatively severe autonomic dysfunction is related to an unfavorable functional outcome in patients with acute ischemic stroke.  相似文献   

3.

Background

Limited data exists about the role of Chlamydia pneumoniae elderly patients with acute ischemic stroke.

Objective

To study the role of C. pneumoniae in elderly patients (age more than 65 years) with acute ischemic stroke and its impact on stroke out come.

Methods

We recruited 100 elderly patients with acute ischemic stroke and 100 age and sex matched controls over a period of 2 years. IgG and IgA anti C. pneumoniae antibodies were measured by microimmunofluorescence technique in patients and controls. Good outcome was defined as a Modified Rankin score (mRS) of ≤2.

Results

We found C. pneumoniae antibodies in 35% stroke patients and in 18% control subjects (p = 0.01). Good out come at 90 days follow up was found in 20/35(57.1%) seropositive stroke patients compared to 37/65(56.9%) seronegative stroke patients (p = 0.9).

Conclusions

C. pneumoniae antibody positivity was independently associated with ischemic stroke in elderly patients and its presence does not alter the stroke outcome.  相似文献   

4.

Objectives

Increased common carotid artery intima-media thickness (CCA-IMT) is a risk factor for ischemic stroke and especially large vessel atherothrombotic infarction. However, the potential association of stroke severity with the intima-media thickening has not been previously studied. We sought to investigate the association between CCA-IMT and clinical severity of ischemic stroke in patients with symptomatic extracranial carotid artery stenosis (SCAS).

Patients and methods

Consecutive patients with acute, first-ever ischemic stroke and SCAS (50%–99%) were prospectively evaluated. All subjects underwent IMT measurements at the far wall of CCA. Stroke severity was assessed using the National Institute of Health Stroke Scale (NIHSS) on hospital admission and Barthel Ambulatory Index (BI) at hospital discharge.

Results

CCA-IMT was strongly correlated to NIH (Spearman's correlation coefficient: r = 0.546, p < 0.001) and BI (r = −0.450, p < 0.001) in the study population (n = 102). A 0.1 mm increase in CCA-IMT was independently associated with increasing NIHSS-scores on hospital admission (β: 0.510; p < 0.001) and decreasing BI-scores at hospital discharge (β: −0.483; p < 0.001) even after adjustment for demographic characteristics and cardiovascular risk factors. After including baseline stroke severity (NIHSS) in the multivariate linear regressions models evaluating early functional outcome, only NIHSS was independently related to BI (standardized linear regression coefficient: −0.776, p < 0.001), while the initial association between IMT and BI did not retain its statistical significance (β: −0.074, p = 0.276).

Conclusions

Increased CCA-IMT is independently associated with more severe stroke on admission in patients with SCAS.  相似文献   

5.

Objective

This study examined whether the manganese superoxide dismutase (MnSOD) gene Ala–9Val single-nucleotide polymorphism (SNP) is associated with neuroleptic-induced tardive dyskinesia (TD) and the severity of the abnormal involuntary movements in Korean schizophrenic patients.

Method

We investigated whether the MnSOD gene Ala–9Val SNP is associated with TD in Korean schizophrenic patients with (n = 83) and without (n = 126) TD who were matched for exposure to antipsychotics and other relevant variables.

Results

Logistic regression analysis revealed that being older (p = 0.026) was a risk factor for TD, but that there was no significant association between MnSOD gene and TD. Abnormal involuntary movements were more severe in carriers of the Ala allele than in noncarriers (p = 0.044).

Conclusion

These findings do not support that the MnSOD gene Ala–9Val SNP is associated with TD in Korean schizophrenic patients. However, this polymorphism might be related to the severity of abnormal involuntary movements in this population.  相似文献   

6.

Objectives

The aim of the current study was to design a new simpler form of National Institutes of Health Stroke Scale (NIHSS) for use in emergency settings, and compare its predictive ability with original NIHSS score for mortality.

Methods

A total of 152 consecutive patients with first ever ischemic stroke admitted to a university affiliated hospital were recruited. NIHSS score on admission was estimated and the predictive ability of NIHSS items for mortality at 28 days was evaluated by logistic regression. Stepwise discriminant analysis was performed on NIHSS items to obtain a discriminant function with the best discriminative ability for mortality. Further, receiver operating characteristics (ROC) curves were depicted to compare the new determined discriminant function with the original NIHSS score.

Results

Cumulative rate of mortality was 11.8% for 28-day follow-up period. Among NIHSS items, scores of visual field, limb ataxia and extinction neglect were not associated with mortality (P > 0.05). On the contrary, level of consciousness-commands, language and gaze were determined as independent indicators of mortality (P < 0.05), and their coefficients on discriminant function were equal to 0.65, 0.44 and 0.30, respectively. In addition, area under the ROC curve of the calculated discriminant function was not statistically different from NIHSS score (P > 0.05).

Conclusions

The suggested discriminant function, comprising NIHSS items of level of consciousness-commands, language and gaze, can predict 28-day mortality after ischemic stroke in a similar way to the original NIHSS score and can provide a baseline for stroke severity in emergency settings.  相似文献   

7.

Objective

This study examined how handrail location predictability affects perturbation-evoked arm responses in young and older adults and whether age-related changes in perturbation-evoked arm responses are specific to mechanisms associated with reactive postural control.

Methods

Young and older adults reached for a handrail in response to a support surface translation (perturbation-evoked) or to a visual cue (voluntary). For both movement tasks, the handrail location was made predictable or unpredictable to the participant. Electromyographic (EMG) activity and kinematics of the reaching arm were recorded to quantify the arm response.

Results

Posterior deltoid EMG activity during perturbation-evoked and voluntary movements were delayed by 15–74 ms (p < 0.001) and 16% smaller (p = 0.024) when the handrail was in an unpredictable compared to a predictable location. While ageing resulted in a 12–16 ms delayed initiation of EMG activity during perturbation-evoked reaching (p = 0.003), the effects of handrail predictability and movement task did not interact with age.

Conclusions

Age-related differences in perturbation-evoked arm responses are independent of both handrail location predictability and movement task.

Significance

Age-related differences in perturbation-evoked arm responses cannot be solely attributed to declines in reactive postural control. Rather, ageing leads to a deterioration of neural mechanisms common to both perturbation-evoked and voluntary arm movements.  相似文献   

8.

Background

Although cigarette smoking has been established as an important risk factor for stroke, the effect on the atherosclerotic stenosis, which are based on observational studies, have been controversial. We set out to examine the differences in the risk factors between smokers and nonsmokers and to investigate the association of cigarette smoking with cerebral arterial stenosis.

Methods

A total of 989 consecutive patients with acute noncardioembolic ischemic stroke were prospectively enrolled from June 2004 to January 2010. The risk factor profiles were compared between smokers and nonsmokers. We analyzed the degree of stenosis in all MRA, and evaluated influencing factors in the patients with intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS) who were randomly matched by age and sex.

Results

There were differences in the distribution of risk factors between the 467 (70.0%) nonsmokers and the 215 (30.0%) smokers. Nonsmokers were older (71.7 ± 11.0 versus 61.7 ± 12.0, p < 0.001) and had a higher frequency of hypertension than smokers had (75.4% versus 64.0%, p = 0.002). When smokers and nonsmokers were age- and sex-matched, smoking was more prevalent in patients with ICAS than with ECAS (32.9% versus 28.2%). Conditional regression analysis revealed that smoking and hypertension increased the odds of ICAS [smoking, odds ratio (OR): 1.83, p = 0.026; hypertension, OR: 1.84, p = 0.01], whereas hyperlipidemia increased the odds of ECAS (OR: 1.87, p = 0.034).

Conclusion

The distributions of the major risk factors for ischemic stroke were different between smokers and nonsmokers. Cigarette smoking may be more associated with ICAS than with ECAS after adjusting for potential risk factors.  相似文献   

9.

Background

Recent reports have suggested a pathophysiological role of brain-derived neurotrophic factor (BDNF) in attention deficit-hyperactivity disorder (ADHD). We evaluated the plasma levels of BDNF in patients with ADHD.

Methods

Plasma BDNF levels were measured in 41 drug naive ADHD patients and 107 normal controls. The severity of ADHD symptoms was determined by patient scores on the ADHD rating scale (ARS) and the computerized ADHD diagnostic system (ADS).

Results

ANCOVA with age and gender as covariates showed that the mean plasma BDNF levels were significantly higher in ADHD patients than in normal controls (F = 16.968, p < 0.001). There were also significant differences in plasma BDNF levels of ADHD patients and those of normal controls for males and females (Mann–Whitney U-test, p = 0.001 and 0.041, respectively). We also found a significant correlation between plasma BDNF levels and omission errors in ADS outcome-variable T-scores (p < 0.001).

Conclusions

Our study suggests that there is an increase of plasma BDNF levels in untreated ADHD patients, and that plasma BDNF levels had a significant positive correlation with the severity of inattention symptoms. Further studies are required to elucidate the source and role of circulating BDNF in ADHD.  相似文献   

10.

Introduction

Thrombolytic therapy improves clinical outcome in patients with acute ischemic stroke but is compromised by symptomatic intracranial hemorrhage and an unpredictable therapeutic response. In vitro and in vivo data suggest that activation of procarboxypeptidase U (proCPU) inhibits fibrinolysis.

Aims

To investigate whether the extent of proCPU activation is related to efficacy and safety of thrombolytic therapy in ischemic stroke patients.

Methods

In twelve patients with ischemic stroke who were treated with intravenous (n = 7) or intra-arterial (n = 5) thrombolysis, venous blood samples were taken at different time points before, during and after thrombolytic therapy. ProCPU and carboxypeptidase U (CPU, TAFIa) plasma concentrations were determined by HPLC. The maximal CPU activity (CPUmax) and the percentage of proCPU consumption during thrombolytic therapy were calculated. The efficacy and safety of the thrombolytic therapy were assessed by evolution of the clinical deficit, recanalisation, final infarct volume, thrombolysis-induced intracranial hemorrhage and mortality.

Results

No correlations between CPUmax or proCPU consumption and patient or stroke characteristics were found. However, CPUmax is associated with evolution of the clinical deficit and achieved recanalisation. ProCPU consumption is related to the risk of intracranial hemorrhage, mortality and final infarct volume.

Conclusions

Irrespective of patient and stroke characteristics, CPUmax and proCPU consumption during thrombolytic treatment for ischemic stroke are parameters for therapeutic efficacy and safety. Further evaluation of the clinical applicability of these parameters and further investigation of the potential role for CPU inhibitors as adjunctive therapeutics during thrombolytic treatment may be of value.  相似文献   

11.

Objectives

To elucidate the relationship between MetS and ischemic stroke, we evaluated the association of MetS and individual components with frequency of ischemic stroke lesions and investigated the independent associations between them in acute ischemic stroke patients.

Patients and methods

We evaluated 370 acute ischemic stroke patients who underwent brain magnetic resonance (MR) imaging and MR angiography. The stroke subgroups were categorized as intracranial large artery atherosclerosis (IC-LAA, n = 151), extracranial large artery atherosclerosis (EC-LAA, n = 35), and nonatherosclerosis (NA, n = 184). MetS was defined using the criteria of the International Diabetes Federation.

Results

Patients with IC-LAA group showed a higher rate of MetS and previous ischemic lesions (predominantly deep gray/white matter) than those with EC-LAA and NA (all P < 0.001). The number of previous ischemic lesions showed a tendency to increase as the number of MetS components increased in the IC-LAA group (P = 0.004). In the IC-LAA group, age (OR, 1.04) and MetS (OR, 3.28) were independently associated with previous ischemic lesions (all P < 0.001), which was prominent with more severe MetS components after adjustment for risk factors (P < 0.001). Among the component conditions, high blood pressure, impaired fasting glucose, and abdominal obesity were more associated with previous ischemic lesions (all P < 0.001) than low high-density lipoprotein and high triglyceride levels (P = 0.010 and 0.028, respectively).

Conclusion

Our study showed a strong association between MetS and previous ischemic lesions, more in patients with IC-LAA.  相似文献   

12.

Objective

To compare systemic arterial inflammation in subjects with recent ischaemic stroke or TIA and controls with prior cerebrovascular disease.

Methods

Systemic arterial inflammation was prospectively measured by 18F-fluorodeoxygluose positron emission tomography in 11 cases with recent ischaemic stroke or TIA, and 11 sex matched controls with prior cerebrovascular disease.

Results

Hot spots (both carotid and non-carotid) of localised 18FDG uptake were found in more than half of all patients with either recent (n = 6) or prior (n = 8) cerebrovascular disease. There was no significant difference in the total number of hotspots, or hotspots at specific sites, in cases compared with controls. Mean standard uptake values (SUV) were similar in the carotid arteries and aorta of cases and controls, and showed a trend toward higher values in the femoral arteries of the controls (median 1.8; IQR 1.6–2.2) compared to cases (median 1.5; IQR 1.4–1.7).

Conclusion

Arterial inflammation was common, and appeared similar, in patients with recent stroke/TIA, and controls with stroke/TIA more than two years previously.  相似文献   

13.

Objectives

Surveys on stroke prevalence may provide valuable information for planning of healthcare services. Few such studies have been conducted in Latinos and none have been performed in Los Angeles, a County that contains the largest population of Latinos in the United States. We sought to assess the prevalence of self-reported stroke in a population-based sample of community-dwelling Latinos in Los Angeles.

Patients and methods

The group comprised of self-identified Latinos aged 40 years and older from six census tracts in Los Angeles participating in a population-based cross-sectional study of ocular disease in Latinos, The Los Angeles Latino Eye Study (LALES). The prevalence of stroke and its association with demographic, biological and behavioral risk factors was determined. Univariate and multiple stepwise logistic regression models were used to calculate odds ratios (ORs).

Results

The prevalence of self-reported stroke in 6954 community-dwelling Latinos in Los Angeles was 3.3%. Stroke prevalence increased with age (1.4% age 40–50, 3.3% age 50–65, 7.1% age >65), history of hypertension (OR 2.6, p < 0.001), heart disease (OR 4.8, p < 0.001) and diabetic retinopathy (OR 2.1, p = 0.01).

Conclusions

Renewed efforts directed at early identification and treatment of hypertension and heart disease within the Latino community will mitigate the burden of stroke.  相似文献   

14.

Aims and background

The aim of this study is to determine prognostic factors that influence further outcome in patients with glioma.

Methods

Between 01/2002 and 08/2008, 153 patients with malignant gliomas of WHO-grade 3 or 4 who were treated with external beam radiotherapy with or without chemotherapy.

Results

In univariate analysis, following factors were ascertained as statistically significant prognostic parameters: grade (p = 0.000), time between operation and radiotherapy >24 days (p = 0.044) for progression-free survival; grade (p = 0.000), age < 58 years (p = 0.001), extent of surgery (p = 0.011), time between operation and radiotherapy >24 days (p = 0.009), overall treatment time >68 days (p = 0.003), use of chemotherapy (p = 0.015) for overall survival. A longer time period between resection and start of radiotherapy showed to be associated with improved outcome. After multivariate analysis, only grade (p = 0.000) remained a statistically significant factor for progression-free and grade (p = 0.000) and use of chemotherapy (p = 0.031) for overall survival.

Conclusions

We were able to recognize grade and use of chemotherapy as statistically significant prognostic determinants, but not time intervals or overall treatment time.  相似文献   

15.

Objective

Stroke patients with aphasia have a high long-term morbidity. Intravenous rt-PA (iv) thrombolysis is given more deliberately to these patients. Early outcome data is lacking. Aim of this study was to determine early benefit from rt-PA in patients with aphasia.

Methods

Data of stroke patients treated by iv thrombolysis was scrutinized for the presence of aphasia defined as ≥1 point for aphasia on the National Institute of Health Stroke Scale (NIHSS). Improvement was defined as a gain of ≥1 point within 24 h. Cranial computed tomography (CT) scans were evaluated regarding early ischemic changes (EICs), infarct volume and localization.

Results

Fifty patients with aphasia were included. 16 (32%) of patients improved (4 (36%) minor, 7 (41%) moderate, 5 (23%) major stroke patients), while 44 (62%) remained unchanged. Of 28 patients with EICs, 10 (36%) improved compared to 7 out of 22 (32%) patients without (p = 0.773). Aphasia outcome was significantly associated with infarct volume at admission and at 24 h (Kruskal–Wallis, p = 0.033, p ≤ 0.001, respectively).

Conclusion

EICs are not predictive of aphasia outcome and patients with improvement showed smaller infarct volumes. One third improved within 24 h, while two thirds remained unchanged. This might justify a closer follow-up of aphasia in stroke patients at the acute stage.  相似文献   

16.

Background

Chronic dizziness is frequently reported by patients in the chronic stage after ischemic stroke. The aim of this study was to determine the efficacy of cilostazol versus that of aspirin for the chronic dizziness that follows ischemic stroke.

Methods

We performed a prospective, randomized, open-label, blinded endpoint trial. One hundred six patients who suffered supratentorial ischemic stroke within the previous 1–6 months and subsequently complained of persistent dizziness without other obvious sequelae were enrolled. Patients were randomly given cilostazol (200 mg/day) or aspirin (100 mg/day) for 6 months. Rates of improvement in the dizziness were then evaluated. Changes in fixation suppression of the vestibulo-ocular reflex (an indicator of cerebral control over the brainstem reflex related to balance), regional cerebral blood flow (CBF) in the cerebrum, cerebellum, and brainstem; and the Zung Self-Rating Depression Scale (SDS) were also evaluated.

Results

Dizziness was significantly improved in the cilostazol group versus the aspirin group (P < 0.0001) after the 6-month therapy. The capacity for fixation suppression of the vestibulo-ocular reflex was improved (P < 0.0001), and regional CBF in the cerebrum (relative to that in the brainstem [P = 0.003] and to that in the cerebello-brainstem [P = 0.012]) was increased only in the cilostazol group. There was no statistical difference in the change in SDS scores between the two groups.

Conclusion

Cilostazol improves the chronic dizziness that follows ischemic stroke and increases supratentorial CBF and cerebral function for adaptation of the brainstem reflex related to the sense of balance.  相似文献   

17.

Objectives

The effect of family history of hypertension (FHxHT), as a genetic factor predisposing to some ischemic stroke subtypes and independently of hypertension as risk factor, has never been studied.

Methods

A positive FHxHT was searched in 472 patients (312 men, 160 women; mean [S.D.] age, 67.9 [11.4] years) consecutively admitted for a first-ever ischemic stroke (348) or transient ischemic attack (TIA) (124) due to small vessel disease (SVD, 180), large vessel disease (156), or cardioembolism (136). In this population and in three age bands, the genetically transmitted vascular risk factors, age, gender and the ischemic stroke subtypes were compared between those with and without a positive FHxHT.

Results

None of the risk factors was associated with a positive FHxHT, except for hypertension in the whole population (68.9% vs. 48.7%; p = 0.001) and in the <65 year-old patients (72.5% vs. 39.5%; p < 0.001). Regarding the stroke subtypes, a positive FHxHT was only associated with SVD in the subgroup of <65 year-old patients (odd ratios (OR), 2.07; 95% confidence interval (CI), 1.01 to 4.25; p = 0.045). However, this finding disappeared in a logistic regression analysis, which only retained hypertension as independently associated with SVD.

Conclusions

FHxHT is not an independent genetic factor predisposing to some aetiological stroke subtypes.  相似文献   

18.

Objectives

We aimed to investigate the effect of hypercholesterolemia on recovery after acute ischemic stroke.

Methods

Data of 3048 patients admitted for acute ischemic stroke from January to December 2009 were collected from the Stroke Registry in the Chang Gung Healthcare System. Baseline characteristics of patients with and without hypercholesterolemia were compared. The association of hypercholesterolemia with neurological severity and recovery was analyzed using multivariate logistic regression. The patients were then divided on the basis of age for subgroup analysis.

Results

The number of patients with and without a history of hypercholesterolemia was 474 (15.6%) and 2574 (84.4%), respectively. Univariate analysis showed that patients with hypercholesterolemia had a lower National Institutes of Health Stroke Scale (NIHSS) score on admission (p = 0.004). However, during hospitalization, these patients displayed less improvement in their NIHSS score (p = 0.002). These results remained significant in multivariate logistic regression analysis (p < 0.001 and p = 0.002, respectively). Subgroup analysis showed a similar association for hypercholesterolemia in both younger (age < 70) and older (age ≥ 70) age groups.

Conclusions

Acute ischemic stroke in patients with hypercholesterolemia was correlated with reduced severity on admission and less favorable recovery during hospitalization, regardless of age.  相似文献   

19.

Objectives

To prospectively study the efficacy and safety of intraparotid gland injection of Botulinum neurotoxin serotype A (Dysport®) for the treatment of sialorrhea (drooling) in children with cerebral palsy (CP).

Patients and methods

Twenty-four children, ages 21 months to 7 years, were recruited and randomized to receive either treatment with 100 U Botulinum toxin or placebo. Rating scales for the frequency and severity of drooling were performed at the time of injection, at 1 month, and at baseline prior to the second injection. A second set of injections of either 140 U of drug or placebo was given 4 months later, and the same rating scales were used. Eight patients declined the second injection. Due to high dropouts in the placebo group in second set of injections, statistical analysis was performed for the results of the initial injection only.

Results

Scores of the median frequency (p = 0.034) and severity (p = 0.026) of drooling were reduced in the treatment group. Median total score also declined in the treatment group (p = 0.027). After the second injection, five out of nine patients injected with the drug showed a decline in the total score; including three patients who did not respond to the first injection. Only two patients experienced transient increase in drooling after the treatment with the drug.

Conclusion

Botulinum toxin is an effective and safe treatment option for drooling in children with CP.  相似文献   

20.

Objective

Neuromuscular electrical stimulation that incorporates wide pulse widths (1 ms) and high frequencies (100 Hz; wide pulse-NMES (WP-NMES)) augments contractions through an increased reflexive recruitment of motoneurons in individuals without neurological impairments and those with spinal cord injury. The current study was designed to investigate whether WP-NMES also augments contractions after stroke. We hypothesized that WP-NMES would generate larger contractions in the paretic arm compared to the non-paretic arm due to increased reflex excitability for paretic muscles after stroke.

Methods

The biceps brachii muscles were stimulated bilaterally in 10 individuals with chronic hemiparetic stroke. Four stimulation patterns were delivered to explore the effects of pulse width and frequency on contraction amplitude: 20–100–20 Hz (4 s each phase, 1 ms pulse width); 20–100–20 Hz (4 s each phase, 0.1 ms); 20 Hz for 12 s (1 ms); and 100 Hz for 12 s (1 ms). Elbow flexion torque and electromyography were recorded.

Results

Stimulation that incorporated 1 ms pulses evoked more torque in the paretic arm than the non-paretic arm. When 0.1 ms pulses were used there was no difference in torque between arms. For both arms, torque declined significantly during the constant frequency 100 Hz stimulation and did not change during the constant frequency 20 Hz stimulation.

Conclusions

The larger contractions generated by WP-NMES are likely due to increased reflexive recruitment of motoneurons, resulting from increased reflex excitability on the paretic side.

Significance

NMES that elicits larger contractions may allow for development of more effective stroke rehabilitation paradigms and functional neural prostheses.  相似文献   

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