Continuous assessment of electrical epileptic activity in acute stroke.

OBJECTIVE: To determine the incidence and risk factors of electrical seizures and other electrical epileptic activity using continuous EEG (cEEG) in patients with acute stroke. METHODS: One hundred consecutive patients with acute stroke admitted to our stroke unit underwent cEEG using 10 electrodes. In addition to electrical seizures, repetitive focal sharp waves (RSHWs), repetitive focal spikes (RSPs), and periodic lateralized epileptic discharges (PLEDs) were recorded. RESULTS: In the 100 patients, cEEG was recorded for a mean duration of 17 hours 34 minutes (range 1 hour 12 minutes to 37 hours 10 minutes). Epileptic activity occurred in 17 patients and consisted of RSHWs in seven, RSPs in seven, and PLEDs in three. Electrical seizures occurred in two patients. On univariate Cox regression analysis, predictors for electrical epileptic activity were stroke severity (high score on the National Institutes of Health Stroke Scale) (hazard ratio [HR] 1.12; p = 0.002), cortical involvement (HR 5.71; p = 0.021), and thrombolysis (HR 3.27; p = 0.040). Age, sex, stroke type, use of EEG-modifying medication, and cardiovascular risk factors were not predictors of electrical epileptic activity. On multivariate analysis, stroke severity was the only independent predictor (HR 1.09; p = 0.016). CONCLUSION: In patients with acute stroke, electrical epileptic activity occurs more frequently than previously suspected.

Migraine and patent foramen ovale: A residual coincidence or a pathophysiological intrigue?

Migraine is one of the most common neurological disorders and one of the most frequent primary headaches. It imposes a significant burden on the affected individuals, society and health care system. As the etiology and pathophysiology of migraine are not well understood, treatment is largely symptomatic. Patent foramen ovale is a remnant of a fetal circulation and is highly prevalent in the general population. Its presence was linked to several disorders including migraine. The aim of this review was to search in the available data the answer to the question whether the link between migraine and patent foramen ovale is coincidental or whether they represent a pathophysiological entity.

Changes in artistic style after minor posterior stroke.

BACKGROUND: Two professional painters experienced significant changes in their art as the main consequence of minor stroke located in the left occipital lobe or thalamus. METHODS: The features of this artistic conversion were analysed on the basis of extensive neurological, neuropsychological, and psychiatric evaluations. RESULTS: Both painters, initially unaware of the artistic changes, exhibited mild signs of executive dysfunction, but no general cognitive decline. The first painter, who showed mild visual-perceptive difficulties (dyschromatopsia and scotoma in his right upper visual field after left occipital stroke), together with increased anxiety and difficulty in emotional control, switched to a more stylised and symbolic art. The second painter, who also presented features of emotionalism related to his left latero-thalamic stroke, switched from an impressionist style to a more joyous and geometric, but more simplistic, abstract art. CONCLUSIONS: These findings show that mild cognitive and affective modifications due to focal posterior brain lesions can have significant repercussions on artistic expression.

Stroke patterns, etiology, and prognosis in patients with diabetes mellitus.

BACKGROUND: Although diabetes mellitus (DM) is a risk factor for stroke, it is unclear whether stroke features are different in diabetic vs nondiabetic individuals. OBJECTIVE: To assess the role of DM in stroke patients. METHODS: Risk factors, etiology, lesion topography, clinical features, and outcome were assessed in 611 diabetic individuals (history of DM or fasting plasma glucose level of > or =7.0 mmol/L) among 4,064 consecutive patients of the Lausanne Stroke Registry. RESULTS: Patients with DM were 5.3 years older than non-DM patients. After multivariate analysis, DM was associated with lower relative prevalence of intracerebral hemorrhage (ICH; odds ratio [95% CI]: 0.63 (0.45 to 0.9); p = 0.022), higher relative prevalence of subcortical infarction (SCI; 1.34 [1.11 to 1.62]; p = 0.009), and higher relative frequency of small-vessel (SVD; 1.78 [1.31 to 3.82]; p = 0.012) and large-artery (LAD; 2.02 [1.31 to 2.02]; p = 0.002) disease. In the cohort of diabetic stroke patients, there was no interaction of DM with either hypertension or age for the outcomes of ICH, SCI, SVD, and LAD. Moderate to severe deficit on admission (31.1 vs 31.6%; p = 0.4) and poor functional outcome at 1 month (14.1 vs 15.3%; p = 0.24) did not differ in patients with DM compared with non-DM patients. In multivariate analysis, neither DM (0.86 [0.63 to 1.11]; p = 0.15) nor hypertension (1.09 [0.91 to 1.39]; p = 0.32) was associated with poor functional outcome. CONCLUSIONS: Diabetic stroke patients are associated with specific patterns of stroke type, etiology, and topography but not with poor functional outcome. There was no interaction between DM and hypertension or age.

Prodromal and early epileptic seizures in acute stroke: does higher serum cholesterol protect?

In a case-control study, patients (n = 43/3,628) presenting seizures <1 week before (n = 6), < or =3 hours after (n = 26), and 3 to 24 hours after (n = 11) a first-ever stroke were studied. On multivariate analysis, they were characterized by lower levels of serum cholesterol (5.86 +/- 0.51 vs 6.34 +/- 0.58; p < 0.0001). Mortality and functional outcome at discharge were not influenced. Early poststroke seizures occur mainly during the critical 3-hour window for thrombolysis. Hypercholesterolemia appears to protect against seizures and cerebral ischemia.

Stroke or transient ischemic attacks with basilar artery stenosis or occlusion: clinical patterns and outcome.

BACKGROUND: Basilar artery occlusion (BAO) is associated with a high mortality rate, although cases with spontaneous favorable outcomes have recently been reported, and basilar artery stenosis (BAS) has received little consideration until now. OBJECTIVE: To study the prognostic clinical factors by testing numerous combinations of admission status characteristics of patients with brain ischemia caused by BAO or BAS. METHODS: We conducted a retrospective review from the Lausanne Stroke Registry (group 1) of patients with stroke or transient ischemic attack caused by BAS less than 50% or BAO as diagnosed by magnetic resonance angiography who were not treated by thrombolysis. Neurologic findings on admission were correlated with outcomes. We compared clinical patterns associated with poor outcomes in group 1 with those in patients with stroke who died from BAO or BAS (confirmed at autopsy) (group 2). RESULTS: Eighty-eight patients were studied. The outcomes of patients with stroke in group 1 (35/43) was poor (severe disability or death) in 54% of cases. A statistical analysis revealed that 4 factors-dysarthria, pupillary disorders, lower cranial nerve involvement, and consciousness disorders on admission-were strongly (P<.001) associated with poor outcomes. The multivariate analysis showed that the outcome was poor in 100% of cases in which consciousness disorders or the combination of the remaining 3 factors were present, whereas in the absence of these factors, a poor outcome was reported in only 11%. In 87% of the 45 patients with stroke in group 2, the same clinical patterns were present on admission. CONCLUSIONS: The prognosis of BAS greater than 50% or BAO is diverse and certain clinical characteristics seem to predict a lower risk of poor outcome. Their presence may help to decide the most suitable therapy.

Automatic classification of HITS into artifacts or solid or gaseous emboli by a wavelet representation combined with dual-gate TCD.

BACKGROUND AND PURPOSE: Transcranial Doppler (TCD) can detect high-intensity transient signals (HITS) in the cerebral circulation. HITS may correspond to artifacts or solid or gaseous emboli. The aim of this study was to develop an offline automated Doppler system allowing the classification of HITS. METHODS: We studied 600 HITS in vivo, including 200 artifacts from normal subjects, 200 solid emboli from patients with symptomatic internal carotid artery stenosis, and 200 gaseous emboli in stroke patients with patent foramen ovale. The study was 2-fold, each part involving 300 HITS (100 of each type). The first 300 HITS (learning set) were used to construct an automated classification algorithm. The remaining 300 HITS (validation set) were used to check the validity of this algorithm. To classify HITS, we combined dual-gate TCD with a wavelet representation and compared it with the current "gold standard," the human experts. RESULTS: A combination of the peak frequency of HITS and the time delay makes it possible to separate artifacts from emboli. On the validation set, we achieved a sensitivity of 97%, a specificity of 98%, a positive predictive value (PPV) of 99%, and a negative predictive value (NPV) of 94%. To distinguish between solid and gaseous emboli, where positive refers now to the solid emboli, we used the peak frequency, the relative power, and the envelope symmetry of HITS. On the validation set, we achieved a sensitivity of 89%, a specificity of 86%, a conditional PPV of 89%, and a conditional NPV of 89%. CONCLUSIONS: An automated wavelet representation combined with dual-gate TCD can reliably reject artifacts from emboli. From a clinical standpoint, however, this approach has only a fair accuracy in differentiating between solid and gaseous emboli.

Three-dimensional computed tomography angiography and magnetic resonance angiography of carotid bifurcation stenosis.

PURPOSE: To evaluate the role of computed tomography angiography (CTA) and magnetic resonance angiography (MRA) in the quantification of atherosclerotic stenosis of carotid artery bifurcation in comparison with digital substraction angiography (DSA) and Doppler sonography (DS). MATERIALS AND METHODS: Twenty-five patients with atherosclerotic disease of the carotid arteries with proven stenosis by DSA, had spiral CTA, MRA using two- and three-dimensional time-of-flight gradient echo techniques, and DS using Doppler flow signal recording (total 47 carotid artery bifurcations). The degree of stenosis was measured according to the North American Symptomatic Carotid Endarterectomy Trial criteria: total occlusion (100%), severe (70-99%), moderate (30-69%) and mild (0-29%). The degree of stenosis measured by CTA, MRA and DS was compared to DSA, used as the gold standard. RESULTS: Ninety-seven percent of MRA measures were equivalent to DSA, and 3% were underestimated; 96% of CTA measures were equivalent to DSA, and 4% were underestimated; 77% of DS measures were equivalent to DSA, 21% were overestimated and 2% were underestimated. CONCLUSIONS: CTA and MRA are equally accurate methods in quantifying the degree of carotid bifurcation stenosis.

Uncommon ultrasound findings in traumatic extracranial vertebral artery dissection.

We report a case of internal carotid artery dissection (ICAD) associated with contralateral vertebral artery dissection (VAD). The interest of this case is to discuss an unusual Doppler pattern manifesting by a spectrum of an alternating vertebral artery flow suggesting a hemodynamic contribution from the contralateral vertebral artery (VA) and a clear depiction of both antegrade (red) and retrograde (blue) flow within the false and true lumen of the VAD by color Duplex flow imaging.

Stroke with internal carotid artery stenosis.

BACKGROUND: Stroke patterns in patients with different degrees of carotid stenosis have not been systematically studied. OBJECTIVE: To determine first-ever stroke subtypes in nonselected patients with extracranial internal carotid artery (ICA) stenosis, based on a primary care hospital stroke registry. METHODS: One hundred seventy-three patients who experienced their first-ever stroke and who had 50% or greater (North American Symptomatic Carotid Endarterectomy Trial method) ipsilateral extracranial ICA stenosis, corresponding to 6.5% of 2649 patients with anterior circulation stroke included in the Lausanne Stroke Registry, were studied. All these patients underwent Doppler ultrasonography, carotid angiography (conventional or magnetic resonance angiography), neuroimaging (computed tomography or magnetic resonance imaging), and other investigations from the standard protocol of the Lausanne Stroke Registry. RESULTS: We found the following types of infarct in the middle cerebral artery territory: anterior pial in 54 (31%) of the patients; subcortical, 34 (20%); posterior pial, 32 (19%); large hemispheral, 20 (12%); and border zone, 17 (10%). There were multiple pial in 14 (8%) and multiple deep infarcts in 2 (1%) of the patients. Moderate (50%-69%) ICA stenosis was significantly associated with large hemispheral infarcts and a normal contralateral ICA (P =.04 and P =.02, respectively). Seventy percent to 89% of ICA stenosis was associated with prior transient ischemic attacks (P =.02). After adjusting for cardioembolism, border zone infarcts showed a strong trend to appear mostly in patients with 90% to 99% ICA stenosis (P =.06). CONCLUSIONS: The association of a large hemispheral infarct with moderate ICA stenosis suggests a large embolism and/or an inadequate collateral supply. While an embolism may also contribute, the association of border zone infarcts with 90% to 99% ICA stenosis emphasizes the significance of hemodynamic disturbance in the pathogenesis of these types of infarct.

Recent progress in drug treatment for acute ischemic stroke.

The publication of the positive results of the National Institute of Neurological Disorders and Stroke (NINDS) trial of alteplase (a recombinant tissue plasminogen activator; rt-PA) for acute stroke patients in 1995 and its approval by the US Food and Drug Administration as well as the American Academy of Neurology and American Heart Association increased the interest and attention of the medical community in acute stroke treatment. However, the implication of this NINDS Stroke Study and other thrombolytic trials in clinical practice remains controversial and debated. Furthermore, the recent publication of the results from the European Cooperative Acute Stroke Study II (ECASS II) and Alteplase Thrombolysis of Acute Noninterventional Therapy in Ischemic Stroke (ATLANTIS) studies will feed the controversy, since the results of these two studies are disappointing and do not confirm the positive results of the NINDS Stroke Study as expected by clinicians managing patients with acute stroke. The Standard Treatment with Alteplase to Reverse Stroke (STARS) and Cleveland studies, which involved a large number of community hospitals to assess the safety profile and the benefit of rt-PA thrombolysis for acute stroke patients in clinical practice, have shown controversial results. Consequently, the issue arises of which is the more reasonable position concerning thrombolysis by alteplase, which seems to work but has not been proven yet beyond reasonable doubt? The recent publication of the results from the Prolyse in Acute Cerebral Thromboembolism (PROACT II) study has shown that intra-arterial thrombolysis with prourokinase is a benefit treatment in stroke patients with a proven middle cerebral artery occlusion within 6 h of stroke onset. Numerous trials devoted to neuroprotection against acute ischemic stroke have been prematurely stopped because of safety concerns or poor risk-benefit ratios, but some new neuroprotective drugs seem promising and are being tested in ongoing studies. The third issue under study concerns the use of antithrombotic drugs in the acute phase of stroke, particularly the new potent platelet glycoprotein IIb/IIIa antagonists such as abciximab. In this paper, we have reviewed selected recent clinical trials focusing on recent advances in acute stroke therapy.

Atrial fibrillation with small subcortical infarcts.

OBJECTIVES: To evaluate the characteristics of cardioembolic small (maximum lesion diameter<1.5 cm) subcortical infarcts (SSI) in patients with atrial fibrillation (AF). METHODS: Twenty seven patients with chronic AF and an isolated SSI established by CT/MRI in the anterior circulation (SSI-AF group) were evaluated and their characteristics compared with those of 45 age matched (+/-1 year) patients with SSI, but no arterial or cardiac embolic source (SSI-control group). Using the criterion of the presence or absence of established risk factors (hypertension or diabetes mellitus) for small artery disease (SAD), the SSI-AF group we also subdivided into two groups, SSI-AF-SAD+ (n=22) and SSI-AF-SAD- (n=5) and their characteristics compared. RESULTS: Although the lack of any significant difference in the distribution of hypertension and diabetes mellitus between the SSI-AF and SSI-control groups emphasises SAD as a common cause of infarct in SSI-AF, the presence of AF-together with the higher frequency of neuropsychological disturbances in the SSI-AF group versus the SSI-control group (15% v 2%; p=0.066)-favours cardioembolism as a potential cause of infarct in several patients. The characteristic factors seen more often in the SSI-AF-SAD- group compared with the SSI-AF-SAD+ group were secondary haemorrhagic transformation, faciobrachial pure motor weakness, subinsular involvement, and better recovery of neurological deficits. CONCLUSIONS: The study suggests that either SAD or cardioembolism can be the cause of SSI in patients with AF. Atrial fibrillation is not always coincidental in patients with SSI and a clinical lacunar stroke. Certain clinical and radiological findings may be useful in differentiating cardioembolism from SAD in patients with SSI.

The matching pursuit: a new method of characterizing microembolic signals?

Detection of clinically silent circulating microemboli within cerebral arteries by transcranial Doppler ultrasound (US) is now being widely investigated in the hope of identifying patients at increased risk for stroke. However, the widespread application of embolus detection is still limited in clinical practice because current transcranial Doppler systems have not the required sensitivity and specificity to analyze microembolic signals, particularly to distinguish between gaseous, or solid brain emboli and artefacts. In this work, we proposed to investigate the potential of a new approach for the analysis of microembolic signals via the so-called matching pursuit, which is closely related to wavelet transform and is not subject to the same limitations as the fast Fourier transform. Our preliminary results clearly indicate that matching pursuit is well suited to this task.

[Cholesterol and stroke risk: a role for statins?]. / Cholestérol et risque d'accident vasculaire cérébral: un rôle pour les statines?

Atherosclerosis is the most common cause of vascular diseases, but the relevance of cholesterol has only been definitely associated with coronary artery disease and peripheral vascular disease. In comparison, the role of cholesterol in stroke is, while a tempting assumption, subject to controversy in the literature. The crucial question--is cholesterol a risk factor for stroke?--remains open. Recent trials with statin drugs, such as 4 S, CARE, LIPID and WOSCOP, have created a new wave of enthusiasm by showing decreased risk of stroke in the statin-treated patients. However, these trials are most often designed for patients with a known history of coronary artery disease. In contrast, studies investigating the impact of statins in the secondary prevention of stroke are still lacking. Moreover, the beneficial effects of statins on clinical events may involve non-cholesterol mechanisms. In regard to stroke prevention, there is no absolute evidence to recommend the use of statin drug therapy.