Wednesday, November 30, 2011

Abnormalities in thalamic neurophysiology in schizophrenia: Could psychosis be a result of potassium

Publication year: 2011
Source: Neuroscience & Biobehavioral Reviews, Available online 28 November 2011
Zoran Vukadinovic, Ivana Rosenzweig
Psychosis in schizophrenia is associated with source-monitoring deficits whereby self-initiated behaviors become attributed to outside sources. One of the proposed functions of the thalamus is to adjust sensory responsiveness in accordance with the behavioral contextual cues. The thalamus is markedly affected in schizophrenia, and thalamic dysfunction may here result in reduced ability to adjust sensory responsiveness to ongoing behavior. One of the ways in which the thalamus accomplishes the adjustment of sensory processing is by a neurophysiological shift to post-inhibitory burst firing mode prior to and during certain exploratory actions. Reduced amount of thalamic burst firing may result from increased neuronal excitability secondary to a reported potassium channel dysfunction in schizophrenia. Pharmacological agents that reduce the excitability of thalamic cells and thereby promote burst firing by and large tend to have antipsychotic effects

Highlights

► Schizophrenia may involve failure in internal monitoring of self-initiated motor outputs. The thalamus may be involved in monitoring of efferent cortical motor outputs. The thalamus has been found to be markedly affected in schizophrenia. The thalamus displays burst firing mode prior to exploratory behaviors. Pharmacological agents that promote burst firing in the thalamus may have antipsychotic effects





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Tuesday, November 29, 2011

Soccer Headers Can Cause Brain Injury

Researchers at Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center, the University Hospital and academic medical center for Einstein, used diffusion tensor imaging, an advanced type of MRI-based imaging technique, as well as cognitive tests, to assess brain function in amateur football players...





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Scan't Evidence: Do MRIs Relieve Symptoms of Depression?

When a researcher asks a volunteer to slide head-first into the open eye of a magnetic resonance imaging (MRI) machine, the expectation is that the device's magnetic field will penetrate the skull to produce a faithful picture of the brain without changing its behavior. A new study suggests, however, that MRI machines do, in fact, manipulate brain activity--and they change the brain in a way that helps treat depression. In other words, MRIs may be unintentional antidepressants . [More]

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A Comparison of Acute Hemorrhagic Stroke Outcomes in 2 Populations: The Crete-Boston Study [Original

Background and Purpose—

Although corticosteroid use in acute hemorrhagic stroke is not widely adopted, management with intravenous dexamethasone has been standard of care at the University Hospital of Heraklion, Crete with observed outcomes superior to those reported in the literature. To explore this further, we conducted a retrospective, multivariable-adjusted 2-center study.

Methods—

We studied 391 acute hemorrhagic stroke cases admitted to the University Hospital of Heraklion, Crete between January 1997 and July 2010 and compared them with 510 acute hemorrhagic stroke cases admitted to Massachusetts General Hospital, Boston, from January 2003 to September 2009. Of the Cretan cases, 340 received a tapering scheme of intravenous dexamethasone, starting with 16 to 32 mg/day, whereas the Boston patients were managed without steroids.

Results—

The 2 cohorts had comparable demographics and stroke severity on admission, although anticoagulation was more frequent in Boston. The in-hospital mortality was significantly lower on Crete (23.8%, n=340) than in Boston (38.0%, n=510; P<0.001) as was the 30-day mortality (Crete: 25.4%, n=307; Boston: 39.4%, n=510; P<0.001). Exclusion of patients on anticoagulants showed even greater differences (30-day mortality: Crete 20.8%; n=259; Boston 37.0%; n=359; P<0.001). The improved survival on Crete was observed 3 days after initiation of intravenous dexamethasone and was pronounced for deep-seated hemorrhages. After adjusting for acute hemorrhagic stroke volume/location, Glasgow Coma Scale, hypertension, diabetes mellitus, smoking, coronary artery disease and statin, antiplatelet, and anticoagulant use, intravenous dexamethasone treatment was associated with better functional outcomes and significantly lower risk of death at 30 days (OR, 0.357; 95% CI, 0.174–0.732).

Conclusions—

This study suggests that intravenous dexamethasone improves outcome in acute hemorrhagic stroke and supports a randomized clinical trial using this approach.






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Contrast Extravasation on Computed Tomography Angiography Predicts Clinical Outcome in Primary Intra

Background and Purpose—

Several retrospective studies suggested that contrast extravasation on CT angiography predicts hematoma expansion, poor outcome, and mortality in primary intracerebral hemorrhage. We aimed to determine the predictive value of contrast extravasation on multidetector CT angiography for clinical outcome in a prospective study.

Methods—

In 160 consecutive patients with spontaneous intracerebral hemorrhage admitted within 6 hours of symptom onset, noncontrast CT and multidetector CT angiography were performed on admission. A follow-up noncontrast CT was done at 24 hours. Multidetector CT angiography images were analyzed to identify the presence of contrast extravasation. Clinical outcome was assessed by modified Rankin Scale on discharge and at 90 days.

Results—

A total of 139 patients with primary intracerebral hemorrhage were included in the final analysis. Contrast extravasation occurred in 30 (21.6%) patients. The presence of contrast extravasation was associated with increased hematoma expansion (P<0.0001), in-hospital mortality (P=0.008), prolonged hospital stay (P=0.006), poor outcome on discharge (P=0.025), increased 3-month mortality (P=0.009), and poor clinical outcome (P<0.0001). In multivariate analysis, contrast extravasation was a promising independent predictor (OR, 10.5; 95% CI, 3.2–34.7; P<0.0001) for 90-day poor clinical outcome followed by the presence of intraventricular hemorrhage (OR, 3.4; 95% CI, 1.5–7.7; P=0.003) and initial hematoma volume (OR, 1.0; 95% CI, 1.0–1.1; P=0.013).

Conclusions—

The presence of contrast extravasation on multidetector CT angiography in patients with hyperacute-stage intracerebral hemorrhage is an independent and strong factor associated with poor outcome. Any patient with intracerebral hemorrhage with such sign on multidetector CT angiography should be monitored intensely and treated accordingly.






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Presence of Intracranial Artery Calcification Is Associated With Mortality and Vascular Events in Pa

Background and Purpose—

Although intracranial artery calcification (IAC) has been reported to be a risk factor for ischemic stroke, the prognostic implications of IAC in stroke outcome are unknown. The purpose of this study was to determine the association between IAC and risk of vascular events and death in patients with stroke after hospital discharge.

Methods—

All patients with ischemic stroke over a 1-year period were included (n=302). IAC, assessed by multidetector CT, was defined as hyperdense foci (peak density >130 Hounsfield units) and assessed in the 7 major cerebral arteries. The IAC scores ranged from 0 (no calcification) to 7. Follow-up information on major clinical events (including fatal or nonfatal ischemic stroke, cardiac and peripheral artery events, and all-cause death) was obtained by means of a structured phone interview.

Results—

IAC was present in 260 patients (83%). With a mean follow-up of 773±223 days, 88 major clinical events occurred in 67 patients (22%): 45 new ischemic vascular events (ischemic stroke: n=22; cardiac event: n=15; peripheral artery event: n=8) and 43 deaths from any cause. Patients with the highest IAC scores had significantly higher rates of death and vascular events than those with the lowest IAC scores (log rank test, P=0.029). In the Cox proportional hazards regression model, the IAC score was significantly associated with major clinical events (hazard ratio, 1.34; 95% CI, 1.11–1.61; P=0.002).

Conclusions—

In patients with ischemic stroke, IAC detection may constitute a simple marker of a high risk of future major clinical events.






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Velocity Criteria for Intracranial Stenosis Revisited: An International Multicenter Study of Transcr

Background and Purpose—

Intracranial atherosclerotic disease is associated with a high risk of stroke recurrence. We aimed to determine accuracy of transcranial Doppler screening at laboratories that share the same standardized scanning protocol.

Methods—

Patients with symptoms of cerebral ischemia were prospectively studied. Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) criteria were used for identification of ≥50% stenosis. We determined velocity cutoffs for ≥70% stenosis on digital subtraction angiography by Warfarin–Aspirin Symptomatic Intracranial Disease criteria and evaluated novel stenotic/prestenotic ratio and low-velocity criteria.

Results—

A total of 102 patients with intracranial atherosclerotic disease (age 57±13 years; 72% men; median National Institutes of Health Stroke Scale 3, interquartile range 6) provided 690 transcranial Doppler/digital subtraction angiography vessel pairs. On digital subtraction angiography, ≥50% stenosis was found in 97 and ≥70% stenosis in 62 arteries. Predictive values for transcranial Doppler SONIA criteria were similar (P>0.9) between middle cerebral artery (sensitivity 78%, specificity 93%, positive predictive value 73%, negative predictive value 94%, and overall accuracy 90%) and vertebral artery/basilar artery (69%, 98%, 88%, 93%, and 92%). As a single velocity criterion, most sensitive mean flow velocity thresholds for ≥70% stenosis were: middle cerebral artery >120 cm/s (71%) and vertebral artery/basilar artery >110 cm/s (55%). Optimal combined criteria for ≥70% stenosis were: middle cerebral artery >120 cm/s, or stenotic/prestenotic ratio ≥3, or low velocity (sensitivity 91%, specificity 80%, receiver operating characteristic 0.858), and vertebral artery/basilar artery >110 cm/s or stenotic/prestenotic ratio ≥3 (60%, 95%, 0.769, respectively).

Conclusions—

At laboratories with a standardized scanning protocol, SONIA mean flow velocity criteria remain reliably predictive of ≥50% stenosis. Novel velocity/ratio criteria for ≥70% stenosis increased sensitivity and showed good agreement with invasive angiography.






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Atherosclerosis and Dementia: A Cross-Sectional Study With Pathological Analysis of the Carotid Arte

Background and Purpose—

Previous ultrasound-based studies have shown an association between carotid artery atherosclerosis and dementia. Our aim was to investigate this association using postmortem examination.

Methods—

Postmortem morphometric measurements of carotid stenosis and intima-media thickness were performed in individuals with dementia (n=112) and control subjects (n=577). Multivariate logistic regression models were applied.

Results—

High-grade left internal carotid stenosis (≥70%) was associated with increased odds for dementia (OR, 2.30; 95% CI, 1.14–4.74; P=0.02). Intima-media thickness was not associated with dementia.

Conclusions—

The likelihood of dementia is increased with high-grade left internal carotid artery atherosclerosis after adjusting for demographic and cardiovascular risk factors.






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Hemostatic Therapy in Experimental Intracerebral Hemorrhage Associated With the Direct Thrombin Inhi

Background and Purpose—

Dabigatran-etexilate (DE) recently has been approved for stroke prevention in atrial fibrillation. However, lack of effective antagonists represents a major concern in the event of intracerebral hemorrhage (ICH). The aims of the present study were to establish a murine model of ICH associated with dabigatran, and to test the efficacy of different hemostatic factors in preventing hematoma growth.

Methods—

In C57BL/6 mice receiving DE (4.5 or 9.0 mg/kg), in vivo and in vitro coagulation assays and dabigatran plasma levels were measured repeatedly. Thirty minutes after inducing ICH by striatal collagenase injection, mice received an intravenous injection of saline, prothrombin complex concentrate (PCC; 100 U/kg), murine fresh-frozen plasma (200 μL), or recombinant human factor VIIa (8.0 mg/kg). ICH volume was quantified on brain cryosections 24 hours later.

Results—

DE substantially prolonged tail vein bleeding time and ecarin clotting time for 4 hours corresponding to dabigatran plasma levels. Intracerebral hematoma expansion was observed mainly during the first 3 hours on serial T2* MRI. Anticoagulation with high doses of DE increased the hematoma volume significantly. PCC and, less consistently, fresh-frozen plasma prevented excess hematoma expansion caused by DE, whereas recombinant human factor VIIa was ineffective. Prevention of hematoma growth and reversal of tail vein bleeding time by PCC were dose-dependent.

Conclusions—

The study provides strong evidence that PCC and, less consistently, fresh-frozen plasma prevent excess intracerebral hematoma expansion in a murine ICH model associated with dabigatran. The efficacy and safety of this strategy must be further evaluated in clinical studies.






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Fatalism, Optimism, Spirituality, Depressive Symptoms, and Stroke Outcome: A Population-Based Analys

Background and Purpose—

We sought to describe the association of spirituality, optimism, fatalism, and depressive symptoms with initial stroke severity, stroke recurrence, and poststroke mortality.

Methods—

Stroke cases from June 2004 to December 2008 were ascertained in Nueces County, TX. Patients without aphasia were queried on their recall of depressive symptoms, fatalism, optimism, and nonorganizational spirituality before stroke using validated scales. The association between scales and stroke outcomes was studied using multiple linear regression with log-transformed National Institutes of Health Stroke Scale and Cox proportional hazards regression for recurrence and mortality.

Results—

Six hundred sixty-nine patients participated; 48.7% were women. In fully adjusted models, an increase in fatalism from the first to third quartile was associated with all-cause mortality (hazard ratio, 1.41; 95% CI, 1.06–1.88) and marginally associated with risk of recurrence (hazard ratio, 1.35; 95% CI, 0.97–1.88), but not stroke severity. Similarly, an increase in depressive symptoms was associated with increased mortality (hazard ratio, 1.32; 95% CI, 1.02–1.72), marginally associated with stroke recurrence (HR, 1.22; 95% CI, 0.93–1.62), and with a 9.0% increase in stroke severity (95% CI, 0.01–18.0). Depressive symptoms altered the fatalism–mortality association such that the association of fatalism and mortality was more pronounced for patients reporting no depressive symptoms. Neither spirituality nor optimism conferred a significant effect on stroke severity, recurrence, or mortality.

Conclusions—

Among patients who have already had a stroke, self-described prestroke depressive symptoms and fatalism, but not optimism or spirituality, are associated with increased risk of stroke recurrence and mortality. Unconventional risk factors may explain some of the variability in stroke outcomes observed in populations and may be novel targets for intervention.






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Age and Outcomes After Carotid Stenting and Endarterectomy: The Carotid Revascularization Endarterec

Background and Purpose—

High stroke event rates among carotid artery stenting (CAS)-treated patients in the Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST) lead-in registry generated an a priori hypothesis that age may modify the relative efficacy of CAS versus carotid endarterectomy (CEA). In the primary CREST report, we previously noted significant effect modification by age. Here we extend this investigation by examining the relative efficacy of the components of the primary end point, the treatment-specific impact of age, and contributors to the increasing risk in CAS-treated patients at older ages.

Methods—

Among 2502 CREST patients with high-grade carotid stenosis, proportional hazards models were used to examine the impact of age on the CAS-to-CEA relative efficacy, and the impact of age on risk within CAS-treated and CEA-treated patients.

Results—

Age acted as a treatment effect modifier for the primary end point (P interaction=0.02), with the efficacy of CAS and CEA approximately equal at age 70 years. For CAS, risk for the primary end point increased with age (P<0.0001) by 1.77-times (95% confidence interval, 1.38–2.28) per 10-year increment; however, there was no evidence of increased risk for CEA-treated patients (P=0.27). Stroke events were the primary contributor to the overall effect modification (P interaction=0.033), with equal risk at 64 years. The treatment-by-age interaction for CAS and CEA was not altered by symptomatic status (P=0.96) or by sex (P=0.45).

Conclusions—

Outcomes after CAS versus CEA were related to patient age, attributable to increasing risk for stroke after CAS at older ages. Patient age should be an important consideration when choosing between the 2 procedures for treating carotid stenosis.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00004732.






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Effects of Carotid Endarterectomy or Stenting on Blood Pressure in the International Carotid Stentin

Background and Purpose—

Arterial hypotension is more frequently observed early after carotid artery stenting (CAS) than after carotid endarterectomy (CEA), but their long-term effects on blood pressure (BP) are unclear. We compared the effects of CAS and CEA on BP up to 1 year after treatment in the International Carotid Stenting Study.

Methods—

Patients with symptomatic carotid stenosis were randomly allocated to CAS or CEA. Systolic and diastolic BP were recorded at baseline, at discharge, and at 1, 6, and 12 months. Antihypertensive medication use was recorded. A per-protocol analysis was performed. Patients with missing BP records were excluded. Between-group BP changes were compared and adjusted for baseline covariates with linear regression. Within-group BP changes were compared with the paired t test.

Results—

CAS (N=587) and CEA (N=637) were both associated with a decrease in BP at discharge, which was greater after CAS (mean difference in systolic BP between groups, 10.3 mm Hg; 95% CI, 7.3–13.3; P<0.0001; in diastolic BP, 4.1 mm Hg; 95% CI, 2.4–5.7; P<0.0001). During follow-up, BP changes were not different between groups. Adjustment for differences in baseline characteristics did not change the results. Fewer patients undergoing CAS used antihypertensive medication during follow-up than patients undergoing CEA (relative risk at 12 months, 0.91; 95% CI, 0.85–0.97; P=0.0073).

Conclusions—

CAS leads to a larger early decrease in BP than CEA, but this effect does not persist over time. CAS may lessen the requirement for antihypertensive medication more than CEA.

Clinical Trial Registration—

URL: www.controlled-trials.com. Unique identifier: ISRCTN25337470.






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Intracranial Stenting of Subacute Symptomatic Atherosclerotic Occlusion Versus Stenosis [Original Co

Background and Purpose—

Limited data are available concerning the outcome of angioplasty/stenting for subacute atherosclerotic intracranial artery occlusion, which is often associated with progressive symptom development in the salvageable brain under ischemic threat due to poor collateral blood supply.

Methods—

Among 177 patients who underwent angioplasty and/or stenting for severe symptomatic intracranial steno-occlusion, 26 had subacute atherosclerotic intracranial artery occlusion. Outcome after stenting (N=22) was assessed according to procedural success (return of antegrade flow and residual stenosis <50%), adverse event (any stroke or death) rate, and restenosis (>50%) using weighted Cox proportional hazards regression in the overall cohort and in separate subgroups.

Results—

Successful recanalization was achieved in 95%. Three adverse events (13.6%) occurred among patients undergoing stenting for occlusion, including 2 major strokes and 1 nonprocedure-related death. Good outcome (modified Rankin Scale ≤2) was achieved in 73%. In the overall cohort, no significant difference was observed between the occlusion and stenosis groups in terms of the risk of adverse events (hazard ratio for the occlusion group, 1.055; 95% CI, 0.29–3.90) or the risk of restenosis (hazard ratio for the occlusion group, 1.2; 95% CI, 0.19–7.72). A trend toward a higher rate of adverse events was observed in older age (>65 years), progressive worsening, balloon-expandable stent, and no history of a preprocedural P2Y12 assay.

Conclusions—

In a cohort of patients undergoing angioplasty/stenting for subacute atherosclerotic intracranial artery occlusion, no significant difference in the rates of adverse events was observed. However, several factors, including age, tended to be associated with a higher event rate.






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Prediction of Malignant Middle Cerebral Artery Infarction Using Computed Tomography-Based Intracrani

Background and Purpose—

Early decompressive surgery in patients with malignant middle cerebral artery (MCA) infarction improves outcome. Elevation of intracranial pressure depends on both the space occupying brain edema and the intracranial volume reserve (cerebrospinal fluid [CSF]). However, CSF volume was not investigated as a predictor of malignant infarction so far. We hypothesize that assessment of CSF volume in addition to admission infarct size improves early prediction of malignant MCA infarction.

Methods—

Stroke patients with carotid-T or MCA main stem occlusion and ischemic lesion (reduced cerebral blood volume [CBV]) on perfusion CT were considered for the analysis. The end point malignant MCA infarction was defined by clinical signs of herniation. Volumes of CSF and CBV lesion were determined on admission. Receiver-operator characteristics analysis was used to calculate predictive values for radiological and clinical measurements.

Results—

Of 52 patients included, 26 (50%) developed malignant MCA infarction. Age, a decreased level of consciousness on admission, CBV lesion volume, CSF volume, and the ratio of CBV lesion volume to CSF volume were significantly different between malignant and nonmalignant groups. The best predictor of a malignant course was the ratio of CBV lesion volume to CSF volume with a cut-off value of 0.92 (96.2% sensitivity, 96.2% specificity, 96.2% positive predictive value, and 96.2% negative predictive value).

Conclusions—

Based on admission native CT and perfusion CT measurements, the ratio of ischemic lesion volume to CSF volume predicts the development of malignant MCA infarction with higher accuracy than other known predictors, including ischemic lesion volume or clinical characteristics.






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30-Day Mortality and Readmission After Hemorrhagic Stroke Among Medicare Beneficiaries in Joint Comm

Background and Purpose—

Ischemic stroke patients treated at Joint Commission Primary Stroke Center (JC-PSC)-certified hospitals have better outcomes. Data reflecting the impact of JC-PSC status on outcomes after hemorrhagic stroke are limited. We determined whether 30-day mortality and readmission rates after hemorrhagic stroke differed for patients treated at JC-PSC–certified versus noncertified hospitals.

Methods—

The study included all fee-for-service Medicare beneficiaries aged 65 years or older with a primary discharge diagnosis of subarachnoid hemorrhage (SAH) or intracerebral hemorrhage (ICH) in 2006. Covariate-adjusted logistic and Cox proportional hazards regression assessed the effect of care at a JC-PSC–certified hospital on 30-day mortality and readmission.

Results—

There were 2305 SAH and 8708 ICH discharges from JC-PSC–certified hospitals and 3892 SAH and 22 564 ICH discharges from noncertified hospitals. Unadjusted in-hospital mortality (SAH: 27.5% versus 33.2%, P<0.0001; ICH: 27.9% versus 29.6%, P=0.003) and 30-day mortality (SAH: 35.1% versus 44.0%, P<0.0001; ICH: 39.8% versus 42.4%, P<0.0001) were lower in JC-PSC hospitals, but 30-day readmission rates were similar (SAH: 17.0% versus 17.0%, P=0.97; ICH: 16.0% versus 15.5%, P=0.29). Risk-adjusted 30-day mortality was 34% lower (odds ratio, 0.66; 95% confidence interval, 0.58–0.76) after SAH and 14% lower (odds ratio, 0.86; 95% confidence interval, 0.80–0.92) after ICH for patients discharged from JC-PSC–certified hospitals. There was no difference in 30-day risk-adjusted readmission rates for SAH or ICH based on JC-PSC status.

Conclusions—

Patients treated at JC-PSC–certified hospitals had lower risk-adjusted mortality rates for both SAH and ICH but similar 30-day readmission rates as compared with noncertified hospitals.






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Frontal and Temporal Microbleeds Are Related to Cognitive Function: The Radboud University Nijmegen

Background and Purpose—

Cerebral small vessel disease, including white matter lesions and lacunar infarcts, is related to cognitive impairment. Cerebral microbleeds (MBs) are increasingly being recognized as another manifestation of small vessel disease and are also related to cognitive function. However, it remains unclear whether this relation is independent of white matter lesions and lacunar infarcts and if location of MB plays a role. We investigated the relation between the presence, number, and location of MB and cognitive performance adjusted for white matter lesions and lacunar infarcts.

Methods—

Presence, number, and location of MB were rated on a gradient echo T2*-weighted MRI in 500 nondemented elderly patients with small vessel disease. Cognitive performance was assessed in different domains. Analyses were adjusted for age, sex, education, depressive symptoms, total brain volume, white matter lesion volume, and lacunar and territorial infarcts.

Results—

Mean age was 65.6 years (SD 8.8) and 57% were male. MBs were present in 10.4% of the participants. Subjects with MBs were significantly older, had a higher white matter lesion volume, and more lacunar infarcts (P<0.001). Presence and number of MBs were related to global cognitive function (β–0.10, P=0.008; β–0.20, P=0.002), psychomotor speed (β–0.10, P=0.012; β–0.19, P=0.006), and attention (β–0.10, P=0.02; β–0.205, P=0.001). The relations with cognitive performance were mainly driven by frontal, temporal, and strictly deep located MB.

Conclusions—

Frontal and temporal located MBs correlate with cognitive performance in nondemented elderly patients independent of coexisting other small vessel disease-related lesions. MBs are clinically not silent and may help to understand the role of vascular disease in cognitive decline.






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Risk Profile of Intracranial Aneurysms: Rupture Rate Is Not Constant After Formation [Original Contr

Background and Purpose—

Management of asymptomatic unruptured intracranial aneurysms remains controversial, and recent prospective follow-up studies showed that the rupture rate of small aneurysms is very low. These results are inconsistent with the finding that the majority of ruptured aneurysms in patients with subarachnoid hemorrhage are small.

Methods—

A Markov model was constructed to simulate the natural history of intracranial aneurysms. All epidemiological and statistical data obtained from the Portal Site of Official Statistics of Japan (e-Stat) were adjusted to the standardized age distribution. From the selected data of aneurysm formation, the prevalence of unruptured aneurysms was estimated as 1.45% and the incidence of subarachnoid hemorrhage calculated to be 19.7/100 000/year in the whole standardized population.

Results—

The function for rupture rate constant with time was first analyzed. Selected values for annual rupture rates of 0.3%, 0.5%, 0.7%, and 1.0% showed inconsistencies in the relationship between the prevalence of unruptured aneurysm and the incidence of subarachnoid hemorrhage. Next, the function for a short period of high risk followed by a long period of low risk was considered. Annual rupture rates of 0.5%, 0.7%, and 1.0% indicated epidemiological compatibility with additional early rupture rates of 20%, 15%, and 10%, respectively.

Conclusions—

This study suggests that some aneurysms bleed shortly after formation and thus are rarely detected as unruptured aneurysms. Most aneurysms without early rupture remain stable for the remainder of life through some healing process, and prophylactic treatment for incidentally identified small unruptured aneurysms has no rationale.






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Epidemiology and Outcomes of Fever Burden Among Patients With Acute Ischemic Stroke [Original Contri

Background and Purpose—

Although fever following ischemic stroke is common and has been associated with poor patient outcomes, little is known about which aspects of fever (eg, frequency, severity, or duration) are most associated with outcomes.

Methods—

We used data from a retrospective cohort of acute ischemic stroke patients who were admitted to 1 of 5 hospitals (1998–2003). A fever event was defined as a period with a temperature ≥100.0°F (37.8°C). Fever burden was defined as the maximum temperature (Tmax) minus 100.0°F, multiplied by the number of days with a fever. Fever burden (in degree-days) was categorized as low (0.1–2.0), medium (2.1–4.0), or high (≥4.0). Logistic regression was used to evaluate the adjusted association of any fever episode and fever burden with the combined outcome of in-hospital mortality or discharge to hospice.

Results—

Among 1361 stroke patients, 483 patients (35.5%) had ≥1 fever event. Among febrile patients, the median Tmax was 100.9°F (range, 100.0–106.6°F), 87% had ≤2 events and median total fever days was 2. Patients with any fever event had higher combined outcome rates after adjusting for demographics, stroke severity, and clinical characteristics: adjusted odds ratio (aOR), 2.7 (95% CI, 1.6–4.4). Higher fever burden was also associated with the combined outcome: high burden aOR, 6.7 (95% CI, 3.6–12.7); medium burden aOR, 3.9 (95% CI, 1.9–8.2); and low burden aOR, 1.2 (95%CI, 0.6–2.3) versus no fever.

Conclusions—

This study confirms that poststroke fever occurs commonly and demonstrates that patients with high fever burden have a 6-fold increased odds of death or discharge to hospice.






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Stroke Epidemiology, Patterns of Management, and Outcomes in Fortaleza, Brazil: A Hospital-Based Mul

Background and Purpose—

Little information exists on the epidemiology and patterns of treatment of patients admitted to Brazilian hospitals with stroke. Our objective was to describe the frequency of risk factors, patterns of management, and outcome of patients admitted with stroke in Fortaleza, the fifth largest city in Brazil.

Methods—

Data were prospectively collected from consecutive patients admitted to 19 hospitals in Fortaleza with a diagnosis of stroke or transient ischemic attack from June 2009 to October 2010.

Results—

We evaluated 2407 consecutive patients (mean age, 67.7±14.4 years; 51.8% females). Ischemic stroke was the most frequent subtype (72.9%) followed by intraparenchymal hemorrhage (15.2%), subarachnoid hemorrhage (6.0%), transient ischemic attack (3%), and undetermined stroke (2.9%). The median time from symptoms onset to hospital admission was 12.9 (3.8–32.5) hours. Hypertension was the most common risk factor. Only 1.1% of the patients with ischemic stroke received thrombolysis. The median time from hospital admission to neuroimaging was 3.4 (1.2–26.5) hours. In-hospital mortality was 20.9% and the frequency of modified Rankin Scale score ≤2 at discharge was less than 30%. Older age, prestroke disability, and having a depressed level of consciousness at admission were independent predictors of poor outcome; conversely, male gender was a predictor of good outcome.

Conclusions—

The prevalence of stroke risk factors and clinical presentation in our cohort were similar to previous series. Treatment with thrombolysis and functional independency after a stroke admission were infrequent. We also found long delays in hospital admission and in evaluation with neuroimaging and high in-hospital mortality.






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Abnormalities in thalamic neurophysiology in schizophrenia: Could psychosis be a result of potassium

Publication year: 2011
Source: Neuroscience & Biobehavioral Reviews, Available online 28 November 2011
Zoran Vukadinovic, Ivana Rosenzweig
Psychosis in schizophrenia is associated with source-monitoring deficits whereby self-initiated behaviors become attributed to outside sources. One of the proposed functions of the thalamus is to adjust sensory responsiveness in accordance with the behavioral contextual cues. The thalamus is markedly affected in schizophrenia, and thalamic dysfunction may here result in reduced ability to adjust sensory responsiveness to ongoing behavior. One of the ways in which the thalamus accomplishes the adjustment of sensory processing is by a neurophysiological shift to post-inhibitory burst firing mode prior to and during certain exploratory actions. Reduced amount of thalamic burst firing may result from increased neuronal excitability secondary to a reported potassium channel dysfunction in schizophrenia. Pharmacological agents that reduce the excitability of thalamic cells and thereby promote burst firing by and large tend to have antipsychotic effects

Highlights

► Schizophrenia may involve failure in internal monitoring of self-initiated motor outputs. The thalamus may be involved in monitoring of efferent cortical motor outputs. The thalamus has been found to be markedly affected in schizophrenia. The thalamus displays burst firing mode prior to exploratory behaviors. Pharmacological agents that promote burst firing in the thalamus may have antipsychotic effects





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Vega Science Trust: Videos científicos de qualidade

O Projeto Vega, hospedado na Florida State University, é uma fonte confiavel de vídeos científicos. Há várias categorias de filmes, algumas estão ilustradas abaixo:




Há uma série de palestras de Richard Feynman que vale a pena ver. A primeira, sobre fotons, pode ser vista aqui. Feynman, Premio Nobel de Física, é considerado um dos maiores palestrantes científicos:

"Feynman gives us not





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Sunday, November 27, 2011

Perspectivas e limitações da C&T no Brasil

Um título meio pomposo, e seguramente pretensioso, para uma análise de como estamos em termos da produção científica e da formação de doutores no Brasil.

Apresentei esta palestra originalmente na Faculdade de Medicina de Ribeirão Preto (USP) e com algumas modificações no instituto de Saúde Coletiva da UFBA.



Ou seja:
A produção científica brasileira internacionalmente indexada aumentou muito,





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Vascular imaging adds value in investigation of basal ganglia hemorrhage

Publication year: 2011
Source: Journal of Clinical Neuroscience, Available online 25 November 2011
Tianheng Zheng, Shaoshi Wang, Christen Barras, Stephen Davis, Bernard Yan
The risk of basal ganglia hemorrhage (BGH) increases in patients of older age and with hypertension. Current guidelines do not recommend routine vascular imaging. However, a proportion of patients with BGH have underlying vascular abnormalities, and these patients may require a different treatment approach. We aimed to assess the proportion of underlying vascular abnormalities in patients with BGH. In this retrospective study, we included all patients who presented with BGH between January 2007 and December 2009 at a single institution. The following data were collected: patient demographics, vascular risk factors, medications, volume of hematoma, CT scans, CT angiogram, magnetic resonance angiography and digital subtraction angiography. We determined the proportion of underlying vascular abnormalities and correlated these findings with risk factors for BGH. A total of 113 consecutive patients with BGH were identified, and vascular imaging was performed in 61. The median age was 62 years and 48 (78.7%) of these patients were male. Forty-two (68.9%) of 61 patients had hypertension. Positive vascular imaging findings were identified in eight of 61 patients (13.1%): three intracranial aneurysms, three cavernous malformations, one Moyamoya disease and one arteriovenous malformation. There were no significant associations between demographic features, vascular risk factors and the hematoma volume between patients with positive and negative vascular imaging. Specifically, an underlying vascular abnormality was not associated with age (⩾60 years, 6/36 patients had an underlying vascular abnormality, compared with 2/25 patients < 60 years;p = not significant [n.s.]). There was no relationship with hypertension (5/42 hypertensive patients and 3/19 normotensive patients (n.s.) had an underlying vascular abnormality). We concluded that there is a significant proportion of relevant underlying vascular abnormalities in patients with BGH. This likelihood is not predicted by risk factors such as hypertension and age. These findings indicate the importance of vascular imaging in patients with BGH who are not neurologically devastated.





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FASTER (Face, Arm, Speech, Time, Emergency Response): Experience of Central Coast Stroke Services im

Publication year: 2011
Source: Journal of Clinical Neuroscience, Available online 25 November 2011
W. O'Brien, D. Crimmins, W. Donaldson, R. Risti, T.A. Clarke, ...
Despite benefit in acute ischaemic stroke, less than 3% of patients receive tissue plasminogen activator (tPA) in Australia. The FASTER (Face, Arm, Speech, Time, Emergency Response) protocol was constructed to reduce pre-hospital and Emergency Department (ED) delays and improve access to thrombolysis. This study aimed to determine if introduction of the FASTER protocol increases use of tPA using a prospective pre- and post-intervention cohort design in a metropolitan hospital. A pre-hospital assessment tool was used by ambulance services to screen potential tPA candidates. The acute stroke team was contacted, hospital bypass allowed, triage and CT radiology alerted, and the patient rapidly assessed on arrival to ED. Data were collected prospectively during the first 6 months of the new pathway and compared to a 6-month period 12 months prior to protocol initiation. In the 6 months following protocol introduction, 115 patients presented within 24 hours of onset of an ischaemic stroke: 22 (19%) received thrombolysis, significantly greater than five (7%) of 67 patients over the control period,p = 0.03. Overall, 42 patients were referred via the FASTER pathway, with 21 of these receiving tPA (50%). One inpatient stroke was also treated. Only two referrals (<5%) were stroke mimics. Introduction of the FASTER pathway also significantly reduced time to thrombolysis and time to admission to the stroke unit. Therefore, fast-track referral of potential tPA patients involving the ambulance services and streamlined hospital assessment is effective and efficient in improving patient access to thrombolysis.





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Predictors of outcome in World Federation of Neurologic Surgeons grade V aneurysmal subarachnoid hem

Background: Only a small percentage of World Federation of Neurologic Surgeons grade V aneurysmal subarachnoid hemorrhage patients have a favorable outcome. The influence of clinical parameters on outcome was assessed. Methods: Retrospective evaluation of consecutive patients admitted from 2000–2007 with grade V subarachnoid hemorrhage at two institutions by evaluating, over time, the motor value of the Glasgow Coma Scale, effects of external ventricular drainage and rebleeding on outcome. Six-month outcome was assessed with the extended Glasgow Outcome Scale; favorable outcome was defined as good recovery or moderately disabled. Findings: Of 126 patients, 28 had absent brainstem reflexes, without improvement after external ventricular drainage. Rebleeding occurred in 26 patients, resulting in treatment withdrawal in 14. Only one patient had a favorable outcome after rebleeding. Of the 84 remaining patients, 61 improved at day 2 after subarachnoid hemorrhage to Glasgow Coma Scale motor value ≥4; 24 of these (39%) had a favorable outcome. All 23 patients with a Glasgow Coma Scale motor value ≤3 had an unfavorable outcome or died. Patients younger than 65 yrs of age had a better outcome (p < .03). Hydrocephalus was present in 71 of 84 patients. Favorable outcome was similar for patients with a positive external ventricular drainage response (8 of 28) as compared to no response to external ventricular drainage (12 of 43). Interpretation: The high rebleeding rate and subsequent poor outcome in World Federation of Neurologic Surgeons grade V patients warrants early treatment to secure the ruptured aneurysm. Favorable outcome was seen in 39% of patients with a Glasgow Coma Scale motor value ≥4 at day 2. In this study, patients with Glasgow Coma Scale motor value ≤3 at day 2 all had a very poor prognosis.





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The impact of cormorbid conditions on critical illness

Objective: To review the current knowledge of common comorbidities in the intensive care unit, including diabetes mellitus, chronic obstructive pulmonary disease, cancer, end-stage renal disease, end-stage liver disease, HIV infection, and obesity, with specific attention to epidemiology, contribution to diseases and outcomes, and the impact on treatments in these patients. Data Source: Review of the relevant medical literature for specific common comorbidities in the critically ill. Results: Critically ill patients are admitted to the intensive care unit for various reasons, and often the admission diagnosis is accompanied by a chronic comorbidity. Chronic comorbid conditions commonly seen in critically ill patients may influence the decision to provide intensive care unit care, decisions regarding types and intensity of intensive care unit treatment options, and outcomes. The presence of comorbid conditions may predispose patients to specific complications or forms of organ dysfunction. The impact of specific comorbidities varies among critically ill medical, surgical, and other populations, and outcomes associated with certain comorbidities have changed over time. Specifically, outcomes for patients with cancer and HIV have improved, likely related to advances in therapy. Overall, the negative impact of chronic comorbidity on survival in critical illness may be primarily influenced by the degree of organ dysfunction or the cumulative severity of multiple comorbidities. Conclusion: Chronic comorbid conditions are common in critically ill patients. Both the acute illness and the chronic conditions influence prognosis and optimal care delivery for these patients, particularly for adverse outcomes and complications influenced by comorbidities. Further work is needed to fully determine the individual and combined impact of chronic comorbidities on intensive care unit outcomes.





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Saturday, November 26, 2011

Lumbosacral spondyloptosis treated using partial reduction and pedicular transvertebral screw fixati

Journal of Neurosurgery: Spine, Volume 0, Issue 0, Page 1-4, Ahead of Print.
Spondyloptosis is complete dislocation of the L-5 vertebral body on the sacrum anteriorly. Its optimal treatment is still controversial. In particular, choosing the optimal surgical technique is difficult in the osteoporotic elderly patient given the high incidence of instrumentation failure, pseudarthrosis, progressive slippage, and severe sagittal imbalance. The authors of this report used partial reduction and pedicular transvertebral screw fixation of the lumbosacral junction for the treatment of spondyloptosis in an osteoporotic elderly patient.





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Do statins reduce the risk of aneurysm development: a case-control study

Journal of Neurosurgery, Volume 0, Issue 0, Page 1-5, Ahead of Print.
Object Recent studies in rats have demonstrated that statins may have an inhibitory effect on intracranial aneurysm (IA) development. The purpose of this study was to assess whether long-term statin use is associated with a reduced risk of IA formation in humans. Methods This was a single-center case-control study that included consecutive patients admitted to the authors' institution between January 1, 2005, and December 31, 2008. A case was defined as a patient with a cerebral angiography–confirmed diagnosis of IA. Three controls were matched to each case based on age, sex, and index year of hospital admission. The primary exposure of interest was cumulative statin use. Conditional logistic regression was used to assess the relationship between statin intake and incidence of IA. Results In total, 1200 patients were included in the study. No overall association was found between statin use and incidence of IA formation (OR 1.08, 95% CI 0.69–1.69), nor when dichotomized into hydrophilic and lipophilic user, or between short (≤12-month) and long (≥36-month) duration of intake. Hypertension and smoking significantly increased the risk of IA development (OR 4.02, 95% CI 2.49–6.45, and OR 1.67, 95% CI 1.02–2.72, respectively). Conclusions In contrast to recent experimental reports of the association between statins and a reduction of IA formation, the authors' findings suggest that in humans statins may have no significant beneficial effect on IA suppression.





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Friday, November 25, 2011

Playing Music Alters The Processing Of Multiple Sensory Stimuli In The Brain

Over the years pianists develop a particularly acute sense of the temporal correlation between the movements of the piano keys and the sound of the notes played. However, they are no better than non-musicians at assessing the synchronicity of lip movements and speech...





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Panel recommends that assisted suicide be legalised in Canada

Assisted suicide and voluntary euthanasia should be legalised in Canada, an expert panel set up by the Royal Society of Canada has concluded after a two year study."We are recommending that the...





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Thursday, November 24, 2011

How Schizophrenia Gene Linked To Psychiatric Disorders Impairs Brain Development

Researchers have discovered how the gene variant DISC1, which is linked to schizophrenia and other psychiatric disorders, impairs a particular signalling pathway in neurons that is crucial for normal brain development. Li-Huei Tsai, director of MIT's Picower Institute for Learning and Memory, and colleagues, write about their findings in the 17 November issue of the journal Neuron...





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Stroke Care Worse, Delayed for Blacks (CME/CE)

(MedPage Today) -- Racial disparities persist in treatment of acute ischemic stroke, with African Americans less often receiving top-line care, a study conducted in Michigan showed.





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Sedation for critically ill adults with severe traumatic brain injury: A systematic review of random

Objectives: To summarize randomized controlled trials on the effects of sedative agents on neurologic outcome, mortality, intracranial pressure, cerebral perfusion pressure, and adverse drug events in critically ill adults with severe traumatic brain injury. Data Sources: PubMed, MEDLINE, EMBASE, the Cochrane Database, Google Scholar, two clinical trials registries, personal files, and reference lists of included articles. Study Selection: Randomized controlled trials of propofol, ketamine, etomidate, and agents from the opioid, benzodiazepine, α-2 agonist, and antipsychotic drug classes for management of adult intensive care unit patients with severe traumatic brain injury. Data Extraction: In duplicate and independently, two investigators extracted data and evaluated methodologic quality and results. Data Synthesis: Among 1,892 citations, 13 randomized controlled trials enrolling 380 patients met inclusion criteria. Long-term sedation (≥24 hrs) was addressed in six studies, whereas a bolus dose, short infusion, or doubling of plasma drug concentration was investigated in remaining trials. Most trials did not describe baseline traumatic brain injury prognostic factors or important cointerventions. Eight trials possibly or definitely concealed allocation and six were blinded. Insufficient data exist regarding the effects of sedative agents on neurologic outcome or mortality. Although their effects are likely transient, bolus doses of opioids may increase intracranial pressure and decrease cerebral perfusion pressure. In one study, a long-term infusion of propofol vs. morphine was associated with a reduced requirement for intracranial pressure-lowering cointerventions and a lower intracranial pressure on the third day. Trials of propofol vs. midazolam and ketamine vs. sufentanil found no difference between agents in intracranial pressure and cerebral perfusion pressure. Conclusions: This systematic review found no convincing evidence that one sedative agent is more efficacious than another for improvement of patient-centered outcomes, intracranial pressure, or cerebral perfusion pressure in critically ill adults with severe traumatic brain injury. High bolus doses of opioids, however, have potentially deleterious effects on intracranial pressure and cerebral perfusion pressure. Adequately powered, high-quality, randomized controlled trials are urgently warranted.





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Wednesday, November 23, 2011

Stereotactic Radiosurgery of Cranial Arteriovenous Malformations and Dural Arteriovenous Fistulas

Cranial arteriovenous malformations (AVM) and cranial dural arteriovenous fistulas (AVF) carry a significant risk of morbidity and mortality when they hemorrhage. Current treatment options include surgery, embolization, radiosurgery, or a combination of these treatments. Radiosurgery is thought to reduce the risk hemorrhage in AVMs and AVFs by obliterating of the nidus of abnormal vasculature over the course of 2 to 3 years. Success in treating AVMs is variable depending on the volume of the lesion, the radiation dose, and the pattern of vascular supply and drainage. This article discusses the considerations for selecting radiosurgery as a treatment modality in patients who present with AVMs and AVFs.





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Surgical Treatment of Cranial Arteriovenous Malformations and Dural Arteriovenous Fistulas

Microsurgical resection remains the treatment of choice for more than half of all patients with arteriovenous malformations (AVMs). It reduces the treatment window to a span of a few weeks and is curative. Careful patient selection, meticulous surgical planning, and painstaking technical execution of surgery are typically rewarded with excellent outcomes. For dural arteriovenous fistulas (DAVFs), microsurgical obliteration is often reserved for cases in which endovascular therapy either cannot be pursued or fails. When performed, however, microsurgical obliteration of DAVFs is associated with excellent outcomes as well. This article reviews the current state of microsurgical treatment of AVMs and DAVFs.





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Endovascular Treatment of Cranial Arteriovenous Malformations and Dural Arteriovenous Fistulas

Pial arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs) are high-flow vascular lesions with abnormal communications between the arterial and venous system. AVMs are congenital lesions, whereas DAVFs are considered acquired lesions. Both can cause significant morbidity and mortality if they rupture and result in intracranial hemorrhage. The primary goal of treatment is to eliminate the risk of bleeding or at least decrease it. Because the epidemiology, clinical presentation, and classification of AVMs and DAVFs have been covered in previous articles in this issue, the authors only briefly touch on these subjects as they relate to endovascular treatment.





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Imaging of Cerebral Arteriovenous Malformations and Dural Arteriovenous Fistulas

Imaging plays a major role in the identification, grading, and treatment of cerebral arteriovenous malformations and cerebral dural arteriovenous fistulas. Digital subtraction angiography is the gold standard in the diagnosis and characterization of these vascular malformations, but advances in both magnetic resonance imaging and computed tomography, including advanced imaging techniques, have provided new tools for further characterizing these lesions as well as the surrounding brain structures that may be affected. This article discusses the role of conventional as well as advanced imaging modalities that are providing novel ways to characterize these vascular malformations.





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Classification Schemes for Arteriovenous Malformations

The wide variety of arteriovenous malformation (AVM) anatomy, size, location, and clinical presentation makes patient selection for surgery a difficult process. Neurosurgeons have identified key factors that determine the risks of surgery and then devised classification schemes that integrate these factors, predict surgical results, and help select patients for surgery. These classification schemes have value because they transform complex decisions into simpler algorithms. In this review, the important grading schemes that have contributed to management of patients with brain AVMs are described, and our current approach to patient selection is outlined.





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Arteriovenous Malformations: Epidemiology and Clinical Presentation

Arteriovenous malformations (AVMs) of the brain are relatively rare congenital developmental vascular lesions. They may cause hemorrhagic stroke, epilepsy, chronic headache, or focal neurologic deficits, and the incidence of asymptomatic AVMs is increasing due to widespread availability of noninvasive imaging methods. Since the most severe complication of an AVM is hemorrhagic stroke, most epidemiologic studies have concentrated on the hemorrhage risk and its risk factors. In this article, the authors discuss the epidemiology, presenting symptoms, and hemorrhage risk associated with brain AVMs.





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How Meditation Benefits The Brain

A new brain imaging study led by researchers at Yale University shows how people who regularly practise meditation are able to switch off areas of the brain linked to daydreaming, anxiety, schizophrenia and other psychiatric disorders...





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Incident Stroke and Mortality Associated With New-Onset Atrial Fibrillation in Patients Hospitalized

Context New-onset atrial fibrillation (AF) has been reported in 6% to 20% of patients with severe sepsis. Chronic AF is a known risk factor for stroke and death, but the clinical significance of new-onset AF in the setting of severe sepsis is uncertain.

Objective To determine the in-hospital stroke and in-hospital mortality risks associated with new-onset AF in patients with severe sepsis.

Design and Setting Retrospective population-based cohort of California State Inpatient Database administrative claims data from nonfederal acute care hospitals for January 1 through December 31, 2007.

Patients Data were available for 3 144 787 hospitalized adults. Severe sepsis (n = 49 082 [1.56%]) was defined by validated International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 995.92. New-onset AF was defined as AF that occurred during the hospital stay, after excluding AF cases present at admission.

Main Outcome Measures A priori outcome measures were in-hospital ischemic stroke (ICD-9-CM codes 433, 434, or 436) and mortality.

Results Patients with severe sepsis were a mean age of 69 (SD, 16) years and 48% were women. New-onset AF occurred in 5.9% of patients with severe sepsis vs 0.65% of patients without severe sepsis (multivariable-adjusted odds ratio [OR], 6.82; 95% CI, 6.54-7.11; P < .001). Severe sepsis was present in 14% of all new-onset AF in hospitalized adults. Compared with severe sepsis patients without new-onset AF, patients with new-onset AF during severe sepsis had greater risks of in-hospital stroke (75/2896 [2.6%] vs 306/46 186 [0.6%] strokes; adjusted OR, 2.70; 95% CI, 2.05-3.57; P < .001) and in-hospital mortality (1629 [56%] vs 18 027 [39%] deaths; adjusted relative risk, 1.07; 95% CI, 1.04-1.11; P < .001). Findings were robust across 2 definitions of severe sepsis, multiple methods of addressing confounding, and multiple sensitivity analyses.

Conclusion Among patients with severe sepsis, patients with new-onset AF were at increased risk of in-hospital stroke and death compared with patients with no AF and patients with preexisting AF.






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Tuesday, November 22, 2011

The practice of neurology, 2000-2010: Report of the AAN Member Research Subcommittee

Objective:

To present an analysis of American Academy of Neurology (AAN) membership demographics and practice trends over the past decade.

Methods:

Data from the 2009 AAN Census and 2010 Practice Profile Form (PPF) surveys were compared to results from 2004 and 2000 surveys. The Census was sent to all AAN members, and the PPF was sent to a random sample of US practicing neurologists.

Results:

Since 2000, AAN membership increased by 31%, and the number of US neurologist-members increased by 14%. Mean age of US neurologists increased from 48.6 to 53.3 years, and 23.9% of neurologists are women. There was a 15% increase in the proportion of neurologists relative to the US population, from 3.41 neurologists per 100,000 population in 2000 to 3.92 neurologists in 2009. In 2009, 24.1% of US neurologists were in solo practice, 27.8% were in a neurology group, and 35.6% were in multispecialty/university settings, with little change in practice arrangements over time. The top 5 practice interest areas were unchanged since 2004 as were the number of hours devoted to patient care (42.3) or total work hours per week (57.1). Little change was observed in performed procedures, except increased use of botulinum toxin and nerve blocks and a decline in lumbar punctures. Neurologists rely more on physician assistants to see follow-up and new patients independently (p < 0.001).

Conclusion:

Despite advances in neurologic diagnosis and therapy, there has been little change in practice characteristics of US neurologists.






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Thrombolysis outcomes in acute ischemic stroke patients with prior stroke and diabetes mellitus

Background:

Patients with concomitant diabetes mellitus (DM) and prior stroke (PS) were excluded from European approval of alteplase in stroke. We examined the influence of DM and PS on the outcomes of patients who received thrombolytic therapy (T; data from Safe Implementation of Thrombolysis in Stroke–International Stroke Thrombolysis Register) compared to nonthrombolyzed controls (C; data from Virtual International Stroke Trials Archive).

Methods:

We selected ischemic stroke patients on whom we held data on age, baseline NIH Stroke Scale score (NIHSS), and 90-day modified Rankin Scale score (mRS). We compared the distribution of mRS between T and C by Cochran-Mantel-Haenszel (CMH) test and proportional odds logistic regression, after adjustment for age and baseline NIHSS, in patients with and without DM, PS, or the combination. We report odds ratios (OR) for improved distribution of mRS with 95% confidence interval (CI) and CMH p value.

Results:

Data were available for 29,500 patients: 5,411 (18.5%) had DM, 5,019 had PS (17.1%), and 1,141 (5.5%) had both. Adjusted mRS outcomes were better for T vs C among patients with DM (OR 1.45 [1.30–1.62], n = 5,354), PS (OR 1.55 [1.40–1.72], n = 4,986), or concomitant DM and PS (OR 1.23 [0.996–1.52], p = 0.05, n = 1,136), all CMH p < 0.0001. These are comparable to outcomes between T and C among patients with neither DM nor PS: OR = 1.53 (1.42–1.63), p < 0.0001, n = 19,339. There was no interaction on outcome between DM and PS with alteplase treatment (tissue plasminogen activator x DM x PS, p = 0.5). Age ≤80 years or >80 years did not influence our findings.

Conclusions:

Outcomes from thrombolysis are better than the controls among patients with DM, PS, or both. We find no statistical justification for the exclusion of these patients from receiving thrombolytic therapy.






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Regeneration After A Stroke Requires Intact Communication Channels Between The Two Halves Of The Bra

The structure of the corpus callosum, a thick band of nerve fibres that connects the two halves of the brain with each other and in this way enables the rapid exchange of information between the left and right hemispheres, plays an important role in the regaining of motor skills following a stroke...





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Monday, November 21, 2011

Craniovertebral junction abnormalities with hindbrain herniation and syringomyelia: regression of sy

Journal of Neurosurgery, Volume 0, Issue 0, Page 1-9, Ahead of Print.
Object Hindbrain herniation syndrome, or Chiari malformation Type I (CM-I), occurs frequently with craniovertebral junction (CVJ) abnormalities when there is reduction in the posterior fossa volume. Syringomyelia is often present. Posterior fossa dorsal decompression (PFDD) is typically performed but has adverse results when ventral bone abnormality exists. This paper presents the results of a prospective study on CVJ abnormalities in patients with CM-I and syringomyelia. Methods Between 1984 and 2008 (the MR imaging era), 298 patients with CVJ abnormalities and CM-I underwent ventral cervicomedullary decompression. Eighty-four patients had associated syringomyelia (15 with secondary invagination and 69 with primary basilar invagination, os odontoideum, or malunion of fractures). Of these 84 patients with CVJ abnormalities, CM-I, and syringomyelia, 46 had previously undergone PFDD, and 28 had previously undergone PFDD combined with fusion procedures or shunt placements. Of the 84 patients, a cervicothoracic syrinx was observed in 57, thoracic syrinx in 14, and holocord syrinx in 13. Studies included CT, MR imaging, and cine flow studies. All 298 patients who underwent ventral CVJ decompression had irreducible or partially reducible pathology. All 84 with syringomyelia showed brainstem dysfunction, lower cranial nerve symptoms, or myelopathy. Results Brainstem signs improved in 66 of the 84 patients, myelopathy improved in 58, and syringomyelia regressed in 64. Conclusions Neurological improvement and syringomyelia resolution can occur using only ventral cervicomedullary junction decompression in patients with basilar invagination and basilar impression. This is likely due to the relief of neural encroachment and reestablishment of CSF pathways.





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