The Stroke Data Bank: Design, Methods, and Baseline Characteristics

The National Institute of Neurological and Communicative Disorders and Stroke Initiated the Stroke Data Bank, which is a Multicenter Project to Prospectively Collect Data on the Clinical Course and Sequelae of Stroke. Additional Objectives Were to Provide Information that Would Enable a Standard Diagnostic Clinical Evaluation, to Identify Prognostic Factors, and to Provide Planning Data for Future Studies. a Brief Description of the Structure and Methods Precede the Baseline Characterization of 1,805 Patients Enrolled in the Stroke Data Bank between July 1983 and June 1986. Two Thirds of These Patients Were Admitted within 24 Hours after Stroke Onset. Medical History, Neurologic History, and Hospitalization Summaries Are Presented Separately for the Following Stroke Subtypes: Infarction, Unknown Cause; Embolism from Cardiac Source; Infarction Due to Atherosclerosis; Lacune; Parenchy-Matous or Intracerebral Hemorrhage; Subarachnoid Hemorrhage; and Other. the Utility and Limitations of These Data Are Discussed. © 1988 American Heart Association, Inc

Determinants of Early Recurrence of Cerebral Infarction: The Stroke Data Bank

We Studied 1,273 Patients with Ischemic Cerebral Infarction Who Were Entered into the Stroke Data Bank, a Prospective, Observational Study Involving Four University Hospitals and the Biometry and Field Studies Branch of the National Institute of Neurological Disorders and Stroke. Forty Patients Had Non-Iatrogenic Recurrent Stroke within 30 Days after the Index Cerebral Infarction. using Life Tables, the 30-Day Cumulative± SE Risk of Early Recurrence for All Infarctions Was 3.3±0.4%. the Risk of Early Recurrence Was Greatest for Atherothrombotic Infarction (7.9±2.2%, Eight of 113 Patients) and Least for Lacunar Infarction (2.2±1.2%, Eight of 337 Patients). Both Cardioembolic Infarction (4.3±0.9%, 10 of 246 Patients) and Infarction of Undetermined Cause (3.0±0.5%, 14 of 508 Patients) Had Intermediate Risks. History of Hypertension and Diabetes Mellitus, as Well as Diastolic Hypertension and Elevated Blood Sugar Concentration at Admission, Were Associated with Early Recurrence. Logistic Regression Analysis Estimated the Risk of Early Recurrence to Be 8.56% in Those with Coexisting Hypertension and a Glucose Concentration of 300 Mg/dl Versus 0.77% in the Absence of These Two Abnormalities. Early Recurrence Was Associated with Longer Median Duration of Initial Hospital Stay (27 vs.. 14 Days) and a Higher 30-Day Case—fatality Rate (20% vs.. 7.4%). Increased Weakness Scores Were Associated with Early Recurrent Stroke. Identification of the Determinants of Early Recurrent Stroke May Lead to Better Secondary Prevention and May Help Select High-Risk Patients for Further Study. © 1989 American Heart Association, Inc

Dementia in Stroke Survivors in the Stroke Data Bank Cohort: Prevalence, Incidence, Risk Factors, and Computed Tomographic Findings

We Determined the Prevalence of Dementia in 927 Patients with Acute Ischemic Stroke Aged ≥60 Years in the Stroke Data Bank Cohort based on the Examining Neurologist\u27s Best Judgment Diagnostic Agreement among Examiners Was 68% (K=0.34). of 726 Testable Patients, 116 (16%) Were Demented. Prevalence of Dementia Was Related to Age But Not to Sex, Race, Handedness, Educational Level, or Employment Status Before the Stroke. Previous Stroke and Previous Myocardial Infarction Were Related to Prevalence of Dementia Although Hypertension, Diabetes Mellitus, Atrial Fibrillation, and Previous Use of Antithrombotic Drugs Were Not Prevalence of Dementia Was Most Frequent in Patients with Infarcts Due to Large-Artery Atherosclerosis and in Those with Infarcts of Unknown Cause. Computed Tomographic Findings Related to Prevalence of Dementia Included Infarct Number, Infarct Site, and Cortical Atrophy. among 610 Patients Who Were Not Demented at Stroke Onset, We Used Methods of Survival Analysis to Determine the Incidence of Dementia Occurring during the 2-Year Follow-Up. Incidence of Dementia Was Related to Age But Not Sex. based on Logistic Regression Analysis, the Probability of New-Onset Dementia at 1 Year Was 5.4% for a Patient Aged 60 Years and 10.4% for a Patient Aged 90 Years. with a Multivariate Proportional Hazards Model, the Most Important Predictors of Incidence of Dementia Were a Previous Stroke and the Presence of Cortical Atrophy at Stroke Onset. © 1990 American Heart Association, Inc

Simulations of spectral lines from an eccentric precessing accretion disc

Two dimensional SPH simulations of a precessing accretion disc in a q=0.1 binary system (such as XTE J1118+480) reveal complex and continuously varying shape, kinematics, and dissipation. The stream-disc impact region and disc spiral density waves are prominent sources of energy dissipation.The dissipated energy is modulated on the period P_{sh} = ({P_{orb}}^{-1}-{P_{prec}}^{-1}^{-1} with which the orientation of the disc relative to the mass donor repeats. This superhump modulation in dissipation energy has a variation in amplitude of ~10% relative to the total dissipation energy and evolves, repeating exactly only after a full disc precession cycle. A sharp component in the light curve is associated with centrifugally expelled material falling back and impacting the disc. Synthetic trailed spectrograms reveal two distinct "S-wave" features, produced respectively by the stream gas and the disc gas at the stream-disc impact shock. These S-waves are non-sinusoidal, and evolve with disc precession phase. We identify the spiral density wave emission in the trailed spectrogram. Instantaneous Doppler maps show how the stream impact moves in velocity space during an orbit. In our maximum entropy Doppler tomogram the stream impact region emission is distorted, and the spiral density wave emission is uppressed. A significant radial velocity modulation of the whole line profile occurs on the disc precession period. We compare our SPH simulation with a simple 3D model: the former is appropriate for comparison with emission lines while the latter is preferable for skewed absorption lines from precessing discs.Comment: See http://physics.open.ac.uk/FHMR/ for associated movie (avi) files. The full paper is in MNRAS press. Limited disk space limit of 650k, hence low resolution figure file

Thalamic Stroke: Presentation and Prognosis of Infarcts and Hemorrhages

Thalamic Strokes in 62 Patients Selected from the Stroke Data Bank Were Studied to Determine Differences among 18 Infarctions (INF), 23 Localized Hemorrhages (ICH), and 21 Hematomas with Ventricular Extension (IVH). Stupor or Coma at Onset Occurred More Frequently in the IVH (62%) Than in the INF (6%) or ICH (13%) Groups and Was Reflected in Significantly Lower Median Glasgow Coma Scores in the IVH Group (7) Than in the INF (15) and ICH (14) Groups. Although Ocular Movements Were More Frequently Abnormal in the IVH Group Compared with the ICH and INF Groups, No Significant Differences Were Found in the Frequency of Motor or Sensory Deficits. among the 62 Strokes, 32 Had Restricted Lesions of the Posterolateral (N=9), Anterior (N=3), Paramedian (N=7), and Dorsal (N=13) Portions of the Thalamus. Differences in Consciousness and in Motor, Sensory, and Oculomotor Deficits Were Found among the Topographic Subgroups. Stroke-Related Deaths Occurred in 52% of IVH Cases, 13% of ICH Cases, and No Cases of INF. Median Lesion Volume as Detected with Computed Tomography Was Greater in Hemorrhages (INF, 2 Cm3; ICH, 10 Cm3; IVH, 16 Cm3), with Mortality Related to Increasing Hematoma Size. Coma, Glasgow Coma Score Lower Than 9, Weakness Score Greater Than 15 of a Possible 30, Abnormal Ocular Movements, and Fixed Pupils Were Also Associated with Stroke-Related Mortality. We Conclude that the Initial Neurologic Syndrome Does Not Discriminate Infarcts from Intrathalamic Hemorrhages. Ventricular Extension, However, Causes Significantly More Severe Deficits and Higher Mortality. © 1992 Arch Neurol All Rights Reserved

Stroke Recurrence within 2 Years after Ischemic Infarction

We Prospectively Studied Stroke Recurrence in 1,273 Patients with Ischemic Stroke Who Were Entered into the Stroke Data Bank. Median Follow-Up Was 13 Months. the 2-Year Cumulative Recurrence Rate among These Patients Was 14.1%. Age, Sex, Race, History of Hypertension, Atrial Fibrillation, or Transient Ischemic Attacks, and Stroke Location Were Not Associated with a Higher Risk of Stroke Recurrence. Patients with an Elevated Blood Pressure, an Abnormal Initial Computed Tomogram, or a History of Diabetes Mellitus Were at a Higher Risk of Stroke Recurrence. in Contrast, Patients with an Infarct of Unknown Cause Were at a Lower Risk of Stroke Recurrence Than Patients with a Denned Stroke Mechanism, Such as Lacune, Embolism, or Atherosclerosis. Amultivaria Te Model Suggests that Patients at the Lowest Risk for Stroke Recurrence Have a Low Diastolic Blood Pressure, No History of Stroke, No History of Diabetes Mellitus, and an Infarct of Unknown Cause. © 1991 American Heart Association, Inc

Early Clinical Differentiation of Cerebral Infarction from Severe Atherosclerotic Stenosis and Cardioembolism

Background and Purpose: Hyperacute Cerebral Infarction Trials Require Early Differentiation of Infarction Subtype. Our Aim Was to Determine Clinical Factors Predictive of Infarction Subtype from Data Collected in the Early Hours of Admission. Methods: using the 1,273 Patients Enrolled in the Stroke Data Bank, Stroke Risk Factors and Demographic, Clinical, and Radiological Features Were Compared between the 246 Cardioembolic and 113 Large-Vessel Atherosclerotic Cerebral Infarcts. Results: Stroke Data Bank Definitions Ensured More Transient Ischemic Attacks in Atherosclerotic Infarcts and More Cardiac Disease in Cardioembolic Infarcts, But the Diagnosis Was Distinguished Further using a Logistic Regression Model. Fractional Arm Weakness (Shoulder Different from Hand) (Odds Ratio 3.1, 95% Confidence Interval [CI] 1.6-5.8), Hypertension (Odds Ratio 2.8, CI 1.4-5.3), Diabetes (Odds Ratio 2.5, CI 1.2-5.1) and Male Gender (Odds Ratio=2.2, CI 1.2-4.1) Occurred More Frequently in Patients with Atherosclerotic Than Cardioembolic Infarcts. Reduced Consciousness (Odds Ratio=3.2, CI 1.4-7.3) Was More Frequent in Cardio embolism. for a Male Patient with Hypertension, Diabetes, and Fractional Arm Weakness, the Estimated Odds of an Atherosclerotic Infarction Were 47-Fold that of a Cardioembolic Infarction. Patients with Atherosclerotic Infarcts Were More Likely to Have a Fractional Arm Weakness Regardless of Infarct Size, Whereas, for Those with Cardioembolic Infarctions, Fractional Weakness Was More Frequent in Infarcts Less Than 20 Cc in Volume. Conclusions: Clinical Features that Are Observed at Stroke Onset Can Help Distinguish Cerebral Infarction Subtypes and May Allow for Early Stratification in Therapeutic Trials. © 1992 American Heart Association, Inc

Morning Increase in Onset of Ischemic Stroke

The Time of Onset of Ischemic Stroke Was Determined for 1,167 of 1,273 Patients during the Collection of Data by Four Academic Hospital Centers between June 30, 1983, and June 30, 1986. More Strokes Occurred in Awake Patients from 10:00 Am to Noon Than during Any Other 2-Hour Interval. the Incidence of Stroke Onset Declined Steadily during the Remainder of the Day and Early Evening. the Onset of Stroke is Least Likely to Occur in the Late Evening, Before Midnight. © 1989 American Heart Association, Inc

Computational Complexity in Electronic Structure

In quantum chemistry, the price paid by all known efficient model chemistries is either the truncation of the Hilbert space or uncontrolled approximations. Theoretical computer science suggests that these restrictions are not mere shortcomings of the algorithm designers and programmers but could stem from the inherent difficulty of simulating quantum systems. Extensions of computer science and information processing exploiting quantum mechanics has led to new ways of understanding the ultimate limitations of computational power. Interestingly, this perspective helps us understand widely used model chemistries in a new light. In this article, the fundamentals of computational complexity will be reviewed and motivated from the vantage point of chemistry. Then recent results from the computational complexity literature regarding common model chemistries including Hartree-Fock and density functional theory are discussed.Comment: 14 pages, 2 figures, 1 table. Comments welcom