Weather conditions associated with subarachnoid hemorrhage: a multicenter case-crossover study.

BACKGROUND: Most spontaneous subarachnoid hemorrhages (SAH) occur unexpectedly and independently of classical risk factors. In the light of increasing climate variability and change, we investigated weather and rapid weather changes as possible short-term risk factors for SAH. METHODS: Seven hundred ninety one patients admitted to three major hospitals in Germany for non-traumatic SAH with a determinable onset of SAH symptoms were included in this hospital-based, case-crossover study. The effects of atmospheric pressure, relative air humidity, and ambient temperature and their 24 h changes on the onset of SAH under temperate climate conditions were estimated. RESULTS: There was no association between the risk of SAH and 24 h weather changes, mean daily temperature or mean relative air humidity in the overall population. For every 11.5 hPa higher mean daily atmospheric pressure, the risk of SAH increased by 15% (OR 1.15, 95% confidence interval (CI) 1.01-1.30) in the entire study population with a lag time of three days. CONCLUSION: Our results suggest no relevant association between 24 h-weather changes or absolute values of ambient temperature and relative humidity and the risk of SAH. The medical significance of the statistically weak increase in SAH risk three days after exposure to high atmospheric pressure is unclear. However, as the occurrence of stable high-pressure systems will increase with global warming and potentially affect SAH risk, we call for confirming studies in different geographical regions to verify our observations.

Characteristics in Non-Vitamin K Antagonist Oral Anticoagulant-Related Intracerebral Hemorrhage.

Background and Purpose- Given inconclusive studies, it is debated whether clinical and imaging characteristics, as well as functional outcome, differ among patients with intracerebral hemorrhage (ICH) related to vitamin K antagonists (VKA) versus non-vitamin K antagonist (NOAC)-related ICH. Notably, clinical characteristics according to different NOAC agents and dosages are not established. Methods- Multicenter observational cohort study integrating individual patient data of 1328 patients with oral anticoagulation-associated ICH, including 190 NOAC-related ICH patients, recruited from 2011 to 2015 at 19 tertiary centers across Germany. Imaging, clinical characteristics, and 3-months modified Rankin Scale (mRS) outcomes were compared in NOAC- versus VKA-related ICH patients. Propensity score matching was conducted to adjust for clinically relevant differences in baseline parameters. Subgroup analyses were performed regarding NOAC agent, dosing and present clinically relevant anticoagulatory activity (last intake <12h/24h or NOAC level >30 ng/mL). Results- Despite older age in NOAC patients, there were no relevant differences in clinical and hematoma characteristics between NOAC- and VKA-related ICH regarding baseline hematoma volume (median [interquartile range]: NOAC, 14.7 [5.1-42.3] mL versus VKA, 16.4 [5.8-40.6] mL; P=0.33), rate of hematoma expansion (NOAC, 49/146 [33.6%] versus VKA, 235/688 [34.2%]; P=0.89), and the proportion of patients with unfavorable outcome at 3 months (mRS, 4-6: NOAC 126/179 [70.4%] versus VKA 473/682 [69.4%]; P=0.79). Subgroup analyses revealed that NOAC patients with clinically relevant anticoagulatory effect had higher rates of intraventricular hemorrhage (n/N [%]: present 52/109 [47.7%] versus absent 9/35 [25.7%]; P=0.022) and hematoma expansion (present 35/90 [38.9%] versus absent 5/30 [16.7%]; P=0.040), whereas type of NOAC agent or different NOAC-dosing regimens did not result in relevant differences in imaging characteristics or outcome. Conclusions- If effectively anticoagulated, there are no differences in hematoma characteristics and functional outcome among patients with NOAC- or VKA-related ICH. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT03093233.

Heparin for prophylaxis of venous thromboembolism in intracerebral haemorrhage.

OBJECTIVE: To determine the occurrence of intracranial haemorrhagic complications (IHC) on heparin prophylaxis (low-dose subcutaneous heparin, LDSH) in primary spontaneous intracerebral haemorrhage (ICH) (not oral anticoagulation-associated ICH, non-OAC-ICH), vitamin K antagonist (VKA)-associated ICH and non-vitamin K antagonist oral anticoagulant (NOAC)-associated ICH. METHODS: Retrospective cohort study (RETRACE) of 22 participating centres and prospective single-centre study with 1702 patients with VKA-associated or NOAC-associated ICH and 1022 patients with non-OAC-ICH with heparin prophylaxis between 2006 and 2015. Outcomes were defined as rates of IHC during hospital stay among patients with non-OAC-ICH, VKA-ICH and NOAC-ICH, mortality and functional outcome at 3 months between patients with ICH with and without IHC. RESULTS: IHC occurred in 1.7% (42/2416) of patients with ICH. There were no differences in crude incidence rates among patients with VKA-ICH, NOAC-ICH and non-OAC-ICH (log-rank p=0.645; VKA-ICH: 27/1406 (1.9%), NOAC-ICH 1/130 (0.8%), non-OAC-ICH 14/880 (1.6%); p=0.577). Detailed analysis according to treatment exposure (days with and without LDSH) revealed no differences in incidence rates of IHC per 1000 patient-days (LDSH: 1.43 (1.04-1.93) vs non-LDSH: 1.32 (0.33-3.58), conditional maximum likelihood incidence rate ratio: 1.09 (0.38-4.43); p=0.953). Secondary outcomes showed differences in functional outcome (modified Rankin Scale=4-6: IHC: 29/37 (78.4%) vs non-IHC: 1213/2048 (59.2%); p=0.019) and mortality (IHC: 14/37 (37.8%) vs non-IHC: 485/2048 (23.7%); p=0.045) in disfavour of patients with IHC. Small ICH volume (OR: volume <4.4 mL: 0.18 (0.04-0.78); p=0.022) and low National Institutes of Health Stroke Scale (NIHSS) score on admission (OR: NIHSS <4: 0.29 (0.11-0.78); p=0.014) were significantly associated with fewer IHC. CONCLUSIONS: Heparin administration for venous thromboembolism (VTE) prophylaxis in patients with ICH appears to be safe regarding IHC among non-OAC-ICH, VKA-ICH and NOAC-ICH in this observational cohort analysis. Randomised controlled trials are needed to verify the safety and efficacy of heparin compared with other methods for VTE prevention.

Oral anticoagulation in patients with atrial fibrillation and acute ischaemic stroke: design and baseline data of the prospective multicentre Berlin Atrial Fibrillation Registry.

AIMS: The Berlin Atrial Fibrillation Registry was designed to analyse oral anticoagulation (OAC) prescription in patients with atrial fibrillation (AF) and acute ischaemic stroke. METHODS AND RESULTS: This investigator-initiated prospective multicentre registry enrolled patients at all 16 stroke units located in Berlin, Germany. The ongoing telephone follow-up is conducted centrally and will cover 5 years per patient. Within 2014 and 2016, 1080 patients gave written informed consent and 1048 patients were available for analysis. Median age was 77 years [interquartile range (IQR) 72-83], 503 (48%) patients were female, and 254 (24%) had a transient ischaemic attack (TIA). Overall, 470 (62%) out of 757 patients with known AF and a (pre-stroke) CHA2DS2-VASc ≥ 1 were anticoagulated at the time of stroke. At hospital discharge, 847 (81.3%) of 1042 patients were anticoagulated. Thereof 710 (68.1%) received a non-vitamin K-dependent oral anticoagulant (NOAC) and 137 (13.1%) a vitamin K antagonist (VKA). Pre-stroke intake of a NOAC [odds ratio (OR) 15.6 (95% confidence interval, 95% CI 1.97-122)] or VKA [OR 0.04 (95% CI 0.02-0.09)], an index TIA [OR 0.56 (95% CI 0.34-0.94)] rather than stroke, heart failure [OR 0.49 (95% CI 0.26-0.93)], and endovascular thrombectomy at hospital admission [OR 12.9 (95% CI 1.59-104)] were associated with NOAC prescription at discharge. Patients' age or AF type had no impact on OAC or NOAC use, respectively. CONCLUSION: About 60% of all registry patients with known AF received OAC at the time of stroke or TIA. At hospital discharge, more than 80% of AF patients were anticoagulated and about 80% of those were prescribed a NOAC.

Management of therapeutic anticoagulation in patients with intracerebral haemorrhage and mechanical heart valves.

Aims: Evidence is lacking regarding acute anticoagulation management in patients after intracerebral haemorrhage (ICH) with implanted mechanical heart valves (MHVs). Our objective was to investigate anticoagulation reversal and resumption strategies by evaluating incidences of haemorrhagic and thromboembolic complications, thereby defining an optimal time-window when to restart therapeutic anticoagulation (TA) in patients with MHV and ICH. Methods and results: We pooled individual patient-data (n = 2504) from a nationwide multicentre cohort-study (RETRACE, conducted at 22 German centres) and eventually identified MHV-patients (n = 137) with anticoagulation-associated ICH for outcome analyses. The primary outcome consisted of major haemorrhagic complications analysed during hospital stay according to treatment exposure (restarted TA vs. no-TA). Secondary outcomes comprised thromboembolic complications, the composite outcome (haemorrhagic and thromboembolic complications), timing of TA, and mortality. Adjusted analyses involved propensity-score matching and multivariable cox-regressions to identify optimal timing of TA. In 66/137 (48%) of patients TA was restarted, being associated with increased haemorrhagic (TA = 17/66 (26%) vs. no-TA = 4/71 (6%); P < 0.01) and a trend to decreased thromboembolic complications (TA = 1/66 (2%) vs. no-TA = 7/71 (10%); P = 0.06). Controlling treatment crossovers provided an incidence rate-ratio [hazard ratio (HR) 10.31, 95% confidence interval (CI) 3.67-35.70; P < 0.01] in disadvantage of TA for haemorrhagic complications. Analyses of TA-timing displayed significant harm until Day 13 after ICH (HR 7.06, 95% CI 2.33-21.37; P < 0.01). The hazard for the composite-balancing both complications, was increased for restarted TA until Day 6 (HR 2.51, 95% CI 1.10-5.70; P = 0.03). Conclusion: Restarting TA within less than 2 weeks after ICH in patients with MHV was associated with increased haemorrhagic complications. Optimal weighing-between least risks for thromboembolic and haemorrhagic complications-provided an earliest starting point of TA at Day 6, reserved only for patients at high thromboembolic risk.

Association of Surgical Hematoma Evacuation vs Conservative Treatment With Functional Outcome in Patients With Cerebellar Intracerebral Hemorrhage.

Importance: The association of surgical hematoma evacuation with clinical outcomes in patients with cerebellar intracerebral hemorrhage (ICH) has not been established. Objective: To determine the association of surgical hematoma evacuation with clinical outcomes in cerebellar ICH. Design, Setting, and Participants: Individual participant data (IPD) meta-analysis of 4 observational ICH studies incorporating 6580 patients treated at 64 hospitals across the United States and Germany (2006-2015). Exposure: Surgical hematoma evacuation vs conservative treatment. Main Outcomes and Measures: The primary outcome was functional disability evaluated by the modified Rankin Scale ([mRS] score range: 0, no functional deficit to 6, death) at 3 months; favorable (mRS, 0-3) vs unfavorable (mRS, 4-6). Secondary outcomes included survival at 3 months and at 12 months. Analyses included propensity score matching and covariate adjustment, and predicted probabilities were used to identify treatment-related cutoff values for cerebellar ICH. Results: Among 578 patients with cerebellar ICH, propensity score-matched groups included 152 patients with surgical hematoma evacuation vs 152 patients with conservative treatment (age, 68.9 vs 69.2 years; men, 55.9% vs 51.3%; prior anticoagulation, 60.5% vs 63.8%; and median ICH volume, 20.5 cm3 vs 18.8 cm3). After adjustment, surgical hematoma evacuation vs conservative treatment was not significantly associated with likelihood of better functional disability at 3 months (30.9% vs 35.5%; adjusted odds ratio [AOR], 0.94 [95% CI, 0.81 to 1.09], P = .43; adjusted risk difference [ARD], -3.7% [95% CI, -8.7% to 1.2%]) but was significantly associated with greater probability of survival at 3 months (78.3% vs 61.2%; AOR, 1.25 [95% CI, 1.07 to 1.45], P = .005; ARD, 18.5% [95% CI, 13.8% to 23.2%]) and at 12 months (71.7% vs 57.2%; AOR, 1.21 [95% CI, 1.03 to 1.42], P = .02; ARD, 17.0% [95% CI, 11.5% to 22.6%]). A volume range of 12 to 15 cm3 was identified; below this level, surgical hematoma evacuation was associated with lower likelihood of favorable functional outcome (volume ≤12 cm3, 30.6% vs 62.3% [P = .003]; ARD, -34.7% [-38.8% to -30.6%]; P value for interaction, .01), and above, it was associated with greater likelihood of survival (volume ≥15 cm3, 74.5% vs 45.1% [P < .001]; ARD, 28.2% [95% CI, 24.6% to 31.8%]; P value for interaction, .02). Conclusions and Relevance: Among patients with cerebellar ICH, surgical hematoma evacuation, compared with conservative treatment, was not associated with improved functional outcome. Given the null primary outcome, investigation is necessary to establish whether there are differing associations based on hematoma volume.

Weather, Weather Changes and the Risk of Bell's Palsy: A Multicenter Case-Crossover Study.

BACKGROUND: To evaluate if weather or changes in weather are risk factors for Bell's palsy (BP) as exposure to draught of cold air has been popularly associated with the occurrence of BP. METHODS: Using a multicenter hospital-based case-crossover study, we analyzed the association between ambient temperature, atmospheric pressure, relative air humidity or their 24 h changes and the risk for BP in 825 patients or subgroups. RESULTS: One day following a 24 h increase in atmospheric pressure of more than 6 hPa, the risk for BP increased by 35% (OR 1.35; 95% CI 1.03-1.78) in the overall population. The risk for BP more than doubled in patients with diabetes mellitus after rapid variations in ambient temperature, independent of the direction (temperature decrease > 2.25°C; OR 2.15; 95% CI 1.08-4.25; temperature increase between 0.75 and 2.25°C; OR 2.88; 95% CI 1.63-5.10). CONCLUSIONS: Our findings support the hypothesis of an association between certain weather conditions and the risk for BP with acute changes in atmospheric pressure and ambient temperature as the main risk factors. Additionally, contrasting results for risk of BP after temperature changes in the diabetic and non-diabetic subgroups support the paradigm of a diabetic facial palsy as a distinct disease entity.

Changes of individual BrainAGE during the course of the menstrual cycle.

Brain morphology varies during the course of the menstrual cycle, with increases in individual gray matter volume at the time of ovulation. This study implemented our previously presented BrainAGE framework to analyze short-term neuroanatomical changes in healthy young women due to hormonal changes during the menstrual cycle. The BrainAGE approach determines the complex multidimensional aging pattern within the whole brain by applying established kernel regression methods to anatomical brain MRIs. The "Brain Age Gap Estimation" (i.e., BrainAGE) score is then calculated as the difference between chronological age and estimated brain age. Eight women (21-31 years) completed three to four MRI scans during their menstrual cycle (i.e., at (t1) menses, (t2) time of ovulation, (t3) midluteal phase, (t4) next menses). Serum levels of estradiol and progesterone were evaluated at each scanning session. Individual BrainAGE scores significantly differed during the course of the menstrual cycle (p<0.05), with a significant decrease of -1.3 years at ovulation (p<0.05). Moreover, higher estradiol levels significantly correlated with lower BrainAGE scores (r=-0.42, p<0.05). In future, the BrainAGE approach may serve as a sensitive as well as easily implementable tool to further explore the short-term and maybe long-term effects of hormones on brain plasticity and its modulating effects in lifestyle-related diseases and dementia.

Anticoagulant reversal, blood pressure levels, and anticoagulant resumption in patients with anticoagulation-related intracerebral hemorrhage.

IMPORTANCE: Although use of oral anticoagulants (OACs) is increasing, there is a substantial lack of data on how to treat OAC-associated intracerebral hemorrhage (ICH). OBJECTIVE: To assess the association of anticoagulation reversal and blood pressure (BP) with hematoma enlargement and the effects of OAC resumption. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study at 19 German tertiary care centers (2006-2012) including 1176 individuals for analysis of long-term functional outcome, 853 for analysis of hematoma enlargement, and 719 for analysis of OAC resumption. EXPOSURES: Reversal of anticoagulation during acute phase, systolic BP at 4 hours, and reinitiation of OAC for long-term treatment. MAIN OUTCOMES AND MEASURES: Frequency of hematoma enlargement in relation to international normalized ratio (INR) and BP. Incidence analysis of ischemic and hemorrhagic events with or without OAC resumption. Factors associated with favorable (modified Rankin Scale score, 0-3) vs unfavorable functional outcome. RESULTS: Hemorrhage enlargement occurred in 307 of 853 patients (36.0%). Reduced rates of hematoma enlargement were associated with reversal of INR levels <1.3 within 4 hours after admission (43/217 [19.8%]) vs INR of ≥1.3 (264/636 [41.5%]; P < .001) and systolic BP <160 mm Hg at 4 hours (167/504 [33.1%]) vs ≥160 mm Hg (98/187 [52.4%]; P < .001). The combination of INR reversal <1.3 within 4 hours and systolic BP of <160 mm Hg at 4 hours was associated with lower rates of hematoma enlargement (35/193 [18.1%] vs 220/498 [44.2%] not achieving these values; OR, 0.28; 95% CI, 0.19-0.42; P < .001) and lower rates of in-hospital mortality (26/193 [13.5%] vs 103/498 [20.7%]; OR, 0.60; 95% CI, 0.37-0.95; P = .03). OAC was resumed in 172 of 719 survivors (23.9%). OAC resumption showed fewer ischemic complications (OAC: 9/172 [5.2%] vs no OAC: 82/547 [15.0%]; P < .001) and not significantly different hemorrhagic complications (OAC: 14/172 [8.1%] vs no OAC: 36/547 [6.6%]; P = .48). Propensity-matched survival analysis in patients with atrial fibrillation who restarted OAC showed a decreased HR of 0.258 (95% CI, 0.125-0.534; P < .001) for long-term mortality. Functional long-term outcome was unfavorable in 786 of 1083 patients (72.6%). CONCLUSIONS AND RELEVANCE: Among patients with OAC-associated ICH, reversal of INR <1.3 within 4 hours and systolic BP <160 mm Hg at 4 hours were associated with lower rates of hematoma enlargement, and resumption of OAC therapy was associated with lower risk of ischemic events. These findings require replication and assessment in prospective studies. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01829581.

Follow-up of Patients With Stroke Based on Opt-out Choice: Potential Approach for Acute Care Quality Registries or Observational Studies.

BACKGROUND AND OBJECTIVES: Restricting follow-up assessment of both interventional and observational studies to patients who provide informed consent introduces relevant selection bias-particularly by underrepresenting patients with neurologic communication deficits and impaired capacity to consent. Many patients who are initially unable to give consent may be willing to do so after recovery. Informing patients on study purposes and procedures with offering them the option of nonparticipation but not requesting explicit consent is called "opt-out" approach. We investigated whether an opt-out strategy yields meaningful follow-up rates in an acute stroke registry with an embedded controlled study. METHODS: The citywide Berlin-SPecific Acute Treatment in Ischemic or hAemorrhagic Stroke With Long Term Follow-up (B-SPATIAL) registry was designed to provide reliable information on process indicators and outcomes of specific acute stroke treatments to inform health care providers about quality of care and best practice strategies including the effects of a mobile stroke unit implementation. Because this information was regarded of high public interest, Berlin data protection authorities permitted data sampling without prior informed consent, using instead follow-up assessment on an "opt-out" basis. Patients were included if they had neurologic symptoms at ambulance or hospital arrival within 6 hours of onset and had a final diagnosis of stroke or TIA. Information on data collection and outcome assessment was sent by letter to patients 1 month before follow-up. RESULTS: From February 1, 2017, to January 31, 2020, a total of 10,597 patients were assessed. Thirty-one (0.3%) patients declined any data use, whereas 578 (5.5%) opted out of follow-up assessment. Of those not opting out (n = 9,988), functional outcome (modified Rankin Scale) was collected in 8,330 patients (83.4%) and vital status in 9,741 patients (97.5%). We received no complaints regarding data collection procedures. DISCUSSION: Opt-out-based follow-up collection offers a way to achieve high follow-up rates along with respecting patients' preferences.

Off-label-dosing of non-vitamin K-dependent oral antagonists in AF patients before and after stroke: results of the prospective multicenter Berlin Atrial Fibrillation Registry.

AIMS: We aimed to analyze prevalence and predictors of NOAC off-label under-dosing in AF patients before and after the index stroke. METHODS: The post hoc analysis included 1080 patients of the investigator-initiated, multicenter prospective Berlin Atrial Fibrillation Registry, designed to analyze medical stroke prevention in AF patients after acute ischemic stroke. RESULTS: At stroke onset, an off-label daily dose was prescribed in 61 (25.5%) of 239 NOAC patients with known AF and CHA2DS2-VASc score ≥ 1, of which 52 (21.8%) patients were under-dosed. Under-dosing was associated with age ≥ 80 years in patients on rivaroxaban [OR 2.90, 95% CI 1.05-7.9, P = 0.04; n = 29] or apixaban [OR 3.24, 95% CI 1.04-10.1, P = 0.04; n = 22]. At hospital discharge after the index stroke, NOAC off-label dose on admission was continued in 30 (49.2%) of 61 patients. Overall, 79 (13.7%) of 708 patients prescribed a NOAC at hospital discharge received an off-label dose, of whom 75 (10.6%) patients were under-dosed. Rivaroxaban under-dosing at discharge was associated with age ≥ 80 years [OR 3.49, 95% CI 1.24-9.84, P = 0.02; n = 19]; apixaban under-dosing with body weight ≤ 60 kg [OR 0.06, 95% CI 0.01-0.47, P < 0.01; n = 56], CHA2DS2-VASc score [OR per point 1.47, 95% CI 1.08-2.00, P = 0.01], and HAS-BLED score [OR per point 1.91, 95% CI 1.28-2.84, P < 0.01]. CONCLUSION: At stroke onset, off-label dosing was present in one out of four, and under-dosing in one out of five NOAC patients. Under-dosing of rivaroxaban or apixaban was related to old age. In-hospital treatment after stroke reduced off-label NOAC dosing, but one out of ten NOAC patients was under-dosed at discharge. CLINICAL TRIAL REGISTRATION: NCT02306824.

Central sleep apnea indicates autonomic dysfunction in asymptomatic carotid stenosis: a potential marker of cerebrovascular and cardiovascular risk.

STUDY OBJECTIVES: Arteriosclerosis related stenosis in the carotid bulb causes autonomic imbalance, likely due to carotid chemoreceptor and baroreceptor dysfunction. The latter are associated with increased cerebrovascular and cardiovascular mortality. Chemoreceptor and baroreceptor dysfunction is also involved in the origin of central sleep apnea syndrome (CSA) in different clinical entities. We hypothesized that CSA is associated with stenosis of the internal carotid artery (ICA). The mechanism of this association is an autonomic imbalance induced by stenosis-mediated chemoreceptor and baroreceptor dysfunction. DESIGN: Cross-sectional prospective study. SETTING: University-based tertiary referral sleep clinic and research center. PATIENTS: Fifty-nine patients with various degrees of asymptomatic extracranial ICA (elCA) (n = 49) and intracranial ICA (ilCA) stenosis (n = 10) were investigated. INTERVENTIONS: Polysomnography to detect CSA and analysis of spontaneous heart rate variability (HRV) to detect autonomic imbalance. MEASUREMENTS AND RESULTS: CSA occurred in 39% of the patients with elCA stenosis but was absent in patients with ilCA stenosis. CSA was present in patients with severe elCA stenosis of > or = 70% on one side. Independent predictors for CSA were severity of stenosis, asymmetric distribution of stenosis between both elCA and autonomic imbalance, namely a decrease of parasympathetic tone. The specific constellation of HRV-parameters indicated increased chemoreceptor sensitivity and impaired baroreflex sensitivity. CONCLUSIONS: CSA indicates autonomic dysfunction in patients with asymptomatic elCA stenosis. Detection of CSA may help to identify asymptomatic patients with an increased risk of cerebrovascular or cardiovascular events who particularly benefit from carotid revascularization.

Nocturnal groaning (catathrenia) and epilepsy.

We report the case of a patient with idiopathic generalized epilepsy who ten years after the onset of his epilepsy also developed recurring nocturnal paroxysmal episodes reminiscent of his seizure semiology. Video monitoring and polysomnography revealed episodes of nocturnal groaning. Escalation of antiepileptic treatment was avoided.

An Evaluation of Depth and Size Perception on a Spherical Fish Tank Virtual Reality Display.

Fish Tank Virtual Reality (FTVR) displays create a compelling 3D spatial effect by rendering to the perspective of the viewer with head-tracking. Combining FTVR with a spherical display enhances the 3D experience with unique properties of the spherical screen such as the enclosing shape, consistent curved surface, and borderless views from all angles around the display. The ability to generate a strong 3D effect on a spherical display with head-tracked rendering is promising for increasing user's performance in 3D tasks. An unanswered question is whether these natural affordances of spherical FTVR displays can improve spatial perception in comparison to traditional flat FTVR displays. To investigate this question, we conducted an experiment to see whether users can perceive the depth and size of virtual objects better on a spherical FTVR display compared to a flat FTVR display on two tasks. Using the spherical display, we found significantly that users had 1cm depth accuracy compared to 6.5cm accuracy using the flat display on a depth-ranking task. Likewise, their performance on a size-matching task was also significantly better with the size error of 2.3mm on the spherical display compared to 3.1mm on the flat display. Furthermore, the perception of size-constancy is stronger on the spherical display than the flat display. This study indicates that the natural affordances provided by the spherical form factor improve depth and size perception in 3D compared to a flat display. We believe that spherical FTVR displays have potential as a 3D virtual environment to provide better task performance for various 3D applications such as 3D designs, scientific visualizations, and virtual surgery.

Levetiracetam as a treatment option in non-convulsive status epilepticus.

Non-convulsive status epilepticus (NCSE) is characterized by continuous or recurrent, generalized or focal epileptiform activity on the electroencephalogram and diverse clinical symptoms with alterations of mental state and vigilance. NCSE is not rare but certainly under diagnosed. There is some debate about how aggressive NCSE should be treated, as high dose anticonvulsants maybe partially responsible for the morbidity and mortality of patients with NCSE. We hypothesized that levetiracetam (LEV) as a well tolerated, highly effective new anticonvulsant, may be a safe treatment option. We retrospectively analyzed all (8) patients with NCSE who received levetiracetam from our database, compared with 11 patients with NCSE treated with conventional intravenous status medication as controls. These eight patients showed a marked clinical improvement with final cessation of ictal EEG-activity and clinical symptoms of NCSE after initiation of LEV within 3 days (mean 1.5 days). The response to conventional treatment was similarly effective but there were severe side effects whereas no relevant side effects in the LEV-treated group were noticed. A long-term follow up (6-36 months from discharge) revealed six patients with a persisting reduction in seizure frequency on medication with LEV. One patient changed the anticonvulsive medication because of inefficacy and one died from other causes than epilepsy 2 months after discharge from hospital. We found no significant differences in hospitalisation time, time in intensive care unit and outcome between the LEV group and the control group. This retrospectively acquired data suggests that LEV may be a well tolerated, effective treatment option in NCSE. This highlights the need for a prospective controlled study to further elucidate the utility of LEV in the treatment of NCSE, particularly as an intravenous formulation is now available.

Delayed shrinkage of the brain after ischemic stroke: preliminary observations with voxel-guided morphometry.

BACKGROUND AND PURPOSE: The most important effect of cerebral ischemia is brain infarction. In this magnetic resonance imaging (MRI) study, the authors aimed at assessing postischemic brain atrophy. METHODS: Ten patients suffering from their first acute cerebral ischemia in the territory of the middle cerebral artery were studied retrospectively. Three-dimensional MRI volume scans were recorded in the acute and chronic stage after infarction and analyzed voxel by voxel intraindividually with the newly developed voxel-guided morphometry. RESULTS: Shrinkage of brain tissue was detected in all patients, not only in the perilesional cortical structures but also in contralateral homolog cortex areas and subcortically in the striatum and thalamus. This secondary shrinkage was not related to the size of the infarcts or to the clinical outcome of patients. CONCLUSIONS: Our study suggests that delayed brain atrophy after acute ischemic stroke involved areas anatomically connected with the ischemic brain lesion but nevertheless was accompanied by a simultaneous improvement of the neurological deficit.