Transient Neurological Events Research Articles

Abstract WMP14: Cerebrospinal Fluid Beta-Amyloid Concentration and MRI Manifestations of Cerebral Amyloid Angiopathy

Background: Cerebral amyloid angiopathy (CAA) is associated with reduced cerebrospinal fluid (CSF) levels of the beta-amyloid (Aβ) 40- and 42-amino acid species, thought to reflect the burden of vascular Aβ deposition in the brain. Little is known regarding the association of CSF Aβ reduction with specific MRI manifestations of CAA. Methods: We identified 31 patients with CAA per Boston criteria v2.0 (1 definite, 27 probable, and 3 possible), who underwent CSF sampling for measurement of Aβ42, total tau (t-tau), and phospho-tau (p-tau) as part of their evaluation with ADmark (Athena Diagnostics). We assessed the following MRI manifestations of CAA while blinded to CSF biomarkers: the presence of cortical superficial siderosis (cSS), number of lobar cerebral microbleeds (CMBs), pattern and severity of white matter hyperintensities (WMH), and number of enlarged perivascular spaces in centrum semiovale (CSO-EPVS). Results: Median age of presentation was 69 years (range 56-89). Out of 31 patients, 19 were female (61.3%), 20 (64.5%) presented with cognitive impairment, 9 (29%) with intracerebral hemorrhage, and 2 (6.5%) with transient focal neurologic events. Mean (±SD) CSF Aβ42 concentration in our cohort was 359.3±126.7 pg/ml, substantially reduced relative to that reported in healthy controls. MRI manifestations associated with reduced Aβ42 without altered tau were presence of cSS (310±136 vs. 406±101, p=0.03) and higher burden of CSO-EPVS (307±101 vs. 431±127, p=0.005). Patients presented with cognitive impairment had higher tau levels (t-tau: 551±320 vs. 317±141, p=0.03; p-tau: 75.7±39.8 vs. 49.2±22.4, p=0.05) without altered Aβ42. Similar results were obtained when patients with possible CAA were excluded. Discussion: Our results suggest that presence of cSS and higher burden of CSO-EPVS are associated with lower Aβ42 concentration in CSF, potentially reflecting higher overall burden of vascular Aβ deposition in the brain. We found that higher tau concentrations in CSF are associated with cognitive impairment, presumably reflecting concomitant Alzheimer’s disease pathology. These results help inform interpretation of this clinically accessible test in practice and suggest potential mechanisms for specific CAA-related pathologies.

ABO blood types may affect transient neurological events after surgical revascularization in patients with moyamoya disease: a retrospective single center study

BackgroundMoyamoya disease (MMD) is a cerebrovascular disease with unknown cause. Patients with MMD disease usually experience transient neurological events (TNEs) after revascularization surgery. This retrospective single-center study was aimed to explore the risk factors of postoperative TNEs after surgical revascularization in patients with MMD.MethodsWe selected 324 patients who underwent surgical revascularization between January 2017 and September 2022 in our center. The perioperative characteristics of the patients were recorded and the outcome was TNEs after surgery. An analysis of risk factors contributing to postoperative TNEs by using logistic regression model.ResultsThree hundred twelve patients were enrolled, and the incidence of postoperative TNEs was 34% in our study. Males were more likely to suffer from postoperative TNEs (OR = 2.344, p = 0.002). Preoperative ischemic presentation (OR = 1.849, p = 0.048) and intraoperative hypotension (OR = 2.332, p = 0.002) were associated with postoperative TNEs. Compared to patients with blood type O, patients with blood type A (OR = 2.325, p = 0.028), B (OR = 2.239, p = 0.027) and AB (OR = 2.938, p = 0.019) had a significantly higher incidence of postoperative TNEs. A risk prediction model for postoperative TNEs was established, and the established risk prediction area under the receiver operating characteristic curve (ROC) of the model was 0.741.ConclusionsMales, preoperative ischemic presentation and intraoperative hypotension were associated with postoperative TNEs. We also found a possible link between postoperative TNEs and ABO blood types after surgical revascularization for moyamoya patients.

Inhalational Anesthesia Reduced Transient Neurological Events After Revascularization Surgery for Moyamoya Disease

BACKGROUND AND OBJECTIVES: The choice between inhalational and total intravenous anesthesia (TIVA) in revascularization surgery for Moyamoya disease (MMD) remains a topic of debate. Anesthesia methods have changed with the advent of new anesthetics. This study investigated whether modern anesthesia methods affected the development of neurological symptoms after revascularization surgery for MMD. METHODS: This single-center retrospective study included 63 adult patients (82 hemispheres) with MMD treated with direct and indirect bypass surgeries at our hospital between 2013 and 2022. Patients were divided into inhalational anesthesia (IA) and TIVA groups based on the anesthesia maintenance method. Baseline patient characteristics; postoperative neurological symptoms, including hyperperfusion syndrome, cerebral infarction, and transient neurological events (TNEs); and cortical hyperintensity belt (CHB) sign scores (5-point scale from 0 to 4) on postoperative magnetic resonance imaging were compared between the two groups. The operation methods, anesthetics, and intraoperative hemodynamic and ventilatory parameters were compared between patients with and without TNEs. RESULTS: The IA and TIVA groups comprised 39 and 43 hemispheres, respectively. The frequency of postoperative hyperperfusion syndrome and cerebral infarction did not differ between the groups, but the number of TNEs in the IA group (5/39; 13%) was significantly lower than that in the TIVA group (16/43; 37%). Multivariate logistic regression analysis revealed that TNEs were associated with TIVA (odds ratio, 3.91; 95% CI, 1.24-12.35; P = .02). The median [IQR] postoperative CHB sign score in the IA group (2 [1-3]) was significantly lower than that in the TIVA group (4 [3-4]). CONCLUSION: The IA group had fewer postoperative TNEs and lower CHB sign scores than the TIVA group. Although further studies are needed, this study provides insights into the prevention of TNEs with IA and reconsideration of the optimal anesthesia for MMD.

Presenting Symptoms and Diffusion-Weighted MRI Positivity by Time After Transient Neurologic Events: A Pooled Analysis of 3 Cohort Studies

The association between focal vs nonfocal presenting symptom and diffusion-weighted imaging (DWI) positivity in relation to onset-to-imaging time in patients with transient neurologic events remains unclear. We hypothesize that episodes consisting of focal symptoms would have proportionally higher DWI-positive imaging at later onset-to-imaging times. Patients with transient neurologic symptoms and a normal neurologic examination who had DWI in the combined data set of 3 cohort studies were included. We used logistic regression models to evaluate the association between each type of presenting symptom (motor weakness, speech impairment, sensory symptoms, vision loss, diplopia, gait instability, dizziness, headache, presyncope, and amnesia) and DWI positivity after adjusting for clinical variables (age, sex, history of stroke, dyslipidemia, coronary artery disease, atrial fibrillation, symptoms duration [<10, 10-59, ≥60 minutes, or unclear], and study source). We stratified the results by onset-to-imaging time categories (<6 hours, 6-23 hours, and ≥24 hours). Of the total 2,411 patients (1,345 male, median age 68 years), DWI-positive lesions were detected in 598 patients (24.8%). The prevalence of DWI positivity was highest in those with motor weakness (34.7%), followed by speech impairment (33.5%). In a multivariable analysis, the presence of motor weakness, speech impairment, and sensory symptoms was associated with DWI positivity, while vision loss and headache were associated with lower odds of DWI positivity, but nevertheless had 13.6% and 15.3% frequency of DWI positive. The odds of being DWI positive varied by onset-to-imaging time categories for motor weakness, with greater odds of being DWI positive at later imaging time (<6 hours: odds ratio [OR] 1.25, 95% confidence interval [CI] 0.84-1.87; 6-23 hours: OR 2.24, 95% CI 1.47-3.42; and ≥24 hours: OR 2.42, 95% CI 1.74-3.36; interaction p = 0.033). Associations of other symptoms with DWI positivity did not vary significantly by time categories. We found that onset-to-imaging time influences the relationship between motor weakness and DWI positivity in patients with transient neurologic events. Compared with motor, speech, and sensory symptoms, visual or nonfocal symptoms carry a lower but still a substantive association with DWI positivity.

Flow volume mismatch dramatically affects transient neurologic symptoms after direct bypass in Moyamoya disease.

Transient neurological events (TNEs) occur after bypass surgery in Moyamoya disease (MMD); however, their pathology remains unknown. To elucidate the pathophysiology of TNEs, we investigated their relationship with perioperative superficial temporal artery (STA) blood flow volume, which was evaluated using ultrasonography. Forty-nine patients with MMD, who underwent direct bypass surgery, were included and stratified into TNE and non-TNE groups, respectively. The STA blood flow volume was evaluated at four time points (preoperatively and 2-4, 7, and 10-14days postoperatively), and a change in volume during the postoperative period was defined as a flow volume mismatch. We investigated the association between ultrasonographic findings of flow volume mismatch and TNEs and magnetic resonance imaging findings, such as the cortical hyperintensity belt (CHB) sign, using univariate and path analyses. The STA blood flow volume increased immediately postoperatively, gradually decreasing over time, in both groups. The TNE group showed a significant increase in blood flow volume 2-4days postoperatively (P = 0.042). Flow volume mismatch was significantly larger in the TNE group than in the non-TNE group (P = 0.020). In the path analysis, STA flow volume mismatch showed a positive association with the CHB sign (P = 0.023) and TNEs (P = 0.000). Additionally, the CHB sign partially mediated the association between STA flow volume mismatch and TNEs. These results suggest that significantly high STA blood flow volume changes occurring during the acute postoperative period after direct bypass surgery in MMD are correlated with TNEs and the CHB sign, suggesting involvement in the pathophysiology of TNEs.

Effect of thin-split encephalomyosynangiosis on transient neurological events in revascularization surgery for pediatric patients with moyamoya disease.

Transient neurological events (TNEs) are among the most important events after revascularization surgery in pediatric patients with moyamoya disease (MMD). Although hemodynamic changes and crying are representative factors of TNEs, brain compression by encephalomyosynangiosis (EMS) is another important cause of TNEs. Therefore, the authors assumed that making the EMS as thin as possible reduces the frequency of TNEs. However, thin-split EMS can lead to insufficient development of collateral vessels. This study aimed to evaluate the effects of thin-split EMS in combined revascularization surgery on postoperative outcomes in pediatric patients with MMD. The authors retrospectively included 56 consecutive combined revascularization surgeries in the anterior cerebral circulation in pediatric patients with MMD. These surgeries were classified into the former group and thin-split EMS group. The temporal muscle was halved in the former EMS group and split as thinly as possible in the thin-split EMS group. The authors performed between-group comparisons of postoperative stroke events and TNEs during the acute period and the development of collateral flow and stroke events during the chronic period. Former and thin-split EMS procedures were performed in 37 and 19 patients, respectively. TNEs without crying or hemodynamic changes were observed significantly less frequently in the thin-split EMS group than in the former EMS group (0 [0.0%] in the thin-split EMS group vs 9 [24.3%] in the former EMS group, p = 0.021). There were no significant between-group differences in the development of indirect bypass during the chronic period (good: 34 [91.9%] and poor: 3 [8.1%] in the former EMS group vs good: 16 [84.2%] and poor: 3 [15.8%] in the thin-split EMS group; p = 0.397). Additionally, there were no significant between-group differences in the incidence of chronic clinical events, including death or stroke. Thin-split EMS can reduce TNEs that do not accompany crying or hemodynamic changes. Furthermore, the procedure has sufficient prevention effects against stroke events during the chronic postoperative period in pediatric patients with MMD.

Design, implementation, and preliminary in-vivo assessment of a high-CMRR low-NEF wireless EEG miniaturized platform.

This work presents the design, manufacture, test, and preliminary in-vivo assessment of the proof-of-concept of a miniaturized wireless platform for acquiring electroencephalography signals, where the input stage is a high-CMRR current-efficiency custom-made integrated neural preamplifier.Clinical relevance- Small, low-power consumption, wireless, wearable devices for chronically monitoring EEG recordings may contribute to the diagnosis of transient neurological events, the characterization and potential forecasting of epileptic seizures, and provide signals for controlling prosthetic and aid devices.

Chronological Volume Changes of the Temporal Muscle Pedicle Used for Encephalo-myo-synangiosis in Combined Revascularization for Moyamoya Disease: A Prospective Observational Study.

Although postoperative neurological events due to brain compression by the swollen temporal muscle are a rare complication, the chronological volume changes of the temporal muscle pedicle and their clinical impact have not yet been documented. This prospective observational study aimed to investigate the chronological volume changes in the temporal muscle pedicle in Moyamoya disease (MMD). Eighteen consecutive combined revascularization procedures using the temporal muscle were performed for symptomatic MMD in 2021. The postoperative pedicle volume was quantified using repeated computed tomography images on postoperative days (PODs) 0, 1, 7, 14, and 30. Postoperative neurological events with radiological evaluations and collateral development evaluated using magnetic resonance angiography obtained 6 months after surgery were studied. On average, the postoperative temporal muscle pedicle volume was most significantly increased by as much as 112% ± 9.6% on POD 7 (P < 0.001) and decreased by as little as 52% ± 21% on POD 30 (P < 0.0001) relative to POD 0. One exceptional patient (overall incidence, 5.6%) demonstrated postoperative transient neurological events due to brain compression by the swollen temporal muscle with decreased focal cerebral blood flow in the adjacent cortical area. The postoperative collateral development via direct and indirect revascularizations was confirmed in 16 (89%) and 12 (67%) hemispheres, respectively. All patients, except for one rebleeding case, showed independent outcomes at the mean latest follow-up period on 290 ± 96 days after surgery. Our observations confirmed the temporal profile of muscle pedicle volume changes after combined revascularization. Through routine attempts to avoid the unfavorable effects of temporal muscle swelling, combined revascularization can provide favorable outcomes in symptomatic MMD.

Effects of superficial temporal artery to middle cerebral artery bypass on postoperative infarction rates among young children (≤ 5 years old) with moyamoya disease

Revascularization surgery for young children with moyamoya disease (MMD) is challenging. Although indirect revascularization is preferred because of the technical difficulty in direct anastomosis, higher risks of postoperative infarction remain a problem. We aimed to investigate the effect of superficial temporal artery to middle cerebral artery (STA-MCA) bypass on postoperative outcomes during the acute postoperative period in young children ≤ 5years old with MMD. This retrospective study included consecutive young children with MMD who underwent surgical revascularization of the anterior cerebral circulation. Groups were determined according to the procedures performed, namely, the combined (STA-MCA bypass with indirect revascularization) and the indirect revascularization groups. The incidences of radiological or symptomatic infarction, transient neurological events, and new neurological deficits that remained at discharge were compared between groups. Of 38 surgical procedures, there were 23 combined and 15 indirect revascularizations. The median age of the patients was 3.0years, which was significantly different between groups (P < .01). When comparing the postoperative outcomes between groups, the incidences of radiological and symptomatic infarction and new neurological deficits that remained at discharge were significantly lower in the combined revascularization group (P < .05). Logistic regression analysis adjusted for potential confounders found that surgical modality was a statistically significant independent risk factor associated with radiological and symptomatic infarctions (indirect/combined, odds ratio: 10.2; 95% confidence interval: 1.30-79.7; P < .05). STA-MCA bypass combined with indirect revascularization can reduce the incidence of postoperative infarction in young children with MMD and might lead to better neurological outcomes.

Same-day versus staged revascularization of bilateral moyamoya arteriopathy in pediatric patients.

To compare the outcomes of conducting left and right hemisphere surgical revascularization on the same day versus different days for bilateral pediatric moyamoya arteriopathy patients. We retrospectively analyzed mortality, stroke, and transient neurologic event (TNE) rates in North American bilateral pediatric moyamoya arteriopathy patients who underwent bilateral cerebral revascularization. A total of 38 pediatric (≤ 18years old) patients at our institution underwent bilateral cerebral revascularization for moyamoya arteriopathy. Of these patients, 24 (63.2%) had both operations on the same day and 14 (36.8%) had the two operations on different days. The average length of stay for patients who underwent same-day bilateral revascularization was 6.9 ± 2.0days and the average length of stay for each operation for patients who underwent staged bilateral revascularization was 4.5 ± 1.4days, p = 0.001. While there were 7 (14.6%) postoperative strokes in patients who had both hemispheres revascularized on the same day, 0 (0%) strokes occurred in hemispheres after they had been operated on in the staged cohort, p = 0.042. Additionally, the postoperative stroke-free survival time in the ipsilateral hemisphere and TNE-free survival time were significantly longer in patients in the staged revascularization cohort. Same-day bilateral revascularization was associated with longer length of stay per operation, higher rate of ipsilateral stroke, and shorter postoperative TNE-free and stroke-free survival time in the revascularized hemisphere.

Safety of COVID-19 vaccines in multiple sclerosis: A systematic review and meta-analysis

Background Data are sparse regarding the safety of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in patients with multiple sclerosis (MS). Objective To estimate (1) the pooled proportion of MS patients experiencing relapse among vaccine recipients; (2) the rate of transient neurological worsening, adverse events, and serious adverse events; (3) the previous outcomes of interest for different SARS-CoV-2 vaccine types. Methods Systematic review and meta-analysis of pharmacovigilance registries and observational studies. Results Nineteen observational studies comprising 14,755 MS patients who received 23,088 doses of COVID-19 vaccines were included. Mean age was 43.3 years (95% confidence interval (CI): 40–46.6); relapsing-remitting, secondary-progressive, primary-progressive MS and clinically isolated syndrome were diagnosed in 82.6% (95% CI: 73.9–89.8), 12.6% (95% CI: 6.3–20.8), 6.7% (95% CI: 4.2–9.9), and 2.9% (95% CI: 1–5.9) of cases, respectively. The pooled proportion of MS patients experiencing relapse at a mean time interval of 20 days (95% CI: 12–28.2) from vaccination was 1.9% (95% CI: 1.3%–2.6%; I2 = 78%), with the relapse risk being independent of the type of administered SARS-CoV-2-vaccine (p for subgroup differences = 0.7 for messenger RNA (mRNA), inactivated virus, and adenovector-based vaccines). After vaccination, transient neurological worsening was observed in 4.8% (95% CI: 2.3%–8.1%) of patients. Adverse events and serious adverse events were reported in 52.8% (95% CI: 46.7%–58.8%) and 0.1% (95% CI: 0%–0.2%) of vaccinations, respectively. Conclusion COVID-19 vaccination does not appear to increase the risk of relapse and serious adverse events in MS. Weighted against the risks of SARS-CoV-2-related complications and MS exacerbations, these safety data provide compelling pro-vaccination arguments for MS patients.

Transient neurological events in childhood moyamoya disease.

Patients sometimes experience transient neurological events (TNEs) during the early postoperative period after revascularization surgery for childhood moyamoya disease. The clinical background and pathophysiology of TNEs remain unclear. This study aimed to evaluate the incidence rate of TNEs and discuss the factors associated with pediatric moyamoya disease. The authors retrospectively reviewed 110 cerebral hemispheres of 61 pediatric patients younger than 15 years who were treated from 2011 to 2020. All children underwent either simple double-direct or combined revascularization surgery. Of these 61 patients, 52 underwent bilateral surgery and 9 underwent unilateral surgery. The authors calculated the incidence of TNEs in accordance with a previously reported TNE definition. Cerebral blood flow (CBF) was evaluated in all eligible cases with xenon CT immediately after revascularization surgery. The incidence rate of TNEs in patients with childhood moyamoya disease was 26.4%. TNEs occurred after an average (range) of 6.26 (2-12) days postoperatively without triggers, and all identified TNEs spontaneously resolved within 2 weeks. The most common symptoms were dysarthria, facial palsy, and numbness around the mouth, followed by sensory disturbance of the upper extremities. The presence of focal hyperperfusion on xenon CT performed immediately after revascularization surgery was strongly correlated with the incidence of TNEs (p = 0.0001). Focal hyperperfusion was observed in 43 of 110 operative sides (39.1%). Notably, only 25.6% of patients with focal hyperperfusion showed numerical global hyperperfusion. In addition, a decrease in CBF compared with the thalamic region in the contralateral side was observed in TNE-affected cases (p = 0.0443). TNEs occurred more frequently in childhood moyamoya disease patients than expected. The clinical background, including symptoms, timing, and duration, was almost identical to TNEs in adults. Focal hyperperfusion, rather than numerical global hyperperfusion, was strongly correlated with the incidence of TNEs. Furthermore, the authors advocate the notion that a clinical course where symptoms occur without triggers may be a unique characteristic of TNEs, especially in childhood moyamoya disease.

The biomechanical signature of loss of consciousness: computational modelling of elite athlete head injuries.

Sports related head injuries can cause transient neurological events including loss of consciousness and dystonic posturing. However, it is unknown why head impacts that appear similar produce distinct neurological effects. The biomechanical effect of impacts can be estimated using computational models of strain within the brain. Here, we investigate the strain and strain rates produced by professional American football impacts that led to loss of consciousness, posturing or no neurological signs. We reviewed 1280 National Football League American football games and selected cases where the team's medical personnel made a diagnosis of concussion. Videos were then analysed for signs of neurological events. We identified 20 head impacts that showed clear video signs of loss of consciousness and 21 showing clear abnormal posturing. Forty-one control impacts were selected where there was no observable evidence of neurological signs, resulting in 82 videos of impacts for analysis. Video analysis was used to guide physical reconstructions of these impacts, allowing us to estimate the impact kinematics. These were then used as input to a detailed 3D high-fidelity finite element model of brain injury biomechanics to estimate strain and strain rate within the brain. We tested the hypotheses that impacts producing loss of consciousness would be associated with the highest biomechanical forces, that loss of consciousness would be associated with high forces in brainstem nuclei involved in arousal and that dystonic posturing would be associated with high forces in motor regions. Impacts leading to loss of consciousness compared to controls produced higher head acceleration (linear acceleration; 81.5 g ± 39.8 versus 47.9 ± 21.4; P = 0.004, rotational acceleration; 5.9 krad/s2 ± 2.4 versus 3.5 ± 1.6; P < 0.001) and in voxel-wise analysis produced larger brain deformation in many brain regions, including parts of the brainstem and cerebellum. Dystonic posturing was also associated with higher deformation compared to controls, with brain deformation observed in cortical regions that included the motor cortex. Loss of consciousness was specifically associated with higher strain rates in brainstem regions implicated in maintenance of consciousness, including following correction for the overall severity of impact. These included brainstem nuclei including the locus coeruleus, dorsal raphé and parabrachial complex. The results show that in head impacts producing loss of consciousness, brain deformation is disproportionately seen in brainstem regions containing nuclei involved in arousal, suggesting that head impacts produce loss of consciousness through a biomechanical effect on key brainstem nuclei involved in the maintenance of consciousness.

The usefulness and safety of dexmedetomidine for postoperative sedation in pediatric patients with moyamoya disease.

After revascularization surgery in pediatric patients with moyamoya disease (MMD), resting and avoiding crying is important. However, this inaction is often difficult because of pain or anxiety. Dexmedetomidine (DEX), which has sedative and analgesic properties, may be useful in reducing those uncomfortable conditions; however, its common side effects include bradycardia and hypotension, which have a risk of decreasing the cerebral blood flow. The aim of this study was to investigate the efficacy and safety of using DEX for pediatric patients with MMD in the acute period after revascularization surgery. This retrospective study included pediatric patients with MMD who underwent revascularization surgery. Based on whether DEX was used for light sedation during postoperative days (PODs) 0-1 after extubation, the patients were divided into DEX or control groups. For neurological outcomes, the incidence of symptomatic cerebral infarction and transient neurological events (TNEs) during PODs 0-1 and the entire hospitalization were investigated. In addition, the Richmond Agitation-Sedation Scale (RASS) was used to assess the effect of DEX, and bradycardia and hypotension were evaluated as side effects. A total of 84 surgical procedures were included in this study (27 in the DEX group and 57 in the control group). During PODs 0-1, symptomatic infarction was not observed in either group. The incidence of TNEs was almost the same in both groups: 2 (7.4%) of the 27 procedures in the DEX group and 4 (7.0%) of the 57 procedures in the control group (p > 0.99). Moreover, the incidences of symptomatic infarction and TNEs during the entire hospitalization did not differ significantly (symptomatic infarction, p > 0.99; TNEs, p = 0.20). Regarding the DEX effect, the median RASS scores during PODs 0-1 were -1.0 (drowsy) in the DEX group and +1.0 (restless) in the control group, showing a significant difference (p < 0.01). Regarding side effects, bradycardia was observed only in 3 (11.1%) of the 27 procedures in the DEX group (p = 0.03), and hypotension was not observed in any of the cases. In pediatric patients with MMD who are extubated after revascularization surgery, DEX produced appropriate light sedation and analgesia. The risk for symptomatic infarction is almost the same in cases in which DEX is used and those in which it is not; however, neurosurgeons should be cautious of bradycardia and TNEs as potential side effects.

Prevalence of Intracranial Atherosclerotic Disease in Patients with Low-Risk Transient or Persistent Neurologic Events.

There are limited data on the prevalence and outcome of intracranial atherosclerotic disease in patients with low-risk transient or persistent minor neurologic events. We sought to determine the prevalence and risk factors associated with intracranial atherosclerotic disease in patients with low-risk transient or persistent neurologic events. Participants with available intracranial vascular imaging from the Diagnosis of Uncertain-Origin Benign Transient Neurologic Symptoms (DOUBT) study, a large prospective multicenter cohort study, were included in this post hoc analysis. The prevalence of intracranial atherosclerotic disease of ≥50% was determined, and the association with baseline characteristics and DWI lesions was evaluated using logistic regression. We included 661 patients with a median age of 62 years (interquartile range, 53-70 years), of whom 53% were women. Intracranial atherosclerotic disease was found in 81 (12.3%) patients; asymptomatic intracranial atherosclerotic disease alone, in 65 (9.8%); and symptomatic intracranial atherosclerotic disease, in 16 (2.4%). The most frequent location was in the posterior cerebral artery (29%). Age was the only factor associated with any intracranial atherosclerotic disease (adjusted OR, 1.9 for 10 years increase; 95% CI, 1.6-2.5). Multivariable logistic regression showed a strong association between intracranial atherosclerotic disease and the presence of acute infarct on MR imaging (adjusted OR, 3.47; 95% CI, 1.91-6.25). Intracranial atherosclerotic disease is not rare in patients with transient or persistent minor neurologic events and is independently associated with the presence of MR imaging-proved ischemia in this context. Evaluation of the intracranial arteries could be valuable in establishing the etiology of such low-risk events.

Application of intraoperative electrocorticography in bypass surgery for adult moyamoya disease: a preliminary study.

Postoperative complications of surgical revascularization in moyamoya disease (MMD) are difficult to predict because of poor knowledge of the underlying pathophysiological process. Since the aim of surgery is to improve brain dynamics by increasing regional blood flow, we hypothesize that postoperative complications are closely related to aberrant electrophysiological changes. Thus, we evaluated the clinical significance of intraoperative electrocorticography (iECoG) in bypass surgery for adult MMD. Ninety-one adult patients operated on by the same neurosurgeon in our institute were involved (26 in the iECoG group, 65 in the traditional group). Two 1 × 6 subdural electrode grids were placed parallel to the middle frontal gyrus and superior temporal gyrus to record ECoG data continuously during the procedure in the iECoG group. Selected from several M4 candidate arteries, the recipient artery was determined to be closer to the cortex with lower power spectral density (PSD) in the beta band. The PSD parameter we used was the (delta+theta)/(alpha+beta) (DTAB) ratio (DTABR). Next, the pre- and post-bypass PSD values were evaluated, and correlations between post-/pre-bypass PSD parameter ratios and neurological/neuropsychological performance (in terms of changes in National Institutes of Health Stroke Scale [NIHSS] and Mini-Mental State Examination [MMSE] scores) were analyzed. Postoperative complications (transient neurological events) in the iECoG group were significantly lower than those in the traditional group (p = 0.046). In the iECoG group, the post-/pre-bypass DTABR ratio in the bypass area was significantly correlated with postoperative NIHSS (p = 0.002, r2 = 0.338) and MMSE changes (p = 0.007, r2 = 0.266). In the nonbypass area, neither postoperative NIHSS nor MMSE changes showed a significant correlation with the post-/pre-bypass DTABR ratio (p > 0.05). Additionally, patients with postoperative complications exhibited significantly higher DTABR (1.67 ± 0.33 vs. 0.95 ± 0.08, p = 0.003) and PSD of the theta band (1.54 ± 0.21 vs. 1.13 ± 0.08, p = 0.036). This study is the first to explain and guide surgical revascularization from the perspective of electrophysiology. Intraoperative ECoG is not only sensitive in reflecting and predicting postoperative neurological and cognitive performance but also usable as a reference for recipient artery selection.

Safety and Efficacy of Induced Hypertension and Hypervolemia in Preventing Neurologic Complications After Combined Direct and Indirect Bypass in Hemorrhagic-Onset Moyamoya Disease

Perioperative management of blood pressure in patients undergoing surgical revascularization for moyamoya disease (MMD) remains a controversial topic. We evaluated the safety and efficacy of induced hypertension and hypervolemia (IHH) in preventing neurologic complications during the perioperative period after direct surgical revascularization in a large hemorrhagic-onset moyamoya disease (HOMMD) cohort. We retrospectively reviewed a prospectively managed departmental database of all HOMMD patients treated between 1987 and 2019. The study included 122 direct surgical revascularization patients. Patients were separated into groups on the basis of the presence or absence of IHH therapy and evaluated for occurrence of 30-day risk of transient neurologic events (TNEs), ischemic, and hemorrhagic complications. Two-hundred and three revascularization procedures were performed on 122 patients for HOMMD treatment. Nineteen TNEs (9.4% of procedures) were observed in 18 (14.8%) patients. Two patients (1.6% and 1.0% of procedures) suffered from ischemic complications and 1 (0.8% and 0.5% of procedures) from hemorrhagic complications. No differences between groups in the severity, duration of TNEs, or length of hospital stay were noted. No patient in the IHH therapy group experienced a recurring TNE or readmission after discharge; however, this was not statistically significant owing to the small sample size. There were no differences in the rates of ischemic or hemorrhagic complications between groups with or without IHH therapy (P= 0.46 and 0.54, respectively). Induced hypertension and hypervolemia appear safe in HOMMD. There were no significant differences in complication or TNE rates between the groups with or without IHH therapy. While we believe it is important to employ IHH therapy in MMD patients who present with ischemic symptoms, these findings suggest that prophylactic IHH therapy may not be necessary in MMD patients presenting with hemorrhage.

Transient Focal Neurological Events in Cerebral Amyloid Angiopathy and the Long-term Risk of Intracerebral Hemorrhage and Death

Transient focal neurological episodes (TFNEs) are a frequently overlooked presentation of cerebral amyloid angiopathy (CAA), a condition with prognostic implications that are still not well described. To perform a systematic review and meta-analysis to examine the factors associated with incident lobar intracerebral hemorrhage (ICH) and death in patients with CAA presenting with TFNEs. A systematic review and individual participant meta-analysis including (1) a hospital-based cohort and (2) the results obtained from a systematic search performed in MEDLINE and Embase completed in December 2019. Included studies were observational reports of TFNEs. Patient-level clinical, imaging, and prognostic data were required for inclusion. For aggregate data studies, patient-level data were requested. Disagreements were resolved by consensus. Data were extracted following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines by 4 independent reviewers. The quality of reports was determined based on the modified Pearson Case Report Quality Scale. The clinical characteristics of TFNEs, neuroimaging features, and use of antithrombotics during follow-up were considered exposures. The predefined main outcomes were lobar ICH and risk of death during follow-up. Forty-two studies and 222 CAA-associated TFNE cases were included from the initial 1612 records produced by the systematic search; 26 additional patients (11 men [42.3%]; mean [SD] age, 77 [8] years) were provided by the hospital-based cohort. A total of 108 TFNEs (43.5%) consisted of motor symptoms. Convexity subarachnoid hemorrhage and cortical superficial siderosis were detected in 193 individuals (77.8%) and 156 individuals (62.9%) in the systematic search and hospital-based cohort, respectively. Follow-up duration could be obtained in 185 patients (median duration, 1 year [IQR, 0.8-2.5 years]). During follow-up, symptomatic lobar ICH occurred in 76 patients (39.4%). Motor symptoms (odds ratio, 2.08 [95% CI, 1.16-3.70]) at baseline and antithrombotic use during follow-up (odds ratio, 3.61 [95% CI, 1.67-7.84]) were associated with an increase in risk of lobar ICH. A total of 31 patients (16.5%) died during follow-up; lobar ICH during follow-up and cortical superficial siderosis were the main risk factors for death (odds ratio, 3.01 [95% CI, 1.36-6.69]; odds ratio, 3.20 [95% CI, 1.16-8.91], respectively). Patients presenting with CAA-associated TFNEs are at high risk of lobar ICH and death. Motor TFNEs and use of antithrombotics after a TFNE, in many cases because of misdiagnosis, are risk factors for ICH, and therefore accurate diagnosis and distinguishing this condition from transient ischemic attacks is critical.

Management of a first unprovoked epileptic seizure in adolescence and adulthood.

An epileptic seizure is one of the causes of so-called "transient neurological events" (TNEs). The differential diagnosis of a TNE relies mainly on history and physical examination. Laboratory markers are less frequently useful. After diagnosing an epileptic seizure, a distinction must be made between an acute symptomatic and an unprovoked seizure, since they have different treatments and prognosis. History, physical examination and other examinations (laboratory and imaging) are paramount in this distinction. After the diagnosis of a first unprovoked seizure, an EEG should be requested which may aid in establishing the diagnosis, evaluating the recurrence risk or ascertaining the self-limited nature of the seizure. 3T-MRI with an epilepsy protocol can be considered when CT has not clarified the aetiology. The decision to treat should be discussed with the patient/relatives, taking into account the risk of recurrence, the clinical characteristics (aetiology, seizure type, age, job, epileptic seizure schedule, comorbidities and polymedication), probability of AED side effects, and stigmatization. Nowadays, the chosen regimen is usually monotherapy with a second-generation AED that better suits the patient's characteristics, comorbidities and concurrent medication. Counselling should include first aid, precipitating factors, sport and physical exercise in order to avoid possible driving restrictions, the need for therapy compliance, and risk of recurrence and SUDEP.

Response To "Hemoglobin Concentration May Influence the Incidence of Postoperative Transient Neurological Events in Patients With Moyamoya After Extracranial-intracranial Arterial Bypass: A Retrospective Single Center Experience".

Response To "Hemoglobin Concentration May Influence the Incidence of Postoperative Transient Neurological Events in Patients With Moyamoya After Extracranial-intracranial Arterial Bypass: A Retrospective Single Center Experience".